Effects of measurement dependence on 1-parameter family of Bell tests

TL;DR

This paper investigates how relaxing measurement independence assumptions affects Bell tests, revealing the relationship between measurement dependence, Eve's guessing probability, and the maximum correlation achievable, with implications for quantum security.

Contribution

It introduces a detailed analysis of measurement dependence effects on 1-parameter Bell tests, including strategies for Eve and comparisons with Chain inequalities.

Findings

Eve's maximum faking strategy is characterized.

Range of parameters where 1-PFB is more secure than Chain inequality.

Relationship established among measurement dependence, guessing probability, and correlation bounds.

Abstract

Most quantum information tasks based on Bell tests relie on the assumption of measurement independence. However, it is difficult to ensure that the assumption of measurement independence is always met in experimental operations, so it is crucial to explore the effects of relaxing this assumption on Bell tests. In this paper, we discuss the effects of relaxing the assumption of measurement independence on 1-parameter family of Bell (1-PFB) tests. For both general and factorizable input distributions, we establish the relationship among measurement dependence, guessing probability, and the maximum value of 1-PFB correlation function that Eve can fake. The deterministic strategy when Eve fakes the maximum value is also given. We compare the unknown information rate of Chain inequality and 1-PFB inequality, and find the range of the parameter in which it is more difficult for Eve to fake the maximum quantum violation in 1-PFB inequality than in Chain inequality.