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

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.