May 2001 arXiv papers — page 12

V. Podzorov, C. H. Chen, M. E. Gershenson, S-W. Cheong

By using the dark-field real-space imaging technique of transmission electron microscopy (TEM), we have observed slow 200 A-scale fluctuations of charge-ordered (CO) phase in mixed-valent manganites under a strong electron beam irradiation. In addition to these unusual fluctuations of the CO phase, we observed the switching-type fluctuations of electrical re

N. V. Priezjev, Robert A. Pelcovits

We investigate the behavior of disclination loops in the vicinity of the first order nematic-isotropic transition in the Lebwohl-Lasher and related models. We find that two independent measures of the transition temperature, the free energy and the distribution of disclination line segments, give essentially identical values. We also calculate the distributi

David Hughes, Maya Paczuski

We introduce a sandpile model where, at each unstable site, all grains are transferred randomly to downstream neighbors. The model is local and conservative, but not Abelian. This does not appear to change the universality class for the avalanches in the self-organized critical state. It does, however, introduce long-range spatial correlations within the met

C. Hess, C. Baumannn, U. Ammerahl, B. Büchner

We have measured the thermal heat conductivity kappa of the compounds Sr_14Cu_24O_41 and Ca_9La_5Cu_24O_41 containing doped and undoped spin ladders, respectively. We find a huge anisotropy of both, the size and the temperature dependence of kappa which we interpret in terms of a very large heat conductivity due to the magnetic excitations of the one-dimensi

J. K. Krüger, J. Petersson, J. Baller, M. Henkel

Based on experimental evidences we present a phenomenological description of the thermal glass transition as a dynamical phase transition. Different susceptibilities calculated on the basis of this description are in good qualitative agreement with experimental data. As an essential feature this novel view of the glass transition reflects the kinetic as well

I. A. Zaliznyak, J. M. Tranquada, R. Erwin, Y. Moritomo

We studied the melting of the charge order in the half-doped tetragonal perovskite La1.5Sr0.5CoO4 by elastic neutron scattering. We found that diffuse peaks, corresponding to the breathing-type modulation of oxygen positions in the CoO6 octahedra, disappear above Tc = 825(27) K. This melting of the diffuse superstructure is reversible (no change in the corre

K. Kunc, I. Loa, K. Syassen, R. K. Kremer

The effect of pressure on optical phonon frequencies of MgB$_2$ has been calculated using the frozen-phonon approach based on a pseudopotential method. Grüneisen parameters of the harmonic mode frequencies are reported for the high-frequency zone-center $E_{2g}$ and $B_{1g}$ and the zone-boundary $E_{2u}$ and $B_{2u}$ modes at $A$. Anharmonic effects of phon

Erik Koch, Stefan Goedecker

We define Wannier functions for interacting systems, and show that the results on the localization of the Wannier functions for non-interacting systems carry over to the Wannier functions for interacting systems. In addition we demonstrate that the characterization of metals and insulators by the decay properties of their respective density matrices does not

Daniel Sanchez-Portal, Julian D. Gale, Alberto Garcia, Richard M. Martin

The Si(557)-Au surface, containing monatomic Au wires parallel to the steps, has been proposed as an experimental realization of an ideal one-dimensional metal. In fact, recent photoemission experiments on this system (Nature 402, 504 (1999)) found two peaks that were interpreted in terms of the spin-charge separation in a Luttinger liquid. Our first-princip

Zs. Gulacsi, I. Orlik

We are reporting a new non-Fermi liquid type normal phase that has a well defined Fermi energy, but without showing any non-regularity in the momentum distribution function in the whole momentum space, the sharp Fermi momentum concept being undefinable. The system contains a natural built in gap that is visible in the physical properties of the system at non

S. M. M. Virtanen, T. P. Simula, M. M. Salomaa

Considering a moving vortex line in a dilute atomic Bose-Einstein condensate within time-dependent Hartree-Fock-Bogoliubov-Popov theory, we derive a criterion for the quasiparticle excitations to follow the vortex core rigidly. The assumption of adiabaticity, which is crucial for the validity of the stationary self-consistent theories in describing such time

Evgeni Penev, Peter Kratzer, Matthias Scheffler

We present a first-principles analysis of the strain renormalization of the cation diffusivity on the GaAs(001) surface. For the example of In/GaAs(001)-c(4x4) it is shown that the binding of In is increased when the substrate lattice is expanded. The diffusion barrier ΔE(e) has a non-monotonic strain dependence with a maximum at compressive strain values (e

