Oof, the amount of misinformation on QM even here on LW is staggering.
Physics no longer describes what can happen.
This is straightforwardly false. Maybe you meant to say “Physics no longer describes what definitely happens”? Still misleading, as that was already the case with statistical mechanics within the ontology of Boltzmann and Gibbs 50 years earlier.
Oh, and the tree is emergent by the way, it’s not even a base component of the ontology.
Coherent phenomena are definitely part of the base ontology of QM. The density matrix encodes the ensemble. (If by “the tree” you didn’t mean the ensemble, then your statement would make even less sense to me).
...QM will tell you that what it means to be a function has changed and you have to do it differently now.
No. QM has no bearing on “what it means to be a function”. Maybe you mean “QM encodes permutations in a surprising way”?
Except that QM can tell the difference between a 360 degree rotation and doing nothing. (Not 720 degree rotations though. Those are still just like doing nothing, so at least there’s that.)
Strictly speaking this is only sometimes true. It seems like you are alluding to the spin-statistics theorem or maybe the Aharonov-Bohm effect or Berry phase. Your quoted statement is specifically applicable only to fermionic states. It’s inapplicable to bosons or more exotic states like anyons (FQHE) or braid statistics.
Because of the way QM works, it’s actually possible to exploit it to perform some kinds of computations faster than seems to be possible classically. This is also kind of weird.
Thanks for the notes. I’ve made a few edits to my comment above based on this.
Also, for the benefit of the folks reading this: I’m not alluding to spin-statistics or Berry phase, merely the use of instead of as the group of rotational symmetries.
Oof, the amount of misinformation on QM even here on LW is staggering.
This is straightforwardly false. Maybe you meant to say “Physics no longer describes what definitely happens”? Still misleading, as that was already the case with statistical mechanics within the ontology of Boltzmann and Gibbs 50 years earlier.
Coherent phenomena are definitely part of the base ontology of QM. The density matrix encodes the ensemble. (If by “the tree” you didn’t mean the ensemble, then your statement would make even less sense to me).
No. QM has no bearing on “what it means to be a function”. Maybe you mean “QM encodes permutations in a surprising way”?
Strictly speaking this is only sometimes true. It seems like you are alluding to the spin-statistics theorem or maybe the Aharonov-Bohm effect or Berry phase. Your quoted statement is specifically applicable only to fermionic states. It’s inapplicable to bosons or more exotic states like anyons (FQHE) or braid statistics.
Indeed.
Thanks for the notes. I’ve made a few edits to my comment above based on this.
Also, for the benefit of the folks reading this: I’m not alluding to spin-statistics or Berry phase, merely the use of