The Biggest Ideas in the Universe | 8. Entanglement
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- Опубліковано 18 тра 2024
- 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 #8, "Entanglement." I talk about what entanglement means, how it showed up in classic work by Einstein, Schrödinger, and Bell, and the crucial role it plays in competing formulations of the foundations of quantum theory, including Many-Worlds and others.
My web page: www.preposterousuniverse.com/
My UA-cam channel: / seancarroll
Mindscape podcast: www.preposterousuniverse.com/p...
The Biggest Ideas playlist: • The Biggest Ideas in t...
Blog posts for the series: www.preposterousuniverse.com/b...
#science #physics #ideas #universe #learning #cosmology #philosophy #quantum #entanglement - Наука та технологія
Physics students of the 60s had the Feynman Lectures in print form. We have a Sean Carroll UA-cam playlist. What a time to be alive.
@Astute Cingulus : Quite right, but GR can be extrapolated to the Planck scale. It's just that doing so we find it disagrees with QM. This I believe is actually Sean's point, or one of them.
Amen.
Jeremy Roy Your right. I bet they were loving the print lectures. Hahah
In the 60s they had Feynman lectures on cine film, in person, and had tutorials with him directly, plus drinking with him I bet
we are living in the McDonalidization of knowledge. Type a few words into google on a device the size of your hand and nearly all knowledge of humanity is literally at your fingertips. Now we just need people to enjoy it as much as they do McDonald's
Hey, sorry for the mixup with the previous version of this video! Somehow I uploaded the wrong version, I had to delete it. This one should be better in both audio and video quality.
I love listening to you explain about things I never and always knew I as curious about
Less tearducts, more physics, great!
Sean Carroll let us know when that textbook is out!!!! Can’t wait!!!!!!
All good, thanks
All of these videos have been amazing thank you so much for your hard work.
I am artist with very little understanding of physics. I have been so interested in my whole life, and five or so years ago, gave up on my attempt to understand or appreciate the subjects that you've been teaching in this series. This is exactly what I've been hoping for for so damn long! I have the drive to learn more about this stuff again. Every episode starts with me doubting myself, that I'm too stupid to get it, and ends with my mind being blown, and feeling like I have a new outlook on my ability to understand... well, anything.
You are correct. You have very little understanding of physics. :-)
quickly becoming my favourite series on UA-cam.
Hope it continues after the lockdown even if he does them less frequently.
@Astute Cingulus I miss carolin crawford/Ian Morison both fantastic speakers.
Ditto
@@yishaimendelsohn620 too For for the day that we wayHome From At f get rest f, to get d74^3
How lucky we are to have people like Dr. Carroll willing to share their knowledge of physics with us! I love it.
A 1:20:29 long video on solely entanglement. This is unique
Entanglement, yes! Been trying to get my head around it for awhile now, every time I think I have it there's more around the corner, angular momentum was an entire rabbit-hole on its own. Thank you for sharing your knowledge Sean, your videos are my favourite for explanations of complex ideas.
this may be off, but i simply think of it as particles sharing information aka energy and the more they share the more entangled that they become. to the point you get stuff like us.
any time particles interact in the universe and share information i tend to think entaglement is all over all the time and not wierd at all.
i look at information as the key and the type of information secondary.
but i could be and probably am way the hell off.
Complex ideas?? Just being plugged in and realizing nothing is impossible. Upward and onwards All day everyday
I would read Nobel Prize winning John Bell’s book, “Speakable and Unspeakable in Quantum Mechanics.” To really understand his Nobel Prize winning theory that was confirmed experimentally, Bell’s Theorem.
Love that every so often Sean's hand slips in and out of "phase spacetime"
when he becomes more demonstratively excited! Always thought he might
actually be a many worlds traveler. Confirmation; seeing is believing!
Favorite video in the series thus far! Thanks Dr C.
The best explanation of entanglement I've ever heard.
Wooo! Been refreshing the page all day waiting for this :)
Or you can click the bell icon.....
You’re the man Sean. Thank you for doing these.
You’re really good at making the equations seem less scary, and explaining the reason behind the numbers.
I can't wait for the upcoming class/episode! Mr. Carroll is the best "teacher" (I've watched quite a few online) in QM I've come across. Really hope he continues to produce classes (and alike) about QM for the unforeseeable future!
This was my favorite of this series so far, and they're all great. Brian Greene also provides a really good explanation of Bell's Theorem in "The Fabric of the Cosmos."