J. M. Rubi, A. Perez-Madrid

We present a general formalism able to derive the kinetic equations of polymer dynamics. It is based on the application of nonequilibrium thermodynamics to analyze the irreversible processes taking place in the conformational space of the macromolecules. The Smoluchowski equation results from the analysis of the underlying diffusion process in that space wit

G. Hechenblaikner, S. A. Morgan, E. Hodby, O. M. Marago

In this paper we give a theoretical description of resonant coupling between two collective excitations of a Bose condensed gas (BEC) on, or close, to a second harmonic resonance. Using analytic expressions for the quasi-particle wavefunctions we show that the coupling between quadrupole modes is strong, leading to a coupling time of a few milliseconds (for

T. Theenhaus, R. Schilling, A. Latz, M. Letz

We investigate the dynamics of a fluid of dipolar hard spheres in its liquid and glassy phase, with emphasis on the microscopic time or frequency regime. This system shows rather different glass transition scenarios related to its rich equilibrium behavior which ranges from a simple hard sphere fluid to a long range ferroelectric orientational order. In the

A. N. Lavrov, Yoichi Ando, Seiki Komiya, I. Tsukada

We present a study of the magnetic susceptibility in carefully detwinned La_{2-x}Sr_{x}CuO_4 single crystals in the lightly-doped region (x=0-0.03), which demonstrates a remarkable in-plane anisotropy of the spin system. This anisotropy is found to persist after the long-range antiferromagnetic (AF) order is destroyed by hole doping, suggesting that doped ho

H. Tou, H. Ikejiri, Y. Maniwa, T. Ito

This paper has been withdrawn by the authors, because of serious experimental problems.

James S. Ulvestad, Luis C. Ho

We have carried out an analysis of the radio and optical properties of a statistical sample of 45 Seyfert galaxies from the Palomar spectroscopic survey of nearby galaxies. We find that the space density of bright galaxies (-22 mag <= M_{B_T} <= -18 mag) showing Seyfert activity is (1.25 +/- 0.38) X 10^{-3} Mpc^{-3}, considerably higher than found in other S

Peter R. McCullough, Robert A. Benjamin

We report the discovery of a extremely narrow, extremely linear, ionized filament. The filament is 2.5 degrees long and has an H$α$ surface brightness of 0.5 rayleighs. The filament is approximately ``Y&#39;&#39; shaped. The widest separation of the two diagonal segments is 5 arcminutes. We discuss four possible origins for this feature: (1) an extremely low

John Scalo, J. Craig Wheeler

According to recent models, gamma-ray bursts apparently explode in a wide variety of ambient densities ranging from ~ 10^{-3} to 30 cm^{-3}. The lowest density environments seem, at first sight, to be incompatible with bursts in or near molecular clouds or with dense stellar winds and hence with the association of gamma-ray bursts with massive stars. We argu

Jonathan Williams

Massive stars form in clusters within self-gravitating molecular clouds. The size scale of these clusters is sufficiently large that non-thermal, or turbulent, motions of the gas must be taken into account when considering their formation. Millimeter wavelength radio observations of the gas and dust in these clouds reveal a complex, self-similar structure th

Edward A. Ajhar, John L. Tonry, John P. Blakeslee, Adam G. Riess

We present Hubble Space Telescope measurements of surface brightness fluctuations (SBF) distances to early-type galaxies that have hosted Type Ia supernovae (SNIa). The agreement in the relative SBF and SNIa multicolor light curve shape and delta-m_15 distances is excellent. There is no systematic scale error with distance, and previous work has shown that S

Igor V. Igumenshchev, Ramesh Narayan

We present three-dimensional numerical magnetohydrodynamic simulations of radiatively inefficient spherical accretion onto a black hole. The simulations are initialized with a Bondi flow, and with a weak, dynamically unimportant, large-scale magnetic field. The magnetic field is amplified as the gas flows in. When the magnetic pressure approaches equipartiti

Cecilia Clementi, Marco Pettini

Integrability, one of the classic issues in galactic dynamics and in general in celestial mechanics, is here revisited in a Riemannian geometric framework, where newtonian motions are seen as geodesics of suitable ``mechanical&#39;&#39; manifolds. The existence of constants of motion that entail integrability is associated with the existence of Killing tenso

