Quantum Mechanics and Leggett's Inequalities

TL;DR

This paper demonstrates that using the density matrix description for entangled photons or spin-1/2 particles shows that quantum mechanics does not violate Leggett's inequalities, challenging previous assumptions.

Contribution

It provides a new perspective on the violation of Leggett's inequalities by quantum mechanics using the density matrix formalism.

Findings

Leggett's inequality is not violated by quantum mechanics when using the density matrix approach.

Challenges previous results suggesting violations of Leggett's inequalities.

Highlights the importance of the proper description of quantum states in such tests.

Abstract

We show that when the proper description of the behaviour of individual photons or spin 1/2 particles in a spherically symmetric entangled pair is done through the use of the density matrix, the Leggett's inequality is not violated by quantum mechanics.