Quantum dynamics, dissipation, and asymmetry effects in quantum dot arrays

TL;DR

This paper investigates how dissipation, structural defects, and asymmetries influence the quantum dynamics of charge distribution in quantum dot arrays, highlighting temperature and phonon interactions' effects on system response.

Contribution

It introduces an open system approach to analyze the impact of asymmetries and electron-phonon interactions on quantum dot array dynamics, emphasizing the role of temperature and dissipation.

Findings

System response improves at low temperatures and weak phonon coupling.

Response deteriorates with increasing temperature and asymmetry.

Linear entropy analysis reveals the balance between coherence and dissipation.

Abstract

We study the role of dissipation and structural defects on the time evolution of quantum dot arrays with mobile charges under external driving fields. These structures, proposed as quantum dot cellular automata, exhibit interesting quantum dynamics which we describe in terms of equations of motion for the density matrix. Using an open system approach, we study the role of asymmetries and the microscopic electron-phonon interaction on the general dynamical behavior of the charge distribution (polarization) of such systems. We find that the system response to the driving field is improved at low temperatures (and/or weak phonon coupling), before deteriorating as temperature and asymmetry increase. In addition to the study of the time evolution of polarization, we explore the linear entropy of the system in order to gain further insights into the competition between coherent evolution and dissipative processes.