May 1999 arXiv papers — page 4

Joop Schaye, Tom Theuns, Anthony Leonard, George Efstathiou

Numerical simulations indicate that the smooth, photoionized intergalactic medium (IGM) responsible for the low column density Lyman-alpha forest follows a well defined temperature-density relation. We show that such an equation of state results in a cutoff in the distribution of line widths (b-parameters) as a function of column density (N) for the low colu

Joao Magueijo, Haavard Sandvik, Daniele Steer

We solve numerically the Boltzmann equation describing the evolution of a cosmic string network which contains only loops. In Minkowski space time the equilibrium solution predicted by statistical mechanics is recovered, and we prove that this solution is stable to non-linear perturbations provided that their energy does not exceed the critical energy for th

D. Schiminovich, P. Friedman, C. Martin, P. Morrissey

We report on the first results of the Narrow-band Ultraviolet Imaging Experiment for Wide-field Surveys (NUVIEWS), a sounding rocket experiment designed to map the far-ultraviolet background in four narrow bands. This is the first imaging measurement of the UV background to cover a substantial fraction of the sky. The narrow band responses (145, 155, 161, an

A. Miroshnichenko, Z. Ivezic, D. Vinkovic, M. Elitzur

IR and mm-wave emission from Herbig Ae/Be stars has produced conflicting conclusions regarding the dust geometry in these objects. We show that the compact dimensions of the mm-wave emitting regions are a decisive indication for disks. But a disk cannot explain the spectral energy distribution (SED) unless it is embedded in an extended envelope that (1) domi

E. T. Harlaftis

Observations of the eclipsing dwarf nova IP Peg during outburst reveal metal lines in emission, such as Mg II 4481 A. Analysis using Doppler tomography locates emission of helium and metal lines on the inner Roche lobe of the secondary star. Such multi-line Roche-lobe imaging presents a new tool in mapping the red star's ionization structure.

T. Contini, R. Coziol, S. Considere, E. Davoust

We propose an evolutionary scenario by successive bursts of star formation to reproduce the chemical properties of massive nearby Starburst Nucleus Galaxies (SBNGs). The N/O abundance ratios in SBNGs are 0.2 dex higher than in normal HII regions observed in the disks of late-type spirals. The variation of the N/O ratio as a function of metallicity follows a

Mark Lacy, Steve Rawlings, Gary J. Hill, Andrew J. Bunker

We present the results of optical spectroscopy of two flux-density-limited samples of radio sources selected at frequencies of 38 and 151 MHz in the same region around the North Ecliptic Cap, the 8C-NEC and 7C-III samples respectively. Both samples are selected at flux density levels ~20 times fainter than samples based on the 3C catalogue. They are amongst

Mark Lacy, Mary Elizabeth Kaiser, Gary J. Hill, Steve Rawlings

Further imaging observations of a sample of radio sources in the North Ecliptic Cap are presented and a number of new identifications are made. Using redshifts from spectroscopic data presented in a companion paper (Lacy et al.\ 1999b), the photometric properties of the galaxies in the sample are discussed. It is shown that: (1) out to at least z~0.6 radio g

Giovanni Carraro, Leo Girardi, Cesare Chiosi

Aim of this study is to infer the age of the Galactic Disk by means of the ages of old open clusters, and comment on some recent claims that the Galactic Disk can be older than the Halo. To this purpose, we analyze the Color-Magnitude Diagrams (CMDs) of six very old clusters, namely NGC 188, NGC 6791, Collinder 261, Melotte 66, Berkeley 39 and Berkeley 17, a

C. Chapuis, S. Corbel, P. Durouchoux, W. Mahoney

Two days of observations were conducted at the Palomar Observatory during the nights of 25 and 26 February 1997 with the Hale telescope, in order to search for rapid variability in the near-infrared (NIR) bands J, H, Ks for a selection of eight blazars. With the possible exception of PKS 1156+295, no intraday or day-to-day variability was observed during the

Ian Smail, G. E. Morrison, M. E. Gray, F. N. Owen

We present deep Hubble Space Telescope NICMOS near-infrared and WFPC2 optical imaging of a small region in the core of the distant rich cluster Cl0939+4713 (z=0.41). We compare the optical and near-infrared morphologies of cluster members and find apparent small-scale optical structures within the galaxies which are absent in the near-infrared. We conclude t

