4,787 research outputs found

    Correlated metallic state in honeycomb lattice: Orthogonal Dirac semimetal

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    A novel gapped metallic state coined orthogonal Dirac semimetal is proposed in the honeycomb lattice in terms of Z2Z_{2} slave-spin representation of Hubbard model. This state corresponds to the disordered phase of slave-spin and has the same thermaldynamical and transport properties as usual Dirac semimetal but its singe-particle excitation is gapped and has nontrivial topological order due to the Z2Z_{2} gauge structure. The quantum phase transition from this orthogonal Dirac semimetal to usual Dirac semimetal is described by a mean-field decoupling with complementary fluctuation analysis and its criticality falls into the universality class of 2+1D Ising model while a large anomalous dimension for the physical electron is found at quantum critical point (QCP), which could be considered as a fingerprint of our fractionalized theory when compared to other non-fractionalized approaches. As byproducts, a path integral formalism for the Z2Z_{2} slave-spin representation of Hubbard model is constructed and possible relations to other approaches and the sublattice pairing states, which has been argued to be a promising candidate for gapped spin liquid state found in the numerical simulation, are briefly discussed. Additionally, when spin-orbit coupling is considered, the instability of orthogonal Dirac semimetal to the fractionalized quantum spin Hall insulator (fractionalized topological insulator) is also expected. We hope the present work may be helpful for future studies in Z2Z_{2} slave-spin theory and related non-Fermi liquid phases in honeycomb lattice.Comment: 12 pages,no figures, more discussions added. arXiv admin note: text overlap with arXiv:1203.063

    Analysis of the BK2(1430),a2(1320),f2(1270)B \to K^*_2(1430), a_2(1320), f_2(1270) form-factors with light-cone QCD sum rules

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    In this article, we study the BK2(1430)B \to K^*_2(1430), a2(1320)a_2(1320), f2(1270)f_2(1270) form-factors with the light-cone QCD sum rules, where the BB-meson light-cone distribution amplitudes are used. In calculations, we observe that the line-shapes of the BB-meson light-cone distribution amplitude ϕ+(ω)\phi_+(\omega) have significant impacts on the values of the form-factors, and expect to obtain severe constraints on the parameters of the BB-meson light-cone distribution amplitudes from the experimental data in the future.Comment: 19 pages, 6 figures, slight revisio

    Analysis of the scalar doubly heavy tetraquark states with QCD sum rules

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    In this article, we perform a systematic study of the mass spectrum of the scalar doubly charmed and doubly bottom tetraquark states using the QCD sum rules.Comment: 17 pages, 24 figures, add more discussion

    Analysis of the vertices ρNN\rho NN, ρΣΣ\rho\Sigma\Sigma and ρΞΞ\rho\Xi\Xi with light-cone QCD sum rules

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    In this article, we calculate the strong coupling constants of the ρNN\rho NN, ρΣΣ\rho\Sigma\Sigma and ρΞΞ\rho\Xi\Xi in the framework of the light-cone QCD sum rules approach. The strong coupling constants of the meson-baryon-baryon are the fundamental parameters in the one-boson exchange model which describes the baryon-baryon interactions successfully. The numerical values are in agreement with the existing calculations in part. The electric and magnetic F/(F+D)F/(F+D) ratios deviate from the prediction of the vector meson dominance theory, the SU(3) symmetry breaking effects are very large.Comment: 19 pages, 6 figures, revised version, add more discussions(Correct writing errors

    Thermodynamic Properties of Block Copolymer Electrolytes Containing Imidazolium and Lithium Salts

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    We report on the thermal properties, phase behavior, and thermodynamics of a series of polystyrene-block-poly(ethylene oxide) copolymers (SEO) mixed with the ionic species Li[N(SO_(2)CF_3)_2] (LiTFSI), imidazolium TFSI (ImTFSI), and an equimolar mixture of LiTFSI and ImTFSI (Mix). Differential scanning calorimetric scans reveal similar thermal behavior of SEO/LiTFSI and SEO/ImTFSI at the same salt concentrations. Phase behavior and thermodynamics were determined using a combination of small-angle X-ray scattering and birefringence. The thermodynamics of our mixtures can be mapped on to the theory of neat block copolymer phase behavior provided the Flory−Huggins interaction parameter, χ, between the blocks is replaced by an effective χ (χ_(eff)) that increases linearly with salt concentration. The phase behavior and the value of m, the slope of the χ_(eff) versus salt concentration data, were similar for SEO/LiTFSI, SEO/ImTFSI, and SEO/Mix blends. The theory developed by Wang [ J. Phys. Chem. B. 2008, 41, 16205] provides a basis for understanding the fundamental underpinnings of the measured value of m. We compare our experimental results with the predictions of this theory with no adjustable parameters

    Effect of atmospheric turbulence on propagation properties of optical vortices formed by using coherent laser beam arrays

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    In this paper, we consider the effect of the atmospheric turbulence on the propagation of optical vertex formed from the radial coherent laser beam array, with the initially well-defined phase distribution. The propagation formula of the radial coherent laser array passing through the turbulent atmosphere is analytically derived by using the extended Huygens-Fresnel diffraction integral. Based on the derived formula, the effect of the atmospheric turbulence on the propagation properties of such laser arrays has been studied in great detail. Our main results show that the atmospheric turbulence may result in the prohibition of the formation of the optical vortex or the disappearance of the formed optical vortex, which are very different from that in the free space. The formed optical vortex with the higher topological charge may propagate over a much longer distance in the moderate or weak turbulent atmosphere. After the sufficient long-distance atmospheric propagation, all the output beams (even with initially different phase distributions) finally lose the vortex property and gradually become the Gaussian-shaped beams, and in this case the output beams actually become incoherent light fields due to the decoherence effect of the turbulent atmosphere.Comment: 10 pages, 5 figure
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