Contribution to import QuantumCircuits from Qiskit/OpenQASM

[QuantumRaul]

Summary

This PR adds two new functions to enable interoperability between Qiskit and CUDA-Q:

• cudaq.from_qiskit(qiskit_circuit): Converts a Qiskit QuantumCircuit to a CUDA-Q kernel
• cudaq.from_qasm(file_path): Loads an OpenQASM file and converts it to a CUDA-Q kernel

Supported Gates

Category	Gates
Single qubit	h, x, y, z, s, t, sdg, tdg, id
Two qubit	cx, cy, cz, ch, swap, rxx, rzz
Three qubit	ccx (Toffoli)
Parametric	rx, ry, rz, r1, p, u3, u
Controlled parametric	crx, cry, crz
Special	sx, sxdg, barrier, measure

Example Usage

from qiskit import QuantumCircuit
import cudaq

# Create a Bell state in Qiskit
qc = QuantumCircuit(2)
qc.h(0)
qc.cx(0, 1)

# Convert to CUDA-Q and run on GPU
kernel = cudaq.from_qiskit(qc)
result = cudaq.sample(kernel)
print(result)  # {'00': 500, '11': 500}

Documentation

Documentation is provided via comprehensive docstrings in the source code.
Additional user guide documentation can be added in a follow-up PR if desired.

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[bettinaheim]

@QuantumRaul Thank you for this contribution!
We would like to move this to a cudaq.contrib module that contains features that are maintained by the community. While the corresponding C++ namespace already exists, a matching Python module has not yet been set up. Do you want to give it a try to do that?

[QuantumRaul]

@bettinaheim Sure, I will start working on building the contrib module. I'll give it a try and I will reach you with any news.

[QuantumRaul]

@bettinaheim Just finished creating the contrib module, and added to it the functions I builded before. Also reviewed the imports at init.py

[bettinaheim]

/ok to test 685a8a7

Command Bot: Processing...

[schweitzpgi]

nit: Copyright for new files ought to be simply 2026, I believe.