January 2006 arXiv papers — page 32

Lin-Tian Luh

In the field of radial basis functions mathematicians have been endeavouring to find infinitely differentiable and compactly supported radial functions. This kind of functions is extremely important. One of the reasons is that its error bound will converge very fast. However there is hitherto no such function which can be expressed in a simple form. This is

Lin-Tian Luh

It's well-known that there is a very powerful error bound for Gaussians put forward by Madych and Nelson in 1992. It's of the form$% | f(x)-s(x)| \leq (Cd)^{\frac{c}{d}}\left\Vert f\right\Vert_{h}$ where $C,c$ are constants, $h$ is the Gaussian function, $% s$ is the interpolating function, and d is called fill distance which, roughly speaking, measu

George Kordzakhia, Steven P. Lalley

The Northeast Model is a spin system on the two-dimensional integer lattice that evolves according to the following rule: Whenever a site's southerly and westerly nearest neighbors have spin $1$, it may reset its own spin by tossing a $p$-coin; at all other times, its spin remains frozen. It is proved that the northeast model has a phase transition at $p

Sergey Zlobin

We prove an easy but interesting result about the linear independence of multiple zeta values of different weights.

Federica Galluzzi, Giuseppe Lombardo

In this paper we study the automorphisms group of some $K3$ surfaces which are double covers of the projective plane ramified over a smooth sextic plane curve. More precisely, we study the case of a $K3$ surface of Picard rank two such that there is a rational curve of degree $d$ which is tangent to the sextic in $d$ points.

Claudia Garetto

We introduce different notions of wave front set for the functionals in the dual of the Colombeau algebra $\Gc(\Om)$ providing a way to measure the $\G$ and the $\Ginf$- regularity in $\LL(\Gc(\Om),\wt{\C})$. For the smaller family of functionals having a ``basic structure'' we obtain a Fourier transform-characterization for this type of generalized

Daniel Barlet

The aim of this fisrt part is to introduce, for a rather large class of hypersurface singularities with 1 dimensionnal locus, the analog of the Brieskorn lattice at the origin (the singular point of the singular locus). The main results are the finitness theorem for the corresponding (a,b)-module obtained via Kashiwara's constructibility theorem, and non

Joel Kamnitzer

In an earlier work, we proved that MV polytopes parameterize both Lusztig's canonical basis and the Mirkovic-Vilonen cycles on the Affine Grassmannian. Each of these sets has a crystal structure (due to Kashiwara-Lusztig on the canonical basis side and due to Braverman-Finkelberg-Gaitsgory on the MV cycles side). We show that these two crystal structures

B. Feigin, E. Feigin

In this paper we give two realizations of the restricted Kostka polynomials for $\sl_2$. Firstly we identify the restricted Kostka polynomials with a characters of the zero homology of the current algebra with a coefficients in a certain modules. As a corollary we reobtain the alternating sum formula. Secondly we show that the restricted Kostka polynomials a

Eric M. Rains

We construct a family of BC_n-symmetric biorthogonal abelian functions generalizing Koornwinder's orthogonal polynomials, and prove a number of their properties, most notably analogues of Macdonald's conjectures. The construction is based on a direct construction for a special case generalizing Okounkov's interpolation polynomials. We show that t

A. de la Macorra, U. Filobello, G. German

We study the dynamics of the tachyon field $T$. We derive the mass of the tachyon as the pole of the propagator which does not coincide with the standard mass given in the literature in terms of the second derivative of $V(T)$ or $Log[V(T)]$. We determine the transformation of the tachyon in order to have a canonical scalar field $ϕ$. This transformation red

G. X. Peng

The general relation between the standard expansion coefficients and the beta function for the QCD coupling is exactly derived in a mathematically strict way. It is accordingly found that an infinite number of logarithmic terms are lost in the standard expansion with a finite order, and these lost terms can be given in a closed form. Numerical calculations,

Michael Thies

During the last few years, the phase diagram of the large N Gross-Neveu model in 1+1 dimensions at finite temperature and chemical potential has undergone a major revision. Here we present a streamlined account of this development, collecting the most important results. Quasi-one-dimensional condensed matter systems like conducting polymers provide real phys

Holger B. Nielsen, Masao Ninomiya

If a macroscopic (random) classical system is put into a random state in phase space, it will of course the most likely have an almost maximal entropy according to second law of thermodynamics. We will show, however, the following theorem: If it is enforced to be periodic with a given period $T$ in advance, the distribution of the entropy for the otherwise r