Eli Dwek

The extragalactic background light (EBL), exclusive of the cosmic microwave background, consists of the cumulative radiative output from all energy sources in the universe since the epoch of recombination. Most of this energy is released at ultraviolet and optical wavelengths. However, observations show that a significant fraction of the EBL falls in the 10

A. Staude, A. D. Schwope, R. Schwarz

Based on high-resolution optical spectroscopy in the blue and the near infra-red spectral range, we derived velocity images (Doppler tomograms) of the mass-donating secondary star and the accretion stream of the long-period eclipsing polar V1309 Ori (RX J0515.41+0104.6). Combined with HST-spectroscopy of high time resolution and optical photometry we were ab

Julien Lesgourgues, Andrew R. Liddle

We use a wide range of observations to constrain cosmological models possessing a significant asymmetry in the lepton sector, which offer perhaps the best chance of reconciling a critical-density Universe with current observations. The simplest case, with massless neutrinos, fails to fit many experimental data and does not lead to an acceptable model. If the

L. S. Pilyugin

The low-luminosity dwarf irregular galaxies are considered. The oxygen abundances in HII regions of dwarf irregular galaxies were recalculated from published spectra through the recently suggested P - method. It has been found that the metallicity of low-luminosity dwarf irregular galaxies, with a few exceptions, correlates well with galaxy luminosity. The d

A. Del Popolo, M. Gambera

We study the effect of non-radial motions on the mass function, the VDF and on the shape of clusters of galaxies using the model introduced in Del Popolo & Gambera (1998a,b; 1999). The mass function of clusters, obtained using the quoted model, is compared with the statistical data by Bahcall & Cen (1992) and Girardi et al. (1998), while the VDF is compared

A. Del Popolo

In this paper I extend the results of Ahmad & Cohen (1973), regarding the study of the probability distribution of the stochastic force in homogeneous gravitational systems, to inhomogeneous gravitational ones. To this aim, I study the stochastic force distribution using N-body realizations of Plummer&#39;s spherically symmetric models. I find that the stoch

M. Tosi, E. Sabbi, M. Bellazzini, A. Aloisi

We present HST photometry of the resolved stellar population in the dwarf irregular galaxy NGC 1705. The galaxy has been observed with both WFPC2 and NICMOS, and successful images have been obtained in the F555W, F814W, F110W and F160W bands. The optical fields cover most of the galaxy, while the infrared field (NIC2) maps only its central regions. The optic

H. J. Voelk

Particle acceleration in the dynamically evolving environment of Supernova Remnants is discussed in the framework of a genuinely time-dependent nonlinear theory, assuming spherical symmetry. As a consequence the dependence of injection on the angle between shock normal and external magnetic field direction requires a renormalisation of the calculated particl

Stanislav Boldyrev

We formulate a solvable model that describes generation and saturation of mean magnetic field in a dynamo with kinetic helicity, in the limit of large magnetic Prandtl number. This model is based on the assumption that the stochastic part of the velocity field is Gaussian and white in time (the Kazantsev-Kraichnan ensemble), while the regular part describing

M. Catelan, R. T. Rood, F. R. Ferraro

We study the globular clusters M3 and Palomar 3 as a &#34;second parameter (2ndP) pair,&#34; showing that: i) M3 has a surprisingly strong *internal* 2ndP; ii) The dispersion in mass on the Pal 3 horizontal branch (HB) is intrinsically very small, leading to the most apparent differences in HB morphology between M3 and Pal 3; iii) Ignoring the difference in

T. Shahbaz, J. Casares

Rejected by MNRAS due to irregularites in the text. The first author is solely resposible for this.

Wei Ku, W. E. Pickett, R. T. Scalettar, A. G. Eguiluz

A sharp collective charge excitation is predicted in MgB$_2$ at $\sim2.5eV$ for $q$ perpendicular to the boron layers, based on an all-electron analysis of the dynamical density response within time-dependent density functional theory. This novel excitation, consisting of coherent charge fluctuation between Mg and B sheets, induces an abrupt plasma edge in t

M. Vitvitska, A. A. Klypin, A. V. Kravtsov, R. H. Wechsler

We propose a new explanation for the origin of angular momentum in galaxies and their dark halos, in which the halos obtain their spin through the cumulative acquisition of angular momentum from satellite accretion. In our model, the build-up of angular momentum is a random walk process associated with the mass assembly history of the halo&#39;s major progen

Axel Pelster, Florian Weissbach

We evaluate perturbatively the density matrix in the low-temperature limit and thus the ground-state wave function of the anharmonic oscillator up to second order in the coupling constant. We then employ Kleinert&#39;s variational perturbation theory to determine the ground-state wave function for all coupling strengths.

