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May
14
awarded  Nice Question
May
10
awarded  Good Question
Apr
14
awarded  Popular Question
Jan
28
awarded  Yearling
Nov
24
accepted How can we be sure that nature isn't “faking” quantum statistics?
Nov
15
asked How can we be sure that nature isn't “faking” quantum statistics?
Nov
14
comment How can it be that the beginning universe had a high temperature and a low entropy at the same time?
@Mike Dunlavey Do you want to say that it is possible to reach zero entropy without having zero temperature?
Nov
14
comment How can it be that the beginning universe had a high temperature and a low entropy at the same time?
@Mike Dunlavey "Absolute zero is the theoretical temperature at which entropy reaches its minimum value" is the first sentence in en.wikipedia.org/wiki/Absolute_zero
Nov
12
awarded  Nice Question
Sep
23
answered Common false beliefs in Physics
Aug
26
asked How can it be that the beginning universe had a high temperature and a low entropy at the same time?
Jul
17
comment Is there a relativistic generalization of the Maxwell-Boltzmann velocity distribution?
I believe this ansatz has a problem even for speeds below c. If $E_{kin} = (\gamma-1)m c^2 > 2 m c^2 $ that is for $v > \frac{2}{3} \sqrt{2} c = 0.94c$ the energy is enough for pair production. I guess at this point a distribution based on a constant number of particles cannot be correct, am I right?
Jul
16
accepted How to derive the Karman-Howarth-Monin relation for anisotropic turbulence?
Jul
16
accepted Is the fine structure constant actually a constant or does its value depend on the energy scale?
Jul
16
asked Is there a relativistic generalization of the Maxwell-Boltzmann velocity distribution?
Jul
16
awarded  Teacher
Jul
16
answered Can Maxwell's equations be derived from Coulomb's Law and Special Relativity?
Jun
16
comment Is the fine structure constant actually a constant or does its value depend on the energy scale?
@Marek Isn't it purely for historical reasons that the Planck units are set to one in QFT and thereby classified as fundamental? One could also use en.wikipedia.org/wiki/Stoney_units and then $\hbar$ wouldn't be fundamental. Isn't the differentiation between fundamental constants and non-fundamental constants completely arbitrary?
Jun
16
comment Is the fine structure constant actually a constant or does its value depend on the energy scale?
@Marek and @Qmechanic: Your arguments why $\varepsilon_0$ cannot change with energy seem to boil down to the argument that one wants the speed of light $c$ not to change with energy to not break Lorentz invariance. Am I right? But what about Planck's constant? Couldn't one instead of rescaling $e$ rescale $\hbar$ with energy and achieve the same result of a running $\alpha$ with energy?
Jun
15
comment Is the fine structure constant actually a constant or does its value depend on the energy scale?
But why can't we say $\varepsilon_0$ changes with energy scale? I could argue that due to the interaction of the virtual particles with the charge the vacuum permittivity changes locally near that charge and that's why the coupling changes with energy. What are the observed symmetries we want to preserve at all scales that force us to vary the elementary charge with energy?