Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: How to mode-lock an atom laser   We consider a possible technique for mode-locking an atom laser, based on the
generation of a dark soliton in a ring-shaped Bose-Einstein condensate, with
repulsive atomic interactions. The soliton is a kink, with angular momentum per
particle equal to \hbar/2. It emerges naturally, when the condensate is stirred
at the soliton velocity, and subsequently outcoupled with a periodic Raman
pulse-train. The result is a replicating coherent field inside the atom laser.
We give a numerical demonstration of the generation and stabilization of the
soliton.

16
The categories of this paper are: stat
11
The categories of this paper are: hep-lat
36
The categories of this paper are: cmp-lg
1
The categories of this paper are: cs
12
The categories of this paper are: nucl-th
33
The categories of this paper are: plasm-ph
0
The categories of this paper are: hep-ph
34
The categories of this paper are: chem-ph
29
The categories of this paper are: funct-an
20
The categories of this paper are: acc-phys
9
The categories of this paper are: nlin
2
The categories of this paper are: math
14
The categories of this paper are: math-ph
7
The categories of this paper are: hep-th
27
The categories of this paper are: comp-gas
5
The categories of this paper are: gr-qc