#science #physics #ideas The Biggest Ideas in the Universe | 7. Quantum Mechanics

#science #physics #ideas The Biggest Ideas in the Universe | 7. Quantum Mechanics 311,898 viewsMay 5, 2020 Sean Carroll 154K subscribers The Biggest Ideas in the Universe is a series of videos where I talk informally about some of the fundamental concepts that help us understand our natural world. Exceedingly casual, not overly polished, and meant for absolutely everybody. This is Idea #7, "Quantum Mechanics." We talk about the quantum recipe -- the basic ingredients of wave function and Schrödinger equation, and how they are mixed together -- leaving deeper interpretational issues for later. My web page: http://www.preposterousuniverse.com/ My YouTube channel: https://www.youtube.com/c/seancarroll Mindscape podcast: http://www.preposterousuniverse.com/p... The Biggest Ideas playlist: https://www.youtube.com/playlist?list... Blog posts for the series: http://www.preposterousuniverse.com/b... Background image: https://woowpaper.blogspot.com/2020/0... #science #physics #ideas #universe #learning #cosmology #philosophy #quantum 634 Comments rongmaw lin Add a comment... Squatchy McSquatchsquatch Squatchy McSquatchsquatch 2 years ago (edited) You literally have no idea how much I appreciate that you're putting this out during this period of time, and how much I enjoy being able to follow along with it. I love that you show how calculus is integral (pun intended) to all of these ideas and show a few examples, but that your focus is on the ideas themselves, not trying to explain 5d tensor homework problems to people like me who C'd my way through calc 106 the second time through... That's how you get people EXCITED about these big ideas. I am excited, because you sir, are doing an amazing job! Thank you. 269 ghoulunathics ghoulunathics 2 years ago we are honored to have a man like you having his own youtube channel. 30 Martin Wilson Martin Wilson 2 years ago You can tell by the comments that Sean has reached a Feynman-level of teaching and inspiring. These videos will be referred to time and time again. We are watching history in the making. Despite them being lectures about 'we don't know', The honesty he provides us laymen trumps the deception laid on undergraduates. Devoting his career to turning this big ship around, in order to save future generations going wildly off-course. Cheers Sean. 133 david weissmann david weissmann 2 years ago great kudos to you for using your time to put out these "classes" - super good presentations - clear and concise and at the right speed and depth 29 Arvin Ash Arvin Ash 2 years ago (edited) Fantastic video that summarizes not only what QM is all about, but also how it came about. Brilliant! Should be required viewing for any student of quantum mechanics. 86 Houston Saft Houston Saft 2 years ago You are now one of my favorite humans for doing this. 53 Kayrosis Kayrosis 2 years ago That I could generally (though not perfectly) follow along with this just by listening, and not even watching is a testament to how well you're translating this into terms laymen can understand. This is a fantastic series you're doing Mr Carroll, I'm sure countless people will turn to these in the coming years. 5 Kieran Garland Kieran Garland 2 years ago Would still really love a primer on the classical ideas of electro-magnetism and statistical mechanics. Have never developed a strong enough intuition for either of them. That said, this is great episode in the series. Thanks again for sharing these, they're really so useful and so enjoyable. 5 Jeff Wells Jeff Wells 1 year ago What a great video! You clarify so many things that I was fuzzy about all along and I only wish you were there when I was ploughing through this stuff 50 years ago! You also touched on the difference between "observation" and "measurement," something that I wish scientists had done from the beginning, because to the uninitiated an "observation" implies an "observer," and that implies a conscious mind to a lot of people. This has led to travesties like Deepak Chopra telling people that "they create the universe" but simply looking at it, which is of course barking nonsense. I wish science could change its terminology and change observation to measurement, but it's probably too late for that. In the same vein, the use of "theory" to label what is actually an "explanation" of a set of related facts has resulted in encouraging millions of ignorant religious types to insist that scientists are only guessing about these things. I look forward to more of these videos! 13 James Bra James Bra 2 years ago The only thing better than free physics lectures is physics lectures from the master, Sean Carroll, himself. Great day! Perhaps if this pandemic produces anything positive, it is a new Isaac Newton with all the answers lol. 31 zeyno lee lewicki zeyno lee lewicki 2 years ago It's extremely infuriating to come across videos like this, now that I graduated from high school. I can see how a waste of time my physics classes were compared to this. My teachers had either no real understanding of the topic or teaching in general. It's oftentimes forgotten how important it is to set the context before delving into subjects that are new and foreign to our understanding of the world we live in. And this is just a brilliant example of a high school level introduction of a subject!! thanks:) 31 Grow-Nanny Inc Grow-Nanny Inc 2 years ago I've been following you since your talks on quintessence and ive listened to 'The Big Picture' and 'Something Deeply Hidden' at least 50x each. Thanks for being my mentor all these years. 13 Sandip Chitale Sandip Chitale 2 years ago (edited) Sean, can you please clarify definitively that even in Copenhagen interpretation whether or not the “observer” or “measurement device” in a quantum experiment, does or does not have to be a conscious entity like a human. As I understand it, “observer” is simply a macroscopic thing that interacts with a quantum system – which causes the “collapse” of the wave function according to Copenhagen interpretation. Did any one of Copenhagen club members ever say that “observer” has to be a conscious entity? I know that Jon Von Neumann and Wigner proposed that “observer” has to be a “conscious” entity. But later Wigner changed his mind. How many modern scientists use the word “observer” to mean “conscious” entity? Could you please convince your fellow scientists to clarify the word “observer” as it is used in quantum mechanics. IMO the use of the English word – observer – for the measuring device in quantum experiments, was a unfortunate choice and has caused countless amount of mischief by new age gurus like Deepak Chopra. I am really annoyed by it. I am surprised that even at respectable conferences like FQXi there is a discussion about “observer” in quantum mechanics as if it needs to be a conscious entity. Or is it still true many scientist think that “observer” has to be a conscious entity? It is obviously true that a macroscopic conscious entity can play a role of “observer” not because it is it is conscious but because it is macroscopic. 14 Ian X Ian X 2 years ago Awesome video, thanks! I really appreciate when Sean distinguishes what is know from what is theorized. It’s frustrating when other videos on quantum mechanics state everything as absolute fact when in reality, physicists are trying to workout some of the finer details. Looking forward to the next video. 1 V-LOGI V-LOGI 2 years ago Sean, you’re the best. Thanks for doing these videos- appreciated. 6 dmfrench dmfrench 1 year ago You wouldn't know what I love about Dr. Carroll? He's not perfect, and he doesn't try to hide it. I always thought such a great mind would be superhuman, but not so! He gives me hope. 9 Lars Alfred Henrik Stahlin Lars Alfred Henrik Stahlin 2 years ago Thank you so much for this! You're an astoundingly good teacher 6 Commander Shepard Commander Shepard 1 year ago I’m taking my formal course in quantum mechanics this fall, this was a great overview of what I learned in modern physics. Thanks for the review Dr. Carroll! 