How Quantum Mechanics produces REALITY & perhaps ARROW of TIME | wave collapse & Decoherence
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- čas přidán 22. 05. 2024
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Citations:
Yale research on recording wave collapse, Minev et al: t.ly/cX9v
Bouchard et al paper on observing recoherence: t.ly/rOqb
Quantum mechanics link to time, Smolin et al: t.ly/2Psj
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Chapters:
0:00 - What's the problem?
1:08 - Quantum indeterminism
2:42 - What is superposition?
3:50 - How do we know this is reality?
5:03 - Switch from quantum to classical
6:06 - Quantum decoherence explained
8:52 - Is decoherence really irreversible?
11:26 - Is there a point of no return?
12:18 - How does QM determine time
Summary:
How does the indeterminate world of quantum mechanics, where the future isn’t fixed, become the classical predictable real world we experience? Quantum researchers argue about it even today. It's really all about time, and the boundary between the past and future.
Quantum mechanics insist that the spin of particle has neither one direction or the other until we look. The very act of looking forces the universe to make a choice.
All the variables that characterize the properties of an elementary particles, such as its position and momentum, are encoded in a mathematical expression called a wave function. It is just a sum of the states that the particle could be found in. This is called a superposition.
By itself, the wave function doesn’t have any intuitive meaning. But the square of the wave function gives us the probability of finding that quantum object in any particular place. Prior to measurement, quantum mechanics doesn’t really tell us anything about a particle. We know this is true because particles interfere with each other prior to measurement as in the double slit experiment.
In our macro world, we never see this superposition. So quantum physicists have to add in this transition from quantum to classical step by hand, as something extra to quantum mechanics, ThisIt is often called the “collapse” of the wave function, and was first introduced by the Hungarian mathematical physicist John von Neumann.
A better description of this is decoherence. This is how it works: The quantum state of a particle becomes mixed up - or entangled - with the states of the atoms in the environment. If the particle is in a superposition, this superposition then spreads to the atoms it interacts with. The come these entangled particles interact with, the farther this entanglement spreads until it spreads all across the universe. This leads to decoherence, because not the original particle becomes unrecognizable.
But the problem with decoherence is that in theory there is no end tot he entanglement or spreading of this quantumness. So in principle the superposed state of the original particle could be reconstituted if we could keep track of all the entanglement of all the particles.
But this would be like reversing time. Experiments in “recoherence” has been done however. This would mean undoing the measurement, and erasing any information we gained about it.
So here’s the question: Is there ever a point where the measurement process switches from being fully reversible in principle by this sort of recoherence, and becomes irreversible? Is there a point of no return?
Quantum experts don’t agree about this. As long as the process is reversible, it’s still quantum. It’s only when it becomes irreversible that it becomes classical - and it’s only then that we can truly say “what happened” - when reality becomes real.
Physicist Lee Smolin has suggested that this is in fact what distinguishes the past from the present. The past is classical. The present is quantum. What separates them is whether they are reversible or not, whether they have become known or not. Quantum mechanics may link knowledge, information, and time.
According to Smolin, It’s the change from a quantum, indefinite present to a classical, definite past that defines the very arrow of time itself, pointing it always in the forwardin one direction as the quantum present constantly churns out a classical past.
The past goes away. It is already known. But the future is all possibility. We can never go back - we can’t change the past. In fact, the past no longer really exists at all. “Once something is definite”, says Smolin, “its job is done and it is gone.”
#decoherence
#quantummechanics
But what happens to all those futures that aren’t selected by the decohering present? Where do those alternative possible futures go? Do they pop up in an alternative universe? Or is there just one reality?
Outro Artist of the week: Sander Kalmeijer, performing title "Gold Medal" - Věda a technologie
Here is a follow up video explaining ENTANGLEMENT more fully: czcams.com/video/unb_yoj1Usk/video.html Also, here is more detail on what a wave function "collapse" probably is:
The whole process of “wave function collapse” proposed by von Neumann effectively introduced, in an ad hoc way - through measurement - a way to make the quantum evolution of a system become irreversible, i.e., to draw a line between quantum and classical. Does this really happen? Probably not.
Decoherence is the modern approach to explain how quantum systems transition to classical. It results when a quantum system entangles with its environment. When this happens, the components of the wave function of our original system are decoupled from a coherent system, and they acquire phases from their immediate surroundings.
