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DTSTART;VALUE=DATE:20240229T131500
DTEND;VALUE=DATE:20240229T131500
UID:15125@agenda.unifr.ch
DESCRIPTION:One of the main paradigms of quantum magnetism is that collective\nexcitations in systems with long-range order, such as ferro- or\nantiferro-magnets, are well described in terms of bosonic\nquasiparticles -- magnons. This approach is extremely successful,\nsince these magnons very weakly interact. On the other hand, once the\nlong-range order collapses, for instance due to geometric (or\ndoping-induced) frustration of spin couplings, magnons interact and\nsuch a description seems to fail. Instead the low-energy magnetic\nexcitations are typically described in terms of fermionic spinons.\nUnfortunately the latter quasiparticles are less intuitive, for they\ncarry fractional quantum numbers and, often, they also do interact.\n\nIn this talk I will first give a not-so-standard but intuitive\nunderstanding of both magnons [1] and spinons [2]. Next, I will\ndiscuss whether the observed with RIXS persistence of collective spin\nexcitations in the high-Tc cuprates is better described in terms of\nspinons [3] or magnons [4].\n\nReferences:\n[1] P. Wrzosek et al.; Physical Review B 102, 02440 (2020).\n[2] T. Kulka et al, arXiv:2303.02276 (under review in Phys. Rev. Lett).\n[3] YF Kung et al., Physical Review B 96, 195106 (2017); E.M. Paerschke et \nal., Physical Review B 99, 205102 (2019).\n[4] W. Zhang et al., npj Quantum Mater. 7, 123 (2022).
SUMMARY:Spinons or magnons? A quest for the correct quasiparticle description of quantum magnets
CATEGORIES:Séminaire
LOCATION:PER 08\, 0.51\, Chemin du Musée 3\, 1700 Fribourg
URL;VALUE=URI:https://agenda.unifr.ch/e/fr/15125
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