Controllable precision of the projective truncation approximation for Green’s functions
Fan Peng, Tong Ning-Hua †
       

(a) 〈 n ↑ 〉 and (b) 〈 n ↑ n ↓ 〉 as functions of δ ω . The parameters are U=2.0, T=0.1, ϵ d = − U / 2 .