Tuning non-Markovianity by spin-dynamics control

TL;DR

This paper demonstrates how the non-Markovian behavior of a two-level quantum system can be controlled through spin-dynamics, showing a transition from Markovian to non-Markovian regimes by tuning system-environment parameters.

Contribution

It reveals that non-Markovianity can be tuned in a multi-spin environment, challenging the expectation that memory effects are always suppressed by decoherence mechanisms.

Findings

Non-Markovianity can be induced and controlled by system parameters.

The non-Markovianity increases with the number of decoherence channels.

A full transition from Markovian to non-Markovian dynamics is achievable.

Abstract

We study the interplay between forgetful and memory-keeping evolution enforced on a two-level system by a multi-spin environment whose elements are coupled to local bosonic baths. Contrarily to the expectation that any non-Markovian effect would be buried by the forgetful mechanism induced by the spin-bath coupling, one can actually induce a full Markovian-to-non-Markovian transition of the two-level system's dynamics, controllable by parameters such as the mismatch between the energy of the two-level system and of the spin environment. For a symmetric coupling, the amount of non-Markovianity surprisingly grows with the number of decoherence channels.