Chin. Phys. B, 31, 017402 (2022)

Cross correlation mediated by distant Majorana zero modes with no overlap

 Lupei Qin, Wei Feng and Xin-Qi Li^†

Center for Joint Quantum Studies and Department of Physics, School of Science, Tianjin University, Tianjin 300072, China

* xinqi.li@dgquanwei.com

Abstract

Existing studies via shot noise calculation conclude that the cross correlation between the currents in the two leads connected by a pair of Majorana zero modes (MZMs) vanishes when their coupling energy ϵ_M→ 0. Motivated by the intrinsic nature of nonlocality of the MZMs, we revisit this important problem and propose an experimental scheme to demonstrate the nonvanishing cross correlation even at the limit ϵ_M→0. The proposed scheme employs the Andreevprocess-associated branch circuit currents, which are theoretically obtained by applying a decomposition analysis for the total currents while are accessible directly in practical measurement. For different bias voltage setup, we find intriguing results of both negative and positive correlations and carry out simple physical understanding using a quantum jump technique. Importantly, combining together with the evidence of the zero-bias-peak of conductance, the nonlocal cross correlation predicted in this work can help to confirm the existence of the nonlocal MZMs.