J. D. Vergados

Various issues related to the direct detection of supersymmetric dark matter are reviewed. Such are: 1) Construction of supersymmetric models with a number of parameters, which are constrained from the data at low energies as well as cosmological observations. 2) A model for the nucleon, in particular the dependence on the nucleon cross section on quarks oth

G. Heinrich

A method based on sector decomposition has been developed to calculate the double real radiation part of the process e+e- to 3 jets at next-to-next-to-leading order. It is shown in an example that the numerical cancellation of soft and collinear poles works well. The method is flexible to include an arbitrary measurement function in the final Monte Carlo pro

Jiri Chyla

he excess of data on the total cross section of $\bar{b}b$ production in $γγ$ collisions over QCD predictions, observed by L3, OPAL and DELPHI Collaborations at LEP2, has so far defied explanation. The recent final analysis of L3 data has brought important new information concerning the dependence of the observed excess on the $γγ$ collisions energy $W_{γγ}$

D. K. Choudhury, P. K. Sahariah

Polarised singlet DGLAP equations are solved by applying the method of characteristics. The singlet equations are first transformed into a pair of coupled partial differential equations by a Taylor series expansion valid to be at small x. The equations are then reduced to canonical forms and the resultant equations solved by applying the method of characteri

Chong-Xing Yue, Zheng-Jun Zong, Li-Li Xu, Jian-Xing Chen

In the context of topcolor assisted technicolor(TC2) models, we study the production of the top-pions $π_{t}^{0,\pm}$ with single top quark via the processes $p\bar{p} \to tπ_{t}^{0}+X$ and $p\bar{p} \to tπ_{t}^{\pm}+X$, and discuss the possibility of detecting these new particles at Tevatron and LHC. We find that it is very difficult to observe the signals

Ariel R. Zhitnitsky

We present arguments suggesting that large size overlapping instantons are the driving mechanism of the confinement-deconfinement phase transition at nonzero chemical potential mu. The arguments are based on the picture that instantons at very large chemical potential in the weak coupling regime are localized configurations with finite size ρ\simμ^{-1}. At t

J. D. Vergados

The recent WMAP data have confirmed that exotic dark matter together with the vacuum energy (cosmological constant) dominate in the flat Universe. Thus the direct dark matter detection, consisting of detecting the recoiling nucleus, is central to particle physics and cosmology. Supersymmetry provides a natural dark matter candidate, the lightest supersymmetr

Konosuke Sawa

We investigate the contribution of extra dimensions to the muon anomalous magnetic moment by using an ADD-type 6-dimensional model. This approach analyzes the extent of the influence of classical brane fluctuations on the magnetic moment. When we consider that the brane fluctuations are static in time, they add new potential terms to the Schr{ö}dinger equati

Frithjof Karsch

We review recent progress in studies of bulk thermodynamics of strongly interacting matter, present results on the QCD equation of state and discuss the status of studies of the phase diagram at non-vanishing quark chemical potential.

Fernando Garcia Flores, Denjoe O'Connor, Xavier Martin

The properties of the phi^4 scalar field theory on a fuzzy sphere are studied numerically. The fuzzy sphere is a discretization of the sphere through matrices in which the symmetries of the space are preserved. This model presents three different phases: uniform and disordered phases, as in the usual commutative scalar field theory, and a non-uniform ordered

Ferdinando Gliozzi

The percolating phase of whatever random percolation process resembles the confining vacuum of a gauge theory in most respects, with a string tension having a well-behaved continuum limit, a non trivial glueball spectrum and a deconfinement transition at a well determined temperature T_c. Simple numerical experiments reveal an underlying, strongly fluctuatin

Maria B. Parappilly, Patrick O. Bowman, Urs M. Heller, Derek B Leinweber

We present an unquenched calculation of the quark propagator in Landau gauge with 2+1 flavors of dynamical quarks. We study the scaling behavior of the quark propagator in full QCD on two lattices with different lattice spacings and similar physical volume. We use configurations generated with an improved staggered (``Asqtad'') action by the MILC collaborati

Raimund Ströhmer

We present a preliminary measurement of the inclusive jet cross-sections based on an integrated luminosity of 378 pb^{-1} acquired with the D0 detector between 2002 and 2004 at a center of mass energy of \sqrt{s}=1.96 TeV and a measurement of azimuthal dijet decorrelations based on an integrated luminosity of 150 pb^{-1}. The cross section measurements are b

