In-situ tuning of cavity dissipation and a topological transition in an atom-nanotip-cavity system

TL;DR

This paper proposes a method to tune cavity dissipation in an atom-nanotip-cavity system, enabling control over exceptional points and topological transitions through dissipation adjustment.

Contribution

It introduces an in-situ technique for tuning dissipation rates in cavity systems using a nanotip, facilitating topological transitions without altering the system's structure.

Findings

Cavity dissipation can be increased by a factor of 20 with a nanotip.

Exceptional points can be achieved with a single atom or ion in the resonator.

Dissipation control enables topological transitions in the system.

Abstract

We theoretically investigate a method for tuning a dissipation rate in an atom-cavity system. By inserting a nanotip into the cavity mode, we estimate that the cavity dissipation rate increases by a factor of approximately 20, due to the scattering loss at the tip. As applications of our in-situ technique, we demonstrate that an exceptional line can be obtained when a single atom or ion is coupled to the resonator. Moreover, the position of an exceptional point is tuned by adjusting the decay rate, enabling a topological transition through dissipation control alone.