Quantum Non-Locality in Systems with Open Boundaries: Failure of the Wigner-Function Formalism

TL;DR

This paper critically examines the Wigner-Function formalism for open quantum systems, revealing its limitations and non-physical predictions due to the non-local nature of quantum mechanics.

Contribution

It demonstrates that traditional boundary conditions in the Wigner formalism lead to non-physical results, highlighting the need for revised approaches in open quantum device modeling.

Findings

Conventional boundary schemes produce negative probabilities.

Application of the formalism can cause thermal injection of superpositions.

The non-locality of quantum mechanics conflicts with spatial separation assumptions.

Abstract

We shall revisit the conventional treatment of open quantum devices based on the Wigner-Function formalism. Our analysis will show that the artificial spatial separation between device active region and external reservoirs -properly defined within a semiclassical simulation scheme- is intrinsically incompatible with the non-local character of quantum mechanics. More specifically, by means of an exactly-solvable semiconductor model, we shall show that the application of the conventional boundary-condition scheme to the Wigner transport equation may produce highly non-physical results, like thermal injection of coherent state superpositions and boundary-driven negative probability distributions.