Quantum Phase Transition between (Luttinger) Liquid and Gas of Cold Molecules

TL;DR

This paper investigates a quantum phase transition in cold polar molecules confined in a helical optical lattice, revealing a zero-temperature liquid-gas transition driven by an external electric field.

Contribution

It demonstrates the existence of a quantum phase transition between a Luttinger liquid and a gas phase in cold molecules, controlled by electric field strength, with potential experimental observation.

Findings

Identified a second-order liquid-gas transition at a critical electric field.

Showed the transition can be observed under accessible experimental conditions.

Analyzed the interplay of attractive and repulsive dipolar interactions in a helical geometry.

Abstract

We consider cold polar molecules confined in a helical optical lattice similar to those used in holographic microfabrication. An external electric field polarizes molecules along the axis of the helix. The large-distance inter-molecular dipolar interaction is attractive but the short-scale interaction is repulsive due to geometric constraints and thus prevents collapse. The interaction strength depends on the electric field. We show that a zero-temperature second-order liquid-gas transition occurs at a critical field. It can be observed under experimentally accessible conditions.