Rostock 2019 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 49: Quantum gases (Fermions) (joint session A/Q)

Q 49.3: Talk

Thursday, March 14, 2019, 14:30–14:45, S HS 1 Physik

Suppression and revival of long-range ferromagnetic order in the multiorbital Fermi-Hubbard model — •Agnieszka Cichy¹, Andrii Sotnikov², and Yeimer Zambrano¹ — ¹Adam Mickiewicz University, Poznań, Poland — ²Kharkiv Institute of Physics and Technology, Kharkiv, Ukraine

The impressive development of experimental techniques in ultracold quantum degenerate gases of alkaline-earth-like (e.g., ¹⁷³Yb) atoms in recent years has allowed investigation of strongly correlated multiorbital systems. Long-lived metastable electronic states in combination with decoupled nuclear spin give the opportunity to study the Hamiltonians beyond the possibilities of current alkali-based experiments. Motivated by recent experimental progress, by means of dynamical mean-field theory allowing for complete account of SU(2) rotational symmetry of interactions between spin-1/2 particles [1], we observe a strong effect of suppression of ferromagnetic order in the multiorbital Fermi-Hubbard model in comparison with a widely used restriction to density-density interactions. We analyze a connection to the double-exchange model and observe high importance of spin-flip processes there as well. Additional implications on the strongly correlated phases originating from differences between the optical-lattice realizations and interacting electrons in solid state systems are discussed.

[1] A. Sotnikov, A. Cichy, and J. Kuneš, Phys. Rev. B 97, 235157 (2018).