October 2002 arXiv papers — page 7

Y. Aoki, T. Namiki, T. Kanayama, S. Ohsaki

Rare 4f^2-based heavy-fermion behaviors have been revealed recently in Pr-based filled skutterudites PrFe4P12 and PrOs4Sb12. Recent studies on the thermal properties on both compounds are reported, putting emphasis on the field-induced ordered phase found in PrOs4Sb12.

H. Salamati P. Kameli F. S. Razavi

The effect of Pr substitution on the superconductivity and interlayer coupling of Bi2212 system is investigated. Magnetic and transport measurements were performed for purposes of characterization. The superconducting transition temperature Tc first increased and then decreased till it became zero at x=0.6. The effective superconducting volume also decreases

T. Raz, D. Ritter, G. Bahir, D. Gershoni

InAs self-assembled quantum dots were grown on strained layers of GaxIn1-xP (0 < x < 0.3) on InP substrates. We show that the quantum dots have narrow vertical dimensions, ranging between 2 to 10 monolayers only. The dot layer photoluminescence spectrum is composed of distinct spectral peaks, resulting from the discrete distribution of the dot heights. The d

J. D. Dull, H. N. Cohn, P. M. Lugger, B. W. Murphy

It has recently come to our attention that there are axis scale errors in three of the figures of Dull et al. (1997, hereafter D97). D97 presented Fokker-Planck models for the collapsed-core globular cluster M15 that include a dense, centrally concentrated population of neutron stars and massive white dwarfs, but do not include a central black hole. In this

Keith M. Ashman

The discovery of young globular clusters in merging galaxies and other environments provides an opportunity to study directly the process of globular cluster formation. Empirically it appears that globular cluster formation occurs preferentially in regions in which star formation occurs at a high rate and efficiency. Further, the interstellar medium in such

Noam Soker, Amos Harpaz

Late asymptotic giant branch (AGB) and early post-AGB stars which are progenitors of planetary nebulae lose mass at extremely high rate, in what is termed a superwind. We show that the existence of this superwind during the post-AGB phase cannot be explained with models where the stellar effective temperature is the sole main physical parameter which determi

Andrew R. Frey, Anupam Mazumdar

We study the potential induced by imaginary self-dual 3-forms in compactifications of string theory and the cosmological evolution associated with it. The potential contains exponentials of the volume moduli of the compactification, and we demonstrate that the exponential form of the potential leads to a power law for the scale factor of the universe. This p

David Joyner, Will Traves

We study the action of a finite group on the Riemann-Roch space of certain divisors on a curve. If $G$ is a finite subgroup of the automorphism group of a projective curve $X$ over an algebraically closed field and $D$ is a divisor on $X$ left stable by $G$ then we show the irreducible constituents of the natural representation of $G$ on the Riemann-Roch spa

Valeria Ferrari, Giovanni Miniutti, Jose&#39; A. Pons

We study the gravitational radiation associated to the non--radial oscillations of newly born, hot neutron stars. The frequencies and damping times of the relevant quasi--normal modes are computed for two different models of proto--neutron stars, at different times of evolution, from its birth until it settles down as a cold neutron star. We find that the os

Sergei Yu. Alexandrov, Vladimir A. Kazakov

We calculate the free energy, energy and entropy in the matrix quantum mechanical formulation of 2D string theory in a background strongly perturbed by tachyons with the imaginary Minkowskian momentum $\pm i/R$ (``Sine-Liouville&#39;&#39; theory). The system shows a thermodynamical behaviour corresponding to the temperature $T=1/(2πR)$. We show that the micr

Li Gang Jin, Chong Sheng Li, Jian Jun Liu

We present the calculations of the complete next-to-leading order (NLO) inclusive total cross sections for the associated production processes $pp\to \tilde{t}_i\tildeχ_k^-+X$ in the Minimal Supersymmetric Standard Model at the CERN Large Hadron Collider. Our calculations show that the total cross sections for the $\tilde{t}_1\tildeχ_1^-$ production for the

M. F. M. Lutz

We construct a covariant model for short range correlations of a pion emerged in nuclear matter. Once the delta-hole contribution is considered an additional and so far neglected channel opens that leads to significant modifications in the vicinity of the kinematical region defined by ω\sim |\vec q |. We speculate that this novel effect should be important f

