toolbox/makescr

Introduction

The makescr code is often used to calculate the $K(\tau)$ from classic models or from the screening spectral function $W(\omega)$ (scr.frq.dat file). The results are necessary input for the NARCISSUS code.

Retarded interaction function/screening function $K(\tau)$:

\[K(\tau) = \int^{\infty}_0 \frac{d\omega}{\pi} \frac{\Im W(\omega)}{\omega^2} [\mathcal{B}(\omega,\tau)-\mathcal{B}(\omega,0)]\]

Shifted interaction $U_{\text{scr}}$:

\[U_{\text{scr}} = U + 2 \int^{\infty}_0 \frac{d\omega}{\pi}\frac{\Im W(\omega)}{\omega}\]

Shifted chemical potential $\mu_{\text{scr}}$:

\[\mu_{\text{scr}} = \mu + \int^{\infty}_0 \frac{d\omega}{\pi}\frac{\Im W(\omega)}{\omega}\]

Usage

$ ./mscr

Input

• See the terminal prompt
• scr.frq.dat (optional)

Output

• scr.tau.dat

Comment

In this code and NARCISSUS code, we assume that $K(\tau)$ is degenerated for multi-orbital system.

The $W(\omega)$ data are often obtained by the cRPA calculations. This feature is unfortunately not included in the iQIST software package.

In order to be compatible with the NARCISSUS code, you have to rename the output file (i.e., scr.tau.dat) to solver.ktau.in.

See also solver.ktau.in for more details.