Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Rotating Bose gas with hard-core repulsion in a quasi-2D harmonic trap:
  vortices in BEC   We consider a gas of N(=6, 10, 15) Bose particles with hard-core repulsion,
contained in a quasi-2D harmonic trap and subjected to an overall angular
velocity $\Omega$ about the z-axis. Exact diagonalization of the $n\times n$
many-body Hamiltonian matrix in given subspaces of the total (quantized)
angular momentum L$_{z}$, with $n\sim 10^{5}$(e.g. for L$_{z}$=N=15, n =240782)
was carried out using Davidson's algorithm. The many-body variational ground
state wavefunction, as also the corresponding energy and the reduced
one-particle density-matrix were calculated. With the usual identification of
$\Omega$ as the Lagrange multiplier associated with L$_{z}$ for a rotating
system, the $L_{z}-\Omega$ phase diagram (or the stability line) was determined
that gave a number of critical angular velocities $\Omega_{{\bf c}i},
i=1,2,3,... ,$ at which the ground state angular momentum and the associated
condensate fraction undergo abrupt jumps.
  A number of (total) angular momentum states were found to be stable at
successively higher critical angular velocities $\Omega_{{\bf c}i}, \
i=1,2,3,...$ for a given N. For $L_{z}>N$, the condensate was strongly
depleted. The critical $\Omega_{{\bf c}i}$ values, however, decreased with
increasing interaction strength as well as the particle number, and were
systematically greater than the non-variational Yrast-state values for the
single vortex state with L$_{z}$ =N. We have also observed that the condensate
fraction for the single vortex state (as also for the higher vortex states) did
not change significantly even as the 2-body interaction strength was varied
over several $(\sim 4)$ orders of magnitude in the moderately to the weakly
interacting regime.

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The categories of this paper are: dg-ga
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The categories of this paper are: comp-gas
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The categories of this paper are: nlin
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The categories of this paper are: chao-dyn
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The categories of this paper are: adap-org
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The categories of this paper are: solv-int
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The categories of this paper are: astro-ph
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The categories of this paper are: chem-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: math-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: atom-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: alg-geom
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The categories of this paper are: eess
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The categories of this paper are: hep-ex