Regensburg 2010 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 19: Quantum Chaos
DY 19.1: Topical Talk
Mittwoch, 24. März 2010, 14:00–14:30, H38
Chaotic Scattering in Microwave Billiards With and Without Time-Reversal Invariance — •Barbara Dietz1, Thomas Friedrich2, Hanns L. Harney3, Maksim Miski-Oglu1, Achim Richter1,4, Florian Schäfer1,5, and Hans A. Weidenmüller3 — 1TU Darmstadt, D-64289 Darmstadt — 2GSI Helmholtzzentrum für Schwerionenphysik GmbH, D-64291 Darmstadt — 3MPI für Kernphysik, D-69029 Heidelberg — 4ECT*, Villa Tombosi, I-38100 Villazzano — 5LENS, University of Florence, I-50019 Sesto-Fiorentino
We discuss measurements of scattering amplitudes of a chaotic microwave resonator in the regime of isolated and overlapping resonances. Below a certain excitation frequency the resonator simulates a quantum billiard, whose eigenvalues manifest themselves in the spectra as resonances with average spacing d and width Γ. Violation of time-reversal (T) invariance is achieved with a magnetized ferrite inside the cavity. The experimental observables are complex scattering (S)-matrix elements, measured for the resonator with and without T invariance as a function of frequency. Particular emphasis is given to S-matrix correlation functions in the regime of weakly overlapping resonances, i.e. Γ /d≃ 1, and their comparison to results from the theory of chaotic scattering developed in nuclear reaction theory. We also present results on the distribution of the S-matrix elements and higher order correlation functions. Here, a focus is the transition from the regime of weakly overlapping resonances to the Ericson regime, i.e. from non exponential to exponential decay of the system of resonances. This work was supported by the DFG within the SFB634