def circuit(p, alpha, tampered_wire):
"""A quantum circuit that will be able to identify bitflip errors.
DO NOT MODIFY any already-written lines in this function.
Args:
p (float): The bit flip probability
alpha (float): The parameter used to calculate `density_matrix(alpha)`
tampered_wire (int): The wire that may or may not be flipped (zero-index)
Returns:
Some expectation value, state, probs, ... you decide!
"""
qml.QubitDensityMatrix(density_matrix(alpha), wires=[0, 1, 2])
# QHACK #
# put any input processing gates here
qml.CNOT(wires=(0,1))
qml.CNOT(wires=(0,2))
qml.BitFlip(p, wires=int(tampered_wire))
# put any gates here after the bitflip error has occurred
### No gates after bitflip
# return something!
return qml.density_matrix((0,1,2))
def circuit_without_tardigrade():
""" Circuit without Tardigrade
Prepares |010> + |100>
"""
qml.Hadamard(wires=0)
qml.PauliX(wires=1)
qml.CNOT(wires=(0, 1))
return qml.density_matrix(wires=1)
def circuit_with_tardigrade(theta):
""" Circuit with Tardigrade
Prepares cos(theta/2) |010> + sin(theta/2) |001> + |100>
"""
qml.Hadamard(wires=0)
qml.CRY(np.pi + theta, wires=(0, 1))
qml.CNOT(wires=(0, 2))
qml.CNOT(wires=(1, 2))
qml.PauliX(wires=0)
return qml.density_matrix(wires=1)
def circuit(inputs, w1, w2, w3, w4, w5, w6, w7):
"""Sample circuit to be used for testing density_matrix() return type."""
qml.templates.AngleEmbedding(inputs, wires=list(range(n_qubits)))
qml.templates.StronglyEntanglingLayers(w1, wires=list(range(n_qubits)))
qml.RX(w2[0], wires=0 % n_qubits)
qml.RX(w3, wires=1 % n_qubits)
qml.Rot(*w4, wires=2 % n_qubits)
qml.templates.StronglyEntanglingLayers(w5, wires=list(range(n_qubits)))
qml.Rot(*w6, wires=3 % n_qubits)
qml.RX(w7, wires=4 % n_qubits)
# Using np.log2() here because output_dim is sampled from varying the number of
# qubits (say, nq) and calculated as (2 ** nq, 2 ** nq)
return qml.density_matrix(wires=[i for i in range(int(np.log2(output_dim[0])))])
def func():
qml.Hadamard(0)
qml.CNOT(wires=[0, 1])
return qml.density_matrix(wires=[0, 1])
def circuit():
qml.Hadamard(wires=0)
qml.CNOT(wires=[0, 1])
qml.CRX(np.pi / 2, wires=[0, 1])
return qml.density_matrix(wires=[0])
def circuit(features, weights):
self.apply(features, weights)
return qml.density_matrix(self.wires)