Yoshiaki Taniguchi

Seyfert nuclei are typical active galactic nuclei (AGNs) in the local universe, which are thought to be powered by gas accretion onto a supermassive black hole (SMBH). The dynamical effect exerted either by non-axisymmetric gravitational potential (such as a stellar bar) or by interaction with other galaxies has been often considered to cause the efficient g

Sang-Gak Lee

CN and CH band strengths for ten bright red giants in M3 have been measured from archival spectra obtained with the MMT. A CN-CH band strength anticorrelation is confirmed for the program stars together with other stars for which there is published data. This suggests an anticorrelation between carbon and nitrogen abundances with a constant total abundance o

Andrew A. Cole, Eline Tolstoy, John S. Gallagher, John G. Hoessel

We have observed the center of the Local Group dwarf irregular galaxy IC 1613 with WFPC2 aboard the Hubble Space Telescope in the F439W, F555W, and F814W filters. We find a dominant old stellar population (aged ~7 Gyr), identifiable by the strong red giant branch (RGB) and red clump populations. From the (V-I) color of the RGB, we estimate a mean metallicity

David M. Meyer, J. T. Lauroesch

Using the DensePak fiber optic array on the KPNO WIYN telescope, we have obtained high S/N echelle spectra of the Na I D wavelength region toward the central 27" x 43" of the globular cluster M15 at a spatial resolution of 4". The spectra exhibit significant interstellar Na I absorption at LSR velocities of +3 km/s (LISM component) and +68 km/s (

Eric B. Ford, Boris Kozinsky, Frederic A. Rasio

We derive octupole-level secular perturbation equations for hierarchical triple systems, using classical Hamiltonian perturbation techniques. By extending previous work done to leading (quadrupole) order to octupole level (i.e., including terms of order alpha^3, where alpha = a_1/a_2 < 1 is the ratio of semimajor axes) we obtain expressions that are applicab

E. B. Ford, K. J. Joshi, F. A. Rasio, B. Zbarsky

We present a new theoretical analysis of the PSR B1620-26 triple system in the globular cluster M4, based on the latest radio pulsar timing data, which now include measurements of five time derivatives of the pulse frequency. These data allow us to determine the mass and orbital parameters of the second companion completely (up to the usual unknown orbital i

Pieter Maris, Peter. C. Tandy

The masses and decay constants of the light vector mesons $ρ/ω$, $ϕ$ and $K^\star$ are studied within a ladder-rainbow truncation of the coupled Dyson-Schwinger and Bethe-Salpeter equations of QCD with a model 2-point gluon function. The approach is consistent with quark and gluon confinement, reproduces the correct one-loop renormalization group behavior of

M. C. Banuls, I. Scimemi, J. Bernabeu, V. Gimenez

First non-trivial chiral corrections to the magnetic moments of triplet (T) and sextet (S^(*)) heavy baryons are calculated using Heavy Hadron Chiral Perturbation Theory. Since magnetic moments of the T-hadrons vanish in the limit of infinite heavy quark mass (m_Q->infinity), these corrections occur at order O(1/(m_Q Λ_χ^2)) for T-baryons while for S^(*)-bar

R. J. Birgeneau, V. Kiryukhin, Y. J. Wang

The spin-Peierls phase transition in CuGeO_3 has been extensively studied utilizing a variety of experimental techniques. Interpretations of the phase transition behavior vary from tricritical to mean field to Ising critical to XY critical. We show that the behavior in the vicinity of the phase transition of each of the order parameter, the magnetic energy g

N. I. Kochelev

It is shown that the contribution of the instantons to the fragmentation of quarks leads to the appearance of a imaginary part in diagrams of quark-quark scattering at large transfer momentum. The imaginary part comes from the analytical continuation of the instanton amplitudes from Euclidean to Minkowsky space-time and reflects quasiclassical origin of inst

Pavel Etingof, Shlomo Gelaki

In this paper we classify triangular semisimple and cosemisimple Hopf algebras over any algebraically closed field k. Namely, we construct, for each positive integer N, relatively prime to the characteristic of k if it is positive, a bijection between the set of isomorphism classes of triangular semisimple and cosemisimple Hopf algebras of dimension N over k