1 Kami Shinigami Kami Shinigami 2 years ago Amazing series of lectures :). This feels like the adult version of the weekly shows (Star Trek with my grandpa) we were waiting for when we were kids :). Can't wait to see the next video! Many thanks for these inspirations! 3 Zero One Zero One 2 years ago Phenomenal episode, greatly appreciated. 8 Tony rinaldo Tony rinaldo 2 years ago Love this stuff Sean! And you explain it so innately and in a way that’s relatable and comprehensible. Thank you sir! 1 Sebastian Clarke Sebastian Clarke 2 years ago (edited) I can't thank you enough for how much you've contributed towards keeping so many of your students focused through these uncertain times. I offer my immense gratitude for all your hard work throughout this crisis!! Here are a few wave function questions I would like to offer up: Can a wave function be collapsed by another wave function/virtual particle or must it be an actual particle? Does the wave function extend across all of the splitting many worlds born from wave collapse and all the bubble-verses born from inflation? Is it correct to think that there is only one wave function and that no single part of it can ever fully collapse? Is time reversed matter expected to merge diverged wave functions? Would it be correct to think that the most collapsed "part" of the wave function would be the matter furthest away from us in time? 1 Troy Tunello Troy Tunello 2 years ago I really appreciate the way you explain things. Keep it up! 2 Griffics Griffics 2 years ago I'm loving these videos – thanks so much for making them. 1 philip rogers philip rogers 1 year ago Brilliant and truly inspirational lectures. You have an amazing talent for explaining complex ideas simply. I love how you put the maths to one side to facilitate a deeper understanding of concepts and clarify what the maths is actually describing. 1 Derek Aegerter Derek Aegerter 2 years ago Thanks, Dr Carroll, for doing these! I loved From Eternity to Here and listened to it on several long lonesome road trips to and from university. Vlajkonino Vlajkonino 2 years ago Thanks for great series so far, Sean. For the second part of quantum mechanics, I would suggest you touch on double slit experiment. It reveals some of the strangeness of quantum mechanics, and I would love to hear your interpretation of it. Just a suggestion, will watch and enjoy anyway :) 1 virtual82x virtual82x 1 year ago Great stuff. Sean, you're an ace. How do we go from this into a more detailed explanation of how these formulas were extrapolated? swOOp swOOp 2 years ago Thank you for these wonderful layman sessions! 2 Celestial Aeon Project celtic music & epic music Celestial Aeon Project celtic music & epic music 2 years ago Thank you for this <3 Very clear and profound! Thomas Gutierrez Thomas Gutierrez 10 months ago Great video! Sean seems almost physically pained by having to set up and explain the standard textbook quantum framework, even though it is amongst the best explanations on the topic I've seen AndyBeans AndyBeans 2 years ago (edited) I'm not falling for that "You can watch cloud chambers..." trick again, I lost a whole day looking at tracks from all sorts of particles, totally mind-blown. 14 Dražen Buljovčić Dražen Buljovčić 2 years ago Sir, so much respect for your work! Love the creative idea for videos! 1 Kirit Dave Kirit Dave 1 year ago Superb explanation. the best ever heard! thank you, Sir. Answered so many of my doubts that had bothered me for so long. Sam Harper Sam Harper 2 years ago I couldn't agree more with what you said at the end of this video about understanding reality vs. making predictions. It's refreshing to hear you say that. 4 Kevvers Kevvers 1 year ago (edited) I haven't felt this inspired to continue pursuing an interest in such a long time. Having even a somewhat clear idea of where the line is drawn between what we do know and what we don't is such a motivating sensation. 2 Rob Lindsey-Nassif Rob Lindsey-Nassif 1 year ago It's a privilege to hear Sean Carroll. He's brilliant yet down-to-earth. What a thrill. 1 E H E H 2 years ago I just wanted to echo my thanks for putting in the time and effort to create these videos. I'm really enjoying watching these while I am stuck at home like so many others. Stay safe! Drop Deer Drop Deer 2 years ago Q: what is the length of a photon? Is it several wavelengths? Is it possible to measure it? 1 Simos Hajiraptis Simos Hajiraptis 1 year ago Exceptional video! Thank you for all this effort and keep doing such works! Stelios P Stelios P 2 years ago Not only is Dr Caroll releasing great content but it just keeps and keeps on coming. I love it :D Thank you once again Dr Caroll. 3 JJ Coulter JJ Coulter 2 years ago These videos are so great. Thank you so much for making these. 1 MightyCaucasian MightyCaucasian 2 years ago (edited) Great video. I had a thought regarding what measurement could be. I thought about measurement as being analogous to a render distance in a video game. You measure everything in your render distance, where everything in that vicinity collapses into a particle, and everything outside of your render distance acts like a wave. 1 mansoor m mansoor m 2 years ago (edited) Hi Sean, I just wanted to thank you for your fascinating book "Something Deeply Hidden'. Picture of the book is cover photo of my Facebook. The Part Three worth the whole money, a topic I have been waiting for, for many years to read. GREATLY APPRECIATED! willnzsurf willnzsurf 2 years ago Superb. I'm getting much more comfortable thinking about the quantum mechanical way things really are. This has been especially helpful. Thanks a lot, Sir!!💯 Doug Cowell Doug Cowell 2 years ago Yep, I had all this in my physics classes in college. And I look at it and I can appreciate what's being said. Love the probability wave stuff. But then we get the experimental results that come with some of this - like the different combination of three light polarizing filters - and it all goes out the window and my brain melts. My way of saying that I can't wait for the next part. :-) 1 Mikkel Mikkel 4 days ago Thanks to very good presentations of quantum mechanics and the corona pandemic, a lot more of us now don't understand quantum mechanics. Today you don't need to be a physicist to not understand quantum mechanics. Vikezupa Vikezupa 2 years ago Thank you for putting these concepts in the grasp of non-physicists. It’s such an interesting field. pizzacrusher pizzacrusher 2 years ago Another fantastic, well delivered, fascinating Idea. Thank you!! (as an aside I was hoping double slit experiment would come up, since I've been waiting my whole life to ask a question about it...) David Hughes David Hughes 1 year ago Great Summary-Loved it! I agree completely with your point on reality. The wave function does describe the real universe and we should all agree on that. Fascinating stuff!!! Jeff Bass Jeff Bass 2 years ago (edited) Amazing video! I really hope in the next video you talk about where the discrete "particle" comes from in the many-worlds interpretation. Kony Bornie Kony Bornie 2 years ago Thank you a lot for this lecture, doing this for us and all future generations... p b p b 1 year ago Thank you so much for trying to help us understand. I appreciate these so much. 1 Mike Literous Mike Literous 5 months ago Such a good explanation, love it Sean Bruno Teixeira Bruno Teixeira 2 years ago Question: how did quantum mechanics allowed us to make transistors? Thank you 3 Isabel AB Isabel AB 2 years ago Still trying to get my head around this! I wish I spent more time think about this in my youth. Thank for expanding my universe 27 Kaiku Nymous Kaiku Nymous 1 year ago I learned something about quantum mechanics. This is amazing! Mark Conrad Mark Conrad 1 year ago Sean you're the best! Btw every time someone explains quantum mechanics they always end up sounding apologetic lol. But I really appreciate the rigor and humility. The worst "ideas" are lazy and arrogant. 