Detection of roton and phonon excitations in a spin-orbit coupled Bose-Einstein condensate with a moving barrier

TL;DR

This paper proposes a method to detect phonon and roton excitations in a spin-orbit coupled Bose-Einstein condensate by perturbing it with a moving barrier, revealing distinct excitations and superfluid properties.

Contribution

It introduces a novel experimental approach to distinguish phonon and roton modes in spin-orbit coupled BECs using a moving barrier.

Findings

Phonon excitations produce solitary waves.

Roton excitations cause spatial density modulations.

Method can determine anisotropic critical velocities.

Abstract

We propose to detect phonon and roton excitations in a two-dimensional Bose-Einstein condensate with Raman-induced spin-orbit coupling by perturbing the atomic cloud with a weak barrier. The two excitation modes can be observed by moving the barrier along different directions in appropriate parameter regimes. Phonon excitations are identified by the appearance of solitary waves, while roton excitations lead to distinctive spatial density modulations. We show that this method can also be used to determine the anisotropic critical velocities of superfluid.