Equilibrium dynamics of the sub-Ohmic spin-boson model under bias
Zheng Da-Chuan, Tong Ning-Hua
       

(color online) (a)–(c): C(ω) for the same α values. For each α, from top to bottom, ε = 0, 10−7, 10−6, 10−5, 10−4, and 10−3. NRG parameters are the same as Fig. 4.