def test_get_quadratic_hamiltonian_not_hermitian(self):
"""Test non-Hermitian operators."""
with self.assertRaises(QuadraticHamiltonianError):
get_quadratic_hamiltonian(self.not_hermitian_1)
with self.assertRaises(QuadraticHamiltonianError):
get_quadratic_hamiltonian(self.not_hermitian_2)
with self.assertRaises(QuadraticHamiltonianError):
get_quadratic_hamiltonian(self.not_hermitian_3)
with self.assertRaises(QuadraticHamiltonianError):
get_quadratic_hamiltonian(self.not_hermitian_4)
with self.assertRaises(QuadraticHamiltonianError):
get_quadratic_hamiltonian(self.not_hermitian_5)
def test_ignore_incompatible_terms(self):
ferm_op = (FermionOperator('0^ 2') + FermionOperator('2^ 0') +
FermionOperator('1^ 0^ 2') + FermionOperator('1^ 0^ 2 1') +
FermionOperator('0^ 0 1^ 1') + FermionOperator('1^ 2^ 1 2'))
converted_op = get_quadratic_hamiltonian(
ferm_op, ignore_incompatible_terms=True)
self.assertTrue(
numpy.allclose(converted_op.hermitian_part,
numpy.array([[0, 0, 1], [0, 0, 0], [1, 0, 0]])))
def test_get_quadratic_hamiltonian_hermitian(self):
"""Test properly formed quadratic Hamiltonians."""
# Non-particle-number-conserving without chemical potential
quadratic_op = get_quadratic_hamiltonian(self.hermitian_op)
fermion_operator = get_fermion_operator(quadratic_op)
fermion_operator = normal_ordered(fermion_operator)
self.assertTrue(normal_ordered(self.hermitian_op) == fermion_operator)
# Non-particle-number-conserving chemical potential
quadratic_op = get_quadratic_hamiltonian(self.hermitian_op,
chemical_potential=3.)
fermion_operator = get_fermion_operator(quadratic_op)
fermion_operator = normal_ordered(fermion_operator)
self.assertTrue(normal_ordered(self.hermitian_op) == fermion_operator)
# Particle-number-conserving
quadratic_op = get_quadratic_hamiltonian(self.hermitian_op_pc)
fermion_operator = get_fermion_operator(quadratic_op)
fermion_operator = normal_ordered(fermion_operator)
self.assertTrue(
normal_ordered(self.hermitian_op_pc) == fermion_operator)
def test_get_quadratic_hamiltonian_too_few_qubits(self):
"""Test asking for too few qubits."""
with self.assertRaises(ValueError):
get_quadratic_hamiltonian(FermionOperator('3^ 2^'), n_qubits=3)
def test_get_quadratic_hamiltonian_bad_input(self):
"""Test improper input."""
with self.assertRaises(TypeError):
get_quadratic_hamiltonian('3')
def test_get_quadratic_hamiltonian_hermitian_bad_term(self):
"""Test an operator with non-quadratic terms."""
with self.assertRaises(QuadraticHamiltonianError):
get_quadratic_hamiltonian(self.hermitian_op_bad_term)
