Anti-Matter and Quantum Relativity
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- Опубліковано 15 тра 2024
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Paul Dirac’s insights into the nature of Quantum Mechanics laid the foundation for Quantum Field Theory and predicted the existence of anti-matter. Part 1 in our series on Quantum Field Theory. Try Skillshare at skl.sh/spacetime
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Book recommendations:
The Quantum Divide, by Christopher Gerry & Kimberley Bruno
The Character of Physical Law, by Richard Feynman
Previous Episode:
Supervoids vs Colliding Universes
• Supervoids vs Collidin...
It’s 1928. Over the past quarter century, the greatest geniuses of the modern era discovered the two keys to the fundamental nature of reality. Einstein’s theories of special and general relativity had changed forever the way we think of motion, space, and time. And the emerging field of quantum mechanics had radically altered our understanding of the fundamental building blocks of the universe. Yet this year one brilliant insight would bring these theories together and unveil the quantum fabric of reality. It would also predict the existence of antimatter.
Written and Hosted by Matt O’Dowd
Produced by Rusty Ward
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Made by Kornhaber Brown (www.kornhaberbrown.com)
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Before channels like PBS Space Time, I was getting pretty tired of popular-science videos that only ever repeated the same tired analogies, pausing explanatory narration in order to stretch out the analogy with low-budget CG animations.
PBS is supported by viewers like you
atimholt That’s so true 💪
I only wish PBS would create a curse. Beginners topics up to most advanced ones. Or basics to most current topics
@@stefanluginger3682 ¹1
Word for word what I think, and thought at the time OP posted this comment.
(5:38) "But the resulting equation was so simple and elegant..." - *shows ancient alien runes*
Funny thing is is that is a simplified version of a simplified version of the equation
@A Frustrated Gamer :), as long as the math allows something, it exists
It’s greek
And Planck constant
@@chonkeboi can you explain the Greek subscripts and superscripts then Mr. Smart man?
"it opened more questions then it answered". I feel like this is pretty much quantum mechanics in a nutshell.
@A Frustrated Gamer , I've been led to understand that you shouldn't think of entanglement as transmitting information. As an example: Alice takes a white and a black marble, and puts them both in separate bags. She then randomly gives one of the bags to Bob. Once Bob opens the bag, he'll know the color of the marble in the other bag, but no information was really transmitted despite the two bags' contents being "entangled"
The only thing physics has done is open more questions than it has answered
@A Frustrated Gamer That sounds like causality violation though? Any chance you'd remember what that study was, sounds really interesting
@@user-en5vj6vr2u False. We just need to unify quantum mechanics and general relativity by changing something fundamental in either of them and it will be game over for everyone. But the problem is that physicists take fundamental things at face value and it's hard to say what we're assuming and what we're not assuming. We were assuming that time was absolute for all frames of reference until Einstein jumped into the picture. Who knows how exactly our intuition in misleading us right now.
@A Frustrated Gamer Einstein strongly believed that one should go after quantum mechanics only after relativity. One has to achieve things step by step. If you take a great leap , you might either reach the top or fall to the bottom and it seems like physics right now is falling because we're taking quantum mechanics as the base instead of taking relativity as the base. But we can just start from general relativity, then observe flaws in it and then jump into quantum mechanics and physics will be solved forever. Atleast I want to see it solved before I die or I'll dedicate my life to solve it.
I think it's worth pointing out that Schrödinger himself was no dummy, and wrote a fully relativistic equation before the one that bears his name. However, he didn't know what to do with the negative energy solutions, so he gave up (the Dirac sea picture wouldn't work for his equation because it described bosons and not fermions). This equation is now known as the "Klein-Gordon equation".
Good video as usual.
Indeed, the whole 'antiparticle of itself' thing always annoyed me and the history of those two equations is an interesting one.
I think it's also good to point out that this is not the correct, modern way to look at the Klein-Gordon equation or the Dirac equation, nor a good way to look at the relationship between the Schrodinger equation and relativity. This last issue depends on what exactly you mean by Schrodinger equation, but I'm writing a comment about this. The first one is an historical burden that arises from the confusion people had in the early years of QFT, but I'm always determined to clear this up.
I'm giving Matt a good benefit of the doubt here because he said he'll deal with QFT in a future episode. I don't know how deep he'll go, nor if he'll talk about creation and annihilation operators and the like, but I expect some of the Dirac sea confusion to be cleared up.
I know what you mean about the Schrödinger equation. The nonrelativistic limit of QFTs is indeed subtle.
It is indeed. Depending on what one means by Schrodinger equation, one can define the Schrodinger equation in a QFT without taking a non-relativistic limit (even though one gets a functional integro-differential mess), but the nonrelativistic limit is subtle. I always thought that it was worth it to be careful about these things. I trust Matt to be as well :D
What is prove that actually deep sea as proposed by dirac dont exist? and why there is assumption that antimatter is also annihilated with matter if we cannot percieve it??
