Abstract
A continuous time cluster algorithm for two-level systems coupled to a dissipative bosonic bath is presented and applied to the sub-Ohmic spin-boson model. When the power of the spectral function is smaller than , the critical exponents are found to be classical, mean-field like. Potential sources for the discrepancy with recent renormalization group predictions are traced back to the effect of a dangerously irrelevant variable.
- Received 29 July 2008
DOI:https://doi.org/10.1103/PhysRevLett.102.030601
©2009 American Physical Society