Speaker
Description
One of the main paradigms of quantum magnetism is that collective excitations in systems with long-range order, such as ferro- or antiferro-magnets, are well described in terms of bosonic quasiparticles -- magnons. This approach has been extremely successful, largely because magnons interact only weakly.
However, when long-range order collapses -- for example, due to geometric frustration or doping-induced disruption of spin couplings -- magnons begin to interact strongly, and this description breaks down. In such cases, the low-energy magnetic excitations are typically described in terms of spinons. Unfortunately, spinons are less intuitive, as they carry fractional quantum numbers and obey fractional statistics.
In this talk, I will first explain our recent efforts to develop an intuitive understanding of both the magnon [1] and the spinon [2], thereby highlighting the intrinsic differences between these two quasiparticles. In the second part of the talk, I will briefly discuss the extent to which a spinon- or magnon-based approach better explains some of the most well-known experimental magnetic spectra of high-Tc cuprates [3].
[1] P. Wrzosek et al.; Phys. Rev. B 102, 02440 (2020).
[2] T. Kulka et al., Phys. Rev. Lett. 134, 236504 (2025).
[3] Y.F. Kung et al., Phys. Rev. B 96, 195106 (2017); E.M. Paerschke et al., Phys. Rev. B 99, 205102 (2019); W. Zhang et al., npj Quantum Mater. 7, 123 (2022).
