Dear Sir / Ma'am,

I was calculating the ground state enrgy for extended hubbard model using the code provided in sample folder. I used the range for U1 to be -8 to 8, and the range for V1 (nearest neighbour spin-spin interaction) to be in the range -6 to 6. in the above range, for some region of negative V1, the energy was not converging. It will be very helpful if someone can tell me what is going wrong here.

Some other points about the parameters I used:

I used a lattice site of 10, with half-filling

I used periodic boundary condition

The sweeps were following:

nsweeps = 60

sweeps

{

maxdim mindim cutoff niter noise

50 10 1E-12 2 1E-7

100 20 1E-12 2 1E-8

200 20 1E-12 2 1E-10

400 20 1E-12 2 0

800 20 1E-12 2 1E-11

800 20 1E-12 2 0

}

Best,

Sreetama