Pennylane-qiskit

New features since last release

Improvements 🛠

Breaking changes 💔

Deprecations 👋

Documentation 📝

Bug fixes 🐛

Contributors ✍️

This release contains contributions from (in alphabetical order):

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Improvements 🛠

* The UI for passing parameters to a `qfunc` generated when loading a Qiskit `QuantumCircuit`
into PennyLane is updated to allow passing parameters as args or kwargs, rather than as
a dictionary. The old dictionary UI continues to be supported.
[(406)](https://github.com/PennyLaneAI/pennylane-qiskit/pull/406)
[(428)](https://github.com/PennyLaneAI/pennylane-qiskit/pull/428)

* Measurement operations are now added to the PennyLane template when a `QuantumCircuit`
is converted using `load`. Additionally, one can override any existing terminal
measurements by providing a list of PennyLane
`measurements <https://docs.pennylane.ai/en/stable/introduction/measurements.html>`_ themselves.
[(405)](https://github.com/PennyLaneAI/pennylane-qiskit/pull/405)
[(466)](https://github.com/PennyLaneAI/pennylane-qiskit/pull/466)
[(467)](https://github.com/PennyLaneAI/pennylane-qiskit/pull/467)

* Added the support for converting conditional operations based on mid-circuit measurements and
two of the `ControlFlowOp` operations - `IfElseOp` and `SwitchCaseOp` when converting
a `QuantumCircuit` using `load`.
[(417)](https://github.com/PennyLaneAI/pennylane-qiskit/pull/417)
[(465)](https://github.com/PennyLaneAI/pennylane-qiskit/pull/465)

* Qiskit's classical `Expr` conditionals can also be used with the supported
`ControlFlowOp` operations.
[(432)](https://github.com/PennyLaneAI/pennylane-qiskit/pull/432)

* Added conversion support for more Qiskit gates to native PennyLane operations -
`Barrier`, `CYGate`, `CHGate`, `CPhase`, `CCZGate`, `ECRGate`, and `GlobalPhaseGate`.
[(449)](https://github.com/PennyLaneAI/pennylane-qiskit/pull/449)

* Added the ability to convert a Qiskit `SparsePauliOp` instance into a PennyLane `Operator`.
[(401)](https://github.com/PennyLaneAI/pennylane-qiskit/pull/401)
[(453)](https://github.com/PennyLaneAI/pennylane-qiskit/pull/453)

* Added a `pennylane.io` entry point for converting Qiskit operators.
[(453)](https://github.com/PennyLaneAI/pennylane-qiskit/pull/453)

* Unused parameters are now ignored when a `QuantumCircuit` is converted using `load`.
[(454)](https://github.com/PennyLaneAI/pennylane-qiskit/pull/454)

Bug fixes 🐛

* `QiskitDevice.batch_execute()` now gracefully handles empty lists of circuits.
[(459)](https://github.com/PennyLaneAI/pennylane-qiskit/pull/459)

* It is now possible to compute the gradient of a circuit with `ParameterVector` elements.
[(458)](https://github.com/PennyLaneAI/pennylane-qiskit/pull/458)

Contributors ✍️

This release contains contributions from (in alphabetical order):

Mikhail Andrenkov
Utkarsh Azad
Lillian Frederiksen

---

Bug fixes 🐛

* The kwargs `job_tags` and `session_id` are passed to the correct arguments in the
`circuit_runner` device so that they will be used in the Qiskit backend; these
were previously ignored.
[(358)](https://github.com/PennyLaneAI/pennylane-qiskit/pull/358)

* The `generate_samples` method for the `IBMQSamplerDevice` is updated to get counts
from the nearest probability distribution rather than the quasi-distribution (which
may contain negative probabilities and therefore raise errors).
[(357)](https://github.com/PennyLaneAI/pennylane-qiskit/pull/357)

* The `generate_samples` method for the `IBMQSamplerDevice` now avoids raising an
indexing error when some states are not populated, and labels states according to
the Pennylane convention instead of Qiskit convention.
[(357)](https://github.com/PennyLaneAI/pennylane-qiskit/pull/357)


Contributors ✍️

This release contains contributions from (in alphabetical order):

Lillian Frederiksen
Francesco Scala


---

Improvements 🛠

* Stop using the now-deprecated `tape.is_sampled` property.
[(348)](https://github.com/PennyLaneAI/pennylane-qiskit/pull/348)

Bug fixes 🐛

* Update conversion of PennyLane to Qiskit operators to accommodate
the addition of Singleton classes in the newest version of Qiskit.
[(347)](https://github.com/PennyLaneAI/pennylane-qiskit/pull/347)

Contributors ✍️

This release contains contributions from (in alphabetical order):

Lillian Frederiksen,
Matthew Silverman

---

Improvements 🛠

* Logic updated to support Aer V2 device naming conventions.
[(343)](https://github.com/PennyLaneAI/pennylane-qiskit/pull/343)

Breaking changes 💔

* The old return type system has been removed.
[(331)](https://github.com/PennyLaneAI/pennylane-qiskit/pull/331)

Contributors ✍️

This release contains contributions from (in alphabetical order):

Mudit Pandey,
Matthew Silverman

---

Improvements 🛠

* Added support for `qml.StatePrep` as a state preparation operation.
[(326)](https://github.com/PennyLaneAI/pennylane-qiskit/pull/326)

Breaking changes 💔

* Support for Python 3.8 has been removed.
[(328)](https://github.com/PennyLaneAI/pennylane-qiskit/pull/328)

Contributors ✍️

This release contains contributions from (in alphabetical order):

Mudit Pandey,
Jay Soni,

---