First episode I've heard, just came over from your interview with Joe Rogan that came out today. When I heard you tell Joe about spacetime/gravity emerging from quantum mechanics, my heart jumped! I went to a physics colloquium at UCSB (either 2017 or 2018 in Webb Hall across from Broida) where you were giving a talk on spacetime and gravity potentially being emergent properties of a finite dimensional Hilbert Space. Had a great time at that talk; I'll have to look for my notes on it to re-live it somewhat! Wish I had your (to be written) entanglement-centric textbook over Griffitfths when I took QM! Just want to say thank you for being such a wonderful communicator of science, and champion of understanding the reality of quantum mechanics, rather than simply the most complex systems we can successfully predict or conceive. Keep it up!
Just would like to mention honestly and without flattery, that Sean Carroll knows how to elaborate things very well and with simple voice tonality, which reflexes non-arrogance tick that makes it for the audience a pleasant thing to listen. Thanks a lot for all the effort sharing knowledge in such a way.
I recently did some exercises programming a quantum computer. I was surprised how much this could teach me about quantum theory in general. For quantum computing you don't even need to understand physics, if you accept some unitary state transition matrices. And then it's entanglement over and over again that lets you achieve some computational task. I recommend this experience to all physics students.
I've read and listened to a great deal concerning quantum mechanics and gravity, and I feel sure that this podcast contains more, way more, interconnected ideas than anything I have encountered before. I'll be chewing on this for some time, I think, which of course is a compliment.
I've done graduate research in the area and am familiar with Ted Jacobsen's work (and Verlinde and Padmanabhan and others) and just wanted to echo this sentiment. I think having the verbal descriptions Sean provides as conceptual scaffolding REALLY helps put those ideas into a tapestry where those connections are made. He has long been my personal favorite public speaker.
Hi Sean, I had the pleasure of meeting you this morning at the Milwaukee airport, right before our mutual (cancelled) flight. Hope you made it back home without too much trouble! Thanks for doing this new podcast. I'm subscribed. Looking forward to more of them. Take care.
I like this podcast a lot : Either I try to follow your university lectures with most of the stuff outside my math capabilities, or your open lectures which are generalized to to a point where they leave too many questions. In this video however, you explain everything and remember the details and footnotes to build up to your arguments, which makes this much easier to follow. Especially your insights of how to visualise the Quantum world an large scale is an eye opener.
Excellent explanation of QM and the way you link concepts like entanglement, emergence, decoherence, locality and many others. Hope you soon edit and publish the QM book for undergraduates you announce. Tomorrow "Something Deeply Hidden" arrives and I am lovely expecting it. I like the way you refer to the cat as awaken or slept, for those who love cats it is very gentle and respectful to these cute creatures.
In my 7 years of doing physics I’ve never heard anyone describe fields in this way. Thanks for teaching me that! I really enjoy your podcast and all of your books!
Extremely clear and helpful summary - thank you! I have been tasting the individual ingredients listed in a recipe (my past education in QM and physics) for a delicious horizon shaped pizza and this podcast has allowed my mind to taste the finished pie.
An amazing episode from a fantastic podcast. Been looking forward to this new book. Grateful for Sean Carroll -- gifted communicator par excellence with a nice humble style
Well, that's a challenging 110 minutes! I think I was somewhat in touch for the first thirty minutes but the last hour was a struggle to even crudely comprehend aside from a few flashes. Not that I am complaining, I love these podcasts and it's great to be challenged and have (far) more depth than I can manage. Brilliantly done, thanks so much for the series. More Susskind, and more QM, please!
i like you sean, and think your cool AF. i build houses with my hands, but i dream of space all day long. you bring it to a point where i can fathom some seriously complicated shit. thanks from the world for your gift!
another big fan here filled with awe for your easy style, mr carroll. i do enjoy that you do not say a word ABOUT consciousness anymore. but you put my mind in a very agreable state with everything else. thank you.
It's refreshing when someone with such a deep, advanced knowledge of cosmology can break very deep topics down into bite sized, manageable pieces for an average person
Thank you Sean for a great capstone summary. I'm a long-time fan of your work. You have a gift for clarity of thought and expression! Would love to hear you have Tim Maudlin on the podcast someday.
I want swim pants that says "it's *this* cold", and then if you zoom really (really) in, there's a penis drawing on the scale of the planck lenght. I need to first be able to draw objects that small, of course, but that's what the kickstarter is for.
Thank you for taking the time to share your knowledge to a degree of experience that is not “spelled out” through “simple education”, however, you, explained, through experience from education from your individual experiences. I really appreciate your description based on “multiple opinions” to express “your own.” I agree with your message within my heart. Thank you for your time to share your knowledge.
Sean Carr-OLL?...I just love that 'question intonation' thing he does in his speech at the end of each phra-SE and sente-NCE? ,he utters?: He just sounds so open, friendly, open-minded and questioning: He's such an incredible, logical, reasoning, intuitive genius.
Wow I find this so fascinating, I believe when you were on the Event horizon podcast you mentioned the universe itself being in superposition. That just blew my mind!
I salute Your intention of writing a new textbook on QM for undergraduate, as I really agree to Your view that the traditional presentation of QM is a monstrous disservice to students approaching QM in 2020, for the very reason that You expose.