Very excited for Quantum Field Theory.
I never want to stop learning.
Greg, feel the same as you, I want to use this stuff in my graduation somehow hahaha
Just finished QFT at uni. Very concept light and maths heavy :(
There's a UA-cam channel called "Thunderbolts Project", it's a channel that uploads videos about the Electric Universe theory as well as electromagnetism and the channel's fans and the comment section on virtually all of the videos they upload are usually full of people dogging on Relativity, gravity and even the theory of evolution (lol), does anybody know about this by any chance?
"Very concept light and maths heavy :("
A good QFT course is both concept and math heavy... ;)
QFT is by far the hardest subject I ever learned.
*leaning
To everyone who question this arbitrary addition of states to problems, this method isn't at all weird, convenient, or arbitrary. It's a conceptual hypothesis. The thought goes like this:
"What if there was 1 more degree of freedom that we haven't found yet? Well, let's see what the necessary consequences of such an extra DoF by working out the math. Oh look the consequences in the math world matches the observed universe very well. Until someone can explain this 'better' or find an experimental result that conflicts the necessary consequences worked out in math, the extra DoF will be taken as truth."
There's nothing weird or mystical about this process. Newton went through the same process. He invented this "force" that pulls "mass"es towards each other. It's a conceptual invention that doesn't require any other reason to exist other than the fact that if it were to exist, we'd be observing exactly what we're observing.
@@bmortomorton Why are you treating him as if he had a mental problem, it is just people making and testing hypothesis in science all the time. If something appeared to work because there was some other component then we can hypothesize its existence and test it. Sorry for my English
@@bmortomorton u stupid? His sentences make perfect sense, how do you come to your assessment?
@@bmortomorton fuck you! Everything he said was absolutely right.
The theory of gravity is incomplete and scientists can't agree on exactly how or why it does what it does.
However, the law of attraction is what we observe to happen, and it happens anyway because laws don't care if humans know why it works, it works anyway.
Well, yeah. Why, did people think it's weird and mystical? What seems weird and mystical is some results of some experiments, like the delayed quantum eraser. It poses hard philosophical questions about the nature of our, or any reality.
6:58
Nagative energy... First typo I have even seen :O
Must mean I'm paying attention
As soon as Dirac wrote his equation which worked perfectly but only if something else existed, programmers began to hurriedly patch the simulation to match it. 2 years later the anti-matter patch was released.
I mean this is kind of what modern physics is like... create a giant mathematical monstrosity to explain some discrepancy in your latest measuring devices, and then wait around until your monstrosity is "confirmed" by data from outer space or some blast at a collider. I'm not denying the reality or accuracy of physics, but it is in part self-generated by humanity and tautological. Spacetime and QM are just models at the end of the day, we participate in what is 'true.'
You just blew my mind. Seriously.
Just remembered why I'm subbed to this channel. I love this stuff.
I'm just going to appreciate your name
I also appreciate Hispanic Girls Twerking.
It is its own particle and wave!
Now I can't stop thinking about it. Ahhhhh!
Yep. My favorite on youtube.
I like how he says “unpronounceable username” but that doesn’t stop him from trying anyway🤣
This is the first time anyone has explained how artistic the Dirac equation truly is.
It's beautiful.
This channel is becoming PBS Quantum. Not complaining, I think it's actually cool!
Just as I suspected... fidget spinners are everywhere, even at the quantum level.
Minh-Tuan P i am offended!
so this is how the world ends...fidget spinners DX
Minh-Tuan P They are coming for the macroscopic world now! Quantum fidget spinners propagation!
Matt. I'm a huge fan of this series. It's really one of my favorite things to watch. I'm a 31 year old psychologist and I probably would have gone into physics had I a greater propensity for difficult math. What I love about your series is that you make complicated topics digestible for laypeople without dumbing them down at all (i.e., you do not insult our intelligence at all). I can also tell you are heartfelt and passionate about what you do. I must say, however, that in this episode I was a bit lost. I miss some of the earlier episodes when you really laid the groundwork for fundamental topics with rich graphics and detailed descriptions. Regardless, I remain an avid viewer. Thanks, and I look forward to future episodes!!
Also, this was the first time he said "space time" at the end meaning it as a name, the name of the show, rather than literal and punny space time.
I love how Space Time keeps it real and is not afraid to speak science.
6:57 “NAGATIVE ENERGY”
I don't know what to say but... thank you.
lul
Used by Nagas exclusively
6:57 NAGATIVE energy!?
Copydot I knew I couldn't be the only one that saw it!
My wife's got plenty
A hand for Bacicot! He'll be here all week, folks
Apparently it has something to do with snake people.
stop posting nagative comments plz
This is the FIRST TIME despite asking many knowledgeable people, someone has successfully explained to me in detail the inherent incompatibility of General Relativity and Quantum Mechanics. THANK YOU!
