Hello everybody... I have questions about how to implement the metropolis algorithm to the Kosterlitz-Thouless model. Many questions!! When I create a LxL lattice I give an angle for every spin vector in every position (i,j) of the lattice or the projection of the vector? The Hamiltonian of the model is Η=-JΣi,jCos(theta_i-theta_j) And then how energy is defined?? And the weight factor of the metropolis alogrithm?? Pleeeeease help... I need this by tommorow!!