Numerical Renormalization Group for Bosonic Systems and Application to the Subohmic Spin-Boson Model

Preprint

28 October 2003

preprint
Published by arXiv in arXiv

https://doi.org/10.48550/arXiv.cond-mat/0306708

Abstract

We describe the generalization of Wilson's Numerical Renormalization Group method to quantum impurity models with a bosonic bath, providing a general non-perturbative approach to bosonic impurity models which can access exponentially small energies and temperatures. As an application, we consider the spin-boson model, describing a two-level system coupled to a bosonic bath with power-law spectral density, J(omega) ~ omega^s. We find clear evidence for a line of continuous quantum phase transitions for subohmic bath exponents 0<s<1; the line terminates in the well-known Kosterlitz-Thouless transition at s=1. Contact is made with results from perturbative renormalization group, and various other applications are outlined.

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All Related Versions

Version 1, 2003-06-27, ArXiv
Version 2, 2003-10-28, ArXiv
Published version: Physical Review Letters, 91 (17), 170601.

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