June 1998 arXiv papers — page 7

Jean-François Delmas, Jean-Stéphane Dhersin

\def\R{\mathbb R} We give a characterization of G-regularity for super-Brownian motion and the Brownian snake. More precisely, we define a capacity on $E=(0,\infty)\times \R^d$, which is not invariant by translation. We then prove that the hitting probability of a Borel set $A\subset E$ for the graph of the Brownian snake starting at $(0,0)$ is comparable, u

Jean-François Delmas

We consider a super-Brownian motion $X$. Its canonical measures can be studied through the path-valued process called the Brownian snake. We obtain the limiting behavior of the volume of the $ε$-neighborhood for the range of the Brownian snake, and as a consequence we derive the analogous result for the range of super-Brownian motion and for the support of t

Siye Wu

Consider a holomorphic torus action on vector bundles over a complex manifold which lifts to a holomorphic vector bundle. When the connected components of the fixed-point set are partially ordered, we construct, using sheaf-theoretical techniques, two spectral sequences that converges to the twisted Dolbeault cohomology groups and those with compact support,

Liang-gang Liu, Xiang-Qian Luo, Wei Chen

We propose a new method to calculate the 4-dimensional divergent integrals. By calculating the one loop integral as an example, the regularization of the integrals in 3-dimension momentum space are given in details. We find that the new method gives the same results as the traditional dimensional regularization method gives, but the new method has the advant

Joao Branco

We probe a non-supersymmetric D6 + D0 state with D6-branes and find agreement at subleading order between the supergravity and super Yang-Mills description of the long-distance, low-velocity interaction.

B. B. Deo

We prove that the bosons and massless fermions of one generation of the standard model are supersymmetric partners of each other. Except for one additional auxilliary vector boson, there are no other SUSY particles.

Youngjai Kiem, Chang-Yeong Lee, Dahl Park

We study the doubly charged Callan-Giddings-Harvey-Strominger (CGHS) model, which has black hole solutions that were found to be U-dual to the D1-D5-KK black holes of the IIB supergravity. We derive the action of the model via a spontaneous compactification on S^3 of the IIB supergravity on S^1*T^4 and obtain the general static solutions including black hole

Ali H. Chamseddine

It is shown that N=4 gauged supergravity in four dimensions is obtained by compactifying N=1 supergravity in ten dimensions on the group manifold $S^3\times S^3$. This could be further related to supergravity in eleven dimensions. Analysis of supersymmetry conditions of N=4 gauged supergravity in four dimensions reveals solutions which preserve 1/4 of the su

Indranil Dasgupta, L. C. R. Wijewardhana

In 2+1 dimensional gauge thories with $SU(N_c)$ color and $2N_f$ flavors of quarks in the fundamental representation, sphalerons, if present may lead to quark condensation and chiral symmetry breaking. The effect is similar to instanton induced chiral symmetry breaking in 3+1 dimensions and is due to the interaction of quark propagators with sphalerons. The

Stanley J. Brodsky

Commensurate scale relations are perturbative QCD predictions which relate observable to observable at fixed relative scales, independent of the choice of intermediate renormalization scheme or other theoretical conventions. A prominent example is the "generalized Crewther relation" which connects the Bjorken and Gross-Llewellyn Smith deep inelastic

L. Clavelli, L. R. Surguladze

We deduce the gluino contribution to the three-loop QCD quark mass anomalous dimension function within the minimal supersymmetric Standard Model (MSSM) from its standard QCD expression. This work is a continuation of the program of computation of MSSM renormalization group functions.

E. M. Lipmanov

In a model with four neutrino mass eigenstates grouping in two narrow doublets the condition of maximal mixing of the doublet neutrino components leads to a simple four-neutrino mixing matrix which is related to two connected effective two-neutrino mixing patterns. As a result, large values of the neutrino oscillation amplitudes for both the solar and atmosp

Daniela Kirilova, Mihail Chizhov

In this work we present the results of our numerical analysis of the effect of lepton asymmetries L on neutrino oscillations and consequently on helium production in a model of cosmological nucleosynthesis with active-sterile neutrino oscillations. We performed detail calculations of the neutron-proton ratio till its freezing and the subsequent synthesis of

