Experimental joint weak measurement on a photon pair as a probe of Hardy's Paradox

TL;DR

This paper experimentally performs joint weak measurements on photon pairs to explore Hardy's Paradox, revealing how weak probabilities can verify conflicting statements while resolving the paradox.

Contribution

It demonstrates the first experimental implementation of joint weak measurements on photon pairs to investigate quantum paradoxes like Hardy's Paradox.

Findings

Weak measurements verify conflicting statements in Hardy's Paradox

Weak probabilities resolve the paradoxical outcome

Experimental validation of joint weak measurement technique

Abstract

It has been proposed that the ability to perform joint weak measurements on post-selected systems would allow us to study quantum paradoxes. These measurements can investigate the history of those particles that contribute to the paradoxical outcome. Here, we experimentally perform weak measurements of joint (i.e. nonlocal) observables. In an implementation of Hardy's Paradox, we weakly measure the locations of two photons, the subject of the conflicting statements behind the Paradox. Remarkably, the resulting weak probabilities verify all these statements but, at the same time, resolve the Paradox.