def test_invalid_state_distinguishability_probs():
"""Invalid probability vector for state distinguishability."""
with np.testing.assert_raises(ValueError):
rho1 = bell(0) * bell(0).conj().T
rho2 = bell(1) * bell(1).conj().T
states = [rho1, rho2]
state_distinguishability(states, [1, 2, 3])
def test_state_distinguishability_one_state():
"""State distinguishability for single state."""
rho = bell(0) * bell(0).conj().T
states = [rho]
res = state_distinguishability(states)
np.testing.assert_equal(np.isclose(res, 1), True)
def test_state_distinguishability_three_state_vec():
"""State distinguishability for two state vectors."""
e_0, e_1 = basis(2, 0), basis(2, 1)
states = [e_0, e_1]
probs = [1 / 2, 1 / 2]
res = state_distinguishability(states, probs)
np.testing.assert_equal(np.isclose(res, 1), True)
def test_unambiguous_state_distinguishability_two_states():
"""Unambiguous state distinguishability for two state density matrices."""
e_0, e_1 = basis(2, 0), basis(2, 1)
e_00 = e_0 * e_0.conj().T
e_11 = e_1 * e_1.conj().T
states = [e_00, e_11]
probs = [1 / 2, 1 / 2]
res = state_distinguishability(states, probs, dist_method="unambiguous")
np.testing.assert_equal(np.isclose(res, 1), True)
def test_state_distinguishability_yyd_density_matrices():
"""Global distinguishability of the YYD states should yield 1."""
psi0 = bell(0) * bell(0).conj().T
psi1 = bell(1) * bell(1).conj().T
psi2 = bell(2) * bell(2).conj().T
psi3 = bell(3) * bell(3).conj().T
states = [
np.kron(psi0, psi0),
np.kron(psi2, psi1),
np.kron(psi3, psi1),
np.kron(psi1, psi1),
]
probs = [1 / 4, 1 / 4, 1 / 4, 1 / 4]
res = state_distinguishability(states, probs)
np.testing.assert_equal(np.isclose(res, 1, atol=0.001), True)
def test_invalid_state_distinguishability_states():
"""Invalid number of states for state distinguishability."""
with np.testing.assert_raises(ValueError):
states = []
state_distinguishability(states)