def __init__(self, model_param):
# 0) read out/set default parameters
L = get_parameter(model_param, 'L', 2, self.__class__)
J = get_parameter(model_param, 'J', 1., self.__class__)
V = get_parameter(model_param, 'V', 1., self.__class__)
mu = get_parameter(model_param, 'mu', 0., self.__class__)
bc_MPS = get_parameter(model_param, 'bc_MPS', 'finite', self.__class__)
conserve = get_parameter(model_param, 'conserve', 'N', self.__class__)
unused_parameters(model_param, self.__class__)
# 1) - 3)
site = FermionSite(conserve=conserve)
# 4) lattice
bc = 'periodic' if bc_MPS == 'infinite' else 'open'
lat = Chain(L, site, bc=bc, bc_MPS=bc_MPS)
# 5) initialize CouplingModel
CouplingModel.__init__(self, lat)
# 6) add terms of the Hamiltonian
# (u is always 0 as we have only one site in the unit cell)
self.add_onsite(-np.asarray(mu), 0, 'N')
J = np.asarray(J) # convert to array: allow `array_like` J
self.add_coupling(-J, 0, 'Cd', 0, 'C', 1, 'JW', True) # (for a nearest neighbor model, we
self.add_coupling(-J, 0, 'Cd', 0, 'C', -1, 'JW', True) # could leave the `JW` away)
self.add_coupling(V, 0, 'N', 0, 'N', 1)
# 7) initialize MPO
MPOModel.__init__(self, lat, self.calc_H_MPO())
# 8) initialize bonds (the order of 7/8 doesn't matter)
NearestNeighborModel.__init__(self, lat, self.calc_H_bond())
def init_sites(self, model_params):
conserve = model_params.get('conserve', self.defaults['conserve'])
filling = model_params.get(
'filling',
(model_params.get('fill_top', self.defaults['fill_top']),
model_params.get('fill_bot', self.defaults['fill_bot'])))
filling = float(filling[0]) / filling[1]
print('init sites check ', filling)
site = FermionSite(conserve=conserve, filling=filling)
return site
def init_sites(self, model_params):
conserve = get_parameter(model_params, 'conserve', 'N', self.name)
site = FermionSite(conserve=conserve)
return site
def init_sites(self, model_params):
conserve = model_params.get('conserve', 'N')
fs = FermionSite(conserve=conserve)
gs = GroupedSite([fs, fs], labels=['A', 'B'], charges='same')
gs.add_op('Ntot', gs.NA + gs.NB, False)
return gs
def init_sites(self, model_params):
conserve = get_parameter(model_params, 'conserve', 'N', self.name)
filling = get_parameter(model_params, 'filling', 1 / 2., self.name)
site = FermionSite(conserve=conserve, filling=filling)
return site
def init_sites(self, model_params):
conserve = model_params.get('conserve', 'N')
site = FermionSite(conserve=conserve)
return site
def init_sites(self, model_params):
conserve = model_params.get('conserve', 'N')
filling = model_params.get('filling', (1, 8))
filling = filling[0] / filling[1]
site = FermionSite(conserve=conserve, filling=filling)
return site