Altermagnetism has emerged as one of the most important research topics in spintronics, condensed matter physics, and materials sciences. It features compensated spin arrangements across sublattices linked by rotation or mirror rather than translational or inversion symmetry, resulting in zero net macroscopic magnetization like antiferromagnets, while exhibiting non-relativistic spin splitting, forming a rigorous spin-momentum locking due to the same rotational or mirror symmetry (i.e. C-paired spin-momentum locking), that gives rise to detectable spin-polarized signals typical of ferromagnets . This rare combination delivers key practical advantages: immunity to stray magnetic field interference and terahertz-scale switching speeds from their antiferromagnetic-like order, plus straightforward electrical/magneto-optical readout of spin states enabled by their spin-split band structure. Moreover, the intrinsic C-paired spin-momentum locking naturally serves as a playground to explore the interactions of multiple degrees of freedoms, leading to many unexplored interesting phases or properties of quantum matter.

The goal of this forum is to create a focused program on the new developments in altermagnetism and unconventional magnetism. We aim to bring together key theorists and experimentalists to review the current state of the field and to define future research directions. The forum scope will include new experimental and theoretical work on altermagnets, related quantum phases, and their novel properties.

We have chosen Hong Kong as the venue for this forum. As a well-connected international city, it is an ideal location to bring together scientists from the US, Europe, Japan, and China. Furthermore, Hong Kong's expanding condensed matter research community provides a strong local context for our discussions.