This is literally the only thing I've seen or read that actually defined what "measurement" means with regards, to the double-slit experiment. Such an important thing and nobody ever bothers explaining it - except you!
Karen Barad's book Meeting the Universe Halfway has a more in-depth explanation that might also be helpful. She also talks about the history of the double slit experiment, and its importance in philosophy.
Why is a detecter considered a recording but seeing it and processing it with our brains not? If our eyes could see the path of electrons would that be enough to make a difference?
@@unsignedmusic Yes, I think so. He didn't say that seeing it isn't a measurement, he said that it is not necessary to see it. Because usually one (including me) would think that a human or animal mind is needed.
Damn man! This is all inclusive. 1. It gives one of the best double slit experiment explanations, like ever. 2. Easily deals with the myth of the conscious observer. 3. Answers the main question very well.
The problem is the definitions of information and observation are ill defined. Invoking some kind of quantum akashic record doesn't get rid of consciousness.
The use of the words “observation” and “measurement” in quantum mechanics is thoroughly misleading. Replace them by “interaction” and things become much clearer. A probability wave exists only while it’s _not interacting._ When an interaction takes place it collapses. An interaction is an _exchange of information._ Nice video - intuitively appealing and convincing.
If it acts like a wave it’s a wave...same as photons. The waves collapse directly because of the detectors. Therefore you get a single position just like any other particle or macro object. What the field is and how it interacts with spacetime (unknown fabric they speak of) is yet to be discovered. Perhaps the microscopic particles, which are pure energy, cause ripples in the fabric?
Right, but thats not the whole picture. To be more precisely you should also say "when an interaction took place, takes place or WILL take place", and this is where it gets so mind-boggling.
This really sounds like a way a developer would optimize his code in a universe simulation (if no record is being made, then use the standard wave behavior) that is crazy to think about
I was thinking the exact same thing! I'm surprised someone else thought the same thing. The weird thing is that there are many observations about our universe which could possibly be explained by thinking of the universe as the equivalent of a computer simulation. But the double slit experiment is an example where the simulation analogy is the ONLY way it makes any sense (at least in my mind).
Exactly, his explanation on observation and measurement in a previous video was great and easy to understand for people like me, who really have little to no clue what any of this means lol
My closest guess of why this is, is that every probability wave plays out on a field. You can't measure something on that field, without putting something else into that field to measure. The moment you do so, you change the shape of the field. Which changes the probabilistic outcome of deterministic processes that occur within that field.
Amazing. I love how you approached this. I gained a unique perspective on quantum behaviour that i didnt get from any other attempt at this topic. Nice one!
@@DAG_42 False statements? Like what? And why do you know better? We'd like to hear an actual explanation. And it's not because I want to challenge you, but because I want to know how it actually works if it doesn't work like this. If you know better, share it please.
This is priceless content. Maybe this speaks to my stupidity but this is the only channel where I don't have to sort out confusion born out of the content I'm watching. Your videos make me feel like I moved slightly forward and leave me asking new questions. Thanks always!
Ive watched 6 or 7 videos explaining the double slit experiment. I happened to click on this one just for kicks to see if I missed anything. Im glad I did, the clarity of your explanation about information made many things click for me.
This might just be me, but I've NEVER heard someone give such a solid, succinct, and easy to grasp explanation for the whole "what could potentially be a measurement in quantum physics" thing. I've always kind of struggled to understand it before, but your explanation, combined with the examples about how hard it would be to -not- measure something like a tennis ball, made it all click for me. Thank you!
In order to "measure" the photons passing through the double slit experiment, wouldn't that entail some sort of physical external interaction with the photon? It makes much more sense that this action would materialize the wave function into a concrete phenomena as you've effective imparted external influence on it. I think a lot of people are thrown off by the use of the term "measurement"
@@ArvinAsh If that is indeed true, then calling it a measurement is simply misleading. I've seen a double slit experiment with a polarizer as the "measurement" object. But a polarizer forces the particle into a specific state, but doesn't tell you it's state before it went through. Ofc that can erase the interference pattern!!!!!!!!!!!!! I think, I finally found the puzzle piece that was missing in this double slit experiment. It's that the media omits crucial information to make physics sound like something mystical. Aaah, this is SO disappointing...
This is exactly the problem I have always had with the terms "observation" and "measurement". Both terms imply a passive approach. There is no such thing as "passive" measurement in QM. And since by measuring, you actively interact with the photons, you collapse their probability wave into quantum states. Where is the mystery? At this point, I suspect physicists conciously don't clear this up to keep up the state of mysticism :)
NOW I understand why making a quantum computer is so hard - the superposition collapses from an event as trivial as the emittance of some blackbody radiation (which explains the extreme cooling).
The blackbody radiation isn't a problem as long as you make sure it isn't measured in a way that allows you to reconstruct the path even in principle - see the concept of a quantum eraser.
The best discussion of the double-slit experiment I've ever seen! I'd love to see you go into more detail as to why small-scale objects are more informationally isolated than macro objects. It's one of those "seems obvious' things, but it seems to be at the heart of the measurement problem. Could atoms have their wave function "chipped away" instead of collapsed in one fell swoop like photons? How long can "large" things like molecules stay isolated, and under what circumstances?
If you make the measurement intentionally faulty, so that it fails say 25% of the time, then the collapse of the interference pattern may not be total. Look up quantum decoherence.
In an experiment done in 2019, molecules with masses greater than 25,000 atomic mass units, remained in a superposition for more than 7 ms The wavelength though becomes smaller as the mass grows. So the interferometer you'll need becomes bigger. To detect the wavelength of one thousand times smaller than a hydrogen atom they've built an interferometer with a baseline of 2 meters long. As I understand it, that would mean that it's possible that if isolated, macro objects behave very much like waves. It's just that you wouldn't notice it since the wavelength is infinitely small
correct, weak measurements of the position can be made to keep most of the interference while gaining information on where the particle or photon is generally at or it's speed and direction, this was done in the area between the double slit and detector, and was used to create a map of the paths photons tend to take between the double slit and the detector. the result was similar to the path models that de broglie-bohm/pilot wave model predicts.
Question: your argument about "theoretical" possibility of always determining the path of tennis ball, works the same for particles, no? Particles have gravity, photons interact with them, and so on. So it is also impossible to isolate them in theory. What am I not understanding? Thank you.
Danuta Galecka I have the same question. I feel like looking at it with the Copenhagen interpretation is incomplete as he said that the wave interference still comes up with molecules for 2000+ atoms. Surely these interact with photons around them, have a gravitational pull and also (I would think) have some kind of blackbody radiation.
The thing is that particles are always where the probability wave is high, the higher the wave the higher the probability that the certain particle will be there once you measure it, there is a principle called the uncertainty principle, the uncertainty principle says that you can't know the exact position and momentum at the same time, you either can know it's position but not momentum or vice versa. The quantum world is very very different from our classical view of physics. You can't know the path of a particle cause it doesn't have a path, it's anywhere where the probability wave is high
By looking at heisenberg’s uncertainty principle, it can be seen that the more is known about the momentum of a particle, the less is known about its location, and visa versa. Basically, imagine that you draw a line on a piece of paper that represents the path of a particle over time, you know it’s direction, but you don’t know where the particle is on that line. Now, if you drew a dot representing the particle at a certain time, you know it’s location, but have no information about its momentum. It’s an interesting theory and can bring to light the reasoning of a lot of other parts of quantum mechanics.
Danuta Galecka particles can act with the properties of waves, calculated by using de Broglie wavelength calculation, meaning at that it would not be affected by fields such as gravity, etc. However, tennis balls are so large that for it to have the properties of a wave it would have to move so incredibly slowly it would be staying perfectly still. Otherwise, it’s wavelength moving at 50 m/s, or a tennis serve speed, would be smaller than a Planck length, so meaningless.
I agree that this is still an issue. Under this definition of informationally isolated, I wouldn't expect electrons to exhibit wave behavior in a double slit experiment. I don't see how the uncertainty principle addresses this at all. Regardless of the de Broglie wavelength, there would be gravitational information encoded in the path. I also suspect this is an issue with the Copenhagen interpretation and the (in my opinion dubious) link between information isolation and wave function "collapse"
Was dying to know the answer about the behavior of macro objects ever since I learned about the dual nature of quantum particles. Thank you arvin 🙏 love your videos. You and PBS Spacetime are the best UA-cam channels 👍
The true mark of a master is one who can explain to non domain experts complex or abstract ideas without using the terms and nomenclature of the experts’ domain
Absolutely love your quantum videos, especially in the way that you are able to explain difficult-to-grasp concepts so eloquently and clearly while also touching on the beauty and mystery of the quantum world
This was a really clever and original topic for a video. I watch a lot of science video's this is the first time I've seen this topic. I have always wondered the answer to this question but honestly I didn't think there was an answer or that anyone would really understand the question. Now I know! This channel is the best.
Finally someone said in simple words what I have been thinking for 10 years of what "observation" means. All physicist use this term in popular science entertainment all the time, but nobody ever bothers explaining it. And I've never before heard about the wavelengths of macro objects in superposition approaching a point. This is such a simple explanation, but somehow nobody felt the need to ever mention that.
It doesn't make a difference seeing that a record is only a record if it is (in principal) interpretable. Records are just detours along the way to concious observation.
While watching this video, I started getting frustrated thinking about the definition of observer, a thing in many quantum mechanics explanations that gets skipped over. But then you go and provide the easiest to understand definition I've seen yet! It was really useful to be able to actually understand the importance and implications of information isolation.
Its like being trapped in a Truman show with everything surrounding us in synchronized conspiracy to keep us from finding out that we are the ones being watched.
