Decoherence of a quantum magneto-oscillator : Effect of field-bath interaction

This study investigates the quantum dissipative dynamics of a charged magneto-oscillator (CMO) interacting with a heat bath of harmonic oscillators. While standard models of quantum Brownian motion typically focus on direct system-bath coupling, this paper introduces an additional 'field-bath' interaction, where the external confining potential influences the bath particles. The authors employ the generalized quantum Langevin equation and a non-Markovian master equation to derive the system's dynamics, focusing on how this tunable interaction (governed by a parameter lambda) affects decoherence and correlation functions.

The researchers find that the field-bath interaction significantly impacts the system's dissipative response. Specifically, the interaction modifies the effective spring constant of the CMO and alters the memory kernel of the environment. Numerical analysis of position and velocity autocorrelation functions reveals that increasing the coupling parameter lambda leads to faster damping of these correlations. Furthermore, the study shows that the off-diagonal elements of the reduced density matrix decay more rapidly as the field-bath interaction strength increases, indicating an enhanced decoherence rate. The authors also provide an experimental proposal to test these theoretical predictions, emphasizing the importance of reservoir engineering in quantum technologies.

Understanding the mechanisms of decoherence is fundamental to the development of quantum technologies, where maintaining quantum superposition is critical. By showing that the interaction between an external field and the environment can be tuned to control decoherence, this work offers a new mechanism for reservoir engineering. It provides a more realistic physical description of charged particles in magnetic fields, bridging the gap between theoretical quantum Brownian motion models and complex molecular dynamics simulations.