Ronald E. Cohen, Oguz Gülseren, Russell J. Hemley

The accuracy of equation-of-state formulations is compared for theoretical total energies or experimental pressure-volume measurements for H$_{2}$, Ne, Pt, and Ta. This spans the entire range of compression found for minerals and vo latiles in the Earth. The Vinet equation is found to be most accurate. The origin of the behavior of different equation-of-stat

A. V. Leonidov, D. M. Ostrovsky

Angular asymmetry and momentum disbalance for a pair of particles produced at high energy in central rapidity region are studied. The asymmetry is substantial for small momenta of produced particles but diminishes when they rise.

A. Brandenburg, P. N. Burrows, D. Muller, N. Oishi

We have studied the determination of the running b-quark mass, $m_b(M_Z)$, using $Z^0$ decays into 3 or more hadronic jets. We calculated the ratio of $\geq3$-jet fractions in $e^+e^-\to b\bar{b}$ vs. $e^+e^-\to q_l\bar{q_l}$ ($q_l$ = u or d or s) events at next-to-leading order in perturbative QCD using six different infra-red- and collinear-safe jet-findin

G W Gibbons, P K Townsend

We argue that the Wess-Zumino model with quartic superpotential admits static solutions in which three domain walls intersect at a junction. We derive an energy bound for such junctions and show that configurations saturating it preserve 1/4 supersymmetry.

Conall Kennedy, Andy Wilkins

Couplings between a closed string RR field and open strings are calculated in a system of coincident branes and antibranes of type II theory. The result can be written cleanly using the curvature of the superconnection.

Igor Batalin, Robert Marnelius

Open groups whose generators are in arbitrary involutions may be quantized within a ghost extended framework in terms of a nilpotent BFV-BRST charge operator. Previously we have shown that generalized quantum Maurer-Cartan equations for arbitrary open groups may be extracted from the quantum connection operators and that they also follow from a simple quantu

A. Melchiorri, F. Vernizzi, R. Durrer, G. Veneziano

A recently proposed mechanism for large-scale structure in string cosmology --based on massless axionic seeds-- is further analyzed and extended to the acoustic-peak region. Existence, structure, and normalization of the peaks turn out to depend crucially on the overall evolution of extra dimensions during the pre-big bang phase: conversely, precise cosmic m

ZEUS Collaboration

Correlations between charged particles in deep inelastic ep scattering have been studied in the Breit frame with the ZEUS detector at HERA using an integrated luminosity of 6.4 pb-1. Short-range correlations are analysed in terms of the angular separation between current-region particles within a cone centred around the virtual photon axis. Long-range correl

Scott Pratt

Recursion relations are presented that allow exact calculation of canonical and microcanonical partition functions of degenerate Fermi systems, assuming no explicit two-body interactions. Calculations of the level density, sorted by angular momentum, are presented for Ni-56 are presented. The issue of treating unbound states is also addressed.

Constantine Yannouleas, Uzi Landman

Classes of spontaneous symmetry breaking at zero and low magnetic fields in single quantum dots (QD&#39;s) and quantum dot molecules (QDM&#39;s) are discussed in relation to the ratio R_W between the interelectron Coulomb repulsion and the harmonic confinement, using spin-and-Space unrestricted Hartree-Fock calculations. These include: Wigner crystallization

H. Ahmedov, O. F. Dayi

Non-Abelian fractional supersymmetry algebra in two dimensions is introduced utilizing $U_q(sl(2,\Rcc))$ at roots of unity. Its representations and the matrix elements are obtained. The dual of it is constructed and the corepresentations are studied. Moreover, a differential realization of the non-Abelian fractional supersymmetry generators is given in the g

Yoav Tsori, David Andelman, Michael Schick

We investigate symmetric grain boundaries in a lamellar diblock copolymer system. The form of the interface between two grains strongly depends on the angle $θ$, between the normals of the grains. When this angle is small, the lamellae transform smoothly from one orientation to the other, creating the chevron morphology. As $θ$ increases, a gradual transitio

