Pennylane-qiskit

Improvements

* Removed a validation check for `qml.QubitUnitary` that existed in the device and
adjusted a related test case.
[(144)](https://github.com/PennyLaneAI/pennylane-qiskit/pull/144)

Contributors

This release contains contributions from (in alphabetical order):

Christina Lee, Antal Száva

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New features since last release

* Added support for the new `qml.Projector` observable in
PennyLane v0.16 to the Qiskit devices.
[(137)](https://github.com/PennyLaneAI/pennylane-qiskit/pull/137)

Breaking changes

* Deprecated Python 3.6.
[(140)](https://github.com/PennyLaneAI/pennylane-qiskit/pull/140)

Improvements

* The plugin can now load Qiskit circuits with more complicated `ParameterExpression` variables.
[(139)](https://github.com/PennyLaneAI/pennylane-qiskit/pull/139)

Contributors

This release contains contributions from (in alphabetical order):

Christina Lee, Vincent Wong

Breaking changes

* For compatibility with PennyLane v0.15, the `analytic` keyword argument
has been removed from all devices. Statistics can still be computed analytically
by setting `shots=None`.
[(130)](https://github.com/XanaduAI/pennylane-qiskit/pull/130)

Improvements

* PennyLane-Qiskit has been upgraded to work with Qiskit version 0.25.
[(132)](https://github.com/XanaduAI/pennylane-qiskit/pull/132)

Contributors

This release contains contributions from (in alphabetical order):

Christina Lee, Olivia Di Matteo, Josh Izaac, Antal Száva

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Bug fixes

* With the release of Qiskit 0.23.3 gate parameters cannot be arrays. The device now converts arrays to lists.
[(126)](https://github.com/PennyLaneAI/pennylane-qiskit/pull/126)

* When parsing the IBMQ token and the IBMQ URL, the values passed as keywords take precedence over environment variables.
[(121)](https://github.com/PennyLaneAI/pennylane-qiskit/pull/121)

* When loading Qiskit circuits to PennyLane templates using `load` in `converter.py`, parameters with `requires_grad=False` are bound to the circuit. The old version bound objects that were not PennyLane `Variable`'s, but that object class is now deprecated.
[(127)](https://github.com/PennyLaneAI/pennylane-qiskit/pull/127)

Contributors

This release contains contributions from (in alphabetical order):

Christina Lee, Antal Szava

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Improvements

* The provided devices are now compatible with Qiskit 0.23.1.
[(116)](https://github.com/PennyLaneAI/pennylane-qiskit/pull/116)

Bug fixes

* The Aer devices store the noise models correctly.
[(114)](https://github.com/PennyLaneAI/pennylane-qiskit/pull/114)

Contributors

This release contains contributions from (in alphabetical order):

Olivia Di Matteo, Josh Izaac, Antal Száva

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Improvements

* Qiskit devices are now allowed to pass transpilation options.
[(108)](https://github.com/PennyLaneAI/pennylane-qiskit/pull/108)

* The provided devices are now compatible with Qiskit 0.23.
[(112)](https://github.com/PennyLaneAI/pennylane-qiskit/pull/112)

Bug fixes

* Removes PySCF from the plugin `setup.py` and `requirements.txt`.
[(103)](https://github.com/PennyLaneAI/pennylane-qiskit/pull/103)
[(104)](https://github.com/PennyLaneAI/pennylane-qiskit/pull/104)

* Fixed a bug related to extracting differentiable parameters for the Qiskit
converter and PennyLane array indexing.
[(106)](https://github.com/PennyLaneAI/pennylane-qiskit/pull/106)

Contributors

This release contains contributions from (in alphabetical order):

Josh Izaac, Nathan Killoran, Sagar Pahwa, Antal Száva

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