December 1998 arXiv papers — page 13

A. Wehner, J. T. Wheeler

Biconformal gauging of the conformal group has a scale-invariant volume form, permitting a single form of the action to be invariant in any dimension. We display several 2n-dim scale-invariant polynomial actions and a dual action. We solve the field equations for the most general action linear in the curvatures for a minimal torsion geometry. In any dimensio

Nikolaos Irges

We argue that in certain models with family symmetries the implementation of the alignment mechanism for the supression of the flavor changing neutral currents requires mass matrices with holomorphic zeros in the down quark sector. Holomorphic zeros typically open flat directions that potentially spoil the uniqueness of the supersymmetric vacuum. We then pre

Thomas P. Branson, V. G. J. Rodgers, Takeshi Yasuda

We continue to explore the possibility that the graviton in two dimensions is related to a quadratic differential that appears in the anomalous contribution of the gravitational effective action for chiral fermions. A higher dimensional analogue of this field might exist as well. We improve the defining action for this diffeomorphism tensor field and establi

Robert de Mello Koch, Kyungho Oh, Radu Tatar

We show that a system of parallel D3 branes near a conifold singularity can be mapped onto an intersecting configuration of orthogonal branes in type IIA string theory. Using this brane configuration, we analyze the Higgs moduli space of the associated field theory. The dimension of the Higgs moduli space is computed from a geometrical analysis of the conifo

D. A. Demir, A. Masiero, O. Vives

We analyze CP violation in supersymmetric extensions of the Standard Model with heavy scalar fermions of the first two generations. Neglecting intergenerational mixing in the sfemion mass matrices and thus considering only chargino, charged Higgs and W--boson diagrams we show that it is possible to fully account for CP violation in the kaon system even in th

L. N. Lipatov

The duality symmetry of the Hamiltonian and integrals of motion for Reggeon interactions in multicolour QCD is formulated as an integral equation for the wave function of compound states of $n$ reggeized gluons. In particular the Odderon problem in QCD is reduced to the solution of the one-dimensional Schrödinger equation. The Odderon Hamiltonian is written

W. Genovese, Miguel A. Munoz

Recent developments in the analysis of Langevin equations with multiplicative noise (MN) are reported. In particular, we: (i) present numerical simulations in three dimensions showing that the MN equation exhibits, like the Kardar-Parisi-Zhang (KPZ) equation both a weak coupling fixed point and a strong coupling phase, supporting the proposed relation betwee

A. I. Karanikas, C. N. Ktorides, N. G. Stefanis, S. M. H. Wong

We consider a four-point process, associated with a wide-angle elastic scattering of two off-mass-shell spin-1/2 matter particles, in a non-abelian gauge theory. On the basis of a worldline approach, which reverts the functional to a path-integral description of the system, we factorize an eikonal (``soft'') subsector of the full theory and calculate

S. Cassemiro F. F., Victor O. Rivelles

We discuss the relation between canonical and Schrodinger quantization of the CGHS model. We also discuss the situation when background charges are added to cancel the Virasoro anomaly. New physical states are found when the square of the background charges vanishes.

A. D. Martin, M. G. Ryskin, A. Stasto

We analyse the data for the proton structure function $F_2$ over the entire $Q^2$ domain, including especially low $Q^2$, in terms of perturbative and non-perturbative QCD contributions. The small distance configurations are given by perturbative QCD, while the large distance contributions are given by the vector dominance model and, for the higher mass $q \

Joan Simón

T-duality realized on D-brane effective actions is studied from a pure worldvolume point of view. It is proved that invariance in the form of the Dirac-Born-Infeld and Wess-Zumino terms fixes the T-duality transformations of the NS-NS and R-R background fields, respectively. The analysis is extended to uncover the mapping of global symmetries of the correspo

F. Rami, P. Crochet, R. Dona, B. de Schauenburg

Directed sideward flow of light charged particles and intermediate mass fragments was measured in different symmetric reactions at bombarding energies from 90 to 800 AMeV. The flow parameter is found to increase with the charge of the detected fragment up to Z = 3-4 and then turns into saturation for heavier fragments. Guided by simple simulations of an anis

P. Singha Deo, F. M. Peeters, V. A. Schweigert

Using the non-linear Ginzburg-Landau (GL) eqs. type I superconducting disks of finite radius ($R$) and thickness ($d$) are studied in a perpendicular magnetic field. Depending on $R$ and $d$, first or second order phase transitions are found for the normal to superconducting state. For sufficiently large $R$ several transitions in the superconducting phase a

J. Blümlein, A. Tkabladze

The target mass corrections to the twist-2 contributions of the spin-dependent structure functions are calculated using operator product expansion in lowest order in QCD. The influence of such corrections to the different relations between the structure functions is considered.

