Incoherence induced sign change in noise cross-correlations: A case study in the full counting statistics of a pure spin pump

TL;DR

This paper investigates how incoherence affects noise cross-correlations in a pure spin pump, revealing that incoherence can unexpectedly switch the sign of spin shot noise correlations, with implications for entanglement detection.

Contribution

It demonstrates that incoherence can invert the sign of spin shot noise cross-correlations in a non adiabatic pure spin pump, a novel insight into quantum noise behavior.

Findings

Incoherence can change the sign of spin shot noise cross-correlations from negative to positive.

The third moment of current fluctuations is less affected by incoherence.

Counterintuitive sign change indicates potential for entanglement detection.

Abstract

The full counting statistics of a non adiabatic pure spin pump are calculated with particular emphasis on the second and third moments. We show that incoherence can change the sign of spin shot noise cross-correlations from negative to positive, implying entanglement for spin-singlet electronic sources, a truly counterintuitive result. The third moment on the other hand is shown to be much more resilient to incoherence.