Sunny.jl: A Julia Package for Spin Dynamics

TL;DR

Sunny.jl is a Julia package that provides comprehensive tools for simulating and analyzing spin dynamics in quantum magnetism, supporting diverse models, advanced methods, and experimental comparisons.

Contribution

It introduces a broad generalization of classical and semiclassical approaches to SU(N) coherent states within a user-friendly Julia package.

Findings

Supports a wide range of spin models and solvers

Enables simulation of spin dynamics in and out of equilibrium

Facilitates comparison with scattering experiments

Abstract

Sunny is a Julia package designed to serve the needs of the quantum magnetism community. It supports the specification of a very broad class of spin models and a diverse suite of numerical solvers. These include powerful methods for simulating spin dynamics both in and out of equilibrium. Uniquely, it features a broad generalization of classical and semiclassical approaches to SU(N) coherent states, which is useful for studying systems exhibiting strong spin-orbit coupling or local entanglement effects. Sunny also offers a well-developed framework for calculating the dynamical spin structure factor, enabling direct comparison with scattering experiments. Ease of use is a priority, with tools for symmetry-guided modeling and interactive visualization.