M. Scattoni, C. Grimaldi, L. Pietronero

We show that, in contrast with the usual electron-phonon Migdal-Eliashberg theory, the critical temperature Tc of an isotropic s-wave nonadiabatic superconductor is strongly reduced by the presence of diluted non-magnetic impurities. Our results suggest that the recently observed Tc-suppression driven by disorder in K3C60 [Phys. Rev. B vol.55, 3866 (1997)] a

Ziqiang Wang, Shanhui Xiong

The tunneling into the {\em bulk} of a 2D electron system (2DES) in strong magnetic field is studied near the integer quantum Hall transitions. We present a nonperturbative calculation of the tunneling density of states (TDOS) for both Coulomb and short-ranged electron-electron interactions. In the case of Coulomb interaction, the TDOS exhibits a 2D quantum

D. W. Berry, H. M. Wiseman, Zhong-Xi Zhang

The standard technique for measuring the phase of a single mode field is heterodyne detection. Such a measurement may have an uncertainty far above the intrinsic quantum phase uncertainty of the state. Recently it has been shown [H. M. Wiseman and R. B. Killip, Phys. Rev. A 57, 2169 (1998)] that an adaptive technique introduces far less excess noise. Here we

Kamiokande Collaboration

A total of 614 upward through-going muons of minimum energy 1.6 GeV are observed by Super-Kamiokande during 537 detector live days. The measured muon flux is 1.74+/-0.07(stat.)+/-0.02(sys.)x10^{-13}cm^{-2}s^{-1}sr^{-1} compared to an expected flux of 1.97+/-0.44(theo.)x10^{-13}cm^{-2}s^{-1}sr^{-1}. The absolute measured flux is in agreement with the predicti

J. F. Corney, G. J. Milburn, Weiping Zhang

A Bose-Einstein condensate may be used to make precise measurements of weak forces, utilizing the macroscopic occupation of a single quantum state. We present a scheme which uses a condensate in a double well potential to do this. The required initial state of the condensate is discussed, and the limitations on the sensitivity due to atom collisions and exte

I. Antoniadis, C. Bachas

If the fundamental type-I string scale is of the order of few TeV, the problem of the gauge hierarchy is that of understanding why some dimensions transverse to our brane-world are so large. The technical aspect of this problem, as usually formulated, is `why quantum corrections do not modify drastically the masses and other parameters of the Standard Model&

Z. F. Ezawa

We analyze bilayer quantum Hall ferromagnets, whose underlying symmetry group is SU(4). Spin-pseudospin coherence develops spontaneously when the total electron density is low enough. Quasiparticles are CP^3 skyrmions. One skyrmion induces charge modulations on both of the two layers. At the filling factor$ν=2/m$ one elementary excitation consists of a pair

Steven R. White, D. J. Scalapino

As the number of legs n of an n-leg, t-J ladder increases, density matrix renormalization group calculations have shown that the doped state tends to be characterized by a static array of domain walls and that pairing correlations are suppressed. Here we present results for a t-t'-J model in which a diagonal, single particle, next-near-neighbor hopping t

Narciso Benitez, Tom Broadhurst, Rychard Bouwens, Joseph Silk

A substantial population of high redshift early-type galaxies is detected in very deep UBVRIJHK images towards the HDF-South. Four elliptical profile galaxies are identified in the redshift range z=1-2, all with very red SEDs, implying ages of >2 Gyrs for standard passive evolution. We also find later type IR-luminous galaxies at similarly high redshift, (10

S. Lafortune, P. Winternitz, C. R. Menyuk

Group theoretical methods are used to study the equations describing χ^{(2)}:χ^{(2)} cascading. The equations are shown not to be integrable by inverse scattering techniques. On the other hand, these equations do share some of the nice properties of soliton equations. Large families of explicit analytical solutions are obtained in terms of elliptic functions

