Experimental demonstration of nonlocal effects of the partial collapse measurement and reversal process

TL;DR

This paper experimentally demonstrates the nonlocal reversal of a partial-collapse quantum measurement on entangled photons, using linear optics, and verifies the nonlocality through Bell inequality tests, contributing to quantum communication and error correction.

Contribution

It presents the first experimental realization of nonlocal reversal of partial measurements on entangled photons using linear optics.

Findings

Successful reversal of partial measurement demonstrated

Reconstructed states confirmed via quantum state tomography

Nonlocality verified through Bell inequality violation

Abstract

We experimentally demonstrate the nonlocal reversal of a partial-collapse quantum measurement on two-photon entangled state. Both the partial measurement and the reversal operation are implemented in linear optics with two displaced Sagnac interferometers, which are characterized by single qubit quantum process tomography. The recovered state is measured by quantum state tomography and its nonlocality is characterized by testing the Bell inequality. Our result will be helpful in quantum communication and quantum error correction.