Renormalization of the antisymmetric tensor field propagator and dynamical generation of the 1+−1^{+-} mesons in Resonance Chiral Theory

We discuss the renormalization of the $1^{--}$ vector meson propagator within Resonance chiral theory at one loop. Using the particular form of the interaction Lagrangian we show that additional poles of the renormalized propagator corresponding to $1^{+-}$ degrees of freedom can be generated. We give a concrete example of such an effect.Comment: 4 pages, 1 figure, to appear in Proceedings of the conference QCD 08, Montpellier, 7-12 July 200

Renormalization and additional degrees of freedom within the chiral effective theory for spin-1 resonances

We study in detail various aspects of the renormalization of the spin-1 resonance propagator in the effective field theory framework. First, we briefly review the formalisms for the description of spin-1 resonances in the path integral formulation with the stress on the issue of propagating degrees of freedom. Then we calculate the one-loop 1-- meson self-energy within the Resonance chiral theory in the chiral limit using different methods for the description of spin-one particles, namely the Proca field, antisymmetric tensor field and the first order formalisms. We discuss in detail technical aspects of the renormalization procedure which are inherent to the power-counting non-renormalizable theory and give a formal prescription for the organization of both the counterterms and one-particle irreducible graphs. We also construct the corresponding propagators and investigate their properties. We show that the additional poles corresponding to the additional one-particle states are generated by loop corrections, some of which are negative norm ghosts or tachyons. We count the number of such additional poles and briefly discuss their physical meaning.Comment: 65 pages, 12 figure

Quartett formation at (100)/(110)-interfaces of d-wave superconductors

Across a faceted (100)/(110) interface between two d-wave-superconductors the structure of the superconducting order parameter leads to an alternating sign of the local Josephson coupling. Describing the Cooper pair motion along and across the interface by a one-dimensional boson lattice model, we show that a small attractive interaction between the bosons boosts boson binding at the interface -- a phenomenon, which is intimately tied to the staggered sequence of 0- and Pi-junction contacts along the interface. We connect this finding to the recently observed h/4e oscillations in (100)/(110) SQUIDS of cuprate superconductors.Comment: 13 pages, 2 figure

Carlhintzeite, Ca2AlF7•H2O, from the Gigante granitic pegmatite, Córdoba province, Argentina: Description and crystal structure

Carlhintzeite, Ca2AlF7•H2O, has been found at the Gigante pegmatite, Punilla Department, Córdoba Province, Argentina. It occurs as colourless prismatic crystals up to 0.8 mm long, ubiquitously twinned on {001}. Electron microprobe analyses provided the empirical formula Ca1.98Al1.02F6.24(OH) 0.76•H1.62O. A crystal fragment used for the collection of structure data provided the triclinic, C1 cell: a = 9.4227(4), b = 6.9670(5), c = 9.2671(7) Å, α = 90.974(6), β = 104.802(5), γ = 90.026(6)°, V = 558.08(7) Å3 and Z = 4. The crystal structure, solved by direct methods and refined to R 1 = 0.0322 for 723 Fo > 4σF reflections, is made up of linkages of AlF6 octahedra, CaF8 polyhedra and CaF 6(H2O)2 polyhedra. The AlF6 octahedra are isolated from one another, but share polyhedral elements with Ca polyhedra. Most notably, the Al1 octahedron shares trans faces with two CaF 8 polyhedra and the Al2 octahedron shares trans edges with two CaF6(H2O)2 polyhedra. The linkage of the Ca polyhedra alone can be described as a framework in which edge-sharing chains along b are cross-linked by edge-sharing. Edge-sharing chains of Ca polyhedra along b in the carlhintzeite structure are similar to those along c in the structures of gearksutite, CaAlF4(OH)•(H2O), and prosopite, CaAl2F4(OH)4. © 2010 Mineralogical Society.Fil: Kampf, A. R.. Natural History Museum of Los Angeles County; Estados UnidosFil: Colombo, Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; ArgentinaFil: González Del Tánago, J.. Universidad Complutense de Madrid; Españ

Resonance saturation in the odd-intrinsic parity sector of low-energy QCD

Using the large N_C approximation we have constructed the most general chiral resonance Lagrangian in the odd-intrinsic parity sector that can generate low energy chiral constants up to O(p^6). Integrating out the resonance fields these O(p^6) constants are expressed in terms of resonance couplings and masses. The role of eta' is discussed and its contribution is explicitly factorized. Using the resonance basis we have also calculated two QCD Green functions of currents: and and found, imposing high energy constraints, additional relations for resonance couplings. We have studied several phenomenological implications based on these correlators from which let us mention here our prediction for the pi0-pole contribution to the muon g-2 factor: $a_\mu^{\pi^0} = 65.8(1.2)\times 10^{-11}$.Comment: 42 pages, 3 figure

Effects of spin fluctuations in the t-J model

Recent experiments on the Fermi surface and the electronic structure of the cuprate-supercondutors showed the importance of short range antiferromagnetic correlations for the physics in these systems. Theoretically, features like shadow bands were predicted and calculated mainly for the Hubbard model. In our approach we calculate an approximate selfenergy of the $t$-$J$ model. Solving the $U=\infty$ Hubbard model in the Dynamical Mean Field Theory (DMFT) yields a selfenergy that contains most of the local correlations as a starting point. Effects of the nearest neighbor spin interaction $J$ are then included in a heuristical manner. Formally like in $J$-perturbation theory all ring diagrams, with the single bubble assumed to be purely local, are summed to get a correction to the DMFT-self engergy This procedure causes new bands and can furnish strong deformation of quasiparticle bands. % Our results are finally compared with %former approaches to the Hubbard model.Comment: 3 Pages, Latex, 2 Postscript-Figures submitted to Physica

Disorder-Induced Static Antiferromagnetism in Cuprate Superconductors

Using model calculations of a disordered d-wave superconductor with on-site Hubbard repulsion, we show how dopant disorder can stabilize novel states with antiferromagnetic order. We find that the critical strength of correlations or impurity potential necessary to create an ordered magnetic state in the presence of finite disorder is reduced compared to that required to create a single isolated magnetic droplet. This may explain why in cuprates like LSCO low-energy probes have identified a static magnetic component which persists well into the superconducting state, whereas in cleaner systems like YBCO it is absent or minimal. Finally we address the case of nominally clean LSCO samples at optimal doping, where such ordered magnetic moments are absent, but where they can be induced by small concentrations of strong scatterers.Comment: 4 pages, 5 figure

Order parameter symmetries for magnetic and superconducting instabilities: Bethe-Salpeter analysis of functional renormalization-group solutions

The Bethe-Salpeter equation is combined with the temperature-cutoff functional renormalization group approach to analyze the order parameter structure for the leading instabilities of the 2D t-t' Hubbard model. We find significant deviations from pure s-, d-, or p-wave forms, which is due to the frustration of antiferromagnetism at small and intermediate t'. With adding a direct antiferromagnetic spin-exchange coupling the eigenfunctions in the particle-hole channel have extended s-wave form, while in the particle-particle singlet pairing channel a higher angular momentum component arises besides the standard d-wave symmetry, which flattens the angular dependence of the gap. For t' closer to 1/2 we find a delicate competition of ferromagnetism and triplet pairing with a nontrivial pair-wavefunction.Comment: 4 pages, 4 figures, RevTe