Formal equivalence between partitioned and partition-free quenches in quantum transport

TL;DR

This paper establishes a formal equivalence between partitioned and partition-free approaches in quantum transport, extending previous static bias results to dynamic biases and complex molecular structures using non-equilibrium Green's functions.

Contribution

It derives a general formal equivalence between two quantum transport calculation methods for time-dependent biases and large molecular systems.

Findings

Equivalence holds for arbitrary time-dependent biases

Extends previous static bias results to dynamic cases

Clarifies the relationship between two theoretical approaches

Abstract

In this paper we review the partitioned and partition-free approaches to the calculation of the time-dependent response of a molecular junction to the switch-on of an arbitrary time-dependent bias. Using the non equilibrium Green's function formalism on different time contours, we derive a formal equivalence between these two approaches. This clarifies a recent result of [PRB 95, 104301 (2017)], which is valid for a static bias and single level molecular structure, and extends it to arbitrary time-dependent biases and arbitrarily large molecular structures.