Dynamical control of correlated states in a square quantum dot

TL;DR

This paper explores how oscillatory electric fields can control the dynamics of two-electron Wigner molecules in square quantum dots, revealing conditions to suppress tunneling and enabling manipulation of entangled states.

Contribution

It introduces an effective Hubbard-type model to analyze field-driven control of correlated electron states and provides analytic formulas for anti-crossings in the Floquet spectrum.

Findings

Tunneling can be strongly quenched at specific field parameters.

Analytic expressions for anti-crossings enable experimental parameter measurement.

Potential for controlling entangled states in mesoscopic devices.

Abstract

In the limit of low particle density, electrons confined to a quantum dot form strongly correlated states termed Wigner molecules, in which the Coulomb interaction causes the electrons to become highly localized in space. By using an effective model of Hubbard-type to describe these states, we investigate how an oscillatory electric field can drive the dynamics of a two-electron Wigner molecule held in a square quantum dot. We find that, for certain combinations of frequency and strength of the applied field, the tunneling between various charge configurations can be strongly quenched, and we relate this phenomenon to the presence of anti-crossings in the Floquet quasi-energy spectrum. We further obtain simple analytic expressions for the location of these anti-crossings, which allows the effective parameters for a given quantum dot to be directly measured in experiment, and suggests the exciting possibility of using ac-fields to control the time evolution of entangled states in mesoscopic devices.