Json serialize cirq.ion.ion_gates.MSGate #4603
Description
Replace the existing class:
Cirq/cirq-core/cirq/ion/ion_gates.py
Line 27 in ec9fc45
with
class MSGate(ops.XXPowGate):
"""The Mølmer–Sørensen gate, a native two-qubit operation in ion traps.
A rotation around the XX axis in the two-qubit bloch sphere.
The gate implements the following unitary:
exp(-i t XX) = [ cos(t) 0 0 -isin(t)]
[ 0 cos(t) -isin(t) 0 ]
[ 0 -isin(t) cos(t) 0 ]
[-isin(t) 0 0 cos(t) ]
"""
def __init__(self, *, rads: float): # Forces keyword args.
ops.XXPowGate.__init__(self, exponent=rads * 2 / np.pi, global_shift=-0.5)
self.rads = rads
def _with_exponent(self: 'MSGate', exponent: value.TParamVal) -> 'MSGate':
return type(self)(rads=exponent * np.pi / 2)
def _circuit_diagram_info_(
self, args: 'cirq.CircuitDiagramInfoArgs'
) -> Union[str, 'protocols.CircuitDiagramInfo']:
angle_str = self._format_exponent_as_angle(args, order=4)
symbol = f'MS({angle_str})'
return protocols.CircuitDiagramInfo(wire_symbols=(symbol, symbol))
def __str__(self) -> str:
if self._exponent == 1:
return 'MS(π/2)'
return f'MS({self._exponent!r}π/2)'
def __repr__(self) -> str:
if self._exponent == 1:
return 'cirq.ms(np.pi/2)'
return f'cirq.ms({self._exponent!r}*np.pi/2)'
def _json_dict_(self) -> Dict[str, Any]:
return cirq.protocols.obj_to_dict_helper(self, ["rads"])
@classmethod
def _from_json_dict_(cls, rads: float, **kwargs: Any) -> Any:
return cls(rads=rads)