Phase diagram and pair Tomonaga-Luttinger liquid in a Bose-Hubbard model with flat bands

AbstractIn this paper we study a generalization of the Hubbard model by considering spin-spin interactions described by the exchange constant J. An external magnetic field his also taken into account. In the narrowband limit and for the 1D case, we present the exact solution obtained in the framework of the Green’s function formalism, using the Composite Operator Method. We report the T = 0 phase diagram for both ferro (J > 0) and anti-ferro (J < 0) couplings. The competition of the different energy scales (U, J, and h; being U the local charge interaction) generates a variety of phases and different charge and spin orderings.

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Application of the Landau-Luttinger Liquid Formulation to the Study of the Magnetic Properties of the 1-D Hubbard Model

International Journal of Modern Physics B ◽

10.1142/s021797929100002x ◽

1991 ◽

Vol 05 (01n02) ◽

pp. 3-30 ◽

Cited By ~ 3

Author(s):

J. Carmelo ◽

P. Horsch ◽

P.A. Bares ◽

A.A. Ovchinnikov

Keyword(s):

Magnetic Field ◽

Magnetic Properties ◽

Low Temperature ◽

Hubbard Model ◽

Luttinger Liquid ◽

Liquid Formulation ◽

One Dimensional ◽

Spin Excitations ◽

Arbitrary Strength ◽

The One

The Landau-Luttinger liquid formulation is used to investigate the physics of the one-dimensional Hubbard model in a magnetic field of arbitrary strength H. The low lying charge and spin excitations are studied. A novel branch of sound wave-like spin excitations arises for H>0. The low temperature thermodynamics is considered in some detail.

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Ground state phase diagram of the infinite dimensional Hubbard model: A variational study

Zeitschrift für Physik B Condensed Matter ◽

10.1007/bf01317359 ◽

1990 ◽

Vol 78 (1) ◽

pp. 69-80 ◽

Cited By ~ 57

Author(s):

P. Fazekas ◽

B. Menge ◽

E. M�ller-Hartmann

Keyword(s):

Phase Diagram ◽

Hubbard Model ◽

Ground State ◽

Ground State Phase Diagram ◽

Infinite Dimensional ◽

Variational Study

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Phase diagram of the half-filled 3D Hubbard model

Physical Review B ◽

10.1103/physrevb.39.4711 ◽

1989 ◽

Vol 39 (7) ◽

pp. 4711-4714 ◽

Cited By ~ 69

Author(s):

R. T. Scalettar ◽

D. J. Scalapino ◽

R. L. Sugar ◽

D. Toussaint

Keyword(s):

Phase Diagram ◽

Hubbard Model

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η-PAIRING SUPERCONDUCTIVITY IN THE NEGATIVE-U HUBBARD MODEL: EFFECT OF FLUCTUATIONS AND DISORDER

International Journal of Modern Physics B ◽

10.1142/s0217979294000841 ◽

1994 ◽

Vol 08 (15) ◽

pp. 2041-2058

Author(s):

JÜRGEN STEIN

Keyword(s):

Phase Diagram ◽

Asymptotic Expansion ◽

Hubbard Model ◽

Strong Coupling ◽

Mean Field ◽

Higher Order ◽

Field Phase ◽

Effective Pair ◽

The Mean ◽

Pair Hopping

We have studied the influence of singular fluctuations around the mean-field solution as well as higher order contributions to the geometry controlled asymptotic expansion of the propagators on η-pairing superconductivity in the strong coupling negative-U Hubbard model in the presence of unpaired electrons. The modifications of the mean-field results due to the introduction of disorder and allowance for finite U are also calculated. Besides the singularities already present in the O(2) nonlinear σ-model we find a filling-depending singular depression of the repulsive effective pair-hopping interaction which strongly alters the mean-field phase diagram and appears to suppress the η-pairing phase near the band edges.

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