Add single-qubit detuning parameters to CouplerPulse (#5971)

* Add single-qubit detuning parameters to CouplerPulse

* Update test json data with new coupler detune parameters.

* Add test to confirm that deserialization continues to work with added fields.

* Fix formatting

Co-authored-by: Matthew Neeley <maffoo@google.com>

cirq-google/cirq_google/experimental/ops/coupler_pulse.py

@@ -47,6 +47,8 @@ class CouplerPulse(cirq.ops.Gate):
             coupling_mhz: Target qubit-qubit coupling reached at the plateau.
             rise_time: Width of the rising (or falling) section of the trapezoidal pulse.
             padding_time: Symmetric padding around the coupler pulse.
+            q0_detune_mhz: Detuning of the first qubit.
+            q1_detune_mhz: Detuning of the second qubit.
     """
 
     def __init__(
@@ -55,6 +57,8 @@ def __init__(
         coupling_mhz: cirq.TParamVal,
         rise_time: Optional[cirq.Duration] = cirq.Duration(nanos=8),
         padding_time: Optional[cirq.Duration] = cirq.Duration(nanos=2.5),
+        q0_detune_mhz: cirq.TParamVal = 0.0,
+        q1_detune_mhz: cirq.TParamVal = 0.0,
     ):
         """Inits CouplerPulse.
 
@@ -63,12 +67,16 @@ def __init__(
             coupling_mhz: Target qubit-qubit coupling reached at the plateau.
             rise_time: Width of the rising (or falling) action of the trapezoidal pulse.
             padding_time: Symmetric padding around the coupler pulse.
+            q0_detune_mhz: Detuning of the first qubit.
+            q1_detune_mhz: Detuning of the second qubit.
 
         """
         self.hold_time = hold_time
         self.coupling_mhz = coupling_mhz
         self.rise_time = rise_time or cirq.Duration(nanos=8)
         self.padding_time = padding_time or cirq.Duration(nanos=2.5)
+        self.q0_detune_mhz = q0_detune_mhz
+        self.q1_detune_mhz = q1_detune_mhz
 
     def num_qubits(self) -> int:
         return 2
@@ -79,18 +87,22 @@ def _unitary_(self) -> np.ndarray:
     def __repr__(self) -> str:
         return (
             'cirq_google.experimental.ops.coupler_pulse.'
-            + f'CouplerPulse(hold_time={proper_repr(self.hold_time)}, '
-            + f'coupling_mhz={proper_repr(self.coupling_mhz)}, '
-            + f'rise_time={proper_repr(self.rise_time)}, '
-            + f'padding_time={proper_repr(self.padding_time)})'
+            f'CouplerPulse(hold_time={proper_repr(self.hold_time)}, '
+            f'coupling_mhz={proper_repr(self.coupling_mhz)}, '
+            f'rise_time={proper_repr(self.rise_time)}, '
+            f'padding_time={proper_repr(self.padding_time)}, '
+            f'q0_detune_mhz={proper_repr(self.q0_detune_mhz)}, '
+            f'q1_detune_mhz={proper_repr(self.q1_detune_mhz)})'
         )
 
     def __str__(self) -> str:
         return (
             f'CouplerPulse(hold_time={self.hold_time}, '
-            + f'coupling_mhz={self.coupling_mhz}, '
-            + f'rise_time={self.rise_time}, '
-            + f'padding_time={self.padding_time})'
+            f'coupling_mhz={self.coupling_mhz}, '
+            f'rise_time={self.rise_time}, '
+            f'padding_time={self.padding_time}, '
+            f'q0_detune_mhz={self.q0_detune_mhz}, '
+            f'q1_detune_mhz={self.q1_detune_mhz})'
         )
 
     def _is_parameterized_(self) -> bool:
@@ -99,6 +111,8 @@ def _is_parameterized_(self) -> bool:
             or cirq.is_parameterized(self.coupling_mhz)
             or cirq.is_parameterized(self.rise_time)
             or cirq.is_parameterized(self.padding_time)
+            or cirq.is_parameterized(self.q0_detune_mhz)
+            or cirq.is_parameterized(self.q1_detune_mhz)
         )
 
     def _parameter_names_(self: Any) -> AbstractSet[str]:
@@ -107,6 +121,8 @@ def _parameter_names_(self: Any) -> AbstractSet[str]:
             | cirq.parameter_names(self.coupling_mhz)
             | cirq.parameter_names(self.rise_time)
             | cirq.parameter_names(self.padding_time)
+            | cirq.parameter_names(self.q0_detune_mhz)
+            | cirq.parameter_names(self.q1_detune_mhz)
         )
 
