Dissipation effect in the double-well Bose-Einstein Condensate

TL;DR

This study investigates how energy dissipation influences the dynamics of a double-well Bose-Einstein condensate, showing that dissipation guides the system from a self-trapped state to an equilibrium with equal particle distribution.

Contribution

The paper provides a numerical analysis of dissipative effects on double-well BEC dynamics, including phase space evolution and phase distribution behavior, which was not previously detailed.

Findings

Dissipation causes the system to evolve from a self-trapping state to an equal distribution state.

Phase distribution in each well changes slowly but can have abrupt shifts near the barrier.

Average phase in each well varies faster than the phase difference between wells.

Abstract

Dynamics of the double-well Bose-Einstein condensate subject to energy dissipation is studied by solving a reduced one-dimensional time-dependent Gross-Pitaevskii equation numerically. We first reproduce the phase space diagram of the system without dissipation systematically, and then calculate evolutionary trajectories of dissipated systems. It is clearly shown that the dissipation can drive the system to evolve gradually from the $\pi$-mode quantum macroscopic self-trapping state, a state with relatively higher energy, to the lowest energy stationary state in which particles distribute equally in the two wells. The average phase and phase distribution in each well are discussed as well. We show that the phase distribution varies slowly in each well but may exhibit abrupt changes near the barrier. This sudden change occurs at the minimum position in particle density profile. We also note that the average phase in each well varies much faster with time than the phase difference between two wells.