Realism and single-quanta nonlocality

TL;DR

This paper demonstrates that local realism cannot explain the quantum predictions for W states, which involve a single quantum shared among multiple qubits, due to interference effects with no classical counterpart.

Contribution

It reveals the fundamental incompatibility between local realism and quantum theory in the context of single-quanta shared states, highlighting a nonclassical interference phenomenon.

Findings

Local realism predictions conflict with quantum theory for W states.

Destructive interference of amplitude probabilities causes the incompatibility.

Nonlocal states exhibit interference effects without classical analogs.

Abstract

We show that local realism applied to states characterized by a single quanta equally and coherently shared between a number of qubits (so-called W states) produces predictions incompatible with quantum theory. The origin of this incompatibility is shown to originate from the destructive interference of amplitude probabilities associated with nonlocal states, a phenomenon that has no classical analog.