One of the reasons people have studied FQHE has been to create (non-abelian) anyons and thereby a framework for topological quantum computing. Is that also the story here?
> [Scott Aaronson, Computer Science professor and director of the University of Texas Quantum Information Center,] doesn't understand [Quantum Mechanics] and shouldn't act like they do.
This conspiracy theory is so weird and detailed. I don’t take it particularly seriously, but I would be less shocked if aspects of it turn out to be true than some other conspiracy theories.
And just because it's exotic, that doesn't mean it's not useful to think about. My impression from some rather limited exposure to quantum chemistry is that the molecule hits a sweet spot where it's both not completely trivial to solve, yet within the capabilities of present-day quantum computers, meaning that it becomes a useful benchmark for algorithm development. See e.g. https://arxiv.org/abs/2303.07417 (which covers H₄ and LiH) and the references therein.
> The first is that the SSH protocol provides to the server all public keys the client is willing to produce signatures for, which by default are all the public keys in your ssh-agent and in your ~/.ssh/id_*.
Not sure about other systems, but this isn't the default on Debian. I, at least, start every day by running `ssh-add ~/.ssh/id_whatever_service_I_want_to_auth_to`, because it doesn't do it by itself, and I was too lazy to configure it. For the same reason, the party trick didn't work here, since I haven't had to commit anything today yet ...
> Is wave function collapse is a real thing or just an approximation of what happens when a large system is entangled?
I've listened to enough Carroll to convince myself that I think MWI makes sense, but what I never got is that it doesn't seem to offer much in terms of explanation of how the entangled state ends up being what it is: We see a particular result of an experiment with many possible a priori outcomes, but is there a mechanism that determines which particular entangled state we end up in? Something like the phases of the wave functions on individual Hilbert space sectors conspiring to produce a certain outcome, so that an omnipotent observer with full access to both parts would be able to tell what happens a priori, no dice being rolled? Or is that just hidden variable theory?
> it doesn't seem to offer much in terms of explanation of how the entangled state ends up being what it is:
According to MWI, all possible results of an experiment are manifest and real. You're asking "which particular entangled state we end up in?". You end up in all of them. For a 2-state superposition system, there are 2 versions of "you" that exist after the experiment, both of which are equally real. Subsequent measurements of the quantum system will appear to be "collapsed" for both versions of you but each will see different and opposing values.
Except that I've only ever experienced ending up in one of them, so exactly how did the "I" that is typing this right now wind up here, and not in some other branch?
There's an unexplained bifurcation of consciousness implied by MWI which it cannot explain (although I think it suggests the appeal of MWI since it gives enough wiggle room that people think that their free will could control which universe they wind up in, which appeals to everyone's inner Malcolm Gladwell).
I’m currently reading Anathem so this is an interesting topic.
For simplicity, let’s say that all quantum interactions have two possible outcomes, 0 or 1.
The first point is that we can only talk about what interactions appear to have done in the past in our worldline/universe, which is randomly distribute themselves between 0 and 1. If we happened to be on a worldline where all interactions had always resulted in 0 for the whole history of the universe then that universe almost certainly wouldn’t support complex life. So perhaps there’s an observership bias here: if quantum interactions hadn’t decently distributed themselves between 0 and 1 then we wouldn’t be asking this question (just like the values of all the other fundamental constants).
As far as I can tell there’s nothing in current theories which would rule out all future interactions happening to result in a 0. Let’s hope our consciousness don’t end up on that worldline (unless you believe in quantum invulnerability).
But how does bifurcation of consciousness happen and how does it diagonalize the state so that we never see a cat in a complex linear superposition of |alive> and |dead> at the same time? 1/sqrt(2) |alive> + 1/sqrt(2) |dead> should be an equally valid outcome of the experiment via purely unitary evolution.
Consciousness is not a thing that gets bifurcated. It is just a word for an information state that is aware. If you create two information states, you have two awareness states. That is not bifurcation any more than copying a movie and editing one pixel on one frame (or as a better analogy having an effectively infinite number of frames with every possible pixel combination some of which describe aware states).
I don't see how that would allow or require seeing a cat in a complex linear superposition. You just have one set of frames which describe a live cat and another set of frames that describe a dead cat.
I feel like this is a pretty reasonable question being met with non answers. And it's a shame bc I think MWI is the frontrunner as of 2022, but this is a pretty significant question with Many Worlds I had not considered before.
Well I stole it from Roger Penrose (same Penrose as in the title article) which I think he presented in either The Emperor's New Mind or Shadows of the Mind. I think its the latter book which has more concrete arguments like this diagonalization argument. Also, the idea that collapse of the wave function could be mediated by virtual gravitons or something like that once the superposition state got sufficiently "massive" (which is the genesis of the ideas in the title article here).
Both are worthwhile if you like thinking about these kinds of things.
I've generally found nearly zero people who have read those books and of them most people poo-poo it all, and don't really engage with some of the issues presented in them.
He may be wrong. Einstein was also wrong about the EPR paper. But it seems like he's trying to engage with the problems and do science rather than just provide philosophical justification.
The state and result of observation depends on the method of interaction, i.e. hamiltonian. In principle it's possible to observe the cat in a mixed state, we just don't use interaction that gives that result.
Unless I missed something recent, it is not known whether any player has a winning strategy (or a drawing strategy, for that matter). It would be quite the discovery as well.
It would be wild if it turned out that some of the 20 first moves led into a tree that included a perfect winning path for black while others were draw on perfection: "take it, if you can, I bet you can't"
With connect-4 it's like that: playing in the middle on the 1st move means the first player wins, playing adjacent to the middle means the game will be drawn, and starting further to the side means the second player wins (all assuming otherwise perfect play).
Plenty of forced moves in that game, where there is only one option to not lose immediately. I basically sacrificed the last years of school math to a 10x8 variation of that game, it was almost as if there were two competitions in parallel, who would win and who could call a game decided first. Declaring the other guy winner before he even knew was almost better than winning (but certainly not as good as declaring victory and then explaining why)
White could start with a knight move. Unlike Hexapawn, in chess, white moving first provides an increase in optionality for white, and the board positions are not forcing white on some losing track, because white is free to "burn" a move with many pieces by taking 2 moves to get to the same place they could with 1 move. White can use two bishop moves, or a pawn push to the 3rd rank followed by the 4th rank, to turn around the initiative early in the game.
Black doesn't know it's getting two moves in a row when it makes the first move. And on the second move, it can only take advantage if white's first move reduces white's optionality in a specific manner, e.g. by blocking another piece essential for response to a certain tactic, which by construction, would mean it wasn't really an opportunity to transpose the game to hand over the initiative.
The scenario we're positing is that perhaps, in fully-solved chess, white is actually in zugzwang, where every initial move is actually bad for them.
If there were some way for white to hand the first move to black, then clearly this would be the best solution.
But all the take-back solutions (e.g. move the knight forward and back again) actually give black two moves, which is a different situation.
And the stutter-step solution of white moving a pawn only one space instead of two doesn't work because that's simply refuting the premise that white is in zugzwang.