I’m a fan, Dr. Carroll I’m writing from the Netherlands and I hope you would address this explanation I have of a superposition: When we toss a coin in the air, the coin is in a superposition until it hits the floor. While it is in the air tossing, it is both H and T. With a probability it is H and with another probability it is T. And we are in the Classic world and not in a quantum world. Hitting the floor is equivalent to “being observed”. And all our experiences in life is like that. I do hope you will somehow read this comment /question, on this January 9, 2021 day that I’m writing this in Alkmaar, a pretty Dutch town in the Netherlands!
34:00 - 34:11 That is an assumption. Throughout this discussion, you've sneakily included the (contentious) premise that Psi/the Schrodinger equation/ the wavefunction is ontological.
Is there a way to give multiple likes to a video? This is the best episode yet where Sean connects every quantum and cosmological theory you've ever heard onto a map with Many Worlds at the center.
Thanks, Sean. It was really great to combine mentally together the Schrodinger's cat with a black hole. nice job! It looks, that the cat is living within ER bridge, watching the Universe from there, while having EPR ties on the opposite side of the bridge.;)
I believe atoms are tiny solar systems and that electrons are tiny planets. The tiny planet is a particle and the tiny gravity of the electrons orbit is the wave function.
Amazing!!! thank you so much. I am just a normal person following science and this is one of the gold nuggets i found in a long time. Also mindblowing was Burkhard Heims theory. I think he goes along with this view on quantum mechanics.
The reason the 23:12 narrative of Schrödinger's cat t.ly/rFDi is popular and memorable is that it is macabre. Macabre concepts stand out in the memory because we have evolved to pay special attention to them. (The Major Memory System takes advantage of this.) That's why the cat doesn't only sleep.
Now, this should be interesting. Sean always has a good show. I wonder, however, how could there be "Gravy" in Quantum Mechanics. Let me get my glasses here...
@seancarroll at 40:34 you talked about the fact that we never see schroedinger's cat in superposition: - cat is either awake or asleep - an observer is either seeing a cat either awake or asleep After the observer, cat and the photons in between are entangled, is it correct to understand that **the universe is in superposition again**: a superposition of "cat is asleep and an observer sees a cat asleep", and "cat is awake and an observer sees a cat awake"?
That description of locality emerging from entanglement is mindblowing, does that in principle reconcile epr with locality? The second particle is "local", after all? This channel is fantastic, right in the middle between basic videos and what you get when studing the full physics...
Thank you Sean!!! One comment though, you end a lot of statements with “OK??”. But often those statements are of such magnitude as “space is the property with respect to which interactions are local. OK?” If you are asking, which the intonation would suggest you are, the answer is No! They don’t just absorb like that. Again thanks for this one, I’m going to have to listen to it many more times, but for future reference when you ask “OK??”, just know the answer is “NO!!! Not yet” lol
I wonder who are the people who 'dislike' this kind of stuff. Sean may be right or wrong, but there is nothing wrong with having a coherent point of view,
Gravity waves are infinitely minute, so why can't we ascertain that the energy they fluctuate at the quantum level is what feeds the vibrations of the constituents of atoms? They travel through spacetime from every direction of the universe, so they must be transmitting energy. Energy at the tiniest levels we see actions of quarks etc. The electron may stay in oscillation around the atom being fed by gravitational waves. Gr8! Peace ☮💜Love
"Inflation" would be a very natural expectation in a decoherence based gravity, or emergent geometrodynamical extension based on interaction-locality. Indeed, probably the emergence of extension would be more effective when decoherence is more effective, i.e. when more systems have a chance to interact with each other, i.e. when they are all close... i.e. when it's big bang time. :P
So, if I've got this right, you're starting with a finite set representing the universe's phase space and defining a Topology with the desired properties. To get the holographic properties I think it is compact but not connected. To be Hilbert it necessarily has a metric. This allows us to define a lattice over the compact subsets. So now we get to define length, area, volume, angles, etc. Now we can define entropy as being proportional the surface area compact subset. At this point we can work out spacetime and gravity. IS THIS, MORE OR LESS, THE BASIC PROGRAM?
37:21 well, can't we interpret that we get entangled with the cat either sleeping or awake instead of saying that the wave function collapsed, but not interpret that all the other branches exist, specially if there is no way for these branching universes interact with each other, they might as well not exist 🤔
I think that one of the first things that might be good to clarify to the general public is splits occur on quantum states e.g. spin of an electron (up / down), and probably not arbitrary life / historical choices for macro systems. I think chaos and attractors could play more important roles on how these branches evolve.
Thank you for these and all the other podcasts, specially about quantum mechanics. I look forward to read your new book, and I hope that it will be translate in Portuguese (quantum mechanics is already hard enough...).
Mr. Morris and myself applaud your respect for the life of cats. Edit my cat is Morris the cat 🐈 😻 and over the years you have made so much information available to people who can't afford college like myself and while care giving for my mama I can mindscape for a little when I need a little escape 👏
I wish I understood what sense to attach to the concept of "part" as in when, in the description of Schrodinger's cat, it is asserted that a "part of the wavefunction says the atom has emitted a particle and part of it says the atom has not emitted such a particle". What is meant by "part" here? Are we to take it a spatial reference, as in this "part" of the room? Or are we to understand "part" in some other sense?
That was a treat! Question: Is entanglement really the only phenomenon in the universe? A wave function is linear and just spreads out or passes through itself. When you have an event like a particle interaction shown as a Feynman diagram with thee lines meeting at a point, a very non-linear thing happens. Some particles come in, and very different particles go out. Are all such 3-way interactions different types of entanglement? I understand entanglement as the variables of the universe changing place. On one side of the diagram the wave function of the universe describes two electrons and on the other side it describes a photon, so the information is conserved but somehow rearranged. Is that re-arrangement of information the same thing as entanglement?
