Dynamics of Bose-Einstein condensates in a one-dimensional optical lattice with double-well potential

TL;DR

This paper investigates the dynamics of weakly interacting Bose-Einstein condensates in a one-dimensional optical lattice with a double-well potential, revealing how the potential influences flow, effective mass, and nonlinearity.

Contribution

It demonstrates that the double-well potential dominates condensate dynamics even in deep lattices and shows increased effective mass and nonlinearity effects.

Findings

Double-well potential governs condensate dynamics despite deep lattices.

Effective mass of atoms is increased, affecting Josephson oscillations.

Lattice enhances nonlinearity, promoting self-trapping in the $\

Abstract

We study dynamical behaviors of the weakly interacting Bose-Einstein condensate in the one-dimensional optical lattice with an overall double-well potential by solving the time-dependent Gross-Pitaevskii equation. It is observed that the double-well potential dominates the dynamics of such a system even if the lattice depth is several times larger than the height of the double-well potential. This result suggests that the condensate flows without resistance in the periodic lattice just like the case of a single particle moving in periodic potentials. Nevertheless, the effective mass of atoms is increased, which can be experimentally verified since it is connected to the Josephson oscillation frequency. Moreover, the periodic lattice enhances the nonlinearity of the double-well condensate, making the condensate more "self-trapped" in the $\pi$-mode self-trapping regime.