Tools for solving multiorbital impurity problems with frequency dependent hybridization function (matrix) using the numerical renormalization group were developed. The implementation was used as an impurity solver for self-consistent calculations on clusters (within the cluster dynamical mean-field theory). The range of applicability of the method on modern computers was established, and the expected errors estimated. The advantage of the method is the high energy resolution in the calculations of dynamical quantities (spectral functions and susceptibilities). We confirmed the existence of fine structure inside the energy bands of the Kondo lattice model in the antiferromagnetic phase.
D.09 Tutoring for postgraduate students
COBISS.SI-ID: 3038308dr. Kogoj has shown that the time-resolved pump-probe experiments are capable of distinguishing between regular bosonic degrees of freedom, e.g., phonons, and the hard-core bosons, e.g., magnons. The ability of phonon degrees of freedom to absorb essentially an unlimited amount of energy renders relaxation dynamics nearly independent of the absorbed energy or fluence. In contrast, the hard core effects pose limits on the density of energy stored in the bosonic subsystems resulting in a substantial dependence of the relaxation time on the fluence and/or excitation energy.
D.09 Tutoring for postgraduate students
COBISS.SI-ID: 2970212we presented some results of the analysis of empirical data and simulations of stochastic processes with content-based communication between agents on two types of web portals. We have shown how the emotional or cognitive contents affect the self-organized character of the process by simultaneously embodying the growing bipartite network along which this process takes place.
B.04 Guest lecture
COBISS.SI-ID: 29286439We presented the primary relaxation process of a photo excited charge carrier coupled to quantum Einstein phonons. If the pump pulse is sufficiently strong, the system relaxes after the primary energy redistribution towards a steady state. Then, the one-particle density matrix relevant for charge degrees of freedom along with the optical conductivity take up the form of their thermal counterparts. Our results indicate that steady states are (quasi)thermal and the temperature can be read out from the optical conductivity. Therefore, secondary relaxation processes observed in time resolved ultrafast spectroscopy can be efficiently described by applying (quasi)thermal approaches, e.g., the many-temperature models.
B.04 Guest lecture
COBISS.SI-ID: 3053412