This entanglement spreads not only to the local environment of the quantum system, but everywhere in the universe. Strictly speaking, there is no mechanism in quantum mechanics that “breaks” the entanglement. It keeps spreading. The coherence of our original system becomes unrecognizable.
This is analogous to dropping a blob of ink into the ocean. The drop is never formally lost because in principle you could bring all the particles of the ink back together again. In practice that is not possible. Similarly, the original superposition of our initial quantum system, in principle, could be recovered if we could keep track of all the particles and their effect on the phase changes of our original system. But this quickly becomes impossible to do.
There is no wave function collapse, but at some point, the original system becomes irretrievable, so there appears to be an "apparent" wave function collapse. Exactly when this happens is what Lee Smolin believes demarcates the present from the past. For details on Smolin's paper, see link in the description.
absolutely wonderful. I've never been able to understand this concept in such eloquent manner. thankyou.
Arvin this video is fascinating.
One of the best you have made so far.
I am a fan.
So to the best of our understanding everything came from a single point in space and time that we have labeled the Big Bang. I believe it was an enormous burst of energy that produced all the matter and antimatter that the Universe consists of. This is currently the most accepted theory I believe, right?
So if what I described before is in reality what happened at the exact moment of the Big Bang, the universes very beginning as far back as we can currently imagine wouldn't this mean that everything in the Universe was or still is entangled?
What happens to all the future possibilities that seem to be unchosen ? Who says anything happens to them ? Isn't there theories regarding the future influencing the present/past ? Why can all possibilities exist simultaneously ? In each "present" where we exist maybe there are multiple pasts that could have brought us there but we recall just one plausible past. Similarly with multiple possible futures but we erroneously expect only one to exist. Each version of us feels we are the only one, in the only present, but are unaware and unable to detect another to prove otherwise. Are you really the same you now who started reading/is starting to read, this post ?
@@WideCuriosity the best question , to the points , i love it
I really like how he talks about papers that are published very recently. This shows he studies so much about the things he create videos about.
Yes. Late April.
@@makeracistsafraidagain can I ask you where did you get that information? Thanks in advance if you reply 👍
@@jorgeolivar3712 in the description just under the video. enjoy.
I just like it when he talks, he seems like a bloke I'd like to debate with over a beer
He's good at explaining concepts but it's obvious he has no rigorous training in physics or astrophysics.
This is the most intuitive explanation of quantum mechanics available anywhere. Period. On behalf of the entire layman science enthusiast community, thank you, Arvin. 😌
Wow. Much appreciated.
@@ArvinAsh You are the best
Arvin, I just wanted to tell you that, not only is your content just good, but you are by far the best I have encountered at explaining physics. As an older engineering student who's mind isn't as flexible as it was when I was a teenager/early 20's, I can't thank you enough.
Arvin Ash, you explain very complicated phenomena in a very simple way that a 72 year old man like me can even grasp. Thanks and keep going.
Real captions/subtitles/text ! And in 9 languages!!! That's solidarity and professionalism hand-in-hand. You simply cannot know how much it's appreciated!
Glad you find it helpful.
Well, I still miss the Hungarian subtitles (even though Hungarian physicists were mentioned! ;P )
@@ArvinAsh -2 people, A and B.
-1 coin.
- They flip the coin taking turns, A starts. - Who first gets "heads" wins. Stopping the game.
Suppose a coin with a weight on the "heads" side causing it to always land on the "tails" side.
How likely is A to win?
Answer - 0, the same as B.
Now suppose that we remove the weight of the coin by making a number n (random but finite) of tosses "heads".
How likely is A to win?
Answer - (1/2) ^ (2n + 1), different from B (1/2) ^ (2n + 2).
If we represent on a line each throw of A with the real probability (50%) of coming up heads or tails.
50% ----- 50% ------ 50% ------- 50% ------- .. etc
------- = transition between A's throws where the condition that B takes tails must be met so that A can throw again,
, and we assume that in a finite number of tosses A or B will win the game by going heads to stop the game, On that line, modify the probability (collapse) at each point A threw, now indicating the probability (1/2) ^ (2n + 1) = that its limit is 2/3.
In other words, the same situation, assuming or not that the line will have an end, all the values will be modified at each point.
@@nemethdaniel6384 Isn't turkish a cousin of hungarian?