It would certainly be a handy bit of code if you're running a complex simulation and want to ensure that nothing interferes with the progress. Like a firewall built into the basic code of the program to prevent external information from corrupting the data you're trying to collect.
I'm pretty sure we're on TV As Above So Below. You know those characters on the TV show that their self aware that there in a computer and they want to get out. I'm pretty sure we're all agent Smith. But I'm also pretty sure we're all Neo. But I'm also pretty sure there's a Main. And a judgment. But I feel like someone needs to be sacrificed. I legit saw that s*** and then I'm the one that gets called schizophrenic. I ain't man enough.
Thank you! Finally, someone gets the dead/alive cat scenario right. I get so tired of people saying that 'the cat in the box is alive and dead', because they don't understand what a paradox is. It's very refreshing to have this explained properly.
@@stivendog Not quite, "sound" is what we call a pressure wave in a medium. Ear receives and brain interprets but the sound (aka the pressure wave) still exist without ear and brain.
@@yoooyoyooo There are no 'photons', light is waves at all frequencies, there are no particles. It is a thought-experiment, the "photon detector" is an imaginary mathematical probability idea, not a real device. It is impossible to passively tag a wave (or a particle if you prefer) with an identity as it passes through the slit, the only way to detect a wave is to put physical matter in the path which consumes the wave energy by absorption so obviously nothing would come out of that slit. It's the same wave which goes through both slits and causes interference from two separate slit sources on the other side. The interference experiments do not have any detector because that would block the wave and cancel the interference, that's why NONE of the interference demonstrations have detectors, that's why you are only ever shown graphic cartoons of detectors collapsing the wave functions from slits.
@@yoooyoyooo There is no wave/particle duality. Physicists had developed a system for analyzing waves, so they applied their wave-system to matter by treating matter as waves, then followed the converse proposition by treating waves as matter. The wave/particle duality is merely the nonsense of misapplied system analysis. Electromagnetic radiation (EMR) is waves at all frequencies, never particles. Every experiment shows light is waves, there are no EMR particles, there is no duality. What they call "single photons" is a high frequency interrupter relay transmitter switch used to produce single separate individual wavelengths, like this ~ ~ ~ ~ ~ not "photon particles". Continuous waves produce interference patterns and intermittent separate single waves also produce interference but at a slower rate/intensity because of the gaps between waves. The interference is the proof that light is waves at all frequencies, never particles. "Probability waves" only exist in researchers imagination, that's why nobody (including de Broglie) could design an experiment which shows light is particles. The photoelectric effect is easily explained by blue light having the right frequency of positive/negative magnetic induction (alternating push/pull) to magnetically agitate a negatively charged election out of it's shell orbit, that's why the photoelectric effect does not work at higher or lower frequencies - nothing to do with "particles". Did you believe red light was waves but blue light magically manifested 'particles' which disappeared again at higher frequencies. Electromagnetic Radiation (EMR) is waves at all frequencies, all the experiments show light is waves, there is no experiment which shows light is 'particles'. The "photon detector" is an imaginary mathematical idea, not a real device. It is impossible to passively tag a wave (or a particle if you prefer) with an identity as it passes through the slit, the only way to detect a wave is to put physical matter in the path which consumes the wave energy by absorption so obviously nothing would come out of that slit. It's the same wave which goes through both slits and causes interference from two separate slit sources on the other side. The interference experiments do not have any detector because that would block the wave and cancel the interference, that's why NONE of the interference demonstrations have detectors. There are hundreds of videos showing the actual double slit interference but none showing the actual wave function collapse as the interference pattern disappears into observed "particles" because it's only a thought-experiment. Quantum electrodynamics textbooks give a summary of the discussions between Bohr and Einstein in which they each propose a variety of impossible imaginary "detectors". They were just talking, the 'detector' was just an idea. Physics had a well-developed analysis of waves, so as a thought experiment they started treating matter as waves, later they reversed the thought experiment and started treating waves as matter, the self-induced paradox of the two thought experiments created wave particle duality and 'spin' only exists in the minds of believers, not in reality. Schrodinger published his cat in a box thought experiment only to demonstrate the absurdity of the wave/particle duality idea, Schrodinger was later very surprised to see his absurd cat in a box story being used to demonstrate the true nature of state vector collapse wave/particle duality. Relativity and Quantum Electrodynamics are thought experiments, that's why cosmology and QM are a cult-like belief system with a priesthood guarding their made-up doctrine by excommunicating doubters, for example, it is impossible to have academic career in physics if you say there is no proof that black holes exist. There are some places in the universe which seem to have more gravity than expected and some of these places seem to have more gamma radiation than expected, that's all we know about "blackholes", everything else is speculation, but if you publicly say this you become an outcast without any academic employment prospects. Go and search for actual experimental evidence of wave/particle duality and you won't find it, because it does not exist. Electromagnetic Radiation (EMR) is waves at all frequencies, never particles. You must have suspected this surely?
One question: Photons are affected by gravity and therefore give information about their position. This means i can essentially revert your question: why doesn't a tennis ball act like a photon to: why don't photons behave like a tennis ball if they give information?
Exactly what I was thinking! Bravo! Similarly, the light emitted from the monochromatic light source is an electromagnetic wave so it interacts with magnetic and electrical fields, so in the laboratory it must exchange information with the universe via the fields present there. So why is that light not exchange information with the universe.
@@XEinstein My guess is, that this interaction is too week as that the "information gain" it contributes gets wiped away by the Heisenberg Uncertenty Principle. Edit: Also after rethinking. The slits in the double slit experiment have a finite but non-zero width. Some photons/electrons may get "smahed" against the border of the slit and thus have to present through which slit they go (same for photons/electrons which interact with eg an oxygen molecule from air before the slit), but for the majority the deviation is much to low. They still are not forced to go through one slit and present which slit that would be. There is plenty of space in the slit to allow for small devitions left and right. So in a nutshell: the width of the slit insures that small deviations do not force the particle to present the path information.
I have a few thoughts about this video: - it's fantastic - thank you for putting it on! - If small objects are "informationally isolated", that prevents time travel. Theoretically, if we knew the position and velocity of every particle in the universe we could determine where every atom was a millisecond ago, a second ago, a day ago, and as far back as we want. And the same thing would happen to time travel travel to the future. If we had complete information about every particle in the universe we could determine where that particle would be a millisecond from now, etc. How disappointing. As if Heisenberg's "uncertainty" was not enough, the universe puts a second lock on the door to time travel. - I have a different idea than the one given here about why firing photons one at a time still gives a wave pattern. The wave does NOT collapse. (what a silly idea). The universe is not a giant empty room just waiting for photons to come flying through. According to another video in the series (I already learned from this video series! Thanks!) the universe is a container with 17 fields running through every part of it. (ok, it's not really a container lol).. Therefore, we are not firing a photon particle in an empty shooting gallery. We are sending a PROTON WAVE through a room filled with fields. Whether we fire one or many photons makes no difference. What I think is happening is that the PROTON FIELD "bumps into" the other fields that make up the universe. THAT is what causes the interference pattern. The photon is not interfering with itself (another silly idea). It is simply interacting with the background fields which are the fabric of our universe. - The only reason I was able to make a statement about the universe and Fields is because this lecture series is so wonderful. Well, professor, how did I do? I am a retired NASA engineer, and I did not get deep into physics in my work or schooling. I find these lectures fascinating, even if their content is elementary to every child on K-Pax lol. (reference to a movie with that title).
What I think is happening is that the photon is never a wave. It is a particle that only is located somewhere when it interacts. The wave part is the probability of where it will be if it interacts. The probability wave interacts with itself, causing the interference pattern
@@Limbaugh_ It does though. Note that I said "It is a particle that only is located somewhere when it interacts", as in it chooses where it is at random the moment it has to interact
Great explanation about where and why the “cutoff” is. It’s a question that’s been lurking around my mind for a while - at what point does quantum behaviour cease. Thanks.
Quantum mechanics is probabilistic, so you can calculate the number of atoms required for a probability measurement greater than something like .99999999 (imagine even a .0000001% chance of quantum behavior for a tennis ball.... I think it's much lower for our macroscopic objects). I'm not sure the exact cutoff, but it's possible to calculate. The reason quantum behavior disappears with macroscopic objects is due to the degrees of freedom decreasing with increasing number of particles. Maybe think of sand verse a large rock - the rock is rigid, and the internal behavior is very constrained. Sand, however, is able to shift and flow around. It has much more degrees of freedom than an atom inside the rock. When we think of quantum particles, they lose degrees of freedom as they form together. The less degrees of freedom, the more information that can be determined by measurement. The number of particles required to return a probability of a measurement greater than .999999999...... is when quantum behaviour stops.
nick I never understood how ppl on yt can create comments like these, obviously well known on the topic of quantum mechanics, but can’t help to wonder if the person typing is a professional in the field, or an average joe like me who’s a lot smarter than I am.
@@saltycatagenda I like the sand/rock analogy. Another one I like is the number of times to flip a quarter and record its number of heads and tails. We know it has a theoretical 50% probability of getting heads. And the more we flip, the closer we'll get our experimental value to be exactly 50%. So if we flip a quarter 1 trillion times, it's like an object gaining 1 trillion particles, it becomes certain to be 50% with high certainty, in other words, the object loses its wave function or probabilistic property to become a discrete unit of the macro world. The cut off is the entrance/exit between microverse and macroverse.
Bryan so in the end there isn't even a real exact cut-off so much as the end result being so extremely consistent to a certain degree that the stranger possibilities have negligible impact. And the opposite being in the result being far too uncertain that you're stuck looking at a wave function with missing details no matter how hard you try.
