Dresden 2006 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 29: Transport: Quantum Coherence and Quantum Information Systems - Part 1

TT 29.5: Vortrag

Donnerstag, 30. März 2006, 10:45–11:00, HSZ 304

Analytic solution for the multiphoton resonances in the mono- and bichromatically driven quantum Duffing oscillator — •Michael Thorwart and Vittorio Peano — Institut für Theoretische Physik IV, Universität Düsseldorf

We investigate the nonlinear response of an anharmonic monostable quantum mechanical resonator to external periodic mono- and bichromatic driving in presence of a harmonic bath. We therefore apply a Floquet-Born-Markovian master equation for the reduced density operator. The quasienergies of the pure system show multiple avoided level crossings corresponding to multiphoton transitions in the resonator. Around the resonances, the master equation can be solved analytically using Van-Vleck perturbation theory. Studying the oscillator position, the lineshape of the resonances will be calculated resulting in simple expressions. For the monochromatic case, we find the general solution for the multiple multiphoton resonances and, most interestingly, a bath-induced transition from a resonant to an antiresonant behavior. In the bichromatic case, the harmonic mixing signals are calculated. Our model finds applications in a suspended nanomechanical beam excited to transverse vibrations as well as for the inductive measurement of a superconducting qubit by a driven Josephson junction.