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seen Feb 13 at 14:36

Feb
10
answered Is it possible to escape from within event horizon?
Feb
10
answered Does the speed of light in different mediums affect the lorentz transformation?
Feb
10
comment Spin version of Maxwell's demon: Where's the energy?
Thanks. I don't normally think of spin chains. I'd have expected the size of correlated regions to go to infinity with T to zero. In any case, the only thing that matters is that heating up the state means its total energy increases, but increases in a 'useless' way. I don't know how the total change of spin induced by a photon can even be zero. You're right in that I missed a factor two. Be that as it may, nothing of that solves my problem :(
Feb
8
asked Spin version of Maxwell's demon: Where's the energy?
Feb
8
comment Free Will Theorem question
Oh, it does have something to do with free will. Free will is a central assumption to the conclusions that they make. I agree though that the name is unfortunate because you can't actually conclude anything about something that you've just assumed to exist.
Feb
8
comment How to reconcile these two principles?
Look up the definition of "entanglement entropy": dividing space into different sections (as eg a horizon does) creates an entropy that is proportional to the surface area, even though the total entropy is zero.
Feb
8
answered Vacuum energy: black hole evaporation and cosmology - a discrepancy?
Feb
8
answered Why don't X-rays/Gamma rays ionize all the atoms at the surface of a material?
Jan
19
awarded  Yearling
Jan
6
comment Moving Between Degenerate Vacua?
Well, if you just look at the energy of the state, of course the axis of magnetization can change because these states have the same energy. But the fluctuation around the ground state required for this is highly correlated, I guess the probability for this to happen is essentially nil.
Jan
6
comment Moving Between Degenerate Vacua?
No, sorry, I still don't get your problem. Everything in the valley is stable in the same way. If you want to call different points in the valley 'different vacua' (it's technically correct I think, but operationally meaningless) then the statement that the 'vacuum is not stable if it can jump from one vacuum to another' is wrong.
Jan
6
comment Does the spinning of a nucleus alter its charge distribution?
dmckee: But that is exactly my question. Do you have a reference? What happens in a magnetic field?
Jan
5
comment Does the spinning of a nucleus alter its charge distribution?
I know that nuclei can deform. I am asking if the electric charge distribution remains homogeneous.
Jan
5
comment Why does a wavefunction collapse when observation takes place?
This one I found pretty useful arxiv.org/abs/quant-ph/0505070
Jan
5
comment Why does a wavefunction collapse when observation takes place?
I have a reference... somewhere. Will try to find it.
Jan
5
answered Moving Between Degenerate Vacua?
Jan
4
awarded  Custodian
Jan
4
reviewed Approve suggested edit on Does the spinning of a nucleus alter its charge distribution?
Jan
4
answered Why does a wavefunction collapse when observation takes place?
Jan
4
asked Does the spinning of a nucleus alter its charge distribution?