Signatures of Non-Abelian Kitaev quantum spin liquids in noise magnetormetry

TL;DR

This paper proposes using noise magnetometry with NV centers to detect Majorana zero modes in non-Abelian Kitaev quantum spin liquids, providing a potential method to identify non-Abelian phases in such materials.

Contribution

It introduces a novel approach using $T_1$-based noise magnetometry to detect signatures of Majorana fermions in Kitaev quantum spin liquids, which is robust against fluctuations.

Findings

$1/T_1$ increases when NV center frequency matches MZM energy difference.

External Zeeman field tunes the MZM energy difference.

Spectrum robustness due to large excitation gap of $Z_2$ gauge field.

Abstract

Identification of isolated Majorana zero modes (MZMs) is a key step towards the realization of fault-tolerant topological quantum computation. Here we show how the $T_1$-based noise magnetormetry of a nitrogen-vacancy (NV) center qubit can reveal the unique signatures of Majorana fermions attached to vacancies in a non-Abelian Kitaev quantum spin liquid (KQSL). The $1/T_1$ of the NV center is found to be increased significantly when the working frequency of the NV center matches the energy difference between a MZM and a low-energy hybridized mode involving dangling Majorana fermions adjacent to vacancies. In experiments, this energy difference can be tuned by an external Zeeman field. Because of the large excitation gap of flipping a local $Z_2$ gauge field, the $1/T_1$ spectrum is robust against other fluctuations in KQSLs. Our study presents a promising pathway for identifying the non-Abelian phase in Kitaev materials.