Dear all, Since I used NEGF in my previous study, I want to use Green's function in Kwant. I have tried a simple Kwant program to check my understanding of "kwant.greens_function" and "lead.selfenergy(energy)", but it gives wrong results. I used Fisher-Lee relation to calculate the conductance: G = kwant.greens_function(sys, energy) Gr=G.submatrix(1,0) # r indicates retarded Ga=conj((Gr).T) # a indicates advanced Sigma_Lr =flead0.selfenergy(energy) #r indicates retarded Sigma_La =conj((Sigma_Lr).T) #a indicates advanced Sigma_Rr =flead1.selfenergy(energy) Sigma_Ra =conj((Sigma_Rr).T) Gamma_in =1j*(Sigma_Lr-Sigma_La) Gamma_out=1j*(Sigma_Rr-Sigma_Ra) #TM=Gamma_out*Gr*Gamma_in*Ga TM=Np.dot(Np.dot(Np.dot(Gamma_out,Gr),Gamma_in),Ga) #Fisher-Lee relation data.append(real(Np.trace(TM))) #Fisher-Lee relation Do I do I misunderstand anything? Can you please find my mistakes? My Kwant program code is attached at the end of this email. Thanks in advance! Best wishes, Weiyuan Tong