Wow! - Entanglement in a purple hot tub! Isolation doesn't get much better than this!!
Thank you Sean, for the highlight of my week :)
Thanks for posting, surprisingly easy to follow. 👍
These talks are absolutely phenomenal. Prof. Carroll is an excellent educator, who is able to convey very difficult topics in an easy, understandable manner, making them reachable for broad audience without scientific training. Thank you, prof. Carroll!
Thank you so much Mr. Carroll for these series of videos. It's my end of day everyday and I've been learning a lot about these subjects. More than the lectures and I've seen a lot of them. Thank you so much!
Thanks for the podcasts and videos. I appreciate you.
Thank you, Professor Carroll.
OH MY LORD. I never thought I would understand entanglement. Sean you are AMAZING.
Very interesting stuff explained in a way everyone can understand it. Thanks, Sean.
Amazing how fast you can make these videos -- I love the quarantine :)
best podcast ever. i had to rewind a few times to get things again. you're a great science communicator, thank you so much.
I think in episode two of this series ‘Carroll’s Cat’ certainly was not sleeping.
Good video.
Thank you so much Sean!
Love this topic. Thanks Sean
Fantastic body of work with these videos. Well done. Keep it up.
This is so enjoyable. Great teaching. Thank you for doing this.
This is amazing thank you.
This is probably the best talk so far of a great series. I finally understand (a little) "Many Worlds,"
which had always seemed ridiculous to me. It was the orthogonal axes that did it.
I so enjoy these lectures!
With the entanglement episode, you made me think of the story about the blind men and the elephant. Each touching a different part of the animal and from that having an opinion about the nature of the creature. It is hard to state what the entirety of something is (and exciting!) - not knowing the whole creature…
Thank you so much!
Henry B.
Thank you for taking the time to do these videos they are great. You are respectful and dont assume you are talking to a room full of kids thanks for all the details and real explanantion this is a very valuable video series.
Sean, very smooth talk, I really like it.
You used two particles/waves collision as an example for entanglement. It makes sense to me but this is the first time I hear that kind of use case in entanglement.
The two particles collision case can be seen as following Newton’s 3rd law of action vs reaction, although this is QM which makes Newton’s law dubious.
A more interesting case is the action over distance in gravitational force. Has anybody tried to apply the entanglement idea to explain action over distance in gravitational force?
It seems there are different types of entanglement. The spin-based entanglement is one type, the two particles/waves collision you mentioned here is another and the action over distance in gravitational force is yet another.
These videos are very much appreciated thank you so much.
I'm glad that I live in a universe that has people like Sean Carroll. I never get tired of reading his stuff.
Biggest entanglement in your lockdown hair X I so enjoy your stuff. Thank you.
I have heard about entanglement many times. But this was super duper explanation Professor!
Finally it does not seem as a pure magic for me anymore.
Thank you for this.
Another great video, Professor Carroll!
Also, I have read the professor’s latest book, Something Deeply Hidden, and I highly recommend it to anyone who really enjoys this video and wants to learn more about the foundations of QM.
Learn linear algebra if you want to actually get the foundations of QM
Another good reading: Sean's CV. It's impressive. www.preposterousuniverse.com/cv/
Please share Ur insight
1.whats Ur thought on experiment that monkey is sit on type writer and one of possible worlds it creates Shakespeare play ,or quantum immortality,these are the weird implications
What's Ur thought folks please share
tripp I look that in my first year of college in 1981! I have not used real math graduation
This playlist is gold
Thank you! for making more accessible, these highly abstract and technical concepts to those of us who love physics and...and assuming we're not stupid! SC a fantastic human being, thank you sir for sharing!
If you want to see a great man with no pretentious ego, Sean Carroll is one such !!!
The fact that im listening to many quantum physic explaination doccument video or podcast or conference show how small we know about it because almost if i click anywhere in the video after 5 minutes we always comeback to talk about the particules react diferently in the observer point of view and in real life situation when the influence of the observeris not there or because the observer cannot see because its something to see its something that behave and change state. if find it really interresting to listen because i dont dont know if its the same thing as someone who is learning a language and by listening a lot of it you are able to figuere it out more and more in your head. Now that its been almost 5 years where i listen almost everything i can find on the subject i can more and more represent it in my head . Thanks for doing your job that way thats a great way you are a great speaker too .