He hasn't explained that though.
He has only mentioned special relativity.
Came here after watching a flat earther video.... Needed to get my head back in order.
Flat earthers are like electrons. They aren't all there.
Jared Peterson me too!
Amanda, neither are you. I hope you don't enter the field of science.
You may have discernment but you lack imagination.
fntime r/gatekeeping
I,m amased you could find your head after one of these sessions. I Saw an avertising about flat earthers : see this all around the Globe . Stil LOL 😊🎸
This is why I love this channel. Most Physics channels explain things in basic ways. This is more friendly to those of use who like the more advanced explanations.
13:11 I don't know why, but him saying "Unpronounceable user name" and then seeing the user name made me laugh so much.
Please, please don't stop giving book recommendations!
I highly recommend the following books and CDs.
The Feynman Lectures on Physics, 3 Volume Set, The New Millenium Edition.
Important: The accompanying Feynman original audio in CDs are available. Expensive, they are packaged in sets of 2 volumes of 6 CDs each = 12 CDs for $120. There are 20 sets.
If you can afford the books and the CDs, then you can listen to Richard P. Feynman deliver his lectures AND read along in the books, word for word.
With headphones on and books in front of you, its almost like being at CalTech in 1961 with Dr. Feynman standing 6 feet in front of you.
I'm on my third complete read and listen.
Plus, there is an accompanying "Exercises for FLP", which contains all the exercises worked. The FLP 3-volume set, accompanying audia, and worked exercises is a physics gold-mine.
A skilled lecturer you are, sir, telling a story in an interesting way and keeping us glued to the screen waiting to hear more
Finally, Quantum Field Theory is coming! I've been waiting for this!
Finally, someone dose the Dirac equation justice.
yeah😇😀new episode. was waiting long for it
Hii bhai india se ho
Really good episode - I appreciate including the history of discovery behind these concepts as well.
Thank you for explaining the Dirac's equation in just the right amount of detail. So rare to watch a popular science video that's not completely dumbed down!
you guys totally should work on having closed captions
NO! It's always fun to see the auto generated one! I loved learning about the Dirac Sea!
You can always put the automatically generated one if you like. But by default the other is active
Louie Dubrow, Boo Schrodinger, Wolfgang Power Lee.... hahaha
I'm always left anxious to see the next episode. Always excited to learn more about physics. However, will PBS Space Time ever run out of topics? Can they continuously pump out new content without becoming too complex for their viewers? I love this channel because it keeps things simple enough for the layman to understand, but I fear that might also cut its lifespan short. :/
SirMikeys as long as people keep liking the content and as long as there are still new discoveries being made every day, this and many other channels will survive.
SirMikeys They haven't even scratched the surface, so you have nothing to worry about.
Philip True. They've barely even touched classical physics yet from the videos I remember (I've watched literally all of them so some I don't remember) which is far simpler than this obscure theoretical stuff. Plus they haven't gone that deep into relativity and quantum theory
ua-cam.com/video/ADIyIlO-_Ug/v-deo.html sorry couldn't help myself.
Excellent videos, love the way you break down these complex topics. Looking forward for more!
Once again I would like to thank such channels as this for providing such reliable info and amazing and inspiring video. I have learned so much watching PBSpaceTime. Keep it up
6:16 That moment when you realise that the two other states are antimatter and you feel so proud...
And then you realise everyone figured it out 3 minutes ago xD
Daniel Shapiro I thought they were talking about how electrons can have different chiralities, like left handed or right handed.
Only when they introduced the see of negative electrons did I get it was antimatter.
josh m You're actually right about the chiralities thing. That's the reason you need four components. Neutrinos have antiparticles too but they only need two components because they're always left-handed (or we thought they were, until SNO/Super-K)
I mean it's only in the title of the video...
on a side note can we agree that super kamiokande is the dopest name for a scientific experiment ever
"I thought they were talking about how electrons can have different chiralities, like left handed or right handed. "
Don't beat yourself over it, because you are actually right. The Dirac equation can be represented in many different ways, depending on the choice of gamma matrices. The choice found by Dirac, and the one described in the video, is known as the "Dirac representation" (also sometimes called "Dirac basis", but basis is not quite the right word). This representation makes evident the energy and spin states. There is another representation, known as "Weyl representation" or "Weyl basis", in which matter and antimatter states are scrambled but the different chiralities are evident.
You guys just made my Wednesday!
Your username is the actual best
The Strange Quark now there's an idea. We need an episode on strange quarks. There pretty much are no good videos on strange quarks other than the strange stars episode on this channel and Hank greens song(though that's not really what I'm looking for). Do they really convert other quarks into strange quarks when they interact? Where would all that extra mass(energy) come from. Are they only observed in particle accelerators? Could one spontaneously appear in a nucleus for longer than dictated by the uncertainty principle? Have anti-strange quarks been observed? Can we make predictions about the properties of strange matter in bulk with our current level of understanding? They are just so damn interesting!
