Experimental demonstration of the violation of the temporal Peres-Mermin inequality using contextual temporal correlations and noninvasive measurements

TL;DR

This paper demonstrates experimentally that quantum systems violate the Peres-Mermin inequality using non-invasive measurements on NMR qubits, highlighting contextual temporal correlations and their relation to Bell inequalities.

Contribution

It introduces a generalized quantum scattering circuit for non-invasive measurements and experimentally tests temporal non-contextual inequalities on an NMR quantum processor.

Findings

Violation of the Peres-Mermin inequality demonstrated

Experimental evidence of the temporal KCBS inequality violation

Tsirelson bound matches the spatial Bell inequality bound

Abstract

We present a generalized quantum scattering circuit which can be used to perform non-invasive quantum measurements, and implement it on NMR qubits. Such a measurement is a key requirement for testing temporal non-contextual inequalities. We use this circuit to experimentally demonstrate the violation of the Peres-Mermin inequality (which is the temporal analog of a Klyachko-Can- Binicioglu-Shumovsky (KCBS) inequality), on a three-qubit NMR quantum information processor. Further, we experimentally demonstrate the violation of a transformed Bell-type inequality (the spatial equivalent of the temporal KCBS inequality) and show that its Tsirelson bound is the same as that for the temporal KCBS inequality. In the temporal KCBS scenario, the contextual bound is strictly lower than the quantum temporal and nonlocal bounds.