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location Armenia
age 21
visits member for 3 years, 4 months
seen Aug 21 at 21:34

Aug
11
comment Is there a reason why a relativistic quantum theory of a single fermion exists, but of a single scalar not?
The problem of negative energies appears in both cases, but as I understand it is not really a problem. The modern interpretation of this negative energy states is that they propagate backwards in time, which are equivalent to forward propagating positive energy states - antiparticles.
Jul
15
comment Kaluza Klein theories, dilation field, and dimensional reduction
Can I ask something about this scalar field (dilaton). I read that originally it was just put constant, but I dont see why this is the case. On the other if it has its own dynamics, than how can we fix the radius of extradimension and also wouldnt it affect the other two terms in the action due to its coupling to them? Thanks
Dec
27
comment How to prove the equivalence of two definitions of the scattering cross section
It's my fault, I forgot to mention differential. I'll edit it now.
Dec
27
comment How to prove the equivalence of two definitions of the scattering cross section
As much as I know both are called differential cross sections.
Nov
17
comment Are the Maxwell's equations enough to derive the law of Coulomb?
@Daniel Blay: I guess when you say usual tricks you mean taking a spherical surface around the point charge. The problem for me is that how do we know that the magnitude of the electric field from a point charge is spherically-symmetric. Besides how can we derive that there is no magnetic field (if it is possible to derive from Maxwell's equations)? :)
Nov
17
comment Are the Maxwell's equations enough to derive the law of Coulomb?
@DanilH: I meant 8 scalar equations. From the 4 Maxwell's equations two are vector equations.
Nov
17
comment Are the Maxwell's equations enough to derive the law of Coulomb?
Yes, I have already read this post, but my question is quite different.
Sep
22
comment Deriving the action and the Lagrangian for a free point particle in Special Relativity
Thanks for the answer and for the correct spelling of Lorentz.
May
5
comment The number of independent variables in the Lagrangian and Hamiltonian methods in Classical Mechanics
@Qmechanic : Could you please give the explanation of the Hamiltonian action. Why does it depend on momentum path?
Apr
6
comment The form of Lagrangian for a free particle
OK, now I really understood what was the problem! Thank you very much!