Sugumi Kanno, Misao Sasaki, Jiro Soda

We propose a cosmological braneworld scenario in which two branes collide and emerge as reborn branes whose tensions have signs opposite to the original tensions of the respective branes. In this scenario, gravity on each of the branes is described by a scalar-tensor-type theory in which the radion plays the role of the gravitational scalar, and the branes a

Bret Heinrich, Yaroslav Tserkovnyak, Georg Woltersdorf, Arne Brataas

A long-ranged dynamic interaction between ferromagnetic films separated by normal-metal spacers is reported, which is communicated by nonequilibrium spin currents. It is measured by ferromagnetic resonance (FMR) and explained by an adiabatic spin-pump theory. In FMR the spin-pump mechanism of spatially separated magnetic moments leads to an appreciable incre

Chiu Fan Lee, Neil F. Johnson, Ferney Rodriguez, Luis Quiroga

We discuss the effect of correlated noise on the robustness of quantum coherent phenomena. First we consider a simple, toy model to illustrate the effect of such correlations on the decoherence process. Then we show how decoherence rates can be suppressed using a Parrondo-like effect. Finally, we report the results of many-body calculations in which an exper

Nugzar Makhaldiani

Quantum computers are considered as a part of the family of the reversible, lineary-extended, dynamical systems (Quanputers). For classical problems an operational reformulation is given. A universal algorithm for the solving of classical and quantum problems on quanputers is formulated.

Edward W. Piotrowski

A simple but nontrivial class of the quantum strategies in buying-selling games is presented. The player moves are a rational buying and an unconditional selling. The possibility of gaining extremal profits in such the games is considered. The entangled merchants hypothesis is proposed.

K. W. Yuen, H. T. Fung, K. M. Cheng, M. -C. Chu

We study the general-setting quantum geometric phase acquired by a particle in a vibrating cavity. Solving the two-level theory with the rotating-wave approximation and the SU(2) method, we obtain analytic formulae that give excellent descriptions of the geometric phase, energy, and wavefunction of the resonating system. In particular, we observe a sudden $π

L. E. H. Trainor, Charles J. Lumsden

Interpretations of quantum measurement theory have been plagued by two questions, one concerning the role of observer consciousness and the other the entanglement phenomenon arising from the superposition of quantum states. We emphasize here the remarkable role of quantum statistics in describing the entanglement problem correctly and discuss the relationshi

T. Tatsuno, V. I. Berezhiani, M. Pekker, S. M. Mahajan

Creation of angular momentum in a relativistic electron-positron plasma is explored. It is shown that a chain of angular momentum carrying vortices is a robust asymptotic state sustained by the generalized nonlinear Schrodinger equation characteristic to the system. The results may suggest a possible electromagnetic origin of angular momenta when it is appli

N. Savvinov

We determined the electric form factor of the neutron $G_E^n$ via the reaction ${\vec{d}(\vec{e},e&#39;n)p}$ using a longitudinally polarized electron beam and a frozen, polarized $^{15}ND_3$ target at Jefferson Lab. The knocked out neutrons were detected in a segmented plastic scintillator in coincidence with the quasi-elastically scattered electrons which

Weihua Ruan, M. E. Clark, Meide Zhao, Anthony Curcio

We study a mathematical model of a blood circulation network which is a generalization of the coronary model proposed by Smith, Pullan and Hunter. We prove the existence and uniqueness of the solution to the initial-boundary value problem and discuss the continuity of dependence of the solution and its derivatives on initial, boundary and forcing functions a

D. Cohen, A. Dimca, P. Orlik

We prove a vanishing theorem for the cohomology of the complement of a complex hyperplane arrangement with coefficients in a complex local system. This result is compared with other vanishing theorems, and used to study Milnor fibers of line arrangements, and hypersurface arrangements.

Igor Rivin

In 1957, Chandler Davis proved that unitarily invariant convex functions on the space of hermitian matrices are precisely those which are convex and symmetrically invariant on the set of diagonal matrices. We give a simple perturbation theoretic proof of this result. (Davis&#39; argument was also very short, though based on completely different ideas).