Jose L. Cereceda

By using an alternative, equivalent form of the CHSH inequality and making extensive use of the experimentally testable property of physical locality we determine the 64 different Bell-type inequalities (each one involving four joint probabilities) into which Hardy&#39;s nonlocality theorem can be cast. This allows one to identify all the two-qubit correlati

Alex Kaivarainen

A basically new Hierarchic theory, general for solids and liquids (Kaivarainen, 2001, 2000, 1995, 1992), has been briefly described and illustrated by computer simulations on examples of water and ice. Full description of theory and its numerous applications are presented in series of articles at the arXiv of Los-Alamos (see http://arXiv.org/abs/physics/0102

Susan Kurien, Katepalli R. Sreenivasan

Two recent publications [V. Yakhot, Phys. Rev. E {\bf 63}, 026307, (2001) and R.J. Hill, J. Fluid Mech. {\bf 434}, 379, (2001)] derive, through two different approaches that have the Navier-Stokes equations as the common starting point, a set of steady-state dynamic equations for structure functions of arbitrary order in hydrodynamic turbulence. These equati

Vladimir A. Kazakov

We review recent results in the matrix model approach to the 2-d non-critical string theory compactified in time, in the phase of condensation of the world sheet vortices (above the Berezinski-Kosterlitz-Thouless phase transition). This phase is known to describe strings on the 2-d black hole background, due to the conjecture of V.Fateev, A. and Al.Zamolodch

Tohru Eguchi, Nicholas P. Warner, Sung-Kil Yang

We consider the compactification of the IIA string to (1+1) dimensions on non-compact 4-folds that are ALE fibrations. Supersymmetry requires that the compactification include 4-form fluxes, and a particular class of these models has been argued by Gukov, Vafa and Witten to give rise to a set of perturbed superconformal coset models that also have a Landau-G

Axel Pelster, Konstantin Glaum

We review different approaches to the graphical generation of the tadpole-free Feynman diagrams of the self-energy and the one-particle irreducible four-point function. These are needed for calculating the critical exponents of the euclidean multicomponent scalar phi^4-theory with renormalization techniques in d=4-epsilon dimensions.

Z. Nussinov

Here we examine O(n) systems with arbitrary two spin interactions (of unspecified range) within a general framework. We shall focus on translationally invariant interactions. In the this case, we determine the ground states of the $O(n \ge 2)$ systems. We further illustrate how one may establish Peierls bounds for many Ising systems with long range interacti

A. De Rujula

The observations suggest that $γ$-ray bursts (GRBs) are produced by jets of relativistic cannonballs (CBs), emitted in supernova (SN) explosions. The CBs, reheated by their collision with the SN shell, emit radiation and Doppler-boost it to the few-hundred keV energy of the GRB&#39;s photons. Chaperoning the GRB, there should be an intense flux of neutrinos

Yu-xin Liu, Dong-feng Gao, Hua Guo

With the global color symmetry model (GCM) being extended to finite chemical potential, the density dependence of the bag constant, the total energy and the radius of a nucleon, as well as the quark condensate in nuclear matter are investigated. A maximal nuclear matter density for the existence of the bag with three quarks confined within is obtained. The c

T. Frederico, A. Delfino, Lauro Tomio, V. S. Timoteo

We show how to derive fixed-point Hamiltonians in quantum mechanics from a proposed renormalization group invariance approach that relies in a subtraction procedure at a given energy scale. The scheme is valid for arbitrary interactions that originally contain point-like singularities (as the Dirac-delta and/or its derivatives). One example of diagonalizatio

Andrew P. Billyard, William N. Sajko

We examine generalizations of the five-dimensional canonical metric by including a dependence of the extra coordinate in the four-dimensional metric. We discuss a more appropriate way to interpret the four-dimensional energy-momentum tensor induced from the five-dimensional space-time and show it can lead to quite different physical situations depending on t

Narayan Banerjee, Somasri Sen, Naresh Dadhich

It is shown that the conclusion regarding the existence of a scalar hair for a black hole in a nonminimally coupled self interacting scalar tensor theory can be drawn from the that for a scalar field minimally coupled to gravity by means of a conformal transformation.

