Nonexponential decay of Bose-Einstein condensates: a numerical study based on the complex scaling method

TL;DR

This paper investigates the nonexponential decay behavior of interacting Bose-Einstein condensates in metastable traps, using complex scaling to calculate decay rates and revealing deviations from simple exponential decay.

Contribution

It introduces a numerical approach employing complex scaling to analyze decay dynamics of interacting BECs, highlighting nonexponential decay due to atom interactions.

Findings

Decay deviates from exponential in double barrier potential

Decay deviates from exponential in tilted periodic potential

Interactions significantly influence decay dynamics

Abstract

We study the decay dynamics of an interacting Bose-Einstein condensate in the presence of a metastable trapping potential from which the condensate can escape via tunneling through finite barriers. The time-dependent decay process is reproduced by means of the instantaneous decay rates of the condensate at a given population of the quasi-bound state, which are calculated with the method of complex scaling. Both for the case of a double barrier potential as well as for the case of a tilted periodic potential, we find pronounced deviations from a monoexponential decay behaviour which would generally be expected in the absence of the atom-atom interaction.