Matt Long Do you follow the fermilab channel?
Some good stuff there.
+Matt Long I'll try to answer your Strange Quark questions:
Strange Quarks are the third type of quark, being heavier than downs but lighter than charms. Think of them as just regular quarks, the reason they are called strange is because they have an unusually long lifespan for a particle of their mass.
They do not convert quarks when they interact per se, but they are formed through the strong interaction causing other quarks to decay into strange quarks. The 'extra' energy comes from fluctuations in the strong force causing either energy from the surroundings (like in strange stars) to be used to form strange quarks or from the quantum vacuum, borrowing energy for limited period of time.
Yes they are only really seen in any abundance in particle accelerators due to the high energy surroundings but that's why strange stars are so interesting as they are a natural source of strange quarks.
Anti-strange quarks exist in equal abundance to strange quarks; when formed through the strong interaction both particle and anti-particle are formed and the strange quarks generally exist in a kind of Meson called Kaons (mesons with specifically a strange quark in them).
We actually know a lot about Strange Quarks as we've known of them since the 1950's. In terms of 'strange matter', strange quarks only last for milliseconds at best and to be honest they'd probably heavier than regular matter.
*Humpday
"A penny of antimatter could be used to launch a good size rocket into orbit."
I did a little math, just for fun. A modern 2.5 grams penny could, assuming 100% conversion of it's mass into kinetic energy, launch a 7428 metric ton ship to escape velocity. An old style 3.11 gram penny could launch a 9240 metric ton ship. That's assuming I made no mistakes. You might want to check those results ^_^
I checked, re-checked and checked again and you were correct
You are correct. I did the calculation myself.
It's not just the antimatter that becomes energy, it is the triggering matter as well. Therefore, when using matter to extract energy from antimatter, it could be a good idea to assume 200% conversion, not 100%.
that is true for both types of pennys... unless your mother is on board the rockets. you then would need to use quarters.
That's a lot of payload when you don't need to haul fuel!
I love this stuff, and I'm glad it's getting back to make simple stuff
What could make me more excited than finishing my exams for the semester? Oh yeah, a new Space Time video.
Who dislikes these videos? Is there a group of evangelicals who go around disliking science videos? That's the only scenario I can think of, because these videos are awesome.
r/atheism
Isaiah 53 John 3 it's funny how the smartest humans ever such as einstein, feynman, bohr are the silly ones, and the creationists of average intelligence are the ones who have it completely correct
Trump supporters.
Job, chapter 26, verse 7:
"He stretcheth out the north over the empty place, and hangeth the earth upon nothing."
www.physicsoftheuniverse.com/scientists_lemaitre.html
"Monsignor Georges Lemaître was a Belgian Roman Catholic priest, physicist and astronomer. He is usually credited with the first definitive formulation of the idea of an expanding universe and what was to become known as the Big Bang theory of the origin of the universe, which Lemaître himself called his 'hypothesis of the primeval atom' or the 'Cosmic Egg'."
A lot of "evangelicals" have been responsible for scientific discoveries. The dislikes are probably from people who want to believe that they are the center of the universe.
Faiyaz Chowdhury throughout history most of the scientists believes in god and gave their contributions to the science.... religion is not anti science.... if you think so then you don’t know the religion or god.... you are an another dumb ass militant atheist....
Completely fascinated by these series. Thank you very much!
This is video was great! One of your best. I'm glad I subscribed
10:02 Smooth coin flip without even looking!
How many trials it probably needed... Ah, just show us the bloopers! :D
God doesn't play with dice. However, Matt plays with coins. And he's a god at it!
I'm really curious to see how you guys are going to tackle QCD. Lordy, non-abelian gauge theories have never made proper sense to me.
Quantum chromodynamics from my understanding is colors not actual colors but a metaphor of colors which depicts the bosons leptons the force binding particles and it's virtual particles that pop into existence which is the better than a millionth of a second but it borrows energy from the vacuum and the more it borrows the last time it has to exist I have been studying Quantum Mechanics for 10 years and I feel like I truly do not understand the big picture but I did not go to college and I just have a GED in all honesty I feel like a dumb person sometimes but I try and that is sincere God bless stay safe
@@charlesdrury1587 I think you need the video on punctuation.
I suggest you invent a new theory to make QCD easier to learn.
I propose; something that really does not make sense, is because it is not true. For example, "dark" matter and "dark" energy have never made any sense to me. They are just words that people have made up to explain something that we do not completely understand. Antimatter, REPELS matter. To me, an idiot, explains both this 'dark' matter, and 'dark' energy bullshit. Perhaps that is just because I'm stupid....perhaps you are over thinking it.
