Speakers: Andrii Sotnikov (Akhiezer Institute for Theoretical Physics, NSC KIPT, Kharkiv, Ukraine)
Place: Na Slovance, main lecture hall
Presented in English
Organisers:
Department of Condensed Matter Theory
Abstract:
We study finite-temperature magnetic phases in three-component mixtures of ultracold fermionic
atoms with repulsive interactions in optical lattices by means of dynamical mean-field theory. In the
case of one particle per site (1/3 band filling) and depending on the on-site interaction strength in the
Hubbard model, we obtain a hierarchy of critical temperatures corresponding to transitions to
antiferromagnetic states with different sublattice orderings, in agreement with the limit of the SU(3)
Heisenberg model, studied in [1].
We discuss the case of a complete SU(3) symmetry between different spin components, as well
as the effect of the asymmetry in interspecies interactions on the long-range-ordered magnetic phases
and the corresponding critical temperatures [2]. Different types of antiferromagnetic states (2- and 3-
sublattice color-density waves, color-selective antiferromagnetic order) and peculiar induced effects are
studied in detail. According to the quantitative entropy analysis [3], we conclude that 2-sublattice
antiferromagnetic states should be observable in three-component mixtures at higher entropies than in
two-component mixtures that is explained by the stronger Pomeranchuk effect [4]. Therefore, these
systems have clear advantages in approaching long-range ordered quantum phases in experiments with
ultracold atomic mixtures in optical lattices.
[1] T. Tóth, A. Läuchli, F. Mila, and K. Penc, Phys. Rev. Lett. 105, 265301 (2010).
[2] A. Sotnikov and W. Hofstetter, Phys. Rev. A 89, 063601, (2014).
[3] A. Sotnikov, preprint, arXiv:1506.07642 (2015).
[4] S. Taie, R. Yamazaki, S. Sugawa, and Y. Takahashi, Nat. Phys. 8, 825, (2012).
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