S. Lekic, S. Galamic, Z. Rajilic

A new method for finding solutions of the nonlinear Shrödinger equation is proposed. Comutative multiplicative group of the nonlinear transformations, which operate on stationary localized solutions, enables a consideration of fractal subspaces in the solution space, stability and deterministic chaos. An increase of the transmission rate at the optical fiber

K. Yabana, G. F. Bertsch

As part of a general study of the time-dependent local density approximation (TDLDA), we here report calculations of optical activity of chiral molecules. The theory automatically satisfies sum rules and the Kramers-Kronig relation between circular dichroism and optical rotatory power. We find that the theory describes the measured circular dichroism of the

Hasan Gümral

Exact, degenerate two-forms on time-extended space R X M which are invariant under the unsteady, incompressible fluid motion on 3D region M are introduced. The equivalence class up to exact one-forms of each potential one-form is splitted by the velocity field. The components of this splitting corresponds to Lagrangian and Eulerian conservation laws for heli

Noga Alon, Miklós Bóna, Joel Spencer

Answering a question of Wilf, we show that if $n$ is sufficiently large, then one cannot cover an $n \times p(n)$ rectangle using each of the $p(n)$ distinct Ferrers shapes of size $n$ exactly once. Moreover, the maximum number of pairwise distinct, non-overlapping Ferrers shapes that can be packed in such a rectangle is only $Θ(p(n)/ \log n).$

C. Roger, V. Ovsienko

We classify nontrivial deformations of the standard embedding of the Lie algebra $\Vect(S^1)$ of smooth vector fields on the circle, into the Lie algebra~$\PD(S^1)$ of pseudodifferential symbols on $S^1$. This approach leads to deformations of the central charge induced on $\Vect(S^1)$ by the canonical central extension of $\PD(S^1)$. As a result we obtain a

Miklós Bóna, Daniel A. Spielman

We constructively prove that the partially ordered set of finite permutations ordered by deletion of entries contains an infinite antichain.

O. Debarre

We prove Lefschetz type theorems for cohomology groups and Picard groups of degeneracy loci for vector bundle maps. We also treat the case of antisymmetric maps.

Joseph D. Masters

Let $M$ be a once-punctured torus bundle over $S^1$ with monodromy $h$. We show that, under certain hypotheses on $h$, "most" Dehn-fillings of $M$ (in some cases all but finitely many) are virtually $\mathbb{Z}$-representable. We apply our results to show that surgeries on the figure-eight knot with even numerator are virtually $\mathbb{Z}$-represent

S. Gonorazky, F. A. Schaposnik, G. Silva

Using the natural curvature invariants as building blocks in a superfield construction, we show that the use of a symmetric trace is mandatory if one is to reproduce the square root structure of the non-Abelian Dirac-Born-Infeld Lagrangian in the bosonic sector. We also discuss the BPS relations in connection with our supersymmetry construction.

Andre Lukas, Burt A. Ovrut, Daniel Waldram

In these lectures, we present cosmological vacuum solutions of Horava-Witten theory and discuss their physical properties. We begin by deriving the five-dimensional effective action of strongly coupled heterotic string theory by performing a reduction, on a Calabi-Yau three-fold, of M-theory on S1/Z2. The effective theory is shown to be a gauged version of f

L. Clavelli

The CDF inclusive jet transverse energy cross section at 1.8 TeV suggests anomalous behavior at both low and high transverse energies. In addition the scaled ratio of the 0.63 TeV to 1.8 TeV data lies significantly below the standard model prediction and suggests structure not attributable to standard model processes. These anomalies are in line with what wo

S. Narison, G. M. Shore, G. Veneziano

The theory of the `proton spin' effect proposed in our earlier papers is extended to include the chiral SU(3) symmetry breaking and flavour mixing induced by non-vanishing quark masses in QCD. The theoretical basis is the derivation of exact, unified Goldberger-Treiman (GT) relations valid beyond the chiral limit. The observed suppression in the flavour

Paolo Gambino

Recent calculations of the two-loop electroweak effects enhanced by powers of the top mass have been implemented in the main electroweak libraries and have an important effect on the indirect determination of the Higgs mass MH. I briefly review the main results of these calculations and discuss in detail the residual uncertainties and their impact on the glo

