From Cosmology to Cold Atoms: Observation of Sakharov Oscillations in Quenched Atomic Superfluids

TL;DR

This paper demonstrates Sakharov oscillations in a laboratory atomic superfluid, linking cosmological phenomena to condensed matter physics through controlled quenches and in situ imaging.

Contribution

It provides the first experimental observation of Sakharov oscillations in a quenched atomic superfluid, bridging cosmology and quantum fluid dynamics.

Findings

Observation of multi-peak structure in density power spectrum

Detection of Sakharov oscillations in time domain

Extraction of superfluid energy dispersion and sonic horizon

Abstract

Sakharov oscillations, conventionally discussed in the context of early universe evolution and the anisotropy of cosmic microwave background radiation, is the manifestation of interfering acoustic waves synchronously generated in an ideal fluid. Here we report the laboratory demonstration of Sakharov oscillations in a quenched atomic superfluid. We quench the sample by Feshbach tuning and monitor the subsequent density fluctuations at different time and length scales by in situ imaging. Sakharov oscillations are identified as the multi-peak structure in the atomic density power spectrum, resembling that of the cosmic microwave background. We also observe Sakharov oscillations in the time domain, from which we extract the energy dispersion of the superfluid, and determine the sonic horizon of the excitations.