Decoherence dynamics in a polaron system with collective dephasing

TL;DR

This study investigates how a polaron system's coherence decays over time under collective dephasing, revealing key timescales and control methods like $$-pulses to manage decoherence.

Contribution

It introduces a polaron-based model with a fundamental timescale for decoherence and explores control techniques within a collective bosonic bath framework.

Findings

Coherence persists for small timescales but diminishes with larger ones.

A fundamental timescale $s$ governs the decoherence process.

$$-pulses can be used to manipulate decoherence effects.

Abstract

Within quantum information frameworks, managing decoherence stands as a pivotal task. The present work delves into decoherence dynamics of a dressed qubit, represented by a spinless fermion hopping between two lattice sites that are strongly coupled to a collective bosonic bath. To simplify calculations under strong coupling, we adopt the Lang-Firsov transformation, effectively minimizing system-bath interactions. Within the polaron perspective using Ohmic bath spectral density with a Gaussian cutoff, we identify a fundamental timescale $s$ (equivalently a length scale $l$), dictating coherence decay. Utilizing a quantum master equation in the energy eigen basis while maintaining fixed particle number, we demonstrate that coherence persists for small $s$ values but diminishes for larger ones. Additionally, we explore the utilization of $\pi$-pulses to manipulate decoherence within the system.