Modulation of dephasing due to a spin-boson environment

TL;DR

This paper analyzes how a spin-boson environment influences qubit dephasing, deriving exact equations and exploring modulation effects at different dissipation strengths and temperatures.

Contribution

It provides exact formal expressions for qubit dynamics in a spin-boson environment and investigates modulation strategies for dephasing effects.

Findings

Exact integro-differential master equations derived.

Analytic solution found for ohmic damping strength K=1/2.

Modulation of dephasing effects possible by tuning temperature and coupling.

Abstract

We study the reduced dynamics of a spin (qubit) coupled to a spin-boson environment in the case of pure dephasing. We derive formal exact expressions which can be cast in terms of exact integro-differential master equations. We present results for a SB environment with ohmic dissipation at finite temperatures. For the special value of the ohmic damping strength K=1/2 the reduced dynamics is found in analytic form. For K<<1 we discuss the possibility of modulating the effect of the SB environment on the qubit. In particular we study the effect of the crossover to a slow environment dynamics, which may be triggered by changing both the temperature and the system-environment coupling.