Decoherence suppression of a dissipative qubit by the non-Markovian effect

TL;DR

This paper demonstrates that non-Markovian effects can partially preserve qubit coherence in a dissipative environment by forming bound states, offering a new approach for decoherence control through reservoir engineering.

Contribution

It provides an exact analysis of non-Markovian effects on qubit decoherence and identifies conditions for coherence trapping via bound state formation.

Findings

Partial coherence trapping in steady state due to non-Markovian effects

Formation of bound states between qubit and reservoir causes residual coherence

Decoherence suppression can be achieved by engineering system-reservoir interactions

Abstract

We evaluate exactly the non-Markovian effect on the decoherence dynamics of a qubit interacting with a dissipative vacuum reservoir and find that the coherence of the qubit can be partially trapped in the steady state when the memory effect of the reservoir is considered. Our analysis shows that it is the formation of a bound state between the qubit and its reservoir that results in this residual coherence in the steady state under the non-Markovian dynamics. A physical condition for the decoherence suppression is given explicitly. Our results suggest a potential way to decoherence control by modifying the system-reservoir interaction and the spectrum of the reservoir to the non-Markovian regime in the scenario of reservoir engineering.