Learn CIRQ with Real Code Examples

Cirq allows developers to create and manipulate quantum circuits at the gate level.

It provides simulation tools as well as interfaces for running circuits on Google quantum hardware.

Cirq emphasizes control over noise, pulse-level operations, and optimization of circuits for near-term quantum devices.

Quantum circuit creation using `cirq.Circuit`

Qubit definition with `cirq.GridQubit` or `cirq.LineQubit`

Gate operations like `X`, `H`, `CNOT`, and custom gates

Simulation via `cirq.Simulator` with or without noise

Measurement and sampling analysis tools

Qubit: fundamental quantum information unit

Circuit: sequence of quantum gates applied to qubits

Gate: quantum operation applied to qubits

Moment: collection of gates applied simultaneously

Simulator/Backend: environment to run circuits (classical or quantum hardware)

Notebooks/ - experiments and tutorials

Circuits/ - custom quantum circuit definitions

Simulations/ - results from simulator or hardware

Data/ - measurement and analysis results

Scripts/ - utility and automation scripts

Import Cirq and define qubits

Create gates and build a quantum circuit

Group gates into moments for scheduling

Simulate circuit using `cirq.Simulator`

Measure qubits and analyze results

Beginner: simulate basic gates and entanglement

Intermediate: implement small quantum algorithms (Grover, Bernstein-Vazirani)

Advanced: optimize circuits for noise mitigation

Expert: pulse-level and error-aware programming

Enterprise: integrate with classical pipelines for hybrid algorithms

Cirq vs Qiskit: Cirq targets Google hardware, Qiskit targets IBM devices

Cirq vs Pennylane: Cirq focuses on NISQ circuits, Pennylane emphasizes quantum ML

Cirq vs Braket: Braket supports multi-cloud, Cirq is Google-focused

Cirq vs PyQuil: PyQuil is for Rigetti hardware, Cirq is Google-focused

Cirq vs ProjectQ: Cirq is more NISQ-oriented with gate-level control

2017 – Initial Cirq development by Google Research

2018 – Cirq open-sourced

2019 – Integration with Google Quantum Engine

2020 – Noise modeling and optimizers introduced

2023 – Enhanced hybrid ML and pulse-level controls

Qubit: fundamental quantum information unit

Gate: quantum operation applied to qubits

Circuit: sequence of gates applied to qubits

Moment: collection of gates applied simultaneously

Simulator: classical tool to emulate quantum circuit behavior