One of my favorite thinkers in the world. Few people of such vast intelligence are able to explain very abstract things so lucidly and understandably.

One of physics best speakers these days. So clear and direct. More people need to be exposed to these types of topics and Sean Carroll provides a great place for minds of all intellect to join in and learn more about the world around us.

People like Sean Carroll made me interested in Quantun Mechanics. The way he explain everything makes you love all the stuff about physics. His books are great and everytime i re-read them i learn something new.

Carroll brings to the masses an understanding of QM that allows you, the non-physicist, (but perhaps a philosopher) to better think about reality from the micro- to the macro-realm and that Emergence is the operative term. Emergence addresses the transition from the fundamentals up to and including spacetime. Carroll is a master communicator whether you accept what is rather easily understood from hearing or reading from him or not.

Hugh Everett even visited Copenhagen in order to meet with Niels Bohr, the "father" of the Copenhagen interpretation of quantum mechanics. The visit was a disaster! Everett's idea that the universe is describable in objectively existing universal wave function (which does not "collapse") was simply a heresy to Bohr and the others at Copenhagen. The conceptual gulf between their positions was too wide to allow any consensus. Léon Rosenfeld, one of Bohr's devotees, even described Everett as "undescribably [...] stupid [who] could not understand the simplest things in quantum mechanics". Everett later described this experience as "hell...doomed from the beginning."

Sean Carroll's hair is in superposition between clean cut and wild theoretical physicist

Sean Carroll is my favorite living physicist, ainec. I can not wait to get my copy of his latest book ‘Something Deeply Hidden’! From my view on the sideline as an amateur philosopher of science, I believe Professor Carroll is near the goal line, and will make it into the endzone. What a great day it will be to finally spike that quantum football!

To hell with emergent gravity. The encased microphone in a foam cube is the most brilliant thing I have seen in a long time.

Sean Carroll provides the best explanation of quantum mechanics that I have seen to date. He gives a quantum mechanical explanation of curved space-time and vacuum energy. He idea of not attempting to quantize gravity but rather to start with the Schrödinger equation and deriving quantum gravity is unique, as far as I know. I especially like the fact that he's a devotee of Hugh Everett's Many-Worlds interpretation of quantum mechanics. I'm a member of a book club that will be reading his book "Quantum Worlds and the Emergence of Spacetime."

Amazing! This is the best explanation of a concept! He always repeated the same sentences in different talks, but only now I finally got it! Over time he perfected the way to explain it to other people!

This guy's the best. Loving the videos and loving the book, whose every chapter I have to read at least twicel

Heisenberg, Schrodinger and Ohm are in a car They get pulled over. Heisenberg is driving and the cop asks him "Do you know how fast you were going?" "No, but I know exactly where I am" Heisenberg replies. The cop says "You were doing 55 in a 35." Heisenberg throws up his hands and shouts "Great! Now I'm lost!" The cop thinks this is suspicious and orders him to pop open the trunk. He checks it out and says "Do you know you have a dead cat back here?" "We do now, asshole!" shouts Schrodinger. The cop moves to arrest them. Ohm resists.

Very much liked the final section where Sean suggests an approach which brings together entanglement, quantum field theory and gravity. I'm really looking forward to theoretical and practical developments with this idea.

I absolutely love Sean Carroll. He can explain very difficult concepts in laymen's terms which is very difficult.

The first half was an exceptionally good summary of the eave-particle dilemma. Really enjoyed that.

14 minutes in and my admiration for this guy has increased dramatically. Why haven't I seen this before. It strikes me as the most honest and articulate description of the subject (for the average guy) I've come across. Show this to your physics class.

At night I’m half awake and at day I’m half asleep. Superposition!

Excellent presentation. I've always thought the "many worlds" interpretation was a cop out but Sean's explanation here has opened my mind to this. Just bought his book. Also, I always felt that Einstein was right when he said that QT's Copenhagen interpretation cannot be a true desription of reality. That whole particle / wave duopoly message and "just accept that's the way it is" always seemed daft to me but I've just assumed that these physicists know what they are talking about so who am I to judge?

The very best video I have seen on this topic. I'm merely a "shade tree" scientist these days (ex-electrical engineer) but this makes(mostly!) a lot of sense. I was fortunate in that I had many great profs but very few were communicators of this caliber.

Sean is a Real Revolution, an observer with unmatched potential and traits, a teacher beyond ordinary human potential who justifies his teaching traits with exact knowledge or research work original to himself after testing it thoroughly and above all he is open to feedbacks to rectify errors as well as stay humble with appreciations. He just Rocks Physical science. Thank you Sean ! for all your research in scientific domain. Lots of appreciation for your originality. Hemal Bhatt

This talk explains the anomolies in the double slit experiment in the clearest terms yet. Great talk.

As soon as I see a new lecture from Sean , I immediately click.

