Critical number of atoms in an attractive Bose-Einstein condensate on an optical plus harmonic traps

TL;DR

This paper investigates the stability of an attractive Bose-Einstein condensate in combined optical and harmonic traps, calculating the critical atom number for stability and how it can be manipulated experimentally.

Contribution

It provides numerical calculations of the critical atom number in combined traps and explores how optical lattice configurations affect condensate stability.

Findings

Critical atom number depends on trap configuration.

Double-well potential increases critical atom number.

Moving optical lattice nodes alters stability thresholds.

Abstract

The stability of an attractive Bose-Einstein condensate on a joint one-dimensional optical lattice and an axially-symmetric harmonic trap is studied using the numerical solution of the time-dependent mean-field Gross-Pitaevskii equation and the critical number of atoms for a stable condensate is calculated. We also calculate this critical number of atoms in a double-well potential which is always greater than that in an axially-symmetric harmonic trap. The critical number of atoms in an optical trap can be made smaller or larger than the corresponding number in the absence of the optical trap by moving a node of the optical lattice potential along the axial direction of the harmonic trap. This variation of the critical number of atoms can be observed experimentally and compared with the present calculation.