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arXiv · 2510.11776

Adjoint ferromagnets

Joaquín López-Suárez·Alexios P. Polychronakos·Konstantinos Sfetsos
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Abstract

We derive the phase structure and thermodynamics of ferromagnets consisting of elementary magnets carrying the adjoint representation of $SU(N)$ and coupled through two-body quadratic interactions. Such systems have a continuous $SU(N)$ symmetry as well as a discrete conjugation symmetry. We uncover a rich spectrum of phases and transitions, involving a paramagnetic and two distinct ferromagnetic phases that can coexist as stable and metastable states in different combinations over a range of temperatures. The ferromagnetic phases break $SU(N)$ invariance in various channels, leading to spontaneous magnetization. Interestingly, the conjugation symmetry also breaks over a range of temperatures and group ranks $N$, providing a realization of a spontaneously broken discrete symmetry.

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Joaquín López-Suárez, Alexios P. Polychronakos, Konstantinos Sfetsos. 2025-10-13. Adjoint ferromagnets. https://doi.org/10.1016/j.nuclphysb.2025.117287

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