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Quantum Entanglement Drives the Arrow of Time

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Re: Quantum Entanglement Drives the Arrow of Time

#61

Post by sfk »

aaren wrote: post #25
throwaway7548 wrote: post #21

I have a question. I just went to a source of physical (quantum) randomness http://www.randomnumbers.info/ and I'm giving you a random number between 0 and 10,000 which I've just generated there. Here it goes: 6296. Ok. Now that light cone had finally reached you. And you (neurons in your brain to be precise) are thoughtfully entangled with that random event (outcome), now in your past. Now imagine the following. A f…

> There are no entanglements any more which link you to that event. Not directly, but the information has spread out from your neurons into the surrounding matter ad nauseum. It's just we can't interpret the information anymore. The event still happened in your past, you just can't see it through your limited human view of reality.

ad nauseam

Re: Quantum Entanglement Drives the Arrow of Time

#62

Post by arethuza »

loup-vaillant wrote: post #57
cromwellian wrote: post #3

This Google Talk https://www.youtube.com/watch?v=dEaecUuEqfc uses entanglement and quantum information theory in a clear and understandable way to explain 'spooky' quantum phenomena, like the quantum eraser, de-coherence, the aspect experiment, and the measurement problem. Even if you don't know any QM, just basic algebra and calculus, it's really approachable. I used to be a fan of the Many Worlds interpretation, bu…

I must say, I'm not sure what he even means by this "zero universe" business. Sure, the classical illusion is bust, but the wave function itself, as far as we know, is real, is it not? While we're at throwing quantum explanation links, here is the Quantum Physics Sequence on Lesswrong: http://lesswrong.com/lw/r5/the_quantum_physics_sequence/ I'd say the math is even simpler there, yet the explanation go deeper. It's…

Doesn't it depend on what it means for a theoretical construct to be "real" or not? Isn't "does it work" a better question?

Re: Quantum Entanglement Drives the Arrow of Time

#63

Post by baddox »

x3c wrote: post #46
baddox wrote: post #39

Earlier quoted context omitted.

Probability theory is how we model the arrow of time, but it's not a physical mechanism by which the arrow of time occurs. The article covers this distinction.

Isn't the classical definition of Arrow of time is from the system with less entropy to a system with more entropy? What is lacking in this definition of Arrow of time that we need to take it to Quantum level?

Again, probability is just a model that can predict something, but not explain how it works. Take a pseudorandom number generator and do rand() > 0.5. Your probability is 50%, and that is a pretty good model to predict how the subroutine will behave, but it may also be useful to understand what algorithm the PRNG is using.

Re: Quantum Entanglement Drives the Arrow of Time

#64

Post by mbq »

This is nonsense; entropy and the arrow of time are essentially a many-body effects and require no quantum effects to occur. A simplest way to see it is to make small simulation of a, say, 1000 gas particles with only classical bouncing in a one side of a box partitioned in half with a barrier, obviously with a time-reversible numerical method -- after the removal of the barrier the gas will evenly spread over the box without any entanglement.

Re: Quantum Entanglement Drives the Arrow of Time

#65

Post by mtrimpe »

joe_the_user wrote: post #55
dalek_cannes wrote: post #15

Do we need entanglement to explain the Arrow of Time? Even though in classical mechanics, the past and the future are both equally observable, we remember the past and not the future because the future does not contain certain information yet -- the information to be introduced into the universe in the form of quantum fluctuations. One could even argue that all information in the universe was created at some point in…

Well, Information is produced in the course of a system evolving and information is destroyed (the past is forgotten). The tendency of a system to move towards greater entropy could be said to give an explanation for the difference between past and future. But how does that work in an open system like the planet earth, where entropy hasn't increased, where the system has self-organized over time. The ability of a sys…

I always like the crazily simplified explanation: to truly undo something you need to undo your memory of it as well.

