Dissipation-induced quantum phase transition in a quantum box

TL;DR

This paper investigates how dissipation influences quantum phase transitions in a quantum box, showing that strong dissipation can restore Coulomb blockade steps by suppressing charge fluctuations.

Contribution

It provides a detailed analysis of the dissipation-induced quantum phase transition using bosonization and numerical renormalization group methods.

Findings

Dissipation can induce a quantum phase transition in a quantum box.

Strong dissipation suppresses charge fluctuations and restores Coulomb blockade.

The study employs bosonization and NRG techniques to analyze the transition.

Abstract

In a recent work, Le Hur has shown that dissipative coupling to gate electrodes may play an important role in a quantum box near its degeneracy point [K. Le Hur, Phys. Rev. Lett. {\bf 92}, 196804 (2004)]: While quantum fluctuations of the charge of the dot tend to round Coulomb blockade charging steps of the box, strong enough dissipation suppresses these fluctuations and leads to the reappearance of sharp charging steps. In the present paper we study this quantum phase transition in detail using bosonization and numerical renormalization group methods in the limit of vanishing level spacing.