OpenQASM 3 integer literals should use integer division

[DanBlackwell]

Describe the bug After some discussion here: https://github.com/Qiskit/qiskit/issues/12167, it seems that the stdgates.inc definition gate sx a { pow(1/2) @ x a; } should have the 1/2 resolve to 0 thanks to integer division (i.e. stdgates.inc has an incorrect definition of sx gate). As it stands, it seems that when interpreting openQASM 3, the Braket sim treats these values as floats (which makes that sx gate definition behave correctly). Apparently the relevant part of the specification is here: https://openqasm.com/language/classical.html#integers.

Being as 'fixing' this would break stdgates.inc as of right now, I don't think it should be 'fixed' yet. I'm not even sure how closely Braket promises to follow the openQASM specification, so perhaps it's a non-issue.

To reproduce

from braket.circuits import Circuit
from braket.devices import LocalSimulator

device = LocalSimulator()
quantum_circuit = Circuit.from_ir('''
OPENQASM 3.0;
include "stdgates.inc";
qubit[1] q;
ry(1/2) q;
''')
quantum_circuit.probability()
res = device.run(quantum_circuit, 0)
print(res.result().values)

Expected behavior The ry(1/2) should resolve to ry(0) here resulting in a 1.0 probability of q being 0. To use floating point division it would need to be 1.0 / 2, 1 / 2.0 or 1.0 / 2.0.

Screenshots or logs Actual output: [array([0.93879128, 0.06120872])]

System information A description of your system. Please provide:

• Amazon Braket Python SDK version: v1.74.0
• Amazon Braket Python Schemas version:
• Amazon Braket Python Default Simulator version:
• Python version: Python 3.10.12

Additional context N/A

[ashlhans]

Hi @DanBlackwell - thank you for raising this issue! We will look into this.

[speller26]

stdgates.inc will be fixed in https://github.com/openqasm/openqasm/pull/529, so #247 will work fine with it