47:00 A interesting observation I had one day. I was entering the mall one day and some doors were automatic some were of the manual variation. You could see by the wear in the ground how much each was used. It reminded me of the double slit experiment. But it was people and shopping destinations.
Really nice lecture, thank you very very much sean :)
OMG! From the 1st lesson about basic calculus, Sean reached the point of negotiating the deepest questions of the present. I'm afraid this means that gradually this wonderful series is coming to an end... :( Anyway thank you so much Sean...
Your version of Schroedinger's cat doesn't work because the cat is likely to be asleep either way
Thanks for these videos. Wish I could buy them.
Fun times to be so entangled with UA-cam.
Sean, I downloaded the "Universe Splitter" app that you mentioned In your book, "Something Deeply Hidden," which I am still enjoying reading. I asked it if I should "Study physics" or "Waste my time." It told me to waste my time. A few minutes later, I asked the same question again. It told me to "Study physics." I now feel myself in a superposition between studying physics and wasting my time.
Dean Batha No. You have split into two worlds. In one world Dean studies physics, in the other world Dean wastes his time. Since you are watching this videos the Dean I'm responding to now is studying physics. In the other world, Dean never bothered to post this comment on UA-cam and is wasting his time. LOLOLOL. Dean was in a superposition BEFORE you used the "Universe Splitter" app. That in a nutshell is many worlds.
This has finally answered my questions on entanglement, I love popular science descriptions, however at times, you just need to run through the fundamentals.
Thank you for all of your lectures, you make complex subjects more understandable, (although I can't follow the math). I wish I had a instructor or they told us this stuff when I was a kid I might have gone into Quantum Mechanics.
Amazingly bright
Thanks, Sean!
You have quite the visual style, Dr. Carroll. It reminds me of '80s era VCR tapes for some reason. Love all your content.
i like the intro with his floating head in space
it helped me so much to read his book first and then watch these videos :)
I like this format with the virtual blackboard
I had some sadness in my life related to the covad-19 thing. The only way I could remove my self from the sadness was to watch this video (I read your latest book). Your talk took me to another place where I had to think really hard to follow along. Not that I understand it all, but it is so very helpful. Thank you.
I hear your pain. Take a hug? Keep plugging…
@@brucegoodwin634 Thank you so much Bruce. Yea, I will take that hug and back at 'ya. I am so very pleased that Dr. Carroll is doing this series. It expands my mind. What a wonderful thing for him to do. It is like the best collage teacher you ever had.
This is really good informative stuff Prof Carroll. I really want to thank you for making all these videos - this one in particular. The nature of entanglement and quantum decoherence leaves me wondering if it will be possible to actually build a useful quantum computer - or if decoherence will present insurmountable technical problems
I barely understand algebra, but I still listen to these beginning to end with complete interest. thanks sean
k
I am a simple man. I see Sean Carroll channel. I subscribe.
Great series
This raises a question in my mind. You have two balls, a red one and a blue one. Pick one at random, don't look at it, and send it to Pluto. Then look at the one you kept. If it is red, you know the other one on Pluto is blue. There's nothing spooky about that. No FTL travel required. Please explain how what you are saying is different.
purple background is awesome... color works for ya...!!!!
This was so good, thank you Sean. Additionally, I really enjoyed Mindscape episodes with Adam Becker and your solo episode about this very topic, I really liked the idea how space is basically and emergent property - two things being close is defined as being able to entangle with each other. I've bought myself a copy, but haven't got the chance to read it yet. I have two questions about the video:
1) Decoherence. Why don't atoms destabilize? We saw that electron fired into a cloud chamber is behaving pretty classically and not like a blob of uncertainty. You explain it like it's getting entangled with everything around. I like that. But how come the electrons in atoms don't de-cohere when every other atom from vicinity is bouncing into them? As we've seen in the previous lecture, the work of Planck-Bohr-de Broglie-Schrödinger explained the electron in an atom needs to be quantum and classical particle just doesn't work.
2) There're projects of 'quantum reconstruction.' Mathematically minded people are trying to rediscover quantum mechanics from simple foundations and derive it mathematically. This is because some people are uneasy because Planck, Heisenberg, Schrödinger and others basically just guessed it. Some of these are based on quantum thermodynamics or quantum information theory. Are these approaches compatible with many worlds?
Very good material in Physics.
Live Forever and Prosper, Sean Carroll.
Live Forever Young and Prosper, Sean Carroll.
