Düsseldorf 2007 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 47: Quanteninformation (Quantenkommunikation)
Q 47.1: Talk
Wednesday, March 21, 2007, 16:30–16:45, 5L
Towards the Solution of NP Problem: Indistinguished controllable single photons from independent atomic ensembles — •Yu-Ao Chen1, Shuai Chen1, Markus Koch1, Thorsten Straßel1, Zhen-Sheng Yuan1, Jörg Schmiedmayer2, and Jian-Wei Pan1 — 1Physikalisches Institut, Universität Heidelberg, Philosophenweg 12, D-69120 Heidelberg, Germany — 2Atominstitut der Österreichischen Universitäten, TU-Wien, A-1020 Vienna, Austria
Quantum repeater hold the promise for revolutionary advances to solve the NP problem from the losses and decoherence in the communication channel by a distribution of quantum resources over remote locations and quantum memory.
We use collective spin excitation of atoms as a media for quantum memory. Here we present an implementation of feed forward control of two atomic memories. We use independent "write" laser sources to map the quantum states to the collective spin excitation and again we use independent "read" lasers to retrieve the quantum states from the two atomic memories respectively. We will show that, by using a feed forward circuit, the probability of simultaneously obtaining a pair of single photons will be increased by orders of magnitude. As an application, we show the indistinguishability of independently generated single photons by the observation of destructive interference of their wave packets. Our results demonstrate experimentally a basic principle for enabling scalable quantum communication networks and linear optical quantum computation.