Probing spin entanglement by gate-voltage-controlled interference of current correlation in quantum spin Hall insulators

TL;DR

This paper introduces a method to detect spin entanglement in quantum spin Hall insulators using gate-controlled interference in current correlations, enabling easy measurement of entanglement concurrence.

Contribution

It presents a novel entanglement detector based on interference effects in quantum spin Hall insulators with a side gate, incorporating spin dephasing effects.

Findings

Differential noise shows step structures indicating entanglement.

Concurrence can be extracted from noise measurements.

Method accounts for spin dephasing effects.

Abstract

We propose an entanglement detector composed of two quantum spin Hall insulators and a side gate deposited on one of the edge channels. For an ac gate voltage, the differential noise contributed from the entangled electron pairs exhibits the nontrivial step structures, from which the spin entanglement concurrence can be easily obtained. The possible spin dephasing effects in the quantum spin Hall insulators are also included.