When a quantum coin-flip happens at A the universe splits everywhere at the same time. So position B is also split.
This is incorrect. "World-splitting" propagates at the speed of decoherence, and this is not instantaneous.
"World-splitting" propagates at the speed of decoherence, and this is not instantaneous.
Decoherence is just another word for interaction.
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):
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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.
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