Thank you Prof. Sean Carroll for this passionate thorough and science loving presentation about the subject of QE and not only and specially for its interpretation in the the many worlds theory context. I kept and cherished specially your phrase that decoherence is the entanglement of the quantum particle with the "environment". QE, superposition and all the "quantum weirdness" could be resolved by simply examining that what is very obvious possibility for me and was all the time in front of our nose, that vacuum 3D Cartesian space is a medium in an underlying intrinsic superluminal energy state and that our matter Universe is actually the phase transition of this superluminous medium to luminous or lower energy states. In this context, all "spooky actions at a distance" in our spacetime domain and frame of reference, would appear instantaneous as actions would propagate instantly as it would appear to us and timeless intrinsically in this underlying vacuum space superluminous energy state connecting all actions and phenomena like a gel. Einstein said that there can be no superluminous energy state but he was referring to our spacetime 3D reality domain. That necessarily does not mean that there can not be an underlying higher energy state to our Universe which is completely invisible to us... well not completely, QE is one hint.
Let a thousand flowers 🌺 bloom across the multiverse of speculative ideas.
The real “Mr. Universe”! Just awesome! Thank you for this video (too) Mr. Carroll! Me: never stop learning just sometimes “sleep a bit longer”! 😉
Dang! I thought I understood Sean's answer to the question in the last video of "What is waving in the wave function?" until this video came and shattered that perception. I thought he was talking about spacetime, but now I see he wasn't. It goes deeper than that. Incredibly fascinating stuff, but I am continually cursing the limits of my intellect. I know I wont' ever fully comprehend these concepts, but the challenge is great fun. Keep 'em coming, Sean.
Thank you Professor
Entanglement: one of those words whose meaning changes as the year passes. Like iconic.
I am old enough to remember when it involved splitting a quantum particle in two, consigning each of the halves to opposite sides of the universe, then tapping one to make the other jump simultaneously. The logistics of such an experiment were always rather fascinating, I thought.
But then I can remember when an icon was a small painting on wood of a Christian subject created in the Byzantine era of the Roman Empire in Constantinople
Ah me, those were the days
Very nice lecture.
What if there's a hidden dimension where entangled particles are still adjacent even when they are far apart in 3D space?
The book you mentioned, "What is Real", is an amazing read that covers the history of QM interpretations and the measurement problem. It's a must read for anyone fascinated about the story of Quantum Mechanics and all of the controversy surrounding it.
Hi Sean, what an amazing series! When I think about the reality through quantum physics eyes, and wonder how nature works, I was compelled by Many Worlds from the begining, though not sure about it, because I felt it is somehow wastefull, by splitting the universe with each interaction. Thanks to you, and your series, I have gained knowledge, in understanding QM as well as Many Worlds in the way I see it through different perspective now, and I like it even better.
Always appreciate your lectures and appearances (WSF).
Question about topic at hand. Decoherence seems to me like pretty strait concept and I wonder why it had appeared so long after concieving Quantum theory, why Shrodinger and others haven't thought about it?
Regards to you, Sir and your very familiar cat in our branch of the wave function of our Universe bouble.
Feynman, Susskind, Carroll ... three great explainers, but with very different styles and emphases. I can’t say which is more influential, but I am so glad that Sean has decided that this is a good use of his time. For me, these talks are very accessible.
Susskind, the cookies-munster?
The perfect duet - Sean Carroll with The Biggest Ideas and Brian Greene with Your daily equation. I could hear and learn from them all day long.
i sometimes get those 2 guys mixed up
Excellent!
If I was studying quantum mechanics at uni, I would be thrilled to have these "big picture" videos
Sean, thanks for putting out these amazing lectures. You are an incredible teacher!
I honestly feel that these videos have much more utility than all the nonsensical and pseudo-sophisticated "Theory of Everything" garbage being propagated by certain individuals (e.g. Weinstein and Wolfram) who are not even directly involved with the established physics community.
Kudos to your efforts! I'll be looking for your undergrad QM textbook when it comes out.
Is he actually working on an undergrad QM textbook? Asking because I have no doubt that would be an amazingly lucid intro to a difficult subject. Maybe he can answer on his next Q&A!
Aaaaand lo and behold, 3 minutes in he answers my question. Looking forward to it.
