Ejemplo n.º 1
0
    def test_3d2_with_spin(self):
        dimension = 3
        grid_length = 2
        n_spatial_orbitals = grid_length**dimension
        wigner_seitz_radius = 9.3

        spinless = False
        n_qubits = n_spatial_orbitals
        if not spinless:
            n_qubits *= 2
        n_particles_big = 9

        length_scale = wigner_seitz_length_scale(wigner_seitz_radius,
                                                 n_particles_big, dimension)

        self.grid3 = Grid(dimension, grid_length, length_scale)
        # Get the occupied orbitals of the plane-wave basis Hartree-Fock state.
        hamiltonian = jellium_model(self.grid3, spinless, plane_wave=True)
        hamiltonian = normal_ordered(hamiltonian)
        hamiltonian.compress()

        occupied_states = numpy.array(
            lowest_single_particle_energy_states(hamiltonian, n_particles_big))
        self.hf_state_index3 = numpy.sum(2**occupied_states)

        self.hf_state3 = csc_matrix(([1.0], ([self.hf_state_index3], [0])),
                                    shape=(2**n_qubits, 1))

        self.orbital_occupations3 = [
            digit == '1' for digit in bin(self.hf_state_index3)[2:]
        ][::-1]
        self.occupied_orbitals3 = [
            index for index, occupied in enumerate(self.orbital_occupations3)
            if occupied
        ]

        self.reversed_occupied_orbitals3 = list(self.occupied_orbitals3)
        for i in range(len(self.reversed_occupied_orbitals3)):
            self.reversed_occupied_orbitals3[i] = -1 + int(
                numpy.log2(self.hf_state3.shape[0])
            ) - self.reversed_occupied_orbitals3[i]

        self.reversed_hf_state_index3 = sum(
            2**index for index in self.reversed_occupied_orbitals3)

        operator = (FermionOperator('4^ 2^ 3^ 5 5 4', 2) +
                    FermionOperator('7^ 6^ 7 4', -3.7j) +
                    FermionOperator('3^ 7', 2.1))
        operator = normal_ordered(operator)
        transformed_operator = normal_ordered(
            fourier_transform(operator, self.grid3, spinless))

        expected = -0.2625 - 0.578125j
        # Calculated from expected = expectation(get_sparse_operator(
        #    transformed_operator), self.hf_state3)
        actual = expectation_db_operator_with_pw_basis_state(
            operator, self.reversed_occupied_orbitals3, n_spatial_orbitals,
            self.grid3, spinless)

        self.assertAlmostEqual(expected, actual)
Ejemplo n.º 2
0
    def setUp(self):
        grid_length = 4
        dimension = 1
        wigner_seitz_radius = 10.
        self.spinless = True
        self.n_spatial_orbitals = grid_length**dimension

        n_qubits = self.n_spatial_orbitals
        self.n_particles = 3

        # Compute appropriate length scale and the corresponding grid.
        length_scale = wigner_seitz_length_scale(wigner_seitz_radius,
                                                 self.n_particles, dimension)

        self.grid1 = Grid(dimension, grid_length, length_scale)
        # Get the occupied orbitals of the plane-wave basis Hartree-Fock state.
        hamiltonian = jellium_model(self.grid1, self.spinless, plane_wave=True)
        hamiltonian = normal_ordered(hamiltonian)
        hamiltonian.compress()

        occupied_states = numpy.array(
            lowest_single_particle_energy_states(hamiltonian,
                                                 self.n_particles))
        self.hf_state_index1 = numpy.sum(2**occupied_states)

        self.hf_state1 = csc_matrix(([1.0], ([self.hf_state_index1], [0])),
                                    shape=(2**n_qubits, 1))

        self.orbital_occupations1 = [
            digit == '1' for digit in bin(self.hf_state_index1)[2:]
        ][::-1]
        self.occupied_orbitals1 = [
            index for index, occupied in enumerate(self.orbital_occupations1)
            if occupied
        ]

        self.reversed_occupied_orbitals1 = list(self.occupied_orbitals1)
        for i in range(len(self.reversed_occupied_orbitals1)):
            self.reversed_occupied_orbitals1[i] = -1 + int(
                numpy.log2(self.hf_state1.shape[0])
            ) - self.reversed_occupied_orbitals1[i]

        self.reversed_hf_state_index1 = sum(
            2**index for index in self.reversed_occupied_orbitals1)