Fixes for backends with ECRGate employing qiskit-community#1288

qiskit_experiments/library/randomized_benchmarking/clifford_utils.py

@@ -365,7 +365,11 @@ def inverse_1q(num: Integral) -> Integral:
 
 
 def num_from_1q_circuit(qc: QuantumCircuit) -> Integral:
-    """Convert a given 1-qubit Clifford circuit to the corresponding integer."""
+    """Convert a given 1-qubit Clifford circuit to the corresponding integer.
+
+    Note: The circuit must consist of gates in :const:`_CLIFF_SINGLE_GATE_MAP_1Q`,
+    RZGate, Delay and Barrier.
+    """
     num = 0
     for inst in qc:
         rhs = _num_from_1q_gate(op=inst.operation)
@@ -376,7 +380,7 @@ def num_from_1q_circuit(qc: QuantumCircuit) -> Integral:
 def _num_from_1q_gate(op: Instruction) -> int:
     """
     Convert a given 1-qubit clifford operation to the corresponding integer.
-    Note that supported operations are limited to ones in :const:`CLIFF_SINGLE_GATE_MAP_1Q` or Rz gate.
+    Note that supported operations are limited to ones in :const:`_CLIFF_SINGLE_GATE_MAP_1Q` or Rz gate.
 
     Args:
         op: operation to be converted.
@@ -435,7 +439,11 @@ def inverse_2q(num: Integral) -> Integral:
 
 
 def num_from_2q_circuit(qc: QuantumCircuit) -> Integral:
-    """Convert a given 2-qubit Clifford circuit to the corresponding integer."""
+    """Convert a given 2-qubit Clifford circuit to the corresponding integer.
+
+    Note: The circuit must consist of gates in :const:`_CLIFF_SINGLE_GATE_MAP_2Q`,
+    RZGate, Delay and Barrier.
+    """
     lhs = 0
     for rhs in _clifford_2q_nums_from_2q_circuit(qc):
         lhs = _CLIFFORD_COMPOSE_2Q_DENSE[lhs, _clifford_num_to_dense_index[rhs]]
@@ -447,7 +455,7 @@ def _num_from_2q_gate(
 ) -> int:
     """
     Convert a given 1-qubit clifford operation to the corresponding integer.
-    Note that supported operations are limited to ones in `CLIFF_SINGLE_GATE_MAP_2Q` or Rz gate.
+    Note that supported operations are limited to ones in `_CLIFF_SINGLE_GATE_MAP_2Q` or Rz gate.
 
     Args:
         op: operation of instruction to be converted.

qiskit_experiments/library/randomized_benchmarking/layer_fidelity.py

@@ -12,6 +12,7 @@
 """
 Layer Fidelity RB Experiment class.
 """
+import functools
 import logging
 from collections import defaultdict
 from typing import Union, Iterable, Optional, List, Sequence, Tuple
@@ -25,19 +26,21 @@
 from qiskit.exceptions import QiskitError
 from qiskit.providers import BackendV2Converter
 from qiskit.providers.backend import Backend, BackendV1, BackendV2
+from qiskit.quantum_info import Clifford
 from qiskit.pulse.instruction_schedule_map import CalibrationPublisher
 
 from qiskit_experiments.framework import BaseExperiment, Options
 from qiskit_experiments.framework.restless_mixin import RestlessMixin
 
 from .clifford_utils import (
     CliffordUtils,
+    DEFAULT_SYNTHESIS_METHOD,
     compose_1q,
     compose_2q,
     inverse_1q,
     inverse_2q,
+    num_from_2q_circuit,
     _product_1q_nums,
-    _num_from_2q_gate,
     _clifford_1q_int_to_instruction,
     _clifford_2q_int_to_instruction,
     _decompose_clifford_ops,
@@ -150,6 +153,8 @@ def _default_experiment_options(cls) -> Options:
                 :meth:`circuits` is called.
             two_qubit_gate (str): Two-qubit gate name (e.g. "cx", "cz", "ecr") of which the two qubit layers consist.
             one_qubit_basis_gates (Tuple[str]): One-qubit gates to use for implementing 1q Clifford operations.
+            clifford_synthesis_method (str): The name of the Clifford synthesis plugin to use
+                for building circuits of RB sequences.
         """
         options = super()._default_experiment_options()
         options.update_options(
@@ -158,7 +163,8 @@ def _default_experiment_options(cls) -> Options:
             seed=None,
             two_qubit_layers=None,
             two_qubit_gate=None,
-            one_qubit_basis_gates=tuple(),
+            one_qubit_basis_gates=(),
+            clifford_synthesis_method=DEFAULT_SYNTHESIS_METHOD,
         )
         return options
 
