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
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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.
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