Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A One-Atom Laser in a Regime of Strong Coupling   Although conventional lasers operate with a large number of intracavity
atoms, the lasing properties of a single atom in a resonant cavity have been
theoretically investigated for more than a decade. Here we report the
experimental realization of such a one-atom laser operated in a regime of
strong coupling. Our experiment exploits recent advances in cavity quantum
electrodynamics that allow one atom to be isolated in an optical cavity in a
regime for which one photon is sufficient to saturate the atomic transition. In
this regime the observed characteristics of the atom-cavity system are
qualitatively different from those of the familiar many atom case.
Specifically, we present measurements of intracavity photon number versus pump
intensity that exhibit "thresholdless" behavior, and infer that the output flux
from the cavity mode exceeds that from atomic fluorescence by more than
tenfold. Observations of the second-order intensity correlation function
demonstrate that our one-atom laser generates manifestly nonclassical light
that exhibits both photon antibunching and sub-Poissonian photon statistics.

30
The categories of this paper are: q-alg
31
The categories of this paper are: ao-sci
17
The categories of this paper are: q-fin
0
The categories of this paper are: hep-ph
27
The categories of this paper are: comp-gas
26
The categories of this paper are: bayes-an
11
The categories of this paper are: hep-lat
1
The categories of this paper are: cs
8
The categories of this paper are: hep-ex
20
The categories of this paper are: acc-phys
18
The categories of this paper are: econ
22
The categories of this paper are: chao-dyn
14
The categories of this paper are: math-ph
37
The categories of this paper are: supr-con
32
The categories of this paper are: atom-ph
3
The categories of this paper are: physics