Good evening,
Next week's seminar talk will be given by Wolfgang Tittel:
Tuesday, Dec. 7, 16.45, in HIT E 41.1 on Hoenggerberg. (Please note the exceptional location and time.)
Best regards, Stefan
______________________________________________________________________
Title: Broadband waveguide quantum memory for entangled photons
Abstract: The reversible transfer of quantum states of light in and out of matter constitutes an important building block for future applications of quantum communication: it allows synchronizing quantum information, and enables one to build quantum repeaters and quantum networks. Much effort has been devoted worldwide over the past years to develop memories suitable for the storage of quantum states. Of central importance to this task is the preservation of entanglement, a quantum mechanical phenomenon whose counter-intuitive properties have occupied philosophers, physicists and computer s cientists since the early days of quantum physics. Here we report, for the first time, the reversible transfer of photon-photon entanglement into entanglement between a photon and collective atomic excitation in a solid-state device. Towards this end, we employ a thulium-doped lithium niobate waveguide in conjunction with a photon-echo quantum memory protocol, and increase the spectral acceptance from the current maximum of 100 MHz to 5 GHz. The entanglement-preserving nature of our storage device is assessed by comparing Bell inequality violations as well as the amount of entanglement contained in the detected photon pairs before and after the reversible transfer, showing, within statistical error, a perfect mapping process. Our integrated, broadband quantum memory complements the family of robust, integrated lithium niobate devices. It renders frequency matching of light with matter interfaces in advanced applications of quantum communication simple and constitutes an important milestone on the path towards fully quantum-enabled networks.
Short Bio: Wolfgang Tittel studied Physics at the University of Frankfurt in Germany, was a Ph.D. student at the University of Geneva in Switzerland with Nicolas Gisin, and did post doctoral work at the University of Aarhus / Denmark and again in Geneva. He joined the Department of Physics and Astronomy and the Institute for Quantum Information Science at the University of Calgary as Associate Professor and NSERC/GDC/iCORE Industrial Research Chair in July 2006.
Dr. Tittel engaged in ground-breaking experiments in the field of quantum communication from the early stages on. The investigations were seminal in bringing quantum cryptography out of the laboratory and into the real world using a standard telecommunication fibre network, thereby raising both scientific and public awareness and appreciation that quantum technology is not restricted to contrived laboratory settings. His current interests include practical quantum cryptography, quantum relays, and quantum memory.
______________________________________________________________________