def relabel_operators(op, from_list, to_list):
""" Transform the operator op according to the single particle
transform matrix U defined in the subspace of operators listed in
fundamental_operators. """
op_idx_map = get_operator_index_map(from_list, include_dag=True)
op_idx_set = set(op_idx_map)
from_list, to_list = list(from_list), list(to_list)
# -- Loop over given operator and substitute operators
# -- in from_list to to_list
op_trans = Operator()
for term in op:
op_factor = Operator(1.)
for factor in term:
if type(factor) is list:
for dag, idxs in factor:
tup = (dag, tuple(idxs))
if tup in op_idx_set:
op_factor *= to_list[op_idx_map.index(tup)]
else:
op_factor *= {False: c, True: c_dag}[dag](*idxs)
else: # constant prefactor
op_factor *= factor
op_trans += op_factor
return op_trans
def operator_single_particle_transform(op, U, fundamental_operators):
""" Transform the operator op according to the single particle
transform matrix U defined in the subspace of operators listed in
fundamental_operators. """
# -- Convert fundamental operators back and forth from index
op_idx_map = get_operator_index_map(fundamental_operators)
op_idx_set = set(op_idx_map)
# -- Transformed creation operator
def c_transf(s, i):
if (s, i) not in op_idx_set:
return c(s, i)
k = op_idx_map.index((s, i))
ret = Operator()
for l in range(U.shape[0]):
op_idx = op_idx_map[l]
ret += U[k, l] * c(*op_idx)
return ret
# -- Precompute transformed operators
op_trans_dict = {}
for fop in fundamental_operators:
dag, idxs = op_serialize_fundamental(fop)
op_trans_dict[(dag, idxs)] = c_transf(*idxs)
op_trans_dict[(not dag, idxs)] = dagger(c_transf(*idxs))
# -- Loop over given operator and substitute operators
# -- fundamental_operators with the transformed operators
op_trans = Operator()
for term in op:
op_factor = Operator(1.)
for factor in term:
if type(factor) is list:
for dag, idxs in factor:
tup = (dag, tuple(idxs))
if tup in list(op_trans_dict.keys()):
op_factor *= op_trans_dict[tup]
else:
op_factor *= {False: c, True: c_dag}[dag](*idxs)
else: # constant prefactor
op_factor *= factor
op_trans += op_factor
return op_trans
def convert_operator(self, O, ish=0):
""" Converts a second-quantization operator from sumk structure
to solver structure.
Parameters
----------
O : triqs.operators.Operator
Operator in sumk structure
ish : int
shell index on which the operator acts
"""
from triqs.operators import Operator, c, c_dag
T = self.transformation[ish]
sk2s = self.sumk_to_solver[ish]
O_out = Operator(0)
for monomial in O:
coefficient = monomial[-1]
new_monomial = Operator(1)
#if coefficient > 1e-10:
for single_operator in monomial[0]:
new_single_operator = Operator(0)
daggered = single_operator[0]
blockname = single_operator[1][0]
i = single_operator[1][1]
for j in range(len(T[blockname])):
if sk2s[(blockname, j)] != (None, None):
if daggered:
new_single_operator += (
T[blockname][j, i] *
c_dag(*sk2s[(blockname, j)]))
else:
new_single_operator += (
T[blockname][j, i].conjugate() *
c(*sk2s[(blockname, j)]))
new_monomial *= new_single_operator
O_out += new_monomial * coefficient
return O_out
def test_fundamental():
assert (op_is_fundamental(c(0, 0)) is True)
assert (op_is_fundamental(c_dag(0, 0)) is True)
assert (op_is_fundamental(c_dag(0, 0) * c(0, 0)) is False)
assert (op_is_fundamental(Operator(1.0)) is False)
assert (op_serialize_fundamental(c(0, 0)) == (False, (0, 0)))
assert (op_serialize_fundamental(c_dag(0, 0)) == (True, (0, 0)))
assert (op_serialize_fundamental(c(2, 4)) == (False, (2, 4)))
assert (op_serialize_fundamental(c_dag(4, 3)) == (True, (4, 3)))
def get_quadratic_operator(h, fundamental_operators):
# -- Check Hermicity
np.testing.assert_array_almost_equal(h, h.T.conj())
H = Operator(0.)
for idx1, o1 in enumerate(fundamental_operators):
o1 = dagger(o1)
for idx2, o2 in enumerate(fundamental_operators):
H += h[idx1, idx2] * o1 * o2
return H
def c_transf(s, i):
if (s, i) not in op_idx_set:
return c(s, i)
k = op_idx_map.index((s, i))
ret = Operator()
for l in range(U.shape[0]):
op_idx = op_idx_map[l]
ret += U[k, l] * c(*op_idx)
return ret
def operator_from_quartic_tensor(h_quart, fundamental_operators):
# -- Convert fundamental operators back and forth from index
op_idx_map = get_operator_index_map(fundamental_operators)
op_idx_set = set(op_idx_map)
nop = len(fundamental_operators)
H = Operator(0.)
