The importance of the Dirac equation | Cumrun Vafa and Lex Fridman

Lex Fridman Podcast full episode: • Cumrun Vafa: String Th...
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Cumrun Vafa is a theoretical physicist at Harvard.
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[@aXw4ryPlJR]

You can’t invent history by imagination. Dirac noticed the negative energy himself and tried to interpret it, not that other physicists pointed out to him. He did get nervous about announcing his antimatter hypothesis, however never considered the negative energy solution a mistake. After he made up his mind he never retracted the final antimatter idea, even under constant mocking by many including Bohr, until the verdict came from Anderson’s observational discovery.

[@aXw4ryPlJR]

“A hole, if there were be one, would be a new kind of particle, unknown to experimental physics, having the same mass and negative charge to an electron. We may call such a particle an anti-electron.” Published by Dirac in mid 1931 - the greatest prophesy in modern theoretical physics - prior to actual experimental discovery

[@satnamo]

@@aXw4ryPlJR the best of man is he who has eyes to see the unseen because seeing the unseen is enlightenment

[@thlee3]

its crazy to me that they took pictures at this level in 1932

[@scienceontheright]

This is why I am enraged when people say there's a consensus of scientist who claim "_____", fill in the blanks. They do this with Dark Matter, Covid or Climate Change. And if you suggest something different, or try to poke holes in their ideas, they mock you and call you a denier. Science should be questioned. Always. That's an essential part of Science. And Science should never be about consensus! It should be experiments, results and the DATA.

[@scotthumphrey6477]

"Dirac noticed the negative energy himself" . Yes he did! Thanks for pointing this out.

[@stephen20105]

Dirac is the most under appreciated genius in history

[@M.-.D]

Very appreciated by physics enthusiasts but I agree the world doesn’t know of him. His time will come like Tesla and Turing.

[@gaulindidier5995]

@@M.-.D Tesla should never been in a conversation with Dirac and Turing.

[@niks660097]

@@gaulindidier5995 Tesla was an engineer, without engineers physicists are stuck, which is the current problem with "bigger" particle accelerators...

[@gaulindidier5995]

@@niks660097 Yeah sure, Engineers are very important, but they can't go to abstraction land like Grothendieck or an ex engineer mathematician, Raoul Bott. I most probably could never start to build the LHC, and probably would make everything explode...

[@ayushdhingra855]

@@niks660097 vise versa also true

[@pedroricardomartinscasella641]

One of the things I believe is amazing is how two of the greatest physicists in history (Mr. Feynman and Mr Dirac) had such different positions about the field they worked on. While Feynman believed strongly that we can only consider a theory when there is consistency with experiments, Dirac had an almost religious view on the mathematical beauty and simplicity of an equation. He even said that a beautiful equation is more likely to be right than an ugly one with consistency with experiments.

[@areebhussain321]

thank you for this

[@koho]

I vote Feynman

[@audience2]

I vote Dirac

[@theboxingbiker]

@@audience2 I vote Dirac too Excerpt from the book The Strangest Man " In his paper, Dirac had cryptically remarked that a critical quantum quantity is ‘analogous’ to its classical counterpart, but Feynman believed that the correct phrase was ‘proportional to’ (that is, if the quantum quantity changes, the classical one always changes proportionately). Here, at last, was Feynman’s chance to find out what Dirac meant. Feynman described his problem to Dirac and came to the crunch: Feynman: Did you know that they were proportional? Dirac: Are they? Feynman: Yes they are. Dirac: That’s interesting. Dirac then got up and walked away. Feynman subsequently became famous for his new version of quantum mechanics but thought the credit was undeserved. The more closely he looked at the ‘little paper’, the more he realised that he had done nothing new. He later said, repeatedly, ‘I don’t know what all the fuss is about - Dirac did it all before me.’ "

[@ferrantepallas]

beauty is in the eye of the beholder ... who's to say what is ugly? Beauty and symmetry can be misleading in physics -- where is supersymmetry now?

