Correlated charge polarization in a chain of coupled quantum dots

TL;DR

This paper investigates charge polarization in a linear array of coupled quantum dots, revealing universal scaling in the insulating phase and quantized polarization in the metallic phase through Bethe ansatz analysis.

Contribution

It introduces a detailed analysis of charge polarization mechanisms in quantum dot chains using the Bethe ansatz, highlighting distinct processes in metallic and insulating phases.

Findings

Charge polarization occurs via bound states in the metallic phase.

In the Mott-insulating phase, polarization involves superpositions of antibound states.

Polarizability shows universal scaling in the insulating phase.

Abstract

Coherent charge transfer in a linear array of tunnel-coupled quantum dots, electrostatically coupled to external gates, is investigated using the Bethe ansatz for a symmetrically biased Hubbard chain. Charge polarization in this correlated system is shown to proceed via two distinct processes: formation of bound states in the metallic phase, and charge transfer processes corresponding to a superposition of antibound states at opposite ends of the chain in the Mott-insulating phase. The polarizability in the insulating phase of the chain exhibits a universal scaling behavior, while the polarization charge in the metallic phase of the model is shown to be quantized in units of $e/2$.