I'm a not scientist nor a physicist, I have a basic school physics education from 55 years ago, which never covered atomic physics as it was called then. However, over the years, I have always been intrigued by the weirdness of the double slit results and the conclusion that followed from them, which formed the foundational explanation of the behaviour of light and quantum particles as understood now as quantum mechanics. I have watched many videos on just this topic and formulated my own hypotheses which can explain all the results, including; the measurement observer problem, particle/wave duality, all without any weirdness, like waves and particles transmuting in to each other depending on if they are being observed or not. I found your video very interesting and used your video expanation to test my hypotheses and I can explain all your results perfectly simply, using my hypotheses without any weirdness. Because you are a physicist, I would love to discuss this hypotheses with you and for you to try your best to break it. I don't think my hypotheses changes the maths around QM, however it could give physicist a new way to look at things and like all good hypotheses, it makes predictions about things we do not yet know, which people like yourself can do the experiments to confirm if the hypotheses to be true or not. Sorry for rambling on so long, thank you for your videos, very enjoyable!
This is the most visually digestible explanation of quantum effect I have yet seen. It greatly helped me to understand a little bit better the dichotomy between macro physics and micro physics. In some ways it reminds me of the philosopher George Berkeley's question, if a tree falls in the forest and nobody hears it, does it still make a sound? I presume we can never take a measurement without interfering with a particle. We believe this interference (interaction?) changes the observable behavior of the particle. If we could take a measurement without interfering with a particle, would its behavior still change, or would it not change? Does the act of measurement, even passive measurement (if such a thing were possible), create a false perception of the event, or does it create a new event (in which case it isn't false)? In the macro-universe we see no observable discrepancies because the joining together of enough particles permanently alters the behavior of these particles. I find this idea comparable to the Gestalt psychologists' famous dictum that the whole is greater than the mere sum of its parts. The joining of enough particles changes the dynamics of those particles in a way not possible when the particles remain far enough apart (what constitutes far enough?). In effect, we are talking about two different universes, one completely joined, and the other completely disjoined (one might say unhinged). Can this latter universe even exist outside of the laboratory?
"If we could take a measurement without interfering with a particle, would its behavior still change, or would it not change?" we can get close, weak measurements have been made before, slightly disturbing the interference pattern, while giving slight information
just a sidenote, while it is true the copenhagen interpretation is the most accepted, it is not accepted by a majority of scientists. I find it fascinating we have all theese well tested results and can't make heads or tails of what they actually mean
@@Amani_Rose Due to the Bell's theorem, either hidden variables are correct or quantum theory is correct, but not both at the same time. Experiments with separated entangled particles have been made, dismissing determinism.
Wow. I've been watching loads of physics vids recently. PBS space time, Fermi lab, Up and Atom... This is the first time I've fully understood something! Mind you, I am a little bit stoned, so perhaps that helped.
Arvin Ash, thank you. This is easily one of the best and most technically correct explanations I’ve seen of why it is so hard to keep large objects quantum. Far too many “easy” explanations focus solely on the wavelength issue and neglect the critical impact of just one atom or photon. Well done! I must also apologize. I’ve ignored your channel for years due to an incorrect impression - I don’t recall from where - that yours was one of the everything-is-mystical channels. That was wrong, and I am sorry I did not check back sooner.
This is hands down the best explanation about the DS-experiment that I have seen. I especially like this "informationally isolated"-concept which allows me to understand the phenomenon just a little bit more which has not happened for a long time despite watching a lot of DSE-videos. It's almost an insult that you don't have millions of subs already.
He didn’t say that. Maybe the answer is that an individual large molecule’s forces enough to keep other individuals far away because of distances between them so big when comparison to their size unlike big object’s.
I think it implies that a large proportion (probably not all tho) of those large molecules in the experiment do indeed 'sneak' through without any interactions, avoiding pretty much all other particles in their way and not absorbing any meaningful quantities of photons. Since some proportion of them does interact, you could probably see and measure some deviation in the results when compared to smaller particles, maybe a more muddied interference pattern. Also, maybe they did freeze and vacuum everything, whereas for tennis balls you'd need some seriously larger effort to do so. All this is just a guess on my part tho
yeah, because gravity goes on infinitely, even one atom has gravity, even if it's extremely small, so it is interacting with everything around it. What's the cut off where it matters? Is it the point where it makes another object move a plank length?
Why was this not at the top of the search results for double-slit. YT and google need to employ people to work this out for such important topics. They can surely afford it and it would advance science. The algorithm alone does not work! Finally, I came to a very good video. Thanks!
I'm a complete physics layman. But *three years ago,* in a science discussion post on reddít, I first noticed and pointed out the convergence of wave-like behavior of atoms into classic macro particle behavior when the relative wavelength becomes super-tiny. I was *laughed at* for suggesting something that silly... so now I feel vindicated -- thank you!
I finally realized that any measurement is the interaction of the device and the measured object. And the interaction isn't something ephemeral, it's a particle/wave. So we measure the data of the particle/wave that carries information about our studied object. Moreover, the presence of a measuring device is not necessary, it is enough that there is an object in the universe basing on which parameters we can calculate some data of our studying object.
No, the presence of a measuring device is exactly why the "collapse" occurs. You cannot "measure" something without affecting it and at the atomic scale any kind of such measurement is going to affect the particle. In short it isn't about the "information" or "superpositions" or whatver, but the experiment itself being impossible to conduct at the fundamental level. It's like saying that a ball isn't flying in a straight line, because you hit it with another ball to "measure" how fast it's going. Of course it ain't going to land in the same spot as if it wasn't hit, so what exactly is this experiment proving? Certainly nothing about quantum physics.
It will to some degree. This is why these experiments are difficult to carry out - it is difficult to isolate larger atomic structures. I am not sure of the experimental setup, but it would need to be isolated. If there are enough molecules fired to the slit, then there may be enough molecules to get the appropriate patterns even if a portion of the molecules get "measured" on the way to the slit. This will just result is some fuzziness of the patterns which are part of the error.
@@AnonymOus-ss9jj it's not about isolating particles from gravity. He never said that. The concern about gravity was that it can attract smaller particles to the one being put through the experiment. The truth is we've never created a true void. With smaller particles they can slip through spaces between the few particles in a void more easily without gravity pulling them to it. With a tennis ball, our current voids cannot realistically prevent a chamber from having enough particles left that the tennis ball wouldn't hit at least one on its way. And if it would miraculously miss any tiny particles, it doesn't once you factor in gravity to attract those particles to the ball, making collision unavoidable.
Hm, I knew the physical size of wave function's "total most probable" area of macro objects is extremely tiny, but I never thought about "information isolation" part. Of course, it's totally correct: any contact AKA "measurement" collapses the wave function. But to think of it, we can't make these "informationally isolated" because macro objects are defined by mutual interaction of their particles: they are more bound together than they are bound with outside world (otherise it's not a single macro object but a collection of objects). And any interaction will collapse the wavefunction of particles or atoms interacted upon (thus, any chemical bond or gravitational interaction will fix the positions of several atoms). The only place where non-fixed particles can be found is deep inside atoms where they are not directly acted upon.
5:36 Hold on, isn't the whole point of the Delayed Choice Quantum Eraser experiment that when you scramble the information about which slit the photon travelled through the interference pattern still occurs?
@@flawmore Yeah I noticed actually.. so he was a bit off when he said the interference pattern is lost forever. As long as we do not entangle ourself with the which-path information the interfence can be recovered.
the universe has already recorded which path was taken before the hard drive was destroyed, in the quantum eraser experiment the path was never recorded 'by the universe'.
I seen so many dbl slit experiment and read up on it and also watched allot of videos and read books on quantum mechanics and the behavior of subatomic particles and this is the best video to describe why macroscopic objects don't behave the way microscopic objects in the quantum level.. thank you so much for this video.. really enjoyed it and love your channel.. thank you again sir
Arvin is easily the best science explainer around these days, this is the first time I've been able to grasp this concept after trying to understand it for over a decade now. Please don't ever stop teaching, you are the best! Whinge: Even though i'm subscribed, YT didn't recommend this video to me, I had to click on your channel to see if you had uploaded anything recently, meanwhile I get bombarded with videos from dumb reaction channels every day that I'm not even subscribed to!!
It's interesting that the go-to example for this is tennis balls. In my Intro Physics textbook, the section on Quantum Mechanics does the same calculation of the De Broglie wavelength of a tennis ball and shows how its quantum behavior is entirely negligible, even if you were to work out a way to not have the wave function of the entire object collapse from interaction with its environment. I've also seen the supposed diffraction pattern for molecules consisting of several dozen atoms, and it's barely discernible from a Gaussian. There's only a very slight dip in the probability off the center of the peak before it returns to the normally expected Gaussian.
One way to interpret the Quantum Eraser Effect, is to imagine reality being recorded in 2 ways in the past, one way as particles, the other way as waves. When our "listening device" is set to measure particles, that is what we record in the future; and when our listening device is set to measure waves, that is what we also record in the future. The Quantum Eraser Experiment is a rather prosaic experiment: it is only showing that reality is recorded in 2 separate forms and that you can observe those recordings in 2 separate forms in the future. IT DOES NOT PROVE THAT WE INFLUENCE THE PAST WITH CURRENT OBSERVATION.
I've seen a couple videos on this topic, but it's the only video that helped me understand, why observing the particle changes its behaviour. Thank you very much
its because when you make the measurement, you are forcing yourself into a very specific quantum btranch of reality. And until you are in that specific branch, all possibilities exist, as literally everything that possibly can happen is happening in the Universe.
