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solver.anydos.in

Introduction

In the CT-QMC impurity solvers contained in the iQIST software package, we provide a mini dynamical mean-field theory engine. This engine implements a self-consistent condition for the Bethe lattice which has a semi-circular density of states with bandwith $4t$. Sometimes you may want to try the other models with arbitrary density of states.

Is it possible?

Yes, of course. You can define your density of states in the solver.anydos.in file. And then you have to hack the ctqmc_dmft.f90 file.

Change the following codes

......
     use context, only : grnf
......
! calculate new hybridization function using self-consistent condition
     call ctqmc_dmft_bethe(hybf, grnf)

to

......
     use context, only : grnf, sig2
......
! calculate new hybridization function using self-consistent condition
     call ctqmc_dmft_anydos(hybf, grnf, sig2)

You have to be very careful. Finally, recompiling the CT-QMC impurity solvers is necessary.

Note
  1. Don't forget to set the isscf parameter to 2, or else the CT-QMC impurity solvers will skip the dynamical mean-field theory engine and perform one-shot calculation only.
  2. The HF-QMC impurity solver (the DAISY component) does not support this file/feature.

Format

The format of the solver.anydos.in file is as follows:

column 1: frequency point, $\epsilon$, double precision

column 2: density of states, $\rho(\epsilon)$, double precision

Note

We assume that:

  1. The orbitals are degenerated.
  2. The number of frequency points is 801.

If you are not satisfied with these assumptions, you have to hack the corresponding ctqmc_dmft.f90 by yourself.

Code

The corresponding Fortran code block for the reading of solver.anydos.in file is as follows:

open(mytmp, file='solver.anydos.in', form='formatted', status='unknown')
do i=1,ngrid
    read(mytmp,*) epsi(i), pdos(i,1)
    do j=2,norbs
        pdos(:,j) = pdos(:,1)
    enddo ! over j={2,norbs} loop
enddo ! over i={1,ngrid} loop
close(mytmp)

For some typical models, the solver.anydos.in file can be generated using the toolbox/makedos tool which is included in the HIBISCUS component. See toolbox/makedos for more details.