Tutorial: Inelastic Neutron Scattering in the Quasiparticle Zoo: Magnons, Spinons, Bound States, and Their Interactions

SPICE Workshop on Quantum Geometry and Transport of Collective Excitations in (Non-)Magnetic Insulators, May 6th - 8th 2025

Martin Mourigal

Inelastic neutron scattering is a powerful technique for probing the collective excitations of magnetic solids. In this tutorial, I will review the basic theory of inelastic neutron scattering from spin systems in thermodynamic equilibrium. To illustrate this rich topic, I will discuss examples from my research that quantitatively explore the nature and interactions of quasiparticles. In particular, I will emphasize recent advances in modelling approaches that enable a one-to-one correspondence between theory and experiment. I will also highlight frontier topics in inelastic neutron scattering, such as topological effects, entanglement witnesses, the role of quenched disorder, and transient/non-equilibrium phenomena. Time permitting, I will discuss emerging neutron scattering instruments expected to expand research opportunities from the 2030s and beyond.