S. V. Goloskokov

In this report we calculate the cross section and $A_{ll}$ asymmetry for the diffractive $J/Ψ$ leptoproduction. We study dependences of the asymmetry on the structure of the Pomeron-proton coupling

Chen Gang, Liu Lianshou, Gao Yanmin

It is pointed out that in doing the factorial moment analysis with non-integer partition $M$ of phase space, the influence of the phase-space variation of two- (or more-) particle correlations has to be considered carefully. In this paper this problem is studied and a systematic method is developed to minimize this influence. The efficiency and self-consiste

Kevin Cahill

In the physical vacuum of QCD, the energy density of light-quark fields strongly coupled to slowly varying gluon fields can be negative, and so a condensate of pairs of quarks and antiquarks of nearly opposite momenta forms which breaks chiral symmetry, confines quarks, and makes gluons massive.

M. N. Chernodub, M. I. Polikarpov, A. I. Veselov

We investigate the dual superconductor hypothesis in finite-temperature SU(2) lattice gluodynamics in the Spatial Maximal Abelian gauge. This gauge is more physical than the ordinary Maximal Abelian gauge due to absence of non-localities in temporal direction. We show numerically that in the Spatial Maximal Abelian gauge the probability distribution of the a

Ken D. Olum, J. J. Blanco-Pillado

We have performed a lattice field theory simulation of cusps in Abelian-Higgs cosmic strings. The results are in accord with the theory that the portion of the strings which overlaps near the cusp is released as radiation. The radius of the string cores which must touch to produce the evaporation is approximately $r = 1$ in natural units. In general, the mod

L. Fernandez-Jambrina, L. M. Gonzalez-Romero

In this paper a new formalism based on exterior differential systems is derived for perfect-fluid spacetimes endowed with an abelian orthogonally transitive G2 group of motions acting on spacelike surfaces. This formulation allows simplifications of Einstein equations and it can be applied for different purposes. As an example a singularity-free metric is re

Fernando C. Lombardo

We study the quatum to classical transition process in the context of quantum field theory. Extending the influence functional formalism of Feynman and Vernon, we study the decoherence process for self-interacting quantum fields in flat space. We also use this formalism for arbitrary geometries to analyze the quantum to classical transition in quantum gravit

M. Hortacsu, B. C. Lutfuoglu

We show spurious effects in perturbative calculations due to different orderings of inhomogeneous terms while computing corrections to Green functions for two different metrics. These effects are not carried over to physically measurable quantities like the renormalized value of the vacuum expectation value of the stress-energy tensor.

Babak Hodjat, Makoto Amamiya

User interfaces that adapt their characteristics to those of the user are referred to as adaptive interfaces. We propose Adaptive Agent Oriented Software Architecture (AAOSA) as a new way of designing adaptive interfaces. AAOSA is a new approach to software design based on an agent-oriented architecture. In this approach agents are considered adaptively comm

Babak Hodjat, Christopher J. Savoie, Makoto Amamiya

A new approach to software design based on an agent-oriented architecture is presented. Unlike current research, we consider software to be designed and implemented with this methodology in mind. In this approach agents are considered adaptively communicating concurrent modules which are divided into a white box module responsible for the communications and

Babak Hodjat, Makoto Amamiya

In [N. A. Baas, Emergence, Hierarchies, and Hyper-structures, in C.G. Langton ed., Artificial Life III, Addison Wesley, 1994.] a general framework for the study of Emergence and hyper-structure was presented. This approach is mostly concerned with the description of such systems. In this paper we will try to bring forth a different aspect of this model we fe

John Watrous

It is not currently known if quantum Turing machines can efficiently simulate probabilistic computations in the space-bounded case. In this paper we show that space-bounded quantum Turing machines can efficiently simulate a limited class of random processes: random walks on undirected graphs. By means of such simulations, it is demonstrated that the undirect

Dima Mozyrsky, Vladimir Privman

We consider incorporation of particle detachment in Smoluchowski model of colloidal growth. Two approaches are considered, utilizing phenomenological rate equation and exact large-time results. Our main conclusion is that the value of the large-time diffusing particle concentration at the aggregate surface is the only parameter needed to describe the added e

J. Fabian, S. Das Sarma

Spin relaxation of conduction electrons in metals is significantly influenced by the Fermi surface topology. Electrons near Brillouin zone boundaries, special symmetry points, or accidental degeneracy lines have spin flip rates much higher than an average electron. A realistic calculation and analytical estimates show that these regions dominate the spin rel

