Indeed, the input is wrong, it should be:

CONSERVED_QUANTUMNUMBERS="N"; N_total=4;

On Aug 19, 2009, at 2:36 PM, Bob Gooding wrote:

If I use

mu = -W*(rand()-1/2)

then this is equivalent in to the Anderson Hubbard model with random on-site energies - a box distribution of strength W. (That is, the grand Hamiltonian

H - mu*N

becomes the Anderson Hubbard Hamiltonian (H only).)

We are completing our work in the fixed particle number canonical ensemble, and my understanding of the conserved quantum numbers option is that if I specify N_total=4 (say) then the calculation is completed in the canonical ensemble.

So, perhaps my error (???) is in the use of

CONSERVED_QUANTUMNUMBERS="N_total"; N_total=4;

...

Could it be just that the values of mu are such that the ground state has no particles? Matthias