Realistic operation of an entangler : a density matrix approach

TL;DR

This paper models a superconductor-based electron spin entangler using density matrix equations, analyzing coherent tunneling and parasitic effects to optimize its operation.

Contribution

It introduces a non-perturbative density matrix approach to study the detailed operation and parasitic effects in a superconductor-based electron spin entangler.

Findings

Optimal device operation conditions identified

Parasitic effects like cotunneling quantified

Coherent tunneling effects incorporated in model

Abstract

The detailed operation of an electron spin entangler is studied, using density matrix equations. The device is made of a superconductor, two quantum dots and two normal leads. The treatment takes into account coherent tunneling in a non-perturbative way, and analyzes the various parasitic effects, in addition to the main process (crossed Andreev reflection) : those include singlet pairs passing through a single dot, or cotunneling between dots through the superconductor. The optimum operation of the device is characterized.