     def _resolve_parameters_(
@@ -117,16 +133,37 @@ def _resolve_parameters_(
             coupling_mhz=cirq.resolve_parameters(self.coupling_mhz, resolver, recursive=recursive),
             rise_time=cirq.resolve_parameters(self.rise_time, resolver, recursive=recursive),
             padding_time=cirq.resolve_parameters(self.padding_time, resolver, recursive=recursive),
+            q0_detune_mhz=cirq.resolve_parameters(
+                self.q0_detune_mhz, resolver, recursive=recursive
+            ),
+            q1_detune_mhz=cirq.resolve_parameters(
+                self.q1_detune_mhz, resolver, recursive=recursive
+            ),
         )
 
     def _value_equality_values_(self) -> Any:
-        return self.hold_time, self.coupling_mhz, self.rise_time, self.padding_time
+        return (
+            self.hold_time,
+            self.coupling_mhz,
+            self.rise_time,
+            self.padding_time,
+            self.q0_detune_mhz,
+            self.q1_detune_mhz,
+        )
 
     def _circuit_diagram_info_(self, args: cirq.CircuitDiagramInfoArgs) -> Tuple[str, ...]:
         s = f'/‾‾({self.hold_time}@{self.coupling_mhz}MHz)‾‾\\'
         return (s, s)
 
     def _json_dict_(self):
         return cirq.obj_to_dict_helper(
-            self, ['hold_time', 'coupling_mhz', 'rise_time', 'padding_time']
+            self,
+            [
+                'hold_time',
+                'coupling_mhz',
+                'rise_time',
+                'padding_time',
+                'q0_detune_mhz',
+                'q1_detune_mhz',
+            ],
         )

cirq-google/cirq_google/experimental/ops/coupler_pulse_test.py

@@ -86,20 +86,47 @@ def test_coupler_pulse_str_repr():
         hold_time=cirq.Duration(nanos=10), coupling_mhz=25.0, rise_time=cirq.Duration(nanos=18)
     )
     assert (
-        str(gate)
-        == 'CouplerPulse(hold_time=10 ns, coupling_mhz=25.0, '
-        + 'rise_time=18 ns, padding_time=2500.0 ps)'
+        str(gate) == 'CouplerPulse(hold_time=10 ns, coupling_mhz=25.0, '
+        'rise_time=18 ns, padding_time=2500.0 ps, q0_detune_mhz=0.0, q1_detune_mhz=0.0)'
     )
     assert (
-        repr(gate)
-        == 'cirq_google.experimental.ops.coupler_pulse.CouplerPulse('
-        + 'hold_time=cirq.Duration(nanos=10), '
-        + 'coupling_mhz=25.0, '
-        + 'rise_time=cirq.Duration(nanos=18), '
-        + 'padding_time=cirq.Duration(picos=2500.0))'
+        repr(gate) == 'cirq_google.experimental.ops.coupler_pulse.CouplerPulse('
+        'hold_time=cirq.Duration(nanos=10), '
+        'coupling_mhz=25.0, '
+        'rise_time=cirq.Duration(nanos=18), '
+        'padding_time=cirq.Duration(picos=2500.0), '
+        'q0_detune_mhz=0.0, '
+        'q1_detune_mhz=0.0)'
     )
 
 
+def test_coupler_pulse_json_deserialization_defaults_on_missing_fields():
+    gate = coupler_pulse.CouplerPulse(
+        hold_time=cirq.Duration(nanos=10), coupling_mhz=25.0, rise_time=cirq.Duration(nanos=18)
+    )
+    json_text = """{
+       "cirq_type": "CouplerPulse",
+       "hold_time": {
+         "cirq_type": "Duration",
+         "picos": 10000
+       },
+       "coupling_mhz": 25.0,
+       "rise_time": {
+         "cirq_type": "Duration",
+         "picos": 18000
+       },
+       "padding_time": {
+         "cirq_type": "Duration",
+         "picos": 2500.0
+       }
+    }"""
+
+    deserialized = cirq.read_json(json_text=json_text)
+
+    assert deserialized == gate
+    assert deserialized.q0_detune_mhz == 0.0
+
+
 def test_coupler_pulse_circuit_diagram():
     a, b = cirq.LineQubit.range(2)
     gate = coupler_pulse.CouplerPulse(

cirq-google/cirq_google/json_test_data/CouplerPulse.json

@@ -12,5 +12,7 @@
   "padding_time": {
     "cirq_type": "Duration",
     "picos": 2500.0
-  }
+  },
+  "q0_detune_mhz": 0.0,
+  "q1_detune_mhz": 0.0
 }