Berlin 2015 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 45: Correlated Electrons: Nonequilibrium Quantum Many-Body Systems 3 (jointly with DY)

TT 45.8: Vortrag

Dienstag, 17. März 2015, 15:45–16:00, H 3010

Time evolution of the ohmic spin boson model at finite bias in the weak coupling limit — •Carsten Lindner and Herbert Schoeller — Institut für Theorie der Statistischen Physik, RWTH Aachen

The spin boson model is a prominent model which describes dissipation in a quantum mechanical two-state system caused by an energy exchange with the environment. Proposed for applications in various fields of condensed matter physics, it has been discussed widely for more than twenty years. However, a full systematic analysis of the weak coupling regime has not been done for a long time. Recently, the time evolution of the ohmic spin boson model at zero bias has been investigated in the case of weak coupling where the interaction with the environment can be regarded as a small perturbation [1]. Therefore, a non-equilibrium renormalization group (RG) method, which has come to be known as the real-time RG (RTRG), has been employed to determine its time evolution. The choosen approach allows to obtain the time evolution in a controlled way which means that the renormalized coupling parameters stay small for arbitrarily long times. Beside predicting the dominant exponential time evolution, this method also enables us to address the time scaling behavior of the pre-exponential functions precisely. Based on this insight, we have investigated the ohmic spin boson model at finite bias accordingly, leading to new results on all time scales.

[1] O. Kashuba and H. Schoeller, Phys. Rev. B 87, 201402(R) (2013)