Migrate tutorials and a how-to guide to v2 primitives

[garrison]

This builds on #513 and follows https://docs.quantum.ibm.com/api/migration-guides/local-simulators.

I've added this to the 0.7.0 milestone, but it need not block the release because this portion can be moved to the 0.7.1 milestone and backported once it is ready.

• Fixes #511.
• Fixes #509.
• Fixes #505.
• Fixes #535.
• Progress toward #477.

Remaining action items

• [x] use sampler with fake backend instead of aer backend
• [x] update other tutorials, and any how-tos that need it
• [x] investigate whether the qiskit-ibm-runtime warning about using session in local mode is truly necessary: https://github.com/Qiskit/qiskit-ibm-runtime/issues/1626

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Totals
Change from base Build 8726584501:	0.0%
Covered Lines:	3452
Relevant Lines:	3617

---

💛 - Coveralls

[garrison]

With the change to a fake backend, the first tutorial notebook now takes over 15 minutes to execute on my laptop. :sob:

EDIT: I changed to a 5-qubit fake backend, and now it runs within a reasonable time.

[garrison]

With this change, the tutorials are a bit slower, but I think it is acceptable. It's just so nice to use Qiskit Runtime with fake backends everywhere. If a user wants to use a real backend, they need only modify the backend.

Before

============================= slowest 10 durations =============================
30.34s call     docs/circuit_cutting/tutorials/02_gate_cutting_to_reduce_circuit_depth.ipynb::
7.10s call     docs/circuit_cutting/tutorials/01_gate_cutting_to_reduce_circuit_width.ipynb::
7.03s call     docs/circuit_cutting/cutqc/tutorials/tutorial_1_automatic_cut_finding.ipynb::
6.43s call     docs/circuit_cutting/tutorials/03_wire_cutting_via_move_instruction.ipynb::
6.23s call     docs/circuit_cutting/cutqc/tutorials/tutorial_2_manual_cutting.ipynb::
5.32s call     docs/circuit_cutting/how-tos/how_to_specify_cut_wires.ipynb::
3.70s call     docs/circuit_cutting/tutorials/04_automatic_cut_finding.ipynb::
3.57s call     docs/circuit_cutting/how-tos/how_to_generate_exact_sampling_coefficients.ipynb::
1.46s call     docs/circuit_cutting/how-tos/how_to_generate_exact_quasi_dists_from_sampler.ipynb::

After

============================= slowest 10 durations =============================
40.44s call     docs/circuit_cutting/tutorials/02_gate_cutting_to_reduce_circuit_depth.ipynb::
17.30s call     docs/circuit_cutting/tutorials/01_gate_cutting_to_reduce_circuit_width.ipynb::
16.22s call     docs/circuit_cutting/tutorials/03_wire_cutting_via_move_instruction.ipynb::
7.09s call     docs/circuit_cutting/cutqc/tutorials/tutorial_2_manual_cutting.ipynb::
7.01s call     docs/circuit_cutting/cutqc/tutorials/tutorial_1_automatic_cut_finding.ipynb::
6.93s call     docs/circuit_cutting/how-tos/how_to_specify_cut_wires.ipynb::
3.94s call     docs/circuit_cutting/tutorials/04_automatic_cut_finding.ipynb::
2.91s call     docs/circuit_cutting/how-tos/how_to_generate_exact_sampling_coefficients.ipynb::
1.34s call     docs/circuit_cutting/how-tos/how_to_generate_exact_quasi_dists_from_sampler.ipynb::

[caleb-johnson]

With this change, the tutorials are a bit slower, but I think it is acceptable. It's just so nice to use Qiskit Runtime with fake backends everywhere. If a user wants to use a real backend, they need only modify the backend.

Before

============================= slowest 10 durations =============================
30.34s call     docs/circuit_cutting/tutorials/02_gate_cutting_to_reduce_circuit_depth.ipynb::
7.10s call     docs/circuit_cutting/tutorials/01_gate_cutting_to_reduce_circuit_width.ipynb::
7.03s call     docs/circuit_cutting/cutqc/tutorials/tutorial_1_automatic_cut_finding.ipynb::
6.43s call     docs/circuit_cutting/tutorials/03_wire_cutting_via_move_instruction.ipynb::
6.23s call     docs/circuit_cutting/cutqc/tutorials/tutorial_2_manual_cutting.ipynb::
5.32s call     docs/circuit_cutting/how-tos/how_to_specify_cut_wires.ipynb::
3.70s call     docs/circuit_cutting/tutorials/04_automatic_cut_finding.ipynb::
3.57s call     docs/circuit_cutting/how-tos/how_to_generate_exact_sampling_coefficients.ipynb::
1.46s call     docs/circuit_cutting/how-tos/how_to_generate_exact_quasi_dists_from_sampler.ipynb::

After

============================= slowest 10 durations =============================
40.44s call     docs/circuit_cutting/tutorials/02_gate_cutting_to_reduce_circuit_depth.ipynb::
17.30s call     docs/circuit_cutting/tutorials/01_gate_cutting_to_reduce_circuit_width.ipynb::
16.22s call     docs/circuit_cutting/tutorials/03_wire_cutting_via_move_instruction.ipynb::
7.09s call     docs/circuit_cutting/cutqc/tutorials/tutorial_2_manual_cutting.ipynb::
7.01s call     docs/circuit_cutting/cutqc/tutorials/tutorial_1_automatic_cut_finding.ipynb::
6.93s call     docs/circuit_cutting/how-tos/how_to_specify_cut_wires.ipynb::
3.94s call     docs/circuit_cutting/tutorials/04_automatic_cut_finding.ipynb::
2.91s call     docs/circuit_cutting/how-tos/how_to_generate_exact_sampling_coefficients.ipynb::
1.34s call     docs/circuit_cutting/how-tos/how_to_generate_exact_quasi_dists_from_sampler.ipynb::

Agree with this. I really like the FakeBackends for demos for that same reason

[caleb-johnson]

With the change to a fake backend, the first tutorial notebook now takes over 15 minutes to execute on my laptop. 😭

EDIT: I changed to a 5-qubit fake backend, and now it runs within a reasonable time.

I'm seeing the same behavior on my end. I wonder if we should run some quick numbers and report this up. Maybe this is expected, but it seems like a massive slowdown over V1

EDIT: Only about 3 minutes on my end, but still much slower

[garrison]

I wonder if we should run some quick numbers and report this up.

It is all a bit opaque to me, but here is what I suspect is happening: When we use a 5-qubit fake backend, the code simulates all 5 qubits, even when only 2 or 4 are in use, which can be a couple times slower. Plus, there might be some additional slowdown due to applying the noise model from the chosen fake backend. So in that sense it may not be surprising that it is slower to use a fake backend than a noiseless AerSimulator. Also, my hunch is consistent with the massive slowdown I saw when using the same code with FakeTorino (133 qubits). On that many qubits, it's essentially forced to use the MPS simulator if it doesn't know just to ignore the unused qubits (and perhaps one cannot model the noise "correctly" without including unused qubits in the simulation -- I don't know).