def quantum_teleportation(alice_state):
# Get operators we will need
CNOT = qc.CNOT()
H = qc.Hadamard()
X = qc.PauliX()
Z = qc.PauliZ()
# The prepared, shared Bell state
bell = qc.bell_state(0, 0)
# The whole state vector
state = alice_state * bell
# Apply CNOT and Hadamard gate
state = CNOT(state, qubit_indices=[0, 1])
state = H(state, qubit_indices=[0])
# Measure the first two bits
# The only uncollapsed part of the state vector is Bob's
M1, M2 = state.measure(qubit_indices=[0, 1], remove=True)
# Apply X and/or Z gates to third qubit depending on measurements
if M2:
state = X(state)
if M1:
state = Z(state)
return state
def test_CNOT_hadamard_identity(self):
C = qc.CNOT()
H = qc.Hadamard()
C1 = (H * H)(C(H * H, qubit_indices=[1, 0]))
self.assertLess(max_absolute_difference(C, C1), epsilon)
def test_CNOT_swap_identity(self):
C = qc.CNOT()
Sw = qc.Swap()
Sw1 = C(C(C, qubit_indices=[1, 0]))
self.assertLess(
max_absolute_difference(
Sw, Sw1), epsilon)
def bell_state(x, y):
H = qc.Hadamard()
CNOT = qc.CNOT()
phi = qc.bitstring(x, y)
phi = H(phi, qubit_indices=[0])
return CNOT(phi)
def test_squared_equals_I(self):
for Op_type in self.squared_equals_I_list:
I = qc.Identity()
U = Op_type()
diff = max_absolute_difference(U(U), I)
self.assertLess(diff, epsilon)
I = qc.Identity(2)
C = qc.CNOT()
self.assertLess(max_absolute_difference(C(C), I), epsilon)
def superdense_coding(bit_1, bit_2):
# Get operators we will need
CNOT = qc.CNOT()
H = qc.Hadamard()
X = qc.PauliX()
Z = qc.PauliZ()
# The prepared, shared Bell state
# Initially, half is in Alice's possession, and half in Bob's
phi = qc.bell_state(0, 0)
# Alice manipulates her qubit
if bit_2:
phi = X(phi, qubit_indices=[0])
if bit_1:
phi = Z(phi, qubit_indices=[0])
# Bob decodes the two bits
phi = CNOT(phi)
phi = H(phi, qubit_indices=[0])
measurements = phi.measure()
return measurements