W. K. Neils, D. J. Van Harlingen

We propose and implement a direct experimental test for subdominant superconducting phases with broken time-reversal symmetry in d-wave superconductors. The critical current of 45-degree asymmetric grain boundary junctions are shown to be extremely sensitive to the predicted onset of a complex order parameter at (110)-surfaces and near magnetic impurities. M

Andrey L. Pankratov

The behavior of a Josephson flux-flow oscillator in the presence of both bias current and magnetic field fluctuations has been studied. To derive the equation for slow phase dynamics in the limit of small noise intensity the Poincare method has been used. Both the form of spectral line and the linewidth of the flux-flow oscillator have been derived exactly o

D. J. J. Farnell, M. L. Ristig

In this article, the correlated basis-function (CBF) method is applied for the first time to the quantum spin-half {\it XY} model on the linear chain, the square lattice, and the simple cubic lattice. In this treatment of the quantum spin-half {\it XY} model a Jastrow ansatz is utilised to approximate the ground-state wave function. Results for the ground-st

R. K. Bhaduri, Diptiman Sen

This is a comment on the work of Kolomeisky et al., Phys. Rev. Lett. 85, 1146 (2000). We point out that they are using the wrong form of the energy functional for one-dimensional fermions. We point out two possible forms of the energy functional, both of which can be derived from first principles but using different methods. One is obtained from the collecti

A. K. Raychaudhuri, Ayan Guha, I. Das, R. Rawat

We present the results of a study of specific heat on a single crystal of Pr$_{0.63}$Ca$_{0.37}$MnO$_3$ performed over a temperature range 3K-300K in presence of 0 and 8T magnetic fields. An estimate of the entropy and latent heat in a magnetic field at the first order charge ordering (CO) transition is presented. The total entropy change at the CO transitio

Zhen Ye

Wave localization is a ubiquitous phenomenon. It refers to situations that transmitted waves in scattering media are trapped in space and remain confined in the vicinity of the initial site until dissipated. Based on a scaling analysis, the localization behavior in two and three dimensions is studied. It is shown that the localization transition is possible

M. A. Fuentes, C. Tessone, H. S. Wio, R. Toral

We have analyzed the phenomenon of stochastic resonance in a system driven by non Gaussian noises. We have considered both white and colored noises. In the latter case we have obtained a consistent Markovian approximation that enables us to get quasi-analytical results for the signal-to-noise ratio. As the system departs from Gaussian behavior, our main find

Ofer Lahav

Observational tests for the homogeneity of the Universe on large scales are reviewed. Assuming the Cosmological Principle we then estimate cosmological parameters by joint analysis of the Cosmic Microwave Background, Supernovae Ia, peculiar velocities, cluster abundance and redshift surveys. Our results are consistent with results obtained by other groups, s

Ofer Lahav

Analyses of various cosmological probes, including the latest Cosmic Microwave Background anisotropies, the 2dF Galaxy Redshift Survey and Cepheid-calibrated distance indicators suggest that the age of expansion is $13 \pm 3$ Gyr. We discuss some statistical aspects of this estimation, and we also present results for joint analysis of the latest CMB and Ceph

Ofer Lahav

Galaxy redshift surveys and Cosmic Microwave Background experiments are undertaken with larger and larger teams, in a fashion reminiscent of particle physics experiments and the human genome projects. We discuss the role of young researchers, the issue of multiple authorship, and ways to communicate effectively in teams of tens to hundreds of collaborators.

Xinzhong Chen, Hongling Rao, Edward A. Spiegel

We use the one-dimensional steady version of the equations derived in paper I to compute the structure of shock waves. The agreement with experiment is good, especially when we retain the experimental value of the Prandtl number adopted in II.

Xinzhong Chen, Hongling Rao, Edward A. Spiegel

The equations of fluid dynamics developed in paper I are applied to the study of the propagation of ultrasound waves. There is good agreement between the predicted propagation speed and experimental results for a wide range of Knudsen numbers.

