  We experimentally demonstrate the superior discrimination of separated,
unentangled two-qubit correlated states using nonlocal measurements, when
compared with measurements based on local operations and classical
communications. When predicted theoretically, this phenomenon was dubbed
"quantum nonlocality without entanglement." We characterize the performance of
the nonlocal, or joint, measurement with a payoff function, for which we
measure 0.72(2), compared with the maximum locally achievable value of 2/3 and
the overall optimal value of 0.75.
