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Q: Fachverband Quantenoptik und Photonik
Q 9: Cold atoms II - interactions (joint session A/Q)
Q 9.5: Vortrag
Montag, 5. März 2018, 11:30–11:45, K 2.019
Breaking of SU(4) symmetry and interplay between strongly correlated phases in the Hubbard model — •Agnieszka Cichy1,2 and Andrii Sotnikov3,4 — 1Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznan, Poland — 2Umultowska 85 — 3Institute of Solid State Physics, TU Wien, Wiedner Hauptstr. 8, 1040 Wien, Austria — 4Akhiezer Institute for Theoretical Physics, NSC KIPT, 61108 Kharkiv, Ukraine
We study the thermodynamic properties of four-component fermionic mixtures described by the Hubbard model using the dynamical mean-field-theory approach. Special attention is given to the system with SU(4)-symmetric interactions at half filling, where we analyze equilibrium many-body phases and their coexistence regions at nonzero temperature for the case of simple cubic lattice geometry. We also determine the evolution of observables in low-temperature phases while lowering the symmetry of the Hamiltonian towards the two-band Hubbard model. This is achieved by varying interflavor interactions or by introducing the spin-flip term (Hund's coupling). We observe a strong effect of suppression of ferromagnetic order in comparison with previous studies that were usually performed by restricting to density-density interactions. By calculating the entropy for different symmetries of the model, we determine the optimal regimes for approaching the studied phases in experiments with ultracold alkali and alkaline-earth-like atoms in optical lattices.