Let me put it another way: First the universe has a wave function for the EM field that we say describes two photons. Then they interact and the wave function in another field describes an electron. Later we do something and entangle that electron with another one so that we know some combined property of the pair. And finally we "measure" the position of one electron by entangling it with some apparatus and that "collapses" the related property of both of them. In my mind there seems to be something common in all these steps, and it looks like the number of degrees of freedom involved is conserved but they change place to describe different things. I wonder if there's one generic "event" in the universe which means "the degrees of freedom are rearranged". Maybe Sean can enlighten us in his forthcoming textbook.
@@robertbrandywine I'm not a physicist. My understanding is there's one wave function per quantum field of the standard model, so that makes 17 of them in the Universe? For example there's a wave function for photons. All the photons are ripples in that wave functions. There's another one for electrons. All the electrons anywhere are ripples in that wave function.
Just sat throigh your explanation of decoherence 27:00 re a dust grain and three words fom a well-known Mell Brooks movie, Blazing Saddles come to mind: Authentic Frontier Gibberish
Hi Sean, I doubt you'll see this and respond, but I have listened to all of your lectures and podcasts on QM and there is something I still don't understand about many-worlds. It essentially boils down to: why do we ever observe something "particle like"? It would seem as though if everything (including ourselves) is wave-like then we would simply observe things to be wavelike, even if we are beginning to be smeared across possibility space and are only observing parts of the wave. Where do these point-like events suddenly come from? I have a feeling it has to do with that part about chopping up the wavefunction into localized pieces of space in a unique way, but that's going way over my head.
But there is high dimensional continuum of positions of the cat, not just asleep and awake. So are there an infinite number of observers outside the box even before it's opened? How far away can the observed by to avoid this locality effect?
13:43 That is a convenient way of putting it. I mean, I can be open to Carroll's ideas, but to presume that "many worlds" is pure because of its adherence to strict formal mathematics is a play on words. Purity, in the sense Carroll uses it here, is mathematical. But, as we know, mathematics is one of the most (if not the most) abstract of fields. This means it's closer to mental abstractions than to empirical experiments. If you are talking physics, one would think pure formal mathematics is exactly what muddies its waters and not what purifies it. I'm not saying Carroll's many world's interpretation (call it formulation, it is still an interpretation... no way around it) is wrong or ill proposed, but the pretension of purity is very unnecessary and misleading. If the idea works, is not because it is pure. C'mon, Sean, be humble. You imply those who don't agree with you "don't like" the many worlds, and that to agree with you is not about "liking" the theory more but about rigor, when you clearly "like" the aesthetics of your supposedly pure mathematics. All this valuing and dissing theories on no factual grounds is absolutely unnecessary for your theory to stand, if it does. 16:56 Absolutely agree. 28:01 Well, decoherence or collapse, the problem still remains in "many worlds", there is an unexplained process marco variables emerging and (in addition) branching the whole universe with it. In Carroll's words, there's still "lying". Not that it's wrong, again, but it should be emphasized: IT IS A BET, A HYPOTHESIS. No real experiment behind, just supposed "purity" of mathematical formalism. 36:45 C'mon, this is a silly dichotomy to still be saying is a thing. No one serious still interprets "observing" as specifically related to human eyes. 45:05 Excellent! Now we're getting somewhere! 55:14 Agreed on both counts. We don't know. And I do follow Carroll in that fork in the road and make the same assumption. 57:22 Well, it would be worth mentioning Carlo Rovelli, who gives a serious alternative to Carroll's... the be fair, he has written his name in some presentations. 1:43:10 Again, that is a somewhat misleading way of putting it, in which it might seem that the only or best alternative to Copenhagen interpretation is "many worlds", but these are not the only two alternatives. There are others that meet the "serious" quality Sean himself says we should expect from physicists. But as Sean says, again, "MAYBE". Overall, a great podcast! I'll be checking out that book tomorrow!
im also not sure how the MWI deals with the quantum eraser experiments, supposedly you measure some observable and then destroy that information therefore preserving the wavefunction. does that mean in MWI that it de-branched after the first measurement?
Are the "worlds" in the many-worlds interpretation mathematically just a kind of vector subspaces onto which the vectors (the wave functions) can be projected to? And then we need to figure out how transformations of the wave functions translate to gravity acting in those vector subspaces?
So important information, my naturalistic and physicalistic worldview was in a headache because of the clasical meachanic and wave function understanding, if the world in fundamental level is wave function so why the world is clasical? Sean showed me this important podcast and begning to understand this isue.
Is it necessary to have the different outcomes be branches. I can easily envision the parallel outcomes having parallel backstory as well. Entirely identical until the day of the fateful cat-napping.
I have no idea if I only just noticed or if Sean got that "Ok...?" from David Albert :D On a side note - if you are reading this Sean, you need another appearance on World Science Festival or even better at The Royal Institution. You are very good talker!
17:30 Kinda like trying to figure out how to fix a micro-chip with a spanner. Uneducated what if, "what if anti-De-sitter space is what't on the "inside" of the black hole?