This was the best explanation I ever seen on the double slit. It’s weird to think how even our thoughts are connected to everything. Great vid Arvin, 👍
I think I'm fundamentally missing something with the whole double-slit experiment. Isn't it just that the act of measurement breaks the symmetry of the previously cancelling wave-forms, resulting in the collapse? What confuses me is why would this be unexpected? What you're left with is the difference, like with/without noise cancellation? As for restoring it, or eraser experiments, isn't that just moving the shapes back into alignment for them to once again reconcile/cancel? Side note, I would guess it breaks down about halfway between measurement apparatus and the target, as what you're actually disrupting is the chain of probabilities between? But truly I can't imagine a way to know, not until someone figures out a way to assess probability without interacting with it. It would take a perfect reproduction of the conditions to test independently, I think, and there is literally no such thing possible, because "conditions" are not the lab, they're the universe. GG, physics, you win this round. Also, I wonder if it isn't short-sighted of us to assume we're seeing everything happening that can be seen. What we perceive as nothingness (and not just in this context of this particular experiment) could just be forms of matter and antimatter cancelling out within the window of a single unit of Planck time. At that point all we can do is catch a glimpse of it. We can't see it starting and ending. I figure, the best we can hope for is that it'll overlap on a frame boundary and we can see part of its life in that ultra-brief glimpse we're afforded, and maybe, we could stitch together enough of those overlaps to see a more complete picture? Isn't that basically what they're doing with the LHC? Trying to creature enough of these sub-Planck-duration particles so as to catch one or two of them at the boundary? Lastly, I'm happy to be wrong on absolutely all of this and be pointed towards additional awesome videos. Cheers.
THANK YOU! This has also been confusing me for years, ever since I first became interested in physics. No matter where I research I can't even find a conversation about how the act of measurement could be interfering with the results. Glad I'm not the only one who is confused about that side of it lmao
I realize it's tied up with Copenhagen, but I think it's pretty clear that information coupling with the universe is not a binary thing. When we send electrons or molecules through they are definitely coupling with their surroundings through gravity and electromagnetism, but the coupling is too weak to destroy the interference pattern. In order to make a measurement we need stronger coupling. I think there is a range between the interference pattern being pure and destroyed. And actually it may be more accurate to say that macroscopic objects do have superstition and interference patterns, they are just impossible to measure, as you even say.
If such an orbit was stable, it might require negative energy. To put it another way, because it doesn't have negative energy, that orbit is not stable.
@@erurevir if you have the same recording device, but dont have it output its resuly (so its basically just there), interference happens as normal. It only happens when it is actually measured
@@ichmag11 This contradicts what the video said: information is considered to have been recorded even if some infinitesimal particles collided with it and no measurement device made any attempt to track the information about the collision. Because regardless, that particle now has the information, so it has been measured.
@@erurevir You got it right. I think this video is a bit confusing: any particle has a probability wave function that assigns the odd as to where the particle will end up on the screen. When the particle interacts with something, the wave function changes accordingly. When you put a detector as you guessed you make the particle interact with something and so the wave function gets messed up and the interference pattern disappears. The degree at which the wave function changes depends on how strong the interaction is, so for electrons unless you bombard them with photons to get their position, they will more ore less retain the same wave function and generate the interference pattern. Baseballs interact a lot with everything, so it's impossible to make them interfere (not to mention that 2 baseballs are never identical, so they'll inherently have different wave functions, plus the de broglie wavelength as mentioned is tiny)
Detector observed the results that atoms put on the board. Can't really say in which slit the atom travelled through. Probabilities can only be guessed.
I don't think it's accurate to say that the wave only collapses when it is _measured_ but when it interacts with another object. Our presence or knowledge does not have any influence on quantum behaviour, it is the interaction with the particle which is inherent in an act of measurement.
It is a semantics problem, in a sense it is measured if it interacts with anything. Observed isn't completely correct either. Interacting might indeed be the closest English word we have to describe that behaviour.
Please do a video on Schrodinger's Suicide Machine - that is, any scientist who truly believes that the cat is both dead and alive would get in the box with the cat, in the belief that he would emerge in the timeline with the alive cat.
Schrodinger should have suggested a bomb instead of poison. Then he coulda argued the cat cant be alive and dead at the same time, bcus the box cant explode and not explode at the same time. Either that cat is blown up, or he's not blown up and we can verify that by looking at the box from outside. There is no superposition. That is a ridiculous interpretation for them to think this could be a physical reality.
Excellent explanation!!! Finally understood properly after years of reading about this. One question though: How are photons (or molecules up to 800 atoms) isolated from the rest of the universe if light itself is affected by gravity? And those molecules must exert some gravitational effect, however tiny?
Now I’m just thinking out loud but, maybe they don’t have to be isolated from gravity since that doesn’t necessarily make or record any information. If gravity bends space, then you can imagine it like the particles traveling in a straight spacial line that would be observed by us as curved.
Wow... I mean... Really... Wooooow. Does this guy realize how seldom is anyone explained what observation even is? This is one of the most useful movies I have ever seen!
Has anybody actually done the experiment with tennis balls? I've been pondering this since I learnt of the double slit experiment (it was 1998!) I've been designing the tennis ball version in my mind for 20 years.
@@ArvinAsh Pretty easy are you joking? You need a coherent flux of tennis balls , meaning all the atoms of the ball have to get in coherent superposition (technically the statistical density matrix should be almost diagonal) and is not only matter of cooling.
Experiments have been done with Fullerene atoms (60atoms balls) and probably with virus sized particles. In addition Bose Einstein condensates of 20000 atoms show quantum interference.
This is literally the only thing I've seen or read that actually defined what "measurement" means with regards, to the double-slit experiment. Such an important thing and nobody ever bothers explaining it - except you!
Karen Barad's book Meeting the Universe Halfway has a more in-depth explanation that might also be helpful. She also talks about the history of the double slit experiment, and its importance in philosophy.
Yes exactly how I felt. Arvin always nails this. He addresses the most natural questions that most people would ask when learning about this subject.
@The man in the mask Can you recommend some other?
Why is a detecter considered a recording but seeing it and processing it with our brains not? If our eyes could see the path of electrons would that be enough to make a difference?
@@unsignedmusic Yes, I think so. He didn't say that seeing it isn't a measurement, he said that it is not necessary to see it.
Because usually one (including me) would think that a human or animal mind is needed.
Damn man! This is all inclusive.
1. It gives one of the best double slit experiment explanations, like ever.
2. Easily deals with the myth of the conscious observer.
3. Answers the main question very well.
I do not agree with point 3
Aufenthalt perhaps so. That is why I have asked my question and hopefully clarified the issue to be “information”
Watch some videos of Don Hoffman. And then review those 3 points.
Christoph Küstler I have and shared them with my colleagues and will discuss in upcoming meeting next week. Thanks
The problem is the definitions of information and observation are ill defined. Invoking some kind of quantum akashic record doesn't get rid of consciousness.
The use of the words “observation” and “measurement” in quantum mechanics is thoroughly misleading. Replace them by “interaction” and things become much clearer. A probability wave exists only while it’s _not interacting._ When an interaction takes place it collapses. An interaction is an _exchange of information._
Nice video - intuitively appealing and convincing.
Good suggestion!
If it acts like a wave it’s a wave...same as photons. The waves collapse directly because of the detectors. Therefore you get a single position just like any other particle or macro object. What the field is and how it interacts with spacetime (unknown fabric they speak of) is yet to be discovered. Perhaps the microscopic particles, which are pure energy, cause ripples in the fabric?
Right, but thats not the whole picture. To be more precisely you should also say "when an interaction took place, takes place or WILL take place", and this is where it gets so mind-boggling.
How soon after it interacts can it go back into a probability wave? How is this defined?
@@muftiadnan the collapse of the wave function is thought to be irreversible.
This really sounds like a way a developer would optimize his code in a universe simulation (if no record is being made, then use the standard wave behavior) that is crazy to think about
huh that is interesting
I was thinking the exact same thing! I'm surprised someone else thought the same thing.
The weird thing is that there are many observations about our universe which could possibly be explained by thinking of the universe as the equivalent of a computer simulation. But the double slit experiment is an example where the simulation analogy is the ONLY way it makes any sense (at least in my mind).
Yes. Simulation theory. Go ahead and read about it.
Rafael Maia bruh don't talk like the other person is dumb, i have read a fuck ton about way before i watched this video, curb this rudeness dude
Zack Szekely yeah I've noticed that, it's overwhelming the ideia that maybe we're simply in a simulation, that would be cool nonetheless
I’ve never found such a succinct and graspable explanation. So well communicated, thanks!
Exactly, his explanation on observation and measurement in a previous video was great and easy to understand for people like me, who really have little to no clue what any of this means lol
This explanation is stupid...
My closest guess of why this is, is that every probability wave plays out on a field. You can't measure something on that field, without putting something else into that field to measure. The moment you do so, you change the shape of the field. Which changes the probabilistic outcome of deterministic processes that occur within that field.
it is sufficient to turn off the device...
Amazing. I love how you approached this. I gained a unique perspective on quantum behaviour that i didnt get from any other attempt at this topic. Nice one!
I just can't believe I've found the best video ever explaining this matter. Thank you.
All known matter(;?
This really is an amazing video
You didn't. Too little math and too many false or hand-waving statements. This isn't good
@@DAG_42 False statements? Like what? And why do you know better? We'd like to hear an actual explanation. And it's not because I want to challenge you, but because I want to know how it actually works if it doesn't work like this. If you know better, share it please.
The best
This is priceless content. Maybe this speaks to my stupidity but this is the only channel where I don't have to sort out confusion born out of the content I'm watching. Your videos make me feel like I moved slightly forward and leave me asking new questions. Thanks always!
Spoiler: he doesn't shoot ultra fast tennis balls
So you're saying it wasn't properly tested
Damn, he can't beat Matt yet
Why does everything have to be made into a joke nowadays
@@danielissah9741 these kids and their debroglie memes
Would be interesting if someone brings John Isner just for this purpose
This may be the best explanation of quantum mechanics I’ve heard yet....thank you
Goran Vukovic explain then
Goran Vukovic thinks that’s what he ,ore or less said in the vid.....but ok
Ive watched 6 or 7 videos explaining the double slit experiment. I happened to click on this one just for kicks to see if I missed anything. Im glad I did, the clarity of your explanation about information made many things click for me.
