High-Frequency moments of the Green’s function

The coefficients of the high-frequency expansion of a Green function (in short tail) play an essential role in acquiring accurate results for e.g. Fourier transforms and density calculations.

\[G(i\omega) \approx \sum_{n = 0}^N \frac{a_n}{(i\omega)^n}\]

The TRIQS library provides functionalities to determine these tail coefficiencts through a least-square fitting procedure.

Python API

In Python, the fit_tail functions are not free but are rather member functions of the respective Green functions.


The functionality is otherwise identical to C++.