Dear friends, Can any body guide me how to make the program in FORTRAN77/90 or in C on square lattice for the
following quantum spin (anti-ferromagnetic) model:
H = J*nnsum(i,j)*S_{i}*S_{j} +
J'*sum(i)*sum(delx)*sum(dely)*[(S_{i}*S_{i+delx})*(S_{i+delx+dely}*S_{i+2*delx+dely})]
First term is simply Heisenberg term and second is another type coupling term. Thanking you,
With Best regards Rakesh Kumar School of Physical Sciences, JNU, New Delhi-110067 (INDIA) Mob.No.: +91-9891397108
--------------------------------- Yahoo! Messenger with Voice. Make PC-to-Phone Calls to the US (and 30+ countries) for 2¢/min or less.