Dear ALPS community,
I am using the DMRG programs (with OBC) to calculate the spin-spin
correlations of a spin chain.
Suppose N is the number of sites in the chain. My question is - while using
the DMRG programs, is it possible to restrict calculations of correlations
to a distance "d" between two sites where d<<N?
Eg. instead of calculating all the N**2 correlations between all the spins,
calculate only nearest neighbours or N-1 correlations?
I want to obtain correlations for N>128 sites. ~60GB of RAM on a
workstation is proving insufficient for this. I have been able to obtain
local spin components <S_i^a> (a=x,y,z) for N=512 too. But, for the
correlation calculations, N**2 correlations require more than 4 times the
available RAM even for N=128. So I have to use smaller N, which leads to
pronounced effects due to finite size and boundaries.
Hence, the question.
Thanks very much.
with regards,
Pradeep Thakur.