@@ -215,10 +221,20 @@ def circuits(self) -> List[QuantumCircuit]:
         """
         opts = self.experiment_options
         rng = default_rng(seed=opts.seed)
-        basis_gates = (opts.two_qubit_gate,) + opts.one_qubit_basis_gates
         GATE2Q = GATE_NAME_MAP[opts.two_qubit_gate]
-        GATE2Q_CLIFF = _num_from_2q_gate(GATE2Q)
+        GATE2Q_CLIFF = num_from_2q_circuit(Clifford(GATE2Q).to_circuit())
         residal_qubits_by_layer = [self.__residual_qubits(layer) for layer in opts.two_qubit_layers]
+        _to_gate_1q = functools.partial(
+            _clifford_1q_int_to_instruction,
+            basis_gates=opts.one_qubit_basis_gates,
+            synthesis_method=opts.clifford_synthesis_method,
+        )
+        _to_gate_2q = functools.partial(
+            _clifford_2q_int_to_instruction,
+            basis_gates=(opts.two_qubit_gate,) + opts.one_qubit_basis_gates,
+            coupling_tuple=((0, 1),),
+            synthesis_method=opts.clifford_synthesis_method,
+        )
         # Circuit generation
         circuits = []
         num_qubits = max(self.physical_qubits) + 1
@@ -245,25 +261,15 @@ def circuits(self) -> List[QuantumCircuit]:
                             samples = rng.integers(NUM_1Q_CLIFFORD, size=2)
                             cliffs_2q[j] = compose_2q(cliffs_2q[j], _product_1q_nums(*samples))
                             for sample, q in zip(samples, qpair):
-                                circ._append(
-                                    _clifford_1q_int_to_instruction(
-                                        sample, opts.one_qubit_basis_gates
-                                    ),
-                                    (circ.qubits[q],),
-                                    tuple(),
-                                )
+                                circ._append(_to_gate_1q(sample), (circ.qubits[q],), ())
                         for k, q in enumerate(one_qubits):
                             sample = rng.integers(NUM_1Q_CLIFFORD)
                             cliffs_1q[k] = compose_1q(cliffs_1q[k], sample)
-                            circ._append(
-                                _clifford_1q_int_to_instruction(sample, opts.one_qubit_basis_gates),
-                                (circ.qubits[q],),
-                                tuple(),
-                            )
+                            circ._append(_to_gate_1q(sample), (circ.qubits[q],), ())
                         circ.barrier(self.physical_qubits)
                         # add two qubit gates
                         for j, qpair in enumerate(two_qubit_layer):
-                            circ._append(GATE2Q, tuple(circ.qubits[q] for q in qpair), tuple())
+                            circ._append(GATE2Q, tuple(circ.qubits[q] for q in qpair), ())
                             cliffs_2q[j] = compose_2q(cliffs_2q[j], GATE2Q_CLIFF)
                             # TODO: add dd if necessary
                         for k, q in enumerate(one_qubits):
@@ -273,18 +279,10 @@ def circuits(self) -> List[QuantumCircuit]:
                     # add the last inverse
                     for j, qpair in enumerate(two_qubit_layer):
                         inv = inverse_2q(cliffs_2q[j])
-                        circ._append(
-                            _clifford_2q_int_to_instruction(inv, basis_gates),
-                            tuple(circ.qubits[q] for q in qpair),
-                            tuple(),
-                        )
+                        circ._append(_to_gate_2q(inv), tuple(circ.qubits[q] for q in qpair), ())
                     for k, q in enumerate(one_qubits):
                         inv = inverse_1q(cliffs_1q[k])
-                        circ._append(
-                            _clifford_1q_int_to_instruction(inv, opts.one_qubit_basis_gates),
-                            (circ.qubits[q],),
-                            tuple(),
-                        )
+                        circ._append(_to_gate_1q(inv), (circ.qubits[q],), ())
                     # add the measurements
                     circ.barrier(self.physical_qubits)
                     for qubits, clbits in zip(composite_qubits, composite_clbits):

qiskit_experiments/library/randomized_benchmarking/layer_fidelity_analysis.py

@@ -232,15 +232,15 @@ def _run_analysis(
             quality=quality_lf,
             extra={},
         )
-        eplg = 1 - (lf ** (1/self.num_2q_gates))
+        eplg = 1 - (lf ** (1 / self.num_2q_gates))
         eplg_result = AnalysisResultData(
             name="EPLG",
             value=eplg,
             chisq=None,
             quality=quality_lf,
             extra={},
         )
-        
+
         # Return combined results
         analysis_results = [lf_result, eplg_result] + analysis_results
         return analysis_results, figures

test/library/randomized_benchmarking/test_layer_fidelity.py

@@ -54,17 +54,15 @@ def test_invalid_two_qubit_layers(self):
         # not disjoit
         with self.assertRaises(QiskitError):
             LayerFidelity(
-                physical_qubits=(0, 1, 2, 3),
-                two_qubit_layers=[[(0, 1), (1, 2)]],
-                **valid_kwargs
+                physical_qubits=(0, 1, 2, 3), two_qubit_layers=[[(0, 1), (1, 2)]], **valid_kwargs
             )
         # no 2q-gate on the qubits (FakeManilaV2 has no cx gate on (0, 3))
         with self.assertRaises(QiskitError):
             LayerFidelity(
                 physical_qubits=(0, 1, 2, 3),
                 two_qubit_layers=[[(0, 3)]],
                 backend=FakeManilaV2(),
-                **valid_kwargs
+                **valid_kwargs,
             )
 
     def test_roundtrip_serializable(self):