Decoherence dynamics of open qubit systems

TL;DR

This paper investigates how bound states between qubits and their environment influence decoherence, showing that non-Markovian effects can significantly suppress decoherence and preserve entanglement, with implications for quantum information processing.

Contribution

It provides a unified framework revealing the role of bound states in decoherence suppression and entanglement preservation in open qubit systems, including explicit criteria for control.

Findings

Decoherence can be greatly suppressed when a bound state forms.

Entanglement can be partially preserved in steady state.

A criterion for decoherence and disentanglement suppression is established.

Abstract

The thesis is contributed to the study of the decoherence dynamics of dissipative qubit systems. We reveal the profound impact of the formation of a bound state between the qubit and its local environment on the decoherence dynamics of qubit system in non-Markovian regime. We find that the decoherence can be suppressed greatly under the non-Markovian dynamics when the bound state is formed. Consequently, the entanglement can be partially preserved in the steady state. A criterion on this decoherence/disentanglement suppression is given explicitly. It can give a useful guideline on the decoherence control in experiment. We also find that the entanglement can be stably distributed among all components and particularly it always satisfies an identity. Our unified treatment includes the previous results in the literatures as special cases. The result reveals the profound nature of the entanglement and should have significant implications for quantum information processing.