Mainz 2017 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 31: Poster: Quantum Optics and Photonics I

Q 31.47: Poster

Dienstag, 7. März 2017, 17:00–19:00, P OG1+2

Experimental analysis of decoherence mechanisms in a single-atom memory for photonic qubits — •Stefan Langenfeld, Matthias Körber, Olivier Morin, Andreas Neuzner, Stephan Ritter, and Gerhard Rempe — Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Strasse 1, 85748 Garching, Germany

Quantum memories can preserve qubits for an extended duration. In combination with the capability to map photonic qubits into and out of the memory, this has important applications in quantum computation and communication. To improve on achievable coherence times, a thorough understanding of the relevant decoherence mechanisms is indispensable. Our system consists of a single atom trapped in a two-dimensional optical lattice in a high-finesse cavity [1]. The qubit is initially stored in a superposition of Zeeman states, making magnetic field fluctuations the dominant decoherence mechanism. We reduce the magnetic field induced decoherence by transferring the qubit into a decoherence-free subspace. Here, the coherence time is no longer limited by magnetic field noise, but by differential light shifts of the new qubit states. We will discuss how this new limitation can be overcome and which future steps can be taken to further increase the coherence time.

[1] H. Specht et al., Nature 473, 190 (2011).