1 Guy XMAS Guy XMAS 2 years ago Awesome science, explained extremely well! Serkan Topcu Serkan Topcu 1 year ago Dear Sean carrol I would like to thank you for sharing your knowledge. The way you explain everything is super . I hope you keep going on like this Walter Staley Walter Staley 1 year ago Fabulous discussion! Thank you so much! thom1218 thom1218 2 years ago Glad to see you're embracing youtube's video format to deliver great content beyond the podcast format! Katherine Templeton Katherine Templeton 1 year ago Wonderful video!! You have an amazing ability to make very complex subject matter understandable to the average person. Thank you! Bill Bill 1 year ago Just fascinating to see the math in action. Mind blowing how complex nature is and how man has tracked it down to the nth degree. Thank you. decobocopithec decobocopithec 2 years ago (edited) Question: Hi Sean, If I understand correctly particles are excitations of their respective fields. My first question is, what is the relation between spacetime and the gravitational field, are they the same? My second question is, if existing means being in spacetime, is spacetime (or the gravitational field) the thing that gives existence to all the other fields, and if yes, how? Is it correct at all to say that spacetime interacts with them? So what I would like to know is, what is the connection between spacetime and the fields. Thank you! 1 Dan Noc Dan Noc 1 year ago A fantastic lesson, thanks. Allan Zed Allan Zed 2 years ago Fantasic series - I'm loving it and learning so much. I'd like you to comment on David Bohms idea (if I interpret it correctly) that the quantum wave could be the smallest unit of consciousness and that all objects (from atoms, to molecular formations) are different manifestations of these conscious interactions. Sounds weird but so does quantum mechanics. A Kumar A Kumar 2 years ago Oh my God this is the hardest thing ever concept for the layman to understand, hopefully my limited understanding will be improved, Thank you Sir. 27 DontPressTheRedButton DontPressTheRedButton 9 months ago (edited) Wonderful to have such free access to your mind with all your videos Sean. Extraordinarily generous. Tuncay D Tuncay D 2 years ago 12:24 "We have ultraviolet, which is even bluer than blue." - Sean Caroll, 2020 57 Drop Deer Drop Deer 2 years ago Q: Is the "quantumness" an intrinsic property of the electromagnetic wave, or it is a property of matter which interacts with the wave? 2 Steve Seamans Steve Seamans 1 year ago Sean, so good! I wish I was back in school. Seems like this subject really pushes your buttons more than other videos you’ve done. I really liked your podcast with David Albert. I think you’re zeroing in some real understanding. Peter Lampkowski Peter Lampkowski 2 years ago Absolutely great lecture, for some reason it let me understand things I've new about but I didn't understand them :) cheers Mate tomahzo tomahzo 1 year ago (edited) 1:00:38 : Hah, that's amazing. I've taken the undergrad courses on QM (long time ago) and also fourier analysis (which is something I like to think about more than QM to be honest ;)) but it never clicked that the Heisenberg uncertainty principle could be connected to the relationship between time and frequency that way. Specifically, what wave functions of highly determinate positions vs. highly determinate momentums look like and how they look similar to a sine representation in time vs. frequency. Maybe I knew that way back when but I certainly don't remember thinking about it that way. Because I already know quite well the uncertainty between representing a signal in the frequency domain vs. representing it in the time domain. You get smearing in one domain if you increase the precision in the other. (in order to get a perfect spike in the frequency domain you'd have to have an infinite sine wave in the time domain, hence you have no concept of where you are in the time signal but you know perfectly well where you are in frequency) I get the feeling that I've forgotten a lot of the fundamentals and that there is a lot of maths that describe that relationship in more general terms. I guess I need to go back and refresh my memory (unless someone can point me to the foundational maths that connect the two) Regardless, that's a fantastic point you brought up there! Thanks a bunch for that! 1 Bounceback stfc Bounceback stfc 1 year ago Absolutely love it ! More please . Leon Van Dyk Leon Van Dyk 1 year ago Brilliantly helpful. Thanks Sean. H BOL H BOL 2 years ago Hi Sean, thanks for amazing explanation of QM .. also what software u used for blackboard if you don't mind Roy de Visser Roy de Visser 2 years ago thanks great job I understand more about the concept and the math. I picture the electron orbit as a bubblelike form and when we measure it, that bubble bursts. I look forward to learning more ! D None D None 1 year ago Yep, always brill. Thanks. One question I guess I'd ask is... If the electron is observed as a particle as it passed though the cloud chamber, does it ever go back to being a wave... Like, when it's no longer "being observed"? josh horejs josh horejs 2 years ago (edited) This seems to be working for me. I am an ee student and this is helping me grasp things that I haven't had time to investigate on my own. Thanks for the quantum physics cliff-notes. While we are here and since you have officially covered space-time and electrons, please briefly explain the one-electron universe. you tou you tou 2 years ago Imagine having a teacher as great as Sean, get a random job and then find out how not great the rest of the world actually is Paul Perkins Paul Perkins 2 years ago Watching this, find myself picturing Classical Mechanics as a kind of lost Eden from which physicists have been expelled, but always long for. 3 CleerPond CleerPond 1 year ago Mesmerized; Had attended four graduate schools in engineering, your explanations here is among the best one hour I spent in a lecture. Bravo Sir! marijica marijica 2 years ago Omg thank you sir! I never understood the wave function until now 1 JK Life JK Life 2 years ago Q: Does decoherence provide a solution to the measurement problem? I.e., is a measurement event an event that causes decoherence? (independent of whether you prefer MWI or Copenhagen or whatever). 1 Abdennour abdennour Abdennour abdennour 1 year ago That is an excellent lecture as your previous...please can you do a video lecture on Bohm theory especially to clarify the hidden variables....thanks Dubl_D Dubl_D 1 year ago This reminds me of the simulation hypothesis in the way that rather than having every part of the universe being rendered at once, like what we see as particles, only by observing are things they seem to be existing as particles rather than waves. Spencer Delallo Spencer Delallo 2 years ago Loved your book. Keep the content coming even when the world gets better lol LA6UOA LA6UOA 1 year ago You are my hero! Thank you, Sean! barry wilmot barry wilmot 1 year ago I so wish I'd had you Sean as my Physics teacher at university. Yes, these topics were covered in my undergradute course but your explanations are so much clearer. I finally understand Heisenburg's uncertainty principle - thank you :-) jim kane jim kane 1 year ago How privileged are we that we can watch quantum mechanics lectures from Sean Carroll for free! 1 weiniesail weiniesail 2 years ago (edited) Great video... Physics student of the 80s here... it never occurred to me to picture the DeBroglie wavelengths of particles to be on a string with vibrating nodes which made it clear why 2(pi) is so fundamental in the nature of the universe and appears everywhere! It almost makes me wonder is 2(pi) is just slightly more fundamental in a sense than (pi) itself. Why was (pi) chosen as the ration of the circumference of a circle to its diameter as opposed to it's radius? (edit... this is a rhetorical question). 1 TheKoopaKing TheKoopaKing 2 years ago Question on the Copenhagen interpretation: From what I've learned about QM, it seems like it's impossible for a particle to have a definite position. So when we make a measurement and collapse its wave function, how "collapsed" does it get? Does the particle actually take an exact position at the time we made the measurement, minus the uncertainty we get from our measuring apparatus? Vaguely related to this - I've heard electrons have no size. Is there a cool classical visualization to understand how something with no size can become localized, or even be measured? 