December 2005 arXiv papers — page 16

Leroux Philippe

The aim of this paper is to further explore an idea from J.-L. Loday briefly exposed in [5]. We impose a natural and simple symmetry on a unit action over the most general quadratic relation which can be written. This leads us to two families of binary, quadratic and regular operads whose free objects, as well as their duals in the sense of Ginzburg and Kapr

Manuel Bodirsky, Omer Gimenez, Mihyun Kang, Marc Noy

We show that the number $g_n$ of labelled series-parallel graphs on $n$ vertices is asymptotically $g_n \sim g\cdot n^{-5/2} γ^n n!$, where $γ$ and $g$ are explicit computable constants. We show that the number of edges in random series-parallel graphs is asymptotically normal with linear mean and variance, and that the number of edges is sharply concentrate

Yusif S. Gasimov

Different practical problems, espesially, problems of hydrodynamics, elasticity theory, geophysics and aerodynamics can be reduced to finding of an optimal shape. The investigation of these problems is based on the study of depending domain of the functiuonals their first variation and gradient. In the paper the inverse problem relatively domain is considere

Yacin Ameur, Michael Cwikel

We prove new estimates of the $K$-divisibility constants for some special Banach couples. In particular, we prove that the $K$-divisibility constant for a couple of the form $(U\oplus V, U)$ where $U$ and $V$ are non-trivial Hilbert spaces equals $2/\sqrt{3}$. We also prove estimates for the $K$-divisibility constant of the two-dimensional version of the cou

R. Guralnick, G Roehrle

The goal of this note is to classify the weakly closed unipotent subgroups in the split Chevalley groups. In an application we show under some mild assumptions on the characteristic that the Lie algebra of a connected simple algebraic group fails to be a so called 2F-module.

Izu Vaisman

We recall the presentation of the generalized, complex structures by classical tensor fields, while noticing that one has a similar presentation and the same integrability conditions for generalized, paracomplex and subtangent structures. This presentation shows that the generalized, complex, paracomplex and subtangent structures belong to the realm of Poiss

Gerd Grubb

In a recent work, Paycha and Scott establish formulas for all the Laurent coefficients of Tr(AP^{-s}) at the possible poles. In particular, they show a formula for the zero'th coefficient at s=0, in terms of two functions generalizing, respectively, the Kontsevich-Vishik canonical trace density, and the Wodzicki-Guillemin noncommutative residue density o

Gerd Grubb

Classical pseudodifferential operators A on closed manifolds are considered. It is shown that the basic properties of the canonical trace TR A introduced by Kontsevich and Vishik are easily proved by identifying it with the leading nonlocal coefficient C_0(A,P) in the trace expansion of A(P-λ)^{-N} (with an auxiliary elliptic operator P), as determined in a

Yuri Safarov

We study the relation between the spectrum of a self-adjoint operator and its multidimensional numerical range. It turns out that the multidimensional numerical range is a convex set whose extreme points are sequences of eigenvalues of the operator. Every collection of eigenvalues which can be obtained by the Rayleigh--Ritz formula generates an extreme point

A. Liam Fitzpatrick, Lisa Randall

It was recently proposed that our universe could naturally come to be dominated by 3-branes and 7-branes if the universe is ten-dimensional. In this paper, we explicitly demonstrate that gravity can be localized on the intersection of three 7-branes in AdS10 to give four-dimensional gravity. We derive the exact relations among the tensions of the branes, and

M. Aganagic, D. Jafferis, N. Saulina

We develop means of computing exact degerenacies of BPS black holes on toric Calabi-Yau manifolds. We show that the gauge theory on the D4 branes wrapping ample divisors reduces to 2D q-deformed Yang-Mills theory on necklaces of P^1's. As explicit examples we consider local P^2, P^1 x P^1 and A_k type ALE space times C. At large N the D-brane partition f

Dah-Wei Chiou, Ori J. Ganor, Bom Soo Kim

Super twistor space admits a certain (super) complex structure deformation that preserves the Poincare subgroup of the symmetry group PSL(4|4) and depends on 10 parameters. In a previous paper [hep-th/0502076], it was proposed that in twistor string theory this deformation corresponds to augmenting N=4 super Yang-Mills theory by a mass term for the left-chir

Agostino Butti, Alberto Zaffaroni

AdS/CFT predicts a precise relation between the central charge a, the scaling dimensions of some operators in the CFT on D3-branes at conical singularities and the volumes of the horizon and of certain cycles in the supergravity dual. We review how a quantitative check of this relation can be performed for all toric singularities. In addition to the results

