New Insight into Quantum Entanglement Using Weak Values

Shao-Jiang Du, Hairan Feng, Pengfei Zhang +2 more

Yinghua Ji, Yongmei Liu

Kazuhiro Yokota, Takashi Yamamoto, Masato Koashi +1 more

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 gives us new insights into the spooky action of quantum mechanics.

P. K. Aravind

Jeff Tollaksen, Debabrata Ghoshal

As a resource, quantum entanglement provides enormous power to quantum information processing and quantum communication. We focus on new properties of entanglement as revealed by quantum weak measurements. Weak measurements are performed between a pre-selected and post-selected states, one, or both or which are entangled.

Eliahu Cohen, Avshalom C. Elitzur

Quantum temporal peculiarities, involving ordinary and weak measurements, are explored. We introduce the foundations of weak measurement and outline some novel theoretical and experimental predictions derived from it. We then show how weak values, which explicitly depend on both forward and backward evolving state-vectors, can serve as important tools for gaining new insights into the nature of time.