Pattern formation in driven condensates

TL;DR

This paper reviews the progress in understanding pattern formation in driven Bose-Einstein condensates, highlighting theoretical predictions, experimental confirmations, and recent observations of stable lattice patterns with supersolid features.

Contribution

It provides a comprehensive overview of two decades of research on driven pattern formation in BECs, including the first predictions and recent experimental realizations of complex patterns.

Findings

Prediction of parametric instabilities and Faraday waves in driven condensates

Experimental confirmation of pattern formation mechanisms

Observation of a stabilized square lattice pattern with supersolid features

Abstract

The onset of pattern formation in a spatially homogeneous system subjected to external driving is an important topic in various scientific fields. A celebrated classical example is the Faraday instability, where a vertically oscillated fluid surface undergoes a parametric resonance, giving rise to standing waves that self-organize into regular spatial patterns. Bose-Einstein condensates (BECs) provide an ideal quantum-mechanical platform for studying pattern-forming mechanisms due to their exceptional degree of experimental control. As a compressible state of quantum matter, a condensate responds sensitively to external perturbations, including time-periodic modulation of interactions, trapping potentials, or external fields. These features make BECs particularly well suited for exploring driven nonequilibrium phases and pattern formation. In this chapter, we review the remarkable progress achieved in this field over the past two decades. We begin with the first theoretical proposal predicting parametric instabilities and emergent Faraday waves in driven condensates. We then discuss key experimental and theoretical breakthroughs that confirmed these predictions and refined the understanding of the underlying mechanisms. This line of research has culminated in the recent observation of a stabilized square lattice pattern in a periodically driven BEC confined in a two-dimensional geometry. This driven superfluid state with superposed density modulation was shown to exhibit some features of a supersolid state.