Qiskit 2 support

[MoritzWillmann]

This pull request updates the minimum supported Python version to 3.10 and modernizes Qiskit usage throughout the codebase and documentation. It also removes support for legacy Qiskit and Python 3.9 in CI workflows, updates dependencies, and improves example notebooks to use the latest Qiskit primitives.

Python and dependency updates:

• Increased the minimum required Python version from 3.9 to 3.10 in documentation, README, and CI workflows, and removed Python 3.9 from test matrices. [1] [2] [3] [4] [5] [6] [7]
• Updated dependency requirements: increased minimum versions for dill, mapomatic, numpy, qiskit, and related packages in docs/install/install.rst.
• Updated README and documentation to reflect new minimum Python version and dependency changes. [1] [2]

CI workflow and test improvements:

• Removed all Python 3.9 jobs and related autoray installation steps from GitHub Actions workflows. [1] [2] [3] [4] [5]
• Updated Qiskit test jobs to use Qiskit 1.x and Python 3.10–3.13, simplifying installation commands and removing explicit old-version pins. [1] [2] [3]

Example and documentation modernization:

• Updated Qiskit code examples in the notebook example_executor_qiskit.ipynb to use the new V2 primitives (StatevectorSampler, StatevectorEstimator, BackendSamplerV2, BackendEstimatorV2) and removed deprecated V1 classes and warnings. [1] [2] [3] [4]
• Updated usage examples in the user guide to use correct Qiskit imports (replacing TwoLocal with n_local).

General cleanup:

• Adjusted kernel display name in the example notebook for consistency.
• Updated minor output and execution count changes in the example notebook for clarity. [1] [2] [3] [4] [5] [6] [7]

These updates ensure compatibility with the latest Qiskit versions and improve maintainability by dropping support for outdated Python and Qiskit versions.

[David-Kreplin]

Maybe a good chance to get rid of the qiskit_algorithms, which is only needed for fidelity quantum circuits.
We have fast implementation for that for PennyLane and Qulacs, but not for Qiskit.

[David-Kreplin]

Mapomatic causes problems with Qiskit 2.0 since it also checks for BackendV1 that is depricated in Qiskit 2.0.
I don't know, if they ever gonna update the Mapomatic Package, maybe we have to create a fix and hope someone will merge it and relase a new Mapomatic version.

[MoritzWillmann]

Mapomatic causes problems with Qiskit 2.0 since it also checks for BackendV1 that is depricated in Qiskit 2.0. I don't know, if they ever gonna update the Mapomatic Package, maybe we have to create a fix and hope someone will merge it and relase a new Mapomatic version.

Should be fixed now (qiskit-community/mapomatic#77)

[github-actions]

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[github-actions]

This PR is stale because it has been open 30 days with no activity. Remove stale label or comment or this will be closed in 1 year.

[Copilot]

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Copilot reviewed 33 out of 35 changed files in this pull request and generated 6 comments.

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[Copilot]

Pull request overview

Copilot reviewed 33 out of 35 changed files in this pull request and generated 5 comments.

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