Takes two argument, the time-step size δt and the momentum-space real-time correlator file, expected to be of the form: More...

Detailed Description

Takes two argument, the time-step size δt and the momentum-space real-time correlator file, expected to be of the form:

t Re(0) Im(0) Re(1) Im(1) Re(2) Im(2) ....

lines starting with '#' are ignored. Optionally, you may pass in a third argument, which, when given, enables damping of the data to avoid spectral leakage.

The transformation is defined as

\( S(k,\omega) = \sum_{t=0}^T e^{-i\omega t} \mathrm{Re}\left\{ S(k,t) \right\} \)

The real part alleviates the fact that we only sum from \( t = 0 \) instead of \( t = -\infty \) by using space translational invariance, time translational invariance and symmetry under real-space parity.