Davoud Kamani

We consider the noncommutativity parameter of the space-time as a bosonic worldsheet field. By finding a fermionic super-partner for it, we can find star products between the boson-boson, boson-fermion and fermion-fermion fields of superstring worldsheet and also between superfields of the worldsheet superspace. We find a two dimensional action for the nonco

M. R. Setare, R. Mansouri

We consider the brane universe in the bulk background of the topological Reissner-Nordström de Sitter black holes. We show that the thermodynamic quantities (including entropy) of the dual CFT take usual special forms expressed in terms of Hubble parameter and its time derivative at the moment, when the brane crosses the black hole horizon or the cosmologica

J. Casahorran

We review the euclidean path-integral formalism in connection with the one-dimensional non-relativistic particle. The configurations which allow to construct a semiclassical approximation classify themselves into either topological (instantons) and non-topological (bounces) solutions. The quantum amplitudes consist on an exponential associated with the class

M. A. Sanchis-Lozano

Leptonic decays of vector-states of bottomonium are analized searching for a light pseudoscalar Higgs-like neutral boson manifesting via an apparent breaking of lepton universality.

S. Hesselbach, F. Franke

We adopt the SUSY benchmark scenario SPS 1a in supersymmetric models where the Higgs sector is extended by singlet superfields. We consider light neutralinos with dominant singlino character whose couplings are generally suppressed. The cross sections for direct production of the singlino-dominated neutralinos can be of the order of several fb for singlet ve

A. Figueiredo, T. M. Rocha Filho, E. Gunzig, L. Brenig

We discuss the implication of the introduction of an extra field to the dynamics of a scalar field conformally coupled to gravitation in a homogeneous isotropic spatially flat universe. We show that for some reasonable parameter values the dynamical effects are similar to those of our previous model with a single scalar field. Nevertheless for other paramete

Esther M. Arkin, Michael A. Bender, Joseph S. B. Mitchell, Steven S. Skiena

We introduce a new class of scheduling problems in which the optimization is performed by the worker (single ``machine&#39;&#39;) who performs the tasks. A typical worker&#39;s objective is to minimize the amount of work he does (he is ``lazy&#39;&#39;), or more generally, to schedule as inefficiently (in some sense) as possible. The worker is subject to the

A. Olemskoi, I. Krakovsky, A. Savelyev

Microphase separated structure consisting of the periodic alternation of the layers of stretched homopolymer chains surrounded by perpendicularly oriented oligomeric tails is studied for both, strongly bonded (ionic) systems and weakly (hydrogen) bonded systems. Our approach is based on the fact that the structure period is determined by alternating associat

P. A. Orellana, F. Dominguez-Adame, I. Gomez, M. L. Ladron de Guevara

A noninteracting quantum-dot array side-coupled to a quantum wire is studied. Transport through the quantum wire is investigated by using a noninteracting Anderson tunneling Hamiltonian. The conductance at zero temperature develops an oscillating band with resonances and antiresonances due to constructive and destructive interference in the ballistic channel

Petr Sobotka, Ondrej Pejcha, Ladislav Smelcer, Pavel Marek

We present visual and CCD VRI observations of a suspected symbiotic binary V335 Vul. Long term photometry suggests usual Mira or SRa pulsations. High speed V band CCD photometry didn&#39;t reveal anything unusual above 0.02 mag.

Patrick Cote

I briefly review models for the formation of globular cluster systems, and summarize the observational properties (i.e., formation efficiencies, metallicity distributions, kinematics and ages) of the globular cluster systems of M87 and M49: two thoroughly studied elliptical galaxies. Many of the properties of the metal-poor clusters in these and other galaxi

John Ellis

Interfaces between high-energy physics, astrophysics and cosmology are reviewed, with particular emphasis on the important roles played by high-energy cosmic-ray physics. These include the understanding of atmospheric neutrinos, the search for massive cold dark matter particles and possible tests of models of quantum gravity. In return, experiments at the LH

K. Kohno, S. Ishizuki, S. Matsushita, B. Vila-Vilaro

The central kpc region of the low luminosity type-1 Seyfert galaxy NGC 1097 has been observed in the CO(1-0) and HCN(1-0) lines with the Nobeyama Millimeter Array and the NRO 45 m telescope. We find a striking enhancement of the HCN emission toward the active nucleus of NGC 1097; a large fraction of the CO emission comes from the circumnuclear starburst ring

Todd A. Brun, Hilary A. Carteret, Andris Ambainis

The quantum random walk has been much studied recently, largely due to its highly nonclassical behavior. In this paper, we study one possible route to classical behavior for the discrete quantum walk on the line: the presence of decoherence in the quantum ``coin&#39;&#39; which drives the walk. We find exact analytical expressions for the time dependence of

