The topological Kondo model out of equilibrium

TL;DR

This paper investigates the out-of-equilibrium behavior of the topological Kondo effect in Majorana-based systems, revealing the crossover to the strongly correlated regime and universal conductance features using advanced simulation techniques.

Contribution

It introduces a nonperturbative simulation approach to study the dynamics and transport properties of topological Kondo systems out of equilibrium.

Findings

Determines the Kondo temperature via Majorana magnetization relaxation.

Shows the onset of electric transport after a quantum quench.

Provides evidence of universal fractional zero-bias conductance.

Abstract

The topological Kondo effect is a genuine manifestation of the nonlocality of Majorana modes. We investigate its out-of-equilibrium signatures in a model with a Cooper-pair box hosting four of these topological modes, each connected to a metallic lead. Through an advanced matrix-product-state approach tailored to study the dynamics of superconductors, we simulate the relaxation of the Majorana magnetization, which allows us to determine the related Kondo temperature, and we analyze the onset of electric transport after a quantum quench of a lead voltage. Our results apply to Majorana Cooper-pair boxes fabricated in double nanowire devices and provide nonperturbative evidence of the crossover from weak-coupling states to the strongly correlated topological Kondo regime. The latter dominates at the superconductor charge degeneracy points and displays the expected universal fractional zero-bias conductance.