A. E. Shabad, V. V. Usov

\\The Bethe-Salpeter equation in a strong magnetic field is studied for positronium atom in an ultra-relativistic regime, and a (hypercritical) value for the magnetic field is determined, which provides the full compensation of the positronium rest mass by the binding energy in the maximum symmetry state. The compensation becomes possible owing to the fallin

Bin Zhou, Han-Ying Guo

We describe how conformal Minkowski, dS- and AdS-spaces can be united into a single submanifold [N] of RP^5. It is the set of generators of the null cone in M^{2,4}. Conformal transformations on the Mink-, dS- and AdS-spaces are induced by O(2,4) linear transformations on M^{2,4}. We also describe how Weyl transformations and conformal transformations can be

Hiroyuki Abe, Tetsutaro Higaki, Tatsuo Kobayashi

We study supersymmetric models with double gaugino condensations in the hidden sector, where the gauge couplings depend on two light moduli of superstring theory. We perform a detailed analysis of this class of model and show that there is no stable supersymmetric minimum with finite vacuum values of moduli fields. Instead, we find that the supersymmetry bre

S. L. Lebedev

The effect of radiation polarization attended with the motion of spinning charge in the magnetic field could be viewed through the classical theory of self-interaction. The quantum expression for the polarization time follows from the semiclassical relation $T_{QED}\sim \hbar c^{3}/μ_{B}^2ω_{c}^3$, and needs quantum explanation neither for the orbit nor for

Jun Saito

A superspace formulation using superconnections and supercurvatures is specifically constructed for N=4 extended super Yang-Mills theory with a central charge in four dimensions, first proposed by Sohnius, Stelle and West long ago. We find that the constraints, almost uniquely derived from the possible spin structure of the multiplet, can be algebraically so

S. G. Kamath

The familiar trace identity associated with the scale transformation xxxx on the Lagrangian density for a noninteracting massive real scalar field in 2 + 1 dimensions is shown to be violated on a single plate on which the Dirichlet boundary condition xxxx is imposed.It is however respected in : i. 1 + 1 dimensions in both free space and on a single plate on

Andrew J. Tolley, C. P. Burgess, D. Hoover, Y. Aghababaie

We study a general configuration of parallel branes having co-dimension >2 situated inside a compact d-dimensional bulk space within the framework of a scalar and flux field coupled to gravity in D dimensions, such as arises in the bosonic part of some D-dimensional supergravities. A general relation is derived which relates the induced curvature of the obse

David Tong

These lectures cover aspects of solitons with focus on applications to the quantum dynamics of supersymmetric gauge theories and string theory. The lectures consist of four sections, each dealing with a different soliton. We start with instantons and work down in co-dimension to monopoles, vortices and, eventually, domain walls. Emphasis is placed on the mod

Marcin Ostrowski

In this paper we examine the Casimir effect for charged fields in presence of external magnetic field. We consider scalar field (connected with spinless particles) and the Dirac field (connected with 1/2-spin particles). In both cases we describe quantum field using the canonical formalism. We obtain vacuum energy by direct solving field equations and using

E. Accomando, K. Benakli

We give a brief review of some aspects of physics with TeV size extra-dimensions. We focus on a minimal model with matter localized at the boundaries for the study of the production of Kaluza-Klein excitations of gauge bosons. We briefly discuss different ways to depart from this simple analysis.

Yu. A. Simonov

Spin-dependent deconfined interaction in the Q\barQ system is derived from the field correlators known from lattice and analytic calculations. As a result hyperfine splitting is found numerically for charmonium, bottomonium and strangeonium in the range T_c<T<2T_c. Spin-orbit interaction due to magnetic correlators (the Thomas term) is able to produce numero

I. F. Ginzburg

The earlier history of two--photon physics is reviewed.

