Probing the non-locality of Majorana fermions via quantum correlations

TL;DR

This paper proposes a novel method using quantum discord to detect the non-locality of Majorana fermions in solid-state systems, offering a new way to identify and study Majorana bound states experimentally.

Contribution

It introduces a quantum correlation-based approach, specifically quantum discord, to probe the intrinsic non-locality of Majorana fermions in nanowire systems, distinguishing them from regular fermions.

Findings

Quantum discord reveals non-local correlations of Majorana fermions.

Without tunnel coupling, entanglement is absent but discord persists.

Proposed experimental setup to measure quantum discord as a signature.

Abstract

Majorana fermions (MFs) are exotic particles that are their own anti-particles. Recently, the search for the MFs occurring as quasi-particle excitations in solid-state systems has attracted widespread interest, because of their fundamental importance in fundamental physics and potential applications in topological quantum computation based on solid-state devices. Here we study the quantum correlations between two spatially separate quantum dots induced by a pair of MFs emerging at the two ends of a semiconductor nanowire, in order to develop a new method for probing the MFs. We find that without the tunnel coupling between these paired MFs, quantum entanglement cannot be induced from an unentangled (i.e., product) state, but quantum discord is observed due to the intrinsic nonlocal correlations of the paired MFs. This finding reveals that quantum discord can indeed demonstrate the intrinsic non-locality of the MFs formed in the nanowire. Also, quantum discord can be employed to discriminate the MFs from the regular fermions. Furthermore, we propose an experimental setup to measure the onset of quantum discord due to the nonlocal correlations. Our approach provides a new, and experimentally accessible, method to study the Majorana bound states by probing their intrinsic non-locality signature.