Regensburg 2016 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 64: Correlated Electrons: Nonequilibrium Quantum Many-Body Systems 1

TT 64.11: Vortrag

Donnerstag, 10. März 2016, 12:15–12:30, H22

Real-time dynamics after a parameter quench in the two-dimensional Kondo-lattice model with classical spins — •Lena-Marie Gebauer, Mohammad Sayad, and Michael Potthoff — I. Institut für Theoretische Physik, Universität Hamburg

The two-dimensional ferromagnetic Kondo lattice with localized spins coupled to a system of non-interacting conduction electrons is the prototypical model for layered manganites and can be simulated using ultracold fermions trapped in optical lattices. Here, we present a quantum-classical hybrid theory for the thermodynamics and the real-time dynamics of the model where the spins are treated as classical degrees of freedom. The relaxation of a single localized spin, the associated energy and spin dissipation and retardation effects are studied for a one-dimensional Kondo-impurity system [1]. For the lattice variant of the model in two dimensions, the equilibrium phase diagram is derived and found to agree well with previous classical Monte-Carlo data [2]. It comprises different phases, an antiferromagnet at half-filling as well as ferromagnetic, incommensurate and phase-separated states. We study the exact real-time dynamics initiated by quenches of the exchange coupling constant across different phase boundaries.

[1] M. Sayad, M. Potthoff, NJP (in press), arXiv:1507.08227
S. Yunoki et al., PRL 80, 845 (1998)