@@irokosalei5133 Well, far far cousin! :) But indeed, our tribes stopped above the turkish region and some turkish tribes joined to the hungarian tribes before entering the Carpathians (that happened around 965 AC). And of course later (16th - 17th century) the Osmans visited Hungary and stayed for ~ 150 years... so it also contributed to the culture! :) This is why we have also ö,ő,ü,ű and maybe other characters.., and some sounds and words :)
Best way to start the weekend with Arvin's "that's coming up, right now!"
School holidays here in Germany 😋
@@MrGold-17 You mean, some parts of Germany!
I know right, every time I hear that I get so hyped lol
You describe it so clearly i dont know how better anyone can explain this concept. Thanks Arvin
My favorite channel on this app. Definitely helped me ground myself mentally during my quantum physics course. You make mapping these concepts in the head so much easier!
my mouse click seems to be entangled with the like button on this video
Ooooooohh😂😂😂😂
lol
This channel is AWESOME!!!!
Yes! Are you Indian?
कैसे हो भाई?
Agreed 💪🏼
I had to watch it more than once, but this is one of the best videos that explains quantum to classical jump. Thank you very much for taking the efforts to create this beauty
Excellent, Arvin, excellent. Coherence vs decoherence; Quantum vs classical; Present vs time; Aloneness vs interactions; Determined vs uncertainty; Probability vs actuality; Being vs Becoming; all of them features & ingredients in the SALAD OF CHANGE!
When my math teacher in high school said: Infinity is undetermined - he was right. When I asked him why 1/0 is NOT infinity - I was right. We were both right, but we never came to an agreement.
@@curtcoller3632 Infinity is more a workaround in mathematics, it doesn't exist in the physical world.
You made real one of your finest videos, my friend. Thank you for this masterpiece.
I can really thank you Arvin, since you finally fully explained me, way more clearly, the “wave function collapse” and this finally gets me to a more reasonable explanation between past & future. Thanks again, you're a master in teaching such complicated things!
This is the best explanation involving the concepts around the arrow of time I’ve found so far. Thank you!
"This sounds non sensical to a baby"
jokes on you arvin, I am an adult and still dont understand it..
Haha...I said "this sounds non sensical FOR a baby"
@@ArvinAsh sir any update on quantum entanglement why and how it is faster than light I mean what is the medium they use to communicate? A warmhole or anything else?
@@ArvinAsh sir I watched kurzgesagt video of true limit of humanity is there any solution to travel on large distance
as smart as humans get, God is still smarter and better
@@theobvious1958 Always found interesting how the religious revel in trolling, aren't you hold yourself the superior? Or you think troling is the superior thing to do?
"We live in the borderland"
This quote says it all for me! It means we live in the present. This for me describes the borderland of the wave/particle duality. The past is the particle and the future is the wave. The present is the instant when the particle and wave are one in the same. It's bcus we live in this borderland, that we can demonstrate experiments showing waves and particles just based on observation alone. This is why it makes sense that a wave/particle paradox should be the reality for any observer, or to be more accurate, for any measurement of any happening in the universe, even if there is no observer. Slit experiments showing wave patterns are showing us the possible outcomes of what was the future at the moment when we fired the electrons. Slit experiments showing us the double line patterns are showing us the determined outcomes of what became the past when it got measured, meaning the electron's measurement is executed 'before' it hits the photographic plate or in some cases, a computer screen. That's why it doesn't seem to matter if we measure what happened before or after the slits of an apparatus, bcus the measurement is situated to happen before the photographic plate. So, the outcomes are displayed on the photographic plate as particle double line patterns. It should be then, that it only matters if we measure what happened 'after' the electrons strike the photographic plate in the apparatus, to see a wave pattern that is. This is bcus a probability wave when being measured, is equivalent to a probability being collapsed into the sureness of the past, which is the "present" relative to the observer who measured it.
The present is indeed relative as shown in relativity theory, so a probability wave which has collapsed into particle form relative to my own observation, may still be a probability wave relative to another observer who has not yet measured the happening. Disagreement on simultaneity means that what is just a probability relative the latter observer, is actually a certainty relative to myself, since I've already collapsed the wave.
For me personally, this means that probability waves must be deterministic.(I know I know, bear with me)
We can't agree on simultaneity of 2 lightning strikes hitting a train. Suppose I witness the lightning bolts strike at the same time, and yu witness the traincar in the front get struck first, followed by the traincar in the back since you're traveling so fast(we all know this scenario)...
