Quantum Framework
Cirq
Cirq is Google's open-source framework for programming and simulating quantum circuits at the gate level. It is designed for near-term noisy intermediate-scale quantum (NISQ) devices and provides fine-grained control over gate schedules, qubit placement, and circuit optimization. Used internally by Google for quantum supremacy and error correction experiments.
Overview
Maintainer
Google Quantum AI
Language(s)
Version
1.x
Supported Architectures
Cloud Platforms
Installation
pip install cirq # For Google Quantum AI hardware: pip install cirq-google
Requires Python 3.10+. `cirq` installs the core framework with local simulation. `cirq-google` is needed for Google Quantum AI hardware access (requires project approval). For IonQ backend: `pip install cirq-ionq`.
Bell State Example
A Bell state (maximally entangled two-qubit state) is the canonical first circuit for any quantum framework.
import cirq
q0, q1 = cirq.LineQubit.range(2)
circuit = cirq.Circuit([
cirq.H(q0),
cirq.CNOT(q0, q1),
cirq.measure(q0, q1, key='result')
])
# Local simulation
simulator = cirq.Simulator()
result = simulator.run(circuit, repetitions=1024)
# Google hardware (requires access approval)
import cirq_google
engine = cirq_google.Engine(project_id='your-project-id')Cloud Access
Google Quantum AI hardware is available to approved research partners via `cirq-google`. Access requires submitting an application to the Google Quantum AI program. IonQ hardware is accessible via `cirq-ionq`. AWS Braket also supports Cirq-native circuits through its SDK integration.
Provider Compatibility
| Provider | Access Method | Notes |
|---|---|---|
| Google Quantum AI | cirq-google (native) | Requires research access approval from Google Quantum AI program |
| IonQ | cirq-ionq plugin | pip install cirq-ionq; supports IonQ Harmony and Forte via native gates |
| Pasqal | cirq-pasqal plugin | pip install cirq-pasqal; neutral-atom gate emulation and hardware targets |