SPiin

SPiin (Spin Processing and Interaction Network) is an open-source software framework designed to simulate and analyze spin systems in condensed matter physics and materials science. It provides tools to construct spin Hamiltonians on arbitrary networks, run numerical simulations, and visualize results.

Origin and development: SPiin was conceived by researchers as a modular platform for comparing spin models across lattices and graphs. The project emphasizes extensibility and interoperability with existing scientific Python ecosystems, and it is maintained by a community of contributors from physics and computational science.

Key features: SPiin supports common spin models such as Heisenberg, Ising, XY, and Dzyaloshinskii–Moriya interactions; arbitrary lattice or network topologies; and multiple simulation engines, including Monte Carlo sampling, exact diagonalization for small systems, and mean-field approaches. It uses sparse linear algebra backends and offers convenient Python bindings, with optional C++ cores for performance. Visualization tools and data exporters facilitate analysis and reproducibility.

Applications: The framework is used in theoretical studies of magnetic phase transitions, spin glasses, and spintronics materials; educational use in teaching quantum many-body physics; and rapid prototyping of model Hamiltonians for experimental collaboration.

See also: spin model, Heisenberg model, Ising model, Monte Carlo method.