Critical entropies and magnetic-phase-diagram analysis of ultracold three-component fermionic mixtures in optical lattices

Abstract

We study theoretically many-body equilibrium magnetic phases and corresponding thermodynamic characteristics of ultracold three-component fermionic mixtures in optical lattices described by the SU(3)-symmetric single-band Hubbard model. Our analysis is based on the generalization of the exact diagonalization solver for multicomponent mixtures that is used in the framework of the dynamical mean-field theory. It allows us to obtain a finite-temperature phase diagram with the corresponding transition lines to magnetically ordered phases at filling one particle per site (1/3 band filling) in simple cubic lattice geometry. Based on the developed theoretical approach, we also attain the necessary accuracy to study the entropy dependence in the vicinity of magnetically ordered phases that allows us to make important predictions for ongoing and future experiments aiming to approach and study long-range-order phases in ultracold atomic mixtures.

Interplay between intrinsic and emergent topological protection on interacting helical modes

“…We also find that the low energy fix point has a higher symmetry with respect to interaction between modes that the original model, signalling a dynamically emergent symmetry. This phenomenon was previously observed in the context of three leg ladders [61][62][63][64][65][66][67][68][69][70][71][72]. In our case, the massive phases are ground states of a Hamiltonian that is obtained by marginal deformations of an emergent SU(3) symmetry, which is not present in the UV, but that manifest itself in the IR.…”

Breaking of SU(4) symmetry and interplay between strongly correlated phases in the Hubbard model

“…This result is in stark contrast to the well-studied case of the two-component SU(2)symmetric Hubbard model at half filling, where the corresponding transition is of the second order at any coupling strength U/t. It also differs substantially from the low-temperature characteristics of the three-component SU(3)-symmetric Hubbard model on a simple cubic lattice at n = 1 (1/3 band filling), where the transition is of the first order, but appears only at a moderate coupling U c ≈ 9.6t in the T = 0 limit [32]. In Fig.…”

“…To solve the impurity problem, we mostly employ the exact-diagonalization (ED) solver [31] since it is fast and reliable in most regimes of interest. Moreover, building upon the generalized version for multicomponent mixtures [32], it can be extended to account for the spin-flip term in a straightforward way (see the Appendix A for more details). In places, a continuous-time quantum Monte Carlo hybridization expansion solver (CT-HYB) in the segment representation [33,34] is used to benchmark the accuracy of the obtained results for the SU(4)-symmetric system.…”

Orbital magnetism of ultracold fermionic gases in a lattice: Dynamical mean-field approach

“…The quantities lασ and V lασ (bath's energies and hybridization amplitudes, respectively) are the so-called Anderson parameters that are determined self-consistently within the DMFT iterative procedure. To solve the effective quantum impurity problem, we use the ED method [45,49,50] as well as the continuous-time quantum Monte-Carlo hybridization expansion solver (CT-HYB) (see Refs. [38,51,52] for details).…”

“…However, the single-site or two-sublattice DMFT selfconsistency conditions introduced above are obviously not enough to capture more exotic types of magnetic order (see, e.g., Ref. [50]). In this case, the real-space generalization of DMFT (RDMFT) is required [53,54].…”