Electron spin teleportation current through a quantum dot array operating in the stationary regime

TL;DR

This paper presents a detailed scheme for electron spin teleportation through a quantum dot array operating in a stationary regime, utilizing superconductors and entangled electron pairs to achieve steady-state teleportation current.

Contribution

It introduces a novel stationary regime teleportation protocol using quantum dots and superconductors, with a detailed theoretical analysis of the teleportation current and noise correlations.

Findings

Steady-state teleportation current correlates with Cooper pair current.

Teleportation is achieved without time-dependent gate voltages.

Noise correlations can diagnose successful teleportation.

Abstract

An electron spin state teleportation scheme is described in detail. It is based on the protocol by Bennett et al. [Phys. Rev. Lett. 70, 1895 (1993)], and involves the production and detection by superconductors of entangled pairs of electrons. Quantum dots filter individual electron transitions, and the whole teleportation sequence is selected in a five-dot cell by electrostatic gating in the stationary regime (no time dependent gate voltages): i) a normal dot carry the electron spin state to be teleported, two others carry the ancillary entangled pair; ii) two superconducting dots, coupled by a superconducting circuit, control the injection of the source electron and the detection of the teleported electron. This teleportation cell is coupled to emitter and receiver reservoirs. In a steady state, a spin-conserving current flows between the reservoirs, most exclusively carried by the teleportation channel. This current is perfectly correlated to a Cooper pair current flowing in the superconducting circuit, and which triggers detection of the teleported electron. This latter current indeed carries the classical information, which is necessary to achieve teleportation. The average teleportation current is calculated using the Bloch equations, for weakly coupled spin reservoirs. A diagnosis of teleportation is proposed using noise correlations.