Nonuniversal spectral properties of the Luttinger model

The one electron spectral functions for the Luttinger model are discussed for large but finite systems. The methods presented allow a simple interpretation of the results. For finite range interactions interesting nonunivesal spectral features emerge for momenta which differ from the Fermi points by the order of the inverse interaction range or more. For a simplified model with interactions only within the branches of right and left moving electrons analytical expressions for the spectral function are presented which allows to perform the thermodynamic limit. As in the general spinless model and the model including spin for which we present mainly numerical results the spectral functions do not approach the noninteracting limit for large momenta. The implication of our results for recent high resolution photoemission measurements on quasi one-dimensional conductors are discussed.Comment: 19 pages, Revtex 2.0, 5 ps-figures, to be mailed on reques

A new interpretation of Bethe ansatz solutions for massive Thirring model

We reexamine Bethe ansatz solutions of the massive Thirring model. We solve equations of periodic boundary conditions numerically without referring to the density of states. It is found that there is only one bound state in the massive Thirring model. The bound state spectrum obtained here is consistent with Fujita-Ogura's solutions of the infinite momentum frame prescription. Further, it turns out that there exist no solutions for string-like configurations. Instead, we find boson boson scattering states in 2-particle 2-hole configurations where all the rapidity variables turn out to be real.Comment: 36 pages, Latex, no figure

Spin-density wave versus superconducting fluctuations for quasi-one-dimensional electrons in two chains of Tomonaga-Luttinger liquids

We study possible states at low temperatures by applying the renormalization-group method to two chains of Tomonaga-Luttinger liquids with both repulsive intrachain interactions and interchain hopping. As the energy decreases below the hopping energy, three distinct regions I, III, and II appear successively depending on properties of fluctuations. The crossover from the spin-density wave (SDW) state to superconducting (SC) state takes place in region III where there are the excitation gaps of transverse charge and spin fluctuations. The competition between SDW and SC states in region III is crucial to understanding the phase diagram in the quasi-one-dimensional organic conductors.Comment: 11 pages, Revtex format, 1 figure, to be published in Phys. Rev.

Association between Helicobacter pylori infection and inflammatory bowel disease: A meta-analysis and systematic review of the literature

Background: Epidemiologic data suggest a protective effect of Helicobacter pylori infection against the development of autoimmune disease. Laboratory data illustrate H. pylori 's ability to induce immune tolerance and limit inflammatory responses. Numerous observational studies have investigated the association between H. pylori infection and inflammatory bowel disease (IBD). Our aim was to perform a systematic review and meta-analysis of this association. Methods: Medline, EMBASE, bibliographies, and meeting abstracts were searched by 2 independent reviewers. Of 369 abstracts reviewed, 30 promising articles were reviewed in detail. Twenty-three studies met our inclusion criteria (subject N = 5903). Meta-analysis was performed with the metan command in Stata 10.1. Results: Overall, 27.1% of IBD patients had evidence of infection with H. pylori compared to 40.9% of patients in the control group. The estimated relative risk of H. pylori infection in IBD patients was 0.64 (95% confidence interval [CI]: 0.54–0.75). There was significant heterogeneity in the included studies that could not be accounted for by the method of IBD and H. pylori diagnosis, study location, or study population age. Conclusions: These results suggest a protective benefit of H. pylori infection against the development of IBD. Heterogeneity among studies and the possibility of publication bias limit the certainty of this finding. Further studies investigating the effect of eradication of H. pylori on the development of IBD are warranted. Because environmental hygiene and intestinal microbiota may be strong confounders, further mechanistic studies in H. pylori mouse models are also necessary to further define the mechanism of this negative association. (Inflamm Bowel Dis 2009;)Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75792/1/21116_ftp.pd

Spatial coherence measurements of a 13.2 nm transient Nickel-like Cadmium soft x-ray laser pumped at grazing incidence

Includes bibliographical references (pages [12872-12873]).The spatial coherence of a 13.2 nm transient collisional Ni-like Cd soft X-ray laser pumped at 23 degrees grazing incidence was measured in a series of Young's double-slit experiments. We observed pronounced fringe visibility variations associated with microstructures in the beam's intensity profile. The transverse coherence length was measured to be about 1/20 of the beam diameter and did not significantly improve with longer plasma columns. The equivalent incoherent source size is determined to be 10 μm and the laser's peak spectral brightness ~ 3 × 1023 photons/sec/mm2/mrad2 within less than 0.01% spectral bandwidth

Monte Carlo Simulations of Conformal Theory Predictions for the 3-state Potts and Ising Models

The critical properties of the 2D Ising and 3-state Potts models are investigated using Monte Carlo simulations. Special interest is given to measurement of 3-point correlation functions and associated universal objects, i.e. structure constants. The results agree well with predictions coming from conformal field theory confirming, for these examples, the correctness of the Coulomb gas formalism and the bootstrap method.Comment: 11 pages, 6 Postscript figures, uses Revte

Capillary discharge-driven metal vapor plasma waveguides

Includes bibliographical references (pages 026413-6).We report the generation of dense plasma waveguides containing a large concentration of silver ions by means of a fast (~55 ns first half-cycle) microcapillary discharge. Concave plasma density profiles with axial electron density >1×1019 cm−3 were measured from discharge ablation of 330 or 440 μm diameter Ag2S capillaries with 3-5 kA peak amplitude current pulses. The dynamic of this plasma waveguide was studied with interferometry, absorption measurements, and hydrodynamic model simulations. The results are relevant to the development of efficient longitudinally pumped metal vapor soft x-ray lasers, in particular those employing transient excitation of Ni-like ions. An approach to the design of a gain saturated waveguided 13.9 nm laser in Ni-like Ag is discussed

Saturated 13.2 nm high-repetition-rate laser in nickel-like cadmium

Includes bibliographical references (page 2583).We report gain-saturated operation of a 13.2 nm tabletop laser in Ni-like Cd at a 5 Hz repetition rate. A gain-length product G×L=17.6 was obtained by heating a precreated plasma with 8 ps duration Ti:sapphirelaser pulses with an energy of only 1 J impinging at a grazing angle of 23°. With an average power of ~1 mW, this laser is an attractive coherent source for at-wavelength metrology of extreme UV lithography optics and other applications