Vortrag: Quantum Memories for Quantum Networks, 19.06.2009, 11:00 Uhr

16 Jun 2009 by in Studium

Im Rahmen des Berufungsverfahrens für die Professur aus Angewandter Quantenphysik hält Hugues de Riedmatten von der Group of Applied Physics-Optics, University of Geneva einen Vortrag mit dem Titel "Quantum Memories for Quantum Networks".

Dieser Vortrag findet am Freitag, 19.06.2009 um 11:00 Uhr im Hörsaal des Atominstituts der österreichischen Universitäten (Stadionallee 2, 1020 Wien) statt.


Quantum networks hold the promise for revolutionary advances in information processing with
quantum resources distributed over remote locations via quantum-repeater architectures [1].
Quantum networks are composed of nodes for storing and processing quantum states, and of
channels for transmitting states between them. An essential requirement for the realization of
quantum networks is the control of light–matter interaction at the quantum level, in particular the
implementation of quantum memories enabling the reversible exchange of quantum information
between photons and atoms. In recent years, atomic ensembles have emerged as a promising
candidate to realize this goal. Photons can be easily absorbed in ensembles; moreover the atomic
systems can be engineered such that the light is reemitted in a well defined spatio-temporal mode
after the storage, thanks to a collective interference between the atoms. In this talk, I will describe
the experimental realization of the first enabling steps towards the implementation of quantum
networks using ensemble quantum memories, based on the one hand on cold atomic gases and
on the other hand on solid state systems.
The first part of the talk will be devoted to experiments with cold atomic ensembles where single
collective spin excitations are created by spontaneous Raman scattering and efficiently converted
to single photons by collective interference [2]. In particular, I will describe experiments
demonstrating entanglement between remote ensembles [3] and elementary segments of quantum
repeaters [4]. In the second part of the talk, I will focus on quantum memories for single photons in
a solid state environment. Some solid state systems have properties that make them very
attractive for quantum storage applications. In particular, rare-earth ion doped solids provide a
unique system where a large number of atoms with excellent coherence properties are naturally
trapped in a solid state matrix. I will describe the physical systems and explain how single photons
can be stored and retrieved using modified photon echo techniques. Finally, I will present the first
experimental steps towards solid-state quantum storage, including the realization of a solid-state
light matter interface at the single photon level [5].
[1] H.J. Kimble, Nature 453, 1023 (2008)
[2] L.M. Duan, M.D. Lukin, J.I Cirac and P. Zoller, Nature 414,413 (2001)
[3] C.W. Chou, H. de Riedmatten, ... and H.J. Kimble, Nature 438, 828 (2005)
[4] C.W. Chou, H. de Riedmatten, ... and H.J. Kimble, Science 316, 1316 (2007)
[5] H. de Riedmatten, M.Afzelius, M.U. Staudt, C.Simon and N.Gisin, Nature 456, 773 (2008)

Eine Zusammenfassung findet sich unter: http://www.ati.ac.at/fileadmin/files/general/Vortraege/BerufungsvortragAngewQuantenphysik_Riedematten.pdf


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Topic revision: r1 - 16 Jun 2009, waliddPHYSIKFHTUFAT

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