@@charlesdrury1587 I have a theory that understanding it requires absolute divergent thinking. That it's more about connecting unrelated thought to crack it
One of the best episodes you've done! Awesome!
You, sir, give me hope for humanity. Keep up the awesome work. Love the eloquence with which you convey these insanely complex ideas.
I loved this episode! Mainly because I understood everything 😁
4:18 Screw with the fidget spinners, now I want a quantum spinner
Oh hey, it's spinning clockwise...Wait, no, it's counterclockwise...Did it just spin through that brick wall into the next house?
Spinor
There is something called a quantum rigid rotor.
Schrödinger's autism?
Auron's Waifu: What are you even talking about?
Well it's been a couple few years that I've been watching, listening and feeling these incredible "spacetime" informationals and honestly for a guy who does not know his multiple cation tables I'll often throughout my day reach outstretched fingers so to feel a vibrational tickling of strings and that practice has made tying my shoes a true joy. Thank you Professor 😊
Great episode Matt. Looking forward to your upcoming quantum videos =)
This video was so incredible, such complex concepts explained in such an elegant manner. You guys rock.
"And Quantum Field Theory... is a very deep topic."
I see what you did there.
And gods, I love this episode.
FINALLY, a more in-depth episode (since months!) and the foresight of more to come :)
Appreciate the efforts bro👍🏻
This is a great channel sir, I really appreciate the great efforts of the entire team to provide such great knowledge. Just a question, Have we found any proof(experimental) for the QFT or are we just dependent on the math.And also how do we know hat the Dirac sea doesn't exist. Thanks .
Ok, but pbs-space-time aint the only good sci-youtuber. Hope you know that?
brilliant
Brilliant. Awesome topic and direction. Keepin' 'em ALL on the run.
Great episode Matt with a great explanation , you helped me understand more about what Paul Direc stumbled upon and why, Cant wait for the next video , Im excited !!
But the question remains: why more matter than antimatter?
Does it matter?
ALL matter matters..
Rather, why is there more of one than the other, because of the anthropic principle. If antimatter had won out we'd consider that the "normal" one.
+MedoFortyTwo Well, maybe it did win but we still call it matter..
TimmacTR I love how often UA-cam comments ask very simple, reasonable science questions for which the best answer is "no one has any real clue."
When Dirac was at Cambridge, he had a visit from a French physicist. The French physicist had considerable trouble explaining his ideas in English. After struggling for some time in trying to explain his ideas in English, Dirac's sister came into the room a offered some tea, speaking fluent French. Dirac responded in fluent French. The French physicist then asked Dirac why he did not tell him that he spoke French. Dirac reportedly replied that you didn't ask if I spoke French. This anecdote came from a reliable source and gives some insight into this brilliant man.
That sounds more like a jerk/troll than a brilliand mind and I'd actually doubt that this ever took place.
@@hellegennes You're wrong. It was described in print by a reliable source. You're so rude, I'll not disclose the source. If you research it, you'll find the sources, but you're surely not capable of any real literature research.
@@robertschlesinger1342 Ok. Sure.
I love learning with you, you're a great teacher.
I think you nailed the writing for this episode. Great flow.
6:57 nagative energy = the energy that it takes to listen to nagging
Phenomenal, just in time for lunch!
Love that you're going to be doing QFT and such now. Awesome!
Thanks for the book recommendations Matt! You should do them at the end of every video on a subject you have a good book to recommend.
despite the constant negative energy covfefe
PlayTheMind We are all but holes in a sea of covfefe.
acapellascience : _carpe covfefe_ is my new mantra
PlayTheMind ok trump
Here is your award for best UA-cam comment of the week.
acapellasci
Great vid for real! Depressed that the Dirac Sea isn't real. What a crazy rad notion. Anyone know of any sci fi books or something that play with that idea?
I really appreciated your teaching pace.
Amazingly well presented!
When *Electrons* interact, and their *Quantum State* changes as a result of *Pauli's Exclusion Principle*, *how does every Electron in the Universe know what every other Electron is doing?*
That only holds locally. For example, different electrons in different hydrogen atoms can occupy identical energy states within those atoms. No problem at all.
Paul Dirac, Albert Einstein, Issac Newton and many others of which our generation knows and reveres nothing about. Truly it's a shame that this channel has less subscribers than supposedly good music artists.Leaving aside my diatribe, this channel is amazing.
achi329
agreed 100%
achi329 I'd rather have a channel filled with true seekers, rather than band wagon groupies. If learning about science becomes too "popular" then you can be sure that it will be filled with such people. It's like all the people who think wearing a pink ribbon is equivalent to caring about breast cancer. Keep the pink ribbon peddlers out of science.
@Philip I can understand your point but what I meant about popularity of Science increasing is the point that people understand why the method of Science stands the test of time. I want people to understand that when they look at a water bottle, their smartphones, their curtains, their homes, anything, it is a product of the scientific revolution, a tribute to the scientific method. People say God is everywhere. I say Science is everywhere...