Xinzhong Chen, Hongling Rao, Edward A. Spiegel

We describe an asymptotic procedure for deriving continuum equations from the kinetic theory of a simple gas. As in the works of Hilbert, of Chapman and of Enskog, we expand in the mean flight time of the constituent particles of the gas, but we do not adopt the Chapman-Enskog device of simplifying the formulae at each order by using results from previous or

A. D. Erlykin, A. W. Wolfendale

A sudden steepening of the cosmic-ray energy spectrum (the knee) is observed at an energy of about 3 PeV (1 PeV = 10$^{15}$eV). The recent results on extensive air showers allow us to conclude that: a) the knee has an astrophysical origin; b) the &#39;sharpness&#39; and the fine structure of the knee rule out &#39;Galactic Modulation&#39; as the origin of th

Colin Denniston, Mark O. Robbins

We show that molecular dynamics simulations can furnish useful boundary conditions at a solid surface bounding a two-component fluid. In contrast to some previous reports, convective-diffusive flow is consistent with continuum equations down to atomic scales. However, concentration gradients can produce flow without viscous dissipation that is inconsistent w

Pei-Ming Ho, Shun-Pei Miao

In this paper we try to construct noncommutative Yang-Mills theory for generic Poisson manifolds. It turns out that the noncommutative differential calculus defined in an old work is exactly what we need. Using this calculus, we generalize results about the Seiberg-Witten map, the Dirac-Born-Infeld action, the matrix model and the open string quantization fo

A. Ali, E. Lunghi

The recently reported measurements of the CP asymmetry a(psi K) by the BABAR and BELLE collaborations are in good agreement with the standard model (SM) prediction, resulting from the unitarity of the CKM matrix. The so-called minimal flavour violating (MFV) supersymmetric extensions of the standard model, in which the CKM matrix remains the only flavour cha

Jiunn-Wei Chen, Xiangdong Ji

We calculate the leading non-analytic quark-mass dependence in the moments of isovector quark distributions using heavy-baryon chiral perturbation theory. The results differ from those obtained from the Sullivan process in which hard scattering occurs through the virtual pion cloud of the nucleon. Our results provide useful guidance for improving upon the me

Masato Ito

We solve the Einstein equations in higher dimensions with warped geometry where an extra dimension is assumed to have orbifold symmetry $S^{1}/Z_{2}$. The setup considered here is an extension of the five-dimensional Randall-Sundrum model to $5+D$ dimensions, and hidden and observable branes are fixed on the orbifold. It is assumed that the brane tension (se

Bob Coecke

We introduce an explicit definition for &#39;hidden correlations&#39; on individual entities in a compound system: when one individual entity is measured, this induces a well-defined transition of the &#39;proper state&#39; of the other individual entities. We prove that every compound quantum system described in the tensor product of a finite number of Hilb

L. Zhou, H. S. Song, Y. X. Luo

We studied the dispersive dissipation of denegerate-level atom interacting with a single linearly-polarized mode field. It is found that the degeneracy of the atomic level affects the dissipation bahavior of the system as well as the subsystems. The degeneracy of the atomic level augment the periods of entanglement and increase the degree of the maxima stati

Bob Coecke

We recover the rays in the tensor product of Hilbert spaces within a larger class of so called `states of compoundness&#39;, structured as a complete lattice with the `state of separation&#39; as its top element. At the base of the construction lies the assumption that the cause of actuality of a property of one of the (as individual considered) entities in

Fabrice Philippe, Jacques Arnaud

We consider a strictly isolated single-mode optical cavity resonating at angular frequency omega containing atoms whose one-electron level energies are supposed to be: hbar*omega, 2*hbar*omega,...B*hbarω, and m photons. If initially the atoms are in their highest energy state and m=0, we find that at equilibrium: variance(m)/mean(m)=(B+1)/6, indicating that

Azwinndini Muronga

In the context of the Müller-Israel-Stewart second-order theory for dissipative fluids due to Grad, we analyze the effects of thermal conduction and viscosity in heavy ion collisions. We contrast the results to those of the first-order theory due to Eckart and to Landau and Lifshitz and to those of perfect (ideal) fluid due to Euler. We study the energy dens

K. A. Volosov, V. G. Danilov, A. M. Loginov

Exact single-wave and two-wave solutions of systems of equations of Newell-Whitehead type are presented. The Painleve test and calculations in the spirit of Hirota are used to construct these solutions.