Sergei Nechaev

The lectures review the state of affairs in modern branch of mathematical physics called probabilistic topology. In particular we consider the following problems: (i) We estimate the probability of a trivial knot formation on the lattice using the Kauffman algebraic invariants and show the connection of this problem with the thermodynamic properties of 2D di

Einat Aharonov, David Sparks

We model two-dimensional systems of granular aggregates confined between two planes and demonstrate that at a critical grain volume fraction an abrupt rigidity transition occurs. This transition is observed both in static and shear tests. The grain volume fraction at which the transition occurs, $ν_c$, decreases with increasing friction between the grains. D

F. Y. Wu, H. Kunz

The problem of a restricted random walk on graphs which keeps track of the number of immediate reversal steps is considered by using a transfer matrix formulation. A closed-form expression is obtained for the generating function of the number of n-step walks with r reversal steps for walks on any graph. In the case of graphs of a uniform valence, we show tha

F. Y. Wu, C. King, W. T. Lu

The Tutte polynomial is a generalization of the chromatic polynomial of graph colorings. Here we present an extension called the rooted Tutte polynomial, which is defined on a graph where one or more vertices are colored with prescribed colors. We establish a number of results pertaining to the rooted Tutte polynomial, including a duality relation in the cas

K. Klauck, A. Schadschneider

Recently it has been shown that the zero-energy eigenstate -- corresponding to the stationary state -- of a stochastic Hamiltonian with nearest-neighbour interaction in the bulk and single-site boundary terms, can always be written in the form of a so-called matrix-product state. We generalize this result to stochastic Hamiltonians with arbitrary, but finite

Shie-Jie Xiong, G. N. Katomeris, S. N. Evangelou

In the absence of magnetic field or spin-orbit coupling the one-parameter scaling theory predicts localization of all states in two-dimensional (2D) disordered systems, for any amount of disorder. However, a 2D metallic phase has been recently reported in high mobility Si-MOS and GaAs-based materials without magnetic field. We study numerically a recently pr

Toshio Aoyagi, Masaki Nomura

Little is known theoretically about the associative memory capabilities of neural networks in which information is encoded not only in the mean firing rate but also in the timing of firings. Particularly, in the case that the fraction of active neurons involved in memorizing patterns becomes small, it is biologically important to consider the timings of firi

Martin Ahr, Michael Biehl, Robert Urbanczik

Equilibrium states of large layered neural networks with differentiable activation function and a single, linear output unit are investigated using the replica formalism. The quenched free energy of a student network with a very large number of hidden units learning a rule of perfectly matching complexity is calculated analytically. The system undergoes a fi

Christophe Texier, Alain Comtet

We show that the distribution of the time delay for one-dimensional random potentials is universal in the high energy or weak disorder limit. Our analytical results are in excellent agreement with extensive numerical simulations carried out on samples whose sizes are large compared to the localisation length (localised regime). The case of small samples is a

M. Capone, S. Ciuchi, C. Grimaldi

The crossover from quasi free electron to small polaron in the Holstein model for a single electron is studied by means of both exact and self-consistent calculations in one dimension and on an infinite coordination lattice, in order to understand the role of dimensionality in such a crossover. We show that a small polaron ground-state occurs when both stron

P. Zupanovic, A. Bjelis, S. Barisic

The solution to the long standing problem of the cohesion of organic chain compounds is proposed. We consider the tight-binding dielectric matrix with two electronic bands per chain, determine the corresponding hybridized collective modes, and show that three among them are considerably softened due to strong dipole-dipole and monopole-dipole interactions. B

N. Shibata, H. Tsunetsugu

The finite-temperature density-matrix renormalization-group method is applied to the one-dimensional Kondo lattice model near half filling to study its thermodynamics. The spin and charge susceptibilities and entropy are calculated down to T=0.03t. We find two crossover temperatures near half filling. The higher crossover temperature continuously connects to

Steven H. Simon

The composite fermion picture has had a remarkable number of recent successes both in the description of the fractional quantized Hall states and in the description on the even denominator Fermi liquid like states. In this review we give an introductory account of the Chern-Simons fermion theory, focusing on the description of the even denominator states as