[@circuitbreaker8314]

man this guy explains this stuff in so easy language this guy is a genius

[@alwaysfourfun1671]

This very pleasant conversation diminishes Dirac's brilliancy in not only deriving the Dirac equation, but also interpreting the "negative energy states" and "anti-matter", as I remember it. That Dirac felt unsure about the mindblowing leap in insight just goes to show how revolutionary the ramifications of his equation were.

[@RonPaulKicksAss]

Wave-particle duality kicks ass! Love the show!

[@kayligo]

I hate when I accidentally create negative energy

[@rogerthornhill1491]

Just change your orbit and problem solved.

[@RajeshYadav-to5zq]

You can come to my orbit 😂😂😂

[@areebhussain321]

@@RajeshYadav-to5zq the sheer game physicists have is demonstrated through your comment

[@haroonrasheed3844]

😂😂

[@mauriciofurlan7773]

Obrigado por terem colocado legendas em português neste vídeo sobre Paul Dirac. Excelente entrevista sobre a obra deste brilhante físico. Um abraço,!

[@andrewbogle3350]

Graham Farmelo’s biography of Dirac ‘The Strangest Man’ is a good read. He really was strange as well as a genius.

[@BarriosGroupie]

Lex asks great questions, such as here about how great a leap it was in viewing particles as fluctuations in a field so that for an electron, there's an electron field. It's a fine lesson in never being afraid to challenge conventional thinking with newer, more elegant ideas to replace it.

[@rossfriedman6570]

Someone explain the first and second derivative of the time operator thing he talks about in the beginnjng

[@Drbob369]

Good work

[@deepdrag8131]

Dirac was one of Feynman’s heroes. When they finally met, the notoriously shy Dirac found Feynman’s extroversion and enthusiasm unbearable. They never spoke again.

[@nicolaparsons5703]

Strings finding their way home

[@stephen20105]

Go noles!

[@pussiestroker]

"A particle (positron) which goes in the opposite direction that the electron goes when there's a magnetic field" Are these positrons on the same orbit as the corresponding electrons? And where are they situated when they are not under the influence of a magnetic field? Thanks!

[@PhilFogle]

The positrons were not in orbits but were free particles created in electron-positive pairs by cosmic ray collisions. Under these conditions, positrons and electrons are deviated by magnetic fields in opposite directions.

[@KaliFissure]

Both of the solutions are correct. Every electron is a positron on the other side of time

[@captainjack_sparrow2391]

Dirac was a legend who founded Quantum Mechanics , one of the genius of 20 th century, how these people will assess him?

[@clmasse]

No, the quantum field theory was first developed by Pauli, Jordan, Dirac and some others, as soon as 1927. To be complete, the idea was already in the three man paper (Heisenberg, Born, Jordan) in late 1925. Feynman provided only a perturbative way of calculation. Too much is ascribe to him because of the economic power of the USA.

[@narayankhanal9662]

❤❤❤❤Love this

[@mathunt1130]

I've not heard this history before, it was an interesting perspective. Maths is always cleverer than the user...

[@derekbentley334]

Wondering but knowing the how.

[@herbertsiegl7762]

Well...i have to take his word for it...

[@guygordon2780]

The negative energy solutions are *NOT* positrons. Positrons clearly have positive energy. When electrons & positrons annihilate, they produce 2 x mc^2 energy. Also, positrons do not fall up. They could simply be artifacts of not handling particle creation and annihilation.

[@Random_Tangent]

Negative energy is a thing? So antimatter is a thing.. but not antitime?

[@manojmadanagopal8441]

what a guy! has a story to say physics.

[@timetin]

To what extent leaps of faith.

[@ruandav6823]

Holograms are a great example of particles fluctuating in a field. Technology makes it possible to bend the field. Think about it next time you microwave your boxed dinner 📡

[@seymourfroggs]

More words made up by Vafa than Dirac ever spoke.

[@youtoober808]

I don't understand a dam thing he said

[@indicaedits8692]

🤣🤣

[@someonesomewhere8325]

Hahahaha. Yes

[@mauriciofurlan7773]

Poderiam ter colocado legendas em português. É somente para os ingleses e americanos? Que pena!

[@sergiolucas38]

Aprende ingles cara, vai deixar de se comunicar com o mundo por causa disso? boa sorte.