V. G. Danilov

We present a new method for constructing solutions to nonlinear evolutionary equations describing the propagation and interaction of nonlinear waves.

J. Bruening, S. Yu. Dobrokhotov, M. Poteryakhin

The problem of averaging for systems with one fast phase was considered from various points of view in many papers. The averaging method of Krylov and Bogolyubov and methods of KAM theory originated this line of research, the most complete results were obtained by Neishtadt, where the coefficients are assumed real analytic. However, in many problems which ar

Luen-Chau Li, Ping Xu

We introduce spin Calogero-Moser systems associated with root systems of simple Lie algebras and give the associated Lax representations (with spectral parameter) and fundamental Poisson bracket relations. The associated integrable models (called integrable spin Calogero-Moser systems in the paper) and their Lax pairs are then obtained via Poisson reduction

Scott Morrison

We define the pull-back of a smooth principal fibre bundle, and show that it has a natural principal fibre bundle structure. Next, we analyse the relationship between pull-backs by homotopy equivalent maps. The main result of this article is to show that for a principal fibre bundle over a paracompact manifold, there is a principal fibre bundle isomorphism b

Jungjai Lee, Yeong Deok Han

In $D$-dimensional gauge theory with a kinetic term based on the p-form tensor gauge field, we introduce a gauge invariant operator associated with the composite formed from a electric $(p-1)$-brane and a magnetic $(q-1)$-brane in $D=p+q+1$ spacetime dimensions. By evaluating the partition function for this operator, we show that the expectation value of thi

El Mostapha Sahraoui, El Hassan Saidi

We study tachyon condensation on noncommutative toric orbifolds with a $Z_2$ discrete group and explore the various kins of brane bound states arising in the case of irrational values of the B-field. We show that $Z_$ symmetry of the orbifolds incorporates naturally anti-branes in the spectrum and leads to equivalent results as those obtained by starting fro

K. Redlich, A. Tounsi

We argue that the main features of baryon and anti-baryon enhancement observed by the WA97 collaboration can be described using canonical formulation of strangeness conservation. Within this formulation strangeness enhancement could be larger at lower collision energies.

Alessia Tricomi

The discovery potential of charged Higgs from pp->tH+- in the H+- -> tau nu decay channel is investigated in CMS and ATLAS. For m_H>m_t, the most relevant channels are H+- -> tb and H+- -> tau nu. Whereas the former has the largest branching ratio it suffers of large irreducible backgrounds, while the latter offers a very clean enviroment when appropriate cu

O. Miyamura, S. Choe

Using the Nambu--Jona-Lasinio (NJL) model we study responses of the pion and kaon masses to changes in the chemical potential, $dm/dμ$, at zero and finite chemical potential. We find that the behavior of $dm/dμ$ for the pion is quite different from that for the kaon. Our results can give a clue for future studies of $dm/dμ$ on the lattice.

Michael Galperin, Abraham Nitzan

Calculations of tunneling matrix elements associated with electron transfer through molecular environments are usually done for given frozen nuclear configurations, assuming that nuclear motions are slow relative to the timescale of a tunneling event. The motivation for this study is a recent calculation [Peskin et al, J. Chem. Phys. 111, 7558 (1999)] that i

Matias Zaldarriaga, Abraham Loeb

Following Loeb (2001), we explore the imprint of the resonant 6708A line opacity of neutral lithium on the temperature and polarization anisotropies of the cosmic microwave background (CMB) at observed wavelengths of 250-350 micron (0.9-1.2 THz). We show that if lithium recombines in the redshift range of z=400-500 as expected, then the standard CMB anisotro

P. Marziani, J. W. Sulentic, T. Zwitter, D. Dultzin-Hacyan

[Latex markup removed] We recently discussed an Eigenvector 1 (E1) parameter space that provides optimal discrimination between the principal classes of broad-line Active Galactic Nuclei (AGN). In this paper we begin a search for the most important physical parameters that are likely to govern correlations and data point distribution in E1 space. We focus on

A. Gazol, E. Vazquez-Semadeni, F. J. Sanchez-Salcedo, J. Scalo

We discuss the temperature distribution in a two-dimensional, thermally unstable numerical simulation of the warm and cold gas in the Galactic disk, including the magnetic field, self-gravity, the Coriolis force, stellar energy injection and a realistic cooling function. We find that ~50% of the turbulent gas mass has temperatures in what would be the therma

Daniel Arndt, Martin J. Savage

We compute the leading non-analytic contributions of the form m_q Log(m_q) to matrix elements of twist-2 operators in the nucleon and pion using effective field theory. Previously omitted one-loop contributions that are related to tree-level matrix elements by chiral symmetry are included.

