January 2004 arXiv papers — page 3

A. Dainese

The ALICE experiment is devoted to the study of heavy-ion collisions at the CERN LHC collider. We present the results of a feasibility study for the detection of D^0 \to K^-π^+ decays in Pb-Pb collisions with ALICE.

Ricardo Lopez-Ruiz, Daniele Fournier-Prunaret

A symmetrical cubic discrete coupled logistic equation is proposed to model the symbiotic interaction of two isolated species. The coupling depends on the population size of both species and on a positive constant $λ$, named the mutual benefit. Different dynamical regimes are obtained when the mutual benefit is modified. For small $λ$, the species become ext

A. Bershadskii, J. J. Niemela, A. Praskovsky, K. R. Sreenivasan

Temperature time traces are obtained in turbulent thermal convection at high Rayleigh numbers. Measurements are made in the midplane of the apparatus, near the sidewall but outside the boundary layer. A telegraph approximation for temperature traces is generated by setting the fluctuation amplitude to 1 or 0 depending on whether or not it exceeds the mean va

C. Klein, D. Korotkin, V. Shramchenko

We present a unified approach to theta-functional solutions of the stationary axisymmetric Einstein equations in vacuum. Using Fay's trisecant identity and variational formulas on hyperelliptic Riemann surfaces, we establish formulas for the metric functions, the Ernst potential and their derivatives.

Arturo Ramos

Borisov, Mamaev and Kilin have recently found certain Poisson structures with respect to which the reduced and rescaled systems of certain non-holonomic problems, involving rolling bodies without slipping, become Hamiltonian, the Hamiltonian function being the reduced energy. We study further the algebraic origin of these Poisson structures, showing that the

Yuly Billig

In this paper we study equations of magnetic hydrodynamics with a stress tensor. We interpret this system as the generalized Euler equation associated with an abelian extension of the Lie algebra of vector fields with a non-trivial 2-cocycle. We use the Lie algebra approach to prove the energy conservation law and the conservation of cross-helicity.

M. Lorente

Some particular examples of classical and quantum systems on the lattice are solved with the help of orthogonal polynomials and its connection to continuous models are explored.

M. Jimbo, T. Miwa, Y. Takeyama

We revisit the issue of counting all local fields of the restricted sine-Gordon model, in the case corresponding to a perturbation of minimal unitary conformal field theory. The problem amounts to the study of a quotient of certain space of polynomials which enter the integral representation for form factors. This space may be viewed as a $q$-analog of the s

A. Kokotov, D. Korotkin

In this paper we introduce a new class of integrable systems, naturally associated to Hurwitz spaces (spaces of meromorphic functions over Riemann surfaces). The critical values of the meromorphic functions play the role of "times". Our systems give a natural generalization of the Ernst equation; in genus zero they realize the scheme of deformation o

Arturo Magidin

A group is called capable if it is a central factor group. We consider the capability of finite groups of class two and exponent $p$, $p$ an odd prime. We restate the problem of capability as a problem about linear transformations, which may be checked explicitly for any specific instance of the problem. We use this restatement to derive some known results,

D. A. Dawson, L. G. Gorostiza, A. Wakolbinger

The notion of degree and related notions concerning recurrence and transience for a class of L'evy processes on metric Abelian groups are studied. The case of random walks on a hierarchical group is examined with emphasis on the role of the ultrametric structure of the group and on analogies and differences with Euclidean random walks. Applications to se

David Futer

Let K be a knot that has an unknotting tunnel tau. We prove that K admits a strong involution that fixes tau pointwise if and only if K is a two-bridge knot and tau its upper or lower tunnel.

Naichung Conan Leung, Xiaowei Wang

We study the problem of counting instantons with coassociative boundary condition in (almost) G_(2)-manifolds. This is analog to the open Gromov-Witten theory for counting holomorphic curves with Lagrangian boundary condition in Calabi-Yau manifolds. We explain its relationship with the Seiberg-Witten invariants for coassociative submanifolds.

