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I'm Scott Aaronson, quantum computing/computational complexity researcher. AMA

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Re: I'm Scott Aaronson, quantum computing/computational complexity researcher. AMA

#111

Post by ScottAaronson »

algon33 wrote: post #101

Hi Scott, Do you think that chaotic systems would be better analysed by quantum computing over classical computing? More generally, is BQP powerful enough to deal with chaotic systems in the same way P is for linear systems? Oh, and I think your review of "Enlightenment Now" was a bit too rosy. When he analysed the data he's superb, but he seems to lambast people he heavily disagrees with. Its a tad disheartening.

No, I don't think that QCs will help much for simulating chaotic systems, except insofar as those systems are also quantum-mechanical. For (e.g.) predicting the weather, there may be small quantum speedups that you can get here and there, from Grover's algorithm and faster gradient computation and so forth, but at a fundamental level, as far as anyone knows, you still need to just iterate the partial differential equation from one time step to the next, same as a classical computer does.

Stepping back, note that "quantum" and "nonlinear" are two completely different concepts -- in fact, at the level of amplitudes (i.e., the Schrodinger equation), quantum mechanics is the one example we have in physics of a perfectly LINEAR theory! Alan Sokal had a lot of fun with that point in his "Social Text" parody article: http://www.physics.nyu.edu/sokal/transgress_v2/transgress_v2...

On the other hand, this is perfectly compatible with quantum systems having chaotic phenomena at the level of observables (like the positions and momenta of particles), and in fact there's a whole field called "quantum chaos" that studies such situations.

Re: I'm Scott Aaronson, quantum computing/computational complexity researcher. AMA

#112

Post by phs »

ScottAaronson wrote: post #105
OscarCunningham wrote: post #61

How do you feel about the Axiom of Choice?

It feels really uncomfortable that, if you have infinitely many people wearing red or blue hats that they can't see, then they can all guess their own hat color with only finitely many of them being wrong. Not to mention Banach-Tarski and a hundred other strange phenomena. This all militates toward rejecting AC. But then, if we reject AC, we can have infinite sets that are incomparable (i.e., they're not isomorphic a…

As a follow-up, what is your position on intuitionist/constructivist logic?

Re: I'm Scott Aaronson, quantum computing/computational complexity researcher. AMA

#113

Post by JakeTyo »

martin1975 wrote: post #99
ScottAaronson wrote: post #88

Earlier quoted context omitted.

My position on the technical fundamentals never changed much: namely, D-Wave is building devices that could be interesting from various engineering perspectives, but that as far as most of us can tell, are not getting speedups over existing computers that are clearly attributable to quantum computation (as opposed to building special-purpose hardware that's, essentially, very fast at simulating itself). If you want q…

Am I hearing this right, you think the whole multiverse concept is... meta-physics at best?

You simply can't something 'physics' if its not testable. :)

Re: I'm Scott Aaronson, quantum computing/computational complexity researcher. AMA

#114

Post by Y_Y »

schoen wrote: post #70
Y_Y wrote: post #52

Hi Scott, Why do we live in a universe where the Halting Problem is unsolvable?

(Not Scott!) The Halting Problem's unsolvability is proven in a fully abstract mathematical way, and so the truth of this result is as logically necessary as the truth of other mathematical theorems. It doesn't refer to anything about physics. So it seems like this question might be better bifurcated into Why do we live in a world in which Turing machines are a good model for what computations we can physically perfo…

Who said anything about physics? I was thinking about axioms/logic systems and finitism.

Re: I'm Scott Aaronson, quantum computing/computational complexity researcher. AMA

#115

Post by geraltofrivia »

Hi Scott, I got interested in Quantum Computing, and fundamental mathematics a week ago. Ever since, I'm reading your book `Quantum Computing since Democritus`. I discovered your blog (oh and it's such a joy to read!). Today I run into your podcasts and AMA. This is going to get overwhelming very soon, I feel.

Couple things: your book is an amazing repertoire of abstractions, theorems, phenomenon and whatnots. Does it get overwhelming sometimes walking down the street like normal people, with that deep an understanding of these domains?

I personally think that your book is a nice place to start with, in the domain(s) of fundamental mathematics. The text gives a nice idea of the depth I'll encounter in these fields (I think). Keepin' it real helps me, an engineering grad, to not pass it up as ravings of men with too much time on their hands. Do you think your book should be read in this context? What else would you recommend, if any?

Re: I'm Scott Aaronson, quantum computing/computational complexity researcher. AMA

#116

Post by denimalpaca »

I took a grad-level quantum computing class which I didn't quite have the physics background for, and the lecture that lost me, about 3 weeks in, was on the different kinds of physical gates quantum computers use.

My recollection is that there were 3 necessary gates for a quantum functionally complete set: One gate was classically functionally complete, the other two are where I got lost. Can you explain like I'm 5 (or explain like I'm an undergrad with minimal QM knowledge) what these other gates are doing?

Thanks!

Re: I'm Scott Aaronson, quantum computing/computational complexity researcher. AMA

#117

Post by taserian »

Hiya, Scott! I recently heard the first episode of Rationally Speaking podcast episode where you were the guest (yes, I'm catching up with the RS Archives during my long commute). I've also started reading QCSD (hey, if it's going to be our decade's GEB, we may as well give it an acronym. :: grin:: )

I've already corrected my very mistaken understanding of how QC works, as in the tagline of your blog. Are there any other concepts that we need to shake off that would make explaining these concepts easier for the layman? Do you have any words of wisdom for the masses?

Re: I'm Scott Aaronson, quantum computing/computational complexity researcher. AMA

#119

Post by _0w8t »

Hi Scott,

If somebody claims that there is no freedom of will, what what you accept as a reasonable proof? It seems that one can be sceptical even in presence of extremely precize predictions as it my be easier to alter memory about predictions than to produce them.

Re: I'm Scott Aaronson, quantum computing/computational complexity researcher. AMA

#120

Post by red75prime »

defen wrote: post #102
ScottAaronson wrote: post #88

Earlier quoted context omitted.

My position on the technical fundamentals never changed much: namely, D-Wave is building devices that could be interesting from various engineering perspectives, but that as far as most of us can tell, are not getting speedups over existing computers that are clearly attributable to quantum computation (as opposed to building special-purpose hardware that's, essentially, very fast at simulating itself). If you want q…

Another problem with the quantum suicide thought experiment is that there are plenty of branches where you end up alive but horribly disabled.

Yet another problem with that is no matter how small the measure of those branches is, you'll end up in them anyway.

The death of natural causes qualifies too.

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