Hamburg 2009 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 63: Quanteninformation: Quantencomputer
Q 63.2: Talk
Friday, March 6, 2009, 14:15–14:30, VMP 6 HS-A
Quantum gates between atoms coupled by a nano-wire — •David Dzsotjan1,2 and Michael Fleischhauer1 — 1Fachbereich Physik, Technische Universität Kaiserslautern, Germany — 2Research Institute for Particle and Nuclear Physics, XII. Konkoly-Thege ut. 29-33, H1525, Budapest, PO Box 49, Hungary
We investigate the long-range coupling of single atoms placed close to the surface of a metallic, cylindrical nanowire. Putting the emitter close to the surface of the wire, a strong Purcell effect can be observed: with very high probability, the emitter will decay into guided modes of the wire, the so-called surface plasmons [1], [2], with a rate exceeding that of free space by a large factor. The strength of the coupling originates from the fact that surface plasmon modes have an extremely small mode volume, being confined at around the surface of the nanowire. We find furthermore that there is an optimal, sub-wavelength emitter-wire distance where the coupling to the plasmon modes is maximal due to the losses originating from circulating currents. When two emitters are placed along the wire, we observe a strong, wire-mediated long-range interaction. As a result of this, super- and subradiance can occur over distances large compared to the resonant wavelength. Using this effect, one can construct quantum gates and in duce entanglement among qubits along the wire. As a specific application, we propose a scheme for constructing a phase gate by a wire-mediated interaction of two lambda atoms.
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