Didn't he forget to talk about the double slit experiment midway through the video?
And that clicked for you? XD
This might just be me, but I've NEVER heard someone give such a solid, succinct, and easy to grasp explanation for the whole "what could potentially be a measurement in quantum physics" thing. I've always kind of struggled to understand it before, but your explanation, combined with the examples about how hard it would be to -not- measure something like a tennis ball, made it all click for me. Thank you!
Glad it was helpful!
There’s not one video that explains the double slit experiment so well as yours does. thank you
You need to watch the holographic workshop all 10 parts mate.
actually there is. ua-cam.com/video/Q1YqgPAtzho/v-deo.html
In order to "measure" the photons passing through the double slit experiment, wouldn't that entail some sort of physical external interaction with the photon? It makes much more sense that this action would materialize the wave function into a concrete phenomena as you've effective imparted external influence on it. I think a lot of people are thrown off by the use of the term "measurement"
yes, a physical interaction is perhaps a better way to describe it.
@@ArvinAsh If that is indeed true, then calling it a measurement is simply misleading.
I've seen a double slit experiment with a polarizer as the "measurement" object. But a polarizer forces the particle into a specific state, but doesn't tell you it's state before it went through. Ofc that can erase the interference pattern!!!!!!!!!!!!!
I think, I finally found the puzzle piece that was missing in this double slit experiment. It's that the media omits crucial information to make physics sound like something mystical.
Aaah, this is SO disappointing...
This is the clearest explanation I've ever seen. Thank you.
This is exactly the problem I have always had with the terms "observation" and "measurement". Both terms imply a passive approach. There is no such thing as "passive" measurement in QM. And since by measuring, you actively interact with the photons, you collapse their probability wave into quantum states. Where is the mystery? At this point, I suspect physicists conciously don't clear this up to keep up the state of mysticism :)
NOW I understand why making a quantum computer is so hard - the superposition collapses from an event as trivial as the emittance of some blackbody radiation (which explains the extreme cooling).
The blackbody radiation isn't a problem as long as you make sure it isn't measured in a way that allows you to reconstruct the path even in principle - see the concept of a quantum eraser.
Exactly. Talk about extremely sensitive computing.
Even after all these years, quantum physics never fails to be weird
human's being here is just werid
*+Ken Smith*
I just love that.
@@Nova-fx6kr that is basically the most accurate depiction of humanity
Oh my goodness this is the best and the first time this has been explained on UA-cam . Great job!
That chart of wave interference merged with the bell curve is brilliant and illustrates a point perfectly.
I agree. A lot of viewers, I think, don't keep watching up to that part of the video.
The best discussion of the double-slit experiment I've ever seen! I'd love to see you go into more detail as to why small-scale objects are more informationally isolated than macro objects. It's one of those "seems obvious' things, but it seems to be at the heart of the measurement problem. Could atoms have their wave function "chipped away" instead of collapsed in one fell swoop like photons? How long can "large" things like molecules stay isolated, and under what circumstances?
If you make the measurement intentionally faulty, so that it fails say 25% of the time, then the collapse of the interference pattern may not be total. Look up quantum decoherence.
In an experiment done in 2019, molecules with masses greater than 25,000 atomic mass units, remained in a superposition for more than 7 ms
The wavelength though becomes smaller as the mass grows. So the interferometer you'll need becomes bigger.
To detect the wavelength of one thousand times smaller than a hydrogen atom they've built an interferometer with a baseline of 2 meters long.
As I understand it, that would mean that it's possible that if isolated, macro objects behave very much like waves. It's just that you wouldn't notice it since the wavelength is infinitely small
correct, weak measurements of the position can be made to keep most of the interference while gaining information on where the particle or photon is generally at or it's speed and direction, this was done in the area between the double slit and detector, and was used to create a map of the paths photons tend to take between the double slit and the detector. the result was similar to the path models that de broglie-bohm/pilot wave model predicts.
Quantum superposition would definitely make sports more interesting if it did occur on large objects. Great video!
Question: your argument about "theoretical" possibility of always determining the path of tennis ball, works the same for particles, no? Particles have gravity, photons interact with them, and so on. So it is also impossible to isolate them in theory. What am I not understanding? Thank you.
Danuta Galecka I have the same question. I feel like looking at it with the Copenhagen interpretation is incomplete as he said that the wave interference still comes up with molecules for 2000+ atoms. Surely these interact with photons around them, have a gravitational pull and also (I would think) have some kind of blackbody radiation.
The thing is that particles are always where the probability wave is high, the higher the wave the higher the probability that the certain particle will be there once you measure it, there is a principle called the uncertainty principle, the uncertainty principle says that you can't know the exact position and momentum at the same time, you either can know it's position but not momentum or vice versa. The quantum world is very very different from our classical view of physics. You can't know the path of a particle cause it doesn't have a path, it's anywhere where the probability wave is high
By looking at heisenberg’s uncertainty principle, it can be seen that the more is known about the momentum of a particle, the less is known about its location, and visa versa. Basically, imagine that you draw a line on a piece of paper that represents the path of a particle over time, you know it’s direction, but you don’t know where the particle is on that line. Now, if you drew a dot representing the particle at a certain time, you know it’s location, but have no information about its momentum. It’s an interesting theory and can bring to light the reasoning of a lot of other parts of quantum mechanics.
Danuta Galecka particles can act with the properties of waves, calculated by using de Broglie wavelength calculation, meaning at that it would not be affected by fields such as gravity, etc. However, tennis balls are so large that for it to have the properties of a wave it would have to move so incredibly slowly it would be staying perfectly still. Otherwise, it’s wavelength moving at 50 m/s, or a tennis serve speed, would be smaller than a Planck length, so meaningless.
I agree that this is still an issue. Under this definition of informationally isolated, I wouldn't expect electrons to exhibit wave behavior in a double slit experiment. I don't see how the uncertainty principle addresses this at all. Regardless of the de Broglie wavelength, there would be gravitational information encoded in the path. I also suspect this is an issue with the Copenhagen interpretation and the (in my opinion dubious) link between information isolation and wave function "collapse"
Was dying to know the answer about the behavior of macro objects ever since I learned about the dual nature of quantum particles. Thank you arvin 🙏 love your videos. You and PBS Spacetime are the best UA-cam channels 👍
The true mark of a master is one who can explain to non domain experts complex or abstract ideas without using the terms and nomenclature of the experts’ domain
Absolutely love your quantum videos, especially in the way that you are able to explain difficult-to-grasp concepts so eloquently and clearly while also touching on the beauty and mystery of the quantum world
Glad you like them!
I loved your explanation. You launched my mind into directions it had never imagined before.
This is the only video that makes me understand "measurement" / "observation" deeper and further.
Thank you Mr. Arvin Ash.
This was a really clever and original topic for a video. I watch a lot of science video's this is the first time I've seen this topic. I have always wondered the answer to this question but honestly I didn't think there was an answer or that anyone would really understand the question. Now I know! This channel is the best.
Finally someone said in simple words what I have been thinking for 10 years of what "observation" means. All physicist use this term in popular science entertainment all the time, but nobody ever bothers explaining it.
And I've never before heard about the wavelengths of macro objects in superposition approaching a point. This is such a simple explanation, but somehow nobody felt the need to ever mention that.
It doesn't make a difference seeing that a record is only a record if it is (in principal) interpretable.
Records are just detours along the way to concious observation.
I am still confused, how do they remove the observation effect in the quantum experiments?
You are out of this existence with these amazingggggggg explanations. Forever previledged to have found your channel!
While watching this video, I started getting frustrated thinking about the definition of observer, a thing in many quantum mechanics explanations that gets skipped over. But then you go and provide the easiest to understand definition I've seen yet! It was really useful to be able to actually understand the importance and implications of information isolation.
Its like being trapped in a Truman show with everything surrounding us in synchronized conspiracy to keep us from finding out that we are the ones being watched.
Don’t let mark Sargent see this
It would certainly be a handy bit of code if you're running a complex simulation and want to ensure that nothing interferes with the progress. Like a firewall built into the basic code of the program to prevent external information from corrupting the data you're trying to collect.
I'm pretty sure we're on TV As Above So Below.
You know those characters on the TV show that their self aware that there in a computer and they want to get out.
I'm pretty sure we're all agent Smith.
But I'm also pretty sure we're all Neo.
But I'm also pretty sure there's a Main.
And a judgment.
But I feel like someone needs to be sacrificed.
I legit saw that s*** and then I'm the one that gets called schizophrenic.
I ain't man enough.
Thank you! Finally, someone gets the dead/alive cat scenario right. I get so tired of people saying that 'the cat in the box is alive and dead', because they don't understand what a paradox is. It's very refreshing to have this explained properly.
the cat is dead, because to isolate it, you need to put it in a vacuum (among other considerations), which would kill the cat
Schroedinger's cat is not even a paradox. It's just plain nonsense that doesn't want to die. Kind of like religion.
So if a tree falls down in a forest and no one’s around it DOES make a sound. Got it.
It makes a pressure wave. Your ears and brain interpret it as a sound.
Well this is because we know from the past experience that it'd make a sound, i.e. the belief that the future will act like the past.
@@stivendog Not quite, "sound" is what we call a pressure wave in a medium. Ear receives and brain interprets but the sound (aka the pressure wave) still exist without ear and brain.
Yes, like Schroendinger's cat it's either dead or alive, but not both at the same time.
