
RRI Digital Repository >
07. Theoretical Physics >
Research Papers (TP) >
Please use this identifier to cite or link to this item:
http://hdl.handle.net/2289/1321

Title:  Rotating Bose gas with hardcore repulsion in a quasitwodimensional harmonic trap: Vortices in BoseEinstein condensates 
Authors:  Ahsan, M.A.H. Kumar, N. 
Issue Date:  Jul2001 
Publisher:  The American Physical Society 
Citation:  Physical Review A, 2001, Vol.64, 013608 
Abstract:  We consider a gas of N(<~15) Bose particles with hardcore repulsion, contained in a quasitwodimensional harmonic trap and subjected to an overall angular velocity Ω about the z axis. Exact diagonalization of the n×n manybody Hamiltonian matrix in given subspaces of the total (quantized) angular momentum Lz, with n∼105 (e.g., for Lz=N=15, n=240 782) was carried out using Davidson’s algorithm. The manybody variational groundstate wave function, as also the corresponding energy and the reduced oneparticle densitymatrix ρ(r,r′)=∑μλμχμ*(r)χμ(r′) were determined. With the usual identification of Ω as the Lagrange multiplier associated with Lz for a rotating system, the LzΩ phase diagram (or the stability line) was determined that gave a number of critical angular velocities Ωci, i=1,2,3,…, at which the groundstate angular momentum and the associated condensate fraction, given by the largest eigenvalue of the reduced oneparticle density matrix, undergo abrupt jumps. For a given N, a number of (total) angular momentum states were found to be stable at successively higher critical angular velocities Ωci, i=1,2,3,…. All the states in the regime N>Lz>0 are metastable. For Lz>N, the Lz values for the stable ground states generally increased with increasing critical angular velocities Ωci, and the condensate was strongly depleted. The critical Ωci values, however, decreased with increasing interaction strength as well as the particle number, and were systematically greater than the nonvariational yraststate values for the Lz=N single vortex state. 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 twobody interaction strength was varied over several (∼4) orders of magnitude in the moderately to the weakly interacting regime. 
URI:  http://hdl.handle.net/2289/1321 
ISSN:  10941622 (online) 10502947 
Alternative Location:  http://link.aps.org/abstract/PRA/v64/e013608 
Copyright:  (2001) by the American Physical Society 
Appears in Collections:  Research Papers (TP)

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.
