TeNPy Forum

Hello. Recently, I have calculated the four-point correlation function \braket{C^\dagger_{\downarrow,i} C^\dagger_{\uparrow,i+1} C_{\downarrow,j+1} C_{\uparrow,j}} by using the expectation_value_term(). def correlation(psi,a,b,c,d): L = psi.L f = np.zeros((L-1,L-1),dtype=complex) for i in range(L-1)...