Many Worlds, EPR and ER=EPR

[Bob Walance]

TL;DR Summary

A question about EPR, ER=EPR and the Many Worlds theory

This question is not intended to invoke arguments about whether Hugh Everett's theory, now referred to as the Many Worlds Interpretation of Quantum Mechanics, is feasible or not.

When I heard David Wallace say that Many Worlds does away with the so-called 'spooky action at a distance' referred to in the EPR paper, I bought Sean Carroll's book 'Something Deeply Hidden'.

From page 105 of Carroll's book talking about 'spooky action', he seems to confirm Wallace's assertion:
"The correlations don't come about because of any kind of influence being transmitted faster than light, but because of branching of the wave function into different worlds, in which correlated things happen."

This makes sense to me. If I have two entangled particles in a simple Bell pair, then in Many Worlds both terms exist before and after measurement. If I measure both particle spins as being up then there is another branch of the universe where both spins would be measured as down. So, in Many Worlds the EPR objections just don't apply.

My question is, in the Many Worlds interpretation isn't it also the case that there is no need for wormholes connecting entangled particles - as in ER=EPR?

 

[PeterDonis]

Moderator's note: Moved thread to the QM interpretations forum.

 

[Demystifier]

Summary: A question about EPR, ER=EPR and the Many Worlds theory

My question is, in the Many Worlds interpretation isn't it also the case that there is no need for wormholes connecting entangled particles - as in ER=EPR?

ER=EPR is a conjecture proposed to resolve the black hole information (BHI) paradox. There are many attempts to resolve the BHI paradox in other ways, without ER=EPR. In particular, Carroll and others have argued that many worlds interpretation can resolve the BHI paradox. But to be honest, neither of the solutions of the paradox proposed so far seems very convincing. So the answer to your question is: maybe, we don't know.

My own opinion is that many worlds alone cannot resolve the BHI paradox, the paradox is deeper than that. I also think that ER=EPR taken literally cannot be true. Nevertheless, I am quite sympathetic with the idea that wormholes could somehow be essential to solving the BHI paradox.

 

[DrChinese]

From page 105 of Carroll's book talking about 'spooky action', he seems to confirm Wallace's [MWI] assertion:
"The correlations don't come about because of any kind of influence being transmitted faster than light, but because of branching of the wave function into different worlds, in which correlated things happen."

This makes sense to me. If I have two entangled particles in a simple Bell pair, then in Many Worlds both terms exist before and after measurement. If I measure both particle spins as being up then there is another branch of the universe where both spins would be measured as down. So, in Many Worlds the EPR objections just don't apply.

This does not explain Bell. With Bell, the issue is the correlations when the measurement bases are NOT identical. That is where the Bell inequalities arise. Keep in mind that the measurements are not local, so any effect in MWI is necessarily nonlocal - despite protestations to the contrary.