Yuan Xu

Generalized translation operators for orthogonal expansions with respect to families of weight functions on the unit ball and on the standard simplex are studied. They are used to define convolution structures and modulus of smoothness for these regions, which are in turn used to characterize the best approximation by polynomials in the weighted $L^p$ spaces

Yuan Xu

A polynomial of the form $x^α- p(x)$, where the degree of $p$ is less than the total degree of $x^α$, is said to be least deviation from zero if it has the smallest uniform norm among all such polynomials. We study polynomials of least deviation from zero over the unit ball, the unit sphere and the standard simplex. For $d=3$, extremal polynomial for $(x_1x_

P. Vertesi, Yuan Xu

For a family of weight functions that include the general Jacobi weight functions as special cases, exact condition for the convergence of the Fourier orthogonal series in the weighted $L^p$ space is given. The result is then used to establish a Marcinkiewicz-Zygmund type inequality and to study weighted mean convergence of various interpolating polynomials

Francis Clarke, Martin Crossley, Sarah Whitehouse

We describe explicitly the algebras of degree zero operations in connective and periodic p-local complex K-theory. Operations are written uniquely in terms of certain infinite linear combinations of Adams operations, and we give formulas for the product and coproduct structure maps. It is shown that these rings of operations are not Noetherian. Versions of t

Keizo Hasegawa

We classify four-dimensional compact solvmanifolds up to diffeomorphism, while determining which of them have complex analytic structures. In particular, we shall see that a four-dimensional compact solvmanifold S can be written, up to double covering, as G/L where G is a simply connected solvable Lie group and L is a lattice of G, and every complex structur

Iskander A. Taimanov

We show that any equation from the Davey--Stewartson hierarchy induces an infinite family of geometrically different deformations of tori in $\R^4$ preserving the Willmore functional. We expose a derivation of the Weierstrass representation for surfaces in the four-space which is not unique in difference from the case of surfaces in the three-space. This non

Kari Astala, Matti Lassas, Lassi Paivarinta

We study inverse conductivity problem for an anisotropic conductivity in $L^\infty$ in bounded and unbounded domains. Also, we give applications of the results in the case when Dirichlet-to-Neumann and Neumann-to-Dirichlet maps are given only on a part of the boundary.

Pavle Pandžić

We review the Beilinson-Ginzburg construction of equivariant derived categories of Harish-Chandra modules, and introduce analogues of Zuckerman functors in this setting. They are given by an explicit formula, which works equally well in the case of modules with a given infinitesimal character, which is important if one wants to apply Beilinson-Bernstein loca

Pavle Pandžić

We give an easy proof of the Bernstein-Lunts equivalence of ordinary and equivariant derived categories of Harish-Chandra modules. This proof requires no boundedness assumptions. In the appendix we collect some needed, but not completely standard facts from homological algebra.

A. Beilinson, R. Bezrukavnikov, I. Mirkovic

This is an application of the theory of tilting objects to the geometric setting of perverse sheaves. We show that this theory is a natural framework for Beilinson's gluing of perverse sheaves construction. In the special case of Schubert stratification of a flag variety we get a short proof of Soergel's "Struktursatz", and describe (followin

Vladlen Timorin

Consider a smooth map from a neighborhood of the origin in a real vector space to a neighborhood of the origin in a Euclidean space. Suppose that this map takes all germs of lines passing through the origin to germs of Euclidean circles, or lines, or a point. We prove that under some simple additional assumptions this map takes all lines passing though the o

Johannes Huebschmann

Each of the four critical Severi varieties arises from a minimal holomorphic nilpotent orbit in a simple regular rank 3 hermitian Lie algebra and each such variety lies as singular locus in a cubic--the chordal variety--in the corresponding complex projective space; the cubic and projective space are identified in terms of holomorphic nilpotent orbits. The p

Winfried Bruns, Aldo Conca

Let $X$ be an $n\times m$ matrix of indeterminates over a field $K$ (of sufficiently large characteristic) and $M_t$ the set of $m$-minors of $X$. We consider two objects: (1) the Ress algebra of the polynomial ring $K[X]$ with respect to the ideal $I_t$ generated by $M_t$, and (2) the $A_t$ subalgebra of $K[X]$ generated by $M_t$. Note that $A_t$ is tHE coo

J. X. Lu, Shibaji Roy

This talk reviews our recent work on the construction of SL(2,Z) multiplets of type IIB superfivebranes. We here pay particular attention to the methods employed and some salient features of the solutions.

