Peter Shor

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bio	website	math.mit.edu/~shor
	location	Cambridge, MA
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visits	member for	2 years, 6 months
	seen	4 hours ago
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	4,245 reputation	bio	website	math.mit.edu/~shor	visits	member for	2 years, 6 months
924 badges		location	Cambridge, MA		seen	4 hours ago

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2d	comment	fast quantum random number generator + limited decoherence rate => Schrödinger cat state? Why do you think the question about feasibility of macroscopic coherent states is still not settled? References?
May 20	comment	Is the 125 GeV Higgs boson some kind of a “almost-commutative graviton” at the electroweak scale? It is hard figuring out what your actual question is.
May 20	comment	Intuition contradicting answer for calculating pressure Your equations are implicitly assuming that the pressure differences are the force that is accelerating the cylinder.
May 20	comment	Intuition contradicting answer for calculating pressure The cylinder is being accelerated. This means that there is a net force on it.
May 12	comment	Theoretical physics and education: Does it really matter a great deal about what happens inside a black hole, or about Hawking radiation? A little research: John Horgan was a science journalist who won the American Association for the Advancement of Science Journalism Award and was a senior editor at Scientific American before he wrote the very provocative book The End of Science (he has already been proven completely wrong about "The End of Cosmology"). Probably the reason that Scientific American lets him host a blog is that he was a very good science editor for them for 10 years.
May 12	comment	Theoretical physics and education: Does it really matter a great deal about what happens inside a black hole, or about Hawking radiation? Johannes: that's a very good question. John Horgan is a science journalist, and I think he may have been a decent one before he (a) went off the deep end or (b) realized that if he was "provocative" he would get a lot more attention and make more money. And finally, I don't know whether Scientific American is really dedicated to disseminating science (like they used to be) or whether they are more dedicated to providing entertainment and making money?
May 12	comment	Theoretical physics and education: Does it really matter a great deal about what happens inside a black hole, or about Hawking radiation? @Dilaton: You can believe whatever you want, but I don't believe the Scientific American editors censor their bloggers' posts.
May 12	comment	Theoretical physics and education: Does it really matter a great deal about what happens inside a black hole, or about Hawking radiation? @Dilaton: this is a blog, not an article. It should be pretty clear that this is John Horgan's own opinion, and not a viewpoint endorsed by the editors of Scientific American.
May 12	comment	Theoretical physics and education: Does it really matter a great deal about what happens inside a black hole, or about Hawking radiation? Your answer is now greatly improved, since you're not attributing views to John Horgan that he never expressed in his blog post.
May 12	comment	Theoretical physics and education: Does it really matter a great deal about what happens inside a black hole, or about Hawking radiation? -1 for giving an answer without actually reading the link you're commenting on. John Horgan never mentions black hole thermodynamics in his blog post. The actual example he gives is the question: "what happened before the Big Bang?" While I disagree with John Horgan on lots of stuff, I see no evidence to believe he doubts the relevance of black hole thermodynamics.
May 12	comment	Theoretical physics and education: Does it really matter a great deal about what happens inside a black hole, or about Hawking radiation? "Why not wait to make predictions, until we're somewhat close to being able to test them?" Bose-Einstein condensation was predicted in 1925, and first observed in 1995. There was absolutely no reason to wait to make this prediction. In fact, the prediction of Bose-Einstein condensation told physicists a lot about the nature of quantum mechanics, helped explain superconductivity and superfluidity, and eventually set up an experimental race to be the first to find this phenomenon.
May 12	comment	Why is $r'/r^2 = -1/r$? You're missing a derivative on the right-hand-side of your equation. The equation you saw was likely $ \frac{r'(t)}{(r(t)^2)} = - \left(\frac{1}{r(t)}\right)'$.
May 6	comment	What is the difference between lattice vectors and basis vectors? The OP is talking about crystallography. In this context, basis vectors don't have to be orthogonal.
May 6	comment	What is the real-world significance of the Bekenstein bound? Note the size of a hydrogen atom in the $2^{1000000}$th state is much, much larger than the size of a hydrogen atom in the ground state, so the Bekenstein bound holds.
May 2	comment	Is the “particle number” of “electrons” well defined in Wen's string-net theory of elementary particles? Charge is conserved, but the number of electrons isn't. This is true both in Wen's theory and (so far as we know) in the actual universe. In Wen's theory, every particle has an antiparticle (which might be itself) and you can always create a particle-antiparticle pair out of the vacuum.
Apr 27	comment	Some questions about anyons? This paper of Beni Yoshida proves theorems about a broad class of 2- and 3-dimensional generalizations of Kitaev's toric code. You may also want to look at the citations for earlier papers about these models. There are also a few papers about more general codes (corresponding to non-abelian anyons), but I can't easily locate these right now.
Apr 27	comment	Some questions about anyons? Regarding your last point, there are indeed generalizations of Kitaev's toric code model with pointlike and stringlike quasiparticles.
Apr 25	comment	Interference and which-path information @Rococo: I think that this idea isn't relevant in this case, because the photons are entangled, even though it is a very important piece of understanding quantum mechanics when there isn't entanglement. So I think your answer is incorrect. This is a fairly subtle point which isn't intuitive, and when I get some time, I may try to think of a good way of explaining this and post it as an answer.
Apr 24	comment	What is the current state of research in quantum gravity? I don't know whether you can call this progress, but the AMPS paper shows that there are significant problems with the "complementarity" idea for resolving the black hole information paradox (which Carlip's paper calls "not very convincing," along with the rest of the ideas for a resolution).
Apr 24	comment	Interference and which-path information -1 for your sentence: " Whether the wall preserves this information or not depends on its specific properties, but generically it would not." Quantum mechanics is unitary, which means that orthogonal states are taken to orthogonal states. Thus, the wall must preserve the information, no matter how you carefully you design it so as not to. In the quantum eraser experiment, the interference only becomes visible after conditioning on the results of a measurement on the idler photon which has been designed to destroy the which-way information.