Heidelberg 2015 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 3: Quantum Information: Concepts and Methods I

Q 3.3: Vortrag

Montag, 23. März 2015, 12:15–12:30, K/HS1

Universal composite pulses for robust rephasing of atomic coherences in a doped solid — •Daniel Schraft, Genko Genov, Thomas Halfmann, and Nikolay Vitanov — Institute of Applied Physics, Technical University of Darmstadt, Germany

Composite pulses (CP) have been used for decades in NMR, and since recently, also in quantum information processing as a powerful tool to drive excitation processes via robust pathways. Usually these CP compensate fluctuations in a single experimental parameter only. Here we introduce universal CP [1] for robust system inversion, compensating variations in any experimental parameter (i.e. pulse area, static detuning, etc.), which also operate independent of the pulse shape.

We demonstrate the robust performance of universal CP by inversion of atomic coherences in a rare earth ion-doped solid (Pr:YSO). Such doped solids are an attractive medium to implement solid-state quantum memories. The media exhibit long decoherence times and small homogenous optical line width, while maintaining the advantages of solids, i.e. large density and scalability. These memories rely on atomic coherences, driven in a inhomogeneously broadened medium. Hence, robust rephasing protocols are required to cope with dephasing. Our experimental data confirm improved robustness of universal CP compared to rephasing by standard π-pulses, with regard to variations in pulse area, static detuning, additional chirps, and different pulse shapes.

[1] G. T. Genov, D. Schraft, T. Halfmann, and N. V. Vitanov, Phys. Rev. Lett. 113, 043001 (2014).