Someone asked me what I thought of Bohr's remark, "shut up and do the math!" I said it was the honest answer: the math works, but we don't know why. Beyond our classical brains.
Without knowing quantum mechanic, I know the forms in the other side of the double slide, that is life (white energy) in this life and the next one stay in the light.
This is by far the best discussion of the double slit experiment on the internet. Thank you so much for showing the real physical instrumentation and calculations behind single electron interference experiment.
when I saw the title, I was hesitant to watch it (double slit experiment, yawn, boring). But Im glad I did. This is SO exciting! Best video on UA-cam about the subject so far. More please!
It is fascinating watching someone actually do the experiment.And not have t9 listen to a quantum nutter go on with abosolutely zero understsnding of the importance of experiments. Nonetheless it is a shame that after all his brilliant experimental work ...Professor Huygens from Hilversum didn’t realise you don’t need quantum probabilities to explain ALL his observations. ua-cam.com/video/_KekfbrzO74/v-deo.html
@@schmetterling4477 Lol, most highschools in the U.S. do not even require physics as a highschool class let alone teach QM. College maybe but not everyone takes physics there either. Many students across the world are never exposed to actual experiments. How many have seen the experimental apparatus that revealed the structure of the atom?
If everybody just demonstrate the experiments like this instead of talking about them, we would progress with science much faster. Thank you very much! Please do some videos on topics such as entanglement, and quantum eraser as well.
@@schmetterling4477 doesn't matter what u did that test won't show u crap. but funny ways to make light reflect off other objects. you cant reduce light to a single photon cuz its not a photon. its a perturbation
well when you us a microscope and plates of glass u give light multiple surfaces in witch to reflect off of. u kind defeat the purpose of the proof something is as u say u are doing. and then the reflection back from the observers eye no matter what object u choose to view said projection of partical physics. u should really pay more attention to things. light is much like sound. there is no emission from your mouth u simply make a disturbance in the air. well light is just a disturbance in the aether. not my words ether. nicola tesla and many others figured this out.
oh my god thank you! i've heard about the double slit experiment so many times without actually seeing it i was beginning to think nobody had actually done it.
@@gekkkoincroe there were chapters about the double slit experiment in my text books but they always just showed illustrations of how the experiment worked theoretically.
Phenomenally clear explanation, it makes the idea of wavefunctions very intuitive. Your mention of stimulated emission led me to think of a fun experiment (but one that’s unfortunately far beyond any capabilities I personally have): Suspend an atom or small cloud of atoms in a laser trap. Hit them with a higher-energy laser pulse to kick electrons into higher orbitals, so they’ll emit photons as they fall back to ground state. That would give you single-photon emitters with very constrained spatial distribution. Now put single slits *on opposite sides” of the atom trap and arrange mirrors and other optical elements to have Identical path lengths to a detector. You’d get interference patterns corresponding to single photons that “traveled” in opposite directions a the same time! 😄 It would be no different than a conventional double-slit experiment mathematically but would make the result that much more mind-boggling. No need for it, really; a conventional double slit is no less inexplicable classically, it’d just be fun to do :-)
It's a shame you don't have the capabilities, I'd like to see the results of this. I'm tired of an arrogant group of gate-keeping academic narcissists hogging picking and choosing which observations and discoveries to make public, and which to make unavailable to we underlings (either because in their hubris, assume "you can't handle the truth", or sense it may be of value to some monolithic corporation). Researchgate have started charging a fortune to even read peer reviewed papers, while others are written in unnecessarily complex language ("shibboleth").
A) Atoms have more than one electrons so you won't be getting a single photon emission (H atom don't count because it's much smaller then others ) B) the poton emission will be still be corresponding to electron presence cloud you can't determine or control the direction of emission We have LHC colliders and Nuclear Reactors which are closer to Atomic manipulation but not quite efficient Tools in hand to test your expectations.
Just a note, this is an excellent demonstration! A "single photon" could be interpreted as a single photon emitted during the coherence time or fluctuation of the laser, or the time the laser decorrelates its signal due to spontaneous emission (quantum fluctuation) . For example, a typical longitudinal single-mode HeNe might have a bandwidth of around a few hundred MHz (depending on the finesse of the cavity), and the photon number during a single coherent time can be modeled as a Bose-Einstein distribution with the average number of photons being much less than one for "single photon" during the coherence time (about 2 ns). It has more to do with the coherence time because if the single-photon beam is delayed more than this time, then a single photon won't interfere with itself, and no such the travel time from the source to the detector. The conclusion is the same though, that uncorrelated photons interfere with only themselves. Also, according to quantum path integration methods, a particle (including photons) actually takes any path, even paths where its speed can be greater or less than the speed of light. However, the "stationary" paths corresponds to those which constructively superimpose which corresponds to the outcomes where it almost overwhelmingly is certain to be observed traveling near light speed. Because the wavefunction of the photon is itself uncertain, there is uncertainty in the measurement of its phase and the wavenumber from which its speed is inferred which is why the stationary paths may not correspond precisely to the speed of light. In this interpretation of the double slit experiment, there are two stationary paths corresponding to the possible paths between the two slits that superimpose. If the slits were brought together and merged, the two sets of paths would constructively interfere into a single stationary path as they correspond to a single slit. According to the geometric theory of diffraction, there are additional paths corresponding to the diffraction from the edges of the slits as well, and the scattering between the edges of the slits, etc., which make progressively smaller contributions to the diffraction pattern.
2 роки тому
I wish I could understand this explanation. It is the most mysterious part of the experiment in my opinion.
Thank you so much for putting in the blood, sweat and tears to actually provide this video. Thank you for lying awake at night contemplating this. Thank you for sharing. I've seen countless explanations for what I'd say was one of the greatest mysteries and experiments of all time, the duality of light. Yet, because you accepted this challenge and chose to share it, you've given me and countless others an understanding that no longer requires conjuring of observers or the consciousness of matter. Light behaves the way it does through a purely physical means, and while QM is amazing at predicting the outcome, it is not the process in which it actually occurs.
as misleading as it sounds. observer in physics does not have anything to do with consciousness of matter, it just means ’particle that can interact with other particle’
@@scrung , I agree completely! Unfortunately some quantum physicists claim that interaction between particles is not observation (or measurement) and it wouldn't lead to the results of a Collapse. And I think they're still on the hunt of a physical Collapse. So far I haven't seen any good explanation of this "consciousness" ideas - they seem to only produce paradoxes (which are clear sign that at least one of their assumptions is wrong).
I generally share your sentiment. And really appreciated Huygens Optics efforts (I would even like more variations of the experiment and more details)! :) Just few things to clarify: - "duality of light" Actually I think all elementary particles show particle-wave duality (some like the electron more, some like photon a little less). D-Slit exp. was reproduced with protons and even with small molecules and still shows wave-like behavior. What I've found out after years of digging in the subject (I'm not a scientist, so I depend on videos & articles like this) is that most elementary particles are indeed somehow quantized (ie electron can have only very specific properties for example), but apparently their fields (which QFT is all about) are not quantized. I see real reluctance among scientists to consider the fields are non-quantized physical fields (which can be traced back to the disproval of Ether :)). But if you consider a field that can be affected by its particles and that it can affect them in return to be real - then I don't know what's all that fuzz about. Sure usually the fluctuations in these fields are normally so tiny that we can't detect & measure them (though things like the Casimir effect are most likely such result). - I agree completely that conjuring conscious observers (or Many Worlds :)) is completely unnecessary. Things have acted the same way long before us, and are still acting the same way on planets and stars where no conscious life (that we know of) is possible. The whole idea is so weak logically and should've been put to rest with logical arguments (no QM needed), but popularity of wrong interpretations have created the confusion imho. However to elaborate a bit. D-Slit experiment on its own doesn't raise the notion of conscious observer. The question "which path?" does in the variants that show particle-like behavior when one slot is closed (or the particle path is detected in some way). And still without more knowledge it's more likely that attempts to detect "which path" are affecting the particle behavior way more than a "conscious observer". Actually I've been rather frustrated, because in most videos they claim all the experiments have been done incredibly precisely and cleanly (which should be the first thing to doubt and double-check) and they are asking us to take on faith that "conscious observer" is the only possible explanation. But one example why at least many of these experiments were really lousy is that you don't need TWO Slits to see interference patter. You only need ONE slit! One slit still have two EDGES and the diffraction of both edges causes interference pattern (some of these wrong imo interpretations even use the Single-Slit-Interference to show the real world manifestation of the Heisenberg Uncertainty Principle). But how can one say that closing one slit produces particle-like beam on the screen, when it's really easy to produce interference pattern (with a narrow enough single slit). It seems to me people in general (and many scientists are no exception) prefer to explain the results of their own laziness and lack of creativity by paradoxes and mysteries :) - "Light behaves the way it does through a purely physical means" Again I agree that deterministic Universe is way more likely, and I prefer that hypothesis, even if I can't really prove it (but I can see logical errors in the efforts to prove it's not deterministic!). But to clarify QM (even with some of its ridiculous assumptions) is apparently great description of the fundamental particles. Yes naturally because of the extreme difficulties to observe them directly it has come to more of a statistical approach and the fine processes are still mostly a mystery, but the outcomes are clear in most cases. The main problems with the Standard QM are imho the Superposition & Collapse and that it insists that everything is only a cloud of probabilities until measured. Ie the main problem with QM is the Measurement Problem (which again shouldn't be surprising as we can't bounce smaller particles of when we're trying to observe the smallest particles). Just turning our inability into some physical aspect of Reality seems really wrong logical decision (it actually seems to be driven entirely by bias). There are actually deterministic & realistic quantum theories (mainly the Pilot-Wave theory) that don't have the weird assumptions of the Standard model of QM, and don't lead to such crazy paradoxes or conclusions. But unfortunately Pilot-Wave theory is not really developed theory. It was first conceived by Louis De Broglie (one of my favorite geniuses :)) at around the time the Standard (aka Copenhagen) interpretation was born. De Broglie presented his Pilot Wave Theory in 1924, but was shot down by the Copenhagen interpretation supporters. And instead of solving its issues and improving it De Broglie just gave up on it. In 1952 David Bohm revived it (some say independently of De Broglie's concept), but again it was shot down by some scientists (and David Bohm was unpopular person because was a victim of McCarthyism and investigated for links with communists). It was shot down even by Einstein, mainly because it's a non-local theory (despite that all De Broglie, Bohm & Einstein liked the hidden variables idea). Today Locality is mostly dead (preserved only by the explanation that while quantum entanglement does appear to be superluminal it's still not possible to transmit info faster than light), but Standard QM (and esp. QFT) still rely on Locality. So to summarize Standard QM is great and the most precise science we have so far, but its interpretation and philosophy are indeed really weak. And when you try to answer HOW something work you get in such waters, but Standard QM doesn't even try to answer them and just prefers to "shut up and calculate" :)
Excellent -- I could use an explanation of q-bits. Every one I watch or read that is non-specialist is the same -- "a q-bit can be both 0 and 1 and .... ... really fast."
A qbit is a vector bit. |0⟩ and |1⟩ form an orthonormal basis for a vector space. A qbit can be any 2d vector in that space. A qbit's state vector, |q_{0}⟩ entirely describes the qbit. For example, a qbit could have state vector |q_{0}⟩=a|0⟩+b|1⟩, where a and b can be any complex numbers. To find the probability of measuring a state |ψ⟩ when in the state |x⟩, the equation p(|x⟩)=|⟨x|ψ⟩|^2 is used (p finds the probability, values between ⟨ and | indicate row vectors while values between | and ⟩ indicate column vectors, magnitude notated as usual with ||). Note that row vectors and column vectors are related by the usual conjugate transpose, nothing new here. So the probability of being in state |x⟩ is the square of (the magnitude of (the inner product of (the conjugate transpose of the state |x⟩) with the state being measured, |ψ⟩)). qiskit.org/textbook/ch-states/representing-qubit-states.html is a good explanation that doesn't shy away from notation (and happens to be documentation for a simulator which will let you play with this stuff more directly).