M. M. Muhlleitner

The various search modes for the Higgs bosons of the Standard Model (SM) and its Minimal Supersymmetric Extension (MSSM) at the International Linear Collider (ILC) will be summarized briefly. In particular, as a unique discovery mode the production of heavy neutral MSSM Higgs bosons for medium values of $\tanβ$ in photon collisions will be presented. Further

Thorsten Ewerth

Recently, we studied the branching ratios of rare K and B decays in models with Minimal Flavor Violation (MFV) using the presently available information from the universal unitarity triangle analysis and from the measurements of Br(B -> Xs gamma), Br(B -> Xs l+l-) and Br(K+ -> pi+ nu nubar). We analyzed in detail possible scenarios with positive or negative

A M. Cooper-Sarkar

W and Z production at the LHC occur at small Bjorken x, and are thus subject to the theoretical uncertainties of low-x physics. The implications of this for the PDF uncertainties on W and Z production are discussed, including the limitations this puts on their usefulness as luminosity monitors. The possibility of using LHC measurements to improve PDF uncerta

Harmen J. Warringa

We present results of the calculation of phase diagrams of the three-flavor NJL model as a function of temperature and different quark chemical potentials. These phase diagrams are an extension of earlier calculations in the literature in which either only the possibility of color superconductivity or the possibility of pseudoscalar condensation was investig

B. Blok, L. Frankfurt

We investigate the effective field theory (EFT) which gives the approximate description of the scattering of the two hard small dipoles in the small $x$ processes in QCD near the black disc limit(BDL). We argue that the perturbative QCD approaches predict the existence of tachyon and visualize it in the approximation where $α&#39;_P=0$ . We demonstrate that

Gino N. J. Ananos

We study the behavior of the renormalized sextic coupling at the intermediate and strong coupling regime for the $ϕ^4 $ theory defined in $d=2$-dimension. We found a good agreement with the results obtained by the field-theoretical renormalization-group in the Ising limit. In this work we use the lattice regularization method.

Shan-Huei Chuang

We reviewed CDF and D0 searches for R-parity violation supersymmetry in leptons involved final states using up to 344+-21 pb-1 Tevatron Run II data of ppbar collisions at sqrt{s} = 1.96 TeV. All the results were in good agreement with the standard model expectations. No evidence of new physics was observed. However, owing to the improvement on detectors, ene

Sijbrand de Jong

The Electroweak sector of the Standard Model is reviewed and best fits are presented for its free parameters based on currently available experimental tests. The Standard Model remains an excellent descriptions of the available experimental data. The preferred mass range of the still elusive Higgs boson in the Standard Model is $114<m_{\mathrm{H}}<219$ GeV a

Johannes Haller

In this article the potential of the ATLAS experiment to discover MSSM Higgs bosons is discussed. Various Monte-Carlo studies for SM Higgs boson production and dedicated MSSM Higgs boson analyses are taken into account to investigate the discovery potential in four different CP-conserving MSSM benchmark scenarios, the Mh-max scenario, the no mixing scenario,

Peter Diener, Frank Herrmann, Denis Pollney, Erik Schnetter

We present a detailed analysis of binary black hole evolutions in the last orbit, and demonstrate consistent and convergent results for the trajectories of the individual bodies. The gauge choice can significantly affect the overall accuracy of the evolution. It is possible to reconcile certain gauge dependent discrepancies by examining the convergence limit

Orhan Donmez

In this paper, we have solved 1D special relativistic hydrodynamical equations using different numerical method in computational gas dynamics. The numerical solutions of these equations for smooth wave cases give better solution when we use $Non-TVD$(Total Variable Diminishing) but solution of discontinuity wave produces some oscillation behind the shock. On

Lorenzo Iorio

In addition to the pericentre ω, the mean anomaly M and, thus, the mean longitude λ, also the orbital period Pb and the mean motion $n$ of a test particle are modified by the Dvali-Gabadadze-Porrati gravity. While the correction to Pb depends on the mass of the central body and on the geometrical features of the orbital motion around it, the correction to $n

P. Kraikivski, R. Lipowsky, J. Kierfeld

We study the activated motion of adsorbed polymers which are driven over a structured substrate by a localized point force.Our theory applies to experiments with single polymers using, for example, tips of scanning force microscopes to drag the polymer.We consider both flexible and semiflexible polymers,and the lateral surface structure is represented by dou

Evgeny B. Stukalin, Anatoly B. Kolomeisky

General discrete one-dimensional stochastic models to describe the transport of single molecules along coupled parallel lattices with period $N$ are developed. Theoretical analysis that allows to calculate explicitly the steady-state dynamic properties of single molecules, such as mean velocity $V$ and dispersion $D$, is presented for N=1 and N=2 models. For

Sandro Wimberger, Peter Schlagheck, Riccardo Mannella

We present a method to numerically compute accurate tunnelling rates for a Bose-Einstein condensate which is described by the nonlinear Gross-Pitaevskii equation. Our method is based on a sophisticated real-time integration of the complex-scaled Gross-Pitaevskii equation, and it is capable of finding the stationary eigenvalues for the Wannier-Stark problem.