G. Moeller, V. Dobrosavljevic, A. E. Ruckenstein

A two-site cluster generalization of the Hubbard model in large dimensions is examined in order to study the role of short-range spin correlations near the metal-insulator transition (MIT). The model is mapped to a two-impurity Kondo-Anderson model in a self-consistently determined bath, making it possible to directly address the competition between the Kond

Matthew P. A. Fisher

These introductory lecture notes describe recent results on novel Mott insulating phases which are "descendents" of superconductors - obtained by "quantum disordering". After a brief overview of quantum magnetism, attention is focussed on the spin-liquid phase of the two-leg Hubbard ladder and the "nodal liquid" - a descendent of the

You-Hua Chu, Adeline Caulet, Marcos Montes, Nino Panagia

The supernova SN 1978K has been noted for its lack of emission lines broader than a few thousand km/s since its discovery in 1990. Modeling of the radio spectrum of the peculiar SN 1978K indicates the existence of HII absorption along the line of sight. To determine the nature of this absorbing region, we have obtained a high-dispersion spectrum of SN 1978K

James W. Wadsley, Craig J. Hogan, Scott F. Anderson

Observations of resolved HeII Lyman alpha absorption in spectra of two QSO's suggest that the epoch of helium ionization occurred at z~3. Proximity zones in the spectra of the quasars (z=3.18, 3.285) at 304 A resemble Stromgren spheres, suggesting that the intergalactic medium is only singly ionized in helium. We present models of the proximity effect wh

L. -S. The, M. F. El Eid, B. S. Meyer

We present a comprehensive study of s-process nucleosynthesis in 15, 20, 25, and 30 $\msun$ stellar models having solar-like initial composition. The stars are evolved up to ignition of central neon with a 659 species network coupled to the stellar models. In this way, the initial composition from one burning phase to another is consistently determined, espe

Eric Gawiser, Douglas Finkbeiner, Andrew Jaffe, Joanne C. Baker

The Wavelength-Oriented Microwave Background Analysis Team (WOMBAT) is constructing microwave skymaps which will be more realistic than previous simulations. Our foreground models represent a considerable improvement: where spatial templates are available for a given foreground, we predict the flux and spectral index of that component at each place on the sk

Ethan T. Vishniac

Dynamos in astrophysical disks are usually explained in terms of the standard alpha-omega mean field dynamo model where the local helicity generates a radial field component from an azimuthal field. The subsequent shearing of the radial field gives rise to exponentially growing dynamo modes. There are several problems with this model. The exponentiation time

W. F. Bottke,, D. C. Richardson, P. Michel, S. Love

Until recently, most asteroids were thought to be solid bodies whose shapes were determined largely by collisions with other asteroids. It now seems that many asteroids are little more than rubble piles, held together by self-gravity; this means that their shapes may be strongly distorted by tides during close encounters with planets. Here we report on numer

Christopher R. Gelino, M. Marley, D. Stephens, J. Lunine

The atmospheres of extrasolar giant planets are modeled with various effective temperatures and gravities, with and without clouds. Bond albedos are computed by calculating the ratio of the flux reflected by a planet (integrated over wavelength) to the total stellar flux incident on the planet. This quantity is useful for estimating the effective temperature

Ulisse Munari, Lina Tomasella

Internal kinematics, spectroscopic binaries and galactic motion are investigated for the trapezium system BD+00.1617 (which lies at the heart of the young open cluster Bochum 2) by means on 73 high resolution Echelle+CCD spectra secured over the period 1994-98. Two of the three O-type member stars are found to be binaries on close and highly eccentric orbits

T. Storchi-Bergmann, C. Winge, Martin J. Ward, A. S. Wilson

We present results of near--IR long-slit spectroscopy in the J and K bands of the Seyfert 2 galaxies NGC 2110 and Circinus, investigating the gaseous distribution, excitation, reddening and kinematics. In NGC 2110, the emission line ratio [FeII]/Pa beta increases towards the nucleus (to ~ 7). The nuclear [Fe II]1.257 (microns) and Pa beta lines are broader (

Anatoli Vankov

Baryon asymmetry of the observed universe as a clue to a resolution of dark matter, galaxy formation and other standard model problems.

S. Phillipps, J. B. Jones, R. M. Smith, W. J. Couch

Recent studies have demonstrated that many galaxy clusters have luminosity functions (LFs) which are steep at the faint end. However, it is equally clear that not all clusters have identical LFs. In this paper we explore whether the variation in LF shape correlates with other cluster or environmental properties.

