2004/11/15 by Hanno Gassmann, Christoph Bruder, C. Bruder
Computer Science · Physics and Astronomy · #Action (physics) #Coupling (piping) #Dissipative system #Flow (mathematics) #Materials science #Mechanics #Nonlinear system #Physics #Quantum Information and Cryptography #Quantum and electron transport phenomena #Quantum mechanics #Renormalization #Renormalization group #Spin (aerodynamics) #Statistical physics #Theoretical and Computational Physics #Thermodynamics #cond-mat.other
paper · pdf · doi:10.1103/physrevb.72.035102
published as Phys. Rev. B 72, 035102 (2005). · 15 pages, 7 figures
arxiv created 2004/11/15 · openalex publication_date 2005/07/01 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We use the numerical flow-equation renormalization method to study a nonlinear bath at low temperatures. The model of our nonlinear bath consists of a single two-level system coupled to a linear oscillator bath. The effects of this nonlinear bath are analyzed by coupling it to a spin, whose relaxational dynamics under the action of the bath is studied by calculating spin-spin correlation functions. As a first result, we derive flow equations for a general four-level system coupled to an oscillator bath, valid at low temperatures. We then treat the two-level system coupled to our nonlinear bath as a special case of the dissipative four-level system. We compare the effects of the nonlinear bath with those obtained using an effective linear bath, and study the differences between the two cases at low temperatures.