I think it is a shame that a significant number of people are selfish assholes to others... we have many things in our culture that need fixing before love-of-science is imperative.
An Evolving Ape people do seem so narcissistic and hypocritical sometimes... they'll tell ya hey beauty is only skin deep and really not all that important, now excuse me while i go spend hundreds of dollars on beauty products and hours in front of the mirror lol
You are amazing. Congratulations. Keep up the good work!
The most useful channel on YT. Thank you for sharing knowledge.
It really says something about the way mathematics is woven I to the fabric of reality that someone can invent something to make an equation beautiful, then later find it in nature.
If you treat mass as the resistance to the change in time, what would happen? Would this mean anti-matter is actually relative time?
>>Reason for question below
There are a few issues. The biggest one I'd raise is that a point of infinite density or mass isn't proven science, PBS spacetime has done a video that points out the fact that it doesn't make much sense may be proof that we lack understanding in the same way the infinite energy density of the 'ultraviolet catastrophe' was proof that classical physics was wrong. In that case, no singularities.
The second is that 'infinite resistance to time' appears at a black hole's event horizon, this is the point where time seems to stand still when seen from outside the hole.
The third is that the same equations that suggest singularities say that there's a finite time you'll spend inside a black hole before hitting the singularity.
There's also issues with radioactive decay. If something can decay into something else with less mass, it will. The bigger the difference in mass the quicker the thing will decay. The electron's heavier relative, the muon decays in 2.2 microseconds, the tau, 10 times heavier decays in nanoseconds. If mass slowed time we'd expect heavier particles to be MORE stable, slowing their own decay.
Then there's speed and time; going faster slows time independent of mass. A proton moving at 99% of light speed has time slowed as much as a much lighter electron moving at the same rate.
E = mc^2
m = E/c^2
mass is in itself just energy and mass may just be a way that energy is materialized.
Imagine you were a particle in space and you emit an osculating wave of energy in all directions. Where 'you' are materialized is where the center of your osculation is. Now have an external wave interfere with yours. Parts of the wave may cancel each other causing them to shift the peak in one direction or another.
Treat that kind of effect as a fundamental force and try to describe them with it. The jumping you do, is just canceling the frequency of your existence near the earth causing you to appear farther away from the surface.
I do admit, it seems far fetched - but when you run into an impenetrable wall, you have to find a way around or over or under it.
So If I read you right in this comment you are suggesting that a particle of 'stuff' emits (Or is) a wave in all directions. Now when some other stuff is nearby their two waves partly cancel out so that the center of each wave is now at a different place and he two bits of stuff seem to have made each other move?
You and your team always do such a great job of framing and presenting the material. The accent is just a bonus!
This channel is awesome. To top it, every time you sound a Star Trek sound effect, it effects me as a Pavlov chime.
Schrödinger. Schrödinger. ÖÖÖÖÖÖÖÖÖÖÖÖÖÖÖÖÖÖÖÖÖÖÖÖÖÖÖÖÖÖÖÖÖÖÖÖ
xSimonTan ö= oooohw
(Lol idk)
in this episouauooode
Oh, so other languages should perfectly imitate the fronted vowel sound, but ~not~ the uvular r sound? You don't seem to care that he's pronouncing the -er completely differently than German would. Why draw the line there? Why not just tell him to speak the whole sentence in German? That's absurd. Names have translations too.
***** if names have translations why dont we read juan as juan
Bunny are you insinuating that I'm not aloud to read Juan in an English linguistique way?
wolfgang is the best name I've ever heard.
Not much of a Mozart fan then, maybe you will be now?
you are always helping me understand
Why haven't I found you're channel before! You sir are amazing 👏
"Imagine an infinitely deep ocean of electrons... that exists everywhere in the universe."
Sure, easy.
I know right. I wonder what that would be like. Oh the world of "imagination". Lmao 🤣
I studied chemistry with some condensed matter physics and I have been assured electron holes are a very real phenomenon and not just a mathematical trick. Intuitively they would move counter to electrons due to their apparently positive charge. However, according to wikipedia, they move with normal electrons because the highest energy electrons in a solid also have a negative effective mass due to quantum mechanics. Please help. 😭
Unfortunately, the names have confused you. The Dirac sea in relativistic quantum mechanics is not the same thing as the electron sea in condensed-matter physics.
There's a difference. One is a hole in SOMETHING, which is simple enough, the other would be a ole in NOTHING.
An electron hole, which must occur in a solid is an absence of an electron in what would otherwise be a near uniform 'sea of electrons'. This is simple enough, one can make an equivalent out of a bunch of marbles on a table. There are strict limits to them, for example you cannot make a 'double hole' by removing two electrons from the same point because there AREN'T two electrons at every point. There's also a 'graininess' to it given by the structure of the solid it's in; a hole tends to 'hop' from one atom to another rather than moving smoothly.