Raimund Ströhmer

We report on studies of Bose-Einstein correlations and color reconnection in hadronic W pair production at LEP. Bose-Einstein correlations between identical particles from the decay of different W's are studied by comparing the particle correlation in hadronic W pair decays to those in events which are constructed from the combination of the hadronic par

Tomasz Konopka, Fotini Markopoulou

Many theories are formulated as constrained systems. We provide a mechanism that explains the origin of physical states of a constrained system by a process of selection of noiseless subsystems when the system is coupled to an external environment. Effectively, physical states that solve all the constraints are selected by a passive error correction scheme w

A. V. Toporensky, P. V. Tretyakov

We investigate the cosmological dynamics of a brane Universe when quantum corrections from vacuum polarization are taken into account. New vacuum de Sitter points existing on Randall-Sundrum brane are described. We show also that quantum correction can destroy the DGP de Sitter solution on induced gravity brane.

Stefano Foffa, Michele Papucci, Riccardo Sturani

The original computation did not take into account the initial phase shift. A corrected computation, included as section II in the revised version of gr-qc/0407039, still gives a term proportional to the derivative of the signal, qualitatively confirming the original result.

Marc Schoenauer, Pierre Savéant, Vincent Vidal

An original approach, termed Divide-and-Evolve is proposed to hybridize Evolutionary Algorithms (EAs) with Operational Research (OR) methods in the domain of Temporal Planning Problems (TPPs). Whereas standard Memetic Algorithms use local search methods to improve the evolutionary solutions, and thus fail when the local method stops working on the complete p

Johan Bollen, Marko A. Rodriguez, Herbert Van de Sompel

The status of an actor in a social context is commonly defined in terms of two factors: the total number of endorsements the actor receives from other actors and the prestige of the endorsing actors. These two factors indicate the distinction between popularity and expert appreciation of the actor, respectively. We refer to the former as popularity and to th

Florence Levé, Gwénaël Richomme

We characterize all quasiperiodic Sturmian words: a Sturmian word is not quasiperiodic if and only if it is a Lyndon word. Moreover, we study links between Sturmian morphisms and quasiperiodicity.

Nicholas J. A. Harvey

Basic path-matchings, introduced by Cunningham and Geelen (FOCS 1996), are a common generalization of matroid intersection and non-bipartite matching. The main results of this paper are a new algebraic characterization of basic path-matching problems and an algorithm for constructing basic path-matchings in O(n^w) time, where n is the number of vertices and

Michael Ortega, Sabine Coquillart

Most research on 3D user interfaces aims at providing only a single sensory modality. One challenge is to integrate several sensory modalities into a seamless system while preserving each modality's immersion and performance factors. This paper concerns manipulation tasks and proposes a visuo-haptic system integrating immersive visualization, tactile for

Hong Xu, Wen-Feng Qi

Let $\underline{a}$ be an \textit{l}-sequence generated by a feedback-with-carry shift register with connection integer $q=p^{e}$, where $ p$ is an odd prime and $e\geq 1$. Goresky and Klapper conjectured that when $ p^{e}\notin \{5,9,11,13\}$, all decimations of $\underline{a}$ are cyclically distinct. When $e=1$ and $p>13$, they showed that the set of dist

Stefan M. Moser

We derive new upper and lower bounds on the fading number of multiple-input single-output (MISO) fading channels of general (not necessarily Gaussian) regular law with spatial and temporal memory. The fading number is the second term, after the double-logarithmic term, of the high signal-to-noise ratio (SNR) expansion of channel capacity. In case of an isotr

Maarten R. Wegewijs, Katja C. Nowack

It is demonstrated that non-equilibrium vibrational effects are enhanced in molecular devices for which the effective potential for vibrations is sensitive to the charge state of the device. We calculate the electron tunneling current through a molecule accounting for the two simplest qualitative effects of the charging on the nuclear potential for vibration

J. -P. Ismer, I. Eremin, D. K. Morr

We present a study of the dynamical spin susceptibility in the pseudogap region of the high-T$_c$ cuprate superconductors. We analyze and compare the formation of the so-called resonance peak, in three different ordered states: the $d_{x^2-y^2}$-wave superconducting (DSC) phase, the $d$-density wave (DDW) state, and a phase with coexisting DDW and DSC order.

