# Fragmented-condensate solid of dipolar excitons

## TL;DR

This paper proposes a theoretical model linking the observed macroscopic ordering of ultracold dipolar excitons to a supersolid state, predicting a transition to a fragmented condensate influenced by interactions and quantum fluctuations.

## Contribution

It introduces a novel theoretical framework connecting supersolidity and exciton ordering, including a phase transition to a fragmented state based on contact interactions.

## Key findings

- Prediction of a stable supersolid state in dipolar excitons
- Identification of a quantum phase transition to a fragmented state
- Agreement with experimental observations of MOES wavelength and behavior

## Abstract

We discuss a possible link between the recently observed macroscopic ordering of ultra cold dipolar excitons (MOES) and the phenomenon of supersolidity. In the dilute limit we predict a stable supersolid state for a quasi-one-dimensional system of bosonic dipoles characterized by two- and three-body contact repulsion. We phenomenologically extend our theory to the strongly-correlated regime and find a critical value of the contact interaction parameter at which the supersolid exhibits a quantum phase transition to a fragmented state. The wavelength of the fragmented-condensate solid is defined by the balance between the quantum pressure and the entropy due to fluctuations of the relative phases between the fragments. Our model appears to be in good agreement with the relevant experimental data, including the very recent results on commensurability effect and wavelength of the MOES.