Are there degrees of quantum entanglement?

[CosmicVoyager]

Greetings,

Are there degrees of quantum entanglement? After entangled particles interact with others particles do they continue to be entangled to some degree? Becoming less entangled the more interactions that occur? So that there is complex network of entanglements?

If so, could it be that seemingly random phenomena such as when an electron emits a photon and radioactive decay be determined by quantum entanglements?

Thanks

 

[DrChinese]

Greetings,

Are there degrees of quantum entanglement? After entangled particles interact with others particles do they continue to be entangled to some degree? Becoming less entangled the more interactions that occur? So that there is complex network of entanglements?

If so, could it be that seemingly random phenomena such as when an electron emits a photon and radioactive decay be determined by quantum entanglements?

Thanks

There are a lot of unknown questions about entanglement. Many cases are nearly impossible to determine by experiment because the effects are too subtle to observe. I would say that the general theoretical answer is:

a) There are definitely degrees of quantum entanglement for a pair of entangled particles. For example: momentum position entanglement with OR without spin entanglement.
b) Conceptually, any number of particles can be entangled.
c) There is even something called Entangled Entanglement. A particle is entangled with a system of particles, which is itself entangled.

Presumably, entanglement could occur with the weak force as well. Not sure how that would work. I am not sure that random phenomena are ever "explained" by entanglement. But maybe that would become clearer at a certain point.

 

[bobbytkc]

Greetings,

Are there degrees of quantum entanglement? After entangled particles interact with others particles do they continue to be entangled to some degree? Becoming less entangled the more interactions that occur? So that there is complex network of entanglements?

If so, could it be that seemingly random phenomena such as when an electron emits a photon and radioactive decay be determined by quantum entanglements?

Thanks

Yes indeed, there are degrees of entanglement. There are even measures of how entangled these particles are, such as the von neumann entropy, and the purity of a single particle in an entangled pair of particles, or the amount of violation of some Bell's inequality.

Entanglement between particles are also generally made using interactions. For example, say you have two non entangled particles and you would like to create entanglemend between them. One way to do is to make them interact with each other, for example, magnetic magnetic interaction from the spins of particles. Such interactions generally create an entangled system. In fact, when systems are interacting with each other, they are (usually) found in some entangled state. So one of the open questions in physics is: macroscopic objects are generally interacting with the environment all the time, so why is it that the macroscopic world do not display features of an entangled state?

 

[K1NS]

Please take a moment to answer a newbie question.

My understanding of quantum entanglement is that a pair of particles can instantaneously interact even if they are separated by great distances.

But doesn't this just mean that even though they may be separated in our 4D spacetime, they may be adjacent (or even coincident) in another dimension? I thought that string and brane theories postulated 11 or more dimensions. Maybe entangled particles occupy or comprise the same string? It seems to me that quantum entanglement is a way for us 4 dimensional creatures to observe higher dimensions.

And if this turns out to be true, could it not open the door to the possibility of instantaneous long-distance communications?

 

[DrChinese]

Please take a moment to answer a newbie question.

My understanding of quantum entanglement is that a pair of particles can instantaneously interact even if they are separated by great distances.

But doesn't this just mean that even though they may be separated in our 4D spacetime, they may be adjacent (or even coincident) in another dimension? I thought that string and brane theories postulated 11 or more dimensions. Maybe entangled particles occupy or comprise the same string? It seems to me that quantum entanglement is a way for us 4 dimensional creatures to observe higher dimensions.

And if this turns out to be true, could it not open the door to the possibility of instantaneous long-distance communications?

Well, yes and no, we are now getting into some semantic and philosophical difficulties.

If is fine to think of quantum spacetime as being nonlocal in the manner you describe (adjacent or coincident). But you can't then twist that description to something that the math does not support. There are a number of theorems that explain/prove that QM does not support FTL signaling.

So you might be correct if QM is wrong.