Cavity Quantum Optomechanics of Ultracold Atoms in an Optical Lattice: Normal-Mode Splitting

TL;DR

This paper explores the interaction between ultracold atoms in an optical lattice and a movable mirror in a cavity, revealing phenomena like bistability and normal-mode splitting influenced by atomic states and back-action effects.

Contribution

It introduces a novel cavity optomechanics setup with ultracold atoms, demonstrating how atomic states affect cantilever dynamics and mode splitting.

Findings

Displacement spectrum depends on atomic quantum states.

Bistable behavior of the cantilever at high pump intensities.

Normal-mode splitting into three modes due to atom-cavity-mechanical interactions.

Abstract

We consider the dynamics of a movable mirror (cantilever) of a cavity coupled through radiation pressure to the light scattered from ultracold atoms in an optical lattice. Scattering from different atomic quantum states creates different quantum states of the scattered light, which can be distinguished by measurements of the displacement spectrum of the cantilever. We show that for large pump intensities the steady state displacement of the cantilever shows bistable behaviour. Due to atomic back-action, the displacement spectrum of the cantilever is modified and depends on the position of the condensate in the Brillouin zone. We further analyze the occurrence of splitting of the normal mode into three modes due to mixing of the mechanical motion with the fluctuations of the cavity field and the fluctuations of the condensate with finite atomic two-body interaction. The present system offers a novel scheme to coherently control ultracold atoms as well as cantilever dynamics.