Abstract: We discuss quantum fidelity decay of classically regular dynamics, in particular for an important special case of a vanishing time averaged perturbation operator. A complete semiclassical picture of this situation is derived in which we show that the quantum fidelity of individual coherent initial states exhibits three different regimes in time: (i) first it follows the corresponding classical fidelity up to time , (ii) then it freezes on a plateau of constant value, (iii) and after a time scale it exhibits fast ballistic decay as where is a strength of perturbation. A similar picture is worked out also for general initial states, and specifically for random initial states, where , and . This prolonged stability of quantum dynamics in the case of a vanishing time averaged perturbation could prove to be useful in designing quantum devices.
Seminarsko predavanje bo v petek, 5. septembra 2003 ob 17:15 uri v seminarski sobi CAMTP na Krekovi 2, pritlicje desno. Vljudno vabljeni vsi zainteresirani, tudi študentje.