Marco A. C. Kneipp

We review some recent developments on BPS string solutions and monopole confinement in the Higgs or (color) superconducting phase of deformed N=2 and N=4 super Yang-Mills theories. In particular, the monopole magnetic fluxes are shown to be always integer linear combinations of string fluxes. Moreover, a bound for the threshold length of the string breaking

Albion Lawrence, John McGreevy

We review recent work identifying soft SUSY-breaking terms in local type II string models with branes and magnetic fluxes. We then make a new observation about the configuration space of D-branes in Calabi-Yau backgrounds, and identify vevs for nonperturbative charged hypermultiplets in Calabi-Yau backgrounds with N=2 Fayet-Iliopoulos terms.

G. Grensing, M. Nitschmann

Berezin integration over fermionic degrees of freedom as a standard tool of quantum field theory is analysed from the viewpoint of noncommutative geometry. It is shown that among the variety of contradictory integration prescriptions existing in the current literature, there is only one unique minimal set of consistent rules, which is compatible with Connes&

M. M. Akbar

The thermodynamics of Schwarzschild black holes within an isothermal cavity and the associated Euclidean Dirichlet boundary-value problem are studied for four and higher dimensions in anti-de Sitter (AdS) space. For such boundary conditions classically there always exists a unique hot AdS solution and two or no Schwarzschild-AdS black-hole solutions dependin

M. G. Ivanov

String (membrane) theory could be considered as degenerate case of relativistic continuous media theory. The paper presents models of media, which are continuous distributions of interacting membranes, strings or particles.

H. T. Ozer

Hopf structure of the prototype realizations of the W(2)-algebra and also N=1 superconformal algebra are obtained using the bosonic and also fermionic Feigin-Fuchs type of free massless scalar fields in the operator product expansion (OPE) language.

Elvira Gamiz

In this Ph.D. Thesis we analyze some CP-violating observables in Kaon decays. In Chapters 1-3 we describe the framework in which this Thesis has been developed and establish the definitions and notation. In Chapter 4 we study CP-violating asymmetries in the decays of charged Kaons K\to 3π. The calculation of the ΔI=3/2 contribution to $ε_K'$ in the chira

Bohdan Grzadkowski, Jose Wudka

It has been shown that QED in (1+4)-dimensional space-time, with the fifth dimension compactified on a circle, leads to CP violation (CPV). Depending on fermionic boundary conditions, CPV may be either explicit (through the Scherk--Schwarz mechanism), or spontaneous (via the Hosotani mechanism). The fifth component of the gauge field acquires (at the one-loo

Ralf Hofmann

We show that the form factor of an electron or a muon is unity for the modulus of the momentum transfer away from the Hagedorn temperatures $T^{e}_0\sim m_e$ and $T^μ_0\sim m_μ$ and lower than the hadronic Hagedorn temperature $T^{\tiny{QCD}}_0\sim m_π$. The structure of the electron or the muon is resolved for momemtum transfers comparable to $T^{e,μ}_0$. T

Ralf Hofmann

We propose that charged leptons are the `baryons' of the gauge dynamics subject to a SU(2)$_{e}$$\timesSU(2)_μ\timesSU(2)_τ$ symmetry. The `mesons' of this theory are neutral and thus candidates for dark matter. There is, in addition, a gauge group SU(2)$_{\tiny{CMB}}$ generating the CMB photon. We {\sl compute} the value of $α_{\tiny{em}}$ and the c

M. C. Fujiwara, M. Amoretti, C. Amsler, G. Bonomi

Antihydrogen, the atomic bound state of an antiproton and a positron, was produced at low energy for the first time by the ATHENA experiment, marking an important first step for precision studies of atomic antimatter. This paper describes the first production and some subsequent developments.

T. Uglov

We report first measurements of e+e- -> D(*)+D(*)- processes far above threshold. The cross-sections for e+e- -> DT*+DL*- and e+e- -> D+D*T- at sqrt{s}=10.58 GeV/c2 are measured to be 0.55 +- 0.03 +- 0.05 pb and 0.62 +- 0.03 +- 0.06 pb, respectively. We set upper limits on the cross-sections for e+e- -> DT*+DT*-, e+e- -> DL*+DL*-, e+e- -> D+D*L- and e+e- ->

John Swain

Recent attempts to resolve the ambiguity in the loop quantum gravity description of the quantization of area has led to the idea that $j=1$ edges of spin-networks dominate in their contribution to black hole areas as opposed to $j=1/2$ which would naively be expected. This suggests that the true gauge group involved might be SO(3) rather than SU(2) with atte

