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

1996/02/05 by Stefan Kehrein, Andreas Mielke · 2 citations
Computer Science · Physics and Astronomy · #Cold Atom Physics and Bose-Einstein Condensates #Quantum Information and Cryptography #Quantum many-body systems #cond-mat

paper · pdf · doi:10.1016/0375-9601(96)00475-6

9 pages, 2 Postscript figures

arxiv created 1996/02/05 · openalex publication_date 1996/08/01 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

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.

Citations

• The renormalization group: Critical phenomena and the Kondo problem
• Dynamics of the dissipative two-state system
• Flow‐equations for Hamiltonians

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