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Professor Shmuel Gurvitz Weizmann Institute of Science, Israel |
Abstract: The influence of the environment on a quantum system is mainly attributed to decoherence (dephasing), which destroys information, stored in the quantum system. However, the information is not totally lost but is hidden in the environment. It can be retrieved by a detector monitoring the environment. We investigate how such an information retrieval could influence decoherence of the quantum system. This is an issue of crucial importance in quantum cryptography, which relies on an assumption that one cannot make a measurement without perturbing the system. We demonstrate that this assumption is not always valid: one can gain information regarding the quantum system without increasing its decoherence rate, or even diminishing it. Besides its relevance for quantum cryptography, this result can be important for understanding quantum measurement and a role of information in quantum mechanics. A possible experimental realization is discussed.
About the Speaker: Prof. Shmuel Gurvitz obtained his Ph. D. from Institute of Theoretical and Experimental Physics. Then he immigrated to Israel and conducted research in Weizmann Institute of Science in 1972. He is now a Professor of Department of Particle Physics and Astrophysics in Weizmann Institute of Science. His research interests include Open systems, Quantum Measurements, Mesoscopic Physics, Tunneling, Scattering theory.
Date&Time: January 10, 2013 (Thursday), 14:00–15:00
Location: 606 Conference Room