Eur. Phys. J. D 21, 251-254 (2002)
https://doi.org/10.1140/epjd/e2002-00229-5

Mean field loops versus quantum anti-crossing nets in trapped Bose-Einstein condensates

¹ Theoretical Division and Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, NM 87545 USA
² Instytut Fizyki, Uniwersytet Jagielloński, ulica Reymonta 4, 30-059 Kraków, Poland

Corresponding author: ^a smerzi@cnls.lanl.gov

Received: 6 March 2002
Revised: 19 September 2002
Published online: 15 November 2002

Abstract

We study a Bose-Einstein condensate trapped in an asymmetric double well potential. Solutions of the time-independent Gross-Pitaevskii equation reveal intrinsic loops in the energy (or chemical potential) level behavior when the shape of the potential is varied. We investigate the corresponding behavior of the quantum (many-body) energy levels. Applying the two-mode approximation to the bosonic field operators, we show that the quantum energy levels create an anti-crossing net inside the region bounded by the loop of the mean field solution.