Dynamiqs is a high-performance, differentiable quantum simulation library built on JAX. It solves the Schrödinger equation, Lindblad master equation, diffusive and jump stochastic master equations, and computes propagators and Floquet modes. The library is designed for GPU acceleration and scales to batched simulations over many Hamiltonians, initial states, or parameters. It provides machine-precision gradients via forward and reverse-mode automatic differentiation, making it suitable for quantum optimal control and parameter estimation. The architecture is modular: a hierarchy of integrators (adaptive ODE solvers via Diffrax, fixed-step Rouchon, matrix exponentiation, low-rank, and event-based) is coupled with custom array representations (dense and sparse diagonal DIA via DataArray subclasses). Time-dependent operators are supported through a hierarchy of TimeQArray classes. The library also includes plotting utilities, random state/operator generation, and extensive verification against analytical solutions. External dependencies include JAX, Diffrax, Equinox, and QuTiP (for compatibility). The codebase demonstrates strong engineering with a comprehensive test suite (including gradient and stochastic property tests), benchmark infrastructure, and CI/CD pipelines. It is used by the startup Alice & Bob for cat-qubit control and is under active development with a rapidly evolving API.
PyRPL is a Python library and GUI application that turns a Red Pitaya / STEMlab FPGA board into a multi-instrument real-time digital servo controller for quantum optics experiments. It provides hardware modules (PID, IIR filter, IQ modulator/demodulator, arbitrary signal generator, scope, trigger, PWM, etc.) and software modules (lockbox, network analyzer, spectrum analyzer, curve viewer). The system is used primarily for laser frequency stabilization (e.g., PDH locking) and phase-locked loops. Communication with the FPGA occurs over SSH and a custom low-latency TCP monitor server. A full Qt-based GUI allows live data display and module configuration. The repository also includes the complete FPGA firmware source (Verilog, Vivado TCL) for the Red Pitaya board, example Jupyter notebooks with experimental data, and CI pipelines for hardware-in-the-loop testing. While the core application is mature and actively used in research, the codebase carries legacy artifacts (old CI configs, Python 2 workarounds) and the FPGA design has unresolved timing violations.