Then I am certain of the determined outcome, that the back of the train has been definitely struck. Yet you are still unaware of the back strike. You only see a probability of the back also getting struck, which represents a probability wave relative to you. But relative to me, I know for sure, this back strike is a certainty. So even though you see only a probability wave and you have no possible method to determine with certainty that a 2nd strike will happen, it is still true, even for the unknowing observer, that the 2nd strike is an unavoidable certainty. Therefoee, probability waves must be deterministic too, am I wrong?
You wouldn't be but you just wouldn't be able know
This is due to something called "super determinism" the future is already set but the universe is set up in such a way that you as an observer will never be able to truly find out
Think God as an example of superdetermism
@@addajjalsonofallah6217 I like the idea of determinism, or superdeterminism if need be...
Another thought of superdeterminism, I think is easy to imagine the fact that any observer who has crossed over an event horizon, has also watched the entire future of the universe unfold already. This must mean our future is already pre-recorded; an inescapable certainty. Our future is already the past relative to anything that has fallen into a black hole.
Arvin you are amazing! I have to listen to your videos more than once and even then sometimes I wonder how much sinks in my brain. But I’m fascinated by the subjects you cover and the way you explain them. You’re very talented and I enjoy learning from you! Thank you
The best presentation I have ever seen for this specific topic - speaking from my heart! I share your arguments and interpretations. Thank you!
Recoherence sounds like a vehicle for reversible computing: that is, doing computing, getting the information, then somehow undoing the computation (in effect resetting the entropic state to an earlier point) while keeping the information. It's one of the holy grails.
The explanations are getting better on this subject. Good video.
One of the best explanations of quantum mechanics and arrow of time I've listened to, and a brilliant link between the two! Keep it up
One of my fav videos from you, hands down!!!! I'd be keen on learning more about that Yale study. So friggin' fascinating and hell yes to living in an ever-unfolding quantum universe, full of possibilities and not certainties. This means having the play of a creator consciousness, building a life by design. My only teeny request is that maybe we could find a different sound for the particles in future videos, it was sort of like... wet? Like someone chewing food or something. Lol. Stellar content as always Arvin, thank you!!
Agreed; I kept thinking of squishy things, but I think that was intentional: There is a certain fluidity to reality; the notion of time flow; change, malleability, all those signify movement which is ever present; The past has solidified; the present is squishy: :0)
Amazing stuff Arvin. It's incredible how much we know about space and time, and how almost 90% of this knlowdege was enlightened in the last hundread years, a blink in human history.
Do we really “know” anything about space and time? We can make some predictions, but it doesn’t equate to knowing.
Anyway, a nice man. A good place to start. 50/50 will scoot you back and a nice place to end.
You are a genius ! You explain complicated things so smoothly 🙏
You are an amazing teacher Arvin! You have a gift which is amplified by your own passion and curiosity for the subjects you discuss. ❤
Magic, science, philosophy, logic altogether starting finally to make sense. You just introduced us to an unbelievably useful way of thinking .Deep, very deep implications. Thank you soo much Arvin, love and appreciation from Greece.
Glad you liked it!
Great video!
In programming, "Lazy Evaluation" is when you don't run a calculation until its result is needed. This is very useful when interactions are sparse.
The universe being mostly empty space, it would make sense for it to be Lazy Evaluated, somehow or other.
When an interaction happens, only the needed properties would evaluated, and entanglement is the further delaying of the unneeded properties. This ongoing evaluation would be the forward movement of time, as Lee Smolin seems to be suggesting. Eventually, perhaps, interactions become fully resolved and are finally forgotten.
As more complex interactions happen more quickly, that forward motion slows in that region of space, which then segues into quantum gravity/spacetime behaviors.
The parallels between QM behavior and practical computer systems design are very interesting to me :)
Ahhhhh it’s always great to wake up to anew Arvin Ash video :D
I've been thinking about this a lot lately. Keep up the good work Arvin.
You think about superposition in your off time?
@@TuAFFalcon i think about time and our reason why in my off time
@@Z3ROWOLFHD We haven't figured out time yet. I don't think we have reason. Stuff and things happened and here we are... I just want to make the most of my life before I rot in the ground.
