def test_build_from_openfermion(self):
print('\n')
trial_state = qforte.QuantumComputer(4)
trial_prep = [None] * 5
trial_prep[0] = qforte.gate('H', 0, 0)
trial_prep[1] = qforte.gate('H', 1, 1)
trial_prep[2] = qforte.gate('H', 2, 2)
trial_prep[3] = qforte.gate('H', 3, 3)
trial_prep[4] = qforte.gate('cX', 0, 1)
trial_circ = qforte.QuantumCircuit()
#prepare the circuit
for gate in trial_prep:
trial_circ.add_gate(gate)
# use circuit to prepare trial state
trial_state.apply_circuit(trial_circ)
test_operator = QubitOperator('X2 Y1', 0.0 - 0.25j)
test_operator += QubitOperator('Y2 Y1', 0.25)
test_operator += QubitOperator('X2 X1', 0.25)
test_operator += QubitOperator('Y2 X1', 0.0 + 0.25j)
print(test_operator)
qforte_operator = qforte.build_from_openfermion(test_operator)
qforte.smart_print(qforte_operator)
exp = trial_state.direct_op_exp_val(qforte_operator)
print(exp)
self.assertAlmostEqual(exp, 0.2499999999999999 + 0.0j)
def add_singles(occ_idx, vir_idx):
for i in occ_idx:
for a in vir_idx:
single = FermionOperator(((a, 1), (i, 0)))
# 1. build Fermion anti-Hermitian operator
single -= hermitian_conjugated(single)
# 2. JW transformation to qubit operator
jw_single = jordan_wigner(single)
h_single_commutator = commutator(self.h_qubit_OF, jw_single)
# 3. qforte.build_from_openfermion(OF_qubitop)
qf_jw_single = qforte.build_from_openfermion(jw_single)
qf_commutator = qforte.build_from_openfermion(h_single_commutator)
self.fermion_ops.append((i,a))
self.jw_ops.append(qf_jw_single)
self.jw_commutators.append(qf_commutator)
def add_doubles(occ_idx_pairs, vir_idx_pairs):
for ji in occ_idx_pairs:
for ba in vir_idx_pairs:
j, i = ji
b, a = ba
double = FermionOperator(F'{a}^ {b}^ {i} {j}')
double -= hermitian_conjugated(double)
jw_double = jordan_wigner(double)
h_double_commutator = commutator(self.h_qubit_OF, jw_double)
qf_jw_double = qforte.build_from_openfermion(jw_double)
qf_commutator = qforte.build_from_openfermion(
h_double_commutator)
self.fermion_ops.append((j,i,b,a))
self.jw_ops.append(qf_jw_double)
self.jw_commutators.append(qf_commutator)
def get_qubit_hamitonian(self, docc_indices=None, active_orb_indices=None):
""" Return Hamiltonian operator as a qforte.QuantumOperator instance
Parameters
----------
docc_indices: list, optional
list of spatial orbital indices indicating which orbitals should be considered doubly occupied.
active_orb_indices: list, optional
list of spatial orbital indices indicating which orbitals should be considered active.
"""
# "molecular_hamiltonian": instance of the MolecularOperator class
molecular_hamiltonian = self.molecule.get_molecular_hamiltonian(
occupied_indices=docc_indices, active_indices=active_orb_indices)
h_fermion = normal_ordered(get_fermion_operator(molecular_hamiltonian))
h_qubit_OF = jordan_wigner(h_fermion)
h_qubit_qf = qforte.build_from_openfermion(h_qubit_OF)
return h_qubit_qf, h_qubit_OF