- Problem Statement
- Relevant Equations
I am not sure where does the dy term, phi^2 and phi^4 terms come from.
I guess there are dx and dy because we have to account for the nearest neighbour pairs in the x and y axis?
I guess there is a phi^2 term because 2q_a*q_b=(q_a-q_b)^2-q_a^2-q_b^2, the term q_a^2-q_b^2?
How about the phi^4 term?