C. S. Jayanthi, Franck Celestini, Furio Ercolessi, Erio Tosatti

Recent lattice model calculations have suggested that a full-layered crystal surface may undergo, under canonical (particle-conserving) conditions, a preroughening-driven two-dimensional phase separation into two disordered flat (DOF) regions, of opposite order parameter. We have carried out extensive classical molecular dynamics (MD) simulations of the Lenn

Takeshi Nihei

New inflationary solutions to the Einstein equation are explicitly constructed in a simple five-dimensional model with an orbifold extra dimension $S^1/Z_2$. We consider inflation caused by cosmological constants for the five-dimensional bulk and the four-dimensional boundaries. In our solutions the extra dimension is static, and the background metric has a

Michal Chodorowski, Adi Nusser

Given an irrotational (vorticity free) velocity field in real space, we prove that, in the distant observer limit and in the absence of multi-valued zones, the associated velocity field in redshift space is also irrotational. The proof does not rely on any approximation to gravitational dynamics. The result can be particularly useful for the analysis of reds

Jin Min Yang

We examined Z\ell^+\ell^- and Zb\bar b couplings in the minimal supersymmetric model (MSSM) with explicit R-parity violating interactions. We found the top quark L-violating couplings λ&#39;_{i3k} and B-violating couplings λ&#39;&#39;_{3j3} could give significant contributions through the top quark loops. To accomadate the latest R_{\ell} data, λ&#39;_{i3k}

A. N. Das, Jayita Chatterjee

A convergent perturbation method using modified Lang Firsov transformation is developed for a two-site single-polaron system. The method is applicable for the entire range of the electron-phonon coupling strength from the antiadiabatic limit to the intermediate region of hopping. The single-electron energies, oscillator wave functions and correlation functio

K. Tsutsui, T. Tohyama, S. Maekawa

The resonant inelastic x-ray scattering spectrum in insulating cuprates is examined by using the exact diagonalization technique on small clusters in the two-dimensional Hubbard model with second and third neighbor hopping terms. When the incident photon energy is tuned near the Cu K absorption edges, we find that the features of the unoccupied upper Hubbard

Amir H. Fatollahi

The cross section for two bosonic D0-branes is calculated in limit $α&#39;\to 0$. It is found that the cross section shows Regge behavior.

J. Ellis, T. Falk, K. A. Olive, M. Srednicki

Assuming that the lightest supersymmetric particle (LSP) is the lightest neutralino, we present a detailed exploration of neutralino-stau coannihilation channels, including analytical expressions and numerical results. We also include neutralino coannihilations with the selectron and smuon. We evaluate the implications of coannihilations for the cosmological

Ayse Humeyra Bilge, Fatma Ozdemir

The paper is withdrawn due to an error in Section 3.2. The remaining of the results are included in the preprint solv-int/9605004.

Gerhard C. Hegerfeldt, Thorsten Koehler

A few years ago, diffraction of atoms by double slits and gratings was achieved for the first time, and standard optical wave-theory provided an excellent description of the experiments. More recently, diffraction of weakly bound molecules and even clusters has been observed. Due to their size and to possible breakup processes optical wave-theory is no longe

J H Samson

A quantum spin system can be modelled by an equivalent classical system, with an effective Hamiltonian obtained by integrating all non-zero frequency modes out of the path integral. The effective Hamiltonian H_eff(S_i) derived from the coherent-state integral is highly singular: the quasiprobability density exp(-beta H_eff), a Wigner function, imposes quanti

E. Prodan

We show the equivalence between the three approximation schemes for self-interacting (1+1)-D scalar field theories. Based on rigorous results of [1, 2], we are able to prove that the Gaussian approximation is very precise for certain limits of coupling constants. The $λϕ^{4}+σϕ^{2}$ model will be used as a concrete application.

Zhong-Qi Ma, An-Ying Dai

An improved hyperspherical harmonic method for the quantum three-body problem is presented to separate three rotational degrees of freedom completely from the internal ones. In this method, the Schrödinger equation of three-body problem is reduced to a system of linear algebraic equations in terms of the orthogonal bases of functions. As an important example

Alexander A. Vlasov

One-dimensional motion of Sommerfeld sphere in the case of potential barrier is numerically investigated. The effect of classical tunneling is found out - Sommerfeld sphere overcomes the barrier and finds itself in the forbidden, from classical point of view, area.

