CONVENER

Bruno Tomasello (University of Catania, Italy)

Tim Ziman (Institut Laue-Langevin, Grenoble, France)

MEMBERS

Michiyasu Mori (Japanese Atomic Energy Agency, Japan)

Kei Yamamoto (Japanese Atomic Energy Agency, Japan)

Tomi Ohtsuki (Sophia University, Japan)

Keith Martin Slevin (Osaka University, Japan) 

Kyoung-Min Kim (APCTP, Korea)

Moon Jip Park (Hanyang University, Korea)

Alexei Andreanov (PCS IBS, Korea)

Oleg Utesov (PCS IBS, Korea)

Se Kwon Kim (KAIST, Korea)

OVERVIEW

This Advanced Study Group will address key theoretical challenges in quantum magnets with complex anisotropies, building on recent progress in understanding how crystal-field wavefunctions inform dipolar and higher multipolar moments under different perturbations. Over the years, perturbative, mean-field, and exact diagonalisation approaches have been de- veloped to scrutinise the intricate magnetic structures and dynamics of rare-earth iron garnets, in which a complex network of rare-earth and iron ions compete through single-ion anisotropies and non-collinear interactions.

A key goal of this ASG is to extend and generalise the theoretical description of mag- netic excitations in materials where flat magnon bands can emerge from both crystal field effects and topological mechanisms. Collaborating with PCS experts in magnetism, flat-band physics, and machine learning, we will explore how new analysis and computa- tion can help disentangle the above effects and will explore the ongoing theoretical challenges.

Beyond garnets, we aim to bridge quantum magnetism and spintronics, motivated by recent studies on single-ion anisotropies in many-body localization and non-ergodicity, as well as their role in topological conducting materials like Weyl semimetals. This ASG will provide a unique setting to refine theoretical frameworks, identify open problems, and develop new collaborative directions in these emerging fields.