for t in itertools.product(enumerate(fundamental_operators), repeat=4):
idx, ops = list(zip(*t))
o1, o2, o3, o4 = ops
o1, o2 = dagger(o1), dagger(o2)
H += h_quart[idx] * o1 * o2 * o3 * o4
return H
import unittest
from triqs.operators import c, c_dag, Operator
from triqs.atom_diag import *
from itertools import product
import numpy as np
orbs = (1, 2, 3)
spins = ("dn", "up")
# Construct a sum of the pair hopping and spin flip terms from a 3-orbital Kanamori interaction Hamiltonian
H_p = Operator()
H_J = Operator()
for o1, o2 in product(orbs, repeat=2):
if o1 == o2: continue
H_p += c_dag("dn", o1) * c_dag("up", o1) * c("up", o2) * c("dn", o2)
H_J += c_dag("dn", o1) * c("up", o1) * c_dag("up", o2) * c("dn", o2)
H = H_p + H_J
fops1 = [(s, o) for (s, o) in product(spins, orbs)]
fops2 = [(s, o) for (o, s) in product(orbs, spins)]
ad1 = AtomDiag(H, fops1)
ad2 = AtomDiag(H, fops2)
# for e1, e2 in zip(ad1.energies, ad2.energies):
# print(e1.round(5), e2.round(5))
def h_int_kanamori_d(spin_names,
orb_names,
U,
Uprime,
J_hund,
off_diag=None,
map_operator_structure=None,
H_dump=None,
d=None):
r"""
Create a Kanamori Hamiltonian using the density-density, spin-fip and pair-hopping interactions.
.. math::
H = \frac{1}{2} \sum_{(i \sigma) \neq (j \sigma')} U_{i j}^{\sigma \sigma'} n_{i \sigma} n_{j \sigma'}
- \sum_{i \neq j} J a^\dagger_{i \uparrow} a_{i \downarrow} a^\dagger_{j \downarrow} a_{j \uparrow}
+ \sum_{i \neq j} J a^\dagger_{i \uparrow} a^\dagger_{i \downarrow} a_{j \downarrow} a_{j \uparrow}.
Parameters
----------
spin_names : list of strings
Names of the spins, e.g. ['up','down'].
orb_names : list of strings or int
Names of the orbitals, e.g. [0,1,2] or ['t2g','eg'].
U : 2D matrix or array
:math:`U_{ij}^{\sigma \sigma} (same spins)`
Uprime : 2D matrix or array
:math:`U_{ij}^{\sigma \bar{\sigma}} (opposite spins)`
J_hund : scalar
:math:`J`
off_diag : boolean
Do we have (orbital) off-diagonal elements?
If yes, the operators and blocks are denoted by ('spin', 'orbital'),
otherwise by ('spin_orbital',0).
map_operator_structure : dict
Mapping of names of GF blocks names from one convention to another,
e.g. {('up', 0): ('up_0', 0), ('down', 0): ('down_0',0)}.
If provided, the operators and blocks are denoted by the mapping of ``('spin', 'orbital')``.
H_dump : string
Name of the file to which the Hamiltonian should be written.
Returns
-------
H : Operator
The Hamiltonian.
"""
def d_dag(b, m):
return dagger(d(b, m))
if H_dump:
H_dump_file = open(H_dump, 'w')
H_dump_file.write("Kanamori Hamiltonian:" + '\n')
H = Operator()
mkind = get_mkind(off_diag, map_operator_structure)
# density terms:
if H_dump: H_dump_file.write("Density-density terms:" + '\n')
for s1, s2 in product(spin_names, spin_names):
for a1, a2 in product(orb_names, orb_names):
if (s1 == s2):
U_val = U[orb_names.index(a1), orb_names.index(a2)]
else:
U_val = Uprime[orb_names.index(a1), orb_names.index(a2)]
H_term = 0.5 * U_val * d_dag(*mkind(s1, a1)) * d(
*mkind(s1, a1)) * d_dag(*mkind(s2, a2)) * d(*mkind(s2, a2))
H += H_term
# Dump terms of H
if H_dump and not H_term.is_zero():
H_dump_file.write('%s' % (mkind(s1, a1), ) + '\t')
H_dump_file.write('%s' % (mkind(s2, a2), ) + '\t')
H_dump_file.write(str(U_val) + '\n')
# spin-flip terms:
if H_dump: H_dump_file.write("Spin-flip terms:" + '\n')
for s1, s2 in product(spin_names, spin_names):
if (s1 == s2):
continue
for a1, a2 in product(orb_names, orb_names):
if (a1 == a2):
continue
H_term = -0.5 * J_hund * d_dag(*mkind(s1, a1)) * d(
*mkind(s2, a1)) * d_dag(*mkind(s2, a2)) * d(*mkind(s1, a2))
H += H_term
# Dump terms of H
if H_dump and not H_term.is_zero():
H_dump_file.write('%s' % (mkind(s1, a1), ) + '\t')
H_dump_file.write('%s' % (mkind(s2, a2), ) + '\t')
H_dump_file.write(str(-J_hund) + '\n')
# pair-hopping terms:
if H_dump: H_dump_file.write("Pair-hopping terms:" + '\n')
for s1, s2 in product(spin_names, spin_names):
if (s1 == s2):
continue
for a1, a2 in product(orb_names, orb_names):
if (a1 == a2):
continue
H_term = 0.5 * J_hund * d_dag(*mkind(s1, a1)) * d_dag(
*mkind(s2, a1)) * d(*mkind(s2, a2)) * d(*mkind(s1, a2))
H += H_term
# Dump terms of H
if H_dump and not H_term.is_zero():
H_dump_file.write('%s' % (mkind(s1, a1), ) + '\t')
H_dump_file.write('%s' % (mkind(s2, a2), ) + '\t')
H_dump_file.write(str(-J_hund) + '\n')
return H
def d(b, m):
ret = Operator()
for i in range(len(v[b])):
ret += v[b][m][i] * c(b, i)
return ret