Mihalis Dafermos

Two aspects of the widely accepted heuristic picture of the final state of gravitational collapse are the so-called Price law tails, describing the asymptotics of the exterior region of the black hole that forms, and Israel-Poisson's mass inflation scenario, describing the internal structure of the black hole. (The latter scenario, if valid, would indica

V. V. Kassandrov, V. N. Trishin

A special subclass of shear-free null congruences (SFC) is studied, with tangent vector field being a repeated principal null direction of the Weyl tensor. We demonstrate that this field is parallel with respect to an effective affine connection which contains the Weyl nonmetricity and the skew symmetric torsion. On the other hand, a Maxwell-like field can b

R. Schnabel, J. Harms, K. A. Strain, K. Danzmann

The quantum noise of the light field is a fundamental noise source in interferometric gravitational wave detectors. Injected squeezed light is capable of reducing the quantum noise contribution to the detector noise floor to values that surpass the so-called Standard-Quantum-Limit (SQL). In particular, squeezed light is useful for the detection of gravitatio

E. Ferapontov, D. Korotkin, V. Shramchenko

We reduce Boyer-Finley equation to a family of compatible systems of hydrodynamic type, with characteristic speeds expressed in terms of spaces of rational functions. The systems of hydrodynamic type are then solved by the generalized hodograph method, providing solutions of the Boyer-Finley equation including functional parameters.

J. W. Moffat

We use the idea of the symmetry between the spacetime coordinates x^μand the energy-momentum p^μin quantum theory to construct a momentum space quantum gravity geometry with a metric s_{μν} and a curvature P^λ_{μνρ}. For a closed maximally symmetric momentum space with a constant 3-curvature, the volume of the p-space admits a cutoff with an invariant maximu

Vladimir Anashin

The paper study counter-dependent pseudorandom generators; the latter are generators such that their state transition function (and output function) is being modified dynamically while working: For such a generator the recurrence sequence of states satisfies a congruence $x_{i+1}\equiv f_i(x_i)\pmod{2^n}$, while its output sequence is of the form $z_{i}=F_i(

C. Sen, G. Alvarez, E. Dagotto

The physics of manganites appears to be dominated by phase competition among ferromagnetic metallic and charge-ordered antiferromagnetic insulating states. Previous investigations (Burgy {\it et al.}, Phys. Rev. Lett. {\bf 87}, 277202 (2001)) have shown that quenched disorder is important to smear the first-order transition between those competing states, an

Yohai Roichman, Nir Tessler

We present a unified calculation method for variable range hopping transport with a varying charge concentration and a varying applied electrical field. We demonstrate that the major differences between the transport properties measured at high concentration and low concentration can be explained within this framework. In particular the difference between th

Robert M. Konik

We consider the physics of transport through quantum dots in the presence of two tunneling paths. The first path sees electrons hopping on and off the dot while the second path is modeled through a potential scattering-like term. To study the effects of potential scattering, we employ a modified version of the Anderson model. Such a model can be exactly solv

G. Chaboussant, S. T. Ochsenbein, A. Sieber, H. -U. Guedel

We report an inelastic neutron scattering (INS) study under a magnetic field on the frustrated molecular spin cluster $V_{15}$. Several field-dependent transitions are observed and provide a comprehensive understanding of the low-energy quantum spin states. The energy gap $2 Δ_{0}\approx 27(3)μ$eV between the two lowest $S=1/2$ Kramers doublets is unambiguou

Asya Shpiro

Transport properties of magnetic multilayers in current perpendicular to the plane of the layers geometry are defined by diffusive scattering in the bulk of the layers, and diffusive and ballistic scattering across the interfaces. Due to the short screening length in metals, layer by layer treatment of the multilayers is possible, when the macroscopic transp

Afranio Rodrigues Pereira

We investigate classical Heisenberg spins on a conical surface. The energy and configuration of non-trivial spin distributions are obtained using a non-conventional method based on Einstein theory of gravity in lower dimensions.

