SKM 2023 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 65: Correlated Electrons: Other Theoretical Topics
TT 65.3: Vortrag
Freitag, 31. März 2023, 10:00–10:15, HSZ 204
Collapse of fermionic quasiparticles upon coupling to local bosons — Adam Kłosiński, Piotr Wrzosek, Krzysztof Wohlfeld, and •Cliò Efthimia Agrapidis — Insitute of Theoretical Physics, Faculty of Physics, University of Warsaw, Poland
We study the stability of the fermionic quasiparticle in a fermion-boson model on a Bethe lattice, with fermions interacting with local bosons thorough a Peierls coupling. We solve the model by mapping it onto a non-interacting chain with a site-dependent potential. We show that the model does not support a quasiparticle solution – provided that a finite number of local bosonic excitations cost zero energy. The quasiparticle disappearance becomes easier with an increase in: (i) the total number of bosons with zero energy, and (ii) the relative strength of the coupling between bosons and fermions. The postulated model can be applied to study systems in which fermions are coupled to condensed bosons or magnons in spin stripes embedded in hole-doped 2D antiferromagnets or Ising-like magnetic interfaces (ferromagnetic-antiferromagnetic). Finally, we show how this model leads to an in-depth understanding of the onset of quasiparticles in the 1D and 2D t-Jz model.