Hi Mohammad,
You are missing the imaginary unit in the definition. In any case, DMRG at the moment does not work with complex numbers. You would have to measure Splus and Sminus, and then combine the results. But all this only makes sense assuming that your Hamiltonian already mixes states with different Sz. What model are you studying?
Saludos, <ADRIAN>
zhian asadzadeh wrote:
Hi All,
I am using DMRG for my problem, I need to calculate expectation value of Y component of Spin operator (Sy) , As a result, I need to define it in the model.xml file. How I can define it? I tried with Sy(i)=1/(2*sqrt(-1))*(Splus(i)-Sminus(i)), but I got incorrect results. I will be very appreciate if someone could help me?
Thank you very much, Mohammad.