Emission of time-bin entangled particles into helical edge states

TL;DR

This paper introduces a novel single-particle source for helical edge states in quantum spin Hall insulators that can generate time-bin entangled electron pairs without breaking time-reversal symmetry, with potential applications in quantum information.

Contribution

It presents a new single-particle emitter design that produces time-bin entangled electrons in helical edge states, linking shot noise to entanglement concurrence.

Findings

The source can emit entangled electron pairs controllably.

Shot noise correlates with the entanglement quality.

The system operates without breaking time-reversal symmetry.

Abstract

We propose a single-particle source which emits into the helical edge states of a two-dimensional quantum spin Hall insulator. Without breaking time-reversal symmetry, this source acts like a pair of noiseless single-electron emitters which each inject separately into a chiral edge state. By locally breaking time-reversal symmetry, the source becomes a proper single-particle emitter which exhibits shot noise. Due to its intrinsic helicity, this system can be used to produce time-bin entangled pairs of electrons in a controlled manner. The shot noise created by the source is related to the concurrence of the emitted state.