Man! I'm glad I found this channel. I love the animation... between that and the way you explain it, it helps out a lot
You’re one of my favourite people when it comes to explaining physics for lay people like me. Thanks Arvin!
The most meaningful piece of knowledge I've ever come across
Another great way to wake on a Saturday morning, Coffee and Ash. 🙏🏼 thank you.
Good morning!
Same here, leaning on my motorcycle outside Dunkin Donuts, refill after refill.
I m watching midnight in my timezone. Hope I go to some beautiful quantum dream world 😇
@@ArvinAsh I get so much out of your videos. Thank you for doing them and for maintaining such high standards. I'd love to know where you went to school and where you taught!
@@markdwyer5301 Both at Univ. of Michigan.
Great video and very well choreographed on this advanced subject. It is rewarding to see how well this subject is covered online now.
Your videos are always among the best at explaining these concepts on the border of human understanding. Thank you for educating us with your great content!
Damn! My brain has not been this blown away since I finally understood the Fundamental Theorem of Calculus. Or back in 1969 when I dropped acid. And now my mind is blown again. Thanks, Arvin! 🤪
That was definitely interesting. This whole arrow of time thing, would this mean there's no single arrow of time for the whole universe? Like does everything in the universe go from quantum to classical at the exact same time and rate? Or can this happen at different rates for different objects meaning there's no actual single present?
Arrow of time going backwards?
Excellent video. Very interesting, informative and worthwhile video. Many thanks for the links to the papers.
Arvin Ash is a excellent instructor. The explanation in this video lead me to better understanding of what happens between Quantum and post quantum states. Thanks Arvin.
Now this is a good one. Decoherence versus collapse. Decoherence makes alot more sense. This idea of the collapse is kind of like the "feeling" Newton must have had when he made realizations about gravity. He knew he wasn't right.
Great video as always. Question: how do we reconcile Smolin’s view of time, which seemed to imply the existence of a narrow strip of present (the past having ceased to exist and the future yet to be determined) with the block universe of general relativity (I.e., that my present will share different time slices with your timeline depending on our relative motion and acceleration)?
Thank you so much. This guy’s explanation helps me so much with visualizing these things for better comprehension. Thank you !
Wow! Great video. Thanks for explaining something so complex in such an easily digestable manner !
I need my regular dose of Arvin to remind me that I am not quite as smart as I think I am, cheers bud!
🤔 I am going to need to watch this more than once....
yeah
Thank you my friend! Great video as always, have to watch this kind of videos 2 times just to get my head around it!
Exceptionally good review of an incredibly interesting topic. Drawing decoherence and the experience of the 'now' into a single concept. I shall look out Lee Smolin's paper - Thank you!
This make so much sense. Finally no more “magic”.
Unless you know where it all came from, it still might as well be magic to you.
You wish.
MAgic does not fly well with me.
Everything that happens works in a way or do not happen. Including magic and miracles or witchcraft or whatever you come up with. There's no supernatural don't matter what if something can happen it's natural. If it's possible it's natural. God is natural. The spaghetti monster if it exists it is natural. Existence is the very prove that something is natural
well its still magic, Why is the univers programed like this? This seems very odly specific. If it was backwards or didn't happen time would be messed up. Also energy / gravity effects the flow at which this happens (ie. time slows or hastens)
I attended a couple of "entanglement" parties in the 70's. A few days after one of the parties, it became apparent that some particles' entanglements had tainted other particles. Ah, the 70's.
this actually helps me dealing with my depression, my future is full of possible outcomes, I'll use my intuition to create a better reality.
Arvin, you’re simply the best. Thank you for your wonderful contributions to this world!
I love these uploads
15 mins to watch and weeks to think about it. Top job!
You are like my spiritual guide or something
Thanks!
Arvin!!! this is a Masterpiece!!! What an effort.. saluts man!!
I am so grateful to have found your videos. Thanks for the wonderful job you do!!!
8:18 a.m. Mind already blown!
Future can be altered just with the Thought if one is pure. AWESOME. 😍
That's my God.
Interesting. Can impure thoughts alter future event that is pure?
@@edgarbandoy6646 Sure, For every action there is reaction.
very talented straightforward and simple Love this guy
Great video! really nice profound, yet accessible explanations, thanks.
Past is classical, present is quantum......pretty much sums up the video. Thanks, your videos are very informative. I bunk my online school classes to watch your videos .....