1 Jainal Abdin Jainal Abdin 1 year ago Love the virtual blackboard! Regarding the measurement problem, I always think of the Wavefunction as a mathematical interpretation of reality. Its collapse when being measured is a superposition of all Wavefunctions in the system being measured. Moreover, the measuring device itself is a Wavefunction and contributes to the final observation. The observation isn't predictable because we cannot repeat the Wavefunction created by the measuring device exactly. Sandra Prado Sandra Prado 1 year ago Very inspiring. Thank you! Dr10Jeeps Dr10Jeeps 1 year ago Excellent! I could listen to Dr. Carroll for hours. Oh, wait, I already do. John P John P 2 years ago Best introduction to QM I've seen so far. 5 Charlie thee Barker Charlie thee Barker 2 years ago Great show love the videos, just dont long time viewer since the JRE shows! 1 Antonio Fonseca Antonio Fonseca 1 year ago Out of laymen's curiosity I watched your Lecture #7, Quantum Mechanics (and propose to watch a few more of interest to me) and found it fascinating, even if a whole of the material went over my head. I wanted to tell you how very nice of you it is to devote your time and effort to make physics (some aspects of it) available to ordinary members of the public. Thank you very much for your generous offer of time and expertise. Martin DS Martin DS 1 year ago My favourite lesson so far professor. pjosip pjosip 1 year ago Thank you for this explanation! Anita Thorsteinsson Anita Thorsteinsson 1 year ago Thank you so much for doing these Sean. I only did maths and science until year 10, because I never really understood the point. In my maths classes, there was usually an utterly bored teacher who would scratch his balls while staring out the window and pointing to the blackboard. I had no idea what the point of learning any of it really was. There were some numbers and some letters and some angles and apparently I was going to need this for when I did a spot of carpentry or needed to pay for things. Meanwhile I drew pictures of bunnies and people on a notepad and waited impatiently for my art class, or for the time when I never had to do any of that useless crap again. Meanwhile I had some unrelated questions about the universe that I thought about constantly. For example, how is this all put together? What is all this stuff, how does it all get made, what is reality? How on earth do people figure out how far away planets are, what is in their atmosphere? And then on a smaller scale, what the hell is a wave function and a Hamiltonian and how on earth can something only really ping into a definite existence and location when measured? I wanted to know the answers to all of these questions. It turned out these were related to maths and science after all. I can’t help thinking how much more I could have known about the universe by now if someone had explained some things to me, like what the real purpose of maths and science was. But no-one did, and there was no YouTube in the early 90’s. This is where you come in. I can’t even begin to explain how clearly you have explained what was previously inaccessible to my brain. Everyone says to me that I have to start from the beginning and learn the basics and then go from there. But my brain works in the opposite direction. I want to know the answers to the big questions and then work backwards to understand what it all means and how someone worked this out. Obviously I can’t do any of the calculations but I now understand that it’s not the numbers and the letters which are the point, but what the letters actually represent. I didn’t even understand that. Now when you’re writing a calculation on your board I’m thinking, I know what you mean when you’re saying that. I understand why it is that things are kind of nowhere until we pin things down by measuring them. It just is that way and it’s bloody amazing. I now understand so much more about the universe and how people figured it out. So, thanks. I really appreciate all your efforts. You are a kick-ass teacher. 1 Dr. Mouser’s Lessons Dr. Mouser’s Lessons 1 year ago This is great stuff. Thank you for your time Amere Mortal Amere Mortal 2 years ago This is getting good now. I like that you take the time to dispose of the pseudoscience. There’s so much of it when you get into quantum physics. George Komarov George Komarov 1 year ago I'm a mathematician, I know what Hilbert space is and how to solve partial differential equations and so on. But this is the first lecture ever that finally made me understand what wave function, Heisenberg principle etc. really _mean_. Thank you so much. It's a shame your videos aren't getting as many views as they deserve, they're very underappreciated. Calin Werlein Calin Werlein 2 years ago A huge gift for society to have people like you. Please keep it up Joe schmo Joe schmo 1 year ago (edited) bought it as an ebook after i watched this video, i understood...some of it I did not go to college and am not that bright, and I could still follow it, a great book Sandip Chitale Sandip Chitale 2 years ago (edited) Thanks for this Sean. If the Wave function is a continuous function - as the bell curve looking curve Sean showed in the example - spread out over space and if a measurement can find the particle at any one of those points – then in the many worlds interpretation it means that the universe will have to split into infinite branches for every possibility not only two branches. Is that correct way to think about it? Jai Bellare Jai Bellare 1 year ago The best explanation of quantum mechanics that I have ever seen Hugo Hugo 1 year ago Great video, Sean! Thanks a lot Ranjit Naik Ranjit Naik 2 years ago Very nice way of explaining these complex topics. I will learn and teach my daughter now. God bless. KAĞAN NASUHBEYOĞLU KAĞAN NASUHBEYOĞLU 2 years ago Thanks a lot for lectures Mr. Sean Caroll. Eric Velasquez Eric Velasquez 1 year ago One of the best Quantum Mechanic lecturer. Lambda Lambda 1 year ago Fantastic stuff! Feel honored to hear it. Mittelwelle 531 kHz Mittelwelle 531 kHz 2 years ago (edited) I think this series is great and I love to watch Sean Carroll explain all this stuff in a mostly easy to comprehend language which also has the potential to reach a lot of interested laymen. (And he does so much in the same style as Heinz Haber did it 50 years ago in German TV in his series "Der Stoff der Schöpfung", only with a bit more occasional math added.) A maybe minor issue I still have with this episode is his frequent use of the phrase "if we look at something" (like the electron). First of all it puts the process of "looking at something" in the category of an "activity", even more the use of "at" attaches the connotation of something "extending out" from the person who DOES look. (Maybe that categorization is even anchored in our intuition as you can still observe in 3...4 year old children who think by just closing their eyes they become invisible, somehow.) So, In my opinion "looking at" transports an (in that context) quite unlucky wrong meaning subconsciously. Especially to laymen not trained to immediately translate it to something different, what Sean Carroll probably does without noticing and therefore is not sensitive for the problem. But the active part of "looking at" ends with turning our head, moving our eyeballs, and adjusting the lens to get a focused image at the zone of our retina where we can resolve the details of the "looked at" object best. From that moment "looking at" becomes passive: we wait for photons to be turned into electrical impulses travelling along the nerves. And as such photons are at the core of what this episode covers we should not use the active voice combined with a pronoun associating the activity with a living, conscious being. By the phrase "only if we look at" laymen may be lured into a thinking (as I said, partially by a subconscious process) that if a scientist who sets up an experiment and never looks at the results (maybe dies from a sudden heart attack before the experiment finishes) it might change the way in