Amazing talk. Again. How is this man so consistently mind-blowingly well-articulated? _...what am I doing with my life?_

Brian Greene and Sean Carroll are the best physics lecturers I have ever listened to.

Wow, he is such a communicator ! Respects !

I really liked this talk. Several times I thought "Of Course!" - the idea of having only the Universal Wavefunction and deriving from that the rest of the world, including gravity, is such a beautifully simple/elegant theory. Thank you!

Thanks for this talk. It's great you show the speaker 99% of the time because we would totally not know what he looks like otherwise. On the oth we can always get access to his slides easily and there is nothing special about one slide from the other. I just love watching a speaker speak.

I like this. I remember watching Krause years ago and being impressed and I got the same feeling now. Might get the book (from the library)....

As far as I'm concerned, Everett was right. Universes are made of particles, reality consists of multiple universes and the wave equation tells you how universes are related to each other over time. When you make a measurement, you get some information about which universe you are in. In other universes, other copies of you will make different measurements and learn something about which universe they are in. Did I misunderstand anything?

Wow. Once again, Sean finishes a lecture and all I can say is wow. What a great explainer. He makes the subject so simple that even a being made of quantum fields can understand it! As an engineer, I'm used to thinking of classical mechanics: balls rolling down hills and trains going different speeds. But now, quantum physics says, "Forget classical mechanics. Don't picture balls, trains, particles, bullets, atoms.They went out with Newton (and way back to Aristotle). Think of FIELDS... ripples on a pond. Forget the stone that caused the ripples. Just look at the waves in the water." So now I think of the world like trillions of ripples. You and I give off ripples in space and time. The Earth gives out lots more ripples. The reason I stick to the Earth is not because a force is pulling me down, but because the Earth gives off many ripples (waves) than I do and they distort space. That distortion is what we call gravity (which we can't see happening!). Anyway, I'm picturing the universe differently now. I don't see particles... I see waves aka ripples. Extrapolating, where enough waves meet at a given point, they act like a solid particle. But the wave came before the particle. How am I doing, Sean?

'Something deeply hidden'....is excellent attempt towards closer to reality (Truth)... presentation by Dr Sean Carroll is really beautiful.... thanks 🙏

Absolutely fascinating talk! Thanks for sharing!

Working through the book. I find it understandable but maybe I’m biting off too-large chunks too infrequently. This lecture helped me refresh and reprocess. And for the love of cats, don’t read the comments on this video.

A Higgs Boson walks into a church and the priest runs up and says "Thank God you're here, We just couldn't have mass without you".

For a reason I haven't yet pinpointed watching this really made high level quantum computer understanding click and make sense!

Sean is a true genius of our day and a very good communicator. You have to listen, even if you disagree. I find it very hard to disagree with Sean.

Gary shandling knows a lot about physics!

Sean is a great explainer. Loved the entire talk!

This was awesome thank you so much for this great presentation

Well put. Easy to follow (for me) and I am a social scientist…. I am looking forward to 1) if it changes our view on the universe we see. 2) If there will be any way to prove it. I do love the emergent gravity that comes out of it. Susskind is on the same path, I saw in one of his videos.

Sean is always a legend but here he was in motherfucking GOD MODE! damn.. such a legit talk

I LOVE QUANTUM PHYSICS! Jake 7 from UK

It is interesting to see determinism and chance at a cross roads in many worlds. The possible paths are all set but your journey through life take turns you may influence.

Very clear and interesting speech. The ideas he talks about seems very natural and at the same time very mind blowing.

This is million time better than sci fi movie. Nobody can write a wired intresting and spooky story line like this

‘That’s just too many universes! Sorry I don’t like it!‘ 😀 Like this.... love his talk show, Mindscape, also.

Great lecture by Sean Carroll ! 10 hyper giant blue variable stars ********** Nice explanation of Everett's Many Worlds Interpretation of QM...as well as a clear discussion of the inherent fallacy of Niels Bohr's Copenhagen Interpretation of QM. Thank you.

What a brilliant mind...so open and accessible...

Sean Carroll is clearly one of the greatest modern day physicist and ambassadors of quantum theory of all time!

Love what he’s preaching man. Let’s get to the bottom of this, not just calculate. Rock on

What an awesome talk? Love his style...

1. Entities in a superposition are in a superposition of well-defined states. (Spin up / down, cat awake / asleep, electron located here / there.) 2. Entities in a superposition don't experience that they're in a superposition. (They experience that they're in a well-defined state. Because they *are*. Just more than one of them.) 3. The states that are superimposed never interact. (The awake cat and the asleep cat are separate worlds.) 4. Entangled entities experience each other as well-defined. (They're in one collective superposition. Measurement / observation is just entanglement.) 5. Decoherence is when an entity is entangled with the environment. (Where everything experiences everything as well-defined.) The worlds of the Many Worlds concept are the individual states of the superposition. The apparent collapse of the wave function upon measurement is the entity becoming well-defined to us when we become entangled with it (#4). What really happened was its superposition still exists but now includes us.