V. K. Magas, Cs. Anderlik, L. P. Csernai, F. Grassi

Freeze out of particles across three dimensional space-time hypersurface is discussed in a simple kinetic model. The final momentum distribution of emitted particles, for freeze out surfaces with space-like normal, shows a non-exponential transverse momentum spectrum. The slope parameter of the $p_t$ distribution increases with increasing $p_t$, in agreement

F. R. Xu, R. Wyss, P. M. Walker

Nuclear shapes and odd-nucleon blockings strongly influence the odd-even differences of nuclear masses. When such effects are taken into account, the determination of the pairing strength is modified resulting in larger pair gaps. The modified pairing strength leads to an improved self-consistent description of moments of inertia and backbending frequencies,

Mieke De Cock, Mark Fannes, Pascal Spincemaille

We propose to analyse the statistical properties of a sequence of vectors using the spectrum of the associated Gram matrix. Such sequences arise e.g. by the repeated action of a deterministic kicked quantum dynamics on an initial condition or by a random process. We argue that, when the number of time-steps, suitably scaled with respect to $\hbar$, increases

Siva Athreya

We establish a monotonicity property in the space variable for the solutions of an initial boundary value problem concerned with the parabolic partial differential equation connected with super-Brownian motion.

Wellington de Melo, Alberto Pinto

Given $C^2$ infinitely renormalizable unimodal maps $f$ and $g$ with a quadratic critical point and the same bounded combinatorial type, we prove that they are $C^{1+α}$ conjugate along the closure of the corresponding forward orbits of the critical points, for some $α>0$.

Kevin Pilgrim

We show that the absolute Galois group acts faithfully on the set of Hubbard trees. Hubbard trees are finite planar trees, equipped with self-maps, which classify postcritically finite polynomials as holomorphic dynamical systems on the complex plane. We establish an explicit relationship between certain Hubbard trees and the trees known as ``dessins d&#39;e

John W. Milnor

A key point in Douady and Hubbard&#39;s study of the Mandelbrot set $M$ is the theorem that every parabolic point $c\ne 1/4$ in $M$ is the landing point for exactly two external rays with angle which are periodic under doubling. This note will try to provide a proof of this result and some of its consequences which relies as much as possible on elementary co

Daniel Allcock

We simplify the usual statement of the Torelli theorem for complex Enriques surfaces, by means of a lattice-theoretic trick. This allows easy proofs of several known results, which previously required intricate arithmetic arguments. The main new result is that the moduli space has contractible universal cover.

Denis V. Juriev

The interactive game theoretical approach to the description of perception processes is proposed. The subject is treated formally in terms of a new class of the verbalizable interactive games which are called the perception games. An application of the previously elaborated formalism of dialogues and verbalizable interactive games to the visual perception al

Peter Ebenfelt

In this paper, we consider real hypersurfaces $M$ in $\Bbb C^3$ (or more generally, 5-dimensional CR manifolds of hypersurface type) at uniformly Levi degenerate points, i.e. Levi degenerate points such that the rank of the Levi form is constant in a neighborhood. We also require the hypersurface to satisfy a certain second order nondegeneracy condition (cal

Svetlana D. Tyurina

Vassiliev&#39;s knot invariants can be computed in different ways but many of them as Kontsevich integral are very difficult. We consider more visual diagram formulas of the type Polyak-Viro and give new diagram formula for the two basic Vassiliev invariant of degree 4.

Svetlana D. Tyurina

Vassiliev&#39;s knot invariants can be computed in different ways but many of them as Kontsevich integral are very difficult. We consider more visual diagram formulas of the type Polyak-Viro and give new diagram formula for the two basic Vassiliev invariant of degree 4.