which some electron interacts with matter and that this particular electron stays on to be a probability function. If there's an automated recording device storing the result of this experiment (during which the scientist suddenly dies) but nobody replays and "looks at" the recording for years everything still has happened as it has. And it still has if the recording was destroyed before looked at it only once. And if the wiring to the recorder would have been set up wrong and there hasn't ever been a recording it still would not have influenced the interaction the electron had with the sensor placed in his path. The most probable outcome of the use of "look at" is we will have people claiming the collapse of the wave function would not happen until a conscious being takes notice. (I've heard this claim more than once, even by very educated people, who have a tendency to fill their spare time with speculating what makes human consciousness so special.) Contrarily (or at least this is my understanding) there's a lot of "looking at" going on in the universe, all the time and everywhere, just because matter and energy is present all around, available to interact with other matter and energy, completely outside any experiments specifically set up to "look at" something and even without any living being around, intentionally measuring something, within billions of lightyears. Joe schmo Joe schmo 1 year ago my head hurts, i am dumb...but you have inspired me to keep watching and to read more on this subject and all of the others you have taken the time to explain. Thank you! Doug Plumb Doug Plumb 11 months ago Great explanations, a few more equations would clarify, I mean generally through all these videos of which I've seen about half so far. Some notations in QM make it confusing. life42theuniverse life42theuniverse 2 years ago 49:00 A dedicated video to examples of measurements/collapse would be a good follow-up video. Reviewing what literature has to say about people, animals, or apparatus collapsing the wave-function. Harsh Kopulwar Harsh Kopulwar 2 years ago Hey Sean I have a question: What's the universe expanding into? and is the universe finite or infinite? theosib theosib 2 years ago It seems to me that one reason tat measuring a quantum particle makes it look point like is that our measurement instruments are actually signal amplifiers. The particle interacts with the detector, and then the detector has to turn that tiny interaction into something like an electric current that we macroscopic creatures can detect. A lot of information is lost in that amplification process. james james 1 year ago Thank you for the searies Dr Carroll. I am getting alot out of it! wow Geoffrey Byers Geoffrey Byers 2 years ago Brilliant. This has never been done before with such a balance between some symbolism (maths) and 'understanding'. Fredrik Fredrik 10 months ago For the Collapsing part, it seems to me that if we could accurately capture the state of the wave function of the entire environment, we should be able to predict where the 'particle' is going to be at the next step? Atbinix Atbinix 1 year ago You are awesome! These videos are my daily joy 😊 thomassaurus #science #physics #ideas The Biggest Ideas in the Universe | Q&A 7 - Quantum Mechanics 85,627 viewsMay 10, 2020 Sean Carroll 154K subscribers The Biggest Ideas in the Universe is a series of videos where I talk informally about some of the fundamental concepts that help us understand our natural world. Exceedingly casual, not overly polished, and meant for absolutely everybody. This is the Q&A video associated with Idea #7, "Quantum Mechanics." Mostly it's about the double-slit experiment, and why the wave function isn't just a cheap tool for calculating probabilities. But then at the end I get into the weeds a bit talking about the sense in which quantum states form a vector space. My web page: http://www.preposterousuniverse.com/ My YouTube channel: https://www.youtube.com/c/seancarroll Mindscape podcast: http://www.preposterousuniverse.com/p... The Biggest Ideas playlist: https://www.youtube.com/playlist?list... Blog posts for the series: http://www.preposterousuniverse.com/b... Background image: https://woowpaper.blogspot.com/2020/0... #science #physics #ideas #universe #learning #cosmology #philosophy #quantum 200 Comments rongmaw lin Add a comment... Seamus Bolger Seamus Bolger 2 years ago Thanks, Dr Carroll for the energy, effort and enthusiasm you put into this series of videos. It's very much appreciated. 70 ezsparky ezsparky 2 years ago Dr. Carrol, thank you for taking the time to explain things on the discrete/granularity issue. Your explanation helped a great deal. 23 Howard Maxwell Howard Maxwell 2 years ago (edited) Thanks for the discussion on Planck units. They’re often referred to in popular physics talks in ways that I took to mean discrete, but this clears up that misconception 12 Xavier Gamer Xavier Gamer 2 years ago (edited) Thank you for the lectures, you make me feel as if I have my own personal physics professor. I'm sure most of us watching feel that they too have their own personal instructor. And he is freaking great. 6 Brian Cannard Brian Cannard 2 years ago (edited) Thank you so much Sean! I guess some kind of a confusion when people ask "What is waving in psi?" is regarded to the observables, like energy _values_, spins, momentum, position (distance?) As you mentioned, the next video will be about measure and connection between QM and Measure theory (with Banach-Tarski paradox I hope?) but foreshadowing the answer to what's waving in psi and how outcomes of measuring things become positions and momentums. Thanks again! 1 Dean Batha Dean Batha 1 year ago Thank you, Sean. Your detailed explanation of how the wave function interferes with itself, in a way that a mere probability distribution can't, helped clarify several issues for me. Isabel AB Isabel AB 2 years ago This challenges me so much! Thank you! It is good to explore areas of study that are very different from ours 1 qclod qclod 2 years ago Love to hear Sean say "well... we have no idea" There's still much to discover! 3 Ken Bennett Ken Bennett 2 years ago At 38:22 Sean speaks my favorite Physics idiom, "It turns out that …". I've heard that since high school, and it always makes me think there is something that I will never know--right before "It turns out!" 8 Kdawg_ Kdawg_ 2 years ago I appreciated the math at the end. Reminded me of Brian Greene's daily equation videos. 3 Mike Roberts Mike Roberts 1 year ago Thank you for this series, it is very enjoyable and much appreciated. Have bought 'Something Deeply Hidden' to continue the fun! lilathrone lilathrone 2 years ago Thank You for calling us that stayed til the end hardcore:D Perfect video, Something Deeply Hidden just arrived on my shelf for a week now cant wait to start it, hope it has some math as well? 3 Zbigniew Zdanowicz Zbigniew Zdanowicz 1 year ago I love the math part, please do not shy away from it :) Also, the way you present, you talk about it - these concepts look so easy. Please keep up this great work. 1 David Campos David Campos 2 years ago Thank you Dr. Carrol for your double slit explanation. I had heard most of it in bits and pieces before. All of it at one time is much better. aman neelappa aman neelappa 2 years ago Thanks Sean. How to interpret a statement like "The wave function of the electron passes through both the splits" given that a wave function is a function in Hilbert space? In particular, given that the wave function has ordinary spacetime as its domain, does that constrain the Hilbert space in some interesting way? 2 ADITYA APTE ADITYA APTE 1 year ago Excellent video Sean as always. Question: In "what is waving" - I kept thinking if this is a 'new' way of looking at the concept of "Ether" ? (which was long discredited) Ola Byström Ola Byström 2 years ago This is amazing! Thank you Dr. Carroll! 