Entropic gravity and decoherence gravity... that they are linked is a very natural expectation considering that both entropy and decoherence are aspects of entanglement. Then, we also know that entanglement is "informed" about curvature: for quantum correlations to be encoded over a curved space-time, we need parallel transportation of the observables over the trajectories of entangled particles just to make sense of which are the observables respect to which results correlates. That is to say that entanglement implicitly, by encoding correlations, picks up information about the curvature along the trajectories. What if there is no more information about curvature than the one entanglement picks up? It would mean that entanglement encodes curvature, at least implicitly.
I also found that charge comes from the particle while gravity comes from the wave part of it . Another words the momentum of the electron = it's gravitational attraction x it's freguency
I have a question about wave particle duality and the wavefunction. My question is what if an electron is just a particle and time is actually a wave. What if the interference pattern from the double slit experiment is because the electron is riding on a time wave, similar to pilot wave theory. How does this affect The Schrödinger equation and our fundamental understanding of quantum mechanics?
Emergent space and locality of interaction, I agree. Note that what is emergent of space (Sean means space-time of course) is its extension, i.e. its metric. We have the parametric representation of space already encoded in the interactions, i.e. in the particle-fields of QFT. These are the dynamical-kinematic symmetries of space-time. But this is only parametric and special relativity, and we want metric and general relativity (=geometrodynamics), i.e. we want extension. (We want it because we see it, we know that it is part of the empirical experience, thus our physical theory must yield it). In this sense, and in view of the task at hand, QFT might be regarded as a tangent space, in the very same sense that SR is a tangent space, a space of generators, to general relativity. We need to go from the parametric to the metric, from the tangent space to the extended space. Extension is exactly the distinction of locality, what is here and what is not, i.e. exactly what interacts with this and what not. Starting from interactions, and defining locality from the starting point of the parametric (tangent space) might resolve the conundrum between (extended!)space and locality because it doesn't need to assume an extended space, it can then Yield extension as emergent, by decoherence, just as it yields the emergence of locality out of the parametric-tangent space. Indeed the notions of locality and extension are made dual. It is the interpretation of QM itself that suggests that decoherence could yield the "unfolding" of space-time, the emergence of locality-extension, in the very same sense we are discussing it here. Incidentally, if QFT was a tangent space in a profounder sense than what assumed above, it would make sense that any field would fail to be "gravity" at the fundamental level: tangent spaces can't properly deal with circuitations, extensions do. See the twin problem in SR, SR can't solve it because it does not know what a change of speed is, even when it does know what the correct computation would be... if it only could recognize the change of speed! A tangent space only deals with pass-bys, not returns. This suggests that, perhaps, we might want to pause, make a step back, and reconsider our computations in QFT figuring out if there is a distinction to make between a parametric (tangent space) computation and an extended (relating to the extension space) computation. Mmmm, we have loops in there and they are where we need renormalization... has it anything to do with this?!? Don't know, let it hang here...
Can someone explain why the entanglement is set to inversely proportional to distance (instead of inversely proportional to the square) when defining a quantum system such that you can derive 3D space?
Is splitting worlds entropy in some way? Is time just splitting worlds? I'm tripping ballz. Are we just snapshots with a brain at each snapshot telling us we are a person with continuity?
First episode I've heard, just came over from your interview with Joe Rogan that came out today. When I heard you tell Joe about spacetime/gravity emerging from quantum mechanics, my heart jumped! I went to a physics colloquium at UCSB (either 2017 or 2018 in Webb Hall across from Broida) where you were giving a talk on spacetime and gravity potentially being emergent properties of a finite dimensional Hilbert Space. Had a great time at that talk; I'll have to look for my notes on it to re-live it somewhat! Wish I had your (to be written) entanglement-centric textbook over Griffitfths when I took QM!
Just want to say thank you for being such a wonderful communicator of science, and champion of understanding the reality of quantum mechanics, rather than simply the most complex systems we can successfully predict or conceive. Keep it up!
joe rogan! really?
Just would like to mention honestly and without flattery, that Sean Carroll knows how to elaborate things very well and with simple voice tonality, which reflexes non-arrogance tick that makes it for the audience a pleasant thing to listen. Thanks a lot for all the effort sharing knowledge in such a way.
Just want to say thanks for doing these podcasts. I have recently found your channel and I am greatly enjoying them. You are an excellent host!
You should check out his series on dark matter with great courses plus. Phenomenal teacher, this dude. (aka the teaching company - TTC)
Turned it off after the first 2 ads in 8 mins.
I'm glad the universe split for this version of me in such a way I found Sean Carroll and these podcasts.
Of course it did!
Agreed! But it looks like we've taken a wrong turn somewhere, this 2020 seems a few standard deviations from the mean.
A lot of content in this podcast. I've listened to it a few times and will do again a few more 🙃
very good humor but ya i guess
You’re probably listening to Sean in most of those worlds
I recently did some exercises programming a quantum computer. I was surprised how much this could teach me about quantum theory in general.
For quantum computing you don't even need to understand physics, if you accept some unitary state transition matrices. And then it's entanglement over and over again that lets you achieve some computational task.
I recommend this experience to all physics students.
I've read and listened to a great deal concerning quantum mechanics and gravity, and I feel sure that this podcast contains more, way more, interconnected ideas than anything I have encountered before. I'll be chewing on this for some time, I think, which of course is a compliment.
I've done graduate research in the area and am familiar with Ted Jacobsen's work (and Verlinde and Padmanabhan and others) and just wanted to echo this sentiment. I think having the verbal descriptions Sean provides as conceptual scaffolding REALLY helps put those ideas into a tapestry where those connections are made. He has long been my personal favorite public speaker.
