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Quantum Entanglement

PeacefulChaos
Posts: 2,610
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4/28/2014 4:32:53 PM
Posted: 2 years ago
I just recently learned about quantum entanglement and how it relates to time. From my current understanding, entanglement is a phenomenon by which multiple particles become linked in such a way that we can't really consider them as separate quantum states, so we put them all into one quantum state.

My question here is how quantum entanglement relates to the observer effect (where a particle appears to have multiple eigenstates, or possible places and speeds it could exist at, but when observed only has a single eigenstate). Is this effect actually just us becoming entangled with the particles being observed? The reason I ask is because of an experiment done by Ekaterina Moreva in Italy, where they determined that an internal observer entangled with the particles would see a change in time between the polarization between two photons, while an external observer would observe a static system. Essentially, this proves that time is a product of quantum entanglement.

The way time seems to vary depending on whether it is observed or not greatly relates to the problem we encounter with the observer effect. Wouldn't this suggest that the observer effect is also a product of quantum entanglement?

My curiosity was sparked by reading this debate:

http://www.debate.org...
Bannanawamajama
Posts: 125
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4/29/2014 8:32:04 AM
Posted: 2 years ago
The observer effect isn't necessarily the same as entanglement because entanglement doesn't cause a waveform of a quantum particle to collapse, but the observer effect does. When you observe any kind of particle, you necessarily have to put some additional constriction on it. If you are observing it visually for example, that involves bouncing a photon off it, which will affect the momentum of the particle and thus change the state it is in, with that perturbation causing the waveform to change.

But with entanglement, the particle stays in its superposition of different states, not yet collapsing. But when it does collapse, that in turn will put a specific constraint on its entangled partner, because their waveforms are sort of synchronized so to speak, so the collapse of one will dictate the end state of the other.
PeacefulChaos
Posts: 2,610
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4/29/2014 11:20:24 AM
Posted: 2 years ago
At 4/29/2014 8:32:04 AM, Bannanawamajama wrote:
The observer effect isn't necessarily the same as entanglement because entanglement doesn't cause a waveform of a quantum particle to collapse, but the observer effect does. When you observe any kind of particle, you necessarily have to put some additional constriction on it. If you are observing it visually for example, that involves bouncing a photon off it, which will affect the momentum of the particle and thus change the state it is in, with that perturbation causing the waveform to change.

But with entanglement, the particle stays in its superposition of different states, not yet collapsing. But when it does collapse, that in turn will put a specific constraint on its entangled partner, because their waveforms are sort of synchronized so to speak, so the collapse of one will dictate the end state of the other.

I'm not saying that the two are the same, but rather that the observer effect occurs as a result of quantum entanglement. If a person isn't entangled with the particles, how could the observer effect even occur? After all, in order to take measurements of particles and see a change, you have to get entangled with the particles, right?
Bannanawamajama
Posts: 125
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4/29/2014 12:16:38 PM
Posted: 2 years ago
You cant entangle a person as a whole with a particle, entanglement occurs on a particle to particle basis. But even if you were entangled with a particle, and you were measuring say, spin of an electron. If you measured it, then it would have a specific spin and some electron in your body would have the opposite. That doesn't really change anything or have anything to do with your measurement or how you perceive the electron.

But no, you don't have to entangle yourself with a particle to measure it, those aren't the same thing. All you're doing is adding an extra potential to suppress the possibilities of where the particle can go/be. The fewer things blocking a particle, the more it behaves in a wavelike nature, which is why its not in any one state, but when you suppress it it starts behaving more particle like so you can get a more definite idea of where it is
PeacefulChaos
Posts: 2,610
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4/29/2014 4:56:44 PM
Posted: 2 years ago
At 4/29/2014 12:16:38 PM, Bannanawamajama wrote:
You cant entangle a person as a whole with a particle, entanglement occurs on a particle to particle basis. But even if you were entangled with a particle, and you were measuring say, spin of an electron. If you measured it, then it would have a specific spin and some electron in your body would have the opposite. That doesn't really change anything or have anything to do with your measurement or how you perceive the electron.

But no, you don't have to entangle yourself with a particle to measure it, those aren't the same thing. All you're doing is adding an extra potential to suppress the possibilities of where the particle can go/be. The fewer things blocking a particle, the more it behaves in a wavelike nature, which is why its not in any one state, but when you suppress it it starts behaving more particle like so you can get a more definite idea of where it is

My apologies, I used the term "entangle" far too loosely (although, it is possible for entanglement to occur between groups of particles such that the entire system has a quantum state). I'd like to clarify. Perhaps a better word to use would be an "internal" observer versus an "external" observer. What do I mean by this? This experiment will demonstrate:

http://arxiv.org...

We clearly see that the only way to get measurements and observe a change of some kind among particles is to become an internal observer versus an external one. While the external observer will not perceive any differences, the internal observer will. This is somewhat similar to the observer effect, in which an "external" observer (that is, one who hasn't decided to actually take a measurement of the particles) sees that the particle has no definite position; however, upon taking a measurement, the observer becomes an "internal" one and sees that the particle does have a definite position due to the collapse of the wave function.

This is why I initially thought there would be a link between quantum entanglement and the observer effect, but I suppose I was wrong. Thank you for clearing that up for me.

Also, do you happen to know why the act of observing suppresses the particles in such a way that the wave function collapses to a single eigenstate? Or is this something that still hasn't been explained properly?
slo1
Posts: 4,346
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4/30/2014 5:42:59 AM
Posted: 2 years ago
There are no answers to your questions. How and what causes the collapse is only hypothesize at this stage.

First and foremost one has to believe that when a non conscious entity is not observing by taking a measurement that any other particles that come in contact become entangled and put in the suppisitional state. This mean when Schr"dinger's cat becomes entangled with the quantum system and nobody looks in the box it is in a state of being alive and dead at the same time until someone looks.

Some hypothesize a particle random collapse every 300 million years or so. If that were true there are enough particles in a cat that one would collapse causing a collapse off all the other particles in the cat, so it would only be in a suppositional state for a split second.

Other hypothesize that it is consciousness that causes the collapse. Does a cat have enough consciousness to collapse it itself? A human looks at the box, so that is collpsed. If the cat touched the box does it cause it to collapse?

Nobody really knows about what the collapse is. It appears that consciousness is involved because the observer has to choose how to measure in order to cause collapse. That includes whether they are observing from inside or out side the system. A measuring device that is not observed will not cause a collapse. Of course on has to believe the cat is dead and alive at the same time in that case.

With that said correlation does not equal causation. Conciousness and the mystery of quantum mechanics is only now becoming an acceptable field of study in science. Before it was career suicide.