# Spontaneous interlayer superfluidity in bilayer systems of cold polar molecules

## TL;DR

This paper predicts the emergence of novel superfluid and ferromagnetic states with spontaneous interlayer coherence in bilayer systems of ultracold polar molecules, driven by long-range dipole-dipole interactions.

## Contribution

It introduces the theoretical prediction of spontaneous interlayer superfluidity and related broken-symmetry states in cold polar molecule bilayers, a new phase not previously identified.

## Key findings

- Predicted observable interlayer coherence in cold polar molecule bilayers
- Identified properties akin to superfluids, ferromagnets, and excitonic condensates
- Highlighted the role of long-range dipole-dipole interactions in stabilizing these states

## Abstract

Quantum degenerate cold-atom gases provide a remarkable opportunity to study strongly interacting systems. Recent experimental progress in producing ultracold polar molecules with a net electric dipole moment opens up new possibilities to realize novel quantum phases governed by the long-range and anisotropic dipole-dipole interactions. In this work we predict the existence of experimentally observable novel broken-symmetry states with spontaneous interlayer coherence in cold polar molecules. These exotic states appear due to strong repulsive interlayer interactions and exhibit properties of superfluids, ferromagnets and excitonic condensates.