Jake Lishman

For the current definition of the V2 primitives, the only Qiskit-defined class other than `SparsePauliOp` that can be given as an observable is `Pauli`, which we could add `apply_layout` to....

Since #12066 merged, we've got `apply_layout` on everything that's a possible input to the `EstimatorV2` primitive, I think, which should bridge the gap before we know what a complete solution...

This is because `control` by default, for historical reasons, performs an eager synthesis of the control operation, so the scaling is fairly naturally super-linear (for arbitrary controlled gates). The solution...

Just as an immediate copy-pastable example of the above: ```python from qiskit import QuantumCircuit N = 100 sub_qc = QuantumCircuit(1) sub_qc.x(0) out = QuantumCircuit(N) out.compose(sub_qc,range(sub_qc.num_qubits), inplace=True) for kk in range(N-1):...

Fwiw, slightly better form for this would be to do: ```python from qiskit import QuantumCircuit N = 100 sub_qc = QuantumCircuit(1) sub_qc.x(0) sub = sub_qc.to_gate() out = QuantumCircuit(N) out.append(sub, range(sub.num_qubits))...

It's not on by default because that would have been a major breaking API change, and we're not confident that it's as well supported through the entire stack as the...

Please could you: - try to reproduce this failure on a more recent version of Qiskit? There have been quite a few bugfix releases since Qiskit 0.44.1. - try to...

Thanks for the report. We have logic that does this in the OpenQASM 2 exporter, so I think we must have forgotten to port over similar behaviour to the OpenQASM...

Please can you clarify the Qiskit version you're using, but also: your title mentions `generate_preset_pass_manager` but the code block doesn't use it. I imagine the same behaviour is between both,...

Rebased over #11820.