Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Negative spontaneous emission by a moving two-level atom   In this paper we investigate how the dynamics of a two-level atom is affected
by its interaction with the quantized near field of a plasmonic slab in
relative motion. We demonstrate that for small separation distances and a
relative velocity greater than a certain threshold, this interaction can lead
to a population inversion, such that the probability of the excited state
exceeds the probability of the ground state, corresponding to a negative
spontaneous emission rate. It is shown that the developed theory is intimately
related to a classical problem. The problem of quantum friction is analyzed and
the differences with respect to the corresponding classical effect are
highlighted.

10
The categories of this paper are: q-bio
27
The categories of this paper are: comp-gas
34
The categories of this paper are: chem-ph
9
The categories of this paper are: nlin
23
The categories of this paper are: solv-int
37
The categories of this paper are: supr-con
29
The categories of this paper are: funct-an
33
The categories of this paper are: plasm-ph
1
The categories of this paper are: cs
32
The categories of this paper are: atom-ph
4
The categories of this paper are: cond-mat
20
The categories of this paper are: acc-phys
35
The categories of this paper are: mtrl-th
5
The categories of this paper are: gr-qc
11
The categories of this paper are: hep-lat
7
The categories of this paper are: hep-th