Casimir-Polder Shift and Decay Rate in the Presence of Nonreciprocal Media

TL;DR

This paper generalizes the calculation of Casimir-Polder shifts and decay rates for atoms near nonreciprocal media, revealing different distance dependencies and applying the theory to topological insulators with broken time-reversal symmetry.

Contribution

It extends macroscopic quantum electrodynamics to nonreciprocal media, providing new insights into atom-surface interactions with broken time-reversal symmetry.

Findings

Different power laws for distance dependence in retarded and nonretarded limits.

Contrast between reciprocal and nonreciprocal mirror effects.

Application to topological insulators with time-symmetry breaking.

Abstract

We calculate the Casimir-Polder frequency shift and decay rate for an atom in front of a nonreciprocal medium by using macroscopic quantum electrodynamics. The results are a generalization of the respective quantities for matter with broken time-reversal symmetry which does not fulfill the Lorentz reciprocity principle. As examples, we contrast the decay rates, the resonant and nonresonant frequency shifts of a perfectly conducting (reciprocal) mirror to those of a perfectly reflecting nonreciprocal mirror. We find different power laws for the distance dependence of all quantities in the retarded and nonretarded limits. As an example of a more realistic nonreciprocal medium, we investigate a topological insulator subject to a time-symmetry breaking perturbation.