Supersolid stripe crystal from finite-range interactions on a lattice

TL;DR

This paper explores a class of extended bosonic Hubbard models with varying interaction ranges, predicting a novel stripe crystal phase that can transition into a superfluid and supersolid, revealing new self-assembly mechanisms.

Contribution

It introduces a new model with tunable interaction range and demonstrates the emergence of stripe crystals, superfluids, and supersolids through exact numerical solutions.

Findings

Prediction of a novel stripe crystal phase at strong coupling.

Demonstration of stripe superfluidity at intermediate interactions.

Identification of a self-assembly mechanism based on classical cluster formation.

Abstract

Strong, long-range interactions present a unique challenge for the theoretical investigation of quantum many-body lattice models, due to the generation of large numbers of competing states at low energy. Here, we investigate a class of extended bosonic Hubbard models with off-site terms interpolating between short and infinite range, thus allowing for an exact numerical solution for all interaction strengths. We predict a novel type of stripe crystal at strong coupling. Most interestingly, for intermediate interaction strengths we demonstrate that the stripes can turn superfluid, thus leading to a self-assembled array of quasi-one-dimensional superfluids. These bosonic superstripes turn into an isotropic supersolid with decreasing the interaction strength. The mechanism for stripe formation is based on cluster self-assembling in the corresponding classical ground state, reminiscent of classical soft-matter models of polymers, different from recently proposed mechanisms for cold gases of alkali or dipolar magnetic atoms.