F. Ferrer, J. A. Grifols, M. Nowakowski

We revisit and extend previous work on neutrino mediated long range forces in a backround at finite temperature. For Dirac neutrinos, we correct existing results. We also give new results concerning spin-dependent as well as spin-independent long range forces associated to Majorana neutrinos. An interesting outcome of the investigation is that, for both type

B. Pötter

JetViP is a computer program for the calculation of inclusive single- and dijet cross sections in eP- and e-gamma-scattering in NLO QCD. The virtuality of the photon, radiated by the incoming electron, can be chosen in a continuous range, reaching from photoproduction into deep inelastic scattering. The various contributions to the full jet cross section, in

H. Neufeld, J. Gasser, G. Ecker

We employ notions familiar from supersymmetry for constructing the one-loop functional of general quantum field theories with bosons and fermions (spin < 1). To demonstrate the advantages of such an approach for calculating one-loop divergences, we analyse a simple Yukawa theory with two different versions of a super-heat-kernel expansion. These methods also

A. Bialas, K. Zalewski

The influence of the HBT effect on the momentum spectra of independently produced pions is studied using the method developed earlier for discussion of multiplicity distributions. It is shown that in this case all the spectra and multiparticle correlation functions are expressible in terms of one function of two momenta. It is also shown that at the critical

E. Levin

This talk is given at &#34;Continious Advances in QCD&#34;, Minnesota, April 16-19,1998. It is a brief report on our results in high parton density QCD. The main goal of this talk is to discuss the new evolution equation which was obtained and solved by A.Ayala, M. Ducati and E.Levin and by E. Gotsman, E. Levin and U. Maor, and to share with you the physics

Jes Madsen

Supersymmetric Q-balls trapped in neutron stars or white dwarfs may cause the stars to explode. Trapping of Q-balls in neutron stars is shown to be less likely, but trapping in neutron star progenitors more likely than hitherto assumed, making neutron stars very sensitive Q-ball &#34;detectors&#34;. White dwarfs only trap potentially dangerous Q-balls in a n

Thorsten Ohl

We present a new adaptive Monte Carlo integration algorithm for ill-behaved integrands with non-factorizable singularities. The algorithm combines Vegas with multi channel sampling and performs significantly better than Vegas for a large class of integrals appearing in physics.

M. Praszalowicz, T. Watabe, K. Goeke

We reconsider canonical quantization of the rotating soliton in the SU(3) Chiral Quark-Soliton Model. We show that at the level of 1/N_c, in contrast to the SU(2) version of the model, there appear terms which spoil the commutation rules of the flavor generators. Terms of similar origin are also present in the expressions for axial couplings and magnetic mom

Simon Hands

I review the properties of the three-dimensional Gross-Neveu model formulated with non-zero chemical potential and temperature, focussing on results obtained by lattice Monte Carlo simulation.

Isabel Campos

The properties of several phase transitions relevant to the lattice study of Quantum Field Theory are investigated.

B. M. Barbashov, A. B. Pestov

A spinor current-source is found in the Weyl non-Abelian gauge theory which does not contain the abstract gauge space. It is shown that the searched spinor representation can be constructed in the space of external differential forms and it is a 16-component quantity for which a gauge-invariant Lagrangian is determined. The connexion between the Weyl non-Abe

G. Rau, P. C. Klipstein, N. F. Johnson

In this theoretical investigation we predict an unusual interaction between a discrete state and a continuum of states, which is closely related to the case of Fano-interference. It occurs in a GaAs/AlxGa1-xAs quantum well between the lowest light-hole exciton and the continuum of the second heavy-hole exciton. Unlike the typical case for Fano-resonance, the

H. Tolga Ilhan, Philip F. Bagwell

Control of the Josephson current by varying a gate current has recently been demonstrated in both 4-terminal and 3-terminal junctions. We show that, when the the gates are weakly coupled to the Josephson junction, the Josephson current versus gate current (or versus gate voltage) relation is the same for both the 4- and 3- terminal geometries. At low tempera

G. G. Kozlov

The problem of the one-exciton absorption spectrum is considered for the lattice of two-level interacting atoms whose initial energy splitting depends on the coordinate. It is shown that for some types of interatomic interaction, this problem can be reduced to a differential equation of Schrodinger type, which, in some cases, can be solved in closed form. By

