Testing local-realism and macro-realism under generalized dichotomic measurements

TL;DR

This paper explores how the combination of measurement sharpness and biasedness affects the ability to test violations of local-realism and macro-realism, revealing a trade-off and greater robustness in macro-realism tests.

Contribution

It introduces an analysis of the combined effects of biasedness and sharpness parameters in generalized quantum measurements on LR and MR violations.

Findings

Trade-off between biasedness and sharpness in probing LR and MR.

Robustness of the trade-off is greater in macro-realism tests.

Measurement parameters influence the detectability of quantum nonlocality.

Abstract

Generalised quantum measurements with two outcomes are fully characterised by two real parameters, dubbed as sharpness parameter and biasedness parameter and they can be linked with different aspects of the experimental setup. It is known that precision of measurements, characterised by the sharpness parameter of the measurements, reduces the possibility of probing quantum features like violation of local-realism (LR) or macro-realism (MR). Here we investigate the effect of biasedness together with sharpness of measurement and find a trade-off between those two parameters in the context of probing violation of LR and MR. Interestingly we also find the above mentioned trade-off is more robust in the later case.