The 'dirac holes' however would appear in empty space and would be essentially unlimited. With enough energy you could make holes of any depth and charge and the dirac sea would be an infinitely deep ocean of particles at every single point in the universe which is a lot to assume just to make some math work.
I think this is easily his best presented and most well written episode.
i cant get enough this. i wish you guys post videos everyday
7:00 *Nagative* Energy
This episode made me wonder. QM is completely compatible with SR. So why isn't it compatible with GR? I mean, SR is just an approximation of GR for flat spacetime. What I mean to say is, SR is contained within GR. I mean, if something were compatible with Newtonian mechanics, wouldn't it be compatible with SR? So shouldn't QM be compatible with GR as well? Unless the math for QM requires spacetime to be flat? That doesn't seem very satisfactory though. Idk.
QFT is actually more complicated than he let on -- which, to Matt's credit, he indicated, and I have no doubt he'll clarify the issue in future episodes.
Early on when people tried to compute relativistic corrections to common quantum processes, they expected an answer that would be, you know, negligible at small energies just like we can ignore special relativity when driving a car. What they found instead was "infinity". QFT correction to electron mass? Infinity. QFT correction to electric charge? Infinity. QFT correction to the decay rate of positronium? Infinity.
This was quite vexing until it was found that physicists were taking their equations too seriously: we defined the theory assuming it would be valid at all energy scales. In reality, there's no reason to assume that, and we have no doubt that at higher energies the standard model will be replaced with something else. So we came up with a scheme for ignoring high energy physics that we don't know, and focusing only on low energy predictions that we can control. This procedure, known as "renormalization, allows one to get rid of the embarrassing infinities and get sensible results to the simple calculations I mentioned. The price you pay: for each infinity that you remove, you must include in the theory a parameter that you cannot calculate, but only measure from experiment. This is fine -- this number represents all the high energy stuff that you ignored, and it would be very surprising if you could get away without needing experimental parameters!
For the standard model this works beautifully, and you get a theory that can be written in terms of a few dozen parameters that you have to measure. However, this can't be done with just any physical theory. In fact, only a very small class of theories is tractable in this way. For the rest, when you try to do this, you end up playing a game of whack-a-mole: you get rid of one infinity, you end up with another. You try to get rid of this other, and get another one still. At the end of the day, you had to include an infinity of experimentally determined parameters, one for each infinity that you removed, and your theory ends up useless. It has no predictive power whatsoever.
General relativity is a theory of this type. You can try to do quantum mechanics with it, but the infinities pile up on you and you get nowhere.
Sir, excellently said.That was the most eloquent description of renormalization I've ever heard.
I'd also like to add that, while physically we certainly expect new quantum gravity effects to come into play at high energies to change the physics, mathematically speaking a renormalizable theory can be extrapolated at high energies, barring other types of inconsistencies that need an exact, non-perturbative treatment to be studied.
In an even more mathematical sense, what I've found is that the reason why renormalization is a feature of QFT (and not a bug, of course) is that at a foundational level one has to deal with operator valued distributions. And using distributions can essentially be reformulated in the Wilsonian sense, introducing some kind of cutoff to do coarse-graining with, without being ever able to lift it completely, only pushing it higher and higher. Analogously as how distributions can act on functions with arbitrarily small support, but never on delta distributions. This is related to the no-go theorem on products of distributions. I find this perspective fascinating because in some sense a rigorous formulation of the QFT axioms naturally lead to some sort of intrinsic fuzzyness for the physics of these objects.
Well, "renormalizable" is not quite the same as "UV-complete". Your typical U(1) gauge theory is renormalizable but not UV-complete because of the Landau pole (which is what I think you meant when you said "other types of inconsistencies that need an exact, non-perturbative treatment to be studied"). Indeed perturbative-ish conclusions must be handled with caution even in theories which _are_ asymptotically free, but the Landau pole makes this mandatory. Unfortunately, to my knowledge there has not been enough progress in this area that allows one to make the determination of whether or not QED makes sense at high energies (at the physicist's level of rigor).
Even finite theories require renormalization, if simply to write down the dictionary between parameters in the Lagrangian and measurable parameters. Coleman's example of a ping-pong ball in water is relevant: when moving a ping-pong ball through water, some water sticks to the surface and the "effective mass" is much higher than the "bare mass". As such, the basic idea of renormalization doesn't seem to have anything to do with the subtleties of distributions, though the technical requirement of renormalizability certainly does. But then we must distinguish between the basic idea of renormalization and the regularization of loop integrals, which is what the problem in quantum gravity is ultimately about anyway.
The Landau pole is indeed one of the things I was referring to, yes. But I'm very skeptical of its existence. There are papers attacking the strong coupling asymptotics of the beta function in QED and other theories, suggesting its absence.
