Nonlinearity from quantum mechanics: Dynamically unstable Bose-Einstein condensate in a double-well trap

TL;DR

This paper explores how measurements can induce classical-like nonlinear dynamics in a quantum Bose-Einstein condensate within a double-well trap, despite quantum mechanics alone not showing such behavior.

Contribution

It demonstrates that measurement-induced effects can cause a quantum condensate to exhibit classical nonlinear oscillations, bridging quantum and classical dynamics.

Findings

Measurements can induce classical nonlinear oscillations in quantum BECs.

Quantum mechanics alone does not produce large-scale oscillations.

Measurement back-action influences condensate dynamics.

Abstract

We study theoretically an atomic Bose-Einstein condensate in a double-well trap both quantum mechanically and classically under conditions such that in the classical model an unstable equilibrium dissolves into large-scale oscillations of the atoms between the potential wells. Quantum mechanics alone does not exhibit such nonlinear dynamics, but measurements of the atom numbers in the potential wells may nevertheless cause the condensate to behave essentially classically.