1 pizzacrusher pizzacrusher 2 years ago (edited) OH THANK YOU double slit!!!!! I appreciate you talking about it so much!! - Does the detector by the slits affect the outcome in the sense that it exerts some force on passing particles (like an induction coil or something)? - if we assume the slit detectors are powered (so have a power input), and a data output, does the interference pattern persist if the detectors are powered, but the data output is un-monitored (or maybe not plugged in)? if the data output is somehow recorded to a table that no-one can read (heavily encrypted, maybe) does that count as an observation, and affect the interference pattern? - if someone entirely un-related to the above experiment later manages to decrypt the above data table, does the initial data taken from the interference pattern suddenly change retroactively to non-interference somehow?, OR! does the initial experimenter NOT get an interference pattern, and can thereby determine/conclude that the encryption will some-day become breakable (or maybe "hey, someone must secretly be monitoring the slit detector data outputs!"). These are very round-about ways of me asking about the measurement problem, and my way of asking the (admittedly poorly phrased) question "how does the wave function/electron/photon KNOW that the data output of the slit detectors is actually monitored?" Thank you again so much! Doug Cowell Doug Cowell 2 years ago Great addition to the last video. Thanks! Can't wait for the follow-ups. John Joseph John Joseph 1 year ago Love the explanation Sean. Thank you Picksalot Picksalot 2 years ago I'm looking forward to your video about measurement/observation, and any explanation on how or why that collapses the wave function. Thanks Vinicius Garcia Vinicius Garcia 2 years ago Sean singing at 27:35 is literally the best part of the video 38 Maria Esteves Maria Esteves 2 years ago Gostaria imensamente de ter o video traduzido! Sandra sandra Sandra sandra 2 years ago Thank you! what you and Brian Greene are doing is historic 1 Darth Plagueis Darth Plagueis 1 year ago This video series, plus your podcast, made me order ALL of your books on Amazon. I have always wanted to understand GR on a graduate level, so I hope your book is comprehensible for someone with a BS in engineering. Cooldrums777 Cooldrums777 2 years ago I have a degree in nuclear and electrical engineering and this is the best explanation of the double split experiment I have seen. Obviously nobody EVER bothered to teach me about how to conceptualize the wave function in graduate school. Thanks for this one Prof. 1 Hunter Bungay Hunter Bungay 2 years ago Thanks Sean! Great stuff. James Kent James Kent 1 year ago DAMN I love this series, Dr. Carroll. I'm a mechanical engineer and when I was in school (at ULL), my friend's grandfather offered a quantum mechanics elective for non-physics majors over a single fall semester. I unfortunately was not able to take it because it would have overlapped with my Machine Design lab. It's something I have always regretted; not only for the fact that those 3 credits would have given me enough for a physics minor. What you are doing with this and Mindscape is so hugely appreciated. Manuel Bevand Manuel Bevand 2 years ago Between this and Brian Greene's daily equation, my evenings are full of mathematical wonder (and confusion)! 1 Lambda Lambda 1 year ago Thank you! So glad you are doing these videos. lilit vehuni lilit vehuni 2 years ago After I watched video 7, I had the question. What is between 2 plank points and 2 plank moments? And the three answers I could think of were 1 nothing 2 another universe 3 we don’t know. Thank you for answering my question . I also realize that the question “between 2 points” may be meaningless. MadderHat MadderHat 1 year ago Strangely enough, as someone who left math back in high school, I really appreciated the math at the end to explain the wave function. The graphs help me put my brain in that way of thinking. John P John P 2 years ago Best explanation of the double slit experiment I've run across. Others seem to suggest that the particle "somehow" goes through both slits and interferes with itself. The wave function explanation makes perfect sense. Gedis2x Gedis2x 1 year ago The part about double slit makes me think that we are really in a simulation. Lemon Party Lemon Party 2 years ago I know you favor the many worlds interpretation, but have you looked into superdeterminism? 2 Go Away Go Away 2 years ago After talking about the "which slit" experiment I wish he had talked about the quantum eraser experiment. 1 Quantum Learner Quantum Learner 1 year ago hi i am really grateful that you have put your time and energy into this series of videos. my questions are 2. if the wave function is a function of space and time, where does it sit in theories where space and time emerge rather than being presupposed? second, re the measurement problem in QM i see that some experiments comment on an ability to 'measure' without collapsing the wave function. can you comment onn that? again my great thanks for you doing all this. pipertripp pipertripp 1 year ago At what size particle do we start to see a more classical pattern of impacts on the detector? calwz calwz 1 year ago If something is real (like the wave-function), it must be instantiated in the real world by some 'stuff'. What represents physically the wave function before the measurement? The particles of the parallel worlds should be there already to do that. Smgrn Marian Smgrn Marian 2 years ago (edited) How can one not fall in love with math and physics while listening to him...man I wish I had a math / physics professor like him in high school. ... Thank you Sean ! I might not get all you are saying but even so I'm loving the struggle to be able to. You are amazing! Pavlos Papageorgiou Pavlos Papageorgiou 2 years ago 10:00 If spacetime is completely smooth doesn't that imply the universe contains an infinite number of (classical) bits of information? 4 GrowKnow.how GrowKnow.how 1 year ago I have one particular way to see/explain wave function and would like to validate it here. It is the function that describes the path a particle take, from one interaction up to the next, and it is function of the particle's properties at start. The function is pretty much classical and deterministic from one interaction to the other. The problem is that we cannot access any sort of information during this interval in between interactions without creating a new interaction that would reset the wavefunction with new particle properties. That's what the slid barrier represents in the double slid experiment, a reset of the properties influenced by the shape and position of the slids, this reset configures the wavefunction to express the wave interference pattern. When added after the slids, the detectors interact with the particle, reseting the wavefunction with new properties, and this time without a doublle slid to re-interfere in the wavefunction, generating the "particle" pattern expected from two independent sources (each previous slid). Since we cannot set propper initial properties, is hard to see in experiments this deterministic aspect of the wave function, leading us to treat quantum mechanics as statistical. I would also consider this gap in between two interactions of a particle as the whole life of it, treating what it was past the first interaction and what it will be in after the second, as being other particles. The "story" told by this two-interaction-life-particle and its properties trough the wavefunction, generate the spacetime dimensions that connect all particle interactions in the Universe, no matter which set of dimensions they use to happen. And if we're talking about particles moving at the speed of light, that means the two interactions happen at the same moment and without a distance travelled in spacetime, indicating that spacetime is emergent from them and their interactions, and giving a hint that those particles have a special time dimension, the one that defines the order of interactions, and I have a strong feeling that this dimension is quantized and computable, since it's formed by a sequence of events. Konrad P Konrad P 1 year ago Hi Sean. Great job from you. I am a great admirer and seen many documentaries from you. I have an idea about nature of light a vacuum. So please how can i contact you to discuss it. It very interesting