M. Watzlawek, H. Loewen, C. N. Likos

The core-core structure factor of dense star polymer solutions in a good solvent is shown theoretically to exhibit an unusual behaviour above the overlap concentration. Unlike usual liquids, these solutions display a structure factor whose first peak decreases by increasing density while the second peak grows. The scenario repeats itself with the subsequent

Andrea De Martino, Andrea Giansanti

We present a stochastic evolutionary model obtained through a perturbation of Kauffman&#39;s maximally rugged model, which is recovered as a special case. Our main results are: (i) existence of a percolation-like phase transition in the finite phase space case; (ii) existence of non self-averaging effects in the thermodynamic limit. Lack of self-averaging em

R. Neudert, M. Knupfer, M. S. Golden, J. Fink

We have determined the dynamical dielectric response of a one-dimensional, correlated insulator by carrying out electron energy-loss spectroscopy on Sr2CuO3 single crystals. The observed momentum and energy dependence of the low-energy features, which correspond to collective transitions across the gap, are well described by an extended one-band Hubbard mode

A. Gonzalez, B. Partoens, A. Matulis, F. M. Peeters

The Pade approximant technique and the variational Monte Carlo method are applied to determine the ground-state energy of a finite number of charged bosons in two dimensions confined by a parabolic trap. The particles interact repulsively through a Coulombic, 1/r, potential. Analytic expressions for the ground-state energy are obtained. The convergence of th

Mark Leadbeater, Rudolf A. Roemer, Michael Schreiber

We present calculations of the localisation length, $λ_{2}$, for two interacting particles (TIP) in a one-dimensional random potential, presenting its dependence on disorder, interaction strength $U$ and system size. $λ_{2}(U)$ is computed by a decimation method from the decay of the Green function along the diagonal of finite samples. Infinite sample size e

S. Hikami, R. Pnini

The density of state for a complex $N\times N$ random matrix coupled to an external deterministic source is considered for a finite N, and a compact expression in an integral representation is obtained.

Yorick Wilks, Mark Stevenson

Word sense disambiguation algorithms, with few exceptions, have made use of only one lexical knowledge source. We describe a system which performs unrestricted word sense disambiguation (on all content words in free text) by combining different knowledge sources: semantic preferences, dictionary definitions and subject/domain codes along with part-of-speech

James S. Bullock, Joel R. Primack

We review the basic arguments for the likelihood of non-Gaussian density perturbations in inflation models with primordial black hole (PBH) production. We discuss our derived distributions of field fluctuations and their implications, specifically commenting on the fine-tuning problem. We also discuss how the derived distributions may be affected when linked

Luca Zampieri, Stuart L. Shapiro, Monica Colpi

Observations combined with theoretical modeling of the light curve of the recently discovered supernova 1997D in NGC 1536 suggest that it might host a black hole formed in the aftermath of the explosion. We consider some observable consequences of a black hole in SN 1997D and estimate the late--time accretion luminosity of the material which falls back onto

S. E. Woosley, Ronald G. Eastman, Brian P. Schmidt

Recently a Type Ic supernova, SN 1998bw, was discovered coincident with a gamma-ray burst, GRB 980425. The supernova had unusual radio, optical, and spectroscopic properties. We explore here models based upon helium stars in the range 9 - 14 Msun and carbon-oxygen stars 6 - 11 Msun which experience unusually energetic explosions (kinetic energy 0.5 - 2.8 x 1

John M. Carpenter, D. B. Sanders

We present 45&#34;-47&#34; angular resolution maps at 50&#34; sampling of the 12CO and 13CO J=1-0 emission toward a 1.39 deg x 1.33 deg region in the W51 HII region complex. These data permit the spatial and kinematic separation of several spectral features observed along the line of sight to W51, and establish the presence of a massive (1.2 x 10^6 Mo), larg

David Hughes, Steve Serjeant, James Dunlop, Michael Rowan-Robinson

The advent of sensitive sub-mm array cameras now allows a proper census of dust-enshrouded massive star-formation in very distant galaxies, previously hidden activity to which even the faintest optical images are insensitive. We present the deepest sub-mm survey of the sky to date, taken with the SCUBA camera on the James Clerk Maxwell Telescope and centred