Hi Sean, I had the pleasure of meeting you this morning at the Milwaukee airport, right before our mutual (cancelled) flight. Hope you made it back home without too much trouble! Thanks for doing this new podcast. I'm subscribed. Looking forward to more of them. Take care.
I like this podcast a lot : Either I try to follow your university lectures with most of the stuff outside my math capabilities, or your open lectures which are generalized to to a point where they leave too many questions. In this video however, you explain everything and remember the details and footnotes to build up to your arguments, which makes this much easier to follow. Especially your insights of how to visualise the Quantum world an large scale is an eye opener.
Excellent explanation of QM and the way you link concepts like entanglement, emergence, decoherence, locality and many others. Hope you soon edit and publish the QM book for undergraduates you announce. Tomorrow "Something Deeply Hidden" arrives and I am lovely expecting it. I like the way you refer to the cat as awaken or slept, for those who love cats it is very gentle and respectful to these cute creatures.
Look SS, about your cat, I'm afraid I have good news and bad news.
4 lmao...that's really funny...probably overlooked
In my 7 years of doing physics I’ve never heard anyone describe fields in this way. Thanks for teaching me that! I really enjoy your podcast and all of your books!
Extremely clear and helpful summary - thank you! I have been tasting the individual ingredients listed in a recipe (my past education in QM and physics) for a delicious horizon shaped pizza and this podcast has allowed my mind to taste the finished pie.
…bean tasting ;)
This is by far my favorite episode so far!! Thank you Sean.
Sean, this may be your finest hour.
These podcasts are awesome ….specially the ones on physics. Looking forward to listening to more. THANKS!
this is one of the few best thing that happened to the internet. I'm a huge fan of you sean ✌
I really like the intellectual honesty in his approach to quantum mechanics and the clarity of his descriptions.
An amazing episode from a fantastic podcast. Been looking forward to this new book. Grateful for Sean Carroll -- gifted communicator par excellence with a nice humble style
Your podcasts are wonderful, Sean and you are the most articulate science educator I've had the pleasure to listen to.
Well, that's a challenging 110 minutes! I think I was somewhat in touch for the first thirty minutes but the last hour was a struggle to even crudely comprehend aside from a few flashes. Not that I am complaining, I love these podcasts and it's great to be challenged and have (far) more depth than I can manage.
Brilliantly done, thanks so much for the series. More Susskind, and more QM, please!
Yeah, my head hurts slightly after listening to that -- and I'm not kidding.
Really enjoying these solo episodes, Carroll is a legend.
i like you sean, and think your cool AF. i build houses with my hands, but i dream of space all day long. you bring it to a point where i can fathom some seriously complicated shit. thanks from the world for your gift!
another big fan here filled with awe for your easy style, mr carroll.
i do enjoy that you do not say a word ABOUT consciousness anymore. but you put my mind in a very agreable state with everything else. thank you.
It's refreshing when someone with such a deep, advanced knowledge of cosmology can break very deep topics down into bite sized, manageable pieces for an average person
Thank you Sean for a great capstone summary. I'm a long-time fan of your work. You have a gift for clarity of thought and expression! Would love to hear you have Tim Maudlin on the podcast someday.
One of my favorites eps, thanks much!
Thanks Dr Carroll. I always enjoy your podcast. Very enlightning.
Khairul from Malaysia
I want a Mindscape T-shirt that says "As quantum as you can get"
Me, too!
Oh boy!
@@skatekraft I want one too that says - Mindscape Localize your gravity in spacetime
I want swim pants that says "it's *this* cold", and then if you zoom really (really) in, there's a penis drawing on the scale of the planck lenght. I need to first be able to draw objects that small, of course, but that's what the kickstarter is for.
But, it will say that only when someone is reading it.
Thank you for taking the time to share your knowledge to a degree of experience that is not “spelled out” through “simple education”, however, you, explained, through experience from education from your individual experiences. I really appreciate your description based on “multiple opinions” to express “your own.” I agree with your message within my heart. Thank you for your time to share your knowledge.
Did i just find a Sean Carroll's channel?! Thank you, TH-cam!
Reason why I get all your audio books, stuff like this as well. Thank u
Sean Carr-OLL?...I just love that 'question intonation' thing he does in his speech at the end of each phra-SE and sente-NCE? ,he utters?: He just sounds so open, friendly, open-minded and questioning: He's such an incredible, logical, reasoning, intuitive genius.
Basically a free lecture on the latest research! Thanks!!
Wow I find this so fascinating, I believe when you were on the Event horizon podcast you mentioned the universe itself being in superposition. That just blew my mind!
I salute Your intention of writing a new textbook on QM for undergraduate, as I really agree to Your view that the traditional presentation of QM is a monstrous disservice to students approaching QM in 2020, for the very reason that You expose.
I’m a fan, Dr. Carroll
I’m writing from the Netherlands and I hope you would address this explanation I have of a superposition:
When we toss a coin in the air, the coin is in a superposition until it hits the floor.
While it is in the air tossing, it is both H and T. With a probability it is H and with another probability it is T.
And we are in the Classic world and not in a quantum world.
Hitting the floor is equivalent to “being observed”. And all our experiences in life is like that.
I do hope you will somehow read this comment /question, on this January 9, 2021 day that I’m writing this in Alkmaar, a pretty Dutch town in the Netherlands!
This was as deep as a black hole. Intense! So amazing.