and if you consider it powerful enough it can be published why not. I have something to tell... imadetheuniverse4fun imadetheuniverse4fun 1 year ago If the wave function is one element of the hilbert space, I wonder what the other elements are? Gabriel Valeriolete Gabriel Valeriolete 1 year ago (edited) 10:00 - There was an observation (https://www.esa.int/Science_Exploration/Space_Science/Integral_challenges_physics_beyond_Einstein) that showed if there's some granularity in spacetime it can't be bigger than 10^-13 times the Plank length. So I don't think the Plank length is such a big deal. Kdawg_ Kdawg_ 2 years ago Can an observed particles position ever turn back into a wave function? Ron Ron 2 years ago (edited) Good morning Sean. Thanks for the vid. :-) Time for my mental exercise. This helps my understanding of this quite a lot. (but I have a long way to go). Valdagast Valdagast 2 years ago (edited) The wave-nature of electrons was observed in 1927-1932, so it's not that recent. Look up the Davisson-Germer experiment. The wave function was, the wave function is, and the wave function shall be. Blessed be the wave function. zicada zicada 2 years ago How far can one go relating this to computer science ? Could we say a function takes vectors as inputs and does operations on them ? TK TK 2 years ago Who would have thought that I would understand an infinite dimensional vector space or anything about what Dirac was up to. WOW khuti007 khuti007 2 years ago Finally...Thanks Doc What it IS, is a wave, what it LOOKS like is a particle. I have been looking at this for over a year. Now I understand that bit. Not much else, but that bit is clear now. Josh A Josh A 2 years ago Listening to this whilst looking at the 'trending' videos on YouTube. Having said that - - and I get the irony - - I'd love a Craig vs Carroll round 2. And thank you for offering this, your expertise, for free. J 1 dk6024 dk6024 2 years ago The Dirac delta function figures prominently in circuit analysis in electrical engineering. I think a similar technique is used in mechanical engineering, as well. David James Bolger David James Bolger 2 years ago (edited) Thank you once again Sean. Marian Music Marian Music 2 years ago @Sean Carroll I think that you could change the way mathematics is presented in schools, reorganizing it and making it easier to understand. This way more of us would understand it and our civilization would progress much faster. What is your opinion about the way mathematics is presented in schools? Would you try to do something at a great scale regarding that? Thanks for sharing your passion with us. Youtube is becoming a smarter and more enjoyable platform through the presence of people like you! DrPommels DrPommels 1 year ago I know you are doing your best to present the concepts without bias..... but your preference for many worlds/Everett cannot be suppressed! Scytale Scytale 1 year ago If the Universe is a wave function, with what "environment" does it entangle/interact/decoherence ??? Sam Harper Sam Harper 2 years ago What is the wave function made out of? Chalk, if you're writing it on a chalk board, and ink if you're writing it on paper. Extraterrestrial Intelligence Extraterrestrial Intelligence 1 year ago (edited) There is a universe in the multiverse where quantum mechanics never gets discovered because all experiments give the same results Johnny Rocketfingers Johnny Rocketfingers 2 years ago These videos are very appreciated thanks 1 James Stewart James Stewart 2 years ago As my undergrad QM lecturer said "I am certain that at the Planck length space becomes half a dozen colourful conesnails all named Steve... please feel free to prove me wrong." udita shukla udita shukla 1 year ago (edited) At 3:15 - "The elctron wavefunction wants to be smooth and spread-out". Why does the electron prefer a spread-out wave function? (We can only know that by solving the Schrodinger equation) 1 Michael Davis Michael Davis 2 years ago Here's an analogy that will get your readers thinking: a common garden tool that employs an entropic-drive. The leaf blower. Tony Belfast Tony Belfast 1 year ago Sean would you consider a smallest ideas in the universe series? things that are uninteresting and dumb and you explain why Mike D Mike D 1 year ago (edited) What happens at the Minimum and maximum of the wave function? Why does the wave function is waveving--more specifically . What tells the wave function not to wave anymore after it has reach the min/max, and just change back and forth from min to max then max and min ? Why does it have to wave? Archie Lundy Archie Lundy 2 years ago Edifying, particularly regarding Planck discreetness and the role or rather the lack of a role of consciousness in the double slit experiment. The Dirac stuff at the end I sense is fundamental but very hard to grasp. Thank you so much for doing these. Can't wait for the next one. Doug G Doug G 2 years ago All these fifty years of conscious brooding have brought me no nearer to the answer to the question, 'What are light quanta?' Nowadays every Tom, Dick and Harry thinks he knows it, but he is mistaken. (Albert Einstein, 1954). Does this statement still hold true? What did he mean? 1 Antonio Andre Antonio Andre 1 year ago In short, we can say that the iconic name Quantum Mechanics doesn't refer to a theory of quanta, but to one of smooth functions. So what's the point? The point is that the theory measurements do help going forward. So we really have to care about reality and not to overstate the fancy part of measurements. Prof. Eliot Jacobson Prof. Eliot Jacobson 2 years ago (edited) Good intro, enjoyed. But where does cohomology come in? And is qm an axiomatic theory? clavo clavo 2 years ago HMMMMM! Another Wonderful video! If sound waves travel linearly they are expressed as a wavy line with frequency and amplitude. But we know that the birds song is heard no mater where you are relative to the bird. Left, right, above, below or some combination. The sound propagates in concentric spheres and not in linear vectors. Using X, Y coordinates or even X, Y, Z coordinates is confusing because reality happens in concentric spheres and not concentric circles except when a human looks at them and only "sees" the 2 or 3 dimensional cross section of wave reality. Reality is in concentric sphere waves because all of human observable reality occurs due to electrons revolving around a nucleus that is traveling through space. We do not see the entire "sphere" of reality but only a cross section of the surface of it. Similar to the sine wave "signal" of an electric motor; but, more dynamic, because an electric motor actually comprises a linear reality as the armature has a definite length. I think. 1 Count Vlad Count Vlad 1 year ago As much as we are exploring the quantum world it is also exploring us. It is not like we have a box of toys or a sandbox to play with where we are the masters in control of it -- quite the converse. We are being monitored and measured, things are done on our behalf to see how we react. We have our formulas and measurements, but the quantum world has its own too -- measurement sizing up measurement. You think you are sizing up a bug in a sandbox but it is sizing you up too. How do I know this? It is logical that if the quantum world reacts to the observers then it observes as well. The bigger experiment includes our attempts at experimentation, we are part of the its bigger experiment. If you think aliens are out in space at the macro level... think again. michele somerhalder michele somerhalder 1 year ago Your explanation is the best!! Thank you. Kisses from Brazil. PifflePrattle PifflePrattle 2 years ago Back in the day the biggest idea in the universe was the understanding that banging a couple of pieces of rock together can provide a useful tool. Tool was one heck of an idea. I'm simply pointing out that maybe it wasn't really the biggest idea in the universe. Like QM or any other brilliant idea. IOW Don't be parochial . Just saying. Pavlos Papageorgiou Pavlos Papageorgiou 2 years ago (edited) 35:00 is it that helpful to say that Ψ is a vector in Hilbert space? I think you're saying there's an abstract domain, perhaps with infinite points, and Ψ maps that domain to the range of complex numbers. Also you can do linear operations on Ψ like add them or scale by a number. So far nothing new. Where it might get interesting is if you define what is the domain of Hilbert space (real spacetime, or something else?) and how vector operations produce things like persistent particles or localized scattering. I'm sure that'll get technical. So far I feel like I've been following an audio course for Japanese and it has been awesome. So now I can go to Japan and book hotel rooms and talk to shopkeepers or ask simple questions. But at some point the accessible audio course stops and you have to go to a real school or read grammar books or go and live in Japan if you want to become fluent. Still, getting this far on Sean's free public outreach is totally awesome! darkruby darkruby 2 years ago Newton and other pre quantum physicists continue to dislike this video. Science can not be stopped! 