J. I. Oh, M. J. Naughton

Cantilever magnetometry has been used to measure the upper critical magnetic field $H_{c2}$ of the quasi-one dimensional molecular organic superconductor (TMTSF)$_2$ClO$_4$. From simultaneous resistivity and torque magnetization experiments conducted under precise field alignment, $H_{c2}$ at low temperature is shown to reach 5T, nearly twice the Pauli param

R. J. Gooding, F. Marsiglio, S. Verga, K. S. D. Beach

We outline a partial-fractions decomposition method for determining the one-particle spectral function and single-particle density of states of a correlated electronic system on a finite lattice in the non self-consistent T-matrix approximation to arbitrary numerical accuracy, and demonstrate the application of these ideas to the attractive Hubbard model. We

V. L. Golo, Vl. N. Salnikov, K. V. Shaitan

We study the dynamics of an ensemble of non-interacting harmonic oscillators in a nonlinear dissipative environment described by the Nosé - Hoover model. Using numerical simulation we find the histogram for total energy, which agrees with the analysis of the Nosé - Hoover equations effected with the method of averaging. The histogram does not correspond to G

G. Srinivasan

The synthesis of layered ferrite-lead titanate zirconate (PZT) and lanthanum nanganite-PZT and the observation of giant magneto-electric interactions are discussed. The ferrites used in our studies included pure and Zn substituted cobalt-, nickel- and lithium ferrites. Ferromagnetic manganites used included both calcium and strontium substituted systems. The

T. Nachtrab, D. Koelle, R. Kleiner, C. Bernhard

We have measured interlayer current transport in small sized RuSr2GdCu2O8 single crystals. We find a clear intrinsic Josephson effect showing that the material acts as a natural superconductor-insulator-ferromagnet-insulator-superconductor superlattice. So far, we detected no unconventional behavior due to the magnetism of the RuO2 layers.

Gengchiau Liang, Avik Ghosh, Magnus Paulsson, Supriyo Datta

The electrostatic potential across a short ballistic molecular conductor depends sensitively on the geometry of its environment, and can affect its conduction significantly by influencing its energy levels and wave functions. We illustrate some of the issues involved by evaluating the potential profiles for a conducting gold wire and an aromatic phenyl dithi

I. V. Tokatly

Using the functional integral formulation of a nonequilibrium quantum many-body theory we develop a regular description of a Fermi system with a strong attractive interaction in the presence of an external time-dependent potential. In the strong coupling limit this fermionic system is equivalent to a noequilibrium dilute Bose gas of diatomic molecules. We al

M. Nicodemi, A. Coniglio, A. de Candia, A. Fierro

In the framework of schematic hard spheres lattice models we discuss Edwards' Statistical Mechanics approach to granular media. As this approach appears to hold here to a very good approximation, by analytical calculations of Edwards' partition function at a mean field level we derive the system phase diagram and show that ``jamming'' corresp

A. Sekiyama, H. Fujiwara, A. Higashiya, S. Imada

Unusual temperature and doping dependence of the Mn 3d spectral functions of manganese perovskites Nd1-xSrxMnO3 has been revealed by the high-resolution Mn 2p-3d resonance photoemission. The temperature-dependent spectra cannot be explained by any theoretical model currently under debate, while showing evidence for a microscopic and dynamic phase segregation

Jean Schmittbuhl, Alex Hansen, G. George Batrouni

This is the reply to a Comment by Alava and Zapperi (cond-mat/0401568) on Schmittbuhl, Hansen and Batrouni, PRL, 90, 045505 (2003).

Kausik Sengupta, S. Rayaprol, E. V. Sampathkumaran, Th. Doert

The results of dc magnetization, heat capacity, electrical resistivity (rho) and magnetoresistance measurements are reported in detail for the compounds, RCuAs2 for R= Pr, Nd, Sm, Gd, Tb, Dy, Ho, and Er, crystallizing in HfCuSi2-type tetragonal structure, with the aim of bringing out anomalies among 'normal' (that is, other than Ce and Yb) rare-earth

Takashi Hotta, Elbio Dagotto

Ground-state properties of layered nickelates are investigated based on the orbital-degenerate Hubbard model coupled with lattice distortions, by using umerical techniques. The Néel state composed of spin S=1 ions is confirmed in the undoped limit x=0. At x=1/2, novel antiferromagnetic states, called CE- and E-type phases, are found by increasing the Hund&#3

Chandan Dasgupta, Oriol T. Valls

We study the melting transition of the low-temperature vortex solid in strongly anisotropic layered superconductors with a concentration of random columnar pinning centers small enough so that the areal density of the pins is much less than that of the vortex lines. Both the external magnetic field and the columnar pins are assumed to be oriented perpendicul