Sergio L. Morelhao

Diffracted X-ray waves in crystals have relative phases regarding the mathematical format used to describe them. A forward propagating wave can be defined with either negative or positive time evolution, i.e. kr - wt or $wt - kr. Physically measurable quantities are invariant with respect to the choice of definition. This fact has not been clearly emphasized

Luis A. Pugnaloni, Marcos G. Valluzzi, Lucas G. Valluzzi

We simulate the tapping of a bed of hard disks in a rectangular box by using a pseudo dynamic algorithm. In these simulations, arches are unambiguously defined and we can analyze their properties as a function of the tapping amplitud. We find that an order--disorder transition occurs within a narrow range of tapping amplitudes as it has been seen by others.

S. Dong, X. Y. Yao, K. F. Wang, J. -M. Liu

The phase equilibrium in manganites under magnetic field is studied using a two orbital model, based on the equivalent chemical potential principle for the competitive phases. We focus on the magnetic field induced melting process of CE phase in half-doped manganites. It is predicted that the homogenous CE phase begins to decompose into coexisting ferromagne

Sam T. Carr, Boris N. Narozhny, Alexander A. Nersesyan

The system of interacting spinless fermions hopping on a two-leg ladder exhibits a series of quantum phase transitions when subjected to an external magnetic field. At half filling, these are either U(1) Gaussian phase transitions between two phases with distinct types of long-range order or Berezinskii-Kosterlitz-Thouless transitions between ordered and gap

Marcelo Martins de Oliveira, Ronald Dickman

We apply the recently devised quasi-stationary simulation method to study the lifetime and order parameter of the contact process in the subcritical phase. This phase is not accessible to other methods because virtually all realizations of the process fall into the absorbing state before the quasi-stationary regime is attained. With relatively modest simulat

Christopher Bauerle, Francois Mallet, Felicien Schopfer, Dominique Mailly

We present measurements of the phase coherence time \tauphi in quasi one-dimensional Au/Fe Kondo wires and compare the temperature dependence of \tauphi with a recent theory of inelastic scattering from magnetic impurities (Phys. Rev. Lett. 93, 107204 (2004)). A very good agreement is obtained for temperatures down to 0.2 $T_K$. Below the Kondo temperature $

Svetla D. Chakarova Kack, Elsebeth Schroder, Bengt I. Lundqvist, David C. Langreth

It is shown that it is now possible to include van der Waals interactions via a nonempirical implementation of density functional theory to describe the correlation energy in electronic structure calculations on infinite systems of no particular symmetry. The vdW-DF functional [Phys. Rev. Lett. 92, 246401 (2004)] is applied to the adsorption of benzene and n

M. G. Vasin, V. I. Lad'yanov

Structural transitions in melts as well as their dynamics are considered. It is supposed that liquid represents the solution of relatively stable solid-like locally favored structures (LFS) in the surrounding of disordered normal-liquid structures. Within the framework of this approach the step changes of liquid Co viscosity are considered as liquid-liquid t

Sumiyoshi Abe, Stefan Thurner

The Erdos-Renyi classical random graph is characterized by a fixed linking probability for all pairs of vertices. Here, this concept is generalized by drawing the linking probability from a certain distribution. Such a procedure is found to lead to a static complex network with an arbitrary connectivity distribution. In particular, a scale-free network with

W. J. M. Naber, T. Fujisawa, H. W. Liu, W. G. van der Wiel

We report on non-adiabatic transport through a double quantum dot under irradiation of surface acoustic waves generated on-chip. At low excitation powers, absorption and emission of single and multiple phonons is observed. At higher power, sequential phonon assisted tunneling processes excite the double dot in a highly non-equilibrium state. The present syst

Y. He, T. S. Nunner, P. J. Hirschfeld, H. -P. Cheng

The cuprate material BSCCO-2212 is believed to be doped by a combination of cation switching and excess oxygen. The interstitial oxygen dopants are of particular interest because scanning tunnelling microscopy (STM) experiments have shown that they are positively correlated with the local value of the superconducting gap, and calculations suggest that the fu

M. Alimohammadi

For reaction-diffusion processes without exclusion, in which the particles can exist in the same site of a one-dimensional lattice, we study all the integrable models which can be obtained by imposing a boundary condition on the master equation of the asymmetric diffusion process. The annihilation process is also added. The Bethe ansatz solution and the exac

