Energy conservation and quantum backreaction in Bose-Einstein condensates

TL;DR

This paper investigates quantum backreaction effects in 1D Bose-Einstein condensates, emphasizing energy and momentum conservation, and reveals complex energy transfer patterns due to quantum fluctuations.

Contribution

It introduces a framework for analyzing quantum backreaction in BECs considering energy conservation and demonstrates non-trivial energy transfer behaviors.

Findings

Energy in condensates depends on the system's entry into the interacting regime.

Quantum fluctuations induce non-monotonic energy transfer patterns.

Backreaction effects are significant even in homogeneous condensates.

Abstract

Bose-Einstein condensates are suitable systems for studying fundamental aspects of quantum backreaction. Here the backreaction problem in 1D condensates is considered from the perspective of energy and momentum conservation. By assuming the validity of Bogoliubov theory, the backreaction equations are used to identify the contributions to the system energy and momentum coming from quantum fluctuations and condensate corrections. The backreaction is solved for a condensate trapped in a ring configuration and such that particle interactions are continuously switched on. It is shown that the energy in the condensate cannot be addressed without taking into account how the system entered the interacting regime, and even for homogeneous condensates the power transferred to the condensate by quantum fluctuations showcases an intricate non-monotonic pattern.