Non-Markovian decoherence of a two-level system weakly coupled to a bosonic bath A. A. Slutskin, K. N. Bratus', A. Bergvall and V. S. Shumeiko EPL, 96 4 (2011) 40003 Published online: 02 November 2011 DOI: 10.1209/0295-5075/96/40003