N. Barberan

We compare the exact diagonalization ground wave function (calculated wothout any restriction) of a two dimensional droplet submitted to a perpendicular magnetic field with the Laughlin ansatz as the number of electrons increases. The fully polarized case for filling factor 1/3 without lateral confining potential or Zeeman effect is considered. We observe th

J. Martinek, M. Sindel, L. Borda, J. Barnaś

The Kondo effect in quantum dots (QDs) - artificial magnetic impurities - attached to ferromagnetic leads is studied with the numerical renormalization group (NRG) method. It is shown that the QD level is spin-split due to presence of ferromagnetic electrodes, leading to a suppression of the Kondo effect. We find that the Kondo effect can be restored by comp

J. Martinek, Y. Utsumi, H. Imamura, J. Barnas

We study the Kondo effect in a quantum dot which is coupled to ferromagnetic leads and analyse its properties as a function of the spin polarization of the leads. Based on a scaling approach we predict that for parallel alignment of the magnetizations in the leads the strong-coupling limit of the Kondo effect is reached at a finite value of the magnetic fiel

P. Jakobsson, J. Hjorth, E. Ramirez-Ruiz, C. Kouveliotou

We report the discovery of the afterglow of the X-ray rich, long-duration gamma-ray burst GRB 011211 and present evidence for oscillatory behaviour in its early optical light curve. The time-scale of the fluctuations, ~1 hour, is much smaller than the time of the observations, ~12 hours from the onset of the gamma-ray burst. The character and strength of the

K. A. G. Olsen, B. W. Miller, N. B. Suntzeff, R. A. Schommer

We use CTIO 4-m Mosaic II images taken with the Washington $CM$ and Harris $R$ filters to identify candidate globular clusters in the six major galaxies of the Sculptor group: NGC 45, NGC 55, NGC 247, NGC 254, NGC 300, and NGC 7793. From follow-up spectroscopy with Hydra-CTIO, we find 19 new globular clusters in NGC 55, NGC 247, NGC 253, and NGC 300, bringin

David Elbaz, Emmanuel Moy

Dusty starbursts were more numerous around z~1 than today and appear to be responsible for the majority of cosmic star formation over the Hubble time. We suggest that they represent a common phase within galaxies in general which is triggered by the growth of cosmic structure. We discuss the origin of the luminosity of luminous infrared galaxies at z~1. Are

R. Soria-Ruiz, F. Colomer, J. Alcolea, J. F. Desmurs

On this paper, we present simultaneous VLBA observations of the J=1-0 and J=2-1 rotational lines in the v=1 and v=2 vibrationally excited states of SiO (at 7 and 3 mm wavelengths). We have mapped these four maser lines in the circumstellar envelopes of three AGB stars: IRC +10011, Chi Cyg and TX Cam. We study the relative spatial distribution between these m

F. Lamareille, M. Mouhcine, T. Contini, I. Lewis

We investigate the Luminosity-Metallicity (L-Z) relation in the local universe (z < 0.15) using spectra of 6387 star-forming galaxies extracted from the 2dF Galaxy Redshift Survey. This sample is by far the largest to date used to perform such a study. We distinguish star-forming galaxies from AGNs using &#34;standard&#34; diagnostic diagrams to build a homo

V. S. Imshennik, O. G. Ryazhskaya

We consider an improved rotational mechanism of the explosion of a collapsing supernova. We show that this mechanism leads to two-stage collapse with a phase difference of \sim 5 h. Based on this model, we attempt a new interpretation of the events in underground neutrino detectors on February 23, 1987, related to the supernova SN 1987A.

Tomasz Mizerski

This paper presents results of a fully automated search for multiperiodic RR Lyrae stars in the center of the Galaxy. The search was carried out on OGLE-II database created by means of image subtraction method. I found more than 2700 RR Lyrae stars with about 600 showing various kinds of multiperiodic behavior. Previous OGLE-I database contained only about 2

A. Del Popolo, M. Gambera

We consider the non-radial motions, originating in the outskirts of clusters of galaxies and we show how it may reduce the discrepancy between Cold Dark Matter (CDM) predicted X-ray temperature distribution function of clusters of galaxies and that really observed, so resolving the problem of the X-ray clusters abundance over-production predicted by the CDM

