Superfluid-quasicrystal in a Bose-Einstein condensate

TL;DR

This paper demonstrates that a Bose-Einstein condensate can spontaneously form a superfluid-quasicrystal with 5-fold symmetry, revealing a new phase of quantum matter with potential for exploring exotic states.

Contribution

The authors propose a practical scheme to realize superfluid-quasicrystals in a BEC, introducing a new quantum phase with 5-fold symmetry not present in the Hamiltonian.

Findings

Ground state of BEC can be a superfluid-quasicrystal with 5-fold symmetry.

Phase diagram includes superfluid-quasicrystal, supersolid, and plane-wave phases.

Scheme can be extended to generate higher-order quasicrystals like 7-fold.

Abstract

Quasicrystal is a class of ordered structures defying conventional classification of solid crystals and may carry classically forbidden (e.g., 5-fold) rotational symmetries. In view of long-sought supersolids, a natural question is whether a superfluid can spontaneously form quasicrystalline order that is not possessed by the underlying Hamiltonian, forming "superfluid-quasicrystals". Here we show that a superfluid-quasicrystal stripe state with the minimal 5-fold rotational symmetry can be realized as the ground state of a Bose-Einstein condensate within a practical experimental scheme. There exists a rich phase diagram consisting of various superfluid-quasicrystal, supersolid, and plane-wave phases. Our scheme can be generalized for generating other higher-order (e.g., 7-fold) quasicrystal states, and provides a platform for investigating such new exotic quantum matter.