Nano-friction in cavity quantum electrodynamics

TL;DR

This paper explores the complex interplay of Coulomb and cavity-induced interactions in cold trapped ions within a high-finesse resonator, revealing friction-like phenomena, phase behaviors, and cavity-controlled cooling observable through emitted radiation.

Contribution

It introduces a detailed analysis of ion dynamics in cavity QED, connecting Coulomb crystallization with photon-mediated interactions and friction models, including bistability and cooling effects.

Findings

Identification of sliding and pinned phases in ion-cavity systems

Observation of bistable regions with superlubric and stick-slip dynamics

Demonstration of cavity-controlled cooling of ion chains

Abstract

The dynamics of cold trapped ions in a high-finesse resonator results from the interplay between the long-range Coulomb repulsion and the cavity-induced interactions. The latter are due to multiple scatterings of laser photons inside the cavity and become relevant when the laser pump is sufficiently strong to overcome photon decay. We study the stationary states of ions coupled with a mode of a standing-wave cavity as a function of the cavity and laser parameters, when the typical length scales of the two self-organizing processes, Coulomb crystallization and photon-mediated interactions, are incommensurate. The dynamics are frustrated and in specific limiting cases can be cast in terms of the Frenkel-Kontorova model, which reproduces features of friction in one dimension. We numerically recover the sliding and pinned phases. For strong cavity nonlinearities, they are in general separated by bistable regions where superlubric and stick-slip dynamics coexist. The cavity, moreover, acts as a thermal reservoir and can cool the chain vibrations to temperatures controlled by the cavity parameters and by the ions phase. These features are imprinted in the radiation emitted by the cavity, which is readily measurable in state-of-art setups of cavity quantum electrodynamics.