S. Mieske, M. Hilker, L. Infante

The results of the Fornax Compact Object Survey (FCOS) are presented. The FCOS aims at investigating the nature of the Ultra Compact Dwarf galaxies (UCDs) recently discovered in the center of the Fornax cluster (Drinkwater et al. 2000). 280 unresolved objects in the magnitude space covering UCDs and bright globular clusters (18<V<21 mag) were observed spectr

A. Del Popolo, M. Gambera

We calculate the density profiles of virialized halos in the case of structure evolving hierarchically from a scale-free Gaussian delta-field having a power spectrum $P(k)\propto k^n$ in a Omega=1 Universe; we suppose that the initial density contrast profile around local maxima is given by the mean peak profile introduced by Bardeen et al. (1986 hereafter B

G. Chabrier, F. Allard, I. Baraffe, T. Barman

We review our present understanding of the physical properties of substellar objects, brown dwarfs and irradiated or non-irradiated gaseous exoplanets. This includes a description of their internal properties, mechanical structure and heat content, their atmospheric properties, thermal profile and emergent spectrum, and their evolution, in particular as irra

M. Dovciak, S. Bianchi, M. Guainazzi, V. Karas

Narrow spectral features in the 5--6 keV range were recently discovered in the X-ray spectra of a few active galactic nuclei. We discuss the possibility that these features are due to localized spots which occur on the surface of an accretion disc following its illumination by flares. We present detailed line profiles as a function of orbital phase of the sp

P. Eggenberger, C. Charbonnel, S. Talon, G. Meynet

Detailed models of alpha Cen A and B based on new seismological data for alpha Cen B by Carrier & Bourban (2003) have been computed using the Geneva evolution code including atomic diffusion. Taking into account the numerous observational constraints now available for the alpha Cen system, we find a stellar model which is in good agreement with the astrometr

C. R. Mullis, A. Vikhlinin, J. P. Henry, W. Forman

We report measurements of the cluster X-ray luminosity function out to z=0.8 based on the final sample of 201 galaxy systems from the 160 Square Degree ROSAT Cluster Survey. There is little evidence for any measurable change in cluster abundance out to z~0.6 at luminosities less than a few times 10^44 ergs/s (0.5-2.0 keV). However, between 0.6 < z < 0.8 and

K. E. Andersson, G. M. Madejski

Abell 1689 is a galaxy cluster at $z=0.183$ where previous measurements of its mass using various techniques gave discrepant results. We present a new detailed measurement of the mass with the data based on X-ray observations with the European Photon Imaging Camera aboard the XMM-Newton Observatory, determined by using an unparameterized deprojection techniq

Loic Villain, Jose A. Pons, Pablo Cerda-Duran, Eric Gourgoulhon

We investigate the evolution of rigidly and differentially rotating protoneutron stars (PNSs) during the first twenty seconds of their life. We solve the equations describing stationary axisymmetric configurations in general relativity coupled to a finite temperature, relativistic equation of state, to obtain a sequence of quasi-equilibrium configurations de

M. Saralegi-Aranguren, R. Wolak

We study the cohomology properties of the singular foliation $\F$ determined by an action $Φ\colon G \times M\to M$ where the abelian Lie group $G$ preserves a riemannian metric on the compact manifold $M$. More precisely, we prove that the basic intersection cohomology $\lau{\IH}{*}{\per{p}}{\mf}$ is finite dimensional and verifies the Poincaré Duality. Thi

P. Martinetti

Unruh effect states that the vacuum of a quantum field theory on Minkovski space-time looks like a thermal state for an eternal uniformly accelerated observer. Adaptation to the non eternal case causes a serious problem: if the thermalization of the vacuum depends on the lifetime of the observer, then in principle the latest is able to deduce its lifetime fr

E. Iltan

We study the effects of non-universal extra dimensions on the decay widths of the lepton flavor violating processes, $t\to c l_i^- l_j^+ $ and $H^0 \to h^0 (A^0) l_i^- l_j^+$ in the general two Higgs doublet model. We consider that the extra dimensions are accessible to the standard model gauge fields and the new Higgs doublet. We observe that the lepton fla

Max Karlovini, Lars Samuelsson

We present an equation of state for elastic matter which allows for purely longitudinal elastic waves in all propagation directions, not just principal directions. The speed of these waves is equal to the speed of light whereas the transversal type speeds are also very high, comparable to but always strictly less than that of light. Clearly such an equation