E. R. Seaquist, D. T. Frayer, M. B. Bell

We report observations and an analysis of the distribution of HCO+(1-0) and HCO+(4-3) emission in the central 1 kpc star forming region of M82. Comparisons are made with other star formation indicators such as the mm continuum, the distribution of radio SNR&#39;s and the molecules CO and OH. In a broad sense, the HCO+ is distributed in a way similar to the C

S. Bardelli, A. Pisani, M. Ramella, E. Zucca

The &#34;algorithm driven by the density estimate for the identification of clusters&#34; (DEDICA, Pisani 1993, 1996) is applied to the A3558 cluster complex in order to find substructures. This complex, located at the center of the Shapley Concentration supercluster, is a chain formed by the ACO clusters A3556, A3558 and A3562 and the two poor clusters SC 1

Stephen Holland, Bjarne Thomsen

We present simulated J- and K-band observations of stars in the Virgo and Coma clusters of galaxies using the proposed Next Generation Space Telescope with a Near-Infrared Camera, and discuss some of the science results that might be obtained. The proposed telescope will be able to resolve the brightest ~3 magnitudes of the red giant branch in the halos of g

A. Blaauw, R. Ramachandran

We explore a simple model for the representation of the observed distributions of the motions, and the characteristic ages of the local population of pulsars. The principal difference from earlier models is the introduction of a unique value, S, for the kick velocity with which pulsars are born. We consider separately the proper motion components in galactic

A. A. Deshpande, R. Ramachandran

We present here a method to study the distribution of electron density fluctuations in pulsar directions as well as to estimate pulsar distances. The method, based on a simple two-component model of the scattering medium discussed by Gwinn et al. (1993), uses scintillation & proper motion data in addition to the measurements of angular broadening & temporal

Alfred Gautschy, Hideyuki Saio, Housi Harzenmoser

Rapidly oscillating Ap stars consitute a unique class of pulsators to study nonradial oscillations under some - even for stars - unusual physical conditions. These stars are chemically peculiar, they have strong magnetic fields, and they often pulsate in several high-order acoustic modes simultaneously. We discuss here an excitation mechanism for short-perio

A. Lecavelier des Etangs

The dust disk around Beta Pictoris must be produced by collision or by evaporation of orbiting Kuiper belt-like objects. Here we extend the already proposed Orbiting-Evaporating-Bodies (OEB) scenario in which the disk is a gigantic multi-cometary tail supplied by slowly evaporating bodies like Chiron. We show that the number of these OEBs must be several ten

Takashi Murayama, Yoshiaki Taniguchi

Having found that type 1 Seyfert nuclei have excess [FeVII]6087 emission with respect to type 2s, Murayama & Taniguchi have proposed that the high-ionization nuclear emission-line region (HINER) traced by the [FeVII]6087 emission resides in the inner wall of dusty tori. The covering factor of the torus is usually large (e.g., ~ 0.9). Further, electron densit

Michael Rauch

Observations of redshifted Lyman alpha forest absorption in the spectra of quasistellar objects (QSOs) provide a highly sensitive probe of the distribution of gaseous matter in the universe. Over the past two decades optical spectroscopy with large ground-based telescopes, and more recently ultraviolet spectroscopy from space have yielded a wealth of informa

Sergei Gukov

We discuss twisted states of AdS orbifolds which couple to N=2 chiral primary operators not invariant under exchange of the gauge factors. Kaluza-Klein reduction on the fixed circle gives the correct conformal dimensions of operators in the superconformal theory and involves some aspects of monopole dynamics in the non-trivial background. As a byproduct we f

Alessandro Vespignani, Ronald Dickman, Miguel A. Munoz, Stefano Zapperi

We use a phenomenological field theory, reflecting the symmetries and conservation laws of sandpiles, to compare the driven dissipative sandpile, widely studied in the context of self-organized criticality, with the corresponding fixed-energy model. The latter displays an absorbing-state phase transition with upper critical dimension $d_c=4$. We show that th