You are a wonderful science communicator. You are the first person to explain the double slit experiment with a comprehensive guide and common sense. Congratulations! I'm subscribing. Please keep up the good work.
Hazzard Warning: While I normally despise many hazzard warnings, because the dangers are obvious, in this case I would suggest having one. "Don't look through a microscope that uses a repurposed Laser-Source with your bare eyes, because it can damage your eyes and could kill your eyesight - only let a camera look through it"
You are absolutely right. I myself used a camera to explicitly avoid this risk. But looking at a laser beam under a microscope can very easily damage your eyes. I will place an additional warning in the video description. Thanks for this comment.
Parts of this were presented in ways I haven't seen before, including quantum physics courses at uni. I definitely have a deeper understanding of some aspects now, really well done video!
I just lost my word with your explanation. The topic was familiar and I knew before but still I have learned a lot. Thanks for every effort you put in every single video.
I along with the many other commenters are amazed at your set up, description, and presentation of optical interference. The detailed explanation of the construction and set up and devices is an added bonus to me. The quantum mechanical explanation of photon creation and wave function is outstanding along with the many model depictions. Glad I found your channel. Thank You!
This is really the real double slit experiment. 0% show 100% scientific I love your channel sad that I didn't discover it sooner. Your Channel is very highly underrated. Well done, it is very indepth. Keep it up! I love it that you even show us equations and the math behind it, what other UA-camrs deliberately remove to get higher viewing rate for commercial reasons. You are the exception. Btw. I discovered your channel yesterday and I'm devouring all of your videos they are really high-quality in puncto education.
I don’t know didley about physics. But, I might have learnt something here. I’m not sure what I learnt, but I was impressed. As he said, not just diagrams and blah blah. Photographic demo.
Outstanding video! The fact that you did experiments and not simulations makes the video very valuable. It should be shown to students for educational purposes. Maybe you could summarize the outcomes of your work in a little document with some pictures in it.
This is the best presentation and explanation on the double slit experiment I've ever seen! And I love the fact that you showed how you perform the experiment and all the calculations without "dumbing down" or obfuscation. It introduces transparency, and is desperately needed when a lot of people are starting to doubt science.
the number on rule is that a particle takes all possible paths to get from A to B. Each path has an amplitude and phase, they all get added up, and that's the total amplitude (which is the square root of the probability). Since the phase is stationary at the "classical" path, paths near that add coherently and it "looks" like it took that path. But when you add tricks like 2 equal paths (slits), you can't hide the quantum nature that it really took ALL paths.
quantum particles do not have a definitite position, it is described by a wave of probability which travels- now you might imagine a ball traveling as the wave and then hitting something, like a billard ball, however what quantum particles actually do is that they literally don't "exist" until it interacts with something, so only the probability wave exists in travel time. The single wave travels and is diffracted between both slits- this then interferes with itself and where peaks and peaks overlap you have high probability, and where peaks and troughs overlap you have 0 probability
@@asdfniofanuiafabuiohui3977 I don't like this interpretation. Quantum mechanics is just an approximation, so there is no need to get into existing or not existing. I'm also concerned about calling the wave function "waves of probability". Everyone does it, but it's not probability, it's the square root of probability,...whatever that is.
@@DrDeuteron A "probability" and a "square root of probability" are really describing the same underlying entity, so the square root really only matters when doing the calculations. So in my limited understanding, calling it "waves of probability" is perfectly fine.
Most educational videos on the topic fail to convey how mindblowing quantum physics is, whereas this video really does an exceptional job at explaining it.
Sweet. I remember doing this experiment (using photomultiplier that scans the pattern at a distance few meters away) at my university long time ago. It was very clean, but it tooks few hours to prepare all the equipment (focusing, dark room, etc. etc), about 10 minutes to gather the single run of data, and many more hours or days to process (including calibration, both spatial, temporal and intensity, as well axis misalignments) or fit stuff in. The high intensity, 2D array and real time processing here are just so much better really for education, and with just a bit more work, it could be calibrated too to provide very decent results.
Yeah , I have actually been wondering why this single photon experiment was so incredibly easy. I guess being right on top of the slits makes that very little "probability" 😉 gets lost...
Huygens Optics - two issues that continue to haunt me, for the past 40 years, are: 1) are we not seeing the vibration of the atoms of the slit itself, 2) that the photons entering one slit do not have the same travel distance as the photons entering the other silt, they travel a different distance from origin to the slit (should already be out of phase with each other).
@@KK-pq6lu @10:00 he places the focal plane on the slits and two individual lines are seen. This tells me that the wall is absorbing the photons and working like an antenna, the free electrons are having energy added to them and where the energy pinches a photon is released. As for "2)", think of the photon as having a phase as it rotates and the phase would add or subtract from the wave front of free electrons in the material that the light is hitting. Capacitance just makes the wave guide shorter, it doesn't make it disappear.
SoosV -- let’s assign the line from the photon source to the slits to the screen as the x-axis. The photons arriving at one slit came from some x position but not necessarily from the same x position as the photons arriving at the other slit. Therefore, there is an inherent phase uncertainty between the photons arriving at one slit versus the photons arriving at the other slit during the same epsilon time interval. Even treating a photon as a wave does not remove the phase incoherence, and even dispersion, from the double slit experiment. I proffer to say that the double slit experiment has been misinterpreted for this past century, akin to the misinterpretation of Brownian motion that lasted almost a century.
I recall doing this experiment back in 1983 with a couple of razor blades to form a slit. I failed... Thanks for posting this. It's very much a subject that makes my head hurt, but it was worth it to see the experiment done properly.
Thank you for being the most practical, demonstrative, and well explained double slit video! I had such a hard time with the other ones because they never did use real data and perform the experiment in real time, just went with probability data. Everyone kept saying that by measuring one particle at a time, the interference pattern is removed, but I wanted to see it myself to understand it, and now I get it! The interference pattern still happens, but by measuring it, you simply create a defined path/possibility for each particle. Thank you for such a well informing video!
@@Ritefita According to my understanding, when you detect the individual photons then you stop getting a diffraction pattern and you get only 2 lines for the 2 slits photons can pass through.
This is the one. I kept searching and searching for actual application of the experiment and proper explanation of the "quantum weirdness" we can see happen. You broke it down into simple concepts that were easy to digest and you just got a new sub :)
Perhaps an experiment produced in the early 60's would be of interest too? ua-cam.com/video/tY3_78ONkmI/v-deo.html Note that several different experiments are performed, from light to VHF frequencies.
It's an amazing time to be alive. First, allow me to give a lot of respect to the designer of this experiment. Sheer genius in using off the shelf parts to do what even a few years ago would have been outside the means of anyone not being funded for defense. Also though, it shows us how technology democratizes science. Anyone with the gumption and a bit of technical knowledge can do this and so much more because technology gives us these high precision tools at a cost that follows the same curve that drives innovation, ala Moore's Law. It's so exciting to think of a reality in which anyone can be the next great discoverer of the laws of our universe.
I still think we have jumped to irrational conclusions. I believe much more experiments need to be conducted on the single slit diffraction phenomena, Huygens infinite wave front explanation does not sit right with me considering the interference is derived from the edge's of the single slit ,the math places the source of the wave at the edge of the slit Also need more attention should be directed to single laser beam interference. Say i shot a laser beam ,split the beam then converge it like this ---- I would like to see clear interference from this experiment.
For a completely different, simple and logical field theory explanation you will understand, you can view my video, "Particle 2 Slit Experiments Explained By Paul Marostica". I have 8 videos on UA-cam. Search keywords: matter theory marostica.
Thank you so much! Finally a video of an actual double slit experiment and very well explained. Is it possible to do a wave function collapsing when observed experiment?
It's always a bit scary when one of your videos shows up. Usually the content is way over my head. But when I muster the courage to watch it, even if I only get half of what you say, it's still very entertaining. Thank you.
Not only is this by far the best explanation I have ever seen of the experiment I am now questioning how photons actually propagate from stars. Based on this explanation it seems s as if they should be everywhere on the surface of a sphere with the radius expanding at the speed of light. But how does the inverse square law work in this case? Thanks for the stellar explanation. Now I have to go find the answer to my question.
Nice pun :D for whom it may concern the answer to this question could be that the probability of detecting a photon at a given point decreases with the square of the distance, hence inverse square law. If the probability of the entire photon sphere adds up to 1 it stands to reason that the larger it is, the lower the probability is at any given point so the sum is still 1. This is just my theory though so take it with a grain of salt.
YES YES YES. This is what ticks me off! People talk about things as if they know the., but then they don't disclose that extra detail that comes from experience; no mention of how they KNOW what they know. It is all so very logical until the experiment proves you wrong. This is why experiments and showing how they're done is important. I appreciate you. Subscribed.
Great video : I would have explained the pattern you see with one slit differently though. To me the pattern is formed from the diffraction pattern caused by the edge of the slit. To me this is reinforced by the difference we see when you show the different patterns for the gradient width. Overall great video!
You might be correct, that was my first guess as well. But then I would have expected a bright peak in the center of the slit position when going out of focus because of constructive interference originating from both edges equally. And instead you observe dark band in the center of each slit pattern, which I could not explain by just considereing diffraction at the edges. So, if you look at the inner 2 slits of the 44 slit experiment at 21:48 min, you see this interference pattern inside the slit when the slit is exactly in focus. It shows sort of a standing wave pattern, and that gave me the idea there might be specific wave modes inside the slit. Unfortunately there is not enough resolution to be sure.
@@HuygensOptics First, a great video with clear experiment. The single split experiment is diffraction from the edges. You can repeat this experiment with a single edge experiment by making the slit very wide. In this way you have the very basic experiment to show diffraction or the wave nature of light. Also, it would be nice if you could repeat the single, double and edge experiment with slits smaller than the wave length as some interesting things happens
@@ankhenaten2I'm not sure exactly what you ask proof off but I assume it is about the edge diffraction. As you might know, light behaves like waves in certain circumstances were it can go around objects in a wave form, this is called diffraction. With 2 edges, you are essentially creating a double slit experiment at each edge. You will find it in any basic physic book about light at university level. Otherwise just google "edge diffraction light" and look at the images. Let me know if you need more help.
Diffraction and interference are two aspects of the same wavelike nature of light. It makes no sense to argue what we, macroscopic apes, should call it.
That YT algorithm is pretty impressive.....I posted a comment on a movie (Black Easter) on how going back in time to change something is pointless because you'll never succeed, since you succeeding would eliminate the need to go back to change it in the first place (as per the Grandfather paradox). Someone replied, somehow we ended up at parallel worlds and the Penrose Interpretation and next I know YT presents me with this video. At first I thought it'd be boring but now I'm glad I watched this because you did a great job at not only explaining quantum mechanics and general relativity in a nutshell but also at showing it in progress. Excellent special sauce.
A photon potentially going anywhere the spatial geometry will allow, makes sense as with a strong enough beam, and sensetive enough detector, you will detect a photon at 180 degrees from whatever aperture its been emitted from....eventually.
This was the best explanation i ever heard of the double slit experiment and the probability function. You are easily one of the best when it comes to explaining deep concepts in a way that it can be easily understood.
I recently found this channel and am still watching videos to catch up. Every video has an education part to it that is exceptional. While I have heard and thought about these concepts before, i somehow feel like I understand them better and almost fully after your videos. It's crazy to reflect on that by the sheer amount of educational UA-cam videos I have consumed and also compared to stuff I learned at school or read in text book/wikipedia. Do you perhaps have more videos that look at photo statistics? I would love to understand better why the effective area of a pixel does matter more instead of the number of pixels in applications like astronomy but also video cameras. And how physics beat maths historically but (if you are interested in the advances or modern statistics and sensing) how it's turning around in the present day: maths beats physics Perhaps I should do an optics course at university next semester.
