Strong Charge Fluctuations in the Single-Electron Box: A Quantum Monte Carlo Analysis

TL;DR

This paper uses quantum Monte Carlo simulations to analyze strong electron tunneling in a single-electron box, providing detailed results on free energy and charge behavior across various tunneling strengths.

Contribution

It offers new, comprehensive quantum Monte Carlo data on the single-electron box at arbitrary tunneling strengths, clarifying previous theoretical controversies.

Findings

Effective charging energy for strong tunneling matches some theoretical predictions.

Charge on the island varies with external bias voltage, consistent with quantum Monte Carlo results.

Results extend understanding of electron tunneling in nanoscale systems.

Abstract

We study strong electron tunneling in the single-electron box, a small metallic island coupled to an electrode by a tunnel junction, by means of quantum Monte Carlo simulations. We obtain results, at arbitrary tunneling strength, for the free energy of this system and the average charge on the island as a function of an external bias voltage. In much of the parameter range an extrapolation to the ground state is possible. Our results for the effective charging energy for strong tunneling are compared to earlier -- in part controversial -- theoretical predictions and Monte Carlo simulations.