Dear, no need for any online classes if you could understand such a grand subject as quantum physics and no need to bunk the classes.
Great video, Arvin. It all sounds like some kind of quantum entropy. 🤷🏿♂️
it is analogous indeed, but not quite the same process.
Time, what it actually is, and the Arrow of Time, are such deeply profound and perplexing questions. I doubt any serious science lover does not spend considerable "time" trying to establish a finger-hold on how to properly understand it. This video offered a wonderful additional way to think about time, the past, present and future, in terms of that other great mystery, Quantum Mechanics. That there might be a fundamental and intimate relationship that can better help us characterize time, beyond the 2nd law of Thermodynamics, is exciting. It is interesting, and perhaps more than just a coincidence, that both QM and the 2nd law are probabilistic in nature.
What a present to approach to an understanding of these elusive questions through you! Thanks Arvin.
maybe do this one again? this one is hard haha
that theory of how quantum mechanics determines time is crazy
May be some interactions happen when we try to look at the video and it becomes more complex for us to understand! Haha
If "now" is the transition between a "classical past" and a "quantum future," how do we account for the absence of a universal "now"?
The interpretation given here is the one that looks at the concept of time as an emergent phenomenon that is a side effect of quantum entanglement.
This was first fully theorized by Don Page and William Wootters in 1983. but it is based on the Wheeler-DeWitt equation that combines general relativity and quantum mechanics - by leaving out time altogether...
I won't lie, I do find this argument quite compelling, so I'm a bit bias towards the hypothesis.
But an easy way to think of it is that, as you are not causally linked to "now"s other than your own, there is no entanglement shared between your "now" and some other "now". However, were the two causalities to become linked, your "now"s would converge by the degree dictated be the amount required from the given entanglement.
Basically, we will both agree about the "now" of the slice of reality to which we are both causally linked, but we can disagree about the "now" for everything else.
Oh wow this was great! 👍
I coincidentally just happened to read Smolin’s paper last night (a bit late to the party, I know) and have to admit I was intrigued by it. I have to reread it some more and jot down additional notes, but it was very convenient to have read that paper and then noticed this video pop up in my feed!
Beautiful delivery, Arvin. Hope you don’t stop any time soon. 🇺🇸
So this decoherence is a continuous cyclical event that happens as everything affects everything? Sound less like an arrow of time and more like a wave of quantum decoherence that we're surfing on.
That is a clever way to put it. You may be right.
You have to watch it minimum 3 times to understand almost every point clearly. It's really brilliant
Genius explanation, one of the best I've heard on the web - thank you
this is one of the best explanations of quantum states that I have encountered. Thank you so much
0:37 the brainpower in that picture is intimidating
It’s almost like the quantum state is reason for free will, and the act of making a decision makes your life one way or the other.
That not an invalid way to look at it.
Yes, that crossed my mind too seeing this video. Interesting times!
But what if more than one 'free will' contradict one another at the same time and does such information clash or agreement travel at infinite speed across the entire universe? The past is done and future is chosen argument seems probably a bit weak there if there is local free choice. But still, the idea is very inspiring.
You're the best cause of your video illustrations and visuals, love u from the Caribbean
That all actually makes crazy amounts of sense. What an awesome video.
Amazing video as always,me personally i never liked this theory because its basically many worlds in denial lol,this theory makes an interference pattern impossible,if the alternate futures(realities)do not exist they should not interfere with each other.
yeah it is many worlds but somehow the realities that interfeer some how cease to exist wich is more absurd than the realities spliting and being real
There is an artist who has been posting videos for many many years clearly stating that collapse of the way function is the arrow of time. I wish I could remember his name. It made perfect sense to me and this man whoever he is deserves credit.
Thank you for this great and very helpful explanation. I had an insight that an interaction like this plays a significant role, that maybe things work somehow like this.
Amazing as always. Thankyou Arvin Ash
So is decoherence essentially entropy at the quantum level?
It's analogous, but it's a different process.
💪Thank you Mr Ash. In the double slit experiment graphics, you actually exchanged the misleading "measuring eye" for a measurement device. 🙌
Wow. Mind blown. 🤯 Thank you for a very interesting journey.
Where does the past go? Is it recorded somewhere? Is is possible to reproduce it somehow or rewatch it? Without using a video camera obviously :)
It gets eaten by the Langoliers...