You are an EXCELLENT professor Sean. Thank you Very Much for your devotion.
Your explanations are way better than any documentary I've seen on TV(like Discovery or National Geographic)
Thank You!
34:00 - 34:11 That is an assumption. Throughout this discussion, you've sneakily included the (contentious) premise that Psi/the Schrodinger equation/ the wavefunction is ontological.
I don't think he has done that sneakily, he's pretty explicit about being an Everettian where the wave function is the truest fact about reality.
He sneakily says that is his viewpoint in the beginning.
Is there a way to give multiple likes to a video? This is the best episode yet where Sean connects every quantum and cosmological theory you've ever heard onto a map with Many Worlds at the center.
Yes, shift throughout the multiverse wave function and like the video in the alternate realities as many times as you like!
Thanks Sean. I don't understand a word your saying but you state it with CONFIDENCE!
Thanks, Sean. It was really great to combine mentally together the Schrodinger's cat with a black hole. nice job!
It looks, that the cat is living within ER bridge, watching the Universe from there, while having EPR ties on the opposite side of the bridge.;)
That Jacobson insight/speculation is sweet.
I believe atoms are tiny solar systems and that electrons are tiny planets. The tiny planet is a particle and the tiny gravity of the electrons orbit is the wave function.
Amazing!!! thank you so much. I am just a normal person following science and this is one of the gold nuggets i found in a long time.
Also mindblowing was Burkhard Heims theory. I think he goes along with this view on quantum mechanics.
I wasn’t aware that Sean had a podcast. I love it
i bought the book and read it and then listened to it, now his lectures sink in more to me :)
YES!!! I have been looking forward to this talk on gravity and the new book coming out.
The reason the 23:12 narrative of Schrödinger's cat t.ly/rFDi is popular and memorable is that it is macabre. Macabre concepts stand out in the memory because we have evolved to pay special attention to them. (The Major Memory System takes advantage of this.) That's why the cat doesn't only sleep.
When you get the blanket thing you can relax... because everything you could ever want or be, you already have and are.
Thank you very much for doing these podcasts
Blows my mind every time. Great episode!
Well, I know what I will use my audible credit for!
Now, this should be interesting. Sean always has a good show. I wonder, however, how could there be "Gravy" in Quantum Mechanics. Let me get my glasses here...
Love the show Sean!
"Theoretical physics is all about trying it out". Professor Sean Carroll 2019.
@seancarroll at 40:34 you talked about the fact that we never see schroedinger's cat in superposition:
- cat is either awake or asleep
- an observer is either seeing a cat either awake or asleep
After the observer, cat and the photons in between are entangled, is it correct to understand that **the universe is in superposition again**: a superposition of "cat is asleep and an observer sees a cat asleep", and "cat is awake and an observer sees a cat awake"?
Wow is it weird i have this in my head word for word very easily. Trip out. On quantum mechanics.
Giving interaction in comments to make analytics better because you deserve more exposure.
answering to you for the same reasons :) I can't imagine how this has 2k views...
Just when I think I am out, many worlds pulls me back in...
but also doesn’t at the same time in another universe
Hi Sean, Quantum all the way !! keep it Up
That description of locality emerging from entanglement is mindblowing, does that in principle reconcile epr with locality? The second particle is "local", after all?
This channel is fantastic, right in the middle between basic videos and what you get when studing the full physics...
Where Dr. Carroll makes me a believer in many-worlds.
Thank you Sean!!! One comment though, you end a lot of statements with “OK??”. But often those statements are of such magnitude as “space is the property with respect to which interactions are local. OK?” If you are asking, which the intonation would suggest you are, the answer is No! They don’t just absorb like that. Again thanks for this one, I’m going to have to listen to it many more times, but for future reference when you ask “OK??”, just know the answer is “NO!!! Not yet” lol
I wonder who are the people who 'dislike' this kind of stuff.
Sean may be right or wrong, but there is nothing wrong with having a coherent point of view,
Gravity waves are infinitely minute, so why can't we ascertain that the energy they fluctuate at the quantum level is what feeds the vibrations of the constituents of atoms? They travel through spacetime from every direction of the universe, so they must be transmitting energy. Energy at the tiniest levels we see actions of quarks etc. The electron may stay in oscillation around the atom being fed by gravitational waves. Gr8! Peace ☮💜Love
"Inflation" would be a very natural expectation in a decoherence based gravity, or emergent geometrodynamical extension based on interaction-locality.
Indeed, probably the emergence of extension would be more effective when decoherence is more effective, i.e. when more systems have a chance to interact with each other, i.e. when they are all close... i.e. when it's big bang time. :P
Anyone know the paper he is referencing at 57:58. The Cutler et al paper
As I hear this changes my life
So, if I've got this right, you're starting with a finite set representing the universe's phase space and defining a Topology with the desired properties. To get the holographic properties I think it is compact but not connected. To be Hilbert it necessarily has a metric. This allows us to define a lattice over the compact subsets. So now we get to define length, area, volume, angles, etc. Now we can define entropy as being proportional the surface area compact subset. At this point we can work out spacetime and gravity. IS THIS, MORE OR LESS, THE BASIC PROGRAM?
U rule dude. - Nano Pharr, Texas 2019
Listening to this i feel I'm way over my head. Thankfully i can borrow yours. Thank You! :D
Thanks Sean Carroll for all you do to try to explain science and esspecially QM.
Sean, Brian and Neil are leading the game
IMHO Sean goes much deeper with more clarity that the other two.
