Finite-Energy Landau Liquid Theory for the 1D Hubbard Model: Pseudoparticle Energy Bands and Degree of Localization/Delocalization

This paper is part of a broader study whose main goal is the study of the finite-energy spectral properties of the non-perturbative one-dimensional (1D) Hubbard model and the evaluation of finite-energy correlation-function expressions. Here we study the deviations from the ground state values of double occupancy which result from creation or annihilation of holons, spinons, and pseudoparticles. The band-momentum dependence of the obtained double-occupancy spectra provides important information on the degree of localization/delocalization of the real-space lattice electron site distribution configurations associated with the pseudoparticles. We also study the band-momentum, on-site electronic repulsion, and electronic density dependence of the pseudoparticle energy bands. The shape of these bands plays an important role in the finite-energy spectral properties of the model. Such a shape defines the form of the lines in the momentum-energy/frequency plane where the peaks and edges of the one-electron and two-electron spectral weight of physical operators are located. Our findings are useful for the study of the one-electron and two-electron spectral weight distribution of physical operators.Comment: 24 pages, 9 figures. Accepted for publication in Physical Review

The TTF finite-energy spectral features in photoemission of TTF-TCNQ: The Hubbard-chain description

A dynamical theory which accounts for all microscopic one-electron processes is used to study the spectral function of the 1D Hubbard model for the whole $(k, \omega)$-plane, beyond previous studies which focused on the weight distribution in the vicinity of the singular branch lines only. While our predictions agree with those of the latter studies concerning the tetracyanoquinodimethane (TCNQ) related singular features in photoemission of the organic compound tetrathiafulvalene-tetracyanoquinodimethane (TTF-TCNQ) metallic phase, the generalized theory also leads to quantitative agreement concerning the tetrathiafulvalene (TTF) related finite-energy spectral features, which are found to correspond to a value of the on-site repulsion $U$ larger than for TCNQ. Our study reveals the microscopic mechanisms behind the unusual spectral features of TTF-TCNQ and provides a good overall description of those features for the whole $(k, \omega)$-plane.Comment: To appear in Journal of Physics: Condensed Matte

Spectral microscopic mechanisms and quantum phase transitions in a 1D correlated problem

In this paper we study the dominant microscopic processes that generate nearly the whole one-electron removal and addition spectral weight of the one-dimensional Hubbard model for all values of the on-site repulsion $U$. We find that for the doped Mott-Hubbard insulator there is a competition between the microscopic processes that generate the one-electron upper-Hubbard band spectral-weight distributions of the Mott-Hubbard insulating phase and finite-doping-concentration metallic phase, respectively. The spectral-weight distributions generated by the non-perturbative processes studied here are shown elsewhere to agree quantitatively for the whole momentum and energy bandwidth with the peak dispersions observed by angle-resolved photoelectron spectroscopy in quasi-one-dimensional compounds.Comment: 18 pages, 2 figure

One-Electron Singular Branch Lines of the Hubbard Chain

The momentum and energy dependence of the weight distribution in the vicinity of the one-electron spectral-function singular branch lines of the 1D Hubbard model is studied for all values of the electronic density and on-site repulsion $U$. To achieve this goal we use the recently introduced pseudofermion dynamical theory. Our predictions agree quantitatively for the whole momentum and energy bandwidth with the peak dispersions observed by angle-resolved photoelectron spectroscopy in the quasi-1D organic conductor TTF-TCNQ.Comment: Replaced with shortened version; 4 figure

Scattering mechanisms and spectral properties of the one-dimensional Hubbard model

It is found that the finite-energy spectral properties of the one-dimensional Hubbard model are controlled by the scattering of charged $\eta$-spin-zero $2\nu$-holon composite objects, spin-zero $2\nu$-spinon composite objects, and charged $\eta$-spin-less and spin-less objects, rather than by the scattering of independent $\eta$-spin 1/2 holons and spin 1/2 spinons. Here $\nu =1,2,...$. The corresponding $S$ matrix is calculated and its relation to the spectral properties is clarified.Comment: 8 pages, no figure

Effet antiparasitaire des graines de papaye (Carica papaya) chez l’aulacode (Thryonomys swinderianus Temminck, 1827) d’élevage : cas des aulacodicultures du Sud-Bénin

Des problèmes pathologiques sévissent souvent dans les élevages d’aulacodes (Thryonomys swinderianus) au Bénin. Des maladies parasitaires comme la coccidiose et les nématodoseses sont rencontréeschez l’aulacode. Au Bénin, cet animal d’élevage est surtout infesté par les coccidies, les trichures, les strongles et parfois les cestodes. En dehors de l’Amprol (3 g/kg) et du Ganidan (2 comprimés/jour pendant 3 jours peros), les éleveurs utilisent très fréquemment les graines de papaye sous forme séchée et broyée ou entière et fraîche comme vermifuge, bien que leur efficacité n’ait été testée scientifiquement. Le but de cette étude estd’évaluer les propriétés antiparasitaires des graines de papaye (Carica papaya) chez les aulacodes d’élevage afin d’établir sa posologie d’utilisation. La méthodologie d’étude est basée sur une enquête à l’aide d’un questionnaire et sur une analyse coprologique de 109 échantillons de fèces d’aulacodes par la méthode quantitative de Mac Master. Des résultats, il ressort que 88,99% des aulacodiculteurs utilisent la graine depapaye comme anthelminthique mais à des doses différentes (cuillerée à soupe, cuillerée à café, capsule de bière et petite boîte de tomate) et avec diverses pratiques (graines de papaye, papaye verte ou mature); 10,09%ont recours aux anthelminthiques vétérinaires et 0,92% utilisent diverses plantes médicinales (Crateva religiosa, Ocimum basilicum, Eucalyptus sp, Newbouldia laevis et Vernonia amygdalina) pour soigner les animaux. Les examens coprologiques montrent que les élevages sont infestés par les coccidies (72,73%) avec des OPG avoisinant 150.000, ensuite viennent les trichures et les strongles avec des taux respectifs de 36,36%et 9,09% et des OPG maxima respectifs de 1.200 et 600. L’examen des échantillons de matières fécales en station a montré une diminution de l’OPG de 425 à 0 avec l’utilisation du Benzal à la dose de 7,5 mg/kg de PV. L’utilisation de la graine de papaye à la dose de 100 mg/kg PV a permis d’obtenir une baisse considérable des OPG de plus de 75%