cirq-core

library1.7.0pypypi✓ verified 24d ago

Cirq is a Python framework developed by Google's Quantum AI team for creating, editing, and invoking Noisy Intermediate Scale Quantum (NISQ) circuits. It focuses on providing fine-tuned control over quantum circuits and gate-level operations for current-generation quantum processors. The library is actively maintained, with frequent releases, and is currently at version 1.6.1.

ai-ml data

pip install cirq

github ↗package ↗homepage ↗

INSTALL

IMPORT

SIG · CIRQ-CORE

cirq-core

ai-mlpythonv1.7.0

Install

23.8s avg

Import

5918ms

Disk

604MB

Pass rate

6/ 10

Env Coverage6 / 10

glibc

3.9–3.13

musl

3.9–3.13

Install & Compatibility

Where this runs

tested against v1.5.0 · pip install

no network on importno background threads

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

glibc

py 3.10

1/2 runs

✓ 27.15s

py 3.11

1/2 runs

✓ 24.8s

py 3.12

1/2 runs

✓ 26s

py 3.13

1/2 runs

✓ 25.4s

py 3.9

✓ 0.05s

✓ 39.4s

604MB installed

● package 604MB

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

cirq

✓ import cirq

The main top-level package for all core functionalities.

LineQubit

✓ import cirq # ... q0, q1 = cirq.LineQubit.range(2)

✗ from cirq.devices import LineQubit

Many common classes and functions are exposed directly under the `cirq` namespace for convenience, avoiding deeper module imports.

Simulator

✓ import cirq # ... simulator = cirq.Simulator()

✗ from cirq.simulators import Simulator

Simulators are often accessed directly via `cirq.Simulator`.

This quickstart demonstrates how to build a basic quantum circuit, simulate it using Cirq's built-in simulator, and retrieve measurement results as a histogram. It creates a Bell state using Hadamard and CNOT gates and then measures both qubits.

import cirq import numpy as np # Create two qubits q0, q1 = cirq.LineQubit.range(2) # Build a simple Bell state circuit circuit = cirq.Circuit( cirq.H(q0), cirq.CNOT(q0, q1), cirq.measure(q0, q1, key='result') ) print("Circuit:") print(circuit) # Simulate the circuit 1000 times simulator = cirq.Simulator() result = simulator.run(circuit, repetitions=1000) # Display the measurement results print("\nMeasurement results (histogram):") print(result.histogram(key='result'))

cirq --version

Debug

Known issues

breakingThe minimum required Python version has been increased to 3.11.0. Older Python versions are no longer supported.

fix

Upgrade your Python environment to 3.11.0 or later. Consider using a virtual environment (e.g., `python -m venv .venv`).

affects: >=1.6.0

breakingThe `cirq-rigetti` subpackage has been completely removed from the main `cirq` distribution. It was previously deprecated in v1.5.0.

fix

For legacy code requiring `cirq-rigetti` functionality, use the last standalone release `cirq-rigetti-1.5.0`. Alternatively, migrate to other supported hardware integrations or the standalone `pyquil` library.

affects: >=1.6.0

breakingThe `cirq-ft` package (for fault-tolerant resource estimation) was removed from Cirq. It was deprecated in v1.3.0.

fix

The functionality of `cirq-ft` has been moved to the `Qualtran` repository. Users should now use the `Qualtran` library for fault-tolerant resource estimation needs.

affects: >=1.4.0

deprecatedThe `cirq-rigetti` subpackage was deprecated and became an opt-in component, requiring explicit installation.

fix

If still using Cirq versions <1.6.0 and needing Rigetti integration, install it explicitly via `pip install cirq-rigetti`. For versions >=1.6.0, refer to the breaking change above.

affects: >=1.5.0, <1.6.0

gotchaA bug in `cirq.kraus` could return erroneous near-zero matrices, potentially affecting simulations or analysis involving Kraus operators.

fix

Upgrade to Cirq v1.6.1 or later to get the fix for the `cirq.kraus` bug.

affects: 1.6.0

gotchaWhile Cirq v1.0.0 brought a commitment to API stability following SemVer, earlier versions (pre-1.0) were in an 'alpha' state with frequent breaking changes between releases.

fix

When working with older Cirq codebases, it is crucial to pin to specific minor versions (`cirq==0.X.Y`) and be prepared for migrations if upgrading to newer major versions. For current development, rely on the stated SemVer compatibility.

affects: <1.0.0

Errors

Common errors & fixes

AttributeError: module 'cirq' has no attribute 'GridQubit'

This error often occurs when a user's Python file is named `cirq.py`, causing Python to import the local file instead of the installed `cirq` library, leading to a module shadowing issue.

fix

Rename your Python file to something other than `cirq.py` (e.g., `my_quantum_program.py`). If the issue persists, ensure Cirq is correctly installed with `pip install cirq-core` or `pip install cirq`.

AttributeError: module 'cirq' has no attribute 'google'

Cirq underwent modularization, and components related to Google's quantum hardware, previously under `cirq.google`, were moved to a separate package, `cirq_google`.

fix

Install the `cirq_google` package (`pip install cirq-google`) and change your import statements from `import cirq.google` to `import cirq_google`.

ModuleNotFoundError: No module named 'cirq'

This error indicates that the `cirq` or `cirq-core` package has not been installed in your Python environment or is not accessible in the current environment's Python path.

fix

Install the `cirq-core` library using pip: `pip install cirq-core`. If you need all optional modules, use `pip install cirq`.

type object 'Circuit' has no attribute 'from_ops'

The `from_ops` method for creating a `cirq.Circuit` has been deprecated in newer versions of Cirq.

fix

Instead of `cirq.Circuit.from_ops(ops)`, you can directly pass the operations as arguments to the `cirq.Circuit` constructor: `cirq.Circuit(*ops)`.

Upgrade

Version history

1.7.0latest on PyPI · released Jun 29, 2026

Audit

Dependencies

pythonrequiredMinimum required Python version for Cirq 1.6.x

cirq-googleoptionalFor integration with Google's quantum processors (e.g., Sycamore, Weber)

cirq-ionqoptionalFor integration with IonQ trapped ion quantum computers

cirq-aqtoptionalFor integration with Alpine Quantum Technologies (AQT) hardware

cirq-pasqaloptionalFor integration with Pasqal neutral atom quantum computers

azure-quantumoptionalFor integration with Azure Quantum (IonQ and Honeywell backends)

Agent activity

20 hits · last 30 days

node

Amazon

OpenAI (training)

Resources

githubhttp://github.com/quantumlib/cirq ↗

packagehttps://pypi.org/project/cirq-core/ ↗

homepagehttps://quantumai.google/cirq ↗