Inconsistent computation of susceptibility in analysis
The analysis program cov_tau.F90 computes time-displaced correlations by taking the trace over the orbital index.
do no = 1,Norb
bins(n,nt,nb-n_skip) = bins(n,nt,nb-n_skip) + &
& ( OneBin(nt,no,no) + OneBin(Lt - nt + 1,no,no) ) / cmplx(2.d0,0.d0,Kind(0.d0))
enddo
do no = 1,Norb
bins(n,nt,nb-n_skip) = bins(n,nt,nb-n_skip) + OneBin(nt,no,no)
enddo
However, the susceptibilities are computed by summing over all elements of the correlation matrix.
do no = 1,Norb
do no1 = 1,Norb
Z = Z + cmplx(0.5d0,0.d0,Kind(0.d0)) * ( OneBin(nt,no,no1) + Onebin(nt+1,no,no1) )
enddo
enddo
Such a behavior is inconsistent and in many cases probably unwanted.
The branch 126-analysis-order-parameter-for-multi-orbital-models solves the problem, in that it allows for a generic linear combination of the elements of the correlation matrix.