J. A. Aguilar-Saavedra, B. M. Nobre

Top flavour-changing neutral decays are extremely suppressed within the Standard Model (SM) by the GIM mechanism, but can reach observable rates in some of its extensions. We compute the branching ratios for t -> c gamma and t -> c g in minimal SM extensions where the addition of a vector-like up or down quark singlet breaks the unitarity of the 3 x 3 Cabibb

A. B. Matsko, I. Novikova, M. S. Zubairy, G. R. Welch

We predict theoretically and demonstrate experimentally an ellipticity-dependent nonlinear magneto-optic rotation of elliptically-polarized light propagating in a coherent atomic medium. We show that this effect results from a hexadecapole and higher order momenta of atomic coherence, and is associated with an enhancement of Kerr and higher orders nonlineari

M. C. Gonzalez-Garcia

In this talk I will review our present knowledge on neutrino masses and mixing trying to emphasize what has been definitively proved and what is in the process of being probed. I will also discuss the most important theoretical implications of these results: the existence of new physics, the estimate of the scale of this new physics as well as some other pos

C. Mendes de Oliveira, C. Da Rocha, C. R. Rabaça, D. N. E. Pereira

Analyses of B and R band observations of four compact groups reveal the presence of a considerable amount of diffuse, intergalactic light in two of them (HCG 79 and HCG 95). The diffuse component is presumably due to stellar material that has been tidally stripped from the galaxy group members. A new approach is used to measure this diffuse background light,

K. Maruyama, P. L. Knight

Universal quantum cloning machines (UQCMs), sometimes called quantum cloners, generate many outputs with identical density matrices, with as close a resemblance to the input state as is allowed by the basic principles of quantum mechanics. Any experimental realization of a quantum cloner has to cope with the effects of decoherence which terminate the coheren

S. Ribault

We compute the density of open strings stretching between AdS2 branes in the Euclidean AdS3. This is done by solving the factorization constraint of a degenerate boundary field, and the result is checked by a Cardy-type computation. We mention applications to branes in the Minkowskian AdS3 and its cigar coset.

V. Belokurov, N. W. Evans

GAIA is the ``super-Hipparcos&#39;&#39; satellite scheduled for launch in 2010 by the European Space Agency. It is a scanning satellite that carries out multi-colour, multi-epoch photometry on all objects brighter than 20th magnitude. We conduct detailed simulations of supernovae (SNe) detection by GAIA. Supernovae of each type are chosen according to the ob

N. Shibata, D. Yoshioka

The ground state of 2D electrons in high magnetic field is studied by the density matrix renormalization group method. The ground state energy, excitation gap, and pair correlation functions are systematically calculated at various fillings in the lowest and the second lowest Landau levels. The ground state phase diagram, which consists of incompressible liq

Hilmar Forkel, Kai Schwenzer

We explore the impact of a resolution-dependent constituent quark mass, as recently applied to diffractive meson production, in QCD correlation functions of several spin-0 and spin-1 meson channels. We compare the resulting correlators with experimental and lattice data, analyze the virtues and limitations of the approach, and discuss the channel dependence

Damir Becirevic, Sasa Prelovsek, Jure Zupan

We study the effects of chiral logs on the heavy-->light pseudoscalar meson transition form factors by using standard and quenched chiral perturbation theory combined with the static heavy quark limit. The resulting expressions are used to indicate the size of uncertainties due to the use of the quenched approximation in the current lattice studies. They may

Marcus Kollar, Ivan Spremo, Peter Kopietz

We derive the low-temperature properties of spin-S quantum Heisenberg magnets from the Gibbs free energy G(M) for fixed order parameter M. Assuming that the low-lying elementary excitations of the system are renormalized spin waves, we show that a straightforward 1/S expansion of G(M) yields qualitatively correct results for the low-temperature thermodynamic

A. Pankiewicz, B. Stefanski

We construct the cubic interaction vertex and dynamically generated supercharges in light-cone superstring field theory in the pp-wave background. We show that these satisfy the pp-wave superalgebra at first order in string coupling. The cubic interaction vertex and dynamical supercharges presented here differ from the expressions previously given in the lit

E. Pierpaoli, S. Borgani, D. Scott, M. White

Different determinations currently suggest scattered values for the power spectrum normalization on the scale of galaxy clusters, sigma_8. Here we concentrate on the constraints coming from the X-ray temperature and luminosity functions (XTF and XLF), and investigate several possible sources of discrepancies in the results. We conclude that the main source o