M. A. Zudov, R. R. Du, L. N. Pfeiffer, K. W. West

We extend our studies of microwave photoresistance of ultra-high mobility two-dimensional electron system (2DES) into the high-intensity, non-linear regime employing both monochromatic and bichromatic radiation. Under high-intensity monochromatic radiation $ω$ we observe new zero-resistance states (ZRS) which correspond to rational values of $ε=ω/ω_C$ ($ω_C$

A. Yahalom, R. Englman

The evolution of open systems, subject to both Hamiltonian and dissipative forces, is studied by writing the $nm$ element of the time ($t$) dependent density matrix in the form \ber ρ_{nm}(t)&=& \frac {1}{A} \sum_{α=1}^A γ^α_n (t)γ^{α*}_m (t) \enr The so called &#34;square root factors&#34;, the $γ(t)$&#39;s, are non-square matrices and are averaged over $A$

X. F. Wang, Tapash Chakraborty

Quantun spin transport through a short DNA chain connected to ferromagnetic electrodes has been investigated by the transfer matrix method. We describe the system by a tight-binding model where the parameters are extracted from the experimental data and realistic metal energy bands. For ferromagnetic iron electrodes, the magnetoresistance of a 30-basepair Po

Xianwei Sha, R. E. Cohen

We compute the lattice-dynamical and thermal equation of state properties of ferromagnetic bcc iron using the first principles linear response linear-muffin-tin-orbital method in the generalized-gradient approximation. The calculated phonon dispersion and phonon density of states, both at ambient and high pressures, show good agreement with inelastic neutron

J. Shumway

We present a computer simulation of exciton-exciton scattering in a quantum well. Specifically, we use quantum Monte Carlo techniques to study the bound and continuum states of two excitons in a 10 nm wide GaAs/Al$_{0.3}$Ga$_{0.7}$As quantum well. From these bound and continuum states we extract the momentum-dependent phase shifts for s-wave scattering. A su

P. Coleman

Over the past decades, research into strongly correlated electron materials that has consistently outperformed our wildest expectations, with new discoveries and radically new theoretical insights. SCES &#39;05 reaffirmed this vitality. Highlight areas included parity violating superconductivity, a new, two dimensional Helium-3 ``Kondo lattice&#39;&#39; and

M. Daghofer, W. Koller, A. Pruell, H. G. Evertz

Effective models are derived from the ferromagnetic Kondo lattice model with classical corespins, which greatly reduce the numerical effort. Results for these models are presented. They indicate that double exchange gives the correct order of magnitude and the correct doping dependence of the Curie temperature. Furthermore, we find that the jump in the parti

V. Blickle, T. Speck, L. Helden, U. Seifert

We study the motion of an overdamped colloidal particle in a time-dependent non-harmonic potential. We demonstrate the first law-like balance between applied work, exchanged heat, and internal energy on the level of a single trajectory. The observed distribution of applied work is distinctly non-Gaussian in good agreement with numerical calculations. Both th

M. L. Chiofalo, S. Giorgini, M. Holland

We develop a time-dependent mean-field theory to investigate the released momentum distribution and the released energy of an ultracold Fermi gas in the BCS-BEC crossover after the scattering length has been set to zero by a fast magnetic-field ramp. For a homogeneous gas we analyze the non-equilibrium dynamics of the system as a function of the interaction

Benjamin Morgan, D. M. Broun, Ruixing Liang, D. A. Bonn

Measurements of the DC resistivity of under-doped cuprate superconductors have revealed a metal--insulator transition at low temperatures when superconductivity is suppressed by a very large magnetic field, with the resistivity growing logarithmically in the low temperature limit. This insulating behaviour has been associated not only with the large magnetic

Alexander Khaetskii

We have described the electron spin dynamics in the presence of Rashba spin- orbit interaction and disorder using the spin-density matrix method. We showed that in the Born approximation in the scattering amplitude the spin current is zero for an arbitrary ratio of the spin-orbit splitting and the scattering rate and for an arbitrary disorder potential. We a

Jean-Michel Mignot, Masafumi Sera, Fumitoshi Iga

Low-temperature, high-field (H[-110] <= 7.5 T), neutron diffraction experiments on single-crystal Ce0.70Pr0.30B6 are reported. Two successive incommensurate phases are found to exist in zero field. The appearance, for H >= 4.6 T at T = 2 K, of an antiferromagnetic structure, k{AF} = (1/2, 1/2, 1/2), most likely due to an underlying antiferroquadrupolar order

