Finite-temperature Bell test for quasiparticle entanglement in the Fermi sea

TL;DR

This paper shows that finite temperature prevents Bell tests in most electronic setups for quasiparticle entanglement, but proposes a resonant detection method to overcome this and identify the critical temperature for entanglement.

Contribution

It introduces a novel resonant detection strategy that enables Bell tests at finite temperatures in solid-state systems, overcoming previous fundamental limitations.

Findings

Finite temperature hinders Bell tests in electronic setups.

Resonant coupling detection strategy overcomes quasiparticle emission issues.

Method allows determination of critical temperature for entanglement.

Abstract

We demonstrate that the Bell test cannot be realized at finite temperatures in the vast majority of electronic setups proposed previously for quantum entanglement generation. This fundamental difficulty is shown to originate in a finite probability of quasiparticle emission from Fermi-sea detectors. In order to overcome the feedback problem, we suggest a detection strategy, which takes advantage of a resonant coupling to the quasiparticle drains. Unlike other proposals, the designed Bell test provides a possibility to determine the critical temperature for entanglement production in the solid state.