Chip Hill lol Brian’s green elegant universe is deep
If this is in Barnes and noble tomorrow, I’m gonna grab it
37:21 well, can't we interpret that we get entangled with the cat either sleeping or awake instead of saying that the wave function collapsed, but not interpret that all the other branches exist, specially if there is no way for these branching universes interact with each other, they might as well not exist 🤔
I think that one of the first things that might be good to clarify to the general public is splits occur on quantum states e.g. spin of an electron (up / down), and probably not arbitrary life / historical choices for macro systems. I think chaos and attractors could play more important roles on how these branches evolve.
Thank you for these and all the other podcasts, specially about quantum mechanics. I look forward to read your new book, and I hope that it will be translate in Portuguese (quantum mechanics is already hard enough...).
Doesn't AI translate reliably these days?
Mr. Morris and myself applaud your respect for the life of cats.
Edit my cat is Morris the cat 🐈 😻 and over the years you have made so much information available to people who can't afford college like myself and while care giving for my mama I can mindscape for a little when I need a little escape 👏
My favourite episode so far.
I'm a many worlds believer now.
Can't wait to buy Something deeply hidden
Love these podcasts!
I wish I understood what sense to attach to the concept of "part" as in when, in the description of Schrodinger's cat, it is asserted that a "part of the wavefunction says the atom has emitted a particle and part of it says the atom has not emitted such a particle". What is meant by "part" here? Are we to take it a spatial reference, as in this "part" of the room? Or are we to understand "part" in some other sense?
May the Force/wave function be with you :)
I would love to take part in an undergraduate course and lecture taught by you
That was a treat! Question: Is entanglement really the only phenomenon in the universe? A wave function is linear and just spreads out or passes through itself. When you have an event like a particle interaction shown as a Feynman diagram with thee lines meeting at a point, a very non-linear thing happens. Some particles come in, and very different particles go out. Are all such 3-way interactions different types of entanglement? I understand entanglement as the variables of the universe changing place. On one side of the diagram the wave function of the universe describes two electrons and on the other side it describes a photon, so the information is conserved but somehow rearranged. Is that re-arrangement of information the same thing as entanglement?
In your example you mention electrons and photons, so their existence is additional to entanglement.
Let me put it another way: First the universe has a wave function for the EM field that we say describes two photons. Then they interact and the wave function in another field describes an electron. Later we do something and entangle that electron with another one so that we know some combined property of the pair. And finally we "measure" the position of one electron by entangling it with some apparatus and that "collapses" the related property of both of them. In my mind there seems to be something common in all these steps, and it looks like the number of degrees of freedom involved is conserved but they change place to describe different things. I wonder if there's one generic "event" in the universe which means "the degrees of freedom are rearranged". Maybe Sean can enlighten us in his forthcoming textbook.
@@PavlosPapageorgiou Maybe you can answer the question I asked above. Is there just one wave function, or one wave function for each particle field?
@@robertbrandywine I'm not a physicist. My understanding is there's one wave function per quantum field of the standard model, so that makes 17 of them in the Universe?
For example there's a wave function for photons. All the photons are ripples in that wave functions. There's another one for electrons. All the electrons anywhere are ripples in that wave function.
Just sat throigh your explanation of decoherence 27:00 re a dust grain and three words fom a well-known Mell Brooks movie, Blazing Saddles come to mind: Authentic Frontier Gibberish
Hi Sean, I doubt you'll see this and respond, but I have listened to all of your lectures and podcasts on QM and there is something I still don't understand about many-worlds. It essentially boils down to: why do we ever observe something "particle like"? It would seem as though if everything (including ourselves) is wave-like then we would simply observe things to be wavelike, even if we are beginning to be smeared across possibility space and are only observing parts of the wave. Where do these point-like events suddenly come from? I have a feeling it has to do with that part about chopping up the wavefunction into localized pieces of space in a unique way, but that's going way over my head.
But there is high dimensional continuum of positions of the cat, not just asleep and awake. So are there an infinite number of observers outside the box even before it's opened? How far away can the observed by to avoid this locality effect?
So excited for the book!!
13:43 That is a convenient way of putting it. I mean, I can be open to Carroll's ideas, but to presume that "many worlds" is pure because of its adherence to strict formal mathematics is a play on words. Purity, in the sense Carroll uses it here, is mathematical. But, as we know, mathematics is one of the most (if not the most) abstract of fields. This means it's closer to mental abstractions than to empirical experiments. If you are talking physics, one would think pure formal mathematics is exactly what muddies its waters and not what purifies it. I'm not saying Carroll's many world's interpretation (call it formulation, it is still an interpretation... no way around it) is wrong or ill proposed, but the pretension of purity is very unnecessary and misleading. If the idea works, is not because it is pure. C'mon, Sean, be humble. You imply those who don't agree with you "don't like" the many worlds, and that to agree with you is not about "liking" the theory more but about rigor, when you clearly "like" the aesthetics of your supposedly pure mathematics. All this valuing and dissing theories on no factual grounds is absolutely unnecessary for your theory to stand, if it does.
16:56 Absolutely agree.
28:01 Well, decoherence or collapse, the problem still remains in "many worlds", there is an unexplained process marco variables emerging and (in addition) branching the whole universe with it. In Carroll's words, there's still "lying". Not that it's wrong, again, but it should be emphasized: IT IS A BET, A HYPOTHESIS. No real experiment behind, just supposed "purity" of mathematical formalism.
