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On the spin--boson model with a sub--Ohmic bath

Stefan Kehrein·Andreas Mielke
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Abstract

We study the spin--boson model with a sub--Ohmic bath using infinitesimal unitary transformations. Contrary to some results reported in the literature we find a zero temperature transition from an untrapped state for small coupling to a trapped state for strong coupling. We obtain an explicit expression for the renormalized level spacing as a function of the bare papameters of the system. Furthermore we show that typical dynamical equilibrium correlation functions exhibit an algebaric decay at zero temperature.

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Stefan Kehrein, Andreas Mielke. 1996-02-05. On the spin--boson model with a sub--Ohmic bath. https://doi.org/10.1016/0375-9601(96)00475-6

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