update parallel XEB methods to support circuits instead of single gates

cirq-core/cirq/experiments/random_quantum_circuit_generation.py

@@ -242,6 +242,36 @@ def random_rotations_between_two_qubit_circuit(
     return circuit
 
 
+def _generate_library_of_2q_circuits(
+    n_library_circuits: int,
+    two_qubit_op_factory: Callable[
+        ['cirq.Qid', 'cirq.Qid', 'np.random.RandomState'], 'cirq.OP_TREE'
+    ] = lambda a, b, _: ops.CZPowGate()(a, b),
+    *,
+    max_cycle_depth: int = 100,
+    q0: 'cirq.Qid' = devices.LineQubit(0),
+    q1: 'cirq.Qid' = devices.LineQubit(1),
+    random_state: 'cirq.RANDOM_STATE_OR_SEED_LIKE' = None,
+):
+    rs = value.parse_random_state(random_state)
+    exponents = np.linspace(0, 7 / 4, 8)
+    single_qubit_gates = [
+        ops.PhasedXZGate(x_exponent=0.5, z_exponent=z, axis_phase_exponent=a)
+        for a, z in itertools.product(exponents, repeat=2)
+    ]
+    return [
+        random_rotations_between_two_qubit_circuit(
+            q0,
+            q1,
+            depth=max_cycle_depth,
+            two_qubit_op_factory=two_qubit_op_factory,
+            single_qubit_gates=single_qubit_gates,
+            seed=rs,
+        )
+        for _ in range(n_library_circuits)
+    ]
+
+
 def generate_library_of_2q_circuits(
     n_library_circuits: int,
     two_qubit_gate: 'cirq.Gate',
@@ -269,23 +299,59 @@ def generate_library_of_2q_circuits(
         random_state: A random state or seed used to deterministically sample the random circuits.
         tags: Tags to add to the two qubit operations.
     """
-    rs = value.parse_random_state(random_state)
-    exponents = np.linspace(0, 7 / 4, 8)
-    single_qubit_gates = [
-        ops.PhasedXZGate(x_exponent=0.5, z_exponent=z, axis_phase_exponent=a)
-        for a, z in itertools.product(exponents, repeat=2)
-    ]
-    return [
-        random_rotations_between_two_qubit_circuit(
-            q0,
-            q1,
-            depth=max_cycle_depth,
-            two_qubit_op_factory=lambda a, b, _: two_qubit_gate(a, b).with_tags(*tags),
-            single_qubit_gates=single_qubit_gates,
-            seed=rs,
-        )
-        for _ in range(n_library_circuits)
-    ]
+    two_qubit_op_factory = lambda a, b, _: two_qubit_gate(a, b).with_tags(*tags)
+    return _generate_library_of_2q_circuits(
+        n_library_circuits=n_library_circuits,
+        two_qubit_op_factory=two_qubit_op_factory,
+        max_cycle_depth=max_cycle_depth,
+        q0=q0,
+        q1=q1,
+        random_state=random_state,
+    )
+
+
+def generate_library_of_2q_circuits_for_circuit_op(
+    n_library_circuits: int,
+    circuit_or_op: Union[circuits.AbstractCircuit, ops.Operation],
+    *,
+    max_cycle_depth: int = 100,
+    q0: 'cirq.Qid' = devices.LineQubit(0),
+    q1: 'cirq.Qid' = devices.LineQubit(1),
+    random_state: 'cirq.RANDOM_STATE_OR_SEED_LIKE' = None,
+    tags: Sequence[Any] = (),
+):
+    """Generate a library of two-qubit Circuits.
+
+    For single-qubit gates, this uses PhasedXZGates where the axis-in-XY-plane is one
+    of eight eighth turns and the Z rotation angle is one of eight eighth turns. This
+    provides 8*8=64 total choices, each implementable with one PhasedXZGate. This is
+    appropriate for architectures with microwave single-qubit control.
+
+    Args:
+        n_library_circuits: The number of circuits to generate.
+        circuit_or_op: A circuit on two qubits or a two qubit operation.
+        max_cycle_depth: The maximum cycle_depth in the circuits to generate. If you are using XEB,
+            this must be greater than or equal to the maximum value in `cycle_depths`.
+        q0: The first qubit to use when constructing the circuits.
+        q1: The second qubit to use when constructing the circuits
+        random_state: A random state or seed used to deterministically sample the random circuits.
+        tags: Tags to add to the two qubit operations.
+    """
+    if isinstance(circuit_or_op, ops.Operation):
+        op = circuit_or_op.with_tags(*tags)
+        two_qubit_op_factory = lambda a, b, _: op.with_qubits(a, b)
+    else:
+        cop = circuits.CircuitOperation(circuit_or_op.freeze().with_tags(*tags))
+        two_qubit_op_factory = lambda a, b, _: cop.with_qubits(a, b).mapped_op()
+
+    return _generate_library_of_2q_circuits(
+        n_library_circuits=n_library_circuits,
+        two_qubit_op_factory=two_qubit_op_factory,
+        max_cycle_depth=max_cycle_depth,
+        q0=q0,
+        q1=q1,
+        random_state=random_state,
+    )
 