Svetlana D. Tyurina

Vassiliev&#39;s knot invariants can be computed in different ways but many of them as Kontsevich integral are very difficult. We consider more visual diagram formulas of the type Polyak-Viro and give new diagram formula for the two basic Vassiliev invariant of degree 4

Peter Brinkmann

Bestvina and Handel have found an effective algorithm that determines whether a given homeomorphism of an orientable, possibly punctured surface is pseudo-Anosov. We present a software package in Java that realizes this algorithm for surfaces with one puncture. Moreover, the package allows the user to define homeomorphisms in terms of Dehn twists, and in the

Karsten Keller

New insights into the combinatorial structure of the Mandelbrot set are given by `Correspondence&#39; and `Translation&#39; Principles both conjectured and partially proved by E. Lau and D. Schleicher. We provide complete proofs of these principles and discuss results related to them. Note: The `Translation&#39; and `Correspondence&#39; Principles given earl

Sylvain Wolf

The central charge in the N=2 Super-Yang-Mills theory plays an essential role in the work of Seiberg and Witten as it gives the mass spectrum of the BPS states of the quantum theory. Our aim in this note is to present a direct computation of this central charge for the leading order (in a momentum expansion) of the effective action. We will consider the N=2

Ruggero Ferrari, Pietro Antonio Grassi, Andrea Quadri

A purely algebraic method is devised in order to recover Slavnov-Taylor identities (STI), broken by intermediate renormalization. The counterterms are evaluated order by order in terms of finite amplitudes computed at zero external momenta. The evaluation of the breaking terms of the STI is avoided and their validity is imposed directly on the vertex functio

Dan Radu Grigore

We present a new point of view on the quantization of the gravitational field, namely we use exclusively the quantum framework of the second quantization. More explicitly, we take as one-particle Hilbert space, $H_{graviton}$ the unitary irreducible representation of the Poincaré group corresponding to a massless particle of helicity 2 and apply the second q

Kenichi Horie, Hitoshi Miyazaki, Izumi Tsutsui

We study quantum caustics in $d$-dimensional systems with quadratic Lagrangians. Based on Schulman&#39;s procedure in the path-integral we derive the transition amplitude on caustics in a closed form for generic multiplicity $f$, and thereby complete the previous analysis carried out for the maximal multiplicity case $f=d$. Multiplicity dependence of the cau

A. Inopin, G. S. Sharov

We scrutinized hadronic Regge trajectories in a framework of two different models --- string and potential. Our results are compared with broad spectrum of existing theoretical quark models and all experimental data from PDG98. It was recognized that Regge trajectories for mesons and baryons are not straight and parallel lines in general in the current reson

S. Willenbrock

I present an overview of standard-model top-quark physics at the Fermilab Tevatron. Topics discussed include the top-quark mass, weak interaction, strong interaction, and rare decays.

Tesla E. Jeltema, Marc Sher

In multiple-universe models, the constants of nature may have different values in different universes. Agrawal, Barr, Donoghue and Seckel have pointed out that the Higgs mass parameter, as the only dimensionful parameter of the standard model, is of particular interest. By considering a range of values of this parameter, they showed that the Higgs vacuum exp

E. Norrbin, T. Sjöstrand

We have refined a model for charm fragmentation at hadron colliders. This model can also be applied to the photoproduction of charm. We investigate the effect of fragmentation on the distribution of produced charm quarks. The drag effect is seen to produce charm hadrons that are shifted in rapidity in the direction of the beam remnant. We also study the impo

Carl E. Carlson

Hard, or high transverse momentum, pion photoproduction can be a tool for probing the parton structure of the beam and target. We discuss the perturbative and soft processes that contribute, and show how regions where perturbative processes dominate can give us the parton structure information. Polarized initial states are needed to get information on polari

J. -M. Virey, E. Tuğcu, P. Taxil

The effects of Scalar Leptoquarks in various channels have been analysed for the HERA collider and also for an eventual new $ep$ machine running at higher energies. We emphasize the relevance of polarized beams.

M. Anselmino, M. Boglione, F. Murgia

A consistent phenomenological approach to the computation of transverse single spin asymmetries in inclusive hadron production is presented, based on the assumed generalization of the QCD factorization theorem to the case in which quark intrinsic motion is taken into account. New k_T and spin dependent quark distribution and fragmentation functions are consi

Ken Sasaki, Tsuneo Uematsu

We investigate the spin structure of the virtual photon beyond the leading order in QCD. The first moment of the virtual photon spin structure function $g_1^γ(x,Q^2,P^2)$ with QCD effects turns out to be non-vanishing in contrast to the real photon case. Numerical analysis for virtual as well as real photon case is presented.

