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comment by Shmi (shminux) · 2019-12-21T19:49:33.363Z · LW(p) · GW(p)
Idle speculating is fun and all, but consider reading an academic book or two on the topic. Then learn and do the math. I could point out the errors in the above, like confusing classical and quantum bits, but it's best if you do it yourself some day.
Replies from: lsusr↑ comment by lsusr · 2019-12-21T21:23:05.158Z · LW(p) · GW(p)
I could point out the errors in the above, like confusing classical and quantum bits...
Could you point out the errors please?
It's not obvious to me why the difference between classical and quantum bits matters in this thought experiment because superposition and entanglement are not supposed to be part of it. I did admittedly gloss over how a quantum bit needs to be measured to force it into one of two states. Does that really invalidate the thought experiment?
[C]onsider reading an academic book or two on the topic. Then learn and do the math...it's best if you do it yourself some day.
I read several academic books on physics and math when I got my bachelor's degree in physics and math. I drilled freshman-level special relativity and quantum mechanics many times when I tutored these subjects. The footnote on Baryon asymmetry is indeed wild speculation, but the rest of the microstate/macrostate stuff generalizes from a statistical mechanics class I took in my sophomore year of college. Which additional math do you recommend I learn how to do?
Replies from: shminux↑ comment by Shmi (shminux) · 2020-01-14T03:44:49.969Z · LW(p) · GW(p)
Suppose a universe is made up of 16 quantum particles each of which has two states: 0 and 1. In this sense, the entire universe is just a number like 0b0000000000000000.
Well, if your universe is just two states, its description in the eigenstate basis would be something like A1 exp(iE1 t)|1> + A2 exp(iE2 t), where A1 and A2 are complex and E1 and E2 are real (modulo normalization and phase). I am not sure how this maps into a finite length binary number.
Replies from: lsusr
↑ comment by lsusr · 2020-01-20T07:29:12.402Z · LW(p) · GW(p)
It maps to a finite length binary number if you force the particle into one of two states. So you could think of this universe as equidistant (in time) instants of a continuous universe where positions are measured, then they're let to evolve and then positions are measured again. The binary strings refer only to the snapshots where the continuous universe is measured.
This ignores the fact that there must be something to measure the particles with. The goal of this thought experiment is to play around with the Born rule [LW · GW] while ignoring the time evolution of a wave function governed by the Schrödinger equation.