Role of excited states in the splitting dynamics of interacting Bose-Einstein condensates when ramping-up a barrier

TL;DR

This paper develops an nearly exact method to study how many-body excited states influence the splitting of a Bose-Einstein condensate when forming a double-well, revealing a counter-intuitive slow-ramp regime leading to an excited-state condensate.

Contribution

An essentially exact computational approach is introduced to analyze the role of excited states in BEC splitting dynamics, highlighting a novel slow-ramp regime leading to excited-state condensates.

Findings

Identification of a counter-intuitive slow-ramp regime

Excited states can dominate the splitting process

Implications for experimental control of BEC splitting

Abstract

An essentially-exact approach to compute the wavefunction in the time-dependent many-boson Schr\"odinger equation is derived and employed to study accurately the process of splitting a trapped condensate when ramping-up a barrier such that a double-well is formed. We follow the role played by many-body excited states during the splitting process. Among others, a 'counter-intuitive' regime is found in which the evolution of the condensate when the barrier is ramped-up sufficiently slow {\it is not} to the ground-state which is a fragmented condensate, but to a low-lying excited-state which is a coherent condensate. Experimental implications are discussed.