Fix issues in IBMBackend

This commit fixes some issues in the IBMBackend class, specifically
around the parsing of the configuration data and gaps in the migration.
The two issues are first a unit conversion issue between the BackendV2
abstract interface expecations. BackendV2 and Target are explicitly in
seconds for all duration fields and the api payloads are in nanoseconds.
The second issue is that for BackendV1 the delay operation is a built-in
directive for all backends but in BackendV2 it must be defined in the
target if the backend supports it. To ensure that uses can still compile
to an IBM backend target the delay instruction is added to the target to
indicate it's a valid operation on all qubits.

qiskit_ibm_provider/ibm_backend.py

@@ -309,7 +309,7 @@ def dtm(self) -> float:
         Returns:
             dtm: The output signal timestep in seconds.
         """
-        return self._configuration.dtm
+        return self._configuration.dtm * 1e-9
 
     @property
     def max_circuits(self) -> int:

qiskit_ibm_provider/utils/backend_converter.py

@@ -19,6 +19,7 @@
 from qiskit.circuit.library.standard_gates import IGate, SXGate, XGate, CXGate, RZGate
 from qiskit.circuit.parameter import Parameter
 from qiskit.circuit.gate import Gate
+from qiskit.circuit.delay import Delay
 from qiskit.circuit.measure import Measure
 from qiskit.circuit.reset import Reset
 from qiskit.providers.models import (
@@ -107,7 +108,7 @@ def convert_to_target(
         target.add_instruction(Measure())
     # parse global configuration properties
     if hasattr(configuration, "dt"):
-        target.dt = configuration.dt
+        target.dt = configuration.dt * 1e-9
     if hasattr(configuration, "timing_constraints"):
         target.granularity = configuration.timing_constraints.get("granularity")
         target.min_length = configuration.timing_constraints.get("min_length")
@@ -131,6 +132,9 @@ def convert_to_target(
                             target[inst][(qubit,)].calibration = sched
                     else:
                         target[inst][qarg].calibration = sched
+    target.add_instruction(
+        Delay(Parameter("t")), {(bit,): None for bit in range(target.num_qubits)}
+    )
     return target