A junction of three quantum wires: restoring time-reversal symmetry by interaction

TL;DR

This paper studies how interactions affect electron transport in a three-wire quantum junction with magnetic flux, revealing stable conductance states and the impact of interaction type on symmetry and conductance.

Contribution

It provides a comprehensive analysis of conductance flow in a three-wire quantum junction considering interactions and magnetic flux, identifying stable fixed points and their properties.

Findings

Attractive interactions lead to a stable asymmetric conductance fixed point.

Repulsive interactions exhibit a line of stable fixed points with zero conductance.

Symmetric conductance fixed points (4/9 e^2/h) are stable under certain conditions.

Abstract

We investigate transport of correlated fermions through a junction of three one-dimensional quantum wires pierced by a magnetic flux. We determine the flow of the conductance as a function of a low-energy cutoff in the entire parameter space. For attractive interactions and generic flux the fixed point with maximal asymmetry of the conductance is the stable one, as conjectured recently. For repulsive interactions and arbitrary flux we find a line of stable fixed points with vanishing conductance as well as stable fixed points with symmetric conductance (4/9)(e^2/h).