The Effect of Decoherence on the Contextual and Nonlocal Properties of a Biphoton

TL;DR

This paper experimentally examines how decoherence affects the quantum contextuality and nonlocality of biphotons, revealing that contextuality is more sensitive to noise than nonlocality.

Contribution

It adapts the KCBS inequality test for biphotons in realistic scenarios and compares the robustness of contextuality and nonlocality under decoherence.

Findings

Contextuality is more fragile to noise than nonlocality.

Biphotons can exhibit both contextuality and nonlocality under controlled conditions.

Decoherence impacts quantum properties differently, affecting quantum information tasks.

Abstract

Quantum contextuality is a nonintuitive property of quantum mechanics, that distinguishes it from any classical theory. A complementary quantum property is quantum nonlocality, which is an essential resource for many quantum information tasks. Here we experimentally study the contextual and nonlocal properties of polarization biphotons. First, we investigate the ability of the biphotons to exhibit contextuality by testing the violation of the KCBS inequality. In order to do so, we used the original protocol suggested in the KCBS paper, and adjusted it to the real scenario, where some of the biphotons are distinguishable. Second, we transmitted the biphotons through different unital channels with controlled amount of noise. We measured the decohered output states, and demonstrated that the ability to exhibit quantum contextuality using the KCBS inequality is more fragile to noise than the ability to exhibit nonlocality.