Update plugin to natively support Ugate, Pgate, and SXgate

The Ugate is the new Qiskit label for the U3gate
The Pgate corresponds to the PennyLane PhaseShift operation
The SXgate (sqrtX gate) is new, and currently does not have a PennyLane native equivalent.
Qiskit has deprecated the [u1, u2, u3] basis in favour of the new [p, sx] basis.

Once the above gates are natively available in PennyLane, we should update the plugin to use the newly available gates.

Hey! Is this issue still open? The SXgate is now supported and cant be used in the plugin too right? I understand Ugate and Pgate have already been updated in the v0.23 update.

Hi @charmerDark, having a look at the Qiskit device's supported operations,

pennylane-qiskit/pennylane_qiskit/qiskit_device.py

Line 36 in 5793462

QISKIT_OPERATION_MAP = {

it appears that SX is not yet listed. Further, ex.PhaseGate and ex.U3Gate currently in used by the plugin might be deprecated by Qiskit and could be in need of an update!

So I would say that this issue is still valid, yes.

Hey! Is this issue still open? The SXgate is now supported and cant be used in the plugin too right? I understand Ugate and Pgate have already been updated in the v0.23 update.

I'm sorry..I meant now that SX is available on pennylane, it could be added to the list of supported operations. the 'cant' was a typo 😅

Ah I see, yes definitely @charmerDark!