Tamas Tel, Juergen Vollmer, Laszlo Matyas

In their paper Cohen and Rondoni severely question the physical relevance of studies of transport by means of multibaker maps and other classes of dynamics considering the motion of independen particles - like e.g. the Lorentz gas. We argue that this is to a large extent due to inappropriate interpretation of the models. In particular, the arguments concerni

Kun Yang

We discuss the effects of fluctuations of the local density of charged dopants near a first order phase transition in electronic systems, that is driven by change of charge carrier density controlled by doping level. Using a generalization of the Imry-Ma argument, we find that the first order transition is rounded by disorder at or below the lower critical d

Scott T. Kay, Peter A. Thomas, Tom Theuns

Using hydrodynamical simulations of the LCDM cosmology, that include both radiative cooling and a phenomenological model for star formation and supernovae feedback, we investigate the impact of galaxy formation on the X-ray properties of groups at redshift zero. Motivated by the observed ``break&#39;&#39; in the L_x-T_x relation at kT~1-2keV, our feedback mo

Michihiro Takami, Jeremy Bailey, Antonio Chrysostomou

We present spectro-astrometric observations for 28 southern pre-main sequence (PMS) stars and investigate their circumstellar environment down to AU scales. The structures detected in the ``position spectra&#39;&#39; include: (1) almost all the known binary companions in our sample (Sz 68, Sz 41, HO Lup, VW Cha, S CrA, AS 205), (2) companion candidates which

J. Smit, A. Tranberg

We consider the creation of non-zero Chern-Simons number in a model of the early Universe, where the Higgs field experiences a fast quench at the end of inflation. We perform numerical lattice simulations in the Abelian Higgs model in 1+1 dimensions and in the SU(2)-Higgs model in 3+1 dimensions with an added effective CP-violating term. We also comment on t

Roberto Zucchini

We consider a pure U(1) quantum gauge field theory on a general Riemannian compact four manifold. We compute the partition function with Abelian Wilson loop insertions. We find its duality covariance properties and derive topological selection rules. Finally, we show that, to have manifest duality, one must assume the existence of twisted topological sectors

L. -M. Duan, E. Demler, M. D. Lukin

We describe a general technique that allows to induce and control strong interaction between spin states of neighboring atoms in an optical lattice. We show that the properties of spin exchange interactions, such as magnitude, sign, and anisotropy can be designed by adjusting the optical potentials. We illustrate how this technique can be used to efficiently

Mark Hillery, Jihane Mimih

The problem of unambiguous state discrimination consists of determining which of a set of known quantum states a particular system is in. One is allowed to fail, but not to make a mistake. The optimal procedure is the one with the lowest failure probability. This procedure has been extended to bipartite states where the two parties, Alice and Bob, are allowe

H. Deng, Y. Yamamoto

We investigate the quantum interference effects in two types of matter-wave mixing experiments: one with initial matter waves prepared in independent Fock states (type I) and the other with each individual particle prepared in a same coherent superposition of states (type II). In the type I experiment, a symmetric wavefunction of bosons leads to constructive

Salomon S. Mizrahi, Wagner D. Jose

We propose three schemes to engineer 2^M and M+1 circular states for the motion of the center of mass of a trapped ion, $M$ being the number of laser pulses. Since the ion is subjected to several laser pulses, we analyze the necessary duration of each one for generating the circular states, and from these, the Fock states and superposition of two-Fock states

Shi-Liang Zhu, Z. D. Wang

The nonadiabatic geometric quantum computation may be achieved using coupled low-capacitance Josephson juctions. We show that the nonadiabtic effects as well as the adiabatic condition are very important for these systems. Moreover, we find that it may be hard to detect the adiabatic Berry&#39;s phase in this kind of superconducting nanocircuits; but the non

Cyriaque Genet, Astrid Lambrecht, Serge Reynaud

Vacuum fluctuations have observable consequences, like the Casimir force appearing between two mirrors in vacuum. This force is now measured with good accuracy and agreement with theory. We discuss the meaning and consequences of these statements by emphasizing their relation with the problem of vacuum energy, one of the main unsolved problems at the interfa

Lev B. Levitin, Tommaso Toffoli, Zachary Walton

We consider a quantum gate that complements the state of a qubit and then adds to it an arbitrary phase shift. It is shown that the minimum operation time of the gate is tau = (h/4E)(1+2 theta/pi), where h is Planck&#39;s constant, E is the quantum-mechanical average energy, and theta is the phase shift modulo pi. [We changed the name of a macro file to a mo