 
 def _get_active_pairs(graph: nx.Graph, grid_layer: GridInteractionLayer):

cirq-core/cirq/experiments/random_quantum_circuit_generation_test.py

@@ -30,6 +30,7 @@
     get_random_combinations_for_pairs,
     get_random_combinations_for_layer_circuit,
     get_grid_interaction_layer_circuit,
+    generate_library_of_2q_circuits_for_circuit_op,
 )
 
 SINGLE_QUBIT_LAYER = Dict[cirq.GridQubit, Optional[cirq.Gate]]
@@ -86,6 +87,40 @@ def test_generate_library_of_2q_circuits():
             assert m2.operations[0].gate == cirq.CNOT
 
 
+def test_generate_library_of_2q_circuits_for_circuit_op_with_operation():
+    circuits = generate_library_of_2q_circuits_for_circuit_op(
+        n_library_circuits=5,
+        circuit_or_op=cirq.CNOT(cirq.q(0), cirq.q(1)),
+        max_cycle_depth=13,
+        random_state=9,
+    )
+    assert len(circuits) == 5
+    for circuit in circuits:
+        assert len(circuit.all_qubits()) == 2
+        assert sorted(circuit.all_qubits()) == cirq.LineQubit.range(2)
+        for m1, m2 in zip(circuit.moments[::2], circuit.moments[1::2]):
+            assert len(m1.operations) == 2  # single qubit layer
+            assert len(m2.operations) == 1
+            assert m2.operations[0].gate == cirq.CNOT
+
+
+def test_generate_library_of_2q_circuits_for_circuit_op_with_circuit():
+    circuits = generate_library_of_2q_circuits_for_circuit_op(
+        n_library_circuits=5,
+        circuit_or_op=cirq.Circuit(cirq.CNOT(cirq.q(0), cirq.q(1))),
+        max_cycle_depth=13,
+        random_state=9,
+    )
+    assert len(circuits) == 5
+    for circuit in circuits:
+        assert len(circuit.all_qubits()) == 2
+        assert sorted(circuit.all_qubits()) == cirq.LineQubit.range(2)
+        for m1, m2 in zip(circuit.moments[::2], circuit.moments[1::2]):
+            assert len(m1.operations) == 2  # single qubit layer
+            assert len(m2.operations) == 1
+            assert isinstance(m2.operations[0], cirq.CircuitOperation)
+
+
 def test_generate_library_of_2q_circuits_custom_qubits():
     circuits = generate_library_of_2q_circuits(
         n_library_circuits=5,

cirq-core/cirq/experiments/two_qubit_xeb.py

@@ -13,7 +13,7 @@
 # limitations under the License.
 
 """Provides functions for running and analyzing two-qubit XEB experiments."""
-from typing import Sequence, TYPE_CHECKING, Optional, Tuple, Dict, cast, Mapping, Any
+from typing import Sequence, TYPE_CHECKING, Optional, Tuple, Dict, cast, Mapping, Any, Union
 
 from dataclasses import dataclass
 from types import MappingProxyType
@@ -403,6 +403,7 @@ def parallel_xeb_workflow(
     pool: Optional['multiprocessing.pool.Pool'] = None,
     batch_size: int = 9,
     tags: Sequence[Any] = (),
+    entangling_circuit_or_op: Optional[Union['cirq.AbstractCircuit', 'cirq.Operation']] = None,
     **plot_kwargs,
 ) -> Tuple[pd.DataFrame, Sequence['cirq.Circuit'], pd.DataFrame]:
     """A utility method that runs the full XEB workflow.
@@ -424,6 +425,8 @@ def parallel_xeb_workflow(
             environments. The number of (circuit, cycle_depth) tasks to be run in each batch
             is given by this number.
         tags: Tags to add to two qubit operations.
+        entangling_circuit_or_op: Optional operation or circuit for XEB.
+            When provided it overrides `entangling_gate`.
         **plot_kwargs: Arguments to be passed to 'plt.Axes.plot'.
 