[@Aluminata]

Did Dirac not know a proton is 1800+ times the mass of an electron?

[@michaelborek378]

Dirac and his equation is proof that Gods walk among us

[@satnamo]

Man is a good in ruins

[@paulkestyn518]

Hey, I didn't give anybody permission to take my lane.

[@angelamusiemangela]

😊😘

[@pierrebernard5922]

Dirac showed that empty vacuum can borrow particles from the futures They will meet and destroy themselves

[@AkamiChannel]

They aren't entirely destroyed because they create a lot of energy when they collide. You can view them as being converted into energy (photons iirc).

[@KrossFire330]

Yes, matter-antimatter collisions produce energy through a process called annihilation. When a particle collides with its respective antiparticle, they annihilate each other, and the total mass of the two particles is converted into energy according to Einstein's famous equation, E=mc^2. This energy is typically released in the form of gamma rays or other high-energy particles.

[@viktorbajo4382]

Be very careful with such statements. I'm sure you are talking about virtual particles, the thing is, that it is a ''mathematical trick'' or our explanaiton/description of vacuum fluctuations. Particle-anitparticle pairs emerging from vacuum and then anihilating while giving borrowed energy back to vacuum is just a simplified interpretaion to wrap our minds around certain problem. The reality (whatever your definition of that is :D) is very likely different and probably beyond human imagination. Physics is not about describing reality, it is about creating models of the world which are consistent with our observations.

[@jaahigafiscaa]

Trae young lol

[@cbrg870]

That was my first thought lmao I was so confused

[@thedouglasw.lippchannel5546]

"I Have Become Space" - Silly isn't it. Rate of motion changes matter. It's a particle when "stopped" and a wave when in motion. See CIG Theory. An introduction is on the link above. But, since I am not a trained physicist, I need the help of the community to further its offerings. HELP

[@david-joeklotz9558]

Imagine that! Dirac discovered reality mathematically, BEFORE the reality was proven to exist! Absolutely incredible 😎 So, it is conceivable that taking the Schrödinger equation at face value, the Many World’s Interpretation of quantum mechanics, by Hugh Everett, may just turn out to be correct ☺️

[@clmasse]

Mathematics shows where there is an inconsistency, and force to bend the reasoning. It predicts nothing by itself, it only guides a good initial idea.

[@david-joeklotz9558]

@@clmasse It LED Dirac to the positron.

[@brb4903]

yeah but Dirac came to the equation that bears his name by calculation, Schrodinger got his equation out of his belly.

[@deepdrag8131]

Dirac had his famous equation inscribed in his gravestone.

[@jamesjarvis-bx3qi]

It's 1-0 on that equation because there is a square root.

[@jamesjarvis-bx3qi]

Schlodsinger is interesting.

[@drbonesshow1]

Sounds like these guys are rewriting history. I like the facts not the fiction.

[@MrBLAA]

it must be nice, to be wrong... and just make up a solution to show why you're not🤔

[@kreglfromworld]

He wasn't wrong, he was just incomplete.

[@nunyabusiness8498]

If anyone was wrong it was Schrodinger, Dirac's equation was very accepted by the physicists of his time and has been by modern physicists.

[@David_7171]

And of course positrons are used in all major hospitals in the form of PET scans

[@diaryofacrankykid7270]

I wish Lex had stuck to these topics and not platforming science charlatans like RFK...

[@raymondingram2539]

It's funny how most people have heard of Einstein but not a lot of people have heard of Dirac, I think he disserves more credit.

[@jamesjarvis-bx3qi]

Telepathy = CRN1

[@jamesjarvis-bx3qi]

To use telepathy use your throat and tongue chakra. Moving your tongue to sound out the words helps transmit.

[@loisruane2636]

I absolutely love your show and I wish you were on Odysee. I’m deleting KZbin so I am about to leave. We must fight these companies that are censoring. I will really miss you!

[@ryankylecross]

That's a bit dramatic

[@Apocalymon]

Soooo melodramatic. Good luck, no one will miss you & Google has shadow accounts on people without one.