I think what Wolfram and Weinstein are doing is still massively important to the physics community, but their efforts are *very* niche in application. We are at a point where string theory isn't able to be confirmed experimentally (yet) so having some other theories is definitely beneficial in case string theory doesn't pan out. But those new theories really aren't relevant yet either, especially not to those without a career in physics that can make sense of their arguments and mathematics. An overabundance of ideas is never a problem in science, but if understanding Quantum theories is just a hobby for you, it's worth cutting out most of the noise until scientists can reach a new consensus (or at least start moving towards one).
@@nihlify True, but these vids are based in what we know of the universe and our theories of the implications of this knowledge. Weinstein is talking about rulers and protractors in a way that I find to be completely incoherent. His "hidden knowledge" that he's been afraid to reveal for the trauma it might bring us. OK fine. But perhaps he could discuss with an educated peer who has the knowledge to at least work through what he's trying to say and challenge him in the foundational ideas.
@@dustinirwin1 Weinstien is talking nonsense clearly. A decent analogy would be Jay-z and Nas (just because he wear a kufi doesn't mean that he bright.) He uses big words and obfuscates the point. He is the type of person who seems smart to dumb people.
I really appreciate how neutral you are with your preferred theory while being objective in fairly expressing the alternatives. That said, many worlds feels an awful lot like string theory to me, though instead of making up n dimensions, we make up n worlds. Something about it feels off to me. But that's just a suspicion!
I suggest you watch the many worlds part of the video again. Sean Carrol is trying to stress really hard that the many world's theory does not 'predict/assume' the existence of other worlds/universes. The theory just states two postulates which IMO are unequivocally true. The 'other worlds' come about when you try and attach meaning to the theory, ie how you INTERPRET the theory. Ofc the other branches of the wavefunction cannot just be ignored, after all they must be there for some reason, but you shouldn't be dismissing the theory just because it's hard to interpret.
Wow. Super cool background 👍👌👌👍
It's an honor to hear you gentleman.
This is what went through my head following your interesting lecture: Isn't the Schrödinger cat problematic just a consequence of our thinking in categories, which we turn in a slight of hand into discrete states of nature? It reminds very much of the cow as a point mass. I have never seen a cat that is in the state of being asleep, or in the state of hunting mice (but I have seen a cat sleeping and possibly dreaming about hunting mice). This whole idea of physical state is great, especially when you can assess it quantitatively and make predictions about it, but for almost everything else of greater complexity it remains just an empty abstraction. How many possible states has a large molecule made up of 10,000 atoms? How many states has your brain with all its10^11 neurons, each one of which being as complex as a little universe? And, since you mention of course the Schrödinger equation of which that monstrosity is supposed to be a solution, one might challenge you to write down the Hamiltonian for that :-)
The "solution" of integrating the cat, the entire apparatus, and the observer (with brain and guts and laptop) into one grand wave function seems attractive on first glance, but it is still an unbelievably great leap of faith to generalize from an entangled state of a few atoms (or even a million atoms) to "the Psi function of the universe". Some religious person might ask - does it include God? How far have we really moved away from trying to answer the question how many angels fit on a needle tip?
A few questions: What relation does many worlds have to the arrow of time? Can wave functions branch "backward" in time? If not, why is the wave function time asymmetric? Does the present moment have multiple possible pasts? Is entropy related to many worlds in any way? Could many worlds be emergent from a more fundamental law of the universe, such as for example, "all things that can exist do" and the branching then happens when different logically consistent possible realities can no longer logically exist together anymore? Could the laws of physics as we observe them be the original branches of the universe? Could other branches have other laws of physics or different values for universal constants?
Also, thanks so much for making these videos! I hope you truly understand and internalize the impact they have on the world and especially to your viewers.
As for the entropy and the arrow of time, QM has the exact same princple, the worlds decohere, and there are many more decohered states, and so statistically you move to a state of 'lower entropy' but there is a tiny tiny change just as there is with entropy that they will 'recohere' but it's so insignificant that you don't need to worry about it
I think that the entropy question with regard to the Everettian interpretation was briefly mentioned in Professor Carroll’s Google lecture but I wonder if he could expand on it here in this “The Biggest Ideas” series?
1:10:58 "many worlds is plug and play ... for those of us who are interested in pushing the laws of physics beyond what we currently know into more speculative realms ... hidden variables are not nearly as compelling as many worlds."
I seem to remember that Feynman stressed this point quite a bit. So can you elaborate a little bit and make some predictions to help better explain this point? The next big breakthrough in QM and QFT that incorporates gravity or solves some big problem, can you assign probabilities to what the authors of that paper are likely to believe as their preferred interpretation of Quantum Mechanics?
