Decoherence of Einstein-Podolsky-Rosen pairs in a noisy Andreev entangler

TL;DR

This paper studies how quantum noise affects the transport of nonlocal Cooper pairs in a realistic Andreev entangler setup, revealing the impact of voltage fluctuations on entanglement and transport efficiency.

Contribution

It analyzes the decoherence effects caused by quantum noise in a practical Andreev entangler, extending prior idealized models to include realistic noise sources.

Findings

Quantum noise reduces the efficiency of nonlocal Cooper pair transport.

Voltage fluctuations induce decoherence, affecting entanglement quality.

The study quantifies the impact of resistive leads on entanglement transport.

Abstract

We investigate quantum noise effect on the transportation of nonlocal Cooper pairs accross the realistic Andreev entangler which consists of an s-wave superconductor coupled to two small quantum dots at resonance which themselves are coupled to normal leads. The noise emerges due to voltage fluctuations felt by the electrons residing on the two dots as a result of the finite resistances in the gate leads or of any resistive lead capacitively coupled to the dots. In the ideal noiseless case, the setup provides a trustable source of mobile and nonlocal spin-entangled electrons and the transport is dominated by a two-particle Breit-Wigner resonance that allows the injection of two spin-entangled electrons into different leads at the same energy [P. Recher, E. V. Sukhorukov, and D. Loss, Phys. Rev. B 63, 165314 (2001)]. We seek to revisit the transport of those nonlocal Cooper pairs as well as the efficiency of such an Andreev entangler when including the quantum noise (decoherence).