Noise of Entangled Electrons: Bunching and Antibunching

TL;DR

This paper investigates how electron-electron interactions affect entangled electron states in conductors, revealing that singlet states exhibit bunching noise while triplet states show antibunching, with implications for quantum communication.

Contribution

It introduces an interference experiment setup to analyze entangled electrons in a Fermi liquid, quantifies the impact of interactions on entanglement fidelity, and characterizes noise behavior for singlet and triplet states.

Findings

Fidelity of entangled states is reduced by electron interactions.

Singlet states show enhanced bunching noise (Fano factor doubled).

Triplet states exhibit antibunching with reduced noise.

Abstract

Addressing the feasibility of quantum communication with entangled electrons in an interacting many-body environment, we propose an interference experiment using a scattering set-up with an entangler and a beam splitter. It is shown that, due to electron-electron interaction, the fidelity of the entangled singlet and triplet states is reduced by z_F^2 in a conductor described by Fermi liquid theory. We calculate the quasiparticle weight factor z_F for a two-dimensional electron system. The current noise for electronic singlet states turns out to be enhanced (bunching behavior), while it is reduced for triplet states (antibunching). Within standard scattering theory, we find that the Fano factor (noise-to-current ratio) for singlets is twice as large as for independent classical particles and is reduced to zero for triplets.