Quantum phase transitions of polar molecules in bilayer systems

TL;DR

This paper explores quantum phase transitions in bilayer systems of polar molecules, revealing how interlayer bound states and entanglement emerge near a zero-energy resonance, with implications for experimental detection.

Contribution

It introduces the formation of interlayer dimers and maximally entangled states in polar molecule bilayers near a zero-energy resonance, advancing understanding of quantum phase transitions in such systems.

Findings

Interlayer bound states form above a critical dipole strength.

Zero-energy resonance leads to maximally entangled states.

Proposed experimental methods to detect these states.

Abstract

We investigate the quantum phase transitions of bosonic polar molecules in a two-dimensional double layer system. We show that an interlayer bound state of dipoles (dimers) can be formed when the dipole strength is above a critical value, leading to a zero-energy resonance in the interlayer s-wave scattering channel. In the positive detuning side of the resonance, the strong repulsive interlayer pseudopotential can drive the system into a maximally entangled state, where the wave function is a superposition of two states that have all molecules in one layer and none in the other. We discuss how the zero-energy resonance, dimer states, and the maximally entangled state can be measured in time-of-flight experiments.