Fabio Sattin

The superstatistics approach recently introduced by Beck [C. Beck and E.G.D. Cohen, Physica A 322, 267 (2003)] is a formalism that aims to deal in a unifying way with a large variety of complex nonequilibrium systems, for which spatio-temporal fluctuations of one intensive variable (the "temperature" 1/b) are supposed to exist. The intuitive explanat

Zi-Xiang Hu, You-Quan Li

We investigate the ground state persistent spin current and the pair entanglement in one-dimensional antiferromagnetic anisotropic Heisenberg ring with twisted boundary conditions. Solving Bethe ansatz equations numerically, we calculate the dependence of the ground state energy on the total magnetic flux through the ring, and the resulting persistent curren

James Day, John Beamish

The recent torsional oscillator results of Kim and Chan suggest a supersolid phase transition in solid 4He. We have used a piezoelectrically driven diaphragm to study the flow of solid helium through an array of capillaries. Our measurements showed no indication of low temperature flow, placing stringent restrictions on supersolid flow in response to a press

M. G. Vasin

Possibility of description of the glass transition in terms of critical dynamics considering a hierarchy of the intermodal relaxation time is shown. The generalized Vogel-Fulcher law for the system relaxation time is derived in terms of this approach. It is shown that the system satisfies the fluctuating--dissipative theorem in case of the absence of the int

K. O'Neill, E. Slot, R. E. Thorne, H. S. J. van der Zant

We have fabricated longitudinal nanoconstrictions in the charge-density wave conductor (CDW) NbSe$_{3}$ using a focused ion beam and using a mechanically controlled break-junction technique. Conductance peaks are observed below the T$_{P1}$$=145 $K and T$_{P2}$$=59 $K CDW transitions, which correspond closely with previous values of the full CDW gaps $2Δ_{1}

G. Buscarino, S. Agnello, F. M. Gelardi

We report an experimental study by electron paramagnetic resonance (EPR) of gamma ray irradiation induced point defects in oxygen deficient amorphous SiO2 materials. We have found that three intrinsic (E'gamma, E'delta and triplet) and one extrinsic ([AlO4]0) paramagnetic centers are induced. All the paramagnetic defects but E'gamma center are fo

Daniel J. Cross

The recently proposed Cooperstock-Tieu galaxy model claims to explain the flat rotation curves without dark matter. The purpose of this note is to show that this model is internally inconsistent and thus cannot be considered a valid solution. Moreover, by making the solution consistent the ability to explain the flat rotation curves is lost.

Yuki Kaneko, Robert D. Preece, Michael S. Briggs, William S. Paciesas

We present a systematic spectral analysis of 350 bright GRBs observed with BATSE, with high spectral and temporal resolution. Our sample was selected from the complete set of 2704 BATSE GRBs, and included 17 short GRBs. To obtain well-constrained spectral parameters, four different photon models were fitted and the spectral parameters that best represent eac

G. Beccari, F. R. Ferraro, A. Possenti, E. Valenti

We have used a proper combination of multiband high-resolution {\it HST-WFPC2} and wide-field ground based observations to image the galactic globular cluster NGC 6266 (M62). The extensive photometric data set allows us to determine the center of gravity and to construct the most extended radial profile ever published for this cluster including, for the firs

Gy. M. Szabo, K. Szatmary, Zs. Diveki, A. Simon

We examined which exo-systems contain moons that may be detected in transit. We numerically modeled transit light curves of Earth-like and giant planets that cointain moons with 0.005--0.4 Earth-mass. The orbital parameters were randomly selected, but the entire system fulfilled Hill-stability. We conclude that the timing effect is caused by two scenarios: t

B. Gendre, M. Boer

SWIFT bursts appear to be more distant than previous bursts. We present the Boer & Gendre relation that link redshift and afterglow luminosities. Taking advantage of the XMM-Newton, Chandra and BeppoSAX catalogs, and using this relation, we have investigated the redshift distribution of GRBs. We find that XMM burst sources with unknown redshift appear to be

S. Schanne, J. -L. Atteia, D. Barret, S. Basa

Gamma-ray bursts (GRB), at least those with a duration longer than a few seconds are the most energetic events in the Universe and occur at cosmological distances. The ECLAIRs micro-satellite, to be launched in 2009, will provide multi-wavelength observations of GRB, to study their astrophysics and to use them as cosmological probes. Furthermore in 2009 ECLA