Great question! It gets recorded in the quantum states of all the particles in the environment.
Maybe recorded in your brain as memory
"The present is the dividing line between the known past and the unknowable future" is one of those ideas that starts out sounding profoundly insightful until you think about it for a moment, and you realize it's a semantic digression.
Somlin's point is that it is also the dividing line between the quantum and classical - this is the so called, "wave function collapse"
WOW! That was amazing. Thank you for sharing this that was really interesting and enjoyable too.
Arvin you are the man. You could explain multidimensional subspace transwarp physics and I would absolutely understand. You explain things so simply. Thank you!!!!
I think the same 😺
I thought that, if two particles were entangled, and one hit a third partivle, then the original entanglement was lost. At least, so said Leonard Susskind. Please clarify.
Half true.. I think the problem lies in the fact that what Leonard Susskind and others are referring to isn't just entanglement, but entanglement with coherence.
In your example, the original quantum state of the two particle system will be "lost" but a new state of entanglement will arise involving the 3 particles. The COHERENCE will be lost however, although it is possible that you may form a new state of coherence between the three particles, although this can be tricky to pull off.
Quantum entanglement occurs when any group of particles interact in such a way such that the quantum state of each particle of the group cannot be described independently of the state of the others.
So really all the particles in your body, and surroundings, are entangled, but because there are so many particles, all contributing they're own quantum states to the entangled whole, coherence can't be maintained and everything gets.... decohered... decoupled if you will...
The system just gets too noisy to be able to trace exactly how things are entangled. Ironically, this ends up evening out the quantum effects which actually ends up decreasing the uncertainties for the state of the system as a whole.
@@michaelransom5841 "Quantum entanglement occurs when any group of particles interact in such a way such that the quantum state of each particle of the group cannot be described independently of the state of the others. " What is their origin then? how are they ever not entangled with something?
@@BballMGS
The short answer is, in real life, particles are almost always entangled with.. something... at least in areas where there are significant numbers of particles in relatively small spaces.
link to a paper that explains this better than i can... paper labeled "everything is entangled"
www.sciencedirect.com/science/article/pii/S037026931200994X
I'm going to be a bit lazy here and quote a few lines from wikipedia... it does a good job of explaining, so why try and explain it myself.. i'd probably just botch the explanation.. lol..
But just incase you you don't want to read it all.. i'll try and give a way oversimplified TLDR version after..
"Any elements that decohere from each other via environmental interactions are said to be quantum-entangled with the environment. The converse is not true: not all entangled states are decohered from each other.
Any measuring device or apparatus acts as an environment, since at some stage along the measuring chain, it has to be large enough to be read by humans. It must possess a very large number of hidden degrees of freedom. In effect, the interactions may be considered to be quantum measurements. As a result of an interaction, the wave functions of the system and the measuring device become entangled with each other. Decoherence happens when different portions of the system's wave function become entangled in different ways with the measuring device. For two einselected elements of the entangled system's state to interfere, both the original system and the measuring in both elements device must significantly overlap, in the scalar product sense. If the measuring device has many degrees of freedom, it is very unlikely for this to happen.
As a consequence, the system behaves as a classical statistical ensemble of the different elements rather than as a single coherent quantum superposition of them. From the perspective of each ensemble member's measuring device, the system appears to have irreversibly collapsed onto a state with a precise value for the measured attributes, relative to that element. And this provided one explains how the Born rule coefficients effectively act as probabilities as per the measurement postulate, constitutes a solution to the quantum measurement problem."
long and the short of it... any two particles that interact are entangled as so long as the degrees of freedom for each particle have been limited by the interaction between the two particles, however those degrees of freedom can be restored through subsequent interactions with the environment, each interaction setting up a new entangled state. After enough interactions, the limits imposed by the original entanglement are likely to be lost, but the information is still contained in the sum of all subsequent entanglements.
hmm.. that might still be confusing... hmm..
Think of it as future possibilities on a human scale... so right now you have any number of possible things you can do with the rest of your day, but the two most probable are going to the grocery store, or going to a movie. Your friend shows up wanting to go to the movie, now you aren't going to the grocery store and you and your friends future is "entangled". But on the way to the movies you get a phone call and your partner needs to be picked up. So you have to bail on your friend, so your no longer "entangled" with them, and you still have the possibility of going to a movie or going to the grocery store after you pick up your partner. But, the information about your prior "entanglement" persists when looking at the day (system) as a whole as it has changed how the day could have gone, for you, your friend, your partner, and everyone else you've interacted with since you first met (entangled with) you friend, but the further you get from the original interaction, the harder it is to retrace all the interactions, and the smaller the individual contribution of that meeting to the current state of all interactions.
