The Antimagnonics

Magnons are the quanta of collective spin excitations in magnetically ordered systems, and manipulation of magnons for computing and information processing has witnessed the development of "magnonics." A magnon corresponds to an excitation of the magnetic system from its ground state, and the creation of a magnon thus increases the total energy of the system. In this perspective, we introduce the antiparticle of a magnon, dubbed the antimagnon, as an excitation that lowers the magnetic energy. On the fundamental side, the introduction of antimagnons paves the way to study phenomena from high-energy physics that are hard to observe with elementary particles, such as the Klein effect, black-hole horizons, and black-hole lasing, in a condensed-matter setting. On the application side, the introduction of antimagnons yields physical intuition for schemes to amplify magnons that may eventually find applications in magnonics, and this is often based on analogies of the aforementioned high-energy phenomena. We investigate the stability and thermal occupation of antimagnons and verify our theory by micromagnetic simulations. We hope that our work stimulates fundamental interest in antimagnons, as well as their applications to spintronic devices. (c) 2024 Author(s).