P. Kanti, J. Rizos, K. Tamvakis

We study a general field theory of a scalar field coupled to gravity through a quadratic Gauss-Bonnet term $ξ(ϕ) R^2_{GB}$. The coupling function has the form $ξ(ϕ)=ϕ^n$, where $n$ is a positive integer. In the absence of the Gauss-Bonnet term, the cosmological solutions for an empty universe and a universe dominated by the energy-momentum tensor of a scalar

R. P. Norris, S. E. Byleveld, P. J. Diamond, S. P. Ellingsen

We show that in many methanol maser sources the masers are located in lines, with a velocity gradient along them which suggests that the masers are situated in edge-on circumstellar, or protoplanetary, disks. We present VLBI observations of the methanol maser source G309.92+0.48, in the 12.2 GHz transition, which confirm previous observations that the masers

T. Fulop, S. D. Katz

The wave function of quantum mechanics is not a boost invariant and gauge invariant quantity. Correspondingly, reference frame dependence and gauge dependence are inherited to most of the elements of the usual formulation of quantum mechanics (including operators, states and events). If a frame dependent and gauge dependent formalism is called, in short, a r

H. Garcia-Compean, A. M. Uranga

We study type IIA configurations of D4 branes and three kinds of NS fivebranes. The D4 brane world-volume has finite extent in three directions, giving rise to a two-dimensional low-energy field theory. The models have generically $(0,2)$ supersymmetry. We determine the rules to read off the spectrum and interactions of the field theory from the brane box co

Henry P. Stapp

A recent proof, formulated in the symbolic language of modal logic, shows that a well-defined formulation of the possibility mentioned in the title is answered affirmatively. In the paper being commented upon several proposals were made about how to translate this symbolic proof into prose, and it was concluded, on the basis of those proposed translations, t

Konrad Banaszek, Krzysztof Wodkiewicz

We demonstrate that the Wigner function of the Einstein-Podolsky-Rosen state, though positive definite, provides a direct evidence of the nonlocal character of this state. The proof is based on an observation that the Wigner function describes correlations in the joint measurement of the phase space displaced parity operator.

Konrad Banaszek, Krzysztof Wodkiewicz

We propose an experiment demonstrating the nonlocality of a quantum singlet-like state generated from a single photon incident on a beam splitter. Each of the two spatially separated apparatuses in the setup performs a strongly unbalanced homodyning, employing a single photon counting detector. We show that the correlation functions violating the Bell inequa

Laura E. Jones, Donald V. Helmberger

Based on waveform data from a profile of aftershocks following the north-south trace of the June 28, 1992 Landers rupture across the Mojave desert, we construct a new velocity model for the Mojave region which features a thin, slow crust. Using this model, we obtain source parameters, including depth and duration, for each of the aftershocks in the profile,

M. A. Pichowsky

A Dyson-Schwinger-based model of pomeron exchange is employed to calculate diffractive rho-, phi- and J/psi-meson electroproduction cross sections. It is shown that the magnitude of the current-quark mass m_f of the quark and antiquark inside the produced vector meson determines the onset of the asymptotic-q^2 power-law behavior of the cross section, and how

Mirroslav Tz. Yotov

The interpretation, due to T. Mabuchi, of the classical Futaki invariant of Fano toric manifolds is extended to the case of the Generalized Futaki invariant, introduced by W. Ding and G. Tian, of almost Fano toric varieties. As an application it is shown that the real part of the Generalized Futaki invariant is positive for all degenerations of the Fano mani

Morten Weis

This thesis discusses the topological aspects of quantum gravity, focusing on the connection between 2D quantum gravity and 2D topological gravity. The mathematical background for the discussion is presented in the first two chapters. The possible gauge formulations of 2D topological gravity as a BF or a Super BF theory are presented and compared against 2D

S. P. de Alwis

We review the assumptions and the logic underlying the derivation of DLCQ Matrix models. In particular we try to clarify what remains valid at finite $N$, the role of the non-renormalization theorems and higher order terms in the supergravity expansion. The relation to Maldacena&#39;s conjecture is also discussed. In particular the compactification of the Ma

D. Elazzar Kaplan, Francois Lepeintre, Antonio Masiero, Ann E. Nelson

We present a supersymmetric model of flavor. A single U(1) gauge group is responsible for both generating the flavor spectrum and communicating supersymmetry breaking to the visible sector. The problem of Flavor Changing Neutral Currents is overcome, in part using an `Effective Supersymmetry&#39; spectrum among the squarks, with the first two generations ver

