Polaron effects on the information backflow in Jaynes-Cummings model

TL;DR

This paper explores how phonon interactions influence the non-Markovian dynamics of a qubit in the Jaynes-Cummings model, revealing that polaronic effects can suppress memory effects and alter coherence properties.

Contribution

It introduces a Jaynes-Cummings-Holstein model with analytical solutions showing how phonon coupling modifies non-Markovian behavior and coherence in qubit-cavity systems.

Findings

Non-zero phonon coupling suppresses non-Markovian features.

Polaronic dressing reduces detuning effects.

Memory effects are extended over wider spectral densities.

Abstract

We investigate the influence of phonon degrees of freedom on the qubit dynamics in Jaynes-Cummings (JC) model. A strong qubit-phonon coupling is considered giving rise to Jaynes-Cummings-Holstein (JCH) model. Under anti-adiabatic conditions, we perform a unitary transformation to make the underlying problem tractable through Redfield-type non-Markovian master equation. Analytical expression for the time-dependent coherence is obtained, incorporating both cavity-induced dissipation and phonon-induced dressing effects. The dynamics of JC model is highly non-Markovian for a narrow spectral width and finite detuning. However, a non-zero phonon coupling suppresses these non-Markovian features by effectively reducing the qubit-cavity interaction strength. {It is observed that polaronic dressing effectively supresses the detuning effects. Furthermore, the coherence-based non-Markovianity measure shows an order-of-magnitude suppression in the JCH model, indicating a new dynamical regime, while memory effects extend over a wider range of spectral densities than in the JC model.