A Renormalization Group Analysis of Coupled Superconducting and Stripe Order in 1+1 Dimensions

In this paper we perform a renormalization group analysis on the 1+1 dimensional version of an effective field theory (previously proposed by Dung-Hai Lee, cond-mat/011393) describing (quantum) fluctuating stripe and superconductor orders. We find four possible phases corresponding to stripe order/disorder combined with superconducting order/disorder.Comment: 8 pages, 3 figures, revte

Meeting report: International symposium on the genetics of aging and life history II

The second International Symposium on the Genetics of Aging and Life History was held at the campus of Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, South Korea, from May 14 to 16, 2014. Many leading scientists in the field of aging research from all over the world contributed to the symposium by attending and presenting their recent work and thoughts. The aim of the symposium was to stimulate international collaborations and interactions among scientists who work on the biology of aging. In the symposium, the most recent and exciting work on aging research was presented, covering a wide range of topics, including the genetics of aging, age-associated diseases, and cellular senescence. The work was conducted in various organisms, including C. elegans, mice, plants, and humans. Topics covered in the symposium stimulated discussion of novel directions for future research on aging. The meeting ended with a commitment for the third International Symposium on the Genetics of Aging and Life History, which will be held in 2016. © Artan et al11sciescopu

Statins in the prevention and treatment of heart failure: a review of the evidence

Purpose of Review: We summarize the best evidence for statins in the prevention and treatment of heart failure. Recent Findings: In patients with cardiovascular risk factors or established atherosclerotic cardiovascular disease (but without heart failure), statins reduce the risk of incident heart failure—mainly by preventing myocardial infarction although an additional benefit from reducing myocardial ischemia cannot be excluded. However, in patients with established heart failure, statins do not reduce the risk of cardiovascular death, which is mainly caused by pump failure and ventricular arrhythmias. Retrospective analyses, however, suggest that statins may reduce the rate of heart failure hospitalization and atherosclerotic events (which are proportionately much less common in these patients than heart failure hospitalization or death). Summary: Statin therapy should probably be continued in patients with coronary artery disease developing heart failure, although the weak evidence and small benefit may not justify the use of this treatment in very elderly patients with a short life expectancy and in which polypharmacy is a problem

Critical behavior of the frustrated antiferromagnetic six-state clock model on a triangular lattice

We study the anti-ferromagnetic six-state clock model with nearest neighbor interactions on a triangular lattice with extensive Monte-Carlo simulations. We find clear indications of two phase transitions at two different temperatures: Below $T_I$ a chirality order sets in and by a thorough finite size scaling analysis of the specific heat and the chirality correlation length we show that this transition is in the Ising universality class (with a non-vanishing chirality order parameter below $T_I$). At $T_{KT}(<T_I)$ the spin-spin correlation length as well as the spin susceptibility diverges according to a Kosterlitz-Thouless (KT) form and spin correlations decay algebraically below $T_{KT}$. We compare our results to recent x-ray diffraction experiments on the orientational ordering of CF$_3$Br monolayers physisorbed on graphite. We argue that the six-state clock model describes the universal feature of the phase transition in the experimental system and that the orientational ordering belongs to the KT universality class.Comment: 8 pages, 9 figure

Properties of electrons near a Van Hove singularity

The Fermi surface of most hole-doped cuprates is close to a Van Hove singularity at the M point. A two-dimensional electronic system, whose Fermi surface is close to a Van Hove singularity shows a variety of weak coupling instabilities. It is a convenient model to study the interplay between antiferromagnetism and anisotropic superconductivity. The renormalization group approach is reviewed with emphasis on the underlying physical processes. General properties of the phase diagram and possible deformations of the Fermi surface due to the Van Hove proximity are described.Comment: Proceedings of SNS-01 to appear in the Journal of Physics and Chemistry of Solids, SNS-0

Critical Point Field Mixing in an Asymmetric Lattice Gas Model

The field mixing that manifests broken particle-hole symmetry is studied for a 2-D asymmetric lattice gas model having tunable field mixing properties. Monte Carlo simulations within the grand canonical ensemble are used to obtain the critical density distribution for different degrees of particle-hole asymmetry. Except in the special case when this asymmetry vanishes, the density distributions exhibit an antisymmetric correction to the limiting scale-invariant form. The presence of this correction reflects the mixing of the critical energy density into the ordering operator. Its functional form is found to be in excellent agreement with that predicted by the mixed-field finite-size-scaling theory of Bruce and Wilding. A computational procedure for measuring the significant field mixing parameter is also described, and its accuracy gauged by comparing the results with exact values obtained analytically.Comment: 10 Pages, LaTeX + 8 figures available from author on request, To appear in Z. Phys.

Resonantly damped surface and body MHD waves in a solar coronal slab with oblique propagation

The theory of magnetohydrodynamic (MHD) waves in solar coronal slabs in a zero-$\beta$ configuration and for parallel propagation of waves does not allow the existence of surface waves. When oblique propagation of perturbations is considered both surface and body waves are able to propagate. When the perpendicular wave number is larger than a certain value, the body kink mode becomes a surface wave. In addition, a sausage surface mode is found below the internal cut-off frequency. When non-uniformity in the equilibrium is included, surface and body modes are damped due to resonant absorption. In this paper, first, a normal-mode analysis is performed and the period, the damping rate, and the spatial structure of eigenfunctions are obtained. Then, the time-dependent problem is solved, and the conditions under which one or the other type of mode is excited are investigated.Comment: 19 pages, 9 figures, accepted for publication in Solar Physic

Photon and dilepton emission rates from high density quark matter

We compute the rates of real and virtual photon (dilepton) emission from dense QCD matter in the color-flavor locked (CFL) phase, focusing on results at moderate densities (3-5 times the nuclear saturation density) and temperatures $T\simeq80$ MeV. We pursue two approaches to evaluate the electromagnetic (e.m.) response of the CFL ground state: (i) a direct evaluation of the photon self energy using quark particle/-hole degrees of freedom, and (ii) a Hidden Local Symmetry (HLS) framework based on generalized mesonic excitations where the $\rho$ meson is introduced as a gauge boson of a local SU(3) color-flavor group. The $\rho$ coupling to generalized two-pion states induces a finite width and allows to address the issue of vector meson dominance (VMD) in the CFL phase. We compare the calculated emissivities (dilepton rates) to those arising from standard hadronic approaches including in-medium effects. For rather large superconducting gaps (several tens of MeV at moderate densities), as suggested by both perturbative and nonperturbative estimates, the dilepton rates from CFL quark matter turn out to be very similar to those obtained in hadronic many-body calculations, especially for invariant masses above $M\simeq0.3$ GeV. A similar observation holds for (real) photon production.Comment: 18 pages, 12 figure

Diffusive energy transport in the S=1 Haldane chain compound AgVP2S6

We present the results of measurements of the thermal conductivity $\kappa$ of the spin S=1 chain compound AgVP_2S_6 in the temperature range between 2 and 300 K and with the heat flow directed either along or perpendicular to the chain direction. The analysis of the anisotropy of the heat transport allowed for the identification of a small but non-negligible magnon contribution $\kappa_m$ along the chains, superimposed on the dominant phonon contribution $\kappa_ph$. At temperatures above about 100 K the energy diffusion constant D_E(T), calculated from the $\kappa_m(T)$ data, exhibits similar features as the spin diffusion constant D_S(T), previously measured by NMR. In this regime, the behaviour of both transport parameters is consistent with a diffusion process that is caused by interactions inherent to one-dimensional S=1 spin systems.Comment: 6 pages, 4 figure