Yes! ua-cam.com/video/QN_-fyBegtM/v-deo.html
Damn, getting the answer only gives you even more questions :(
This is the best video explaining waves and particles. You nailed it. I finally understand the double slit experiment.
From time to time I run in to these videos about double slid. Thing blows my mind every time.
It wouldn't blow your mind if you knew that photons do not exist and all the slit experiments prove the light is only ever waves.
@@dreamdiction why does it change then when you add an observer?
@@yoooyoyooo There are no 'photons', light is waves at all frequencies, there are no particles. It is a thought-experiment, the "photon detector" is an imaginary mathematical probability idea, not a real device. It is impossible to passively tag a wave (or a particle if you prefer) with an identity as it passes through the slit, the only way to detect a wave is to put physical matter in the path which consumes the wave energy by absorption so obviously nothing would come out of that slit. It's the same wave which goes through both slits and causes interference from two separate slit sources on the other side. The interference experiments do not have any detector because that would block the wave and cancel the interference, that's why NONE of the interference demonstrations have detectors, that's why you are only ever shown graphic cartoons of detectors collapsing the wave functions from slits.
@@dreamdiction why is everyone making such a big deal out of this if it's that simple?
@@yoooyoyooo There is no wave/particle duality. Physicists had developed a system for analyzing waves, so they applied their wave-system to matter by treating matter as waves, then followed the converse proposition by treating waves as matter. The wave/particle duality is merely the nonsense of misapplied system analysis.
Electromagnetic radiation (EMR) is waves at all frequencies, never particles. Every experiment shows light is waves, there are no EMR particles, there is no duality. What they call "single photons" is a high frequency interrupter relay transmitter switch used to produce single separate individual wavelengths, like this ~ ~ ~ ~ ~ not "photon particles".
Continuous waves produce interference patterns and intermittent separate single waves also produce interference but at a slower rate/intensity because of the gaps between waves. The interference is the proof that light is waves at all frequencies, never particles. "Probability waves" only exist in researchers imagination, that's why nobody (including de Broglie) could design an experiment which shows light is particles.
The photoelectric effect is easily explained by blue light having the right frequency of positive/negative magnetic induction (alternating push/pull) to magnetically agitate a negatively charged election out of it's shell orbit, that's why the photoelectric effect does not work at higher or lower frequencies - nothing to do with "particles". Did you believe red light was waves but blue light magically manifested 'particles' which disappeared again at higher frequencies.
Electromagnetic Radiation (EMR) is waves at all frequencies, all the experiments show light is waves, there is no experiment which shows light is 'particles'.
The "photon detector" is an imaginary mathematical idea, not a real device. It is impossible to passively tag a wave (or a particle if you prefer) with an identity as it passes through the slit, the only way to detect a wave is to put physical matter in the path which consumes the wave energy by absorption so obviously nothing would come out of that slit. It's the same wave which goes through both slits and causes interference from two separate slit sources on the other side. The interference experiments do not have any detector because that would block the wave and cancel the interference, that's why NONE of the interference demonstrations have detectors.
There are hundreds of videos showing the actual double slit interference but none showing the actual wave function collapse as the interference pattern disappears into observed "particles" because it's only a thought-experiment.
Quantum electrodynamics textbooks give a summary of the discussions between Bohr and Einstein in which they each propose a variety of impossible imaginary "detectors". They were just talking, the 'detector' was just an idea.
Physics had a well-developed analysis of waves, so as a thought experiment they started treating matter as waves, later they reversed the thought experiment and started treating waves as matter, the self-induced paradox of the two thought experiments created wave particle duality and 'spin' only exists in the minds of believers, not in reality. Schrodinger published his cat in a box thought experiment only to demonstrate the absurdity of the wave/particle duality idea, Schrodinger was later very surprised to see his absurd cat in a box story being used to demonstrate the true nature of state vector collapse wave/particle duality.
Relativity and Quantum Electrodynamics are thought experiments, that's why cosmology and QM are a cult-like belief system with a priesthood guarding their made-up doctrine by excommunicating doubters, for example, it is impossible to have academic career in physics if you say there is no proof that black holes exist. There are some places in the universe which seem to have more gravity than expected and some of these places seem to have more gamma radiation than expected, that's all we know about "blackholes", everything else is speculation, but if you publicly say this you become an outcast without any academic employment prospects.
Go and search for actual experimental evidence of wave/particle duality and you won't find it, because it does not exist. Electromagnetic Radiation (EMR) is waves at all frequencies, never particles. You must have suspected this surely?
One question: Photons are affected by gravity and therefore give information about their position. This means i can essentially revert your question: why doesn't a tennis ball act like a photon to: why don't photons behave like a tennis ball if they give information?
Exactly what I was thinking! Bravo! Similarly, the light emitted from the monochromatic light source is an electromagnetic wave so it interacts with magnetic and electrical fields, so in the laboratory it must exchange information with the universe via the fields present there. So why is that light not exchange information with the universe.
@@XEinstein
My guess is, that this interaction is too week as that the "information gain" it contributes gets wiped away by the Heisenberg Uncertenty Principle.
Edit: Also after rethinking.
The slits in the double slit experiment have a finite but non-zero width. Some photons/electrons may get "smahed" against the border of the slit and thus have to present through which slit they go (same for photons/electrons which interact with eg an oxygen molecule from air before the slit), but for the majority the deviation is much to low. They still are not forced to go through one slit and present which slit that would be. There is plenty of space in the slit to allow for small devitions left and right.
So in a nutshell: the width of the slit insures that small deviations do not force the particle to present the path information.
BEST explanation, most basic I have ever heard and easy to understand. Based in theory and testing using the scientific method. Wonderful job.
I have a few thoughts about this video:
- it's fantastic - thank you for putting it on!
- If small objects are "informationally isolated", that prevents time travel. Theoretically, if we knew the position and velocity of every particle in the universe we could determine where every atom was a millisecond ago, a second ago, a day ago, and as far back as we want. And the same thing would happen to time travel travel to the future. If we had complete information about every particle in the universe we could determine where that particle would be a millisecond from now, etc. How disappointing. As if Heisenberg's "uncertainty" was not enough, the universe puts a second lock on the door to time travel.
- I have a different idea than the one given here about why firing photons one at a time still gives a wave pattern. The wave does NOT collapse. (what a silly idea).
The universe is not a giant empty room just waiting for photons to come flying through. According to another video in the series (I already learned from this video series! Thanks!) the universe is a container with 17 fields running through every part of it. (ok, it's not really a container lol).. Therefore, we are not firing a photon particle in an empty shooting gallery. We are sending a PROTON WAVE through a room filled with fields. Whether we fire one or many photons makes no difference. What I think is happening is that the PROTON FIELD "bumps into" the other fields that make up the universe. THAT is what causes the interference pattern. The photon is not interfering with itself (another silly idea). It is simply interacting with the background fields which are the fabric of our universe.
- The only reason I was able to make a statement about the universe and Fields is because this lecture series is so wonderful.
Well, professor, how did I do? I am a retired NASA engineer, and I did not get deep into physics in my work or schooling. I find these lectures fascinating, even if their content is elementary to every child on K-Pax lol. (reference to a movie with that title).
Professor @Arvin Ash 10/10
What I think is happening is that the photon is never a wave. It is a particle that only is located somewhere when it interacts. The wave part is the probability of where it will be if it interacts. The probability wave interacts with itself, causing the interference pattern
@@vibaj16 I dont think that explains why they’re different when observed versus not though
@@Limbaugh_ It does though. Note that I said "It is a particle that only is located somewhere when it interacts", as in it chooses where it is at random the moment it has to interact
Great explanation about where and why the “cutoff” is. It’s a question that’s been lurking around my mind for a while - at what point does quantum behaviour cease. Thanks.
Quantum mechanics is probabilistic, so you can calculate the number of atoms required for a probability measurement greater than something like .99999999 (imagine even a .0000001% chance of quantum behavior for a tennis ball.... I think it's much lower for our macroscopic objects). I'm not sure the exact cutoff, but it's possible to calculate. The reason quantum behavior disappears with macroscopic objects is due to the degrees of freedom decreasing with increasing number of particles. Maybe think of sand verse a large rock - the rock is rigid, and the internal behavior is very constrained. Sand, however, is able to shift and flow around. It has much more degrees of freedom than an atom inside the rock. When we think of quantum particles, they lose degrees of freedom as they form together. The less degrees of freedom, the more information that can be determined by measurement. The number of particles required to return a probability of a measurement greater than .999999999...... is when quantum behaviour stops.
nick I never understood how ppl on yt can create comments like these, obviously well known on the topic of quantum mechanics, but can’t help to wonder if the person typing is a professional in the field, or an average joe like me who’s a lot smarter than I am.
@@saltycatagenda I like the sand/rock analogy. Another one I like is the number of times to flip a quarter and record its number of heads and tails. We know it has a theoretical 50% probability of getting heads. And the more we flip, the closer we'll get our experimental value to be exactly 50%. So if we flip a quarter 1 trillion times, it's like an object gaining 1 trillion particles, it becomes certain to be 50% with high certainty, in other words, the object loses its wave function or probabilistic property to become a discrete unit of the macro world. The cut off is the entrance/exit between microverse and macroverse.
@@itanimulll that's the beauty of youtube anonymity and the horror of it!
Bryan so in the end there isn't even a real exact cut-off so much as the end result being so extremely consistent to a certain degree that the stranger possibilities have negligible impact. And the opposite being in the result being far too uncertain that you're stuck looking at a wave function with missing details no matter how hard you try.
I'm a not scientist nor a physicist, I have a basic school physics education from 55 years ago, which never covered atomic physics as it was called then. However, over the years, I have always been intrigued by the weirdness of the double slit results and the conclusion that followed from them, which formed the foundational explanation of the behaviour of light and quantum particles as understood now as quantum mechanics.
