Response function

One simple way to represent a spectrum, for example one that is calculated using the function CreateSpectra(), is a sum over the poles multiplied by the residues: $$I(\omega) = \sum_{k} \frac{R_k}{\omega - \omega_k + i \gamma/2}$$ A more compact way to store this spectrum is by just using two arrays for the values of $\{R_k\}$ (residues) and $\{\omega_k\}$ (poles). This is precicely the purpose of the object type Response Function.

text produced as output