Generating distributed entanglement from electron currents

TL;DR

This paper proposes a passive solid-state device that converts spin-entangled electron currents into distributed static entanglement, enabling long-distance quantum correlations with robustness to decoherence.

Contribution

It introduces a novel method to generate distributed static entanglement from flying qubits using a passive device with weak Coulomb interactions.

Findings

Entanglement can be generated from electron currents in a passive device.

The generated static entanglement is robust against decoherence.

Spatial separation of entangled pairs exceeds tunneling-based methods.

Abstract

Several recent experiments have demonstrated the viability of a passive device that can generate spin-entangled currents in two separate leads. However, manipulation and measurement of individual flying qubits in a solid state system has yet to be achieved. This is particularly difficult when a macroscopic number of these indistinguishable qubits are present. In order to access such an entangled current resource, we therefore show how to use it to generate distributed, static entanglement. The spatial separation between the entangled static pair can be much higher than that achieved by only exploiting the tunnelling effects between quantum dots. Our device is completely passive, and requires only weak Coulomb interactions between static and flying spins. We show that the entanglement generated is robust to decoherence for large enough currents.