Non-Markovian evolution of a two-level system interacting with a fluctuating classical field via dipole interaction

TL;DR

This paper investigates non-Markovian dynamics in a two-level quantum system interacting with a classical fluctuating field, revealing regimes where memory effects are driven by system energy or interaction energy, and showing non-Markovianity increases over time.

Contribution

It introduces a detailed analysis of memory effects in a two-level system with classical field fluctuations, identifying two regimes governed by different energy scales.

Findings

Memory effects depend on the energy gap or interaction energy.

Non-Markovianity increases with time despite dissipative interactions.

Memory effects could be observed in practical quantum systems.

Abstract

We address memory effects in the dynamics of a two-level open quantum system interacting with a classical fluctuating field via dipole interaction. In particular, we study the backflow of information for a field with a Lorentzian spectrum, and reveal the existence of two working regimes, where memory effects are governed either by the energy gap of the two-level system, or by the interaction energy. Our results shows that non-Markovianity increases with time, at variance with the results obtained for dephasing and despite the dissipative nature of the interaction, thus suggesting that the corresponding memory effects might be observed in practical scenarios.