Andrew M. Childs, Richard Cleve, Enrico Deotto, Edward Farhi

We construct an oracular (i.e., black box) problem that can be solved exponentially faster on a quantum computer than on a classical computer. The quantum algorithm is based on a continuous time quantum walk, and thus employs a different technique from previous quantum algorithms based on quantum Fourier transforms. We show how to implement the quantum walk

P. C. T. Dajello, I. Mozolevski, Z. G. S. Kipervaser

Heterogeneous nucleation on catalytic surfaces plunged into a fluid is described through a stochastic model. To generate this non-equilibrium process we assume that the turn on of a electrostatic potential triggers a complex dynamics that includes a free Brownian motion, a reaction kinetic and a stimulated migration before the final adhesion of ions on the s

A. F. Borghesani, Peter Lamp

The mobility $μ$ of excess electrons in dense Argon gas has been measured as a function of the applied electric field $E$ and of the gas density N at several temperatures in the range $142.6<T<200$ K, encompassing the critical temperature Tc=150.86 K. We report here measurements at densities up to N?7 nm$^{-3}$, close to the critical density, $N_c \approx$ 8

I. M. Savukov, W. R. Johnson, U. I. Safronova, M. S. Safronova

Energies, transition rates, and electron electric dipole moment (EDM) enhancement factors are calculated for low-lying states of Ce IV and Pr V using relativistic many-body perturbation theory. This study is related to recent investigations of the more complicated Gd IV ion, which is promising for electron EDM experiments. The ions Ce IV and Pr V both have a

P. Muehlich, T. Falter, C. Greiner, J. Lehr

We investigate the consequences of possible medium modifications of the phi meson at finite nuclear matter density on the K+K- mass distribution in photonuclear reactions. The inclusive cross sections for K+K- pair production are calculated within a semi--classical BUU transport model, which combines the initial state interaction of the incoming photon with

L. Canton, G. Pisent, W. Schadow, J. P. Svenne

Pion production at threshold from nucleon-deuteron collisions is considered, with reference to the outgoing channel where the three-nucleon system is bound. The available experimental data are compared with calculations using accurate nuclear wavefunctions coming from rigorous solutions of the three-nucleon quantum mechanical equations. The dominant contribu

E. Oset, D. Jido, J. Palomar, A. Ramos

In this talk a brief review of several problems involving systems with strangeness is made. In the first place one shows how the $Λ(1405)$, $Λ(1670)$ and $Σ(1620)$ states, for $S = -1$, and the $Ξ(1620)$ for $S= -2$ are generated dynamically in the context of unitarized chiral perturbation theory. The results for the $\bar{K}N$ interaction are then used to e

M. Mirea

The Landau--Zener effect is generalized for many-body systems with pairing residual interactions. The microscopic equations of motion are obtained and the $^{14}$C decay of $^{223}$Ra spectroscopic factors are deduced. An asymmetric nuclear shape parametrization given by two intersected spheres is used. The single particle level scheme is determined in the f

Olga Barannikova, Fuqiang Wang

Results are presented on $π^\pm$, $K^\pm$, and $\bar{p}$ transverse mass spectra and particle multiplicity ratios at mid-rapidity in Au+Au collisions at $\sqrt{s_{_{\rm NN}}}$=130 and 200 GeV and in p+p collisions at $\sqrt{s}$=200 GeV. Comparisons are made to results from lower energies. The bulk properties of the collision inferred from these results are d

C. Adler

Azimuthal correlations for large transverse momentum charged hadrons have been measured over a wide pseudo-rapidity range and full azimuth in Au+Au and p+p collisions at $\sqrt{s_{NN}}$ = 200 GeV. The small-angle correlations observed in p+p collisions and at all centralities of Au+Au collisions are characteristic of hard-scattering processes already observe

Javier Castillo

We report preliminary results on the centrality dependence of the $Ξ^{-}$ and $\barΞ^{+}$ production at mid-rapidity in $\sqrt{s_{NN}}=130$ GeV Au+Au collisions from the STAR experiment. For the most central data the obtained yields suggest a saturation of strangeness production per produced hadron. The calculated inverse slope parameter may indicate an earl