Yves Garrabos, Fabien Palencia, Carole Lecoutre-Chabot, Erkey Can John

We present the master (i.e. unique) behavior of the correlation length, as a function of the thermal field along the critical isochore, asymptotically close to the gas-liquid critical point of xenon, krypton, argon, helium 3, sulfur hexafluoride, carbon dioxide and heavy water. It is remarkable that this unicity extends to the correction-to-scaling terms. Th

M. V. Kartsovnik, D. Andres, S. V. Simonov, W. Biberacher

We present comparative studies of the orientation effect of a strong magnetic field on the interlayer resistance of $α$-(BEDT-TTF)$_2$KHg(SCN)$_4$ samples characterized by different crystal quality. We find striking differences in their behavior which is attributed to the breakdown of the coherent charge transport across the layers in the lower quality sampl

O. Waldmann, G. Carver, C. Dobe, D. Biner

Time-resolved inelastic neutron scattering measurements on an array of single-crystals of the single-molecule magnet Mn12ac are presented. The data facilitate a spectroscopic investigation of the slow relaxation of the magnetization in this compound in the time domain.

W. Apel, Yu. A. Bychkov, M. Weyrauch

We analyse theoretically the conductivity of a quantum Hall system exposed to microwave radiation. We find that whenever microwave frequency and cyclotron frequency are commensurate, there is a {\em resonance} in the longitudinal conductivity. This resonance has the form of the derivative of a Lorentz function; precisely at the center of the resonance, the m

Michael Schmiedeberg, Holger Stark

We investigate particle transport in the honeycomb billiard that consists of connected channels placed on the edges of a honeycomb structure. The spreading of particles is superdiffusive due to the existence of ballistic trajectories which we term perfect paths. Simulations give a time exponent of 1.72 for the mean square displacement and a starlike, i.e., a

Kostadin Koroutchev, Elka Korutcheva

This paper investigates the conditions for the formation of local bumps in the activity of binary attractor neural networks with spatially dependent connectivity. We show that these formations are observed when asymmetry between the activity during the retrieval and learning is imposed. Analytical approximation for the order parameters is derived. The corres

S. N. Artemenko, S. V. Remizov

A new non-Fermi-liquid state of quasi-one-dimensional conductors is suggested in which electronic system exists in a form of collection of bounded Luttinger liquids stabilized by impurities. This state is shown to be stable towards interchain electron hopping at low temperatures. Electronic spectrum of the system contains zero modes and collective excitation

D. Beckmann, H. v. Löhneysen

We report on electronic transport properties of mesoscopic superconductor-ferromagnet spin-valve structures. Two ferromagnetic iron leads form planar tunnel contacts to a superconducting aluminum wire, where the distance of the two contacts is of the order of the coherence length of the aluminum. We observe a negative non-local resistance which can be explai

S. N. Artemenko, S. V. Remizov

A narrow energy band of the electronic spectrum in some direction in low-dimensional crystals may lead to a negative differential conductance and N-shaped I-V curve that results in an instability of the uniform stationary state. A well-known stable solution for such a system is a state with electric field domain. We have found a uniform stable solution in th

M. Krawiec, M. Jalochowski, M. Kisiel

The electronic structure of Si(111)-(6x6)Au surface covered with submonolayer amount of Pb is investigated using scanning tunneling spectroscopy. Already in small islands of Pb with thickness of 1 ML Pb$_{(111)}$ and with the diameter of only about 2 nm we detected the quantized electronic state with energy 0.55 eV below the Fermi level. Similarly, the I(V)

Jia Li, Gang Zhou, Haitao Liu, Wenhui Duan

First-principles calculations reveal that the adsorption of representative first-row atoms with different electronegativity, such as lithium (Li), carbon (C) and fluorine (F), on zigzag single-walled boron nitride nanotubes (BNNTs) exhibits surprising selectivity. The adsorption energy and adsorption site are dependent upon the chemical activity of adsorbate

M. V. Entin, L. I. Magarill

The steady current induced by electromagnetic field in a 2D system with asymmetric scatterers is studied. The scatterers are assumed to be oriented cuts with one diffusive and another specular sides. Besides, the existence of isotropic impurity scatterers is assumed. This simple model simulates the lattice of half-disk which have been studied numerically rec