Witold Maciejewski, Linda S. Sparke

Inner regions of barred disk galaxies often include asymmetrical, small-scale central features, some of which are best described as secondary bars. Because orbital timescales in the galaxy center are short, secondary bars are likely to be dynamically decoupled from the main kiloparsec-scale bars. We found that non-chaotic multiply-periodic particle orbits ca

J. B. Jones, S. Phillipps, J. M. Schwartzenberg, Q. A. Parker

We describe a new, deep photographic survey of the Virgo Cluster which uses multiple exposures on Tech Pan film with the United Kingdom Schmidt Telescope to probe the dwarf population to fainter surface brightness limits than previous surveys. We have identified galaxies having sizes (>= 3 arcsec scale length) and surface brightnesses (<= 24.5 R mag arcsec^-

G. Efstathiou, S. L. Bridle A. N. Lasenby, M. P. Hobson, R. S. Ellis

We perform a combined likelihood analysis of the latest cosmic microwave background anisotropy data and distant Type 1a Supernova data of Perlmutter etal (1998a). Our analysis is restricted to cosmological models where structure forms from adiabatic initial fluctuations characterised by a power-law spectrum with negligible tensor component. Marginalizing ove

S Capozziello, G Iovane

A sort of gravitational waveguide effect in cosmology could explain some anomalous phenomena which cannot be understood by the current gravitational lensing models as the existence of &#34;twins&#34; objects with similar spectra and redshifts posed on the sky with large angular distance. Furthermore, the huge luminosities of quasars could be explained using

Tsutomu T. Takeuchi, Hiroyuki Hirashita, Kouji Ohta, Takashi G. Hattori

Infrared Imaging Surveyor (IRIS) is a satellite which will be launched in the beginning of 2003. One of the main purposes of the IRIS mission is an all-sky survey at far-infrared (FIR) with a flux limit much deeper than that of IRAS. In order to examine the performance of the survey, we estimated the FIR galaxy counts in four (50, 70, 120, and 150 $μ$m) band

Eduard Thommes

Due to the invention of new powerful instruments in the recent past (e.g. 10m class telescopes) high redshift galaxies are no longer a curiosity. High redshift young star forming galaxies can be effectively discriminated from the much more abundant foreground galaxies by their special spectral properties: a prominent break at the Lyman limit (i.e. a complete

Raul Jimenez, Amancio Friaca, James Dunlop, Roberto Terlevich

It has recently been argued that single-collapse high-redshift models for elliptical galaxy formation can be rejected because they predict large numbers of very red galaxies at intermediate redshifts which are not seen in deep optical-infrared surveys. We argue, however, that this conclusion is premature since, while much effort has been invested in refining

Naoki Seto, Jun&#39;ichi Yokoyama

If primordial fluctuation is Gaussian distributed, higher-order cumulants of the cosmic fields reflect nonlinear mode coupling and provide useful information of gravitational instability picture of structure formation. We show that their expected deviation (sample variance) from the universal values is nonvanishing even in linear theory in the case where obs

Lionel Siess, Mario Livio

We study the response of the structure of an asymptotic giant branch (AGB) star to the accretion of a brown dwarf or planet in its interior. In particular, we examine the case in which the brown dwarf spirals-in, and the accreted matter is deposited at the base of the convective envelope and in the thin radiative shell surrounding the hydrogen burning shell.

Priyamvada Natarajan

In this letter we examine the role of the first supernovae in proto-galaxies, their role in feedback and the consequences for disk assembly. Extending the picture proposed by Dekel & Silk (1986), we argue that energetic supernovae winds can expel baryons from all proto-galaxies with varying degrees of efficiency. The fraction of baryons retained and hence av

Narciso Benitez, Tom Broadhurst, Piero Rosati, Fred Courbin

We detect a distant cluster of galaxies centered on the QSO lens and luminous X-ray source AXJ2019+112, a.k.a. ``The Dark Cluster&#39;&#39; (Hattori et al 1997). Using deep V,I Keck images and wide-field K_s imaging from the NTT, a tight red sequence of galaxies is identified within a radius of 0.2 h^{-1} Mpc of the known z=1.01 elliptical lensing galaxy. Th

V. M. Pudalov, G. Brunthaler, A. Prinz, G. Bauer

We found that the conductivity of the two-dimensional electron system in Si-MOS structures is limited to a maximum value, G_{max}, as either density increases or temperature decreases. This value G_{max} is weakly disorder dependent and ranging from 100 to 140 e^2/h for samples whose mobilities differ by a factor of 4.

