Regensburg 2010 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 27: CE: Poster Session

TT 27.56: Poster

Wednesday, March 24, 2010, 14:00–18:00, Poster D1

Scaling approach to a time-dependent Kondo model: from adiabatic switching to an interaction quench — •Constantin Tomaras and Stefan Kehrein — LMU München, Department für Physik und Arnold-Sommerfeld-Center for Theoretical Physics, Theresienstraße 37, D-80333 München, Germany

The time-dependent quantum many-body problem has become of particular interest within the recent years [1]. Less is known about the transition from adiabatic turning on the interaction to an interaction quench in generic many-body systems. For the Hubbard model the quench physics were accessible with the help of flow equations [2], while the transition to an adiabatic switching procedure has been investigated by means of Keldysh perturbation theory [3]. Here we consider the isotropic ferromagnetic Kondo model, in which the interaction is switched on according to the time-dependent exchange couplings J_kk′(t). Following [4,5], a convenient measure of the deviation of the impurity-spin z-component, from idealized adiabatic evolution is the ratio µ=⟨0|S^z(t→∞)−S^z|0⟩/(⟨0|S^z|0⟩−⟨0|S^z|0⟩). |0⟩,|0⟩ are the ground states of the interacting and non-interacting system. Applying some generalized renormalization scheme, the ratio µ is shown to interpolate continuously between its quenched and adiabatic value.

[1] M. Greiner et al. Nature, 419 (2002)

[2] M. Moeckel and S. Kehrein, PRL, 100 (2008)

[3] M. Moeckel and S. Kehrein, arXiv.org:0911.0875 (2009)

[4] A. Hackl, S. Kehrein, M. Vojta, arXiv.org:0908.3647 (2009) [5] A. Hackl et al. PRL, 102 (2009)