L. Seetha Lakshmi, V. Sridharan, R. Rawat, V. S. Sastry

We discuss the effects of local structure on the electrical transport and magnetic properties of La(0.67)Ca(0.33)Mn(1-x)Ti(x)O(3) system.Based on the intercomparison of the structure, transport and magnetic properties of the Mn site substituted La(0.67)Ca(0.33)MnO(3) with isovalent diamagnetic and paramagnetic ions, we argue that local structural effects hav

R. K. Zheng, Hongwei Gu, Bing Xu, K. K. Fung

Monodispersed magnetite (Fe3O4) nanoparticles were synthesized. Transmission electron microscopy study shows that the nanoparticles are in the shape of Wagner-Seitz crystals. The magnetite nanoparticles self-assemble into body-centered cubic superlattice, in which the nanoparticles have the same crystallographic orientations. Shape plays a very critical role

Gregory P. Bewley, Daniel P. Lathrop, Katepalli R. Sreenivasan

Matter at low temperatures exhibits unusual properties such as superfluidity, superconductivity, Bose-Einstein condensation, and supersolidity. These states display quantum mechanical behaviours at scales much larger than atomic dimensions. As in many phase transitions, defects can occur during the transition to the low temperature state. The study of these

J. Wang, K. S. Chan

We study equilibrium pure spin current through tunnelling junctions at zero bias. The two leads of the junctions connected via a thin insulator barrier, can be either a ferromagnetic metal (FM) or a nonmagnetic high-mobility two-dimensional electron gas (2DEG) with Rashba spin orbital interaction (RSOI) or Dresselhaus spin orbital interaction (DSOI). As a le

M. A. Gallis, J. R. Torczynski, D. J. Rader, M. Tij

The state of a single-species monatomic gas from near-equilibrium to highly nonequilibrium conditions is investigated using analytical and numerical methods. Normal solutions of the Boltzmann equation for Fourier flow (uniform heat flux) and Couette flow (uniform shear stress) are found in terms of the heat-flux and shear-stress Knudsen numbers. Analytical s

J. G. Brankov, Vl. V. Papoyan, V. S. Poghosyan, V. B. Priezzhev

The totally asymmetric simple exclusion process in discrete time is considered on finite rings with fixed number of particles. A translation-invariant version of the backward-ordered sequential update is defined for periodic boundary conditions. We prove that the so defined update leads to a stationary state in which all possible particle configurations have

G. Mazzarella, S. M. Giampaolo, F. Illuminati

For systems of interacting, ultracold spin-zero neutral bosonic atoms, harmonically trapped and subject to an optical lattice potential, we derive an Extended Bose Hubbard (EBH) model by developing a systematic expansion for the Hamiltonian of the system in powers of the lattice parameters and of a scale parameter, the {\it lattice attenuation factor}. We id

T. Dahm, P. J. Hirschfeld, D. J. Scalapino, L. Zhu

A new generation of angular-resolved photoemission spectroscopy (ARPES) measurements on the cuprate superconductors offer the promise of enhanced momentum and energy resolution. In particular, the energy and temperature dependence of the on-shell nodal (k_x=k_y) quasiparticle scattering rate can be studied. In the superconducting state, low temperature trans

M. Lazzeri, S. Piscanec, F. Mauri, A. C. Ferrari

We demonstrate the key role of phonon occupation in limiting the high-field ballistic transport in metallic carbon nanotubes. In particular, we provide a simple analytic formula for the electron transport scattering length, that we validate by accurate first principles calculations on (6,6) and (11,11) nanotubes. The comparison of our results with the scatte

Cigdem Capan, kamran Behnia

In a recent letter, Alexandrov and Zavaritsky propose a model to explain the anomalous Nernst signal observed in the normal state of hole-doped cuprates. The aim of this comment is to recall that one of the main assumptions of the authors regarding the experimental data is false.

