Bound Dimers in Bilayers of Cold Polar Molecules

TL;DR

This paper investigates the formation and properties of bound dimers of cold polar molecules confined in bilayer geometries, analyzing how dipole orientation affects bound states and implications for many-body physics.

Contribution

It provides analytical and numerical evidence for bound states of polar molecules in bilayers across various dipole orientations and strengths, highlighting the role of s- and p-wave components.

Findings

Bound states exist for all dipole moments and polarization angles.

p-wave component can exceed 40% of the bound state structure.

Bound states influence potential many-body ground states.

Abstract

The exploration of cold polar molecules in different geometries is a rapidly developing experimental and theoretical pursuit. Recently, the implementation of optical lattices has enabled confinement in stacks of planes, the number of which is also controllable. Here we consider the bound state structure of two polar molecules confined in two adjacent planes as function of the polarization angle of the dipole moment of the molecules. We prove analytically and present numerical evidence for the existence of bound states for arbitrary dipole moments and polarization directions in this two-dimensional geometry. The spatial structure of the bound states is dominated by two-dimensional s- and p-waves, where the latter exceeds 40 percent over a large range of polarization angles for intermediate or strong dipole strength. Finally, we consider the influence of the dimer bound states on the potential many-body ground-state of the system.