Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Structure and stability of two-dimensional Bose-Einstein condensates
  under both harmonic and lattice confinement   In this work, we study pancake-shaped Bose-Einstein condensates confined by
both a cylindrically symmetric harmonic potential and an optical lattice with
equal periodicity in two orthogonal directions. We first identify the spectrum
of the underlying two-dimensional linear problem through multiple-scale
techniques. Then, we use the results obtained in the linear limit as a starting
point for a nonlinear existence and stability analysis of the lowest energy
states, emanating from the linear ones, in the nonlinear problem. Two-parameter
continuations of these states are performed for increasing nonlinearity and
optical lattice strengths, and their instabilities and temporal evolution are
investigated. It is found that the ground state as well as one of the excited
states are either stable or weakly unstable for both attractive and repulsive
interatomic interactions.

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The categories of this paper are: hep-ph
30
The categories of this paper are: q-alg
34
The categories of this paper are: chem-ph
3
The categories of this paper are: physics
14
The categories of this paper are: math-ph
18
The categories of this paper are: econ
36
The categories of this paper are: cmp-lg
37
The categories of this paper are: supr-con
17
The categories of this paper are: q-fin
33
The categories of this paper are: plasm-ph
19
The categories of this paper are: eess
22
The categories of this paper are: chao-dyn
13
The categories of this paper are: quant-ph
21
The categories of this paper are: adap-org
25
The categories of this paper are: patt-sol
4
The categories of this paper are: cond-mat