But why none shows when detectors are placed in the slits to see where the photon passed, so that the probability function should collapse and lose the interference pattern?
@@stalinbeltran4955 Boring? It would be awesome. Turn off the detector and we see interferences, turn on thr detector and we see two lines. It'd blow my mind.
So this made me understand that light is NOT simultaneously a wave and a particle, as sometimes stated, rather it is always a probability function until it is collapsed to a particle. Makes sense.
Not just that but the elementary particles are propagations of energy in their respective fields. A Boson particle is literally the presence of the energy of that specific field and it's very existence is what allows particles to have their mass. In fact that very particle is the glue that binds the other quarks together and acts as the "force carrier" for the other forces. It's what allows the weak force, strong force, gravity and electromagnetic radiation to interact with the particles.
I'd say that nobody doesn't actually know what any elementary particle is and why everything goes the way it does. All we have is set of facts and banch of assumptions. We can't even talk about existence of particle outside measurements. We cannot be sure that wave&particle properties are demonstrated either by particles or its classic characteristics like coordinate. Quantum physics itself can only predict what the probability of particular value in measurement, unfortunately, nothing more. Sad view but realistic. I consider, it's much better than belief in sumptions
There is no particle-wave duality, there is only waves. Particle theory only confuses people, Quantum Field Theory is the real meat that people should focus on. IMO particle theory shouldn't be taught in schools anymore, it's a waste of time.
Imagine floating above the ocean with a blindfold on. You are at an elevation that is at the peak of the wave. Periodically, you feel a force hit you. You say it's a particle because that's what it feels like. It's actually a wave... And the wave is made of smaller particles. Bearing in mind this analogy, there are waves in quantum fields. They are made of virtual particles that mediate this process, sort of like H20 molecules in our ocean wave, but with infinitesimally small lifetimes. If you can imagine an ocean of water molecules coalescing into a wave phenomenon, you can imagine a field of quantum virtual particles doing the same. Particles themselves are force carriers of the field they come from. When fields aren't static, they oscillate and a ripple of that energy propagates through space. This oscillation in a photon is its wavelength, which takes up physical space. Now imagine you take this spring and you confine it to dimensions smaller than the length of the spring. It interferes with itself and offsets the trajectory. These analogies should be taken with a grain of salt. The real understanding comes from a very deep understanding of math. When you can speak math and in your mind you see physical interactions, then you can build up into the quantum realm and the mathematics is guiding your visualizations. It's all still physics, but you get a clearer picture because you can see what's happening based on the math alone. Since the math is complex, most of us scratch our heads trying to understand what goes on. Tldr, think of photons as propagating springs. Then imagining how a photon can affect its own trajectory isn't so hard.
This was amazing. Just curious to see what happens to the interference pattern when you "measure" the photon as it goes thru one of the slits. In the typical explanation they always say that the interference pattern can be prevented if the photon is measured at one of the slits. This prevents the self-interference from occurring. Not sure how this would work exactly, though it's commonly espoused in many explanations.
remember that the photon probability can only go when there's no matter, so you just reconfigured the environment, putting a detector is the same as closing slit. unless somehow you can make a detector with 0 mass, but then by definition it is not a detector, as light can only interfere with itself, not with other sources
@@monad_tcp As a physics idiot, I'd love it if someone could explain to me why the camera doesn't function as a "detector" for this purpose. That's part of what has always baffled me about the description of the double-slit experiment: how does something "know" it has been measured? Why wouldn't the capturing of the state of the photon's waveform on a CMOS count for the collapsing of probability in the quantum realm?
@@VeganAtheistWeirdo I'll try my best to explain it, I'm only studying this as a hobby, I'm a MsC in computing science, not Physics. First you have to know what a detector is, detector is anything at all with interacts with the system (including the experimenter). The camera does function as a detector, but there's a difference, on where it is put. Something doesn't know it was measured, that's the entire point, its the observer who observe different results, because the act of observing changes the experiment, you are not decoupled as an observer. I like to think that if you put the detector in one of the slits, the detector itself will be entangled into the experiment, so the state of the detector is part of the experiment, and that's what collapses the wave-function (from the point of view of the other "detector", the experimenter). "Why wouldn't the capturing of the state of the photon's waveform on a CMOS count for the collapsing of probability in the quantum realm?" But It does do that, that's exactly why if you try to put the detector in one of the slits, it stops the photon from interfering with itself, its now interfering also with the detector. Which perhaps contrary to what you would think, makes the function collapse, the function won't collapse until its observed, aka, interacts with anything. Its opposite of what you think, the real mind-blowing is that the result changes depending on where you put the detector, aka, the observer changes the result of the experiment. But if you put the detector after the double slit, it gets the photon interfering with itself. If you think in terms of information, the detector when its on one of the slits just have half of the information, the other half is missing. So the photon will collapse on the detector with 100% of certainty, because you miss the rest of the data of the photon interference, so it looks like it is not interfering, but it still is (you need the entire state of the detector to see it now). The only way you could observe the photon interfering with itself is if you somehow entangled the entire detector with the experiment, but that's almost impossible to do, detectors are macroscopic objects that pretty much interact with the entire rest of the universe... Very hard to isolate, as you can do with a couple of particles.
"detectors are macroscopic objects that pretty much interact with the entire rest of the universe..." I mean, a CMOS camera as a detector. indeed a single particle would be a detector. One cool analogy, imagine trying to measure the speed of a car in a road by sending an speeding driver to crash into that car. That's how detection works, sure you can now know the speed of the car by crashing into it, but you changed the outcome of the experiment, and also lost all the other parameters, you don't know where the car was, only its speed because you knew the speed you sent you car to crash, and how far debree went. That's why anything at all with interacts with the system will make it collapse. It only does the quantum "thingy" when no one is looking, aka, no "collisions", no interactions. Bear in mind that all analogies break at some point, the only thing that always work is the math. Our *monke* brains don't have circuits to deal with it, we have to trust the math. Perhaps we are doing the cart before the horse, perhaps the universe does compute things lazy evaluated, instead of eagerly like we like our math... The universe calculates after the fact, the interaction happened, not before, that's why it looks like the probability knows before-hand which path it should go, and that it is obstructed by the detector before even reaching it. Its not that baffling if you think that way, its just go against common sense, but do remember that time don't pass for photons, so indeed, it can calculate things retroactively in time. And I only study that because I want to do cool things with quantum computers, all of this is just what I grasped at this moment, and probably is very much wrong, lol.
What confuses me is when the wave function "decides" to collapse. The photon interacted with not just the slits, but glass lenses, and gas molecules, but only collapsed on the ccd? Or did it maintain its ambiguity further? All the way to the camera's cpu?
Well, that is a matter of opinion I guess. PersonalIy I would limit the actual observation to the absorption of the photon, otherwise even your mother in law could get involved if she owns the computer. Generation of an entangled pair by a photon also counts as a detection event.
Huygens Optics Haha, you know you're into some esoteric science when opinion becomes a factor ;) So the photon's wave function travels along, interacting with the slits and glass and air but not getting absorbed until it reaches a ccd cell. Of course many never make it the whole way and are absorbed along the way, thus losing the information about the slits. Does placing the light filter after the slits change the outcome, I wonder.
@@HuygensOptics "Science " demands that you not get entangled with your mother-in-law (even if she owns a computer.) @Aaron Davidson thanks for making the point there is other 'stuff" that a photon "could" be partially absorbed by that "we" don't see (but discrete states prevent that ???). Was wondering about the difference experimentally between vacuum and air. The way I visualize the 'Wavicle" is a sphere or wave-front that has a slight rough -ish texture almost and the matter that finally absorbs the energy of the photon to also have a rough texture; so that wave-front could "ground out" have it's energy collapse at a myriad of different "contacting/interacting " points that are very hard to predict (almost analogous to predicting where lightning might strike / or visually analogous* (crudely and momentarily) to one of those plasma spheres. Really nice explanation of where the wave-front/wavicle/single photon can't go by Huygens Optics / Jerome. So my next question would be "What's the deal" with really larger molecules and even "macro structures/fluids" that are capable of interfering with itself ? ~ Are they quantum entangled or what's going on there ? @Jerome I thought you disappeared for a while but seems UA-cam didn't notify me when you made new videos - and now I see you have been super busy ! Veritable treasure trove here ; your videos should have waaaaaaay more views (shrugging shoulders) ~ I like your "ripples video" very three dimensional sense of the interference "structures" in 3d space. Heroic stuff going on here , really awesome. __________________________________________________________________ * My visual (mental really) analogy could be woefully wrong / contrived / counter indicated by actual 'Science". Thankfully my mother in law is not a quantum physicist... (but she does own a computer - shhhhhhh (tip toeing very quietly on egg shells ).
@@extradimension7356 thanks man. So about the bigger molecules: in principle they all obey Heisenberg, large or small. The only difference is that the effect of the uncertainty in momentum becomes less evident because of their much larger mass. So your experiment will require smaller slits, much closer together.
@@HuygensOptics I'll try it out ~ experimentally almost everything you do is very inspirational - going back to first principals and not taking anything for granted and strangely when you bounce out of that really reminds one there are still many many new types of photonic applications yet to be "Discovered" or put into action in new and useful ways and combinations that may have overlooked. The essence of how it REALLY goes (experimentally ) and the more subtle interactions and finer detail are so important I think . The point you made at the beginning of the video is very well taken. AND with the modern kit available now that can be scrounged / hacked together for not too much $. Incredible.
It’s a “wave” that sometimes gets measured as a particle. 😁 Edit: A discrete particle has wave-like properties. Our monkey brains see emergent physical properties. Conceiving a deterministic world takes a small leap but it will make perfect sense.
@@forsaturn4629 its just a wave ;) why complicate things? Would you say a duck in the middle of a lack swimming is EMITTING waves?? No! lmao you would say its causing them :) so what's causing the "waves" when you turn on a lightbulb? The bulb is not "emitting" light, its simply causing a phase change in the ether, which manifests as a disturbance that propagates at the rate of induction (which we call the speed of light, erroneously). “Light cannot be anything else but a longitudinal disturbance in the ether, involving alternate compressions and rarefactions. In other words, light can be nothing else than a sound wave in the ether.” -Nikola Tesla Things become so much more beautifully simple when you reject the cult of quantum
@@forsaturn4629 What is a field then? Modern Atomism and the cult of bumping particles cannot define a field ;) you guys only focus about QUANTIFYNG effects, aka COUNTING, aka MATH - DESCRIPTIVE, but not EXPLICATIVE. so, thusly, you are simply describing phenomenon - which is why so many of these "weird" things cannot be conventionally explained by Atomism: EPR paradox, spooky action at a distance, quantum tunneling, double slit interference - all of these are DIFFICULT to hold up to the light together under the minds of Atomists, yet it becomes beautifully more simple to explain if you simply start with the premise that the Ether exists as total potentiality (this was what the ether was once called). Suddenly, the double slit makes sense. Especially if its a wave of ether disturbance making its way towards the two slits at ~300 k/ms ;) The interference phenomena is then properly described using wave mechanics, and we don't have to futz around with particles that don't EXPLAIN the foundations of reality !!!!! it took me 2 years to break the programming of modern atomism, but if you truly (like I) have this urge to discover the meaning of reality - I will implore to watch this Polymath explain his theories ;) maybe you too one day can shed the mantle of the Cult of Atomism :) Mother nature does NOT have a bag of magic bumping particles lmao Light & Magnetism - Deepest Secrets by Ken Wheeler ua-cam.com/video/dQYkEVFQNDc/v-deo.html
A truly wonderful channel. EM radiation has always fascinated me. I have watched a couple of your videos so far and have thoroughly enjoyed your point of view on the matters!