Peter H. Hauschildt, E. Baron

We describe a highly flexible framework to solve 3D radiation transfer problems in scattering dominated environments based on a long characteristics piece-wise parabolic formal solution and an operator splitting method. We find that the linear systems are efficiently solved with iterative solvers such as Gauss-Seidel and Jordan techniques. We use a sphere-in

Graham P. Smith, David J. Sand, Eiichi Egami, Daniel Stern

Gravitational lensing by massive galaxy clusters is a powerful tool for the discovery and study of high redshift galaxies, including those at z>=6 likely responsible for cosmic re-ionization. Pello et al. recently used this technique to discover a candidate gravitationally magnified galaxy at z=10 behind the massive cluster lens Abell 1835 (z=0.25). We prese

O. Gonzalez-Martin, A. C. Fabian, J. S. Sanders

We report the results of a study of X-ray point sources coincident with the High Velocity System (HVS) projected in front of NGC 1275. A very deep X-ray image of the core of the Perseus cluster made with the Chandra Observatory has been used. We find a population of Ultra-Luminous X-ray sources (ULX; 7 sources with LX [0.5-7 keV] > 7x10^39 erg/s). As with th

P. Boumis, S. Akras, E. M. Xilouris, F. Mavromatakis

The presentation of new results from an [O III] 5007 A survey in a search for planetary nebulae (PNe) in the galactic bulge is continued. A total of 60 objects, including 19 new PNe, have been detected in the remaining 34 per cent of the survey area, while 41 objects are already known. Deep Halpha+[N II] CCD images as well as low resolution spectra have been

I. Pillitteri, G. Micela, F. Damiani, S. Sciortino

We report on a deep X-ray survey of the young (~ 140 Myr), rich open cluster NGC 2516 obtained with the EPIC camera on board the XMM-Newton satellite. By combining data from six observations, a high sensitivity, greater than a factor 5 with respect to recent Chandra observations, has been achieved. We detected 431 X-ray sources and 234 of them have as optica

N. F. Martin, M. J. Irwin, R. A. Ibata, B. C. Conn

As part of our radial velocity survey of low Galactic latitude structures that surround the Galactic disc, we report the detection of the so called Monoceros Ring in the foreground of the Carina dwarf galaxy at Galactic coordinates (l,b)=(260,-22) based on VLT/FLAMES observations of the dwarf galaxy. At this location, 20 degrees in longitude greater than pre

B. Balmaverde, A. Capetti, P. Grandi

We present results from Chandra observations of the 3C/FRI sample of low luminosity radio-galaxies. We detected a power-law nuclear component in 12 objects out of the 18 with available data. In 4 galaxies we detected nuclear X-ray absorption at a level of about N_H= (0.2-6)e22 cm-2. X-ray absorbed sources are associated with the presence of highly inclined d

Shogo Nishiyama, Tetsuya Nagata, Nobuhiko Kusakabe, Noriyuki Matsunaga

We have determined the ratios of total to selective extinction in the near-infrared bands (J, H, Ks) toward the Galactic center from the observations of the region |l| < 2.0deg and 0.5deg < |b| < 1.0deg with the IRSF telescope and the SIRIUS camera. Using the positions of red clump stars in color-magnitude diagrams as a tracer of the extinction and reddening

N. Lodieu, J. Bouvier, D. J. James, W. -J. de Wit

We present the first deep, optical, wide-field imaging survey of the young open cluster Collinder 359, complemented by near-infrared follow-up observations. This study is part of a large programme aimed at examining the dependence of the mass function on environment and time. We have surveyed 1.6 square degrees in the cluster, in the I and z filters, with th

P. Deroo, H. Van Winckel, M. Min, L. B. F. M. Waters

We present the first mid-IR long baseline interferometric observations of the circumstellar matter around binary post-AGB stars. Two objects, SX Cen and HD 52961, were observed using the VLTI/MIDI instrument during Science Demonstration Time. Both objects are known binaries for which a stable circumbinary disc is proposed to explain the SED characteristics.

