Yeah… to paraphrase Deutsch, that just sounds like multiple worlds in a state of chronic denial. Also, it is possible for other Everett branches to influence yours, the probability just gets so infinitesimally tiny as they decohere that it’s negligible in practice.
the probability just gets so infinitesimally tiny as they decohere that it’s negligible in practice.
(Is this true even when we apply pressure to it (as in, can we design machines or systems that leverage this systematically)? And are there are actually no macroscopic phenomena that are downstream of branches interacting? Like, I feel like one could have said such a sentence about relativity a few decades back, but it would have been pretty obviously wrong, and you end up with weird stuff like black holes if you take relativity seriously. I feel like I would be quite surprised if we ended up with no macroscopic phenomena that doesn’t require explicitly modeling the interference by distant branches.)
Like I mention in the paper, the largest object for which we’ve done this so far (at least that I’m aware of) is Carbon 60 atoms which, while impressive, are far from “macroscopic.” Preventing a superposition from decohering is really, really difficult—it’s what makes building a quantum computer so hard. That being said, there are some wacky macroscopic objects that do sometimes need to be treated as quantum systems, like neutron stars (as I mention in the paper) or black holes (though we still don’t fully understand black holes from a quantum perspective).
There is some reason to think we will never see effects that depend on the other Everett branches, because we could say that a branching event has occurred precisely when the differences between the two components are no longer effectively reversible.
Yeah… to paraphrase Deutsch, that just sounds like multiple worlds in a state of chronic denial
Motl’s point was the opposite..that MWI is Copenhagen in denial because you keep having to get out your eraser and discard what you did not observe. (Which is relevant to the claim that MWI is simple: in terms of the minimal amount of calculation you need to do to get results, it is not simpler).
Yeah… to paraphrase Deutsch, that just sounds like multiple worlds in a state of chronic denial. Also, it is possible for other Everett branches to influence yours, the probability just gets so infinitesimally tiny as they decohere that it’s negligible in practice.
(Is this true even when we apply pressure to it (as in, can we design machines or systems that leverage this systematically)? And are there are actually no macroscopic phenomena that are downstream of branches interacting? Like, I feel like one could have said such a sentence about relativity a few decades back, but it would have been pretty obviously wrong, and you end up with weird stuff like black holes if you take relativity seriously. I feel like I would be quite surprised if we ended up with no macroscopic phenomena that doesn’t require explicitly modeling the interference by distant branches.)
Like I mention in the paper, the largest object for which we’ve done this so far (at least that I’m aware of) is Carbon 60 atoms which, while impressive, are far from “macroscopic.” Preventing a superposition from decohering is really, really difficult—it’s what makes building a quantum computer so hard. That being said, there are some wacky macroscopic objects that do sometimes need to be treated as quantum systems, like neutron stars (as I mention in the paper) or black holes (though we still don’t fully understand black holes from a quantum perspective).
Ah, yeah, neutron stars do feel like a good example. And I do just recall you mentioning them.
There is some reason to think we will never see effects that depend on the other Everett branches, because we could say that a branching event has occurred precisely when the differences between the two components are no longer effectively reversible.
Motl’s point was the opposite..that MWI is Copenhagen in denial because you keep having to get out your eraser and discard what you did not observe. (Which is relevant to the claim that MWI is simple: in terms of the minimal amount of calculation you need to do to get results, it is not simpler).