def test_squeezed_fidelity(self, setup_backend, cutoff, tol, hbar):
backend = setup_backend(2)
backend.prepare_squeezed_state(r, phi, 0)
backend.squeeze(r, phi, 1)
state = backend.state()
if isinstance(backend, backends.BaseFock):
in_state = utils.squeezed_state(r, phi, basis="fock", fock_dim=cutoff, hbar=hbar)
else:
in_state = utils.squeezed_state(r, phi, 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)
def test_squeezed(self, r, phi, setup_eng, hbar, tol):
"""Test squeezed function matches Gaussian backends"""
eng, prog = setup_eng(1)
with prog.context as q:
ops.Sgate(r, phi) | q[0]
state = eng.run(prog).state
mu, cov = utils.squeezed_state(r, phi, 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_squeezed_state_fock(self, r, phi, cutoff, hbar, tol):
"""test squeezed state returns correct Fock basis state vector"""
state = utils.squeezed_state(r, phi, basis="fock", fock_dim=cutoff, hbar=hbar)
n = np.arange(cutoff)
kets = (np.sqrt(fac(2 * (n // 2))) / (2 ** (n // 2) * fac(n // 2))) * (
-np.exp(1j * phi) * np.tanh(r)
) ** (n // 2)
expected = np.where(n % 2 == 0, np.sqrt(1 / np.cosh(r)) * kets, 0)
assert np.allclose(state, expected, atol=tol, rtol=0)
def test_squeezed(self, r, phi, setup_eng, hbar, tol):
"""Test squeezed function matches Gaussian backends"""
eng, prog = setup_eng(1)
with prog.context as q:
ops.Sgate(r, phi) | q[0]
state = eng.run(prog)
mu, cov = utils.squeezed_state(r, phi, 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_squeezed(self, setup_eng, cutoff, hbar, tol):
eng, prog = setup_eng(3)
r = 0.05
phi = 0
cov = (hbar / 2) * np.diag([np.exp(-2 * r)] * 3 + [np.exp(2 * r)] * 3)
in_state = squeezed_state(r, phi, basis="fock", fock_dim=cutoff)
with prog.context as q:
ops.Gaussian(cov) | q
state = eng.run(prog).state
assert len(eng.run_progs[-1]) == 3
for n in range(3):
assert np.allclose(state.fidelity(in_state, n), 1, atol=tol)
def test_squeezed(self, setup_eng, cutoff, hbar, tol):
eng, q = setup_eng(3)
r = 0.05
phi = 0
cov = (hbar / 2) * np.diag([np.exp(-2 * r)] * 3 + [np.exp(2 * r)] * 3)
in_state = squeezed_state(r, phi, basis="fock", fock_dim=cutoff)
with eng:
ops.Gaussian(cov) | q
state = eng.run()
assert len(eng.cmd_applied[0]) == 3
for n in range(3):
assert np.allclose(state.fidelity(in_state, n), 1, atol=tol)
def test_squeezed_state_gaussian(self, r, phi, hbar, tol):
"""test squeezed state returns correct means and covariance"""
means, cov = utils.squeezed_state(r, phi, basis="gaussian", hbar=hbar)
cov_expected = (hbar / 2) * np.array([
[
np.cosh(2 * r) - np.cos(phi) * np.sinh(2 * r),
-2 * np.cosh(r) * np.sin(phi) * np.sinh(r),
],
[
-2 * np.cosh(r) * np.sin(phi) * np.sinh(r),
np.cosh(2 * r) + np.cos(phi) * np.sinh(2 * r),
],
])
assert np.all(means == np.zeros([2]))
assert np.allclose(cov, cov_expected, atol=tol, rtol=0)
def test_rotated_squeezed(self, setup_eng, cutoff, hbar, tol):
eng, q = setup_eng(3)
r = 0.1
phi = 0.2312
in_state = squeezed_state(r, phi, basis="fock", fock_dim=cutoff)
v1 = (hbar / 2) * np.diag([np.exp(-2 * r), np.exp(2 * r)])
A = changebasis(3)
cov = A.T @ block_diag(*[rot(phi) @ v1 @ rot(phi).T] * 3) @ A
with eng:
ops.Gaussian(cov) | q
state = eng.run()
assert len(eng.cmd_applied[0]) == 3
for n in range(3):
assert np.allclose(state.fidelity(in_state, n), 1, atol=tol)
def test_rotated_squeezed(self, setup_eng, cutoff, hbar, tol):
eng, prog = setup_eng(3)
r = 0.1
phi = 0.2312
in_state = squeezed_state(r, phi, basis="fock", fock_dim=cutoff)
v1 = (hbar / 2) * np.diag([np.exp(-2 * r), np.exp(2 * r)])
cov = xpxp_to_xxpp(block_diag(*[rot(phi) @ v1 @ rot(phi).T] * 3))
with prog.context as q:
ops.Gaussian(cov) | q
state = eng.run(prog).state
assert len(eng.run_progs[-1]) == 3
for n in range(3):
assert np.allclose(state.fidelity(in_state, n), 1, atol=tol)
def test_squeezed(self, setup_eng, hbar, cutoff, bsize, pure, tol):
"""Test squeezed function matches Fock backends"""
eng, prog = setup_eng(1)
r = 0.112
phi = 0.123
with prog.context as q:
ops.Sgate(r, phi) | q[0]
state = eng.run(prog).state
ket = utils.squeezed_state(r,
phi,
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)