     Returns:
@@ -447,13 +450,22 @@ def parallel_xeb_workflow(
         ax.set_title('device layout')
         ax.plot(**plot_kwargs)
 
-    circuit_library = rqcg.generate_library_of_2q_circuits(
-        n_library_circuits=n_circuits,
-        two_qubit_gate=entangling_gate,
-        random_state=rs,
-        max_cycle_depth=max(cycle_depths),
-        tags=tags,
-    )
+    if entangling_circuit_or_op is not None:
+        circuit_library = rqcg.generate_library_of_2q_circuits_for_circuit_op(
+            n_library_circuits=n_circuits,
+            circuit_or_op=entangling_circuit_or_op,
+            random_state=rs,
+            max_cycle_depth=max(cycle_depths),
+            tags=tags,
+        )
+    else:
+        circuit_library = rqcg.generate_library_of_2q_circuits(
+            n_library_circuits=n_circuits,
+            two_qubit_gate=entangling_gate,
+            random_state=rs,
+            max_cycle_depth=max(cycle_depths),
+            tags=tags,
+        )
 
     combs_by_layer = rqcg.get_random_combinations_for_device(
         n_library_circuits=len(circuit_library),
@@ -492,6 +504,7 @@ def parallel_two_qubit_xeb(
     pairs: Optional[Sequence[tuple['cirq.GridQubit', 'cirq.GridQubit']]] = None,
     batch_size: int = 9,
     tags: Sequence[Any] = (),
+    entangling_circuit_or_op: Optional[Union['cirq.AbstractCircuit', 'cirq.Operation']] = None,
     **plot_kwargs,
 ) -> TwoQubitXEBResult:
     """A convenience method that runs the full XEB workflow.
@@ -512,6 +525,8 @@ def parallel_two_qubit_xeb(
             environments. The number of (circuit, cycle_depth) tasks to be run in each batch
             is given by this number.
         tags: Tags to add to two qubit operations.
+        entangling_circuit_or_op: Optional operation or circuit for XEB.
+            When provided it overrides `entangling_gate`.
         **plot_kwargs: Arguments to be passed to 'plt.Axes.plot'.
     Returns:
         A TwoQubitXEBResult object representing the results of the experiment.
@@ -531,6 +546,7 @@ def parallel_two_qubit_xeb(
         ax=ax,
         batch_size=batch_size,
         tags=tags,
+        entangling_circuit_or_op=entangling_circuit_or_op,
         **plot_kwargs,
     )
     return TwoQubitXEBResult(fit_exponential_decays(fids))
@@ -551,6 +567,7 @@ def run_rb_and_xeb(
     pairs: Optional[Sequence[tuple['cirq.GridQubit', 'cirq.GridQubit']]] = None,
     batch_size: int = 9,
     tags: Sequence[Any] = (),
+    entangling_circuit_or_op: Optional[Union['cirq.AbstractCircuit', 'cirq.Operation']] = None,
 ) -> InferredXEBResult:
     """A convenience method that runs both RB and XEB workflows.
 
@@ -569,6 +586,8 @@ def run_rb_and_xeb(
             environments. The number of (circuit, cycle_depth) tasks to be run in each batch
             is given by this number.
         tags: Tags to add to two qubit operations.
+        entangling_circuit_or_op: Optional operation or circuit for XEB.
+            When provided it overrides `entangling_gate`.
 
