Update Oct14, 2011: The paper has appeared in the print version this month, Nature [...]]]> Our paper, Experimental investigation of the uncertainty principle in the presence of quantum memory and its application to witnessing entanglement, by Robert Prevedel, Deny Hamel, Roger Colbeck (Perimeter Institute), Kent Fisher, and Kevin Resch was published online today in Nature Physics.

Update Oct14, 2011: The paper has appeared in the print version this month, Nature Physics 7, 757 (2011).

Abstract: Strategies to optimally discriminate between quantum states are critical in quantum technologies. We present an experimental demonstration of minimum-error discrimination between [...]]]> Our paper Minimum-error discrimination of entangled quantum states by Yang Lu, Nick Coish, Rainer Kaltenbaek, Deny Hamel, Sarah Croke, and Kevin Resch was published today in Physical Review A.

Abstract: Strategies to optimally discriminate between quantum states are critical in quantum technologies. We present an experimental demonstration of minimum-error discrimination between entangled states, encoded in the polarization of pairs of photons. Although the optimal measurement involves projection onto entangled states, we use a result of J. Walgate et al. [Phys. Rev. Lett. 85, 4972 (2000)] to design an optical implementation employing only local polarization measurements and feed-forward, which performs at the Helstrom bound. Our scheme can achieve perfect discrimination of orthogonal states and minimum-error discrimination of nonorthogonal states.  Our experimental results show a definite advantage over schemes not using feed-forward.