A. A. Pivovarov

Results of evaluating the leading order $α_s$ corrections to the correlator of tensor currents in pure gluodynamics are presented. These corrections to the parton result for the correlator are not large numerically that allows one to use perturbation theory for the analysis of the resonance spectrum within the sum rules method.

C. P. Burgess

The description of neutrino propagation through a fluctuating medium is summarized. Fluctuation-Dissipation-Theorem arguments relate microscopic fluctuations to thermodynamic quantities, allowing these to be very generally studied in astrophysical environments. Fluctuation-induced modifications to neutrino oscillations have been studied in detail within the

K. Ogure, J. Sato

We study the end-point of the Electroweak phase transition using the auxiliary mass method. The end point is $m_H\sim40$ (GeV) in the case $m_t=0$ (GeV) and strongly depends on the top quark mass. A first order phase transition disappears at $m_t\sim 160$ (GeV). The renormalization effect of the top quark is significant.

Nikolaos Kidonakis

I present some results for the next-to-next-to-leading order expansions of the resummed cross sections for heavy quark and direct photon production near threshold in hadronic collisions.

Vadim Bednyakov, Amand Faessler, Sergey Kovalenko

The paper has been withdrawn by the authors for modification.

Brien C. Nolan

Withdrawn; conclusion that the singularity is strong is incorrect.

Sanjay Jhingan, Giulio Magli

The present analytical understanding on the nature of the singularities which form at the endstate of gravitational collapse of massive fluid bodies (&#34;stars&#34;) is reviewed. Special emphasis is devoted to the issue of physical reasonability of the models.

D. V. Alekseevsky, V. Cortes

The variation of Hodge structure of a Calabi-Yau 3-fold induces a canonical Kähler metric on its Kuranishi moduli space, known as the Weil-Petersson metric. Similarly, special pseudo Kähler manifolds correspond to certain (abstract) variations of Hodge structure which generalize the above example. We give the classification of homogeneous special pseudo Kähl

G. E. Crooks, B. Ostrovsky, Y. Bar-Yam

We investigate the internal structure of a polymer during collapse from an expanded coil to a compact globule. Collapse is more probable in local regions of high curvature, so a smoothing of the fractal polymer structure occurs that proceeds systematically from the shortest to the longest length scales. A proposed universal scaling relationship is tested by

M. G. Zimmermann, R. Toral, O. Piro, M. San Miguel

We introduce a stochastic partial differential equation capable of reproducing the main features of spatiotemporal intermittency (STI). Additionally the model displays a noise induced transition from laminarity to the STI regime. We show by numerical simulations and a mean-field analysis that for high noise intensities the system globally evolves to a unifor

T. Fukui

A two-dimensional lattice model for d-wave superconductor with chiral symmetry is studied. The field theory at the band center is shown to be in the universality class of U(2n)/O(2n) and U(2n) nonlinear sigma model for the system with broken and unbroken time-reversal symmetry, respectively. Vanishing of the beta function implies extended states at the band

A. Arenas, A. Diaz-Guilera, C. J. Perez, F. Vega-Redondo

We propose a general scenario to analyze social and economic changes in modern environments. We illustrate the ideas with a model that incorporating the main trends is simple enough to extract analytical results and, at the same time, sufficiently complex to display a rich dynamic behavior. Our study shows that there exists a macroscopic observable that is m

N. I. Lundin, L. Y. Gorelik, R. I. Shekhter, V. S. Shumeiko

We show that transport through a superconducting quantum point contact biased at subgap voltages is strongly affected by a microwave field. The subgap current is increased by several orders of magnitude. Quantum interference among resonant scattering events involving photon absorption is reflected as an oscillating structure in the I-V curve. We also discuss

A. A. Maradudin, I. Simonsen, T. A. Leskova, E. R. Mendez

We present a method for generating numerically a one-dimensional random surface, defined by the equation $x_3 = \zx$, that suppresses single-scattering processes in the scattering of light from it within a specified range of scattering angles. Rigorous numerical calculations of the scattering of light from surfaces generated by this approach show that the si

