Berlin 2024 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 16: Nonequilibrium Quantum Systems 1 (joint session TT/DY)
DY 16.10: Vortrag
Dienstag, 19. März 2024, 12:00–12:15, H 3005
Mean-field Decoupling of Single Impurity Anderson Model through Auxiliary Majorana Fermions — •Irakli Titvinidze1, Julian Stobbe1, Alexey N. Rubtsov2, and Georg Rohringer1 — 1I. Institute of Theoretical Physics, University of Hamburg, 20355 Hamburg, Germany — 2Moscow
We present a new method to study the time evolution of the single impurity Anderson model. We perform a mean-field decoupling of the impurity and the chain. This is achieved by introducing a pair of auxiliary Majorana fermions between the impurity and the chain. We obtain a self-consistent set of equations for the impurity and the chain. By solving them in equilibrium we obtain a phase transition between phases in which the mean field parameters are zero and we have a well-defined spin on the impurity, and the regime in which the mean field parameters take finite values and there is no well-defined spin. Once we know the equilibrium properties of the system, we quench one or more model parameters and study the time evolution of the impurity and the chain. Within our mean-field treatment, we obtain a coupled set of differential equations for the impurity and chain and find that the results converge to their equilibrium values for most quenches. For very strong interactions, the excitations are trapped and the oscillations never persist.
Keywords: Quantum Impurity; Kondo Physics; Time evolution; Mean-field