Coleman's analogy is very relevant as a conceptual physical understanding, but the mathematics of the distributions one has to use in QFT actually implements renormalization in the theory from the very start. It is when one makes the mistake of not using distributions that the need of setting up the whole regularization --> RG process comes about; this formulation is essentially fixing the mistake that one makes in the beginning. But making the mistake and then fixing it is actually easier, so we do it all the time. The mathematical reason behind the appearance of renormalization is subtly built into the axiomatic framework of QFT, but was discovered differently and finally understood in a consistent way with the basic physical idea behind it. My point is that this idea is reflected by the need to use distributions, and this can be checked explicitly (at least in simple cases). The need to use it to make contact with measurable parameters is also there, but that's outside of the formulation.
A different issue is non-renormalizability, which should be traceable back to a theory that fails to satisfy the QFT axioms fully. It's hard to prove existence even for simple renormalizable theories, sadly, so it's not surprising. In the 'make the mistake, then fix it' perspective this reflects in the issue of loop integrals and so on, so one is unable to get to the 'fix it' step. But this is an incomplete way of looking at it. Recent works in asymptotic safety suggest that maybe there are theories which are 'non-perturbatively renormalizable', and GR might be one of such theories. But in principle it may not be UV complete, yes.
This was a particularly clear and insightful episode. Can't wait for those upcoming QFT videos!
This is the best physics channel on UA-cam. Just can't say that enough.
Schroedingers fidget spinner
Until the fad is over, Schrödinger's Spinner is both innovative and uninspired simultaneously.
S A D B O I quantum fidget spinner
7:00
oh boy we get to see how wrong that episode of evangelion was
Actually, Evangelion stayed pretty faithful to the idea behind the concept; "falling" into a Dirac Sea in Evangelion is essentially shifting beyond humanly observable reality and entering the seemingly endless deeper reality beyond it, one comprised of thought and emotions opposed to the physical realm - a reverse of life as we know it, from which of is incredibly difficult to navigate yourself back from.
Obviously it isn't an exact parallel to the actual theory, but the idea of an endless ocean beneath the ripples we see from above, and the forces within such an ocean being antithetical to the forces beyond it, are similar in concept.
Only a solipsist would believe that physical reality is a product of thought and emotion, rather than the other way around.
Solipsism isn't necessary. Such an extreme judgment of others isn't necessary. Google "causal emergence".
This was a very interesting episode, can't wait for upcoming episodes on QFT!
I really do think this is one of the best videos I have ever seen on UA-cam.
02:40 "that doesn't mean that they are actually rotating". Say what? Angular momentum without any kind of rotation? You better check on the definition of angular momentum bruh. I would love to hear an explanation of your explanation in a future video. Love your show, thanks!
Ah, that was what physicists first thought when they discovered electronic spin. Please see the Stern-Gerlach experiment. However, they soon realized that in order for an electron to have the observed (intrinsic) angular momentum, plus or minus h-bar/2, its surface would have to rotate (ten times) faster than the speed of light. Thus spin is a measure of angular momentum with no classical counterpart.
Tue Le electrons don't have a surface
Musky Elon angular momentum definition: the generator of rotations.
Aeroscience, I'm talking about the classical electron model due to Lorentz, in which you can either envision the electron as a homogeneous sphere or ball of charge, whose radius can be calculated. The fact that an electron's surface would have to rotate faster than the speed of light indicates the inadequacy of a classical description. Thus, spin is a measure of angular momentum with no classical counterpart.
They don't actually spin but they have similar effect and property as an angular momentum.
Spinnors
Fidget devices.
Fantastic channel!!! I hope you guys will keep up the great work!!!
This channel is awesome, thanks guys.
If I have a quantum field in my backyard, can I plant flowers in it?
Yes, but they'll both grow and not, at the same time. Don't look or they could vanish!
If photons have no mass, why are they attracted to black holes?
The black holes have mass, and that mass warps spacetime, and the photon is travelling through that warped spacetime, and it has to conform to the warped spacetime geometry, which is why it is attracted to the black hole.
Because it has energy I think.
I think waifu is right
Photons have no rest mass imparted to them by the Higgs field, because they don't interact with it. They do have energy, and by E=mc2, they therefore can be treated as having mass proportional to that energy.
However, that doesn't mean that they are "attracted" to black holes. A photon moving through spacetime will, from its' perspective, move in a straight line. Since the spacetime it moves through can be curved by gravity, large gravitational fields like a black holes will change the curvature of that spacetime, so that an outside observer (like us), would seem to see the photon be attracted to the black hole. The reason a photon can't escape an event horizon is that even c isn't fast enough to "climb" the curvature of spacetime beyond that point, not that it is attracted to the singularity per se.
Best answer.
Thank you for sharing this that was very interesting.
Never been disappointed being subscribed to this fabulous channel!