Probability that the author is a believer in Everettian interpretations of QM?
Probability that the author is a believer in Bohmian Mechanic interpretations of QM?
Spontaneous Collapse?
Cubism?
Some variant of the Copenhagen interpretation?
This is the best ‘Many World Interpretation’ that I have heard! Thank you so much! I still don’t believe this is how it works. I personally like the ‘Wave Collapsing’ theory better! I’ll wait to see how it turns out!
The wave collapse almost seems more magical and hence probably wrong to me. It gives too much to consciousness and woo talk. Many world's seems magically unreal in a different way but entanglement makes it seem more intuitive
Sean is making lockdown bearable.
I just discovered this series of videos, and I'm like a vegan in a tofu store. Any update on the undergrad quantum physics textbook mention at 1:38? I searched on Amazon and at preposterousuniverse and didn't find anything. Thanks so much for this great series!
Best way to sleep every night. Not boring! Relaxing!
Sean, thank you for making this complicated topic so easy to understand conceptually. Even though the maths is above my head.
I do have a question about the future of Quantum Mechanics. I would like to know "what's next" in a few areas, namely:
- What's next if something like QBism is experimentally proven or many worlds falsified
- Can you imagine any other new interpretations that have no theories, just speculative as to what the bounds are of what it could all mean
- what are practical applications of understanding this more or is that unimaginable until it is understood more?
And what is day to day life like as a physicist in lunch room talk on these topics? e.g. I'm a programmer and we get into debates about languages, libraries, programming techniques etc. Do you and your colleagues discuss it much or is this a taboo topic?
fantastic.
Hello, Sean! Watching your videos has actually given me a pretty good picture of the current state of affairs, and I appreciate this immensely, being a total layman in physics. I have this question: if the Wave function is not only a tool to make predictions, but is instead something real, how do you even start studying it? Who sets its values? I'm a bit lost, I can't really formulate my question right, but the reality or unreality of the wave function stops me from even thinking about it. Help!
Thanks a lot for the videos. I have some Qs for the Q&A: 1) Is there any kind of "profound" connection between each of the conservation laws and each pair of conjugate variables in Heisenberg's unc. principle(s)? Is there a one-to-one relation, or one can arise from the other? 2) Isn't the dismissal of "super-determinism" at odds with the acceptance of the Anthropic principle (which I'm also fond of but...)? If I understand well, it's not about the experiments being able to be imagined, but whether some outcomes will ever happen or not. Accepting the Anthropic principle implies that many of them won't, because those are not the outcomes that would allow us to be here to measure them. And that's very similar to the idea of "super-determinism". 3) Could you comment a bit more on how non-locality fits in the MW interpretation? The idea of decoherence being triggered by the environment seems somewhat local to me (or at least it appears; maybe it's just the word). Does decoherence/branching happen instantaneously everywhere or does it propagate at c? Also, can be particles entangled in any property that is not part of any of the Heisenberg unc. principle(s)? (or conservation laws?). Thanks again!
We need to get him to 100k!!
13:00 Sean gives a solid definition of entanglement after motivating it the previous 13 mins. I have a feeling this episode is going to be crucial for a lot of moving parts.
I think now in part I am able to articulate some thoughts around the (DSE) double split experiment, which is supposed to highlight the wave-ness of stuff, which collapses into particle-ness when we detect/observe it. We also have this idea and assumption of “a (physical) system”, which might come into play as confusing.
So we have some electrons that are being fired out of a gun, through two slits as wave-like, and collapse as they (singular) hit the detector. My sense, which may be wrong, is that the wave collapses as we observe it, which means we are detecting it, which really means it is being entangled with the physical system of the detector. But how does this wave like form leave the gun, which is also a physical system, go through the slits, the walls of which are physical systems, and then hit the detector, a physical system, but only get entangled (collapsed) at the last step? If we are all in the same universe, kind of by definition a universe entangled with itself, how could we ever see directly or indirectly, wave like properties?
Three comments:
1. Thanks for another fantastic discussion. I now feel much better about “Entanglement.” (Meaning I will no longer fall asleep wondering about it.)
2. I agree 100% with Jeremy Roy's comment below.
3. I certainly did not know it, but it now looks like I am a “fan of” some Alternative Theorem. The cat still gets me but I’ll wait for your discussion on “measurement” before firmly taking a position.