Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Non-equilibrium states of a photon cavity pumped by an atomic beam   We consider a beam of two-level randomly excited atoms that pass one-by-one
through a one-mode cavity. We show that in the case of an ideal cavity, i.e. no
leaking of photons from the cavity, the pumping by the beam leads to an
unlimited increase in the photon number in the cavity. We derive an expression
for the mean photon number for all times. Taking into account leaking of the
cavity, we prove that the mean photon number in the cavity stabilizes in time.
The limiting state of the cavity in this case exists and it is independent of
the initial state. We calculate the characteristic functional of this
non-quasi-free non-equilibrium state. We also calculate the energy flux in both
the ideal and open cavity and the entropy production for the ideal cavity.

15
The categories of this paper are: nucl-ex
28
The categories of this paper are: alg-geom
11
The categories of this paper are: hep-lat
34
The categories of this paper are: chem-ph
1
The categories of this paper are: cs
5
The categories of this paper are: gr-qc
20
The categories of this paper are: acc-phys
22
The categories of this paper are: chao-dyn
16
The categories of this paper are: stat
35
The categories of this paper are: mtrl-th
0
The categories of this paper are: hep-ph
33
The categories of this paper are: plasm-ph
12
The categories of this paper are: nucl-th
32
The categories of this paper are: atom-ph
27
The categories of this paper are: comp-gas
36
The categories of this paper are: cmp-lg