solver.umat.in

Introduction

The solver.umat.in file contains the density-density part of the general Coulomb interaction matrix. Some CT-HYB quantum impurity solvers can read it. It is compatible with the AZALEA, GARDENIA, NARCISSUS components. These components may utilize it to redefine the internal (default) Coulomb interaction matrix.

Format

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

column 1: orbital index $i$, integer

column 2: orbital index $j$, integer

column 3: Coulomb interaction matrix element $U(i,j)$, double precision

Note

In the solver.umat.in file, we adopt the following orbital sequence: $1\uparrow$, $2\uparrow$, $3\uparrow$, $\cdots$, $1\downarrow$, $2\downarrow$, $3\downarrow$, $\cdots$ In other words, the spin up part is always before the spin down part.

Code

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

! open file atom.umat.dat to write
     open(mytmp, file='solver.umat.in', form='formatted', status='unknown')

! write the data, all of the elements are outputed
! note: we have to change the spin sequence here
     do i=1,norbs
         if ( i <= nband ) then
             k = 2*i-1
         else
             k = 2*(i-nband)
         endif ! back if ( i <= nband ) block

         do j=1,norbs
             if ( j <= nband ) then
                 l = 2*j-1
             else
                 l = 2*(j-nband)
             endif ! back if ( j <= nband ) block

             write(mytmp,'(2i6,f16.8)') i, j, umat_t(k,l)
         enddo ! over j={1,norbs} loop
     enddo ! over i={1,norbs} loop

! close data file
     close(mytmp)

See also solver.umat.in for more details.