Hi  All,<br><br>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?<br>
<br>Thank you very much,<br>Mohammad.<br><br>