Flow equations for dissipative quantum systems under non-equilibrium conditions
نویسنده
چکیده
Flow equations for dissipative quantum systems under non-equilibrium conditions This work investigates dissipative quantum systems by means of flow equations for Hamiltonians. We consider the time evolution of two models out of non-equilibrium initial states. As a first application the dis-sipative harmonic oscillator will be solved exactly. The insights gained will be used in the second and nontrivial model, the spin-boson model. A set of coupled differential equations will be derived that describes the time-evolution of the spin operators within approximations. Numerical implementations of these coupled differential equations are used to compare them with results from the non-interacting blip approximation (NIBA) and to calculate correlation functions in non-equilibrium. The thesis closes with a comparative discussion of the treated models and the closely related Kondo model.
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