36:45 C'mon, this is a silly dichotomy to still be saying is a thing. No one serious still interprets "observing" as specifically related to human eyes.
45:05 Excellent! Now we're getting somewhere!
55:14 Agreed on both counts. We don't know. And I do follow Carroll in that fork in the road and make the same assumption.
57:22 Well, it would be worth mentioning Carlo Rovelli, who gives a serious alternative to Carroll's... the be fair, he has written his name in some presentations.
1:43:10 Again, that is a somewhat misleading way of putting it, in which it might seem that the only or best alternative to Copenhagen interpretation is "many worlds", but these are not the only two alternatives. There are others that meet the "serious" quality Sean himself says we should expect from physicists. But as Sean says, again, "MAYBE".
Overall, a great podcast! I'll be checking out that book tomorrow!
im also not sure how the MWI deals with the quantum eraser experiments, supposedly you measure some observable and then destroy that information therefore preserving the wavefunction. does that mean in MWI that it de-branched after the first measurement?
Physicists have made excellent progress throughout history assuming that the the universe is mathematical at its core, which appears to be the case.
Chip Hill I don’t agree. It’s different to use math to describe reality than to assume it is the base reality. Not the same thing even for physicists.
Are the "worlds" in the many-worlds interpretation mathematically just a kind of vector subspaces onto which the vectors (the wave functions) can be projected to? And then we need to figure out how transformations of the wave functions translate to gravity acting in those vector subspaces?
So important information, my naturalistic and physicalistic worldview was in a headache because of the clasical meachanic and wave function understanding, if the world in fundamental level is wave function so why the world is clasical? Sean showed me this important podcast and begning to understand this isue.
Is it necessary to have the different outcomes be branches. I can easily envision the parallel outcomes having parallel backstory as well. Entirely identical until the day of the fateful cat-napping.
I have no idea if I only just noticed or if Sean got that "Ok...?" from David Albert :D
On a side note - if you are reading this Sean, you need another appearance on World Science Festival or even better at The Royal Institution. You are very good talker!
17:30 Kinda like trying to figure out how to fix a micro-chip with a spanner.
Uneducated what if, "what if anti-De-sitter space is what't on the "inside" of the black hole?
Entropic gravity and decoherence gravity... that they are linked is a very natural expectation considering that both entropy and decoherence are aspects of entanglement.
Then, we also know that entanglement is "informed" about curvature: for quantum correlations to be encoded over a curved space-time, we need parallel transportation of the observables over the trajectories of entangled particles just to make sense of which are the observables respect to which results correlates. That is to say that entanglement implicitly, by encoding correlations, picks up information about the curvature along the trajectories. What if there is no more information about curvature than the one entanglement picks up? It would mean that entanglement encodes curvature, at least implicitly.
I also found that charge comes from the particle while gravity comes from the wave part of it . Another words the momentum of the electron = it's gravitational attraction x it's freguency
Best one yet !
I have a question about wave particle duality and the wavefunction. My question is what if an electron is just a particle and time is actually a wave. What if the interference pattern from the double slit experiment is because the electron is riding on a time wave, similar to pilot wave theory. How does this affect The Schrödinger equation and our fundamental understanding of quantum mechanics?
Emergent space and locality of interaction, I agree. Note that what is emergent of space (Sean means space-time of course) is its extension, i.e. its metric.
We have the parametric representation of space already encoded in the interactions, i.e. in the particle-fields of QFT. These are the dynamical-kinematic symmetries of space-time.
But this is only parametric and special relativity, and we want metric and general relativity (=geometrodynamics), i.e. we want extension. (We want it because we see it, we know that it is part of the empirical experience, thus our physical theory must yield it).
In this sense, and in view of the task at hand, QFT might be regarded as a tangent space, in the very same sense that SR is a tangent space, a space of generators, to general relativity.
We need to go from the parametric to the metric, from the tangent space to the extended space.
Extension is exactly the distinction of locality, what is here and what is not, i.e. exactly what interacts with this and what not.
Starting from interactions, and defining locality from the starting point of the parametric (tangent space) might resolve the conundrum between (extended!)space and locality because it doesn't need to assume an extended space, it can then Yield extension as emergent, by decoherence, just as it yields the emergence of locality out of the parametric-tangent space. Indeed the notions of locality and extension are made dual.
It is the interpretation of QM itself that suggests that decoherence could yield the "unfolding" of space-time, the emergence of locality-extension, in the very same sense we are discussing it here.
Incidentally, if QFT was a tangent space in a profounder sense than what assumed above, it would make sense that any field would fail to be "gravity" at the fundamental level: tangent spaces can't properly deal with circuitations, extensions do. See the twin problem in SR, SR can't solve it because it does not know what a change of speed is, even when it does know what the correct computation would be... if it only could recognize the change of speed! A tangent space only deals with pass-bys, not returns.
This suggests that, perhaps, we might want to pause, make a step back, and reconsider our computations in QFT figuring out if there is a distinction to make between a parametric (tangent space) computation and an extended (relating to the extension space) computation. Mmmm, we have loops in there and they are where we need renormalization... has it anything to do with this?!? Don't know, let it hang here...
Can someone explain why the entanglement is set to inversely proportional to distance (instead of inversely proportional to the square) when defining a quantum system such that you can derive 3D space?
Is splitting worlds entropy in some way? Is time just splitting worlds? I'm tripping ballz. Are we just snapshots with a brain at each snapshot telling us we are a person with continuity?