[SEQ RERUN] Spooky Action at a Distance

MinibearRex

Today's post, Spooky Action at a Distance: The No-Communication Theorem was originally published on 05 May 2008. A summary (taken from the LW wiki):

As Einstein argued long ago, the quantum physics of his era - that is, the single-global-world interpretation of quantum physics, in which experiments have single unique random results - violates Special Relativity; it imposes a preferred space of simultaneity and requires a mysterious influence to be transmitted faster than light; which mysterious influence can never be used to transmit any useful information. Getting rid of the single global world dispels this mystery and puts everything back to normal again.

Discuss the post here (rather than in the comments to the original post).

This post is part of the Rerunning the Sequences series, where we'll be going through Eliezer Yudkowsky's old posts in order so that people who are interested can (re-)read and discuss them. The previous post was Bell's Theorem: No EPR "Reality", and you can use the sequence_reruns tag or rss feed to follow the rest of the series.

Sequence reruns are a community-driven effort. You can participate by re-reading the sequence post, discussing it here, posting the next day's sequence reruns post, or summarizing forthcoming articles on the wiki. Go here for more details, or to have meta discussions about the Rerunning the Sequences series.

Today's post, Spooky Action at a Distance: The No-Communication Theorem was originally published on 05 May 2008. A summary (taken from the LW wiki):

As Einstein argued long ago, the quantum physics of his era - that is, the single-global-world interpretation of quantum physics, in which experiments have single unique random results - violates Special Relativity; it imposes a preferred space of simultaneity and requires a mysterious influence to be transmitted faster than light; which mysterious influence can never be used to transmit any useful information. Getting rid of the single global world dispels this mystery and puts everything back to normal again.

Since you don't have absolute time, you don't have a unique wavefunction of the universe evolving in time, and you can't reduce everything to a unique flow of amplitudes through configuration space.

Hmmm, you're right. (Of course I could just pick a favoured reference frame, but that's inelegant. Timeless physics might work too (I think?), but the sequence reruns will get to that question in due time.)

Also, we had a similar discussion here.

EDIT: Would you agree that what I said was the same as what Eliezer is saying in the QM sequence?

EDIT2: Okay, my brain's just melted. What does it even mean for a QM theory to obey SR? I don't know how to apply Lorentz transformations to a wavefunction.

I don't know how to apply Lorentz transformations to a wavefunction.

The wave function is a scalar in the regular QM, so it is unchanged under the Lorentz transformations. Unfortunately, the Schrodinger equation is inherently non-relativistic.

The Klein-Gordon and Dirac equations were the early attempts to "relativize" the Schrodinger equation. It didn't work that well until the wave function was replaced with quantized fields. Those quantized fields become photons, electrons and other particles in a certain approximation. Unfortunately, the mat... (read more)

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