B. G. Sidharth

A recent cosmological model is recapitulated which deduces the correct mass, radius and age of the universe as also the Hubble constant and other well known apparently coincidental relations. It also predicts an ever expanding accelerating universe as is confirmed by latest supernovae observations. Finally the Big Bang model is recovered as a suitable limiti

Daniel C. Hong

Starting from Enskog equation of hard spheres of mass m and diameter D under the gravity g, we first derive the exact equation of motion for the equilibrium density profile at a temperature T and examine its solutions via the gradient expansion. The solutions exist only when βμ\le μ_o \approx 21.756 in 2 dimensions and μ_o\approx 15.299 in 3 dimensions, wher

C. A. Ullrich, G. Vignale

We use time-dependent (current) density functional theory to study collective transitions between the two lowest subbands in GaAs/AlGaAs quantum wells. We focus on two systems where experimental results are available: a wide single and a narrow asymmetric double well. The aim is to calculate frequency and linewidth of collective electronic modes damped via e

G. Sierra, M. A. Martin-Delgado, S. R. White, D. J. Scalapino

We introduce a class of models defined on ladders with a diagonal structure generated by $n_p$ plaquettes. The case $n_p=1$ corresponds to the necklace ladder and has remarkable properties which are studied using DMRG and recurrent variational ansatzes. The AF Heisenberg model on this ladder is equivalent to the alternating spin-1/spin-1/2 AFH chain which is

V. I. Yukalov, E. P. Yukalova, F. A. Oliveira

The self--similar renormalization group is used to obtain expressions for the spectrum of the Hamiltonian with the Yukawa potential. The critical screening parameter above which there are no bound states is also obtained by this method. The approach presented illustrates that one can achieve good accuracy without involving extensive numerical calculations, b

John Carroll, Guido Minnen, Ted Briscoe

Research into the automatic acquisition of lexical information from corpora is starting to produce large-scale computational lexicons containing data on the relative frequencies of subcategorisation alternatives for individual verbal predicates. However, the empirical question of whether this type of frequency information can in practice improve the accuracy

Phil Arras, Dong Lai

In magnetized proto-neutron stars, neutrino cross sections depend asymmetrically on the neutrino momenta due to parity violation. However, these asymmetric opacities do not induce any asymmetric flux in the bulk interior of the star where neutrinos are nearly in thermal equilibrium. Consequently, parity violation in neutrino absorption and scattering can onl

Dong Lai, Y. -Z. Qian

The original paper describes neutrino cooling calculations in the presence of asymmetric neutrino opacities due to parity violation in strong magnetic fields. In early April, through the work of P. Arras and D. Lai at Cornell (see astro-ph/9806285) we became aware that the paper contains a serious flaw: although the neutrino scattering opacities depend asymm

Guenter Sigl, Martin Lemoine, Peter Biermann

We present detailed numerical simulations and analytical approximations of the propagation of nucleons above 10**(19) eV in the Local Supercluster, assuming that the ambient magnetic field is turbulent, and its strength 0.01 < B_rms < 1 micro-Gauss. In such strong magnetic fields, protons in the low energy part of the spectrum, 10**(19) eV < E < E_C diffuse,

Masahiko Hayashi

The dissipation process in two dimensional BCS superconductor due to the quasiparticles in the core of moving vortex is studied from a quantum mechanical point of view, especially paying attention to the spectral flow of the bound state energies in the vortex core. In order to clarify the nature of the spectral flow, we performed a numerical study of a finit

L. Pasquali, M. H. Reno, I. Sarcevic

We reexamine the charm contribution to atmospheric lepton fluxes in the context of perturbative QCD. We include next-to-leading order corrections and discuss theoretical uncertainties due to the extrapolations of the gluon distributions at small-x. We show that the charm contribution to the atmospheric muon flux becomes dominant over the conventional contrib

Ph. Brax, T. Wynter

We study curved space versions of matrix string theory taking as a definition of the theory a gauged matrix sigma model. By analyzing the divergent terms in the loop expansion for the effective action we reduce the problem to a simple matrix generalization of the standard string theory beta function calculation. It is then demonstrated that the model can onl