Jonathan Sondow

From a global series for the alternating zeta function, we derive an infinite product for pi that resembles the product for $e^γ$ ($γ$ is Euler&#39;s constant) in math.CA/0306008. (An alternate derivation accelerates Wallis&#39;s product by Euler&#39;s transformation.) We account for the resemblance via an analytic continuation of the polylogarithm. An appli

David J. Aldous, Antar Bandyopadhyay

In certain problems in a variety of applied probability settings (from probabilistic analysis of algorithms to statistical physics), the central requirement is to solve a recursive distributional equation of the form X =^d g((ξ_i,X_i),i\geq 1). Here (ξ_i) and g(\cdot) are given and the X_i are independent copies of the unknown distribution X. We survey this

C. Firmani, V. Avila-Reese, G. Ghisellini, A. V. Tutukov

We constrain the isotropic luminosity function (LF) and formation rate of long gamma-ray bursts (GRBs) by fitting models &#39;jointly&#39; to both the observed differential peak flux and redshift distributions. We find evidence supporting an evolving LF, where the luminosity scales as (1+z)^delta with an optimal delta of 1.0\pm 0.2. For a single power-law LF

Abhay Ashtekar, Jonathan Engle, Tomasz Pawlowski, Chris Van Den Broeck

To every axi-symmetric isolated horizon we associate two sets of numbers, $M_n$ and $J_n$ with $n = 0, 1, 2, ...$, representing its mass and angular momentum multipoles. They provide a diffeomorphism invariant characterization of the horizon geometry. Physically, they can be thought of as the `source multipoles&#39; of black holes in equilibrium. These struc

Osvaldo Chandia, Brenno Carlini Vallilo

It is shown that the pure spinor formulation of the heterotic superstring in a generic gravitational and super Yang-Mills background has vanishing one-loop beta functions.

Benjamin D. Greenbaum, Salman Habib, Kosuke Shizume, Bala Sundaram

An analysis of the semiclassical regime of the quantum-classical transition is given for open, bounded, one dimensional chaotic dynamical systems. Environmental fluctuations -- characteristic of all realistic dynamical systems -- suppress the development of fine structure in classical phase space and damp nonlocal contributions to the semiclassical Wigner fu

Marian Aprodu

The gonality conjecture predicts that the gonality of a curve can be read off Koszul cohomology of line bundles of sufficiently large degree. We verify this conjecture for generic curves of odd genus. The even-genus case was previously solved in the joint work arXiv:math.AG/0301261.

Hans-Otto Georgii, Hyun Jae Yoo

The Papangelou intensities of determinantal (or fermion) point processes are investigated. These exhibit a monotonicity property expressing the repulsive nature of the interaction, and satisfy a bound implying stochastic domination by a Poisson point process. We also show that determinantal point processes satisfy the so-called condition $(Σ_λ)$ which is a g

Antonio N. Bernal, Miguel Sánchez

The folk questions in Lorentzian Geometry, which concerns the smoothness of time functions and slicings by Cauchy hypersurfaces, are solved by giving simple proofs of: (a) any globally hyperbolic spacetime $(M,g)$ admits a smooth time function $τ$ whose levels are spacelike Cauchy hyperfurfaces and, thus, also a smooth global splitting $M= \R \times {\cal S}

N. N. Khuri, Andre Martin, Pierre C. Sabatier, Tai Tsun Wu

For a very large class of potentials, $V(\vec{x})$, $\vec{x}\in R^2$, we prove the universality of the low energy scattering amplitude, $f(\vec{k}&#39;, \vec{k})$. The result is $f=\sqrt{\fracπ{2}}\{1/log k)+O(1/(log k)^2)$. The only exceptions occur if $V$ happens to have a zero energy bound state. Our new result includes as a special subclass the case of r

Dirk Siersma, Mihai Tibar

In deformations of polynomial functions one may encounter ``singularity exchange at infinity&#39;&#39; when singular points disappear from the space and produce ``virtual&#39;&#39; singularities which have an influence on the topology of the limit polynomial. We find several rules of this exchange phenomenon, in which the total quantity of singularity turns

Andrey Pototsky, Michael Bestehorn, Uwe Thiele, Domnic Merkt

We consider two stacked ultra-thin layers of different liquids on a solid substrate. Using long-wave theory, we derive coupled evolution equations for the free liquid-liquid and liquid-gas interfaces. Linear and non-linear analyses show that depending on the long-range van-der-Waals forces and the ratio of the layer thicknesses, the system follows different