Andrew J. Cunningham, Adam Frank, Eric G. Blackman

We present a series of numerical studies of the interaction of colliding radiative, hydrodynamic young stellar outflows. We study the effect of the collision impact parameter on the acceleration of ambient material and the degree to which the flow is isotropized by the collision as a mechanism for driving turbulence in the parent molecular cloud. Our results

Amparo Marco, Ignacio Negueruela, Christian Motch

Combination of high-precision photometry and spectroscopy allows the detailed study of the upper main sequence in open clusters. We are carrying out a comprehensive study of a number of clusters containing Be stars in order to evaluate the likelihood that a significant number of Be stars form through mass exchange in a binary. Our first results show that mos

Yangsen Yao, Q. Daniel Wang

X-ray absorption spectroscopy provides a potentially powerful tool in determining the metal abundances in various phases of the interstellar medium (ISM). We present a case study of the sight line toward 4U 1820-303 (Galactic coordinates l, b=2.79, -7.91 and distance = 7.6 kpc), based on Chandra Grating observations. The detection of OI, OII, OIII, OVII, OVI

Jesper Sommer-Larsen

Extended, soft X-ray emission from the halo of a very large disk galaxy has been detected out to r~20-40 kpc. The luminosity and surface brightness distribution is in very good agreement with predictions by recent, cosmological galaxy formation models. Predictions of Ly-alpha emission, associated with ``cold&#39;&#39; accretion of filamentary gas onto galaxi

Sébastien Peirani, Fabrice Durier, José Antonio De Freitas Pacheco

Cosmological N-body simulations were performed to study the evolution of the phase-space density Q = rho/sigma^3 of dark matter halos. No significant differences in the scale relations Q ~ sigma^(-2.1) or Q ~ M^(-0.82) are seen for &#34;cold&#34; or &#34;warm&#34; dark matter models. The follow up of individual halos from z = 10 up to the present time indica

N. Bartolo, S. Matarrese, A. Riotto

We calculate the full second-order radiation transfer function for Cosmic Microwave Background anisotropies on large angular scales in a flat universe filled with matter and cosmological constant. It includes (i) the second-order generalization of the Sachs-Wolfe effect, and of (ii) both the early and late Integrated Sachs-Wolfe effects, (iii) the contributi

Daniel De Marco, Todor Stanev, F. W. Stecker

We discuss the production of cosmogenic neutrinos on extragalactic infrared photons in a model of its cosmological evolution. The relative importance of these infrared photons as a target for proton interactions is significant, especially in the case of steep injection spectra of the ultrahigh energy cosmic rays. For an E$^{-2.5}$ cosmic ray injection spectr

A. Raman, M. Lisanti, D. J. Wilner, C. Qi

We present Submillimeter Array observations of the Herbig Ae star HD169142 in 1.3 millimeter continuum emission and 12CO J=2-1 line emission at 1.5 arcsecond resolution that reveal a circumstellar disk. The continuum emission is centered on the star position and resolved, and provides a mass estimate of about 0.02 solar masses for the disk. The CO images sho

A. P. Boss

We present a suite of three dimensional radiative gravitational hydrodynamics models suggesting that binary stars may be quite capable of forming planetary systems similar to our own. The new models with binary companions do not employ any explicit artificial viscosity, and also include the third (vertical) dimension in the hydrodynamic calculations, allowin

Adam W. Rengstorf, Robert J. Brunner, Brian C. Wilhite

We present variability and multi-wavelength photometric information for the 933 known quasars in the QUEST Variability Survey. These quasars are grouped into variable and non-variable populations based on measured variability confidence levels. In a time-limited synoptic survey, we detect an anti-correlation between redshift and the likelihood of variability

A. Mercurio, P. Merluzzi, C. P. Haines, A. Gargiulo

We present the Shapley Optical Survey, a photometric study covering a 2 deg^2 region of the Shapley Supercluster core at z ~ 0.05 in two bands (B and R). The galaxy sample is complete to B=22.5 (>M^*+6, N_{gal}=16588), and R=22.0 (>M^*+7, N_{gal}=28008). The galaxy luminosity function cannot be described by a single Schechter function due to dips apparent at

P. Chatterjee, A. R. Choudhuri, K. Petrovay

Following an earlier proposal by Choudhuri (2003) for the origin of twist in the magnetic fields of solar active regions, we model the penetration of a wrapped up background poloidal field into a toroidal magnetic flux tube rising through the solar convective zone. The rise of the straight, cylindrical flux tube is followed by numerically solving the inducti

F. Montagni, A. Maselli, E. Massaro, R. Nesci

We address the topic of the Intra-Night Optical Variability of the BL Lac object S5 0716+714. To this purpose a long term observational campaign was performed, from 1996 to 2003, which allowed the collection of a very large data set, containing 10,675 photometric measurements obtained in 102 nights. The source brightness varied in a range of about 2 mag, alt

