How to write coupled mode equation of a given structure

[TimelordZhou]

Recently I am reading the papers in the field of PT symmetry systems. What I am confused is that in these papers, authors directly write out the equations describe the dynamics of the given systems( For example, in this paper http://arxiv.org/ftp/arxiv/papers/1103/1103.3389.pdf , authors put forward a honeycomb photonic lattice and they just write out the equations).
Now I am reading the papers about CMT written by Haus and Huang, but I still can not figure out how to write the equation describe the dynamics of a given structure.
So my question is that what I need to do so that I can give the coupled mode equations.

Thanks.

 

[UltrafastPED]

You will have to follow the references; the equations will be derived there, or in further references.

For example, the origin of the system of equations (1) will be explained in references [3-5].

This "tight binding" model is an application of a "standard" model from condensed matter physics to their particular problem, and will originate in a standard textbook in one of the references [3-5].

Thus when you are reading a paper in a new field you may also have to read a number of the references. It is often easier to seek out a review paper so that the slogging has been simplified by an expert in the area.