I have watched many videos on just this topic and formulated my own hypotheses which can explain all the results, including; the measurement observer problem, particle/wave duality, all without any weirdness, like waves and particles transmuting in to each other depending on if they are being observed or not.
I found your video very interesting and used your video expanation to test my hypotheses and I can explain all your results perfectly simply, using my hypotheses without any weirdness.
Because you are a physicist, I would love to discuss this hypotheses with you and for you to try your best to break it. I don't think my hypotheses changes the maths around QM, however it could give physicist a new way to look at things and like all good hypotheses, it makes predictions about things we do not yet know, which people like yourself can do the experiments to confirm if the hypotheses to be true or not.
Sorry for rambling on so long, thank you for your videos, very enjoyable!
This is the most visually digestible explanation of quantum effect I have yet seen. It greatly helped me to understand a little bit better the dichotomy between macro physics and micro physics. In some ways it reminds me of the philosopher George Berkeley's question, if a tree falls in the forest and nobody hears it, does it still make a sound? I presume we can never take a measurement without interfering with a particle. We believe this interference (interaction?) changes the observable behavior of the particle. If we could take a measurement without interfering with a particle, would its behavior still change, or would it not change? Does the act of measurement, even passive measurement (if such a thing were possible), create a false perception of the event, or does it create a new event (in which case it isn't false)? In the macro-universe we see no observable discrepancies because the joining together of enough particles permanently alters the behavior of these particles. I find this idea comparable to the Gestalt psychologists' famous dictum that the whole is greater than the mere sum of its parts. The joining of enough particles changes the dynamics of those particles in a way not possible when the particles remain far enough apart (what constitutes far enough?). In effect, we are talking about two different universes, one completely joined, and the other completely disjoined (one might say unhinged). Can this latter universe even exist outside of the laboratory?
"If we could take a measurement without interfering with a particle, would its behavior still change, or would it not change?" we can get close, weak measurements have been made before, slightly disturbing the interference pattern, while giving slight information
Wow, I understood ~90% of all you said.That's awesome with regard to the complex content. Great channel.
9:27 That’s the explanation I need! Thank you
Thats enough👍
just a sidenote, while it is true the copenhagen interpretation is the most accepted, it is not accepted by a majority of scientists.
I find it fascinating we have all theese well tested results and can't make heads or tails of what they actually mean
advances.sciencemag.org/content/5/9/eaaw9832
To say that Copenhagen is accepted is to say that scientists have accepted that they do not understand quantum physics... It should not suffice.
Do people believe in a deterministic theory? like the EPR Paradox?
Is this a confuse way of saying that less than 50% of physicists accept this interpretation as a true description of quantum mechanics?
@@Amani_Rose Due to the Bell's theorem, either hidden variables are correct or quantum theory is correct, but not both at the same time. Experiments with separated entangled particles have been made, dismissing determinism.
Wow. I've been watching loads of physics vids recently. PBS space time, Fermi lab, Up and Atom...
This is the first time I've fully understood something! Mind you, I am a little bit stoned, so perhaps that helped.
Arvin Ash, thank you. This is easily one of the best and most technically correct explanations I’ve seen of why it is so hard to keep large objects quantum. Far too many “easy” explanations focus solely on the wavelength issue and neglect the critical impact of just one atom or photon. Well done!
I must also apologize. I’ve ignored your channel for years due to an incorrect impression - I don’t recall from where - that yours was one of the everything-is-mystical channels. That was wrong, and I am sorry I did not check back sooner.
just wanted you to know when u say "coming up, right now" gets me more excited although i don't understand anything you say 😅
SAME
Are you dumb or like 15? Because not understand a single thing is really worrying.
This is hands down the best explanation about the DS-experiment that I have seen. I especially like this "informationally isolated"-concept which allows me to understand the phenomenon just a little bit more which has not happened for a long time despite watching a lot of DSE-videos. It's almost an insult that you don't have millions of subs already.
Arvin Ash explains quantum physics is a way that it is easy to understand, and, at times, asks questions that I have not encountered in other videos.
Hey wow, really good! I’m impressed. Nicely done message, easy to absorb by an amateur.
How is it possible that larger molecules don't let any print ? No gravitational or nothing ?
He didn’t say that. Maybe the answer is that an individual large molecule’s forces enough to keep other individuals far away because of distances between them so big when comparison to their size unlike big object’s.
I think it implies that a large proportion (probably not all tho) of those large molecules in the experiment do indeed 'sneak' through without any interactions, avoiding pretty much all other particles in their way and not absorbing any meaningful quantities of photons. Since some proportion of them does interact, you could probably see and measure some deviation in the results when compared to smaller particles, maybe a more muddied interference pattern. Also, maybe they did freeze and vacuum everything, whereas for tennis balls you'd need some seriously larger effort to do so. All this is just a guess on my part tho
yeah, because gravity goes on infinitely, even one atom has gravity, even if it's extremely small, so it is interacting with everything around it. What's the cut off where it matters? Is it the point where it makes another object move a plank length?
Why was this not at the top of the search results for double-slit. YT and google need to employ people to work this out for such important topics. They can surely afford it and it would advance science. The algorithm alone does not work! Finally, I came to a very good video. Thanks!
I'm a complete physics layman. But *three years ago,* in a science discussion post on reddít, I first noticed and pointed out the convergence of wave-like behavior of atoms into classic macro particle behavior when the relative wavelength becomes super-tiny. I was *laughed at* for suggesting something that silly... so now I feel vindicated -- thank you!
I finally realized that any measurement is the interaction of the device and the measured object. And the interaction isn't something ephemeral, it's a particle/wave. So we measure the data of the particle/wave that carries information about our studied object. Moreover, the presence of a measuring device is not necessary, it is enough that there is an object in the universe basing on which parameters we can calculate some data of our studying object.
It's a wavicle.
😂👍
No, the presence of a measuring device is exactly why the "collapse" occurs.
You cannot "measure" something without affecting it and at the atomic scale any kind of such measurement is going to affect the particle.
In short it isn't about the "information" or "superpositions" or whatver, but the experiment itself being impossible to conduct at the fundamental level.
It's like saying that a ball isn't flying in a straight line, because you hit it with another ball to "measure" how fast it's going. Of course it ain't going to land in the same spot as if it wasn't hit, so what exactly is this experiment proving? Certainly nothing about quantum physics.
This is the best explanation ever!! Love your videos.Excellent work!!
Another great explanation. I'm just wondering why gravity from other atoms doesn't have an effect on a 2000 atom molecule?
It will to some degree. This is why these experiments are difficult to carry out - it is difficult to isolate larger atomic structures. I am not sure of the experimental setup, but it would need to be isolated. If there are enough molecules fired to the slit, then there may be enough molecules to get the appropriate patterns even if a portion of the molecules get "measured" on the way to the slit. This will just result is some fuzziness of the patterns which are part of the error.
@@ArvinAsh
Exactly how do scientists isolate every other particle in the universe from another's gravity? That seems impossible.
Anonym Ous Exactly. I don’t understand this either, it doesn’t seem possible.
@@AnonymOus-ss9jj it's not about isolating particles from gravity. He never said that. The concern about gravity was that it can attract smaller particles to the one being put through the experiment. The truth is we've never created a true void. With smaller particles they can slip through spaces between the few particles in a void more easily without gravity pulling them to it. With a tennis ball, our current voids cannot realistically prevent a chamber from having enough particles left that the tennis ball wouldn't hit at least one on its way. And if it would miraculously miss any tiny particles, it doesn't once you factor in gravity to attract those particles to the ball, making collision unavoidable.
Anonym Ous it’s because gravity is an exceptionally weak force. It creates negligible noise.
Hm, I knew the physical size of wave function's "total most probable" area of macro objects is extremely tiny, but I never thought about "information isolation" part. Of course, it's totally correct: any contact AKA "measurement" collapses the wave function. But to think of it, we can't make these "informationally isolated" because macro objects are defined by mutual interaction of their particles: they are more bound together than they are bound with outside world (otherise it's not a single macro object but a collection of objects). And any interaction will collapse the wavefunction of particles or atoms interacted upon (thus, any chemical bond or gravitational interaction will fix the positions of several atoms). The only place where non-fixed particles can be found is deep inside atoms where they are not directly acted upon.
@4:53 - what about the same wave-like behavior found with 2000+ atoms?
this channel is a gem in whole youtube. these videos should remain forever to help generations understand
5:36 Hold on, isn't the whole point of the Delayed Choice Quantum Eraser experiment that when you scramble the information about which slit the photon travelled through the interference pattern still occurs?
Yes. I believe Arvin had not heard about this experiment.
@@KennyT187 He got a video on the subject from 2019.
@@flawmore Yeah I noticed actually.. so he was a bit off when he said the interference pattern is lost forever. As long as we do not entangle ourself with the which-path information the interfence can be recovered.
the universe has already recorded which path was taken before the hard drive was destroyed, in the quantum eraser experiment the path was never recorded 'by the universe'.
There I was thinking I finally got it until I saw your comments…
Very well presented, it is still a wonderous situation!
Yes it is a 'wonderous situation'. Well said.
I seen so many dbl slit experiment and read up on it and also watched allot of videos and read books on quantum mechanics and the behavior of subatomic particles and this is the best video to describe why macroscopic objects don't behave the way microscopic objects in the quantum level.. thank you so much for this video.. really enjoyed it and love your channel.. thank you again sir
Every time I think I'm smart, I watch videos like this, then I go and watch flat earther videos to feel smart again.
You are in a superposition state of intelligence until you watch a video. Then a measurement took place and the intelligence function collapse occurs.
Arvin is easily the best science explainer around these days, this is the first time I've been able to grasp this concept after trying to understand it for over a decade now. Please don't ever stop teaching, you are the best!
