1,378 reputation
525
bio website
location
age
visits member for 3 years, 11 months
seen Dec 20 at 20:33

I am an engineer learning physics in my spare time. My current focus is quantum field theory and the Standard Model.


Dec
20
comment How do creation operators change with time in an interacting theory?
That was a mistake on my part, I thought it was automatically awarded.
Dec
19
accepted How do creation operators change with time in an interacting theory?
Dec
16
comment How do creation operators change with time in an interacting theory?
@DanielSank as far as I am concerned, this is not overkill. But I would also like to see a qualitative discussion on how the operators differ.
Dec
15
comment How do creation operators change with time in an interacting theory?
I have seen this derivation in textbooks indeed, but the physical meaning eludes me. Do the operators vary in norm, or in phase ? What is the difference between the asymptotic states created ?
Dec
15
comment Is it possible to assign a physical radius to a black hole?
If we do that for the horizon, the line element reduces to $r_S^2d\theta^2$, so that makes it the same as saying that the radius is equal to the Schwarzschild radius?
Dec
15
asked Is it possible to assign a physical radius to a black hole?
Dec
15
answered Can a quantum field be understood as a superposition of all particles' wave functions?
Dec
12
asked How do creation operators change with time in an interacting theory?
Dec
10
awarded  Nice Question
Nov
27
answered Entropy change in irreversible heat flow
Nov
12
awarded  Popular Question
Nov
6
comment How do we measure pressure above a liquid column?
Pascal's law means that the pressure force on any elementary surface is independent of the direction of the surface. It does not means that the pressure can not vary from point to point.
Nov
6
comment Can energy be created and destroyed?
This answer uses vague language such as 'external energy working against the field' and is difficult to make sense of. You should consider clarifying your thought.
Nov
5
answered Applications of statistical mechanics
Nov
5
answered Entropy of ideal gas with finite volume
Nov
5
answered Comparison between entropy and internal energy
Nov
4
answered Second Law from Statistics
Nov
3
answered Gravity and Magnetism… One and the same?
Oct
21
comment Why can we say that $\bar{d}Q=TdS$?
In non-equilibrium thermodynamics, one common assumption is that of local thermodynamic equilibrium, where each infinitesimal cell in the medium is assumed to be approximated by an equilibrium state, even though there is no equilibrium at the larger scale. The addition of Onsager relations then allows for a description of how those local states interact and evolve.
Oct
21
comment Why can we say that $\bar{d}Q=TdS$?
This equation is one form of the fundemental thermodynamic equation. It is valid between equilibrium states. That is because quantities such as $U$ or $T$ are not well defined for non-equilibrium states, since there is no statistical ensemble associated with those states. However, it is often possible to have quasi-equilibrium states that are closely approximated by equilibrium states for which thoese quantities are well defined. This is why those thermodynamic relations can be broadly applied.