Sir, great experiment. *SINGLE PHOTON* comment, because it is easy math that anyone can understand... With E=hv, the Frequency Term is in units Hertz, which is PER SECOND. Einstein's Photon energy idea is based on 1 second's worth of time, but is being used as INSTANTANEOUS. As you well know, if I had a 1 Ghz processor that would instantly switch on/off 1 billion times, instead of take 1 second, that would be a miracle. So how can Photon Energy be based of Hertz frequency and be instantaneous? OR, if you believe in the instant proportionality idea, then why would the Energy of a Photon be based on 1 second's worth of time? Does nature know how to build things via 1 second? E.g. A Red Photon ~400 Trillion waves occur in 1 second, so why would nature create INSTANT energy based on 1 second's worth of wavelengths? Either way you look at it (instant energy or energy that takes 1 second to build up), Einstein's Photon (or light quantum) can't be correct.
@My OhMy ** If you look at Max Planck's 1901 paper (where it came from), you will see that the value of "h" was derived by 1 seconds worth of Blackbody Power in Watts. If you claim e=hf is instant energy, then how does nature know to create instant energy photons that have *exactly 1 second's worth of wavelengths?* ** If the value of a Red photon (for example) *was based on math* that had 1 year's worth of Joule energy, then I guess you would claim that. When you read Einstein's 1905 Photoelectric paper, he claims light as a particle on emission and absorption events. OK, when does it ever become a wave? What is the process after emission that *transmutes* the photon into a wave that travels through space? If there isn't a mechanism, then light emission as a particle will always stay a particle during transmission until absorption. So, if you claim light is a particle, then how do you explain the double slit experiment? It is obvious from the Point A (emitter/source) to Point B (receiver/destination) that light is travelling as a wave through space, because of diffraction. It is obvious that light *IS NOT* travelling through space as a particle (because of diffraction). It is just using common sense, and basic high school algebra to show Einstein's photon fallacy. Einstein *REQUIRED* the photon idea in order to write the Special Relativity paper, because relative simultaneity absolutely fails with LIGHT WAVES via AETHER MEDIUM. Light WAVES allow you to work with _TIMING/WAVEPERIOD, SPACING/WAVELENGTH_ and _MEDIUM DISTURBANCE ORIGIN,_ instead of just DURATION/SECONDS and SPACE/METERS and OBSERVERS (as in Special Relativity). ** Just image that the feeling is mutual about Einstein followers. I am trying to show a way out using basic reasoning and logic. It's a take or leave it deal, because I am not doing it for self-promotion.
@My OhMy ** I already explained why the sample size is relevant. Do you not understand what a debate is about or is your mind always just correct? ** You realize that Planck did not take the measurements right? The blackbody data was from supplied Kurlbaum and Rubens, which is what Planck's paper says. I would suggest--google: Planck "On the Law Of Distribution of Energy in the Normal Spectrum" In Section 3 - Numerical Values, you can verify. Most people that "understand" this stuff rarely read the original work and/or research the original history. Science then becomes a canonical doctrine of textbooks and professors.
@My OhMy ** Sounds good... And I will go look on Ebay for a 1 GHz Frequency CPU that processes 1 billion instructions per instant. Maybe Intel has released a new one of those...
Compared to other videos on this experiment this is much higher quality content then average, Still you cheapen any real derivative from this demonstration by jumping over the most crucial element, Have you isolated a single photon. I would say no
You're right lol, In order to observe single photon(quanta E=hv) of visible wave length 400 nm to 7.50nm you need to turn on and off of your laser or open and close the shutter of your camera 4*10^14 to 7.5*10^14 times per second.
I would say yes, he fired them off so slowly that at every moment most of the time there were 0 photons, while at other moments there was one. Only in 1 in many millions of times would there be 2 or more photons in the air. we did that by putting a very dark filter before the light source. The filter is so dark that it look many minutes to gather enough photons to make a grainy image on a sensitive cooled CMOS.
@@kapytanhook Imagine you had your cmos sensor and photon source in a completely sealed box with no visible light. Photons of many many other frequencies are still present. thermal imaging inside the box would be easy proof, a gamma detector would also. "Photon" is not actually the name of brightness or packet of energy which happen in visible region. Even in darkness you will have also photons but in invisible region, due to the presence of matter at above Absolute Zero How can you claim single photon self interference when a photon free system currently is not known to exist. Even the most perfect vacuum surrounded by shielding and cooled to the record of the lowest temperature ever achieved in the universe -273.144 degrees Celsius (stunningly close to absolute zero) you still cannot claim you have a photon free system and without breaking the laws of thermodynamics you never will. Absolute zero cannot be reached because the temperature of the substance being cooled approaches the temperature of the cooling agent asymptotically, The kinetic energy of the matters ground state cannot be removed and hence neither can its photon emissions. Its paradoxical in a sense that you can never 100% discount the possibility that another photon wasn't involved in the detection event at the physical sensor or that the path of the detected photon was not interacting with other photons before the detection. Have you Isolated a single photon? I still say no.
@@aerosoapbreeze264 sure, honestly a very good point, photons of that wavelength maybe but there are trillions of thermal photons. It should be a different pattern though, the patterns are different for different frequencies. The fact that it closely matched shows that that laser's photons aren't affecting each other to cause that interference. But yeah I don't claim to understand what really causes light to behave this way. I find the idea of it being everywhere at once completely ridiculous, the wave function is a handy calculation tool, nothing more.
@@kapytanhook I Agree, and truly I'm not sure what the truth is but I do think some of the claims about the nature of quantum reality are logic breaking absurdities that I struggle to, or rather cant comprehend. I'm willing to go as far and claim that if the current list of supposed quantum effects are ultimately true, It's inherently impossible logically understand, A real Metaphysics.
Interesting how the narrator presents the relative simplicity and easy availability of the hardware used, seemingly ignoring the wealth of scientific knowledge necessary to put together these experiments and achieve similar results. And therein lies the beauty of science; he's right to emphasize that aspect. Knowledge is free for anyone to acquire. You don't need expensive schools or tools. Just time, dedication, imagination.
When I first saw the video title, I said: "Here goes another guy talking about the interesting double slit experiment again", which is quite interesting to me, but I thought I'd hear the classical ideas about it. Yet just a minute after I started I realized this video is totally different from what I have expected and heck, I loved it! Love your Dutch accent as well! It reminds me with my old days hanging around in the world with many Dutch colleagues. Thanks
Nice work! I do believe I understood your explanation, and was able to follow along. However, don't ask me to repeat that!!! Nice to see what you are doing with your machine, how you used it for creating the slits!!
Thank You! Best explanation ever... I've been scratching my head for decades about the photon's "behavior" concerning its position: not scratching anymore. I love all your vids. Thank you again.😁
I have to agree with the comment below...this was the BEST explanation that I have come across so far. I particularly learned how to explain how a SINGLE photon can travel through BOTH slits to create an interference pattern. MOre precicely, a photon's wave function travels in ALL directions at the same time *mind. blown* What I would want, is an explanation in THIS amount of detail of the quantum-eraser double-slit experiments.
This needs to be explained at this level but over a series of videos 10+ hours to be able to really dive in to de details of measurement and the effects of observers.
I never heard better explanation / experimental illustration that leaves no gaps for "magic" in a quantum phenomenon. Absolutely brilliant truly scientific explanation! This should be in text books everywhere!
Great video and an awesome demonstration of this experiment (which only just popped up in my YT feed) ! What I always point out to people is that the probability distribution does NOT mean the particle/photon has a definite position that we merely don't know about. What it means is the particle really DOES NOT HAVE a singular position until there is an interaction with something else. Also, it would be really cool if you could demonstrate the delayed choice quantum eraser experiment, which is even more mind-blowing.
I have done this double slit experiment when I was in high school. It was in our physics study syllabus. At that time I didn't know the importance of this experiment. Now, after about 15 years later I realized that this experiment is one of the very important phenomenon in quantum physics.
Well explained. Also leading on from this it explains why the speed of light is slower in materials than through the vacuum, because the photons have more possible paths to travel.
I watch a lot of educational YT, and your content is some of the deepest yet most accessible around.
“I think I can safely say that nobody really understands quantum mechanics.." (R. Feynman)
@@Volk715 "If you think you understand quantum mechanics, you don't understand quantum mechanics" (R. Feynman)
Someone asked me what I thought of Bohr's remark, "shut up and do the math!" I said it was the honest answer: the math works, but we don't know why. Beyond our classical brains.
Without knowing quantum mechanic, I know the forms in the other side of the double slide, that is life (white energy) in this life and the next one stay in the light.
Been looking for stuff like this..
This is by far the best discussion of the double slit experiment on the internet. Thank you so much for showing the real physical instrumentation and calculations behind single electron interference experiment.
when I saw the title, I was hesitant to watch it (double slit experiment, yawn, boring). But Im glad I did. This is SO exciting! Best video on UA-cam about the subject so far. More please!
Agreed!
I rarely subscribe to a channel after watching only a single video. I did here.
Double slit experiment boring? Oh man.. I'm sorry
@@JayPixx It is boring. It doesn't tell me anything new.
@@UsernameXOXO well you're missing the point then ; ) for it shouldn't get old until its nature is known
It is fascinating watching someone actually do the experiment.And not have t9 listen to a quantum nutter go on with abosolutely zero understsnding of the importance of experiments. Nonetheless it is a shame that after all his brilliant experimental work ...Professor Huygens from Hilversum didn’t realise you don’t need quantum probabilities to explain ALL his observations. ua-cam.com/video/_KekfbrzO74/v-deo.html
Very much appreciated this video. Finally, someone actually shows the experiment in action, with all the equipment being used!
I'm glad this video is now being recommended by the algorithm. It's a true gem, thank you!
Thanks.
So much confusion could be avoided by showing actual experimental results and avoiding strained or just incorrect analogies. Bravo!
@@schmetterling4477 Lol, most highschools in the U.S. do not even require physics as a highschool class let alone teach QM. College maybe but not everyone takes physics there either. Many students across the world are never exposed to actual experiments. How many have seen the experimental apparatus that revealed the structure of the atom?
A beautifully crafted demonstration, indeed! Thanks for taking the time and effort to share this kind of content.
Indeed !
If everybody just demonstrate the experiments like this instead of talking about them, we would progress with science much faster. Thank you very much!
Please do some videos on topics such as entanglement, and quantum eraser as well.
ur asking for a magic trick now. they still can not prove many of there clams to as this is how it works. still hunting dark anything lol.
You think that people who make progress needs this visual videos? Thats for the dummies like us :D
@@schmetterling4477 and u didnt do anything but make a bunch of places for light to reflect from.
@@schmetterling4477 true as tech grows we learn more. funny how there hand in hand.
@@schmetterling4477 doesn't matter what u did that test won't show u crap. but funny ways to make light reflect off other objects. you cant reduce light to a single photon cuz its not a photon. its a perturbation
This video needs more views. Your work is extraordinarily comprehensive and informative.
not really just repeating what others have said before.
@@EnergyTRE Those aren't mutually exclusive.
@@Not.So.WiseGuy comprehension does matter but if u actually understand it all this means nothing lol
@@EnergyTRE Cool, could you explain it all then?
well when you us a microscope and plates of glass u give light multiple surfaces in witch to reflect off of. u kind defeat the purpose of the proof something is as u say u are doing. and then the reflection back from the observers eye no matter what object u choose to view said projection of partical physics. u should really pay more attention to things. light is much like sound. there is no emission from your mouth u simply make a disturbance in the air. well light is just a disturbance in the aether. not my words ether. nicola tesla and many others figured this out.
oh my god thank you! i've heard about the double slit experiment so many times without actually seeing it i was beginning to think nobody had actually done it.
Wdym there's a whole chapter in physics "duality of light nature" in 12th class/grade/standard whatever you call in your country
@@gekkkoincroe there were chapters about the double slit experiment in my text books but they always just showed illustrations of how the experiment worked theoretically.