I hope i didn't massacre that too badly.. lol..
Arinash, All of us experience time differently.. based on our physchological condition... What I mean is all of us percieve the same 1 hr differently depending upon whether we are bored or interested or happy or weak, etc.. Now since it is only and only human concoiusness that measures time...how do we know even on the classical scale.. that the time period of say, earth's rotation or a pendulum is constant??
please try to reply to this question!!
I don't think time is purely subjective. There is a real objective time by which quantum systems evolve, and things "happen."
Nice question
look classical things are easy to measure, 9,81
@@ArvinAsh but then I may ask "how do you know that time is a real thing".. Is it because all our theories work pretty well with the concept of time.?. is this belief of TIME just the confirmation bias that began with early humans or galileo measuring his heartbeat, that everyone just continues to believe???!!
@@srajanverma9064 Nobody knows and we'll probably never know the true, genuine reality of these physics laws, because it will always depend on our personal view.
You are Legend Arvin, thanks for another awesome video.
I actually gained a deep understanding. I am thankful for this.
Many thanks Arvin for this great video
After watching your video now it's confirm that backward time travel is not possible.
Is this true in case of blackhole where some time we may enter in our past(theori ally)
Entering in past is also like changing it
Like previously there are 4 people in room now there a 5 (future person) What's your view?
Btw this hats looks cool😂😂 use it in future video also
Well, if Smolin's theory is correct, then yes, there would be no past to go back to. But, I remain open to the possibility.
You could have the "feeling" of time travel if you could "disentangle" a macroscopic group of particles and launch your still entangled self into that group.
But the limitation would be:
1. "You" (the part that travels) are somehow entangled with the group and would need to forget any information about it during the disentangling process.
2. "You" are not entangled in any way with the group and you would gain no advantage of coming from the future, it would be equivalent to just visiting a new location.
@@rodrigoserafim8834 Thanks for intersting info 👍
But I found one loop hole don't know correct or not
1.if I entangled with the group from past then my presence will alter amount of information so isn't that alter future also
2.if I am not entangled with the group then also as observver my presence will effect as some kind of info then also past will affect and so the future
What ur thoughts?
@@avadhutd1403 I think in this kind of interpretation of the quantum entanglement process our notion of "past" and "future" don't really exist as such. That is kind of a good thing because it solves the general relativity problem of the "present slice" in a block universe where two observers can get completely different chronological classifications of an event.
As to your questions, you are not so much going to the past as you are reverting a group of particles to a previous quantum state while keeping yourself isolated from that process. In human terms you would be kind of bringing the past into the present and that would be indistinguishable from you traveling to the past.
Information would increase globally continuously. So in a sense this localized "time travel" would be moving into a universal future.
I talked in groups of particles because I think its impossible to bring the entire universe into the past around you. To disentangle something you have to entangle another portion of the universe. The best you can achieve is to remain isolated from that process while it happens (i.e. you can't do it yourself) and then be brought to it still in isolation.
Just my 2 cents. I'm just a layman in these matters.
@@rodrigoserafim8834 That's a great explaination
By reading this I can say one thing ur proffesation may be different but u have deep knowledge in quantum physics.
If we want to find basic nature of reality then we require to involve many many people around the world.
Due godel's incompleteness theorem we may not find theory of everything I am happy to listen your view on this theorem
But anyway as we progress in physics we will get pretty amazing gift from physics like I internet, mobile , quantum computer
That's my thoughts
Wish you a good health to you and your family 👍👍
at last . uploaded
I came to very similar conclusions few months ago about the nature of reality after thinking in double slit exp.
Good video as usual.
Fascinating video! Love this channel!
I will pretend as I understand everything you explained 😁
There can be no enlightenment for an atheist
I understood it
It becomes classical physics after the langoliers eat the other sides of the waveform.
Great book
Second time eatching this video. It has helped my understanding about Quantum particles a lot. Its easier to understand whats written in the books and I dont have to read 10× to get a idea of what is in there. Thank you!
Great video, Arvin! Thanks 😎