     Returns:
         An InferredXEBResult object representing the results of the experiment.
@@ -599,6 +618,7 @@ def run_rb_and_xeb(
         random_state=random_state,
         batch_size=batch_size,
         tags=tags,
+        entangling_circuit_or_op=entangling_circuit_or_op,
     )
 
     return InferredXEBResult(rb, xeb)

cirq-core/cirq/experiments/two_qubit_xeb_test.py

@@ -310,6 +310,57 @@ def test_run_rb_and_xeb(
     )
 
 
+@pytest.mark.parametrize(
+    'sampler,qubits,pairs',
+    [
+        (
+            cirq.DensityMatrixSimulator(
+                seed=0, noise=cirq.ConstantQubitNoiseModel(cirq.amplitude_damp(0.1))
+            ),
+            cirq.GridQubit.rect(3, 2, 4, 3),
+            None,
+        ),
+        (
+            cirq.DensityMatrixSimulator(
+                seed=0, noise=cirq.ConstantQubitNoiseModel(cirq.amplitude_damp(0.1))
+            ),
+            None,
+            [
+                (cirq.GridQubit(0, 0), cirq.GridQubit(0, 1)),
+                (cirq.GridQubit(0, 0), cirq.GridQubit(1, 0)),
+            ],
+        ),
+        (
+            DensityMatrixSimulatorWithProcessor(
+                seed=0, noise=cirq.ConstantQubitNoiseModel(cirq.amplitude_damp(0.1))
+            ),
+            None,
+            None,
+        ),
+    ],
+)
+def test_run_rb_and_xeb_with_circuit(
+    sampler: cirq.Sampler,
+    qubits: Optional[Sequence[cirq.GridQubit]],
+    pairs: Optional[Sequence[tuple[cirq.GridQubit, cirq.GridQubit]]],
+):
+    res = cirq.experiments.run_rb_and_xeb(
+        sampler=sampler,
+        qubits=qubits,
+        pairs=pairs,
+        repetitions=100,
+        num_clifford_range=tuple(np.arange(3, 10, 1)),
+        xeb_combinations=1,
+        num_circuits=1,
+        depths_xeb=(3, 4, 5),
+        random_state=0,
+        entangling_circuit_or_op=cirq.Circuit(cirq.CZ(cirq.q(0), cirq.q(1))),
+    )
+    np.testing.assert_allclose(
+        [res.xeb_result.xeb_error(*pair) for pair in res.all_qubit_pairs], 0.1, atol=1e-1
+    )
+
+
 def test_run_rb_and_xeb_without_processor_fails():
     sampler = (
         cirq.DensityMatrixSimulator(

cirq-core/cirq/experiments/xeb_sampling.py

@@ -34,7 +34,7 @@
 import tqdm
 
 from cirq import ops, devices, value, protocols
-from cirq.circuits import Circuit, Moment
+from cirq.circuits import Circuit, Moment, CircuitOperation
 from cirq.experiments.random_quantum_circuit_generation import CircuitLibraryCombination
 
 if TYPE_CHECKING:
@@ -172,6 +172,12 @@ class _ZippedCircuit:
     combination_i: int
 
 
+def _map_circuit(circuit):
+    """Calls .mapped_op on all CircuitOperations within the circuit."""
+    op_fn = lambda op: op.mapped_op() if isinstance(op, CircuitOperation) else op
+    return Circuit.from_moments(*[[op_fn(op) for op in m] for m in circuit])
+
+
 def _get_combinations_by_layer_for_isolated_xeb(
     circuits: Sequence['cirq.Circuit'],
 ) -> Tuple[List[CircuitLibraryCombination], List['cirq.Circuit']]:
@@ -184,7 +190,11 @@ def _get_combinations_by_layer_for_isolated_xeb(
     """
     q0, q1 = _verify_and_get_two_qubits_from_circuits(circuits)
     circuits = [
-        circuit.transform_qubits(lambda q: {q0: devices.LineQubit(0), q1: devices.LineQubit(1)}[q])
+        _map_circuit(
+            circuit.transform_qubits(
+                lambda q: {q0: devices.LineQubit(0), q1: devices.LineQubit(1)}[q]
+            )
+        )
         for circuit in circuits
     ]
     return [
@@ -215,7 +225,7 @@ def _zip_circuits(
         for combination_i, combination in enumerate(layer_combinations.combinations):
             wide_circuit = Circuit.zip(
                 *(
-                    circuits[i].transform_qubits(lambda q: pair[q.x])
+                    _map_circuit(circuits[i].transform_qubits(lambda q: pair[q.x]))
                     for i, pair in zip(combination, layer_combinations.pairs)
                 )
             )