The Interplay of Spin and Charge Channels in Zero Dimensional Systems

TL;DR

This paper provides a quantum mechanical analysis of how charge and spin interactions in quantum dots influence phenomena like Coulomb blockade suppression and spin susceptibility enhancement, especially near instabilities.

Contribution

It introduces a non-perturbative framework using gauge bosons to describe charge and spin zero-mode interactions in quantum dots.

Findings

Spin fluctuations suppress Coulomb blockade.

Charge and spin interactions lead to non-monotonic behavior.

Enhanced dynamic spin susceptibility near instabilities.

Abstract

We present a full fledged quantum mechanical treatment of the interplay between the charge and the spin zero-mode interactions in quantum dots. Quantum fluctuations of the spin-mode suppress the Coulomb blockade and give rise to non-monotonic behavior near this point. They also greatly enhance the dynamic spin susceptibility. Transverse fluctuations become important as one approaches the Stoner instability. The non-perturbative effects of zero-mode interaction are described in terms of charge (U(1)) and spin (SU(2)) gauge bosons.