S. Andreon, H. Quintana, M. Tajer, G. Galaz

The present paper focuses on the much debated Butcher-Oemler effect: the increase with redshift of the fraction of blue galaxies in clusters. Considering a representative cluster sample made of seven group/clusters at z~0.35, we have measured the blue fraction from the cluster core to the cluster outskirts and the field mainly using wide field CTIO images. T

C. Olczak, S. Pfalzner, R. Spurzem

The relevance of encounters on the destruction of protoplanetary discs in the Orion Nebula Cluster (ONC) is investigated by combining two different types of numerical simulation. First, star-cluster simulations are performed to model the stellar dynamics of the ONC, the results of which are used to investigate the frequency of encounters, the mass ratio and

V. Strazzullo, P. Rosati, S. A. Stanford, C. Lidman

We determined the K band luminosity function (LF) of cluster galaxies at redshift z~1.2, using near-infrared images of three X-ray luminous clusters at z=1.11,1.24,1.27. The composite LF was derived down to M*+4, by means of statistical background subtraction, and is well described by a Schechter function with K*=20.5 AB mag and alpha=-1. From the K band com

Falk Herwig, Bernd Freytag, Robert M. Hueckstaedt, Francis X. Timmes

We present the first hydrodynamic, multi-dimensional simulations of He-shell flash convection. Specifically, we investigate the properties of shell convection at a time immediately before the He- luminosity peak during the 15th thermal pulse of a stellar evolution track with initially two solar masses and metallicity Z=0.01. This choice is a representative e

Z. Uhm, A. M. Beloborodov

We propose a simple mechanical model for relativistic explosions with both forward and reverse shocks, which allows one to do fast calculations of GRB afterglow. The blast wave in the model is governed by pressures P_F and P_R at the forward and reverse shocks. We show that the simplest assumption P_F=P_R is in general inconsistent with energy conservation l

Hy Trac, Ue-Li Pen

We present an out-of-core hydrodynamic code for high resolution cosmological simulations that require terabytes of memory. Out-of-core computation refers to the technique of using disk space as virtual memory and transferring data in and out of main memory at high I/O bandwidth. The code is based on a two-level mesh scheme where short-range physics is solved

Yun Wang

Baryon acoustic oscillations (BAO) in the galaxy power spectrum allows us to extract the scale of the comoving sound horizon at recombination, a cosmological standard ruler accurately determined by the cosmic microwave background anisotropy data. We examine various issues important in the use of BAO to probe dark energy. We find that assuming a flat universe

Emilio Elizalde, Rui Neves

We analyze the dynamics of an AdS5 braneworld with matter fields when gravity is allowed to deviate from the Einstein form on the brane. We consider exact 5-dimensional warped solutions which are associated with conformal bulk fields of weight -4 and describe on the brane the following three dynamics: those of inhomogeneous dust, of generalized dark radiatio

Syu Kato

Let G be a complex symplectic group. We introduce a G x (C ^x) ^{l + 1}-variety N_{l}, which we call the l-exotic nilpotent cone. Then, we realize the Hecke algebra H of type C_n ^(1) with three parameters via equivariant algebraic K-theory in terms of the geometry of N_2. This enables us to establish a Deligne-Langlands type classification of "non-critical"

Alexei Krouglov

Author presents mathematical model for acting-on-a-distance attractive and repulsive forces based on propagation of energy waves that produces Newton expression for gravitational and Coulomb expression for electrostatic forces. Model uses mathematical observation that difference between two inverse exponential functions of the distance asymptotically converg

Cecilia Lunardini

I derive an upper bound on the electron neutrino component of the diffuse supernova neutrino flux from the constraint on the antineutrino component at SuperKamiokande. The connection between antineutrino and neutrino channels is due to the similarity of the muon and tau neutrino and antineutrino fluxes produced in a supernova, and to the conversion of these

F. R. Ferraro, E. Valenti, O. Straniero, L. Origlia

We present an empirical calibration of the Mixing-Length free parameter $α$ based on a homogeneous Infrared database of 28 Galactic globular clusters spanning a wide metallicity range (-2.15$<$[Fe/H]$<$-0.2). Empirical estimates of the red giant effective temperatures have been obtained from infrared colors. Suitable relations linking these temperatures to t

Heron Caldas

We derive the energy of the surface between the normal and superfluid components of a mixed phase of a system composed of two particle species with different densities. The surface energy is obtained by the integration of the free energy density in the interface between the two phases. We show that the mixed phase remains as the favored ground state over the

Lianyi He, Meng Jin, Pengfei Zhuang

A general analysis for the competition between breached pairing (BP) and LOFF pairing mechanisms in asymmetric fermion superfluids is presented in the frame of a four fermion interaction model. Two physical conditions which can induce mismatched Fermi surfaces are considered: (1) fixed chemical potential asymmetry $δμ$ and (2) fixed fermion number asymmetry

