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"I would never die for my beliefs because I might be wrong."

-- Bertrand Russell


Dec
2
answered CPT and heat equation
Dec
1
comment How many Onsager's solutions are there?
Yeah, I kinda got that was what you were looking after, the technique to arrive at the solution rather than just the solution itself. Maybe you should put a bounty on the question to attract people. :p
Dec
1
comment How many Onsager's solutions are there?
Seems to me the differences are just in the techniques. The solution of the system should remain the same, and that's why they call it Onsager's solution, while there are many different ways to arrive at it. Quite typical of physics problems no? Wether you solve the Kepler problem with Newtonian mechanics or Hamiltonian mechanics, the solution is the same. However, a new insight can be coupled to the different technique. Or one of the techniques can be more easily generalizable. If nobody comes along with a ready answer, I'm willing to look a bit more deeply into this.
Dec
1
revised Ising model for dummies
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Dec
1
revised Ising model for dummies
added 297 characters in body
Dec
1
comment Ising model for dummies
I found some books I used back in the day when I had to do an undergrad project about the subject. I can't remember what book was most useful, but I'll just add the ones I think are relevant. Note, they are pretty old, so there might be some recent books with nicer approaches.
Dec
1
answered Ising model for dummies
Dec
1
comment Light emission spectrum units
It doesn't specify in what units the numbers in the other files are. But I suppose knowing the apparatus that did the measurement can help resolve that issue.
Dec
1
comment What's with the very slightly larger mass of the neutron compared to the proton?
Sadly, they can not yet differentiate between proton and neutron. But it's a great achievement nonetheless.
Dec
1
comment What is an analog to QM's Hilbert space in GR?
You are really obsessed with this perfect fluid history, aren't you? I'm sorry but I can't tell you, that's outside of my expertise. It seems to me you should talk to some astrophysicist doing simulations of things like galaxies. That's typically the kind of field where people worry about such questions. Try to ask a question which has this explicitly in the topic title, maybe you'll get an expert to reply. +1 for Marek, exactly my thought. ;)
Dec
1
comment What is an analog to QM's Hilbert space in GR?
Depends how smooth you want it. Generally, for the equations to make sense, you only need existance of the second derivative. But I guess stronger assumptions of smoothness are made depending on what problems one wants to tackle.
Dec
1
revised What is an analog to QM's Hilbert space in GR?
added 162 characters in body
Dec
1
comment What is an analog to QM's Hilbert space in GR?
No, it's not a typo, but I admit I have not been clear enough. $N$ is the amount of particles you want to describe. You multiply by 6 because each particle has 3 spatial coordinates and 3 momenta along each spatial direction. The structure of phase space is that of a symplectic manifold.
Dec
1
answered What is an analog to QM's Hilbert space in GR?
Nov
30
comment Is there a conserved quantity that enforces planar orbits in central force motion?
Wait, isn't that precisely the angular momentum? You just said angular momentum has to be constant before that, so I assumed you already figured it out. I do know there is a Laplace-Runge-Lenz vector, but if I remember correctly, that one is associated to the ellipticity of the trajectory.
Nov
30
comment Why is the mapped universe shaped like an hourglass?
Actually, filtering the radiation of the galaxy from the CMB is a difficult task. Look at these images from COBE. Look at the equivalent picture but now taken by WMAP. You see there's always a red horizontal band in the middle. That's the galaxy, and they have to filter it out somehow.
Nov
30
answered Why is the mapped universe shaped like an hourglass?
Nov
30
comment How far does a trampoline vertically deform based on the mass of the object?
To be fair, the OP really asks about dynamics. But I agree that starting with explaining the static case can not hurt.
Nov
29
revised Reciprocal Lattices
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Nov
29
answered Reciprocal Lattices