Interaction of a Bose-Einstein condensate with a gravitational wave

TL;DR

This paper explores how gravitational waves interact with Bose-Einstein condensates, revealing that inhomogeneous flows can directly generate phonons, which could aid in gravitational wave detection.

Contribution

It demonstrates that inhomogeneous Bose-Einstein condensates can directly produce phonons via gravitational waves, suggesting a potential new detection method.

Findings

Homogeneous condensates do not produce phonons directly from gravitational waves.

Inhomogeneous flows like vortex lattices can generate phonons directly.

Superfluid Helium may offer advantages for gravitational wave detection.

Abstract

Partly motivated by recent proposals for the detection of gravitational waves, we study their interaction with Bose-Einstein condensates. For homogeneous condensates at rest, the gravitational wave does not directly create phonons (to lowest order), but merely affects existing phonons or indirectly creates phonon pairs via quantum squeezing -- an effect which has already been considered in the literature. For inhomogeneous condensate flows such as a vortex lattice, however, the impact of the gravitational wave can directly create phonons. This more direct interaction can be more efficient and could perhaps help bringing such a detection mechanism for gravitational waves a step closer towards experimental realizability -- even though it is still a long way to go. Finally, we argue that super-fluid Helium might offer some advantages in this respect.