def test_coherent(self, a, setup_eng, hbar, tol):
"""Test coherent function matches Gaussian backends"""
eng, prog = setup_eng(1)
with prog.context as q:
ops.Dgate(np.abs(a), np.angle(a)) | q[0]
state = eng.run(prog).state
mu, cov = utils.coherent_state(np.abs(a),
np.angle(a),
basis="gaussian",
hbar=hbar)
if eng.backend_name == "gassian":
mu_exp, cov_exp = state.reduced_gaussian(0)
assert np.allclose(mu, mu_exp, atol=tol, rtol=0)
assert np.allclose(cov, cov_exp, atol=tol, rtol=0)
elif eng.backend_name == "bosonic":
_, mu_exp, cov_exp = state.reduced_bosonic(0)
assert np.allclose(np.expand_dims(mu, axis=0),
mu_exp,
atol=tol,
rtol=0)
assert np.allclose(np.expand_dims(cov, axis=0),
cov_exp,
atol=tol,
rtol=0)
def test_coherent_state_gaussian(self, r_d, phi_d, hbar):
"""test coherent state returns correct means and covariance"""
means, cov = utils.coherent_state(r_d, phi_d, basis="gaussian", hbar=hbar)
alpha = r_d * np.exp(1j * phi_d)
means_expected = np.array([alpha.real, alpha.imag]) * np.sqrt(2 * hbar)
assert np.all(means == means_expected)
assert np.all(cov == np.identity(2) * hbar / 2)
def test_coherent_state_fock(self, r_d, phi_d, cutoff, hbar, tol):
"""test coherent state returns correct Fock basis state vector"""
state = utils.coherent_state(r_d, phi_d, basis="fock", fock_dim=cutoff, hbar=hbar)
n = np.arange(cutoff)
alpha = r_d * np.exp(1j * phi_d)
expected = np.exp(-0.5 * np.abs(alpha) ** 2) * alpha ** n / np.sqrt(fac(n))
assert np.allclose(state, expected, atol=tol, rtol=0)
def test_coherent_fidelity(self, setup_backend, cutoff, tol, hbar):
backend = setup_backend(2)
backend.prepare_coherent_state(np.abs(a), np.angle(a), 0)
backend.displacement(np.abs(a), np.angle(a), 1)
state = backend.state()
if isinstance(backend, backends.BaseFock):
in_state = utils.coherent_state(
np.abs(a), np.angle(a), basis="fock", fock_dim=cutoff, hbar=hbar
)
else:
in_state = utils.coherent_state(np.abs(a), np.angle(a), basis="gaussian", hbar=hbar)
assert np.allclose(state.fidelity(in_state, 0), 1, atol=tol, rtol=0)
assert np.allclose(state.fidelity(in_state, 1), 1, atol=tol, rtol=0)
assert np.allclose(state.fidelity_coherent([a, a]), 1, atol=tol, rtol=0)
def test_coherent(self, a, setup_eng, hbar, tol):
"""Test coherent function matches Gaussian backends"""
eng, prog = setup_eng(1)
with prog.context as q:
ops.Dgate(a) | q[0]
state = eng.run(prog)
mu, cov = utils.coherent_state(a, basis="gaussian", hbar=hbar)
mu_exp, cov_exp = state.reduced_gaussian(0)
assert np.allclose(mu, mu_exp, atol=tol, rtol=0)
assert np.allclose(cov, cov_exp, atol=tol, rtol=0)
def test_coherent(self, setup_eng, hbar, cutoff, bsize, pure, tol):
"""Test coherent function matches Fock backends"""
eng, prog = setup_eng(1)
a = 0.32 + 0.1j
with prog.context as q:
ops.Dgate(a) | q[0]
state = eng.run(prog).state
ket = utils.coherent_state(a, basis="fock", fock_dim=cutoff, hbar=hbar)
if not pure:
expected = state.dm()
ket = np.tile(np.outer(ket, ket.conj()), (bsize, 1, 1))
else:
expected = state.ket()
ket = np.tile(ket, (bsize, 1))
assert np.allclose(expected, ket, atol=tol, rtol=0)