"What's in the box?" - Brad Pitt, 1995.

This is the version of Sean Carroll convincing us to believe the many world interpretation. I would rather watch the version of him explaining how the Copenhagen interpretation was correct, i.e. in another world.

This is so mindblowing that it's crazy but also crazy reality!

Quantum physics has hit a fracking brick wall.

One thing that always bugged me about the shröedingers cat thing is.... Isnt the CAT itself an observer? Isnt the microscopic bacteria on the glass vial, observers? Isnt the quantum fluxing virtual particles popping in and out of existance, occasionally colliding with the transistors in the sensor that triggers the hammer, also collapsing the wave function as they interact, however minutely, with the system? The universe itself doesnt require a human or robot to observe a state, the universe observes itself, continually, constantly. You already touch on the fact that its not wishy-woshy conciousness that collapses the wave function. So then, why dont we consider the CAT in the equation? It itself surely knows what "state" it is in, if its dead or not. Thus, the outside measurement is irrelevant, because the wave function collapses as soon as ANY "event" takes place, as soon as the cat dies, or doesnt die, the wave function collapses. It cannot exist in two states, beacuse the cat itself is observing which of the two events occur. (As a more simple example, you'll stop hearing it meow, or you'll start smelling its rotting flesh) Also the box isnt an isolated universe, it's connected with everything outside no matter what you do, but thats the same mistake of theoretical fallacy that the thermodynamics conservation of energy makes, imagining that the universe is an isolated CLOSED system, when all observations point to the contrary (is there ANYTHING more OPEN than the universe? lol). I'm not saying equal and opposite reactions isnt true, im just saying we cannot say for certain that mass / energy cant be created nor destroyed in the universe, before we know if the universe IS a closed or open system. Especially when everything points to it being OPEN (even if you take the big bang theory as the universe as a "bubble" of spacetime, you still have theories of membranes interacting or wormholes forming between universes, ANY of those are breaking the "closed system" that thermodynamics assumes as fact). Sorry lol i went on a tangent there..

Blessed to have this opportunity 🙏

I like the question about running out of branches. I would like to speculate that as times passes, and the total amount of possible states increases, detail gets discarded because total information is finite. That's the materialist view of the entire universe. I even think most of the confusion comes from the fact that looking from our personal perspective (we are conscious parts of of this quanta), we also feel that information is finite but this time the total amount of possible states keeps decreasing while detail gets filled in. In other words our mind seems to merge repeatedly towards a more and more detailed picture, contrary to the universe which keeps branching and discarding. Then from a human, collective perspective, you hit a nice middle between the two. There seems to be a stable, renewing flow of possibilities if we don't fill our consciences with useless information.

I like quantum field theory. i can appreciate and understand quantum field theory as a basis for reality. what I can't wrap my head around is how shrodinger/Everett fits into the quantum field theory. I guess they are dependent on other dimensions/many worlds, etc... but I can't understand how many worlds can be a basis for reality. I think we are missing something.

if we where in a simulation it would make sense to save processing power that each object inside the simulation would sit idle unprocessed until an interaction happened and forced the algorithm to calculate the state of the object.

I enjoy listening to Chef John and this guy

I LOVE Quantum Mechanics. Solving the Quantum Theory is a joint effort. Scientists then have entangled work to do!

*_...but, everything, is measuring everything else,-so observation must be a collective, operation... even when you're not looking for yourself right-then... try catnip in your box so it's either going nuts or it's not, which is very subjective to your point-of-observation of cats..._*

happy to see that Ferris Bueller turned out OK

Raises her hand from deep in the Heart of Texas! Love you, Sean.

I had to add an additional thought about Carroll's lucid explanations. As Carroll readily states, his story about QM (a version of Everett's "many worlds" or multiverse) is not shared by the majority of physicists. What is so refreshing is that you can consider the different POVs and draw your own conclusions about the nature of reality. No fake facts here, just insightful discussion. How refreshing.

Promoting an iPhone app at Talks at Google. Ballsy.

I hope there is a universe where i understand quantum mechanics...

A great talk and much more accessible than one would think when approaching such heady topics. Regarding the many-worlds interpretation, I do believe it to be yet another way to hide the fact that there are things we just don't know. Effectively, we are saying that we don't know what the state of the universe will be at time T+1. But why don't we? If each state is a function of the previous state, then the universe is deterministic. If our calculations do not correctly predict the next state, then it must be because the calculations are incorrect. Or more likely, lacking the vast number of variables that we would need to observe from the previous state. The issue is that we don't know the entire state of the universe at any moment and so therefore cannot predict the next. We introduce probability to add the fuzz factor that gets us to something can almost approximate the chaos quantum mechanics.

