ham = []
#set hubbard U operator
for isite in range(0, 4):
ham.append(fermion.DoubleOcc(Mf, U, isite, 'D'))
#set eR operator
for isite in range(4, 8):
for iflv in range(0, Mf):
ham.append(fermion.Number(Mf, eR, isite, iflv, 'R'))
#set kinetic energy operator
#nickel hopping
for isite in range(0, 4):
jsite = (isite + 1) % 4
for iflv in range(0, Mf):
ham.append(fermion.Hop(Mf, -t, isite, jsite, iflv, 'H'))
#R hopping
for isite_c in range(0, 4):
isite = 4 + isite_c
jsite = 4 + (isite_c + 1) % 4
for iflv in range(0, Mf):
ham.append(fermion.Hop(Mf, -tR, isite, jsite, iflv, 'H'))
#Ni-R hybridisation
for isite in range(0, 4):
jsite = isite + 4
for iflv in range(0, Mf):
ham.append(fermion.Hop(Mf, -tp, isite, jsite, iflv, 'H'))
#-------------set up hamiltonian matrix-----------------------------
ham = []
#set hubbard U operator
for isite in range(0, 2):
ham.append(fermion.DoubleOcc(Mf, U, isite, 'D'))
#set eR operator
for isite in range(2, 4):
for iflv in range(0, Mf):
ham.append(fermion.Number(Mf, eR, isite, iflv, 'R'))
#set kinetic energy operator
thop_ar = [t, tp, tR, tp]
for isite in range(0, 4):
jsite = (isite + 1) % 4
for iflv in range(0, Mf):
ham.append(fermion.Hop(Mf, -thop_ar[isite], isite, jsite, iflv, 'H'))
#-------------set up hamiltonian matrix-----------------------------
hmat = np.zeros((n_dim_fs, n_dim_fs), np.cdouble)
for fsoper in ham:
for isnum in fockspace:
ifsstate = copy.deepcopy(fockspace[isnum])
i = mat_idx[isnum]
factor = fsoper.act_on(ifsstate)
if not ifsstate.isZero:
jsnum = ifsstate.fock_state_number()
j = mat_idx[jsnum]
mat_elem = factor * fsoper.coeff
hmat[j, i] += mat_elem