@@gekkkoincroeyou learn this at school? Haha the first world is awesome
Phenomenally clear explanation, it makes the idea of wavefunctions very intuitive.
Your mention of stimulated emission led me to think of a fun experiment (but one that’s unfortunately far beyond any capabilities I personally have): Suspend an atom or small cloud of atoms in a laser trap. Hit them with a higher-energy laser pulse to kick electrons into higher orbitals, so they’ll emit photons as they fall back to ground state. That would give you single-photon emitters with very constrained spatial distribution. Now put single slits *on opposite sides” of the atom trap and arrange mirrors and other optical elements to have Identical path lengths to a detector. You’d get interference patterns corresponding to single photons that “traveled” in opposite directions a the same time! 😄 It would be no different than a conventional double-slit experiment mathematically but would make the result that much more mind-boggling. No need for it, really; a conventional double slit is no less inexplicable classically, it’d just be fun to do :-)
That's a beautiful formulation, I'd really like to see that done
You should t have quit high school. Good luck
It's a shame you don't have the capabilities, I'd like to see the results of this. I'm tired of an arrogant group of gate-keeping academic narcissists hogging picking and choosing which observations and discoveries to make public, and which to make unavailable to we underlings (either because in their hubris, assume "you can't handle the truth", or sense it may be of value to some monolithic corporation).
Researchgate have started charging a fortune to even read peer reviewed papers, while others are written in unnecessarily complex language ("shibboleth").
A) Atoms have more than one electrons so you won't be getting a single photon emission (H atom don't count because it's much smaller then others )
B) the poton emission will be still be corresponding to electron presence cloud you can't determine or control the direction of emission
We have LHC colliders and Nuclear Reactors which are closer to Atomic manipulation but not quite efficient Tools in hand to test your expectations.
This is what real science looks like, kids.
Lol you’re funny
I’m not a kid
ok mr guitologist lmfaoooo
false. it is a reification of a mathematical model.
Good cause almost half of modern peer reviewed science is falsified. Read fashionable nonsense
Just a note, this is an excellent demonstration! A "single photon" could be interpreted as a single photon emitted during the coherence time or fluctuation of the laser, or the time the laser decorrelates its signal due to spontaneous emission (quantum fluctuation) . For example, a typical longitudinal single-mode HeNe might have a bandwidth of around a few hundred MHz (depending on the finesse of the cavity), and the photon number during a single coherent time can be modeled as a Bose-Einstein distribution with the average number of photons being much less than one for "single photon" during the coherence time (about 2 ns). It has more to do with the coherence time because if the single-photon beam is delayed more than this time, then a single photon won't interfere with itself, and no such the travel time from the source to the detector. The conclusion is the same though, that uncorrelated photons interfere with only themselves.
Also, according to quantum path integration methods, a particle (including photons) actually takes any path, even paths where its speed can be greater or less than the speed of light. However, the "stationary" paths corresponds to those which constructively superimpose which corresponds to the outcomes where it almost overwhelmingly is certain to be observed traveling near light speed. Because the wavefunction of the photon is itself uncertain, there is uncertainty in the measurement of its phase and the wavenumber from which its speed is inferred which is why the stationary paths may not correspond precisely to the speed of light. In this interpretation of the double slit experiment, there are two stationary paths corresponding to the possible paths between the two slits that superimpose. If the slits were brought together and merged, the two sets of paths would constructively interfere into a single stationary path as they correspond to a single slit. According to the geometric theory of diffraction, there are additional paths corresponding to the diffraction from the edges of the slits as well, and the scattering between the edges of the slits, etc., which make progressively smaller contributions to the diffraction pattern.
I wish I could understand this explanation. It is the most mysterious part of the experiment in my opinion.
Thank you so much for putting in the blood, sweat and tears to actually provide this video. Thank you for lying awake at night contemplating this. Thank you for sharing. I've seen countless explanations for what I'd say was one of the greatest mysteries and experiments of all time, the duality of light. Yet, because you accepted this challenge and chose to share it, you've given me and countless others an understanding that no longer requires conjuring of observers or the consciousness of matter. Light behaves the way it does through a purely physical means, and while QM is amazing at predicting the outcome, it is not the process in which it actually occurs.
Blood? Tears? Lmao you’re funny
@@holdendavid9025Says the clown 🤡
as misleading as it sounds. observer in physics does not have anything to do with consciousness of matter, it just means ’particle that can interact with other particle’
@@scrung , I agree completely!
Unfortunately some quantum physicists claim that interaction between particles is not observation (or measurement) and it wouldn't lead to the results of a Collapse. And I think they're still on the hunt of a physical Collapse.
So far I haven't seen any good explanation of this "consciousness" ideas - they seem to only produce paradoxes (which are clear sign that at least one of their assumptions is wrong).
I generally share your sentiment. And really appreciated Huygens Optics efforts (I would even like more variations of the experiment and more details)! :)
Just few things to clarify:
- "duality of light" Actually I think all elementary particles show particle-wave duality (some like the electron more, some like photon a little less). D-Slit exp. was reproduced with protons and even with small molecules and still shows wave-like behavior.
What I've found out after years of digging in the subject (I'm not a scientist, so I depend on videos & articles like this) is that most elementary particles are indeed somehow quantized (ie electron can have only very specific properties for example), but apparently their fields (which QFT is all about) are not quantized.
I see real reluctance among scientists to consider the fields are non-quantized physical fields (which can be traced back to the disproval of Ether :)).
But if you consider a field that can be affected by its particles and that it can affect them in return to be real - then I don't know what's all that fuzz about.
Sure usually the fluctuations in these fields are normally so tiny that we can't detect & measure them (though things like the Casimir effect are most likely such result).
- I agree completely that conjuring conscious observers (or Many Worlds :)) is completely unnecessary. Things have acted the same way long before us, and are still acting the same way on planets and stars where no conscious life (that we know of) is possible. The whole idea is so weak logically and should've been put to rest with logical arguments (no QM needed), but popularity of wrong interpretations have created the confusion imho.
However to elaborate a bit. D-Slit experiment on its own doesn't raise the notion of conscious observer. The question "which path?" does in the variants that show particle-like behavior when one slot is closed (or the particle path is detected in some way). And still without more knowledge it's more likely that attempts to detect "which path" are affecting the particle behavior way more than a "conscious observer".
Actually I've been rather frustrated, because in most videos they claim all the experiments have been done incredibly precisely and cleanly (which should be the first thing to doubt and double-check) and they are asking us to take on faith that "conscious observer" is the only possible explanation.
But one example why at least many of these experiments were really lousy is that you don't need TWO Slits to see interference patter. You only need ONE slit!
One slit still have two EDGES and the diffraction of both edges causes interference pattern (some of these wrong imo interpretations even use the Single-Slit-Interference to show the real world manifestation of the Heisenberg Uncertainty Principle).
But how can one say that closing one slit produces particle-like beam on the screen, when it's really easy to produce interference pattern (with a narrow enough single slit).
It seems to me people in general (and many scientists are no exception) prefer to explain the results of their own laziness and lack of creativity by paradoxes and mysteries :)
- "Light behaves the way it does through a purely physical means"
Again I agree that deterministic Universe is way more likely, and I prefer that hypothesis, even if I can't really prove it (but I can see logical errors in the efforts to prove it's not deterministic!).
But to clarify QM (even with some of its ridiculous assumptions) is apparently great description of the fundamental particles.
Yes naturally because of the extreme difficulties to observe them directly it has come to more of a statistical approach and the fine processes are still mostly a mystery, but the outcomes are clear in most cases.
The main problems with the Standard QM are imho the Superposition & Collapse and that it insists that everything is only a cloud of probabilities until measured.
Ie the main problem with QM is the Measurement Problem (which again shouldn't be surprising as we can't bounce smaller particles of when we're trying to observe the smallest particles). Just turning our inability into some physical aspect of Reality seems really wrong logical decision (it actually seems to be driven entirely by bias).
There are actually deterministic & realistic quantum theories (mainly the Pilot-Wave theory) that don't have the weird assumptions of the Standard model of QM, and don't lead to such crazy paradoxes or conclusions. But unfortunately Pilot-Wave theory is not really developed theory.
It was first conceived by Louis De Broglie (one of my favorite geniuses :)) at around the time the Standard (aka Copenhagen) interpretation was born. De Broglie presented his Pilot Wave Theory in 1924, but was shot down by the Copenhagen interpretation supporters. And instead of solving its issues and improving it De Broglie just gave up on it.
In 1952 David Bohm revived it (some say independently of De Broglie's concept), but again it was shot down by some scientists (and David Bohm was unpopular person because was a victim of McCarthyism and investigated for links with communists). It was shot down even by Einstein, mainly because it's a non-local theory (despite that all De Broglie, Bohm & Einstein liked the hidden variables idea).
Today Locality is mostly dead (preserved only by the explanation that while quantum entanglement does appear to be superluminal it's still not possible to transmit info faster than light), but Standard QM (and esp. QFT) still rely on Locality.
So to summarize Standard QM is great and the most precise science we have so far, but its interpretation and philosophy are indeed really weak.
And when you try to answer HOW something work you get in such waters, but Standard QM doesn't even try to answer them and just prefers to "shut up and calculate" :)
Excellent -- I could use an explanation of q-bits. Every one I watch or read that is non-specialist is the same -- "a q-bit can be both 0 and 1 and .... ... really fast."
A qbit is a vector bit. |0⟩ and |1⟩ form an orthonormal basis for a vector space. A qbit can be any 2d vector in that space. A qbit's state vector, |q_{0}⟩ entirely describes the qbit. For example, a qbit could have state vector |q_{0}⟩=a|0⟩+b|1⟩, where a and b can be any complex numbers. To find the probability of measuring a state |ψ⟩ when in the state |x⟩, the equation p(|x⟩)=|⟨x|ψ⟩|^2 is used (p finds the probability, values between ⟨ and | indicate row vectors while values between | and ⟩ indicate column vectors, magnitude notated as usual with ||). Note that row vectors and column vectors are related by the usual conjugate transpose, nothing new here. So the probability of being in state |x⟩ is the square of (the magnitude of (the inner product of (the conjugate transpose of the state |x⟩) with the state being measured, |ψ⟩)).
qiskit.org/textbook/ch-states/representing-qubit-states.html is a good explanation that doesn't shy away from notation (and happens to be documentation for a simulator which will let you play with this stuff more directly).
I LOVE your outro! You're totally right, "don't take my word for it, do your own experiments"
An excellent tutorial...best I've seen, cheers.
17:40 The sequence with Heisenberg’s eyes is both technically clear and poetic. Well done!
Wow that was awesome, the double slit experiment is one of my favorites.
You are a wonderful science communicator. You are the first person to explain the double slit experiment with a comprehensive guide and common sense. Congratulations! I'm subscribing. Please keep up the good work.
best video I have yet seen one youtube, extremely well done!
Hazzard Warning:
While I normally despise many hazzard warnings, because the dangers are obvious, in this case I would suggest having one. "Don't look through a microscope that uses a repurposed Laser-Source with your bare eyes, because it can damage your eyes and could kill your eyesight - only let a camera look through it"
You are absolutely right. I myself used a camera to explicitly avoid this risk. But looking at a laser beam under a microscope can very easily damage your eyes. I will place an additional warning in the video description. Thanks for this comment.
you saved my eye!!
I look at lasers all the time through a micro scope when i align cytometers! I hope to be blind next year so i can get workmans compensation! 👀
It's fine, just use the bad eye.
That's why I keep one eye designated for experiments only
Wow ! where were you when I was a physics undergrad. Love this.
THANK YOU! I HATE IT when people talk about experiments without doing them!
Even better is a simulation of an experiment.
Then you would not have liked to listen to Einstein, who reportedly was fond of « Gedankexperimenten». 😊
Parts of this were presented in ways I haven't seen before, including quantum physics courses at uni.