Boaz Tsaban

In a previous work with Mildenberger and Shelah, we showed that the combinatorics of the selection hypotheses involving tau-covers is sensitive to the selection operator used. We introduce a natural generalization of Scheepers&#39; selection operators, and show that: (1) A slight change in the selection operator, which in classical cases makes no difference,

Y. Niimi, T. Matsui, H. Kambara, K. Tagami

We measured the electronic local density of states (LDOS) of graphite surfaces near monoatomic step edges, which consist of either the zigzag or armchair edge, with the scanning tunneling microscopy (STM) and spectroscopy (STS) techniques. The STM data reveal that the $(\sqrt{3} \times \sqrt{3}) R 30^{\circ}$ and honeycomb superstructures coexist over a leng

Guoqiang Cui, J. M. Hannigan, R. Loeckenhoff, F. M. Matinaga

We report a novel hemispherical micro-cavity that is comprised of a planar integrated semiconductor distributed Bragg reflector (DBR) mirror, and an external, concave micro-mirror having a radius of curvature $50\mathrm{μm}$. The integrated DBR mirror containing quantum dots (QD), is designed to locate the QDs at an antinode of the field in order to maximize

Kentaro Nagamine, Arthur M. Wolfe, Lars Hernquist

We discuss the detectability of high-redshift galaxies via [CII] 158 micron line emission by coupling an analytic model with cosmological Smoothed Particle Hydrodynamics (SPH) simulations that are based on the concordance Lambda cold dark matter (CDM) model. Our analytic model describes a multiphase interstellar medium irradiated by the far ultra-violet radi

O. D. Azorkina, A. T. Banin, I. L. Buchbinder, N. G. Pletnev

We obtain the one-loop quantum corrections to the Kählerian and superpotentials in the generic chiral superfield model on the nonanticommutative superspace. Unlike all previous works, we use a method which does not require to rewrite a star-product of superfields in terms of ordinary products. In the Kählerian potential sector the one-loop contributions are

Rong-Gen Cai, Nobuyoshi Ohta

Recently,in a paper hep-th/0511197, it was found that non-commutative super Yang-Mills (NCSYM) theory with space-dependent noncommutativity can be formulated as a decoupling limit of open strings ending on D3-branes wrapping a Melvin universe supported by a flux of the NSNS B-field. Under S-duality, we show that this theory turns into a noncommutative open s

R H D Townsend, J MacDonald

We examine the stability of l=1 and l=2 g modes in a pair of nitrogen-rich Wolf-Rayet stellar models characterized by differing hydrogen abundances. We find that modes with intermediate radial orders are destabilized by a kappa mechanism operating on an opacity bump at an envelope temperature log T ~ 6.25. This `deep opacity bump&#39; is due primarily to L-s

Emmanuel Tannenbaum

This paper develops a highly simplified model with which to analyze the phenomenon of sleep. Motivated by Crick&#39;s suggestion that sleep is the brain&#39;s way of ``taking out the trash,&#39;&#39; a suggestion that is supported by emerging evidence, we consider the problem of the filling and emptying of a tank. At any given time, the tank may take in exte

P. R. Levashov, V. S. Filinov, M. Bonitz, V. E. Fortov

In this work we calculate the thermodynamic properties of hydrogen-helium plasmas with different mass fractions of helium by the direct path integral Monte Carlo method. To avoid unphysical approximations we use the path integral representation of the density matrix. We pay special attention to the region of weak coupling and degeneracy and compare the resul

Sanshui Xiao, Liu Liu, Min Qiu

Channel drop filters in a plasmon-polaritons metal are studied. It shows that light can be efficiently dropped. Results obtained by the FDTD method are consistent with those from coupled mode theory. It also shows, without considering the loss of the metal, that the quality factor for the channel drop system reaches 4000. The quality factor decreases signifi

G. E. Hahne

Frank Wilczek&#39;s essay &#34;Total Relativity: Mach 2004&#34; (PHYSICS TODAY April, 2004, p. 10) cogently updates the status of the intuitively compelling, but partly unrealized, theory of Mach&#39;s Principle. I think, however, that an important consequence of the Principle has been skipped: that is, the possibility of linear deformations of the internal

Ilona Bednarek, Ryszard Manka

The complete form of the equation of state of strangeness rich proto-neutron and neutron star matter has been obtained. The currently obtained lower value of the Lambda Lambda potential at the level of 5 MeV permits the existence of additional parameter set which reproduces the weaker Lambda Lambda interaction. The effects of the strength of hyperon-hyperon