National Repository of Grey Literature 2 records found  Search took 0.00 seconds. 
Study of time evolution of metastable states in quantum mechanics
Gedeonová, Hedvika ; Kolorenč, Přemysl (advisor) ; Čížek, Martin (referee)
In this thesis, the metastable states are studied. The work focuses on a theoretical model of one or two metastable states decaying into a continuum of states which is bounded from below. We examine the time evolution of such systems and how it is affected by the energy of the metastable state(s) and by the position of the poles of the scattering matrix in the complex plane. We also look closely at the spectral line shape. Numerical integration of a system of differential equations is used for solving the problem of the time evolution and spectral line shape while Freshbach-Fano projection operator formalism is used for finding the position of the poles. The results are compared with first order perturbation theory and with semi-analytical formula obtained from adiabatic elimination of the continuum. The last part of the thesis is dedicated to an application of the model on neon-helium-neon cluster. 1
Time-Dependent Solution of the Generalized Fano Model
Gedeonová, Hedvika ; Kolorenč, Přemysl (advisor) ; Horáček, Jiří (referee)
In this thesis, the time evolution of Fano model, describing a discrete state embedded in a continuum of states with constant coupling, and generalized ver- sion of Fano model for an energy dependent coupling are investigated. For the time evolution of the generalized system, numerical simulation (Gaussian quadra- ture and numerical integration of a system of differential equations) is used. The system behaves as Fano model predicts when energy-dependent coupling tends to a constant one, and the system exponentially decays into the continuum. For a strongly energy-dependent coupling, the system oscillates between the initial discrete state and the continuum. The thesis provides numerically evaluated time evolution for different parameters of the coupling, brief interpretation of proba- bility oscillation phenomenon and study of the transition between oscillatory and non-oscillatory mode. 1

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2 Gedeonová, Hedviga
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