Superglass formation in an atomic BEC with competing long-range interactions

TL;DR

This paper investigates a quantum many-body system where competing long-range interactions in a 2D BEC lead to a superglass phase, characterized by local density modulations without long-range order, driven by quantum fluctuations and frustration.

Contribution

It demonstrates the emergence of a superglass phase in a 2D BEC with competing long-range interactions, highlighting a new route to disordered quantum phases without external disorder.

Findings

Superglass phase arises from incommensurate length scales of interactions.

Quantum fluctuations and frustration drive the formation of the superglass.

Dynamic pattern formation occurs without external disorder.

Abstract

The complex dynamical phases of quantum systems are dictated by atomic interactions that usually evoke an emergent periodic order. Here, we study a quantum many-body system with two competing and substantially different long-range interaction potentials where the dynamical instability towards density order can give way to a superglass phase, i. e., a superfluid disordered amorphous solid, which exhibits local density modulations but no long-range periodic order. We consider a two-dimensional BEC in the Rydberg-dressing regime coupled to an optical standing wave resonator. The dynamic pattern formation in this system is governed by the competition between the two involved interaction potentials: repulsive soft-core interactions arising due to Rydberg dressing and infinite-range sign changing interactions induced by the cavity photons. The superglass phase is found when the two interaction potentials introduce incommensurate length scales. The dynamic formation of this peculiar phase without any externally added disorder is driven by quantum fluctuations and can be attributed to frustration induced by the two competing interaction energies and length scales.