Friedrich Wagemann

The Dolbeault resolution of the sheaf of holomorphic vector fields $Lie$ on a complex manifold $M$ relates $Lie$ to a sheaf of differential graded Lie algebras, known as the Frölicher-Nijenhuis algebra $g$. We establish - following B. L. Feigin - an isomorphism between the differential graded cohomology of the space of global sections of $g$ and the hypercoh

Renyue Cen, Jeremiah P. Ostriker

New, high resolution, large-scale, cosmological hydrodynamic galaxy formation simulations of a standard cold dark matter model (with a cosmological constant) are utilized to predict the distribution of baryons at the present and at moderate redshift. It is found that the average temperature of baryons is an increasing function of time, with most of the baryo

Thomas Wynter

We study the loop expansion for the low energy effective action for matrix string theory. For long string configurations we find the result depends on the ordering of limits. Taking $g_s\to 0$ before $N\to\infty$ we find free strings. Reversing the order of limits however we find anomalous contributions coming from the large $N$ limit that invalidate the loo

W. A. Hofer

The theoretical foundations of quantum mechanics and de Broglie--Bohm mechanics are analyzed and it is shown that both theories employ a formal approach to microphysics. By using a realistic approach it can be established that the internal structures of extended particles comply with a wave-equation. Including external potentials yields the Schrodinger equat

W. A. Hofer

Based on the concept of extended particles recently introduced we perform a Gedankenexperiment accelerating single electrons with photons of suitably low frequency. Accounting for relativistic time dilation due to the acquired velocity and in infinite repetition of single absorption processes it can be shown that the kinetic energy in the infinite limit is e

T. Schaefer

We argue that cold quark matter is a color superconductor. The Cooper pairs of QCD are spin-isospin zero, color anti-triplet diquarks. In this contribution we review some of the available information on the quark-quark interaction in QCD. We show that instantons provide a strongly attractive interaction in the scalar diquark channel. In the high density phas

J. Zhang, N. Mobed, M. Benmerrouche

We study the reaction $π^\pm p \to π^\pm π^+ n$ and $π^- p \to π^0 π^0 n$ in heavy-baryon chiral perturbation theory of chiral order three from threshold up to pion laboratory kinetic energies of 400 MeV. We find that the contributions from amplitudes of chiral order three are large and play an essential role in reproducing the experimental data.

Yuli B. Rudyak

In [R2] and [RO] the Arnold conjecture for closed symplectic manifolds with trivial second homotopy group was proved. This proof used surgery and cobordism theory. Here we give a purely cohomological proof of this result.

Thomas Kerler

We develop a calculus of surgery data, called bridged links, which involves besides links also pairs of balls that describe one-handle attachements. As opposed to the usual link calculi of Kirby and others this description uses only elementary, local moves(namely modifications and isolated cancellations), and it is valid also on non-simply connected and disc

Thomas Kerler

We recall an extension of Kirby&#39;s Calculus on non-simply connected 3-manifolds given in [FR], and the surgery calculus of bridged links from [Ke], which involves only local moves. We give a short combinatorial proof that the two calculi are equivalent, and thus describe the same classes of 3-manifolds. This makes the proofs for the validity of surgery ca

Dmitri Sorokin

Coupling of a membrane and a five-brane to the bosonic sector of D=11 supergravity is considered. The five--brane is a dyonic object which carries both an electric and a magnetic charge of the D=11 three-form gauge field $A^3$, and it couples not only to $A^3$ but also minimally couples to a six-form field $A^6$ dual to $A^3$. This implies that the 5-brane s

Mu-in Park

It is shown that (2+1)-dimensional QED reveals several unusual effects due to the surface-term contributions. It is also shown that this system provides a new pairing mechanism for the high-$T_c$ superconductivity on the plane.

