Technicolor corrections on<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi>B</mml:mi></mml:mrow><mml:mrow><mml:mi>s</mml:mi><mml:mo>,</mml:mo><mml:mi>d</mml:mi></mml:mrow></mml:msub></mml:mrow><mml:mo>→</mml:mo><mml:mi>γ</mml:mi><mml:mi>γ</mml:mi></mml:math>decays in QCD factorization

Xiao, Z. J.; Lu, C.; Huo, Wu-Jun

doi:10.1103/physrevd.67.094021

Cited by 19 publications

(12 citation statements)

References 62 publications

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“…First we consider a square variation of the Kagome lattice which is known to exhibit a flat band touching quadratically a dispersive band. 23 Under appropriate variation of hopping parameters, we find that a pair of Dirac points between the two lower bands emerges from the Γ point and merges at another TRIM, with a semi-Dirac spectrum preceding the opening of a gap, see Fig. 5.…”

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confidence: 74%

Winding Vector: How to Annihilate Two Dirac Points with the Same Charge

et al. 2018

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The merging or emergence of a pair of Dirac points may be classified according to whether the winding numbers which characterize them are opposite (+− scenario) or identical (++ scenario). From the touching point between two parabolic bands (one of them can be flat), two Dirac points with the same winding number emerge under appropriate distortion (interaction, etc), following the ++ scenario. Under further distortion, these Dirac points merge following the +− scenario, that is corresponding to opposite winding numbers. This apparent contradiction is solved by the fact that the winding number is actually defined around a unit vector on the Bloch sphere and that this vector rotates during the motion of the Dirac points. This is shown here within the simplest two-band lattice model (Mielke) exhibiting a flat band. We argue on several examples that the evolution between the two scenarios is general.PACS numbers:

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confidence: 74%

Winding Vector: How to Annihilate Two Dirac Points with the Same Charge

et al. 2018

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“…1. Type III has been discussed recently [9][10][11] in hexagonal and kagome lattices without magnetic flux, and it was found that in this case the zero gap is protected by topological arguments 9 . Type III has been also shown to exhibit a topological insulator phase in the presence of spin-orbit interactions 12 .…”

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confidence: 99%

Isolated flat bands and spin-1 conical bands in two-dimensional lattices

2010

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Dispersionless bands, such as Landau levels, serve as a good starting point for obtaining interesting correlated states when interactions are added. With this motivation in mind, we study a variety of dispersionless ("flat") band structures that arise in tight-binding Hamiltonians defined on hexagonal and kagome lattices with staggered fluxes. The flat bands and their neighboring dispersing bands have several notable features: (a) flat bands can be isolated from other bands by breaking time-reversal symmetry, allowing for an extensive degeneracy when these bands are partially filled; (b) an isolated flat band corresponds to a critical point between regimes where the band is electron-like or hole-like, with an anomalous Hall conductance that changes sign across the transition; (c) when the gap between a flat band and two neighboring bands closes, the system is described by a single spin-1 conical-like spectrum, extending to higher angular momentum the spin-1/2 Dirac-like spectra in topological insulators and graphene; (d) some configurations of parameters admit two isolated parallel flat bands, raising the possibility of exotic "heavy excitons" and (e) we find that the Chern number of the flat bands, in all instances that we study here, is zero.

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“…They have been studied since the 1970s in amorphous semiconductors [2][3][4], and understood using projection operators [5]. More recently they have been studied on kagome, honeycomb, and square lattices [6][7][8][9][10][11]. In Ref.[10] flatbands were isolated by gaps, and the question of whether it is possible to have a flatband with nonzero Chern number was raised.…”

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Fractional Quantum Hall States at Zero Magnetic Field

et al. 2011

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We present a simple prescription to flatten isolated Bloch bands with a nonzero Chern number. We first show that approximate flattening of bands with a nonzero Chern number is possible by tuning ratios of nearest-neighbor and next-nearest-neighbor hoppings in the Haldane model and, similarly, in the chiral-π-flux square lattice model. Then we show that perfect flattening can be attained with further range hoppings that decrease exponentially with distance. Finally, we add interactions to the model and present exact diagonalization results for a small system at 1/3 filling that support (i) the existence of a spectral gap, (ii) that the ground state is a topological state, and (iii) that the Hall conductance is quantized.

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Technicolor corrections onBs,d→γγdecays in QCD factorization

Cited by 19 publications

References 62 publications

Winding Vector: How to Annihilate Two Dirac Points with the Same Charge

Winding Vector: How to Annihilate Two Dirac Points with the Same Charge

Isolated flat bands and spin-1 conical bands in two-dimensional lattices

Fractional Quantum Hall States at Zero Magnetic Field

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