BITLLES: Electron Transport Simulation with Quantum Trajectories

TL;DR

The paper introduces BITLLES, a quantum electron transport simulation tool based on Bohmian trajectories, extending classical Monte Carlo methods to accurately model dynamic quantum behaviors like AC response and noise.

Contribution

It presents a novel Monte Carlo algorithm leveraging Bohmian mechanics for efficient quantum transport simulation in open systems, improving accuracy over traditional semi-classical methods.

Findings

Provides a quantitative description of quantum electron transport.

Extends classical Monte Carlo techniques to the quantum regime.

Offers a free, open-source software tool for advanced simulations.

Abstract

After the seminal work of R. Landauer in 1957 relating the electrical resistance of a conductor to its scattering properties, much progress has been made in our ability to predict the performance of electron devices in the DC (stationary) regime. Computational tools to describe their dynamical behavior (including the AC, transient and noise performance), however, are far from being as trustworthy as would be desired by the electronic industry. While there is no fundamental limitation to correctly modeling the high-frequency quantum transport and its fluctuations, certainly more careful attention must be paid to delicate issues such as overall charge neutrality, total current conservation, or the back action of the measuring apparatus. In this review, we will show how the core ideas behind the Bohmian formulation of quantum mechanics can be exploited to design an efficient Monte Carlo algorithm that provides a quantitative description of electron transport in open quantum systems. By making the most of trajectory-based and wave function methods, the BITLLES simulator, a free software developed by the authors, extends the capabilities that the semi-classical Monte Carlo simulation technique has offered for decades (DC, AC, noise, transients) to the quantum regime.