Controllable binding of polar molecules and meta-stability of 1-D gases with attractive dipole forces

TL;DR

This paper investigates the stabilization and controllability of ultracold polar molecules in one-dimensional systems with attractive dipole interactions, revealing mechanisms for creating bound states and chains via external fields.

Contribution

It demonstrates the existence of a repulsive barrier due to quadrupole interactions that stabilizes 1-D gases of polar molecules and enables control over bound states and polymer-like chains.

Findings

Existence of a quadrupole-induced repulsive barrier stabilizing the gas.

Formation of long-range bound states and chains of molecules.

External electric fields can tune the properties of these bound states.

Abstract

We explore one-dimensional (1-D) samples of ultracold polar molecules with attractive dipole-dipole interactions and show the existence of a repulsive barrier due to a strong quadrupole interaction between molecules. This barrier can stabilize a gas of ultracold KRb molecules and even lead to long-range wells supporting bound states between molecules. The properties of these wells can be controlled by external electric fields, allowing the formation of long polymer-like chains of KRb, and studies of quantum phase transitions by varying the effective interaction between molecules. We discuss the generalization of those results to other systems.