1,457 reputation
725
bio website
location
age
visits member for 4 years, 1 month
seen 13 hours ago

Jul
27
comment Can physics get rid of the continuum?
No, no, Mono, don't take scientific skepticism too serious, it is far not the main engine and essence of science. And the "pragmatic stance" --- it is just an excuse to tell philosophers so they wouldn't bother somebody with questions. It's mostly my beliefs and general agreement with experience (mostly personal) that drive my acception.
Jul
26
comment Can $10^{23}$ stars be treated with methods of statistical mechanics?
@Shaktyai I meant that the system won't be extensive, unlike the gas and I guess the plasma. In plasma you have charges of both sign screening each other and you can do cut-off. If you have $N$ molecules and you add $N$ more nothing changes much, only doubles. But with gravity it's not just doubling. You can divide gas into two parts and they will interact only by their boundary, but gravitating gas would interact in bulk. I don't mean the statistical or hydrodynamic description is impossible (indeed I think it exists and used), I want to say it should differ in certain principal ways.
Jul
25
comment Can $10^{23}$ stars be treated with methods of statistical mechanics?
I hope one will address the fact that $1/r$ in some sense is so different from $1/r^6$, I'm not capable of doing it the proper way.
Jul
25
comment fun computational physics projects
@dmckee MSE seems to be a good home for such questions
Jul
25
comment Can physics get rid of the continuum?
"Why would we assert that such an infinite amount of points "are out there"" Frankly, for me it is sufficient they are in my mind, I can deal with them to a certain extent. I enjoy the beauty of my perception of the world, I don't care if it is wrong provided it doesn't contradict with what I see/know. And I don't see/know if continuum exists in Nature or not.
Jul
25
revised Can physics get rid of the continuum?
added 446 characters in body
Jul
25
answered Can physics get rid of the continuum?
Jul
24
comment Poisson structure comes from hamiltonian?
Sympletic structure arises naturally on the cotangent bundle $T^*Q$ of the configuration space $Q$. Nothing needed, it's already there. Not even Riemannian structure (kinetic energy) on $Q$, $Q$ should be just a smooth manifold. That's the naturallity in math.
Jul
24
comment Hamiltonian and the space-time structure
@Shaktyai "I use to think Hamiltonian was a mere Legendre transform of the lagrangian and that kinetic energy was simply 1/2*mV^2" And why is it 1/2*mV^2?
Jul
24
revised Hamiltonian and the space-time structure
typo
Jul
24
comment Hamiltonian and the space-time structure
What you've done you showed how to derive equations of motion of a free particle given the metrics. Am I right? It is very close to the original question, though the question was asking to find the kinetic energy, not the equations of motion. And by the way, what's your view on how to find $g$ for a system of particles?
Jul
24
revised Hamiltonian and the space-time structure
added 8 characters in body
Jul
23
awarded  Critic
Jul
22
comment What happens to a delta-wing plane when it's nose is tilted away from the line of motion 30 to 45 degrees horizontally?
it can be reformulated to be more general (just replace numbers by letters), but I think it would be a miracle if there is anybody capable of answering the question here. Ian, I bet you know someone in person who could answer it or recommend someone else to help.
Jul
22
comment Hamiltonian and the space-time structure
To make it clearer, you assume that the system moves along geodesics and derive Hamiltonian equations?
Jul
22
answered Units of Distance, Pressure, and Temperature
Jul
22
comment Units of Distance, Pressure, and Temperature
According to wikipedia "Metric system" is quite a vague term (en.wikipedia.org/wiki/Metric_system#Variants). Do you mind using SI? (en.wikipedia.org/wiki/International_System_of_Units)
Jul
22
revised Hamiltonian and the space-time structure
added 2139 characters in body
Jul
22
answered Hamiltonian and the space-time structure
Jul
22
awarded  Yearling