Triangular and Honeycomb Lattices of Cold Atoms in Optical Cavities

TL;DR

This paper investigates how cold bosonic atoms in optical cavities self-organize into triangular or honeycomb lattices via superradiance, with the ability to switch between structures by phase control of cavity fields.

Contribution

It demonstrates the formation of stable triangular and honeycomb atomic lattices in cavity QED systems and explores dynamic phase control to switch lattice structures.

Findings

Atoms self-organize into stable triangular and honeycomb lattices.

The phase of cavity fields determines the lattice geometry.

Dynamic phase changes can switch lattice structures.

Abstract

We consider a two-dimensional homogeneous ensemble of cold bosonic atoms loaded inside two optical cavities and pumped by a far-detuned external laser field. We examine the conditions for these atoms to self-organize into triangular and honeycomb lattices as a result of superradiance. By collectively scattering the pump photons, the atoms feed the initially empty cavity modes. As a result, the superposition of the pump and cavity fields creates a space-periodic light-shift external potential and atoms self-organize into the potential wells of this optical lattice. Depending on the phase of the cavity fields with respect to the pump laser, these minima can either form a triangular or a hexagonal lattice. By numerically solving the dynamical equations of the coupled atom-cavity system, we have shown that the two stable atomic structures at long times are the triangular lattice and the honeycomb lattice with equally-populated sites. We have also studied how to drive atoms from one lattice structure to another by dynamically changing the phase of the cavity fields with respect to the pump laser.