K. Jonason, P. Nordblad, F. C. Montenegro

The diluted Ising antiferromagnet, Fe_{0.31}Zn_{0.69}F_{2}, has been investigated by dynamic susceptibility measurements in zero and and finite applied dc-fields. In zero field, there is a para- to antiferromagnetic phase transition at $T_{N} \approx {20.0 K}$, followed by a dramatic slowing down of the dynamics at low temperatures. The latter described by a

Rosa Ramirez, Thorsten Poeschel, Nikolai V. Brilliantov, Thomas Schwager

We perform a dimension analysis for colliding viscoelastic spheres to show that the coefficient of normal restitution $ε$ depends on the impact velocity g as ε=1-γ_1g^{1/5}+γ_2g^{2/5}\mp..., in accordance with recent findings. We develop a simple theory to find explicit expressions for coefficients γ_1 and γ_2. Using these and few next expansion coefficients

Zvonko Glumac, Katarina Uzelac

We examine the order of the phase transition in the Potts model by using the graph representation for the partition function, which allows treating a non-integer number of Potts states. The order of transition is determined by the analysis of the shape of the graph-weight probability distribution. The approach is illustrated on special cases of the one-dimen

A. G. Souza Filho, P. T. C. Freire, J. M. Sasaki, I. Guedes

We have investigated the behavior of the PbZr(0.94}Ti(0.06)O3 Raman spectra as a function of Hydrostatic pressures. The new structural phases were identified based on previous works performed in PZT system with different Ti concentrations at room- and high pressures. We showed that PbZr(0.94}Ti(0.06}O3 exhibits a rich phase sequence up to 3.7 GPa: rhombohedr

K. Kato, S. Todo, K. Harada, N. Kawashima

Ground-state magnetic properties of the diluted Heisenberg antiferromagnet on a square lattice are investigated by means of the quantum Monte Carlo method with the continuous-time loop algorithm. It is found that the critical concentration of magnetic sites is independent of the spin size S, and equal to the two-dimensional percolation threshold. However, th

V. S. Babichenko

An instability of the quasi-1D Luttinger liquid associated with the metal - insulator transition is considered. The homogeneous metal ground state of this liquid is demonstrated to be unstable and the charge-density wave arises in the system. The wavevector of this wave has nonzero component both along the direction of the chains and in the perpendicular dir

E. A. Jagla

We study the phase diagram of a system of spherical particles interacting in three dimensions through a potential consisting of a strict hard core plus a linear repulsive shoulder at larger distances. The phase diagram (obtained numerically, and analytically in a limiting case) shows anomalous properties that are similar to those observed in water. Specifica

Mikio Nakahara, Tomoya Isoshima, Kazushige Machida, Shin-ichiro Ogawa

Bose-Einstein condensation in alkali atoms has materialized quite an interesting system, namely a condensate with a spin degree of freedom. In analogy with the A-phase of the superfluid $^3$He, numerous textures with nonvanishing vorticity have been proposed. In the present paper, interesting properties of such spin textures are analyzed. We propose a remark

H. B. Chan, R. C. Ashoori, L. N. Pfeiffer, K. W. West

We explore the characteristics of equilibrium tunneling of electrons from a 3D electrode into a high mobility 2D electron system. For most 2D Landau level filling factors, we find that tunneling can be characterized by a single, well-defined tunneling rate. However, for spin-polarized quantum Hall states (nu = 1, 3 and 1/3) tunneling occurs at two distinct r

G. J. L. Gerhardt, M. Frichembruder, F. B. Rizzato, S. R. Lopes

In this work we investigate the validity limits of the modulational approximation as a method to describe the nonlinear interaction of conservative wave fields. We focus on a nonlinear Klein-Gordon equation and suggest that the breakdown of the approximation is accompanied by a transition to regimes of spatiotemporal chaos.

Hugo Touchette, Seth Lloyd

Fundamental limits on the controllability of physical systems are discussed in the light of information theory. It is shown that the second law of thermodynamics, when generalized to include information, sets absolute limits to the minimum amount of dissipation required by open-loop control. In addition, an information-theoretic analysis of closed-loop contr