Suppression of Local Decay in non-Markovian Waveguide QED

TL;DR

This paper explores how non-Markovian interactions in waveguide QED can suppress local decay in subradiant states, enhancing their potential for long-lived quantum information storage.

Contribution

It introduces a method to break local decay limits in subradiant states by utilizing non-Markovian regimes and self-interference effects in waveguide QED systems.

Findings

Ultra-small decay rates due to retarded interactions

Spontaneous suppression of local decay via self-interference

Enhanced long-lifetime quantum states in non-Markovian regimes

Abstract

Atoms coupled to the same environment interfere with each other to yield super- or sub-radiance. Specifically, atoms in subradiant states are promising candidates for long-lifetime qubits and quantum memory because of the immunity to the common environment. However, subradiant states can still be influenced by local environments, which are incoherent for different atoms and cannot be canceled out through interference. Here we propose to break this limit by preparing a waveguide QED system in the non-Markovian regime, where the ultra-small decay rate arises because of the retarded interaction. We further show that similar effect occurs spontaneously by self-interference and can be stressed by cooperative coupling.