Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Thermal Casimir vs Casimir-Polder forces: Equilibrium and
  non-equilibrium forces   We critically discuss the common belief that the thermal Casimir-Polder force
can always be represented as a Matsubara sum, as it is true for the Casimir
force. On the contrary, an exact treatment of the atom-field coupling reveals
that for a ground-state atom, terms associated with virtual-photon absorption
contribute to the force which are identified as a signature of non-equilibrium
dynamics. Even the equilibrium force on a thermalized atom or molecule may be
overestimated when using the ground-state polarizability instead of its thermal
counterpart.

36
The categories of this paper are: cmp-lg
10
The categories of this paper are: q-bio
3
The categories of this paper are: physics
26
The categories of this paper are: bayes-an
31
The categories of this paper are: ao-sci
35
The categories of this paper are: mtrl-th
11
The categories of this paper are: hep-lat
37
The categories of this paper are: supr-con
28
The categories of this paper are: alg-geom
12
The categories of this paper are: nucl-th
6
The categories of this paper are: astro-ph
23
The categories of this paper are: solv-int
22
The categories of this paper are: chao-dyn
25
The categories of this paper are: patt-sol
34
The categories of this paper are: chem-ph
16
The categories of this paper are: stat