High-Visibility Time-Bin Entanglement for Testing Chained Bell Inequalities

TL;DR

This paper demonstrates how to achieve high-visibility time-bin entanglement necessary for violating chained Bell inequalities, addressing the loophole issues in energy-time entanglement experiments.

Contribution

It presents a method to reach over 94.63% visibility in time-bin entangled states for chained Bell inequality tests with 6, 8, and 10 terms.

Findings

Achieved high visibility (>94.63%) in time-bin entanglement.

Successfully violated chained Bell inequalities with multiple terms.

Addresses loophole issues in energy-time entanglement experiments.

Abstract

The violation of Bell's inequality requires a well-designed experiment to validate the result. In experiments using energy-time and time-bin entanglement, initially proposed by Franson in 1989, there is an intrinsic loophole due to the high postselection. To obtain a violation in this type of experiment, a chained Bell inequality must be used. However, the local realism bound requires a high visibility in excess of 94.63 percent in the time-bin entangled state. In this work, we show how such a high visibility can be reached in order to violate a chained Bell inequality with 6, 8 and 10 terms.