Re: Quantum Entanglement Drives the Arrow of Time

#66

Post by one-more-minute »

This is an interesting step, but doesn't actually explain why time is asymmetrical. Ok, so things equilibrate as time moves forwards because they entangle as time moves forwards. But this just shifts the question – why is entanglement asymmetrical when time, when the underlying laws are not?

You still have the same problem: if you reverse time, the states become untangled and the coffee heats up.

It's nice to be able to model this from a quantum perspective, but make no mistake – no philosophical issues have been resolved here, and we don't "finally" understand anything we didn't before.

Re: Quantum Entanglement Drives the Arrow of Time

#67

Post by goldenkey »

alxndr wrote: post #17
elzr wrote: post #5

This was surprisingly beautiful. As a geek in programming/computers/information/mathematics, but only a physics admirer from afar, it is very suggestive, even natural, to explain the deepest physical reality in terms of information: "It was as though particles gradually lost their individual autonomy and became pawns of the collective state. Eventually, the correlations contained all the information, and the individu…

Makes me imagine anthropomorphized variables in a program having discovered the file system and the class definitions that they're instantiated from, but are still trying to figure out what RAM is...

I laughed at how clever the analogy is. Time is relative to us as observers, the arrow of time is fundamental I would think.

Re: Quantum Entanglement Drives the Arrow of Time

#68

Post by [deleted] »

tim333 wrote: post #8

The reasoning sounds a bit iffy as in: “Finally, we can understand why a cup of coffee equilibrates in a room,” said Tony Short, a quantum physicist at Bristol. “Entanglement builds up between the state of the coffee cup and the state of the room.” I think you can understand coffee cooling quite well without any quantum stuff - the atoms in the coffee are moving faster than those in the room. There will be a tendency…

[deleted]

Re: Quantum Entanglement Drives the Arrow of Time

#69

Post by sheerun »

I love following article: http://www.flownet.com/ron/QM.pdf

It basically shows that observation (measurement) and entanglement are the same things.

Think about it: particles are not magically going out of superposition as we observe (measure) them. We (our atoms) become entangled with those particles, we become superposition. It's just propagation of entangled state.

Why we don't perceive ourselves as in superposition? "It turns out that this result generalizes to any number of mutually entangled particles. If we ignore any one particle, the entropy diagram of the remaining particles looks like a system of N-1 particles in a classically correlated state with a non-zero entropy.". That means each atom of our bodies perceives other atoms entangled with it as they were not in any superposition (though as a whole, the system is still in superposition). We (atoms) are constantly entangled and in superposition with our environment, but we perceive it as classical state.

In what state each atom "sees" every other? According to probability. That's why in double slit experiment we see only one of most probable outcomes, not a random one.

Time could be rate of entanglement propagation. Entanglement propagates with speed of light (speed of particles), so we seem live in same timeline. But if something moves away from us with speed of light, the time for this object goes slower, but only relative to us.

Until two particles interact with any way, they live in totally different timelines. After they "observe" each other (entangle with each other), also their time becomes entangled. That's why after we see a cup begin dropped, it becomes part of our reality, and the cup becomes broken in our time.

We live in spacetime. As mentioned in article "“Spooky action at a distance” ought to be no more and no less) mysterious than the “spooky action across time” which makes the universe consistent with itself from one moment to the next.".

Why arrow of time? The article says: "Under QIT, a measurement is just the propagation of a mutually entangled state to a large number of particles. To reverse this process we would have to "disentagngle" these quantum states. In principle this is possible. In practice it is not.". I think differently though.

That are my thoughts. Please don't judge :)

Re: Quantum Entanglement Drives the Arrow of Time

#70

Post by [deleted] »

dalek_cannes wrote: post #15

Do we need entanglement to explain the Arrow of Time? Even though in classical mechanics, the past and the future are both equally observable, we remember the past and not the future because the future does not contain certain information yet -- the information to be introduced into the universe in the form of quantum fluctuations. One could even argue that all information in the universe was created at some point in…

[deleted]
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