The influence of ultra-fast laser pulses on electron transfer in molecular wires studied by a non-Markovian density matrix approach

TL;DR

This paper develops a non-Markovian density matrix approach to study how ultra-fast laser pulses influence electron transfer in molecular wires, revealing effects like tunneling suppression and current control.

Contribution

It introduces a non-perturbative quantum master equation framework for analyzing laser-driven electron transport in molecular wires, including short pulse effects.

Findings

Demonstrates coherent destruction of tunneling in driven systems

Shows laser pulses can suppress directed current

Analyzes electron dynamics under time-dependent fields

Abstract

New features of molecular wires can be observed when they are irradiated by laser fields. These effects can be achieved by periodically oscillating fields but also by short laser pulses. The theoretical foundation used for these investigations is a density matrix formalism where the full system is partitioned into a relevant part and a thermal fermionic bath. The derivation of a quantum master equation, either based on a time-convolutionless or time-convolution projection-operator approach, incorporates the interaction with time-dependent laser fields non-perturbatively and is valid at low temperatures for weak system-bath coupling. From the population dynamics the electrical current through the molecular wire is determined. This theory including further extensions is used for the determination of electron transport through molecular wires. As examples, we show computations of coherent destruction of tunneling in asymmetric periodically driven quantum systems, alternating currents and the suppression of the directed current by using a short laser pulse.