Dresden 2014 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 12: Quantum Dynamics, Decoherence and Quantum Information (organized by DY)

TT 12.7: Talk

Monday, March 31, 2014, 11:30–11:45, HÜL 186

Optimal control of non-interacting (quantum) harmonic oscillators and qubits — •Frank Boldt and Karl Heinz Hoffmann — Professur Theoretische Physik, insbesondere Computerphysik, Technische Universität Chemnitz

In this talk the time-optimal and decoherence free control of an ensemble of non-interacting (quantum) harmonic oscillators is given, using an geometrical approach based on the Casimir companion [1]. These time-optimal decoherence free passages are shortcuts to adiabaticity. Therefore fast optimal cooling processes are possible and maximum cooling rates will be given [2]. Further, time-optimal and decoherence free controls of an ensemble of non-interacting qubits will be deduced as a second example [3].
The optimal controls presented are piece-wise continuous functions (Bang-Bang controls) and thus hard to realize experimentally. As an outline, bounds for continuous controls with finite switching times were calculated to give experimenters hard limits for instance to adjust their experimental realized version of the control by a feedback loop.
[1] F. Boldt et al., PRA 87, 022116 (2013)
[2] P. Salamon et al., Phys. Chem. Chem. Phys., 2009, 11, 1027-1032
[3] F. Boldt et al., EPL 99, 40002 (2012)