The dynamical role of initial correlation in the exactly solvable dephasing model

TL;DR

This paper explores how initial correlations influence the dynamics of a qubit in a dephasing model, revealing effects on decoherence, entanglement revival, and control strategies, with implications for quantum information processing.

Contribution

It provides an exact analysis of the impact of initial correlations on open quantum system dynamics, highlighting their role in decoherence and entanglement behavior.

Findings

Initial correlations cause oscillations in phase and weight factors affecting dynamics.

Decoherence is more pronounced in a boson bath compared to a spin bath in short times.

Initial correlations can enhance entanglement revival and influence decoherence suppression.

Abstract

We investigate the effects of the initial correlation on the dynamics of open system in the exactly solvable pure dephasing model. We show that the role of the initial correlation come into play through a phase function and a weight factor, which would perform oscillations during time evolution, and find that the decoherence of a qubit coupled to a boson bath is more enhanced with respect to a spin bath in the short time. We also demonstrate that the trace distance between two states of a qubit can increase above its initial value, and that the initial correlation can provide another resource for the damply oscillation and revival of the entanglement of two qubits. We finally investigate the dependence of the crossover of decoherence from the dynamical enhancement to suppression under the bang-bang pulse control on the initial correlation and the statistics of the bath constituents.