1 Michał Brzozowski Michał Brzozowski 2 years ago Has the double slit experiment with "monitoring" ever been done or is it only a thought experiment? Jim Russell Jim Russell 2 years ago Does the Planck length (or the Planck length x another constant) give the minimum gamma ray wavelength Bo Zo Bo Zo 2 years ago (edited) I don't like calling the essential wavy thing "the wave function." The wave function is a mathematical description, not the thing it describes. Call it quantum field waves. A Kumar A Kumar 2 years ago We are so lucky to get to watch these videos ♥ 13 Geoffrey Byers Geoffrey Byers 2 years ago "The wave function of the electron goes through both slits" - aha moment. I've never heard anyone say that exact language before. 10 Rusty Osgood Rusty Osgood 1 month ago Measuring things involves interacting with the "field" in some way. I don't think we can assume it is purely passive. We are measuring "wave functions" with tools that are orders of magnitude larger than the size of the effect. This is akin to measuring a red blood cell with a yard stick. We don't know what is going on on the scale of what is going on. I don't think it is fair to say that there is nothing "more fundamental" than a "wave function" when we don't really know what is going on here yet. Jacek Piterow Jacek Piterow 2 years ago If there is electrical field which influences magnetic field ten why there is no gravitational field which influences time field, then those could be influenced by other fields which manifest themselves to us as particles. I guess hence quantum fields theory. Also when measurement is done some energy should be used to trigger that but if one action gets opposite reaction then some energy goes also to the opposite side. I guess even smallest amount can collapse a particle function to make it appear at the coordinates where energy was excreted. Right? :) 1 Erik Dahlgren Erik Dahlgren 2 years ago When does the psi function no longer work? i.e when do we switch to Newtonian physics, and why do we do that? 1 Iain Mackenzie Iain Mackenzie 2 years ago Whatever the wave-function 'IS' and/or whatever reality it represents, is a mystery that, as you say, may be beyond our ability to perceive. But, one thing that emerges for me from your presentation is that it interacts (as a wavy, undefined thing) with the 'real' edges of the double slit and allows us to experience its behaviour. For me , this offers a little window into its true 'nature'... (Not that I am trying to avoid getting to know Hilbert space entirely :) Jaibir Jaibir 1 year ago Dr Carroll, the 4th system you discribed in double slit experiment i.e with monitoring, is this experiment performed in lab?? Or it is just a thought experiment. Dexerino Dexerino 2 years ago I think I will watch this regularly now :) Shalkka Shalkka 2 years ago Surely when the electron is approaching the barrier if the barrier is bumped the electron stops and if the barrier is not bumbed it does not stop. In that sense the electron is going to entangle with the barrier. I understood that part of the reason to say "no entanglements" would be that any "eye" that strongly correlates with which slit was used will trigger the particle-like outcome. But if you have a "detector" which beeps if both or one of the slits were used that would be in the same state regardless of which slit was used and would thus result in the wave-like outcome? Bernard Whipps Bernard Whipps 1 year ago I stayed to the end even if my brain didn’t. What’s waving again? 9 C. Zorba C. Zorba 9 months ago "In one of Aesop's fables, a fox sees a juicy bunch of grapes and leaps to reach it, but can't quite jump high enough. In frustration, he declares that the grapes were probably sour, and he never really wanted them. The fox represents "physicists" and the grapes are "understanding quantum mechanics" - source Something Deeply Hidden, Sean Carroll; It's very hard to come and prove something new, we could ask Galileo, Giordano Bruno ... even Einstein how it was hard. You will succeed, you are the new Galileo's. Thank you Dr. Carroll for sharing your know-how, your intelligence, time ... I am very grateful for learning from you. : Antypas : Antypas 2 years ago (edited) Oh time went fast, now I have to face reality. 3 Dustin King Dustin King 2 years ago The Dirac math made my brain a little wavy. 20 Nathanial Blower Nathanial Blower 2 years ago If Wittgenstein is going to stop you from ‘asking’ “What’s waving?”, why doesn’t he stop you from ‘asking’ any ‘question’ whose ‘answer’ is “...because there are many possible worlds, that’s why...”? spheresong spheresong 1 year ago What is waving? The maths are waving! It feels uncomfortably like circling back to the idea of aether. hokiturmix hokiturmix 1 year ago (edited) I like actualized leos videos about spirituality in a non religious way. He has videos about quantum mechanics. He quoted you in there too. I really would like to know what your current opinion about this stuff. The Allan Wallace video was clear. You may changed ever since. Jayarava Attwood Jayarava Attwood 1 year ago How is it possible to talk about "the wave function of the electron" when it is in an atom? Surely, this is a spherical cow. The electron and the proton in the H atom interact *constantly*. Are they not entangled? Axis Axis 2 years ago Started listening: "...hoping that this video will be short and sweet". Looking at the length: 46.05. Great, let's continue listening! ;) OEDIP ZX10R OEDIP ZX10R 2 years ago i guess Wittgenstein referred to metaphysics or speculative philosophy... generally everything that is not logic, as he know logic from Frege. science and mathematics was part of what he loved because it's formal and univocal Roy de Visser Roy de Visser 2 years ago Everything is a wave & everything is a partical, do I understand correctly a partical is the result of a colasped wave. I assume that the partical is the lowest energy point of the wave function and the highest energy is the largest wave. I bet the answer is the partical and the wave are entangaled. Andrew C. Mumm Andrew C. Mumm 1 year ago I wonder what Sean thinks of Stephen Wolfram's newest work... Nathan Van Pelt Nathan Van Pelt 2 years ago i obviously can't understand what the wave function is, maybe we didnt evolve to make sence of it. what is that called? the belief that understanding reality is impossible for humans? anyway, the idea that the wave function IS reality is unfathomably beautiful to me. make me cry beautiful. David James Bolger David James Bolger 2 years ago (edited) Quantum mechanics requires a cheat. That’s like a hint at something deep. That in some way we will never get the GUT. But we will inch forward closer and closer to the perfect answer and before we know it. Our quest to answer a Question that’s unanswerable has caused us to make amazing things exist that didn’t before. Like our curiosity was used to trick us into making a more interesting world. Doug Kuykendoll Doug Kuykendoll 1 year ago Why do we pose that the observables such as electrons or photons are acting like a wave but then a particle with the collapse of a wave function instead of posin thomassaurus 1 year ago