Sarira Sahu, Vishnu M. Bannur

The active-sterile neutrino conversion is studied for neutrino propagating in the axial potential generated by magnetised electron plasma in the supernova medium. We consider the effect of random magnetic field $B_{rms}$ on the average neutrino conversion probability. We obtained the constraint on $\Delta m^2$ and $\sin^2 2\theta$ for different strength of t

Vladimir S. Mashkevich

We argue that the conventional quantum field theory in curved spacetime has a grave drawback: The canonical commutation relations for quantum fields and conjugate momenta do not hold. Thus the conventional theory should be denounced and the related results revised. A Hamiltonian version of the canonical formalism for a free scalar quantum field is advanced,

J. Ferrer, M. A. Gonzalez-Alvarez, J. Sanchez-Cañizares

Superflow in a phenomenological tight-binding model for the superconducting state of some High-temperature superconductors is discussed thoroughly. The formalism used is explicitly gauge-invariant and currents are computed exactly within BCS theory, going therefore beyond linear response theory. The dependence of gap functions, current density, critical curr

Robert V. Gentry

A nonhomogeneous universe with vacuum energy, but without spacetime expansion, is utilized together with gravitational and Doppler redshifts as the basis for proposing a new interpretation of the Hubble relation and the 2.7K Cosmic Blackbody Radiation.

H. Xu, K. Makishima, Y. Fukazawa, Y. Ikebe

Using the X-ray data from \ASCA, spectral and spatial properties of the intra-cluster medium (ICM) of the cD cluster Abell 1795 are studied, up to a radial distance of $\sim 12&#39;$ ($\sim 1.3$ $h_{50}^{-1}$ kpc). The ICM temperature and abundance are spatially rather constant, although the cool emission component is reconfirmed in the central region. The a

David L. Meier

A new field of numerical astrophysics is introduced which addresses the solution of large, multidimensional structural or slowly-evolving problems (rotating stars, interacting binaries, thick advective accretion disks, four dimensional spacetimes, etc.). The technique employed is the Finite Element Method (FEM), commonly used to solve engineering structural

Julian Lee, Sang-Jin Sin

We generalize the M-theoretic duality of Schmaltz and Sundrum to the product group SU(N) x SU(N&#39;) case. We show that the type IIA brane configurations for dual gauge theories are in fact two special limits of the same M-theory 5-brane, just as in the case of the simple SU(N) group.

Jean-Pascal Rueff, Chi-Chang Kao, Viktor V. Struzhkin, James Badro

We report the observation of the pressure-induced high-spin to low-spin transition in FeS using new high-pressure synchrotron x-ray emission spectroscopy techniques. The transition is evidenced by the disappearance of the low-energy satellite in the Fe K$β$ emission spectrum of FeS. Moreover, the phase transition is reversible and closely related to the stru

V. F. Gantmakher, M. V. Golubkov, V. T. Dolgopolov, G. E. Tsydynzhapov

We have studied the magnetic-field-tuned superconductivity destroying quantum transition in amorphous In-O films with the onset of superconductivity in zero field at about 2 K. At temperatures down to 30 mK the critical resistance R_c=R(T,B_c) has been found to change approximately linearly with temperature, which is in contradiction to a standard descriptio

Dirk Helbing, Benno Tilch

Floating car data of car-following behavior in cities were compared to existing microsimulation models, after their parameters had been calibrated to the experimental data. With these parameter values, additional simulations have been carried out, e.g. of a moving car which approaches a stopped car. It turned out that, in order to manage such kinds of situat

John March-Russell

The magnitude of the Fayet-Iliopoulos term is calculated for compactifications of Type-I string theory and Horava-Witten M-theory in which there exists a pseudo-anomalous U(1)_X. Contrary to various conjectures, it is found that in leading order in the perturbative expansion around the weakly-coupled M-theory or Type-I limits, a result identical to that of t

Eduardo Eyras, Bert Janssen, Yolanda Lozano

We construct the explicit worldvolume effective actions of the type IIB NS-5-brane and KK-monopole. These objects are obtained through a T-duality transformation from the IIA KK-monopole and the IIA NS-5-brane respectively. We show that the worldvolume field content of these actions is precisely that necessary to describe their worldvolume solitons. The IIB

S. Gardner

An isospin analysis of $B\toππ$ decays yields $\sin 2α$, where $α$ is the usual CKM angle $α\equiv arg [-V_{td}V_{tb}^\ast /(V_{ud}V_{ub}^\ast)]$, without hadronic uncertainty if isospin is a perfect symmetry. Isospin, however, is broken not only by electroweak effects but also by the u and d quark mass difference. The latter generates $π^0-η, η&#39;$ mixing