I definitely have a deeper understanding of some aspects now, really well done video!
I just lost my word with your explanation. The topic was familiar and I knew before but still I have learned a lot. Thanks for every effort you put in every single video.
Excellent as usual! One of the few channels I have notifications turned on for.
I along with the many other commenters are amazed at your set up, description, and presentation of optical interference. The detailed explanation of the construction and set up and devices is an added bonus to me. The quantum mechanical explanation of photon creation and wave function is outstanding along with the many model depictions. Glad I found your channel. Thank You!
Thanks for adding a bit more insight to something I've heard a hundred times.
This is really the real double slit experiment. 0% show 100% scientific I love your channel sad that I didn't discover it sooner. Your Channel is very highly underrated. Well done, it is very indepth. Keep it up!
I love it that you even show us equations and the math behind it, what other UA-camrs deliberately remove to get higher viewing rate for commercial reasons. You are the exception. Btw. I discovered your channel yesterday and I'm devouring all of your videos they are really high-quality in puncto education.
I was physics major. Surprised to see such a good and down to experiment video! Keep working on it bro!
I don’t know didley about physics. But, I might have learnt something here.
I’m not sure what I learnt, but I was impressed. As he said, not just diagrams and blah blah. Photographic demo.
Defininitely worth posting. Brilliant exposition of experiment and theory.
This is what I'm looking for a quite while.
absolutely fascinating. I've never seen anything like it, including at university physics lectures. You would make for an EXCELLENT lecturer
Outstanding video! The fact that you did experiments and not simulations makes the video very valuable. It should be shown to students for educational purposes. Maybe you could summarize the outcomes of your work in a little document with some pictures in it.
For sure!
This is the best presentation and explanation on the double slit experiment I've ever seen!
And I love the fact that you showed how you perform the experiment and all the calculations without "dumbing down" or obfuscation.
It introduces transparency, and is desperately needed when a lot of people are starting to doubt science.
Best explanation I have seen so far! I'm still confused though! Maybe before I die I'll understand this! Thanks 👍
the number on rule is that a particle takes all possible paths to get from A to B. Each path has an amplitude and phase, they all get added up, and that's the total amplitude (which is the square root of the probability). Since the phase is stationary at the "classical" path, paths near that add coherently and it "looks" like it took that path.
But when you add tricks like 2 equal paths (slits), you can't hide the quantum nature that it really took ALL paths.
quantum particles do not have a definitite position, it is described by a wave of probability which travels- now you might imagine a ball traveling as the wave and then hitting something, like a billard ball, however what quantum particles actually do is that they literally don't "exist" until it interacts with something, so only the probability wave exists in travel time. The single wave travels and is diffracted between both slits- this then interferes with itself and where peaks and peaks overlap you have high probability, and where peaks and troughs overlap you have 0 probability
@@asdfniofanuiafabuiohui3977 I don't like this interpretation. Quantum mechanics is just an approximation, so there is no need to get into existing or not existing.
I'm also concerned about calling the wave function "waves of probability". Everyone does it, but it's not probability, it's the square root of probability,...whatever that is.
@@DrDeuteron A "probability" and a "square root of probability" are really describing the same underlying entity, so the square root really only matters when doing the calculations. So in my limited understanding, calling it "waves of probability" is perfectly fine.
@@slartibartfast1268 the só called wave of probability actually really looks like the gaussian distribution, very normal and not wave like até ALL
Most educational videos on the topic fail to convey how mindblowing quantum physics is, whereas this video really does an exceptional job at explaining it.
Sweet. I remember doing this experiment (using photomultiplier that scans the pattern at a distance few meters away) at my university long time ago. It was very clean, but it tooks few hours to prepare all the equipment (focusing, dark room, etc. etc), about 10 minutes to gather the single run of data, and many more hours or days to process (including calibration, both spatial, temporal and intensity, as well axis misalignments) or fit stuff in.
The high intensity, 2D array and real time processing here are just so much better really for education, and with just a bit more work, it could be calibrated too to provide very decent results.
Yeah , I have actually been wondering why this single photon experiment was so incredibly easy. I guess being right on top of the slits makes that very little "probability" 😉 gets lost...
Huygens Optics - two issues that continue to haunt me, for the past 40 years, are: 1) are we not seeing the vibration of the atoms of the slit itself, 2) that the photons entering one slit do not have the same travel distance as the photons entering the other silt, they travel a different distance from origin to the slit (should already be out of phase with each other).
@AnubisPatron what are you trying to argue with that article? no one here is talking about consciousness.
@@KK-pq6lu @10:00 he places the focal plane on the slits and two individual lines are seen. This tells me that the wall is absorbing the photons and working like an antenna, the free electrons are having energy added to them and where the energy pinches a photon is released. As for "2)", think of the photon as having a phase as it rotates and the phase would add or subtract from the wave front of free electrons in the material that the light is hitting. Capacitance just makes the wave guide shorter, it doesn't make it disappear.
SoosV -- let’s assign the line from the photon source to the slits to the screen as the x-axis. The photons arriving at one slit came from some x position but not necessarily from the same x position as the photons arriving at the other slit. Therefore, there is an inherent phase uncertainty between the photons arriving at one slit versus the photons arriving at the other slit during the same epsilon time interval. Even treating a photon as a wave does not remove the phase incoherence, and even dispersion, from the double slit experiment. I proffer to say that the double slit experiment has been misinterpreted for this past century, akin to the misinterpretation of Brownian motion that lasted almost a century.
I recall doing this experiment back in 1983 with a couple of razor blades to form a slit. I failed...
Thanks for posting this. It's very much a subject that makes my head hurt, but it was worth it to see the experiment done properly.
Finally some real clarity thank you
Finally a two slit video done right.
Thank you very much!
Where did the rest of the video go? It was really good but stopped dead at 4:38 with a intensity-time graph and silence for the rest of the video >.>
Have a read of the description of the video
The original full length version was much better. I don’t know why he cut what I considered to be his best video.
Thank you for being the most practical, demonstrative, and well explained double slit video! I had such a hard time with the other ones because they never did use real data and perform the experiment in real time, just went with probability data. Everyone kept saying that by measuring one particle at a time, the interference pattern is removed, but I wanted to see it myself to understand it, and now I get it! The interference pattern still happens, but by measuring it, you simply create a defined path/possibility for each particle. Thank you for such a well informing video!
I missed the part where he "observes" the photon and it stop behaving like a wave...
I was just thinking the same thing - that part is missing and that is what made the experiment so famous.
starting from 14:51
and exact moment 16:08
@@Ritefita That is an explanation, not the experiment itself where only 2 lines are displayed when the photon is observed.
@@JohannY2 all photons were observed
and not observed ones
you didn't observe =)
@@Ritefita According to my understanding, when you detect the individual photons then you stop getting a diffraction pattern and you get only 2 lines for the 2 slits photons can pass through.
This is the one. I kept searching and searching for actual application of the experiment and proper explanation of the "quantum weirdness" we can see happen. You broke it down into simple concepts that were easy to digest and you just got a new sub :)
Perhaps an experiment produced in the early 60's would be of interest too?
ua-cam.com/video/tY3_78ONkmI/v-deo.html
Note that several different experiments are performed, from light to VHF frequencies.
It's an amazing time to be alive. First, allow me to give a lot of respect to the designer of this experiment. Sheer genius in using off the shelf parts to do what even a few years ago would have been outside the means of anyone not being funded for defense. Also though, it shows us how technology democratizes science. Anyone with the gumption and a bit of technical knowledge can do this and so much more because technology gives us these high precision tools at a cost that follows the same curve that drives innovation, ala Moore's Law. It's so exciting to think of a reality in which anyone can be the next great discoverer of the laws of our universe.
Thank you! It's been hard to find "real" experiments online. Everything else is as you said, others explaining it for you.
@@schmetterling4477 Thank you for that, I have seen some modern interferometer experiments but will check out Youngs paper, appreciate the info.
This phenomenon is so weird and mysterious, I still to this day has not heard an explanation that completely satisfy my curiosity.
Unfortunately, like he said, our monkey brains might just be too simple to understand anything more than big rock heavy.
Monkey brains actually lack a region of their brain compared to humans so at least we could eventually artificially enhance our brains unlike monkeys
have you heard of pilot wave theory?, it makes much more sense than how conventional quantum physics is taught
I still think we have jumped to irrational conclusions. I believe much more experiments need to be conducted on the single slit diffraction phenomena, Huygens infinite wave front explanation does not sit right with me considering the interference is derived from the edge's of the single slit ,the math places the source of the wave at the edge of the slit
Also need more attention should be directed to single laser beam interference. Say i shot a laser beam ,split the beam then converge it like this ----
I would like to see clear interference from this experiment.
For a completely different, simple and logical field theory explanation you will understand, you can view my video, "Particle 2 Slit Experiments Explained By Paul Marostica". I have 8 videos on UA-cam. Search keywords: matter theory marostica.
The camera footage plus the diagram showing vertical movement was a great look at this spooky stuff
Thank you so much! Finally a video of an actual double slit experiment and very well explained. Is it possible to do a wave function collapsing when observed experiment?
I'm surprised that's not shown, that's the interesting part of the experiment
It's always a bit scary when one of your videos shows up. Usually the content is way over my head. But when I muster the courage to watch it, even if I only get half of what you say, it's still very entertaining. Thank you.
Not only is this by far the best explanation I have ever seen of the experiment I am now questioning how photons actually propagate from stars. Based on this explanation it seems s as if they should be everywhere on the surface of a sphere with the radius expanding at the speed of light. But how does the inverse square law work in this case? Thanks for the stellar explanation. Now I have to go find the answer to my question.
Nice pun :D for whom it may concern the answer to this question could be that the probability of detecting a photon at a given point decreases with the square of the distance, hence inverse square law. If the probability of the entire photon sphere adds up to 1 it stands to reason that the larger it is, the lower the probability is at any given point so the sum is still 1. This is just my theory though so take it with a grain of salt.
I appreciate that you don't appear to have simplified things at the cost of relevant details.
This is a fantastic demonstration and explanation of the double slit experiment. Incredibly impressive.
YES YES YES. This is what ticks me off! People talk about things as if they know the., but then they don't disclose that extra detail that comes from experience; no mention of how they KNOW what they know. It is all so very logical until the experiment proves you wrong.
This is why experiments and showing how they're done is important. I appreciate you. Subscribed.
Great video : I would have explained the pattern you see with one slit differently though. To me the pattern is formed from the diffraction pattern caused by the edge of the slit. To me this is reinforced by the difference we see when you show the different patterns for the gradient width.
Overall great video!
You might be correct, that was my first guess as well. But then I would have expected a bright peak in the center of the slit position when going out of focus because of constructive interference originating from both edges equally. And instead you observe dark band in the center of each slit pattern, which I could not explain by just considereing diffraction at the edges.
So, if you look at the inner 2 slits of the 44 slit experiment at 21:48 min, you see this interference pattern inside the slit when the slit is exactly in focus. It shows sort of a standing wave pattern, and that gave me the idea there might be specific wave modes inside the slit. Unfortunately there is not enough resolution to be sure.
@@HuygensOptics First, a great video with clear experiment.
The single split experiment is diffraction from the edges. You can repeat this experiment with a single edge experiment by making the slit very wide. In this way you have the very basic experiment to show diffraction or the wave nature of light.
Also, it would be nice if you could repeat the single, double and edge experiment with slits smaller than the wave length as some interesting things happens
@@patnutoris4054 do you have proof of what you are claiming?
@@ankhenaten2I'm not sure exactly what you ask proof off but I assume it is about the edge diffraction. As you might know, light behaves like waves in certain circumstances were it can go around objects in a wave form, this is called diffraction. With 2 edges, you are essentially creating a double slit experiment at each edge. You will find it in any basic physic book about light at university level.
Otherwise just google "edge diffraction light" and look at the images.