S. Viti, J. M. Girart, J. Hatchell

Context. A molecular survey recently performed ahead of HH~2 supports the idea that the observed molecular enhancement is due to UV radiation from the HH object. Aims. The aim of the present work is to determine whether all HH objects with enhanced HCO$^+$ emission ahead of them also exhibit the same enhanced chemistry as HH~2. We thus observed several molec

J. Albert, MAGIC collaboration

Recently, the Galactic Center has been reported to be a source of very high energy (VHE) gamma-rays by the VERITAS, CANGAROO and HESS experiments. The energy spectra as measured by these experiments show substantial differences. In this Letter we present MAGIC observations of the Galactic Center, resulting in the detection of a differential gamma-ray flux co

Kenji Bekki

Recent observational studies have revealed star-to-star abundance inhomogeneity among light elements (e.g., C, N, O, Na, and Al) of stars on the main sequence in the Galactic globular clusters (GCs). One of promising interpretations for this result is that the observed abundance inhomogeneity is due to the second generation of stars formed from ejecta of the

A. Mastichiadis, D. Kazanas

We present the spectral and temporal radiative signatures expected within the &#34;Supercritical Pile&#34; model of Gamma Ray Bursts (GRB). This model is motivated by the need for a process that provides the dissipation necessary in GRB and presents a well defined scheme for converting the energy stored in the relativistic protons of the Relativistic Blast W

Avery Meiksin

The colours of high redshift Type II QSOs are synthesized from observations of moderate redshift systems. It is shown that Type II QSOs are comparable to starbursts in their success at matching the colours of z_850-dropouts and i_775-drops in the Hubble Ultra Deep Field, and more naturally account for the bluest objects detected. Type II QSOs may also accoun

Francesc Ferrer, Tanmay Vachaspati

We show that a tangle of light superconducting strings in the Milky Way could be the source of the observed 511 KeV emission from electron-positron annihilation in the Galactic bulge. The scenario predicts a flux that is in agreement with observations if the strings are at the ~ 1 TeV scale making the particle physics within reach of planned accelerator expe

Felix Stoehr

We use a high-resolution simulation of a galaxy-sized dark matter halo, published simulated data as well as four cluster-sized haloes from Fukushige, Kawai & Makino to study the inner halo structure in a Lambda cold dark matter cosmology. We find that the circular velocity curves are substantially better described by Stoehr et al. (SWTS) profiles than by Nav

Sergey N. Solodukhin

The holographic duality can be extended to include quantum theories with broken coordinate invariance leading to the appearance of the gravitational anomalies. On the gravity side one adds the gravitational Chern-Simons term to the bulk action which gauge invariance is only up to the boundary terms. We analyze in detail how the gravitational anomalies origin

Fariel Shafee

We first review and critically examine some basic concepts and ambiguities related to quantum mechanics and quantum measurement to understand the success and shortcomings of current theories. We also touch on ideas regarding expression of variables within a complex system. Then we discuss a model for quantum measurement proposed by us, in which the quantum s

Ursula Hamenstaedt

Let S be an oriented surface of finite type of genus g with m punctures and where 3g-3+m>1. We show that the mapping class group M(S) of S is quasi-isometrically rigid. We also give a different proof of the following result of Behrstock and Minsky: The homological dimension of the asmyptotic cone of M(S) of S equals 3g-3+m.

Jakub Duda

We find an equivalent condition for a real function $f:[a,b]\to\R$ to be Lebesgue equivalent to an $n$-times differentiable function ($n\geq 2$); a simple solution in the case $n=2$ appeared in an earlier paper. For that purpose, we introduce the notions of $CBVG_{1/n}$ and $SBVG_{1/n}$ functions, which play analogous roles for the $n$-th order differentiabi

M. Hasselfield, Taejin Lee, G. W. Semenoff, P. C. E. Stamp

We revisit the exact solution of the two space-time dimensional quantum field theory of a free massless boson with a periodic boundary interaction and self-dual period. We analyze the model by using a mapping to free fermions with a boundary mass term originally suggested in ref.[22]. We find that the entire SL(2,C) family of boundary states of a single boso

Kevin Bundy, Richard S. Ellis, Christopher J. Conselice, James E. Taylor

We characterize the mass-dependent evolution in a large sample of more than 8,000 galaxies using spectroscopic redshifts drawn from the DEEP2 Galaxy Redshift Survey in the range 0.4 < z < 1.4 and stellar masses calculated from K-band photometry obtained at Palomar Observatory. Using restframe (U-B) color and [OII] equivalent widths, we distinguish star-formi