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.
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.
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.
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.
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.
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!
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.
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
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
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!
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’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!
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.
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.
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 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.
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.
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.
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!
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...
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.
"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
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 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,
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.;)
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
@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"?
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?
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.
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 👏
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...
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.
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...
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?
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...).
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.
About the toy models of black holes... ok, well, it seems they became toy models for theoretical physicists at some point... my conjecture is that physical black holes are not Schwarzschild black holes, i.e. not sink holes, but rather geometrodynamical cavitations. But perhaps this does not even affects the theoretical toy models? Anyhow... The reason why I think this is the principle that the physical geometry is, by definition of 'physical', the one that we observe, or at least the one computed from the energy-mass where we observe the energy-mass being in our reference system. So the Schwarzschild's BH assumes the mass-energy in some point, then computes that, in the resulting geometry, we observe (yes, from the outside!) mass-energy accumulating on this side of the event horizon, which contradicts the initial assumption if we maintain the principle that we have to put in our model the mass-energy where we see it, according to our reference system, and that the BH was born in the same way that it increases its mass. This suggests to me that Schwarzschild's BH is a mathematical solution that is not observable, i.e. not physical, and the likely physical solution is that of a geometrodynamical cavitation (I think the geometry is not well defined inside the horizon in this case, according to GR, which I intend as there is none inside). Ok, I know, Alice falls in and she supposedly passes the horizon at a finite time. Still, Bob sees her falling in forever. The point is, they don't agree on how much time passes between events, but they do agree on events, and falling into a BH is "after" this universe for both Alice and Bob (Why Alice never looks up while she falls in? She always seems to miss the chance to see the whole history of the future universe flash in front of her eyes! Now, wouldn't that be hot? :P *
I can follow Neil, Brian, or even Einstein for that matter but I really have difficulties grasping Sean. If you ask me the universe is eloquent, simple and beautiful, it doesn't have to be so antiquated.
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.
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!
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 thought that the joke about drunk guy who lost his keys and is now trying to find them under a street lamp even tho he didn't lose them there is a Serbian joke. My grandfather told me that joke several times when I was really young. I had no idea that it was an international thing.
I don't understand how an entire universe can branch off still containing all the energy. And branch off again till nearly eternity while presumably keeping all the stuff in it? I just can't come even close to imagining the reality of such a thing. It's hyper un-intuitively.
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?
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?
A more humane version of the Schrodinger thought experiment is fine and dandy, but how do you verify that the cat isn't sleepy when you start? If it nods off prematurely, you've got a problem, which isn't the case if you stick to cyanide.
The chemical reactions of dead cat's decomposition should occur wether you look into the box or not. Let's assume the cat had air and nutrients to stay alive for a year, before you open the box one year later. Let's also assume, the poisoning can happen at any point of the year. If the poisoning had happened at the start of the year, cat should be in rotten form at the moment you open the box. That also means, the cat cannot be in superposition at the moment you open the box, because the particles have to go through several chemical reactions along the time cat has been dead. What am I missing?
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
I found gravity in quantum theory using the hydrogen atom as a model for it. Something I found is the electrons size changes when it's orbit changes also two kinds of time (dilated) I can roll back the wavelength to the charge radius and the gravitational radius
![[LIVE] : ONE ลุมพินี 78 | คู่เอก "ปกรณ์ vs ฟาบิโอ"](http://i.ytimg.com/vi/LSOmgl0Th2c/mqdefault.jpg)
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
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.
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'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.
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.
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.
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
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 one of the few best thing that happened to the internet. I'm a huge fan of you sean ✌
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!
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.
This is by far my favorite episode so far!! Thank you Sean.
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
These podcasts are awesome ….specially the ones on physics. Looking forward to listening to more. THANKS!
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
I really like the intellectual honesty in his approach to quantum mechanics and the clarity of his descriptions.
Sean, this may be your finest hour.
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!
Did i just find a Sean Carroll's channel?! Thank you, TH-cam!
Your podcasts are wonderful, Sean and you are the most articulate science educator I've had the pleasure to listen to.
Really enjoying these solo episodes, Carroll is a legend.
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.
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!
Thanks Dr Carroll. I always enjoy your podcast. Very enlightning.
Khairul from Malaysia
One of my favorites eps, thanks much!
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.
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.
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 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.
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.
Just when I think I am out, many worlds pulls me back in...
but also doesn’t at the same time in another universe
Basically a free lecture on the latest research! Thanks!!
Your explanations are way better than any documentary I've seen on TV(like Discovery or National Geographic)
Thank You!
"Theoretical physics is all about trying it out". Professor Sean Carroll 2019.
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.
Well, I know what I will use my audible credit for!
That Jacobson insight/speculation is sweet.
Where Dr. Carroll makes me a believer in many-worlds.