J. Schaffner-Bielich, J. Randrup

The SU(3) extension of the linear sigma model is employed to elucidate the effect of including strangeness on the formation of disoriented chiral condensates. By means of a Hartree factorization, approximate dispersion relations for the 18 scalar and pseudoscalar meson species are derived and their self-consistent solution makes it possible to trace out the

U. Schneider, P. Lunkenheimer, R. Brand, A. Loidl

Dielectric spectroscopy covering more than 18 decades of frequency has been performed on propylene carbonate in its liquid and supercooled-liquid state. Using quasi-optic submillimeter and far-infrared spectroscopy the dielectric response was investigated up to frequencies well into the microscopic regime. We discuss the alpha-process whose characteristic ti

L. Faddeev, Antti J. Niemi

Recently we have proposed a set of variables for describing the infrared limit of four dimensional SU(2) Yang-Mills theory. here we extend these variables to the general case of four dimensional SU(N) Yang-Mills theory. We find that the SU(N) connection A decomposes according to irreducible representations of SO(N-1) and the curvature two-form F is related t

A. Dedes, S. Moretti

We study the processes `gluon gluon -> squark antisquark CP-odd Higgs&#39; within the theoretical framework of the Supergravity (SUGRA) inspired Minimal Supersymmetric Standard Model (MSSM) at the leading order (LO) in perturbative Quantum Chromo-Dynamics (QCD). Other than constituting a novel production mechanism of the neutral, CP-odd Higgs particle, they

Robert M. Kerr, Axel Brandenburg

Numerical evidence for a finite-time singularity in ideal 3D magnetohydrodynamics (MHD) is presented. The simulations start from two interlocking magnetic flux rings with no initial velocity. The magnetic curvature force causes the flux rings to shrink until they come into contact. This produces a current sheet between them. In the ideal compressible calcula

M. Rainer

The properties of the effective sigma-model for D-dimensional Einstein gravity based on multidimensional geometries is analyzed. Besides pure geometry, additional minimally coupled scalars and (p+2)-forms are considered which yield an extended target space after reduction to the effective D_0-dimensional geometry. In any case the target space is a homogeneou

Igor R. Klebanov, Arkady A. Tseytlin

In a recent paper we considered the type 0 string theories, obtained from the ten-dimensional closed NSR string by a GSO projection which excludes space-time fermions, and studied the low-energy dynamics of N coincident D-branes. This led us to conjecture that the four-dimensional SU(N) gauge theory coupled to 6 adjoint massless scalars is dual to a backgrou

Alakabha Datta, Patrick. J. O&#39;Donnell, Sandip Pakvasa, Xinmin Zhang

We study flavor changing processes $Υ\to B/{\bar B} X_s$ and $J/ψ\to D/{\bar D} X_u$ in the B factories and the Tau-Charm factories. In the standard model, these processes are predicted to be unobservable, so they serve as a probe of the new physics. We first perform a model independent analysis, then examine the predictions of models; such as TopColor model

Marc Mezard, Giorgio Parisi

We propose a first principle computation of the equilibrium thermodynamics of simple fragile glasses starting from the two body interatomic potential. A replica formulation translates this problem into that of a gas of interacting molecules, each molecule being built of m atoms, and having a gyration radius (related to the cage size) which vanishes at zero t

B. Legras, B. Villone, U. Frisch

It is shown by perturbation techniques and numerical simulations that the inverse cascade of kink-antikink annihilations, characteristic of the Kolmogorov flow in the slightly supercritical Reynolds number regime, is halted by the dispersive action of Rossby waves in the beta-plane approximation. For beta tending to zero, the largest excited scale is proport

B. Stefanski

An explicit calculation is performed to check all the tangent bundle gravitational couplings of Dirichlet branes and Orientifold planes by scattering $q$ gravitons with a $p+1$ form Ramond-Ramond potential in the world-volume of a $D(p+2q)$-brane. The structure of the D-brane Wess-Zumino term in the world-volume action is confirmed, while a different O-plane