Microwave spectroscopy of Majorana vortex modes

TL;DR

This paper proposes a microwave-based method to measure the topological quantum state of vortex-bound Majorana modes in superconductors, enabling non-local charge parity detection and quasiparticle lifetime measurement.

Contribution

It introduces a novel microwave resonator technique for dispersive readout of vortex Majorana parity, advancing topological qubit measurement methods.

Findings

Proposes a microwave resonator for charge parity readout of Majorana vortex pairs.

Enables measurement of vortex quasiparticle lifetimes beyond current STM capabilities.

Applicable to both topological and conventional superconductors.

Abstract

The observation of zero-bias conductance peaks in vortex cores of certain Fe-based superconductors has sparked renewed interest in vortex-bound Majorana states. These materials are believed to be intrinsically topological in their bulk phase, thus avoiding potentially problematic interface physics encountered in superconductor-semiconductor heterostructures. However, progress toward a vortex-based topological qubit is hindered by our inability to measure the topological quantum state of a non-local vortex Majorana state, i.e., the charge of a vortex pair. In this paper, we theoretically propose a microwave-based charge parity readout of the Majorana vortex pair charge. A microwave resonator above the vortices can couple to the charge allowing for a dispersive readout of the Majorana parity. Our technique may also be used in vortices in conventional superconductors and allows one to probe the lifetime of vortex-bound quasiparticles, which is currently beyond existing scanning tunneling microscopy capabilities.