Detecting Majorana fermions by use of superconductor-quantum Hall liquid junctions

TL;DR

This paper theoretically investigates tunneling between topological superconductors and quantum Hall liquids, proposing conductance signatures as definitive evidence for Majorana fermions, with implications for experimental detection.

Contribution

It introduces a theoretical framework for detecting Majorana fermions via tunneling conductance in superconductor-quantum Hall junctions, highlighting universal signatures for different quantum Hall states.

Findings

Universal conductance of 2e^2/h for integer QH liquids indicating Majorana fermions.

Vanishing zero-bias conductance for fractional QH liquids with bias-dependent behavior.

Theoretical predictions are experimentally accessible with current technology.

Abstract

The point contact tunnel junctions between a one-dimensional topological superconductor and single-channel quantum Hall (QH) liquids are investigated theoretically with bosonization technology and renormalization group methods. For the $\nu=1$ integer QH liquid, the universal low-energy tunneling transport is governed by the perfect Andreev reflection fixed point with quantized zero-bias conductance $G(0)=2e^{2}/h$, which can serve as a definitive fingerprint of the existence of a Majorana fermion. For the $\nu =1/m$ Laughlin fractional QH liquids, its transport is governed by the perfect normal reflection fixed point with vanishing zero-bias conductance and bias-dependent conductance $G(V) \sim V^{m-2}$. Our setup is within reach of present experimental techniques.