A. M. Gago, M. M. Guzzo, H. Nunokawa, W. J. C. Teves

We discuss the capabilities of a future neutrino factory based on intense neutrino beams from a muon storage ring to explore the non-standard neutrino matter interactions, which are assumed to be sub-leading effects in the standard mass induced neutrino oscillations. The conjunction of these two mechanisms will magnify fake CP violating effect in the presenc

M. Brisudova, R. P. Woodard, W. H. Kinney

Various theoretical obstacles are associated with a homogeneous and isotropic distribution of ``charge&#39;&#39; which is subject to a repulsive, long-range force. We show how these can be overcome, for all practical purposes, by the simple device of endowing the particle which carries the force with a small mass. The resulting situation may be relevant to a

M. B. Johnson, B. Z. Kopeliovich, I. K. Potashnikova, P. L. McGaughey

We present a new analysis of the E772 and E866 experiments on the nuclear dependence of Drell-Yan (DY) lepton pair production resulting from the bombardment of $^2H$, Be, C, Ca, Fe, and W targets by 800 GeV/c protons at Fermilab. We employ a light-cone formulation of the DY reaction in the rest frame of the nucleus, where the dimuons detected at small values

Roeland P. van der Marel

I construct a near-IR star count map of the LMC and demonstrate, using the viewing angles derived in Paper I, that the LMC is intrinsically elongated. I argue that this is due to the tidal force from the Milky Way. The near-IR data from the 2MASS and DENIS surveys are used to create a star count map of RGB and AGB stars, which is interpreted through ellipse

Roeland P. van der Marel, Maria-Rosa L. Cioni

We present a detailed study of the viewing angles of the LMC disk plane. We find that our viewing direction differs considerably from the commonly accepted values, which has important implications for the structure of the LMC. The discussion is based on an analysis of spatial variations in the apparent magnitude of features in the near-IR color-magnitude dia

M. Diehl, G. Hiller

We propose to study factorization breaking effects in exclusive b decays where they are strongly enhanced over the factorizing contributions. This can be done by selecting final-state mesons with a small decay constant or with spin greater than one. We find a variety of decay modes which could help understand the dynamical origin of factorization and the mec

Justin R. David

We study ghost number one excitations on the sliver to investigate the solution of string field actions around the tachyon vacuum. The generalized gluing and resmoothing theorem is used to develop a method for evaluating the effective action for excitations on both the wedge states and the sliver state. We analyze the discrete symmetries of the resulting eff

M. F. Corcoran, J. H. Swank, R. Petre, K. Ishibashi

Eta Car may be the most massive and luminous star in the Galaxy and is suspected to be a massive, colliding wind binary system. The CHANDRA X-ray observatory has obtained a calibrated, high-resolution X-ray spectrum of the star uncontaminated by the nearby extended soft X-ray emisssion. Our 89 ksec CHANDRA observation with the High Energy Transmission Gratin

B. Altschul, R. Jackiw

A recent proposal that gravity theory is an emergent phenomenon also entails the possibility of photon decay near the Schwarzschild event horizon. We present a possible mechanism for such decay, which utilizes a dimensional reduction near the horizon.

Frank Verstraete, Jeroen Dehaene, Bart De Moor

A general mathematical framework is presented to describe local equivalence classes of multipartite quantum states under the action of local unitary and local filtering operations. This yields multipartite generalizations of the singular value decomposition. The analysis naturally leads to the introduction of entanglement measures quantifying the multipartit

A. Feinstein, K. E. Kunze, M. A. Vazquez-Mozo

We construct a broad family of exact solutions to the five-dimensional Einstein equations coupled to a scalar field with an exponential potential. Embedding a three-brane in these bulk space-times in a particular way we obtain a class of self-tuned curved brane worlds in which the vacuum energy on the brane is gravitationally idle, the four-dimensional geome