Let me know if you need more help.
Diffraction and interference are two aspects of the same wavelike nature of light. It makes no sense to argue what we, macroscopic apes, should call it.
That YT algorithm is pretty impressive.....I posted a comment on a movie (Black Easter) on how going back in time to change something is pointless because you'll never succeed, since you succeeding would eliminate the need to go back to change it in the first place (as per the Grandfather paradox). Someone replied, somehow we ended up at parallel worlds and the Penrose Interpretation and next I know YT presents me with this video.
At first I thought it'd be boring but now I'm glad I watched this because you did a great job at not only explaining quantum mechanics and general relativity in a nutshell but also at showing it in progress. Excellent special sauce.
A photon potentially going anywhere the spatial geometry will allow, makes sense as with a strong enough beam, and sensetive enough detector, you will detect a photon at 180 degrees from whatever aperture its been emitted from....eventually.
Cool to think about but I wonder how long it would take to have a photon appear there at least statistically speaking
@@Xaddre funny thing about probability, they could detect a photon the first time they turn on whatever experimental apparatus, then never again.
This was the best explanation i ever heard of the double slit experiment and the probability function. You are easily one of the best when it comes to explaining deep concepts in a way that it can be easily understood.
I recently found this channel and am still watching videos to catch up. Every video has an education part to it that is exceptional. While I have heard and thought about these concepts before, i somehow feel like I understand them better and almost fully after your videos. It's crazy to reflect on that by the sheer amount of educational UA-cam videos I have consumed and also compared to stuff I learned at school or read in text book/wikipedia.
Do you perhaps have more videos that look at photo statistics? I would love to understand better why the effective area of a pixel does matter more instead of the number of pixels in applications like astronomy but also video cameras. And how physics beat maths historically but (if you are interested in the advances or modern statistics and sensing) how it's turning around in the present day: maths beats physics
Perhaps I should do an optics course at university next semester.
The experiment is very neatly performed. I think it is one of the best videos on the subject I have ever seen.
Light bulb moment for me. Thank you.
Top it lol
I watch it on my pad, but I will rewatch it in HD later. Great video.
But why none shows when detectors are placed in the slits to see where the photon passed, so that the probability function should collapse and lose the interference pattern?
This is what I'm looking for. .I want to see the collapse to one particule on and off
How do you detect a photon without stopping it?
Nobody shows you that because it is boring. It just looks like light passing through one hole, and we already know how that looks like.
@@stalinbeltran4955 Boring? It would be awesome. Turn off the detector and we see interferences, turn on thr detector and we see two lines. It'd blow my mind.
One of the best channels on the subject. Clever and unique
So this made me understand that light is NOT simultaneously a wave and a particle, as sometimes stated, rather it is always a probability function until it is collapsed to a particle. Makes sense.
Not just that but the elementary particles are propagations of energy in their respective fields. A Boson particle is literally the presence of the energy of that specific field and it's very existence is what allows particles to have their mass. In fact that very particle is the glue that binds the other quarks together and acts as the "force carrier" for the other forces. It's what allows the weak force, strong force, gravity and electromagnetic radiation to interact with the particles.
I'd say that nobody doesn't actually know what any elementary particle is and why everything goes the way it does. All we have is set of facts and banch of assumptions. We can't even talk about existence of particle outside measurements. We cannot be sure that wave&particle properties are demonstrated either by particles or its classic characteristics like coordinate. Quantum physics itself can only predict what the probability of particular value in measurement, unfortunately, nothing more.
Sad view but realistic. I consider, it's much better than belief in sumptions
There is no particle-wave duality, there is only waves. Particle theory only confuses people, Quantum Field Theory is the real meat that people should focus on. IMO particle theory shouldn't be taught in schools anymore, it's a waste of time.
Dude that's the heart of QM, most people just aren't willing to accept it.
Imagine floating above the ocean with a blindfold on. You are at an elevation that is at the peak of the wave. Periodically, you feel a force hit you. You say it's a particle because that's what it feels like. It's actually a wave... And the wave is made of smaller particles.
Bearing in mind this analogy, there are waves in quantum fields. They are made of virtual particles that mediate this process, sort of like H20 molecules in our ocean wave, but with infinitesimally small lifetimes.
If you can imagine an ocean of water molecules coalescing into a wave phenomenon, you can imagine a field of quantum virtual particles doing the same.
Particles themselves are force carriers of the field they come from. When fields aren't static, they oscillate and a ripple of that energy propagates through space. This oscillation in a photon is its wavelength, which takes up physical space. Now imagine you take this spring and you confine it to dimensions smaller than the length of the spring. It interferes with itself and offsets the trajectory.
These analogies should be taken with a grain of salt. The real understanding comes from a very deep understanding of math. When you can speak math and in your mind you see physical interactions, then you can build up into the quantum realm and the mathematics is guiding your visualizations. It's all still physics, but you get a clearer picture because you can see what's happening based on the math alone. Since the math is complex, most of us scratch our heads trying to understand what goes on.
Tldr, think of photons as propagating springs. Then imagining how a photon can affect its own trajectory isn't so hard.
That imagery is stunning. Both in information and beauty. Loved the graphs
Please make a video about which way, delayed choice, and delayed choice quantum eraser...
Yes please.
I second that
Way better explanations than any other online site. Good basis material.
This was amazing. Just curious to see what happens to the interference pattern when you "measure" the photon as it goes thru one of the slits. In the typical explanation they always say that the interference pattern can be prevented if the photon is measured at one of the slits. This prevents the self-interference from occurring. Not sure how this would work exactly, though it's commonly espoused in many explanations.
Yes, I'd like to see this too. I haven't found a video yet that shows it.
remember that the photon probability can only go when there's no matter, so you just reconfigured the environment, putting a detector is the same as closing slit. unless somehow you can make a detector with 0 mass, but then by definition it is not a detector, as light can only interfere with itself, not with other sources
@@monad_tcp As a physics idiot, I'd love it if someone could explain to me why the camera doesn't function as a "detector" for this purpose. That's part of what has always baffled me about the description of the double-slit experiment: how does something "know" it has been measured? Why wouldn't the capturing of the state of the photon's waveform on a CMOS count for the collapsing of probability in the quantum realm?
@@VeganAtheistWeirdo I'll try my best to explain it, I'm only studying this as a hobby, I'm a MsC in computing science, not Physics.
First you have to know what a detector is, detector is anything at all with interacts with the system (including the experimenter).
The camera does function as a detector, but there's a difference, on where it is put.
Something doesn't know it was measured, that's the entire point, its the observer who observe different results, because the act of observing changes the experiment, you are not decoupled as an observer.
I like to think that if you put the detector in one of the slits, the detector itself will be entangled into the experiment, so the state of the detector is part of the experiment, and that's what collapses the wave-function (from the point of view of the other "detector", the experimenter).
"Why wouldn't the capturing of the state of the photon's waveform on a CMOS count for the collapsing of probability in the quantum realm?"
But It does do that, that's exactly why if you try to put the detector in one of the slits, it stops the photon from interfering with itself, its now interfering also with the detector.
Which perhaps contrary to what you would think, makes the function collapse, the function won't collapse until its observed, aka, interacts with anything.
Its opposite of what you think, the real mind-blowing is that the result changes depending on where you put the detector, aka, the observer changes the result of the experiment.
But if you put the detector after the double slit, it gets the photon interfering with itself.
If you think in terms of information, the detector when its on one of the slits just have half of the information, the other half is missing.
So the photon will collapse on the detector with 100% of certainty, because you miss the rest of the data of the photon interference, so it looks like it is not interfering, but it still is (you need the entire state of the detector to see it now).
The only way you could observe the photon interfering with itself is if you somehow entangled the entire detector with the experiment, but that's almost impossible to do, detectors are macroscopic objects that pretty much interact with the entire rest of the universe...
Very hard to isolate, as you can do with a couple of particles.
"detectors are macroscopic objects that pretty much interact with the entire rest of the universe..."
I mean, a CMOS camera as a detector.
indeed a single particle would be a detector.
One cool analogy, imagine trying to measure the speed of a car in a road by sending an speeding driver to crash into that car.
That's how detection works, sure you can now know the speed of the car by crashing into it, but you changed the outcome of the experiment, and also lost all the other parameters, you don't know where the car was, only its speed because you knew the speed you sent you car to crash, and how far debree went.
That's why anything at all with interacts with the system will make it collapse.
It only does the quantum "thingy" when no one is looking, aka, no "collisions", no interactions.
Bear in mind that all analogies break at some point, the only thing that always work is the math. Our *monke* brains don't have circuits to deal with it, we have to trust the math.
Perhaps we are doing the cart before the horse, perhaps the universe does compute things lazy evaluated, instead of eagerly like we like our math...
The universe calculates after the fact, the interaction happened, not before, that's why it looks like the probability knows before-hand which path it should go, and that it is obstructed by the detector before even reaching it.
Its not that baffling if you think that way, its just go against common sense, but do remember that time don't pass for photons, so indeed, it can calculate things retroactively in time.
And I only study that because I want to do cool things with quantum computers, all of this is just what I grasped at this moment, and probably is very much wrong, lol.
When someone searches about the double slit experiment, THIS is the video that should appear first.
Has this experiment ever been done in total darkness?
What an excellent demonstration. Especially the figure at 20:30. Thank you for this, it really was mind expanding.
What confuses me is when the wave function "decides" to collapse. The photon interacted with not just the slits, but glass lenses, and gas molecules, but only collapsed on the ccd? Or did it maintain its ambiguity further? All the way to the camera's cpu?
Well, that is a matter of opinion I guess. PersonalIy I would limit the actual observation to the absorption of the photon, otherwise even your mother in law could get involved if she owns the computer. Generation of an entangled pair by a photon also counts as a detection event.
Huygens Optics Haha, you know you're into some esoteric science when opinion becomes a factor ;)
So the photon's wave function travels along, interacting with the slits and glass and air but not getting absorbed until it reaches a ccd cell. Of course many never make it the whole way and are absorbed along the way, thus losing the information about the slits. Does placing the light filter after the slits change the outcome, I wonder.
@@HuygensOptics "Science " demands that you not get entangled with your mother-in-law (even if she owns a computer.) @Aaron Davidson thanks for making the point there is other 'stuff" that a photon "could" be partially absorbed by that "we" don't see (but discrete states prevent that ???). Was wondering about the difference experimentally between vacuum and air. The way I visualize the 'Wavicle" is a sphere or wave-front that has a slight rough -ish texture almost and the matter that finally absorbs the energy of the photon to also have a rough texture; so that wave-front could "ground out" have it's energy collapse at a myriad of different "contacting/interacting " points that are very hard to predict (almost analogous to predicting where lightning might strike / or visually analogous* (crudely and momentarily) to one of those plasma spheres. Really nice explanation of where the wave-front/wavicle/single photon can't go by Huygens Optics / Jerome.
So my next question would be "What's the deal" with really larger molecules and even "macro structures/fluids" that are capable of interfering with itself ? ~ Are they quantum entangled or what's going on there ?
@Jerome I thought you disappeared for a while but seems UA-cam didn't notify me when you made new videos - and now I see you have been super busy ! Veritable treasure trove here ; your videos should have waaaaaaay more views (shrugging shoulders) ~ I like your "ripples video" very three dimensional sense of the interference "structures" in 3d space. Heroic stuff going on here , really awesome.
__________________________________________________________________
* My visual (mental really) analogy could be woefully wrong / contrived / counter indicated by actual 'Science". Thankfully my mother in law is not a quantum physicist... (but she does own a computer - shhhhhhh (tip toeing very quietly on egg shells ).
@@extradimension7356 thanks man. So about the bigger molecules: in principle they all obey Heisenberg, large or small. The only difference is that the effect of the uncertainty in momentum becomes less evident because of their much larger mass. So your experiment will require smaller slits, much closer together.
