Quantum dynamics and decoherence in generalized Coleman-Hepp model and boson detector model S. Kitajima, C. Takahashi and F. Shibata Eur. Phys. J. D, 30 3 (2004) 417-423 Published online: 10 August 2004 DOI: 10.1140/epjd/e2004-00092-4