Whinge: Even though i'm subscribed, YT didn't recommend this video to me, I had to click on your channel to see if you had uploaded anything recently, meanwhile I get bombarded with videos from dumb reaction channels every day that I'm not even subscribed to!!
Thanks my friend. Yes, the UA-cam algorithm is a mystery to even the best scientists!
Your UA-cam experiences are being caused by the interference patterns of the waves - you're in a double slit experiment. 😆😆
It's interesting that the go-to example for this is tennis balls. In my Intro Physics textbook, the section on Quantum Mechanics does the same calculation of the De Broglie wavelength of a tennis ball and shows how its quantum behavior is entirely negligible, even if you were to work out a way to not have the wave function of the entire object collapse from interaction with its environment.
I've also seen the supposed diffraction pattern for molecules consisting of several dozen atoms, and it's barely discernible from a Gaussian. There's only a very slight dip in the probability off the center of the peak before it returns to the normally expected Gaussian.
Best explanation I have seen on this topic. I finally understand.
As always, excellent!
One way to interpret the Quantum Eraser Effect, is to imagine reality being recorded in 2 ways in the past, one way as particles, the other way as waves. When our "listening device" is set to measure particles, that is what we record in the future; and when our listening device is set to measure waves, that is what we also record in the future. The Quantum Eraser Experiment is a rather prosaic experiment: it is only showing that reality is recorded in 2 separate forms and that you can observe those recordings in 2 separate forms in the future. IT DOES NOT PROVE THAT WE INFLUENCE THE PAST WITH CURRENT OBSERVATION.
This youtuber deserve millions of subscribers🙌🙌🙌
He says: "of course not" with certainty while discussing quantum mechanics 🤣🤣🤣🤣
I've seen a couple videos on this topic, but it's the only video that helped me understand, why observing the particle changes its behaviour. Thank you very much
When nothing needs to know where it is. Its literally everywhere it can be.
its because when you make the measurement, you are forcing yourself into a very specific quantum btranch of reality. And until you are in that specific branch, all possibilities exist, as literally everything that possibly can happen is happening in the Universe.
@@Scorch428 that interpretation isn't proven
This was the best explanation I ever seen on the double slit. It’s weird to think how even our thoughts are connected to everything. Great vid Arvin, 👍
We love how it connected the physical to the metaphysical. A beautiful storytelling. 🌸❤️
You deserve more than a million subscriber ❤️♥️
2 comments, guess u want arvin to like your comment
@@harshitsrivastava7700 i hope so 😊
harshit srivastava haha you keeping track
I always enjoy watching your content. Everything is so well put together. Keep up the good work and spread the science! 🤜🤛
This is aboslutely FABULOUS explanation!
I think I'm fundamentally missing something with the whole double-slit experiment. Isn't it just that the act of measurement breaks the symmetry of the previously cancelling wave-forms, resulting in the collapse? What confuses me is why would this be unexpected? What you're left with is the difference, like with/without noise cancellation? As for restoring it, or eraser experiments, isn't that just moving the shapes back into alignment for them to once again reconcile/cancel?
Side note, I would guess it breaks down about halfway between measurement apparatus and the target, as what you're actually disrupting is the chain of probabilities between? But truly I can't imagine a way to know, not until someone figures out a way to assess probability without interacting with it. It would take a perfect reproduction of the conditions to test independently, I think, and there is literally no such thing possible, because "conditions" are not the lab, they're the universe. GG, physics, you win this round.
Also, I wonder if it isn't short-sighted of us to assume we're seeing everything happening that can be seen. What we perceive as nothingness (and not just in this context of this particular experiment) could just be forms of matter and antimatter cancelling out within the window of a single unit of Planck time. At that point all we can do is catch a glimpse of it. We can't see it starting and ending.
I figure, the best we can hope for is that it'll overlap on a frame boundary and we can see part of its life in that ultra-brief glimpse we're afforded, and maybe, we could stitch together enough of those overlaps to see a more complete picture? Isn't that basically what they're doing with the LHC? Trying to creature enough of these sub-Planck-duration particles so as to catch one or two of them at the boundary?
Lastly, I'm happy to be wrong on absolutely all of this and be pointed towards additional awesome videos. Cheers.
THANK YOU!
This has also been confusing me for years, ever since I first became interested in physics. No matter where I research I can't even find a conversation about how the act of measurement could be interfering with the results. Glad I'm not the only one who is confused about that side of it lmao
This show is so cool.
Best video on quantum mechanics I've seen so far. Mostly because easy to understand for the layman but still be accurate factually.
Wla!! Finally I get the answer I was looking for.. Thank you!
I realize it's tied up with Copenhagen, but I think it's pretty clear that information coupling with the universe is not a binary thing. When we send electrons or molecules through they are definitely coupling with their surroundings through gravity and electromagnetism, but the coupling is too weak to destroy the interference pattern. In order to make a measurement we need stronger coupling. I think there is a range between the interference pattern being pure and destroyed. And actually it may be more accurate to say that macroscopic objects do have superstition and interference patterns, they are just impossible to measure, as you even say.
Smart.
I’ve always been curious why macroscopic objects didn’t exhibit this behavior! Thank you for explaining it very well!
Question about warp driving: If we set electrons of atoms to closer ring to a proton wouldn't we get negative energy?
If such an orbit was stable, it might require negative energy. To put it another way, because it doesn't have negative energy, that orbit is not stable.
Love the explanation... My question, now, has more to do with the line that separates "the quantum" and "the outside universe"
This is the best video I’ve seen on the double slit experiment, it now makes much more sense to me. Thank you!
Question: how can the 'recording device' measure photons passing through the slits if the photons are travelling away from it?
@Heads Mess Okay, but wouldn't the recording device have some radiation coming off it that could interfere with the results?
@@erurevir if you have the same recording device, but dont have it output its resuly (so its basically just there), interference happens as normal. It only happens when it is actually measured
@@ichmag11 This contradicts what the video said: information is considered to have been recorded even if some infinitesimal particles collided with it and no measurement device made any attempt to track the information about the collision. Because regardless, that particle now has the information, so it has been measured.
@@erurevir You got it right. I think this video is a bit confusing: any particle has a probability wave function that assigns the odd as to where the particle will end up on the screen. When the particle interacts with something, the wave function changes accordingly. When you put a detector as you guessed you make the particle interact with something and so the wave function gets messed up and the interference pattern disappears.
The degree at which the wave function changes depends on how strong the interaction is, so for electrons unless you bombard them with photons to get their position, they will more ore less retain the same wave function and generate the interference pattern. Baseballs interact a lot with everything, so it's impossible to make them interfere (not to mention that 2 baseballs are never identical, so they'll inherently have different wave functions, plus the de broglie wavelength as mentioned is tiny)
Detector observed the results that atoms put on the board. Can't really say in which slit the atom travelled through. Probabilities can only be guessed.
I don't think it's accurate to say that the wave only collapses when it is _measured_ but when it interacts with another object. Our presence or knowledge does not have any influence on quantum behaviour, it is the interaction with the particle which is inherent in an act of measurement.
It is a semantics problem, in a sense it is measured if it interacts with anything.
Observed isn't completely correct either. Interacting might indeed be the closest English word we have to describe that behaviour.
That's what he said in the video dumbass
@@skyegibbs4955 But that makes the whole quantum thing a hogwash.
Finally understood what observerb in double slit exp. Means
Please do a video on Schrodinger's Suicide Machine - that is, any scientist who truly believes that the cat is both dead and alive would get in the box with the cat, in the belief that he would emerge in the timeline with the alive cat.
Schrodinger should have suggested a bomb instead of poison. Then he coulda argued the cat cant be alive and dead at the same time, bcus the box cant explode and not explode at the same time. Either that cat is blown up, or he's not blown up and we can verify that by looking at the box from outside. There is no superposition. That is a ridiculous interpretation for them to think this could be a physical reality.
Excellent explanation!!! Finally understood properly after years of reading about this. One question though: How are photons (or molecules up to 800 atoms) isolated from the rest of the universe if light itself is affected by gravity? And those molecules must exert some gravitational effect, however tiny?
I have the same question. And additionally, wouldn't the atoms in a molecule interact with each other, collapsing their wave functions?
Now I’m just thinking out loud but, maybe they don’t have to be isolated from gravity since that doesn’t necessarily make or record any information. If gravity bends space, then you can imagine it like the particles traveling in a straight spacial line that would be observed by us as curved.
@@MasterKoala777 maybe they just act as one unit, and if the molecule can’t interact with itself, no information is being created
He said it was noted in 2019 for molecules - worth checking around for reports about that test
Wow... I mean... Really... Wooooow.
Does this guy realize how seldom is anyone explained what observation even is? This is one of the most useful movies I have ever seen!
after 20 years alive, I can now fully grasped the idea of Schrödinger Cat. Thanks
QM is like looking under the code of the universes algorithm
This answered so many outstanding questions I had, Appreciate the effort of passing on the knowledge
Has anybody actually done the experiment with tennis balls?
I've been pondering this since I learnt of the double slit experiment (it was 1998!)
I've been designing the tennis ball version in my mind for 20 years.
It would be pretty easy to set up. I hope someone does it, and reports it here.
@@ArvinAsh Pretty easy are you joking? You need a coherent flux of tennis balls , meaning all the atoms of the ball have to get in coherent superposition (technically the statistical density matrix should be almost diagonal) and is not only matter of cooling.
Experiments have been done with Fullerene atoms (60atoms balls) and probably with virus sized particles. In addition Bose Einstein condensates of 20000 atoms show quantum interference.
I think the universe is on to us.
This is the best explanation I’ve seen so far.
*Why am I watching this. I know nothing about quantum mechanics. I’m not even in college.*