@@HuygensOptics I'll try it out ~ experimentally almost everything you do is very inspirational - going back to first principals and not taking anything for granted and strangely when you bounce out of that really reminds one there are still many many new types of photonic applications yet to be "Discovered" or put into action in new and useful ways and combinations that may have overlooked. The essence of how it REALLY goes (experimentally ) and the more subtle interactions and finer detail are so important I think . The point you made at the beginning of the video is very well taken. AND with the modern kit available now that can be scrounged / hacked together for not too much $. Incredible.
I need to remark that this is probably the best teaching video series on youtube, just in terms of general internet video pedagogy.
It’s a “wave” that sometimes gets measured as a particle. 😁
Edit: A discrete particle has wave-like properties. Our monkey brains see emergent physical properties. Conceiving a deterministic world takes a small leap but it will make perfect sense.
its both tho
@@forsaturn4629 its just a wave ;) why complicate things?
Would you say a duck in the middle of a lack swimming is EMITTING waves?? No! lmao you would say its causing them :)
so what's causing the "waves" when you turn on a lightbulb?
The bulb is not "emitting" light, its simply causing a phase change in the ether, which manifests as a disturbance that propagates at the rate of induction (which we call the speed of light, erroneously).
“Light cannot be anything else but a longitudinal disturbance in the ether, involving alternate compressions and rarefactions. In other words, light can be nothing else than a sound wave in the ether.” -Nikola Tesla
Things become so much more beautifully simple when you reject the cult of quantum
@@maeton-gaming its both tho
@@forsaturn4629 What is a field then? Modern Atomism and the cult of bumping particles cannot define a field ;) you guys only focus about QUANTIFYNG effects, aka COUNTING, aka MATH - DESCRIPTIVE, but not EXPLICATIVE.
so, thusly, you are simply describing phenomenon - which is why so many of these "weird" things cannot be conventionally explained by Atomism: EPR paradox, spooky action at a distance, quantum tunneling, double slit interference - all of these are DIFFICULT to hold up to the light together under the minds of Atomists, yet it becomes beautifully more simple to explain if you simply start with the premise that the Ether exists as total potentiality (this was what the ether was once called).
Suddenly, the double slit makes sense. Especially if its a wave of ether disturbance making its way towards the two slits at ~300 k/ms ;) The interference phenomena is then properly described using wave mechanics, and we don't have to futz around with particles that don't EXPLAIN the foundations of reality !!!!!
it took me 2 years to break the programming of modern atomism, but if you truly (like I) have this urge to discover the meaning of reality - I will implore to watch this Polymath explain his theories ;)
maybe you too one day can shed the mantle of the Cult of Atomism :) Mother nature does NOT have a bag of magic bumping particles lmao
Light & Magnetism - Deepest Secrets by Ken Wheeler
ua-cam.com/video/dQYkEVFQNDc/v-deo.html
@@maeton-gaming its both tho
A truly wonderful channel. EM radiation has always fascinated me. I have watched a couple of your videos so far and have thoroughly enjoyed your point of view on the matters!
Sir, great experiment. *SINGLE PHOTON* comment, because it is easy math that anyone can understand... With E=hv, the Frequency Term is in units Hertz, which is PER SECOND. Einstein's Photon energy idea is based on 1 second's worth of time, but is being used as INSTANTANEOUS. As you well know, if I had a 1 Ghz processor that would instantly switch on/off 1 billion times, instead of take 1 second, that would be a miracle. So how can Photon Energy be based of Hertz frequency and be instantaneous? OR, if you believe in the instant proportionality idea, then why would the Energy of a Photon be based on 1 second's worth of time? Does nature know how to build things via 1 second? E.g. A Red Photon ~400 Trillion waves occur in 1 second, so why would nature create INSTANT energy based on 1 second's worth of wavelengths? Either way you look at it (instant energy or energy that takes 1 second to build up), Einstein's Photon (or light quantum) can't be correct.
Absolutely write lol
@My OhMy **
If you look at Max Planck's 1901 paper (where it came from), you will see that the value of "h" was derived by 1 seconds worth of Blackbody Power in Watts.
If you claim e=hf is instant energy, then how does nature know to create instant energy photons that have *exactly 1 second's worth of wavelengths?*
**
If the value of a Red photon (for example) *was based on math* that had 1 year's worth of Joule energy, then I guess you would claim that.
When you read Einstein's 1905 Photoelectric paper, he claims light as a particle on emission and absorption events. OK, when does it ever become a wave? What is the process after emission that *transmutes* the photon into a wave that travels through space? If there isn't a mechanism, then light emission as a particle will always stay a particle during transmission until absorption.
So, if you claim light is a particle, then how do you explain the double slit experiment? It is obvious from the Point A (emitter/source) to Point B (receiver/destination) that light is travelling as a wave through space, because of diffraction. It is obvious that light *IS NOT* travelling through space as a particle (because of diffraction).
It is just using common sense, and basic high school algebra to show Einstein's photon fallacy.
Einstein *REQUIRED* the photon idea in order to write the Special Relativity paper, because relative simultaneity absolutely fails with LIGHT WAVES via AETHER MEDIUM. Light WAVES allow you to work with _TIMING/WAVEPERIOD, SPACING/WAVELENGTH_ and _MEDIUM DISTURBANCE ORIGIN,_ instead of just DURATION/SECONDS and SPACE/METERS and OBSERVERS (as in Special Relativity).
**
Just image that the feeling is mutual about Einstein followers. I am trying to show a way out using basic reasoning and logic. It's a take or leave it deal, because I am not doing it for self-promotion.
@My OhMy *
@My OhMy **
I already explained why the sample size is relevant. Do you not understand what a debate is about or is your mind always just correct?
**
You realize that Planck did not take the measurements right? The blackbody data was from supplied Kurlbaum and Rubens, which is what Planck's paper says. I would suggest--google:
Planck "On the Law Of Distribution of Energy in the Normal Spectrum"
In Section 3 - Numerical Values, you can verify.
Most people that "understand" this stuff rarely read the original work and/or research the original history. Science then becomes a canonical doctrine of textbooks and professors.
@My OhMy **
Sounds good... And I will go look on Ebay for a 1 GHz Frequency CPU that processes 1 billion instructions per instant. Maybe Intel has released a new one of those...
You, sir, deserve far more than 10k subscribers
Compared to other videos on this experiment this is much higher quality content then average, Still you cheapen any real derivative from this demonstration by jumping over the most crucial element, Have you isolated a single photon. I would say no
You're right lol, In order to observe single photon(quanta E=hv) of visible wave length 400 nm to 7.50nm you need to turn on and off of your laser or open and close the shutter of your camera 4*10^14 to 7.5*10^14 times per second.
I would say yes, he fired them off so slowly that at every moment most of the time there were 0 photons, while at other moments there was one. Only in 1 in many millions of times would there be 2 or more photons in the air. we did that by putting a very dark filter before the light source. The filter is so dark that it look many minutes to gather enough photons to make a grainy image on a sensitive cooled CMOS.
@@kapytanhook Imagine you had your cmos sensor and photon source in a completely sealed box with no visible light. Photons of many many other frequencies are still present. thermal imaging inside the box would be easy proof, a gamma detector would also. "Photon" is not actually the name of brightness or packet of energy which happen in visible region. Even in darkness you will have also photons but in invisible region, due to the presence of matter at above Absolute Zero
How can you claim single photon self interference when a photon free system currently is not known to exist. Even the most perfect vacuum surrounded by shielding and cooled to the record of the lowest temperature ever achieved in the universe -273.144 degrees Celsius (stunningly close to absolute zero) you still cannot claim you have a photon free system
and without breaking the laws of thermodynamics you never will.
Absolute zero cannot be reached because the temperature of the substance being cooled approaches the temperature of the cooling agent asymptotically, The kinetic energy of the matters ground state cannot be removed and hence neither can its photon emissions. Its paradoxical in a sense that you can never 100% discount the possibility that another photon wasn't involved in the detection event at the physical sensor or that the path of the detected photon was not interacting with other photons before the detection.
Have you Isolated a single photon?
I still say no.
@@aerosoapbreeze264 sure, honestly a very good point, photons of that wavelength maybe but there are trillions of thermal photons. It should be a different pattern though, the patterns are different for different frequencies. The fact that it closely matched shows that that laser's photons aren't affecting each other to cause that interference.
But yeah I don't claim to understand what really causes light to behave this way. I find the idea of it being everywhere at once completely ridiculous, the wave function is a handy calculation tool, nothing more.
@@kapytanhook I Agree, and truly I'm not sure what the truth is but I do think some of the claims about the nature of quantum reality are logic breaking absurdities that I struggle to, or rather cant comprehend.
I'm willing to go as far and claim that if the current list of supposed quantum effects are ultimately true, It's inherently impossible logically understand, A real Metaphysics.
Interesting how the narrator presents the relative simplicity and easy availability of the hardware used, seemingly ignoring the wealth of scientific knowledge necessary to put together these experiments and achieve similar results.
And therein lies the beauty of science; he's right to emphasize that aspect. Knowledge is free for anyone to acquire. You don't need expensive schools or tools. Just time, dedication, imagination.
When I first saw the video title, I said: "Here goes another guy talking about the interesting double slit experiment again", which is quite interesting to me, but I thought I'd hear the classical ideas about it. Yet just a minute after I started I realized this video is totally different from what I have expected and heck, I loved it! Love your Dutch accent as well! It reminds me with my old days hanging around in the world with many Dutch colleagues. Thanks
Nice work! I do believe I understood your explanation, and was able to follow along. However, don't ask me to repeat that!!! Nice to see what you are doing with your machine, how you used it for creating the slits!!
This channel is criminally underrated. Thanks for your contribution to quality optics educational content.
Thank You! Best explanation ever... I've been scratching my head for decades about the photon's "behavior" concerning its position: not scratching anymore. I love all your vids. Thank you again.😁
I only recently discovered your channel and I am truly facinated. Absolutely great work. Many thanks for sharing all your experience and knowledge.
It doesn't get better than finding a rabbit hole being shown experimentally. Well done good sir!
Thank you for shedding (and spreading) some light on this
I understand virtually none of this and probably never will. I just wanted to say that your graphics were stunningly well done. Fascinating.
Many hidden gems on UA-cam -> this channel keeps on giving.
I have to agree with the comment below...this was the BEST explanation that I have come across so far. I particularly learned how to explain how a SINGLE photon can travel through BOTH slits to create an interference pattern. MOre precicely, a photon's wave function travels in ALL directions at the same time *mind. blown* What I would want, is an explanation in THIS amount of detail of the quantum-eraser double-slit experiments.
You are right. I have heard so much yet have never seen the actual experiment. Now I have seen it. Its nice to see it done for real.
This needs to be explained at this level but over a series of videos 10+ hours to be able to really dive in to de details of measurement and the effects of observers.
Practical explanation gave me indepth into how mysterious .....quantum mechanics is.....
I never heard better explanation / experimental illustration that leaves no gaps for "magic" in a quantum phenomenon. Absolutely brilliant truly scientific explanation! This should be in text books everywhere!
Great video and an awesome demonstration of this experiment (which only just popped up in my YT feed) ! What I always point out to people is that the probability distribution does NOT mean the particle/photon has a definite position that we merely don't know about. What it means is the particle really DOES NOT HAVE a singular position until there is an interaction with something else.
Also, it would be really cool if you could demonstrate the delayed choice quantum eraser experiment, which is even more mind-blowing.
Perhaps the best video on YDSE available on the internet. Thank you so much!
I have done this double slit experiment when I was in high school. It was in our physics study syllabus. At that time I didn't know the importance of this experiment. Now, after about 15 years later I realized that this experiment is one of the very important phenomenon in quantum physics.
Well explained. Also leading on from this it explains why the speed of light is slower in materials than through the vacuum, because the photons have more possible paths to travel.