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location New York City
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visits member for 3 years, 4 months
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I do not participate on this site any longer, except to respond to comments regarding my own text, if that text is unavailable in another form. I do not accept the political moderation atmosphere here, it is not compatible with open science. I participate at physicsoverflow.org.


Aug
15
answered Do all massive bodies emit Hawking radiation?
Aug
15
comment Do all massive bodies emit Hawking radiation?
The charged particle in free fall most certainly does radiate!!
Aug
15
comment What potential energy functions are mostly used in Schrodinger equation?
I added some entry points. The basic theoretical results are that all the energy eigenstates in one and two dimensions with an arbitrarily small random potential decay exponentially at long distances. In three dimensions and higher, there is a phase transition as you vary the strength of the randomness between localized and extended wavefunctions. There is very little known rigorously, as far as I know, but a huge amount known by physics standards of certainty. I added a few very old literature pointers in the answer itself.
Aug
15
revised What potential energy functions are mostly used in Schrodinger equation?
add literature entry points
Aug
14
awarded  Revival
Aug
14
revised Where do the choice of basis in QFT come from?
not markup
Aug
14
answered Where do the choice of basis in QFT come from?
Aug
14
answered What potential energy functions are mostly used in Schrodinger equation?
Aug
14
revised Did Einstein prove $E=mc^2$ correctly?
shorten, remove wikipedia-isms
Aug
14
answered Did Einstein prove $E=mc^2$ correctly?
Aug
14
comment Is this geometrical 'derivation' of Brownian motion legitimate?
I just wanted to add that in mathematics, a process which doesn't go anywhere on average is called a martingale, and this is called the martingale derivation of the sqrt(N) law. I think Levy of Levy flight fame did things like this.
Aug
14
answered Entropy of an empty universe
Aug
14
comment Why is there an absolute entropy?
This is correct, but I think it should be expanded to say that the entropy becomes a number because quantum states in finite volume/energy are discrete, so there is a number of them. In infinite volume, they become extensive but without the fine-graining classical ambiguity.
Aug
14
comment The entropic cost of tying knots in polymers
The unknot is only entropically favorable for short polymers, where you can calculate the entropy brute force, by simulating. For the long polymer limit, where you need a scaling analysis, the unknot would be unlikely. I was going to think about an answer in the long skinny polymer limit.
Aug
14
revised What does it mean that the neutral pion is a mixture of quarks?
explain why this works pretty well
Aug
14
answered What does it mean that the neutral pion is a mixture of quarks?
Aug
14
answered Why do we have so many dualities in string theory?
Aug
14
comment In quantum mechanics, given certain energy spectrum can one generate the corresponding potential?
@Marty--- the question is not physics, it is mathematics--- can you find Schrodinger operators with identical spectrum. This is a trivial example. More trivial examples are any potential and its translates and reflections, and a less trivial example is any potential and its supersymmetric conjugate, when the ground state doesn't break supersymmetry.
Aug
14
revised In quantum mechanics, given certain energy spectrum can one generate the corresponding potential?
oops
Aug
14
revised In quantum mechanics, given certain energy spectrum can one generate the corresponding potential?
added 174 characters in body