def test_fidelity_product_states(): a, b = cirq.LineQubit.range(2) np.testing.assert_allclose( cirq.fidelity(cirq.KET_ZERO(a) * cirq.KET_ZERO(b), cirq.KET_ZERO(a) * cirq.KET_ZERO(b)), 1.0 ) np.testing.assert_allclose( cirq.fidelity(cirq.KET_ZERO(a) * cirq.KET_ZERO(b), cirq.KET_ZERO(a) * cirq.KET_ONE(b)), 0.0, atol=1e-7, ) np.testing.assert_allclose( cirq.fidelity(cirq.KET_ZERO(a) * cirq.KET_ZERO(b), cirq.KET_ZERO(a) * cirq.KET_PLUS(b)), 0.5 ) np.testing.assert_allclose( cirq.fidelity(cirq.KET_ONE(a) * cirq.KET_ONE(b), cirq.KET_MINUS(a) * cirq.KET_PLUS(b)), 0.25 ) np.testing.assert_allclose( cirq.fidelity(cirq.KET_MINUS(a) * cirq.KET_PLUS(b), cirq.KET_MINUS(a) * cirq.KET_PLUS(b)), 1.0, ) np.testing.assert_allclose( cirq.fidelity(cirq.KET_MINUS(a) * cirq.KET_PLUS(b), cirq.KET_PLUS(a) * cirq.KET_MINUS(b)), 0.0, atol=1e-7, ) with pytest.raises(ValueError, match='Mismatched'): _ = cirq.fidelity(cirq.KET_MINUS(a), cirq.KET_PLUS(a) * cirq.KET_MINUS(b)) with pytest.raises(ValueError, match='qid shape'): _ = cirq.fidelity( cirq.KET_MINUS(a) * cirq.KET_PLUS(b), cirq.KET_PLUS(a) * cirq.KET_MINUS(b), qid_shape=(4,), )
def test_tp_projector(): q0, q1 = cirq.LineQubit.range(2) p00 = (cirq.KET_ZERO(q0) * cirq.KET_ZERO(q1)).projector() rho = cirq.final_density_matrix(cirq.Circuit(cirq.I.on_each(q0, q1))) np.testing.assert_allclose(rho, p00) p01 = (cirq.KET_ZERO(q0) * cirq.KET_ONE(q1)).projector() rho = cirq.final_density_matrix(cirq.Circuit([cirq.I.on_each(q0, q1), cirq.X(q1)])) np.testing.assert_allclose(rho, p01) ppp = (cirq.KET_PLUS(q0) * cirq.KET_PLUS(q1)).projector() rho = cirq.final_density_matrix( cirq.Circuit( [ cirq.H.on_each(q0, q1), ] ) ) np.testing.assert_allclose(rho, ppp, atol=1e-7) ppm = (cirq.KET_PLUS(q0) * cirq.KET_MINUS(q1)).projector() rho = cirq.final_density_matrix(cirq.Circuit([cirq.H.on_each(q0, q1), cirq.Z(q1)])) np.testing.assert_allclose(rho, ppm, atol=1e-7) pii = (cirq.KET_IMAG(q0) * cirq.KET_IMAG(q1)).projector() rho = cirq.final_density_matrix(cirq.Circuit(cirq.rx(-np.pi / 2).on_each(q0, q1))) np.testing.assert_allclose(rho, pii, atol=1e-7) pij = (cirq.KET_IMAG(q0) * cirq.KET_MINUS_IMAG(q1)).projector() rho = cirq.final_density_matrix(cirq.Circuit(cirq.rx(-np.pi / 2)(q0), cirq.rx(np.pi / 2)(q1))) np.testing.assert_allclose(rho, pij, atol=1e-7)
def test_tp_initial_state(): q0, q1 = cirq.LineQubit.range(2) psi1 = cirq.final_state_vector(cirq.Circuit([cirq.I.on_each(q0, q1), cirq.X(q1)])) s01 = cirq.KET_ZERO(q0) * cirq.KET_ONE(q1) psi2 = cirq.final_state_vector(cirq.Circuit([cirq.I.on_each(q0, q1)]), initial_state=s01) np.testing.assert_allclose(psi1, psi2)
def test_tp_state_vector(): q0, q1 = cirq.LineQubit.range(2) s00 = cirq.KET_ZERO(q0) * cirq.KET_ZERO(q1) np.testing.assert_equal(s00.state_vector(), [1, 0, 0, 0]) np.testing.assert_equal(s00.state_vector(qubit_order=(q1, q0)), [1, 0, 0, 0]) s01 = cirq.KET_ZERO(q0) * cirq.KET_ONE(q1) np.testing.assert_equal(s01.state_vector(), [0, 1, 0, 0]) np.testing.assert_equal(s01.state_vector(qubit_order=(q1, q0)), [0, 0, 1, 0])
def test_simulate_tps_initial_state(): q0, q1 = cirq.LineQubit.range(2) simulator = cirq.DensityMatrixSimulator() for b0 in [0, 1]: for b1 in [0, 1]: circuit = cirq.Circuit((cirq.X ** b0)(q0), (cirq.X ** b1)(q1)) result = simulator.simulate(circuit, initial_state=cirq.KET_ZERO(q0) * cirq.KET_ONE(q1)) expected_density_matrix = np.zeros(shape=(4, 4)) expected_density_matrix[b0 * 2 + 1 - b1, b0 * 2 + 1 - b1] = 1.0 np.testing.assert_equal(result.final_density_matrix, expected_density_matrix)
def test_quantum_state_product_state(): q0, q1, q2 = cirq.LineQubit.range(3) product_state_1 = cirq.KET_PLUS(q0) * cirq.KET_PLUS(q1) * cirq.KET_ONE(q2) state = cirq.quantum_state(product_state_1) np.testing.assert_allclose(state.data, product_state_1.state_vector()) assert state.qid_shape == (2, 2, 2) assert state.dtype == np.complex64 with pytest.raises(ValueError, match='qid shape'): _ = cirq.quantum_state(product_state_1, qid_shape=(2, 2))
def test_product_state(): q0, q1, q2 = cirq.LineQubit.range(3) ps = cirq.KET_PLUS(q0) * cirq.KET_PLUS(q1) assert str(ps) == "+X(0) * +X(1)" ps *= cirq.KET_ONE(q2) assert str(ps) == "+X(0) * +X(1) * -Z(2)" with pytest.raises(ValueError) as e: # Re-use q2 ps *= cirq.KET_PLUS(q2) assert e.match(r'.*both contain factors for these qubits: ' r'\[cirq.LineQubit\(2\)\]') ps2 = eval(repr(ps)) assert ps == ps2