Detecting a quantum critical point in topological SN junctions

TL;DR

This paper proposes an experimental approach to detect a quantum critical point in topological superconductor junctions formed by spin-orbit coupled wires, highlighting its robustness against disorder.

Contribution

It introduces a method to observe the quantum critical point in a single quantum wire, extending previous two-channel models to a more practical single-channel setup.

Findings

The critical point can be accessed experimentally in a single wire.

The critical point shows resilience to disorder.

The approach simplifies detection of topological quantum phase transitions.

Abstract

A spin-orbit coupled quantum wire, with one end proximate to an s-wave superconductor, can become a topological superconductor, with a Majorana mode localized at each end of the superconducting region. It was recently shown that coupling one end of such a topological superconductor to $two$ normal channels of interacting electrons leads to a novel type of frustration and a quantum critical point when both channels couple with equal strength. We propose an experimental method to access this critical point in a $single$ quantum wire and show its resilience to disorder.