Wow is it weird i have this in my head word for word very easily. Trip out. On quantum mechanics.
i bought the book and read it and then listened to it, now his lectures sink in more to me :)
When you get the blanket thing you can relax... because everything you could ever want or be, you already have and are.
Thanks Sean. I don't understand a word your saying but you state it with CONFIDENCE!
You are an EXCELLENT professor Sean. Thank you Very Much for your devotion.
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!
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.
As I hear this changes my life
This was as deep as a black hole. Intense! So amazing.
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...
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!
If this is in Barnes and noble tomorrow, I’m gonna grab it
"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
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 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,
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.;)
Thank you very much for doing these podcasts
U rule dude. - Nano Pharr, Texas 2019
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
YES!!! I have been looking forward to this talk on gravity and the new book coming out.
@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"?
Blows my mind every time. Great episode!
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?
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.
Sean, The drop shadow behind the MINDSCAPE text looks weird and misplaced. What is the shadow supposed to be falling upon?
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 👏
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...
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.
I wasn’t aware that Sean had a podcast. I love it
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...
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?
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?
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...
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.
About the toy models of black holes... ok, well, it seems they became toy models for theoretical physicists at some point... my conjecture is that physical black holes are not Schwarzschild black holes, i.e. not sink holes, but rather geometrodynamical cavitations.
But perhaps this does not even affects the theoretical toy models? Anyhow...
The reason why I think this is the principle that the physical geometry is, by definition of 'physical', the one that we observe, or at least the one computed from the energy-mass where we observe the energy-mass being in our reference system.
So the Schwarzschild's BH assumes the mass-energy in some point, then computes that, in the resulting geometry, we observe (yes, from the outside!) mass-energy accumulating on this side of the event horizon, which contradicts the initial assumption if we maintain the principle that we have to put in our model the mass-energy where we see it, according to our reference system, and that the BH was born in the same way that it increases its mass.
This suggests to me that Schwarzschild's BH is a mathematical solution that is not observable, i.e. not physical, and the likely physical solution is that of a geometrodynamical cavitation (I think the geometry is not well defined inside the horizon in this case, according to GR, which I intend as there is none inside).
Ok, I know, Alice falls in and she supposedly passes the horizon at a finite time. Still, Bob sees her falling in forever. The point is, they don't agree on how much time passes between events, but they do agree on events, and falling into a BH is "after" this universe for both Alice and Bob (Why Alice never looks up while she falls in? She always seems to miss the chance to see the whole history of the future universe flash in front of her eyes! Now, wouldn't that be hot? :P *
I can follow Neil, Brian, or even Einstein for that matter but I really have difficulties grasping Sean. If you ask me the universe is eloquent, simple and beautiful, it doesn't have to be so antiquated.
I think a (classical) state is rather defined by position and impulse than position and velocity. Just my 2 cents.
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.
Love the show Sean!
When a wave function branches into separate worlds, does this not violate the conservation of energy? Informative replies requested.
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!
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 thought that the joke about drunk guy who lost his keys and is now trying to find them under a street lamp even tho he didn't lose them there is a Serbian joke. My grandfather told me that joke several times when I was really young. I had no idea that it was an international thing.
May the Force/wave function be with you :)
I would love to take part in an undergraduate course and lecture taught by you
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.
If the matter in the black hole is as dense as it could possibly be then the area could only be one size and volume for any given amount of mass.
I don't understand how an entire universe can branch off still containing all the energy. And branch off again till nearly eternity while presumably keeping all the stuff in it? I just can't come even close to imagining the reality of such a thing. It's hyper un-intuitively.
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?
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?
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
Yes. your wonderful Sean.
A more humane version of the Schrodinger thought experiment is fine and dandy, but how do you verify that the cat isn't sleepy when you start? If it nods off prematurely, you've got a problem, which isn't the case if you stick to cyanide.
The chemical reactions of dead cat's decomposition should occur wether you look into the box or not.
Let's assume the cat had air and nutrients to stay alive for a year, before you open the box one year later. Let's also assume, the poisoning can happen at any point of the year. If the poisoning had happened at the start of the year, cat should be in rotten form at the moment you open the box.
That also means, the cat cannot be in superposition at the moment you open the box, because the particles have to go through several chemical reactions along the time cat has been dead.
What am I missing?
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
Hi Sean, Quantum all the way !! keep it Up
I found gravity in quantum theory using the hydrogen atom as a model for it. Something I found is the electrons size changes when it's orbit changes also two kinds of time (dilated) I can roll back the wavelength to the charge radius and the gravitational radius
My favourite episode so far.
I'm a many worlds believer now.
Can't wait to buy Something deeply hidden
What if I used a can opener like it's dinner time instead of opening the box - Does that count as observing?