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

Golubeva, Anna; Sotnikov, Andrii; Cichy, Agnieszka; Kuneš, J.; Hofstetter, Walter

doi:10.1103/physrevb.95.125108

Cited by 12 publications

(9 citation statements)

References 42 publications

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“…We studied the influence of spin symmetry (in particular, presence of the spin-flip term) in the interaction part of the Hamiltonian on the FM instability in the multiorbital Hubbard model by means of DMFT. We observe strong effects of suppression of FM phases when accounting for full spin-rotational symmetry in the two-orbital systems (in contrast to weaker effects for AFM ordering [19,21]). By considering the three-orbital model, it is shown that these effects become weaker (i.e., FM ordering effectively revives) with an increase of the number of active orbitals that agrees well with arguments based on suppression of quantum fluctuations due to approaching the limit of classical spins.…”

Section: Discussionmentioning

confidence: 71%

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Suppression and revival of long-range ferromagnetic order in the multiorbital Fermi-Hubbard model

2018

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By means of dynamical mean-field theory allowing for complete account of SU(2) rotational symmetry of interactions between spin-1/2 particles, 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. In the case of orbital degeneracy, we show that the suppression effect is the strongest in the two-orbital model (with effective spin S eff = 1) and significantly decreases when considering three orbitals (S eff = 3/2), thus magnetic ordering can effectively revive for the same range of parameters, in agreement with arguments based on vanishing of quantum fluctuations in the limit of classical spins (S eff → ∞). We analyze a connection to the double-exchange model and observe high importance of spin-flip processes there as well.arXiv:1802.02935v3 [cond-mat.str-el]

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Section: Discussionmentioning

confidence: 71%

“…[10] for a recent material-oriented analysis). Therefore, a significant effort has been made to account for the full rotational symmetry of two-particle interactions [11][12][13][14][15][16][17][18][19][20][21].…”

Section: Introductionmentioning

confidence: 99%

Suppression and revival of long-range ferromagnetic order in the multiorbital Fermi-Hubbard model

2018

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“…First, it is a simple limit of multi-orbital models such as those used to describe transition metal oxides [9][10][11], graphene's SU(4) spin-valley symmetry [12], and twisted-bilayer graphene [13][14][15][16][17]. Second, the SU(N ) FHM is predicted to display a variety of interesting and exotic phases even in very special limits, such as: the conventional N = 2 FHM, the N = 3 FHM [18][19][20][21][22][23][24][25][26][27], the N = 4 FHM at quarter filling [28,29], even values of N at half-filling [30][31][32][33][34][35][36][37], special N → ∞ limits [38][39][40][41][42], 1D chains [43][44][45][46][47][48][49], and the Heisenberg limit for N = 3, 4, 5 [10,26,[50][51][52][53]…”

Section: Introductionmentioning

confidence: 99%

Universal thermodynamics of an SU($N$) Fermi-Hubbard Model

Ibarra-García-Padilla,

Dasgupta,

Wei

et al. 2021

Preprint

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The SU(2) symmetric Fermi-Hubbard model (FHM) plays an essential role in strongly correlated fermionic many-body systems. In the one particle per site and strongly interacting limit U/t 1, it is effectively described by the Heisenberg Hamiltonian. In this limit, enlarging the spin and extending the typical SU(2) symmetry to SU(N ) has been predicted to give exotic phases of matter in the ground state, with a complicated dependence on N . This raises the question of what -if any -are the finite-temperature signatures of these phases, especially in the currently experimentally relevant regime near or above the superexchange energy. We explore this question for thermodynamic observables by numerically calculating the thermodynamics of the SU(N ) FHM in the two-dimensional square lattice near densities of one particle per site, using determinant Quantum Monte Carlo and Numerical Linked Cluster Expansion. Interestingly, we find that for temperatures above the superexchange energy, where the correlation length is short, the energy, number of on-site pairs, and kinetic energy are universal functions of N . Although the physics in the regime studied is well beyond what can be captured by low-order high-temperature series, we show that an analytic description of the scaling is possible in terms of only one-and two-site calculations.

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“…In this work, we provide such a proposal by presenting an analysis of the dynamics of a strongly interacting few-body system of fermions with SU( N ) symmetry after a sudden change - a quench - in the trapping potential. Recently, systems of cold atoms in optical lattices with SU(3) and SU(4) symmetries have been explored theoretically 43,44 . The correlations of SU( N ) impenetrable systems have also been calculated for an increasing number of internal components and display interesting properties 45 .…”

Section: Introductionmentioning

confidence: 99%

Dynamics of spin and density fluctuations in strongly interacting few-body systems

Barfknecht¹,

Foerster²,

Zinner³

2019

Sci Rep

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The decoupling of spin and density dynamics is a remarkable feature of quantum one-dimensional many-body systems. In a few-body regime, however, little is known about this phenomenon. To address this problem, we study the time evolution of a small system of strongly interacting fermions after a sudden change in the trapping geometry. We show that, even at the few-body level, the excitation spectrum of this system presents separate signatures of spin and density dynamics. Moreover, we describe the effect of considering additional internal states with SU(N) symmetry, which ultimately leads to the vanishing of spin excitations in a completely balanced system.

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

Cited by 12 publications

References 42 publications

Suppression and revival of long-range ferromagnetic order in the multiorbital Fermi-Hubbard model

Suppression and revival of long-range ferromagnetic order in the multiorbital Fermi-Hubbard model

Universal thermodynamics of an SU($N$) Fermi-Hubbard Model

Dynamics of spin and density fluctuations in strongly interacting few-body systems

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