cirq-ionq

1.6.1 verified Mon Apr 27 auth: no python

A Cirq package to simulate and connect to IonQ quantum computers. Version 1.6.1, released as part of Cirq v1.6.1. Supports Python >=3.11.0. Releases follow Cirq's release cadence, approximately quarterly.

pip install cirq-ionq

Common errors

error ModuleNotFoundError: No module named 'cirq_ionq' ↓

cause cirq-ionq not installed or imported incorrectly (e.g., `cirq.ionq`).

fix

Run pip install cirq-ionq and import as from cirq_ionq import IonQDevice.

error ionq_rest: (403) Forbidden ↓

cause Invalid or missing API key. The IonQ API key is not set or is incorrect.

fix

Set the IONQ_API_KEY environment variable to a valid IonQ API key.

error google.api_core.exceptions.PermissionDenied: 403 The request is missing a valid API key. ↓

cause Similar to above; API key not provided.

fix

Provide API key via environment variable or constructor argument.

Warnings

breaking Python 3.11 minimum: From version 1.6.0, cirq-ionq requires Python >=3.11.0. Older Python versions will fail to install. ↓

fix Upgrade Python to 3.11 or later.

gotcha Import from cirq_ionq not cirq.ionq: The correct import path is `from cirq_ionq import ...`. Using `cirq.ionq` will raise ImportError. ↓

fix Use `from cirq_ionq import IonQSimulator`.

deprecated API key via environment variable: The IonQ API key must be set via the `IONQ_API_KEY` environment variable or passed to the sampler constructor. Passing via `cirq_ionq.Service` constructor is deprecated. ↓

fix Set `IONQ_API_KEY` env var or use `IonQSimulator(api_key=...)` as documented.

Imports

IonQDevice
wrong
```
from cirq.ionq import IonQDevice
```
correct
```
from cirq_ionq import IonQDevice
```
cirq-ionq is a separate namespace package; import from cirq_ionq.

IonQSimulator

wrong

from cirq.ionq import IonQSimulator

correct

from cirq_ionq import IonQSimulator

Same as above; use cirq_ionq.

Quickstart

Run a Bell state circuit on the IonQ simulator.

import cirq
from cirq_ionq import IonQSimulator

# Get API key from environment (set IONQ_API_KEY)
import os
api_key = os.environ.get('IONQ_API_KEY', '')
if not api_key:
    print('Set IONQ_API_KEY environment variable')
    exit(1)

simulator = IonQSimulator(api_key=api_key)
q0, q1 = cirq.LineQubit.range(2)
circuit = cirq.Circuit(cirq.H(q0), cirq.CNOT(q0, q1), cirq.measure(q0, q1))
result = simulator.run(circuit, repetitions=100)
print(result.histogram(key='0,1'))