Direct observation of Hardy's paradox by joint weak measurement with an entangled photon pair

TL;DR

This paper experimentally demonstrates Hardy's paradox using joint weak measurements on entangled photon pairs, revealing the paradoxical nature of quantum mechanics directly through observed preposterous values.

Contribution

It presents the first direct observation of Hardy's paradox via joint weak measurement with entangled photons, providing new insights into quantum nonlocality.

Findings

Successfully measured paradoxical values in Hardy's experiment

Demonstrated the feasibility of joint weak measurement with entangled photons

Provided direct visual evidence of quantum nonlocality

Abstract

We implemented a joint weak measurement of the trajectories of two photons in a photonic version of Hardy's experiment. The joint weak measurement has been performed via an entangled meter state in polarization degrees of freedom of the two photons. Unlike Hardy's original argument in which the contradiction is inferred by retrodiction, our experiment reveals its paradoxical nature as preposterous values actually read out from the meter. Such a direct observation of a paradox will give us a new insight into the spooky action of quantum mechanics.