Emission of entangled Kramers pairs from a helical mesoscopic capacitor

TL;DR

This paper proposes a novel mesoscopic capacitor in topological insulators that emits entangled electron pairs, with high efficiency and potential for quantum information applications, analyzed through entanglement measures and noise experiments.

Contribution

It introduces a new entangled electron pair source using a driven antidot coupled to both edges of a topological insulator, enabling high-efficiency entanglement generation.

Findings

High emission efficiency ($  50 ext{%}$) even for maximally entangled states.

The emitted entangled states can be characterized by concurrence and tested via noise and Bell inequality violations.

The device exploits spin-momentum locking in topological insulators for entanglement generation.

Abstract

The realization of single-electron sources in integer quantum Hall systems has paved the way for exploring electronic quantum optics experiments in solid-state devices. In this work, we characterize a single Kramers pair emitter realized by a driven antidot embedded in a two-dimensional topological insulator, where spin-momentum locked edge states can be exploited for generating entanglement. Contrary to previous proposals, the antidot is coupled to both edges of a quantum spin Hall bar, thus enabling this mesoscopic capacitor to emit an entangled two-electron state. We study the concurrence $\mathcal{C}$ of the emitted state and the efficiency $\mathcal{F}$ of its emission as a function of the different spin-preserving and spin-flipping tunnel couplings of the antidot with the edges. We show that the efficiency remains very high ($\mathcal{F}\geq 50\%$) even for maximally entangled states ($\mathcal{C}=1$). We also discuss how the entanglement can be probed by means of noise measurements and violation of the Clauser-Horne-Shimony-Holt inequality.