Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Thermal Casimir effect for the scalar field in flat spacetime under a
  helix boundary condition   In this work we consider the generalized zeta function method to obtain
temperature corrections to the vacuum (Casimir) energy density, at zero
temperature, associated with quantum vacuum fluctuations of a scalar field
subjected to a helix boundary condition and whose modes propagate in
(3+1)-dimensional Euclidean spacetime. We find closed and analytical
expressions for both the two-point heat kernel function and free energy density
in the massive and massless scalar field cases. In particular, for the massless
scalar field case, we also calculate the thermodynamics quantities internal
energy density and entropy density, with their corresponding high- and
low-temperature limits. We show that the temperature correction term in the
free energy density must suffer a finite renormalization, by subtracting the
scalar thermal blackbody radiation contribution, in order to provide the
correct classical limit at high temperatures. We check that, at low
temperature, the entropy density vanishes as the temperature goes to zero, in
accordance with the third law of thermodynamics. We also point out that, at low
temperatures, the dominant term in the free energy and internal energy
densities is the vacuum energy density at zero temperature. Finally, we also
show that the pressure obeys an equation of state.

14
The categories of this paper are: math-ph
22
The categories of this paper are: chao-dyn
17
The categories of this paper are: q-fin
3
The categories of this paper are: physics
2
The categories of this paper are: math
1
The categories of this paper are: cs
29
The categories of this paper are: funct-an
26
The categories of this paper are: bayes-an
0
The categories of this paper are: hep-ph
4
The categories of this paper are: cond-mat
24
The categories of this paper are: dg-ga
23
The categories of this paper are: solv-int
36
The categories of this paper are: cmp-lg
28
The categories of this paper are: alg-geom
32
The categories of this paper are: atom-ph
18
The categories of this paper are: econ