Spot on, thank you everybody, Doug:).

Huh. Gravity brings things together but may drive expansion. A quantum theory almost seems like it would be recursive / fractal. Like.. if you're far away then its uncertain if you're affecting anything and over time you become less and less relevant as the cumulative irrelevance builds up. But if you are close, you ARE relevant and it cumulatively builds up.

I feel like he's the narrator for a show *The Quantum Wonder Years*

Thank you so much for getting into what is measurement.

That cat being awake or asleep model does not work for one reason: A cat has such a high probability of being asleep regardless of the mechanism being triggered, the whole model breaks down...

A wise man once said "Take a trip to another dimension. Pay close attention"

All in all, enjoy life as it is. You'll never know what will happen in the future as you are never going to know which path split of life you'll take. Just embrace yourself as the quantum observer of the specific quantum state where your life is pathing on, and let go regretting deeply on past mistakes because you're just experiencing one of the multiple quantum states of your life.

Interesting talk. The many worlds theory makes sense and does seem to reconcile some quantum mechanical theorem. I have a friend who once said that maybe that's what happens when we dream. The electrons from the electrical impulses in our brains jump to other branches of existence. That would mean we would not be be the same person between conscious states.

#WaveParticleDuality #TheoryOfEverything What if strings aren’t vibrating string loops, but rather particle orbit trace patterns? The natural first (Occam’s) assumption to explain how or why a particle like a photon (or electron, etc) might behave as an uncertain location particle while also like a polarizable axial or helical wave ''packet'', given that everything in the universe from electrons to solar systems are in orbit with something else pulling them into polarizable axial or helical apparent waves depending on the orientation of their orbits as they travel thru space, and given that we know we’re in a sea of undetectable dark matter but don’t know where it’s disbursed, is that they’re in orbit with an undetectable dark matter particle pulling them into polarizable axial or helical apparent waves as they travel where the speed of their orbit determines the wavelength and the diameter is the amplitude which would explain the double slit, uncertainty, etc. No?

No 'Imaginary' or 'Theoretical' cats were quantumly harmed or killed in the making of this video.

This video was fascinating! I really like this guy!

Brilliant brilliant brilliant. So well done. Thank you.

I think Sean Carroll is hands down the *best* speaker on these very interesting and incredibly difficult subjects of modern physics. Some of his presentations that I've seen were just so insightful, and offered such clarity of thought and explanation. All delivered with wit and warmth. Thank you to Sean, and Google for posting this talk.

I just figured out that the cat in the box is an observer and measures itself as awake of asleep.

Carroll uses the Everett interpretation of QP or "many worlds" to explain the Schrodingers Cat "thought experiment." Presumably this also applies to the famous "double slit experiment," where final results differ, depending on whether the waves/particles passing through the slits are "observed" or not. It would seem that the "superposition of the entire system," where an observer is included in one system and no observer in another, determines if particle points appear on the wall behind the slits or if wave interference pattern dispersions are seen.

he talks about vibrations and i recall Brian Wilson's Good Vibrations, the lyrics, centered around a love song context, are very relevant to this discussion.....

Good talk, he explains it well.

Nice to listen to Steve Buscemi talk about Quantum mechanics.

Thanks for this best lecture

What 3Blue1Brown is for mathematics, Sean Carroll is for physics: the very best teacher in their field.

What's the difference between Many Worlds and one world, where the others aren't actually "there". And since we only experience one...

a little like Gary Shandling !!

Having studied pure mathematics I have a firm belief that Nature is beautiful. Dr. Carroll's approach of showing how gravity could emerge from many worlds quantum mechanics is where I place my bet.

Sean thank you so mutch to talk positive about my theory. IT make heat to my hart serious. Sincères amitiés sean... sincères amitiés Philippe Martin quantum Physics 😎

If Sean is correct about entanglement, I guess everything in the universe is coupled regardless of spacetime. The obvious question then is why the universe exists at all.

His hair is starting to resemble Feynman's.

I see all things changing so fast, that all is new with the passing of every bit of time.

Let's not forget that Feynman didn't add 'yet' to "...nobody understands quantum mechanics" because he thought there might be other possibilities he couldn't think of. So I think it's imperative that his words don't discourage anyone from the idea of understanding things. Richard Feynman was always a great advocate and firm believer in exploring the unknown and questioning, restructuring the knowledge that we currently possess. Sean Carroll and him are very much on the same platform but divergent either in definitions or in the proportion of changes to be introduced to the systems of thought they use.

If you want someone to read a difficult book you like, say “I always get something new out of it” instead of “I’ve been working on it for years and still haven’t fully grasped it”. Quantum physicists are being self aggrandizing by stressing the difficulty

Could dark matter actually be the effect of the many worlds on our experienced version?