Parametrically excited "Scars" in Bose-Einstein condensates

TL;DR

This paper investigates how parametric excitation in Bose-Einstein condensates leads to density modulations, revealing scarred density patterns aligned with classical periodic orbits, influenced by nonlinear effects and dephasing.

Contribution

It demonstrates that nonlinear effects in BECs favor stripe-like scar patterns associated with self-retracing periodic orbits, extending understanding of quantum-classical correspondence in nonlinear systems.

Findings

Density waves are concentrated along classical periodic orbits in irregular traps.

Nonlinear effects select stripe-like scars associated with self-retracing orbits.

Dephasing reduces nonlocal interference, emphasizing local scar patterns.

Abstract

Parametric excitation of a Bose-Einstein condensate (BEC) can be realized by periodically changing the interaction strength between the atoms. Above some threshold strength, this excitation modulates the condensate density. We show that when the condensate is trapped in a potential well of irregular shape, density waves can be strongly concentrated ("scarred") along the shortest periodic orbits of a classical particle moving within the confining potential. While single-particle wave functions of systems whose classical counterpart is chaotic may exhibit rich scarring patterns, in BEC, we show that nonlinear effects select mainly those scars that are locally described by stripes. Typically, these are the scars associated with self retracing periodic orbits that do not cross themselves in real space. Dephasing enhances this behavior by reducing the nonlocal effect of interference.