Southwest Quantum Information and Technology

Traffic on the quantum highway: The direct path may not be the shortest

Presenting Author: Shahabeddin Aslamarand, Florida Atlantic University
Contributing Author(s): Razaei,Tahereh / Miller,Warner A. / Snyder,Robert / Khajavi,Behzad / Fanto,Michael / Alsing,Paul M. / Ahn,Doyeol

Quantum mechanics can produce correlations that are much stronger than classically allowed. Quantum entanglement is recognized as the key resource for quantum computers, and this stronger–than–classical correlation is the “fuel” for the quantum computing highway. Much attention has been placed on entanglement and in defining a proper measure of entanglement. This is still an active field of research. In 1991 Schumacher forwarded a beautiful geometric approach to this problem for a maximally entangled two-qubit state. His approach used a well–established information distance that depended on measurements made on an ensemble of identical singlet states. He calculated that for specific detector settings used to measure each of the two entangled states, that the resulting geometry violated a triangle inequality even though classically, this was not possible. This is an information geometric Bell inequality. Here we experimentally-reproduce his construction and demonstrate a definitive violation for a singlet state of two photons, |ψi = (|00i + |11i)/√2, based on coincidence counting of photons produced in the laboratory by the usual spontaneous parametric down-conversion in a paired BBO crystal configuration. The singlet states we produced have fidelities of ∼91 percent based on our tomographic measurements. We discussgeneralizations to higher dimensional multipartite quantum states.

(Session 5 : Saturday from 5:00pm - 7:00pm)