def test_phase_calibrated_fsim_gate_as_characterized_phased_fsim_gate(
phase_exponent: float):
a, b = cirq.LineQubit.range(2)
ideal_gate = cirq.FSimGate(theta=np.pi / 4, phi=0.0)
characterized_gate = cirq.PhasedFSimGate(theta=ideal_gate.theta,
zeta=0.1,
chi=0.2,
gamma=0.3,
phi=ideal_gate.phi)
parameters = PhasedFSimCharacterization(
theta=ideal_gate.theta,
zeta=characterized_gate.zeta,
chi=characterized_gate.chi,
gamma=characterized_gate.gamma,
phi=ideal_gate.phi,
)
calibrated = PhaseCalibratedFSimGate(ideal_gate,
phase_exponent=phase_exponent)
phased_gate = calibrated.as_characterized_phased_fsim_gate(parameters).on(
a, b)
assert np.allclose(
cirq.unitary(phased_gate),
cirq.unitary(
cirq.Circuit([
[cirq.Z(a)**-phase_exponent,
cirq.Z(b)**phase_exponent],
characterized_gate.on(a, b),
[cirq.Z(a)**phase_exponent,
cirq.Z(b)**-phase_exponent],
])),
)
def create_gate_with_drift(
self, a: cirq.Qid, b: cirq.Qid, gate_calibration: PhaseCalibratedFSimGate
) -> cirq.PhasedFSimGate:
"""Generates a gate with drift for a given gate.
Args:
a: The first qubit.
b: The second qubit.
gate_calibration: Reference gate together with a phase information.
Returns:
A modified gate that includes the drifts induced by internal state of the simulator.
"""
gate = gate_calibration.engine_gate
if (a, b, gate) in self._drifted_parameters:
parameters = self._drifted_parameters[(a, b, gate)]
elif (b, a, gate) in self._drifted_parameters:
parameters = self._drifted_parameters[(b, a, gate)].parameters_for_qubits_swapped()
else:
parameters = self._drift_generator(a, b, gate)
self._drifted_parameters[(a, b, gate)] = parameters
return gate_calibration.as_characterized_phased_fsim_gate(parameters)
