Abstract Two-dimensional scattering systems with mixed phase space can often be represented by low order Smale horseshoes with a low degree of development. For such systems we show that incoming packets, both of classical points and quantum mechanical waves, display echoes, whose period is directly related to the degree of development of the horseshoe. Thus the period of reverberation of the cavity gives topological information about the classical trajectories, even far from the semiclassical regime. This is possible because we do not have to measure noncommuting observables. Recent experiments in superconducting cavities confirm these predictions and furthermore show that reverberations from deep inside the integrable island can be measured over hundreds of periods.
Seminarsko predavanje bo v petek 5. septembra ob 15:15 uri v seminarski sobi CAMTP na Krekovi 2, pritlicje desno. Vljudno vabljeni vsi zainteresirani, tudi študentje.