PyQuil

PyQuil is a Python library for quantum programming that provides an interface to write and run programs in the Quil language. Developed by Rigetti Computing, it is part of the company’s software stack for designing, simulating, and executing quantum circuits on both quantum hardware and simulators.

At its core, PyQuil offers a Pythonic way to construct quantum programs. Users can define quantum gates, create parametrized gates, and use DefGate to implement custom operations. The language also supports measurements and classical memory for simple feedback and conditional execution. Programs are built with the Program object and can include a mix of quantum and classical instructions. PyQuil integrates with the Quil compiler, quilc, to translate Quil programs into hardware-friendly instructions.

Execution with PyQuil can take place on a local Quantum Virtual Machine (QVM) for simulation or on Rigetti’s real quantum processing units (QPU) via Quantum Cloud Services (QCS). The get_qc function provides access to a chosen quantum computer, enabling users to run experiments, collect measurement data, and iterate on quantum algorithms. PyQuil supports utilities for running multiple trials, managing calibration data, and working with various simulators and backends.

The library is widely used in research and education for prototyping variational algorithms, gate synthesis, and quantum circuit experiments. It is open-source and designed to interoperate with Rigetti’s broader software ecosystem, including the Quil language, quilc compiler, and cloud-based quantum resources.