Mercedes Lopez Noriega

We present preliminary results from a two-particle intensity interferometry analysis of charged pions and neutral kaons emitted from Au+Au collisions at $\sqrt{s_{NN}}$= 130 and 200 GeV measured in the STAR detector at RHIC. The dependence of the apparent pion source on beam energy, multiplicity, transverse momentum and emission angle with respect to the rea

P. Gaspard, G. Nicolis, J. R. Dorfman

We show that simple diffusive systems, such as the Lorentz gas and multibaker maps are perfectly compatible with the laws of irreversible thermodynamics, despite the fact that the moving particles, or their equivalents, in these models do not interact with each other, and that the dynamics takes place in low-dimensional phase spaces. The interaction of movin

Norbert Peyerimhoff, Ivan Veselić

We consider the Riemannian universal covering of a compact manifold $M = X / Γ$ and assume that $Γ$ is amenable. We show for an ergodic random family of Schrödinger operators on $X$ the existence of a (non-random) integrated density of states.

F. Brau, F. Calogero

New upper and lower limits are given for the number of S-wave bound states yielded by an attractive (monotonic) potential in the context of the Schrodinger or Klein-Gordon equation.

C. Scharlach, L. Vrancken

We study affine immersions as introduced by Nomizu and Pinkall. We classify those affine immersions of a surface in 4-space which are degenerate and have vanishing cubic form (i.e. parallel second fundamental form). This completes the classification of parallel surfaces of which the first results were obtained in the beginning of this century by Blaschke and

José L. Rodríguez, Jérôme Scherer, Antonio Viruel

Often a localization functor (in the category of groups) sends a finite simple group to another finite simple group. We study when such a localization also induces a localization between the automorphism groups and between the universal central extensions. As a consequence we exhibit many examples of localizations of finite simple groups which are not simple

Chandrashekhar Khare, Ian Kiming

Motives and automorphic forms of arithmetic type give rise to Galois representations that occur in {\it compatible families}. These compatible families are of p-adic representations with p varying. By reducing such a family mod p one obtains compatible families of mod p representations. While the representations that occur in such a p-adic or mod p family ar

Chandrashekhar Khare

In this note we produce examples of converging sequences of Galois representations, and study some of their properties. Some of the results here are used in the preprint math.NT/0210296.

Chandrashekhar Khare

In this note we relate the property of a semisimple l-adic Galois representation being &#34;F-split&#34; for a number field F to its having abelian image. By F-split we mean that the characteristic polynomials of Frobenii all split in F.

Bas Edixhoven, Chandrashekhar Khare

Let p be a prime number. The Hasse invariant is a modular form modulo p that is often used to produce congruences between modular forms of different weights. We show how to produce such congruences between forms of weights 2 and p+1, in terms of group cohomology. We also show how our method works in the contexts of quadratic imaginary fields (where there is

Antoine Chambert-Loir

On construit les champs de Hurwitz et on en donne quelques propriétés, essentiellement contenues dans SGA 1. Quelques applications de nature arithmétique en sont déduites. We propose a construction of Hurwitz stacks and give some properties of them, most of which are consequences of SGA 1. Some applications of arithmetic flavor are then deduced.

Maria Teresa Alzugaray

A domain $G\subset \bar\mathbb C$ is the domain of holomorphy of the generating function of a Pólya frequency sequence of order $r$ if and only if it satisfies the following conditions: (A) $G$ contains the point $z=0$, (B) $G$ is symmetric with respect to the real axis, (C) $T=dist(0,\partial G)\in \partial G$.

B. Khesin, G. Misiolek

We show that the following three systems related to various hydrodynamical approximations: the Korteweg--de Vries equation, the Camassa--Holm equation, and the Hunter--Saxton equation, have the same symmetry group and similar bihamiltonian structures. It turns out that their configuration space is the Virasoro group and all three dynamical systems can be reg

Eugene Tokarev

A set of all symmetric Banach function spaces defined on [0,1] is equipped with the partial order by the relation of continuous inclusion. Properties of symmetric spaces, which do not depend of their position in the ordered structure, are studied. With the help of the J. Peetre&#39;s interpolation scheme it is shown that for any pair of symmetric spaces E, F

Eugene Tokarev

W.B. Johnson has constructed a series of Banach spaces non isomorphic to the Hilbert one that have the hereditarily approximation property (shortly hereditarily AP): all their subspaces also have the AP. All these examples were &#39;&#39;sufficiently&#39;&#39; non-symmetric and this fact allows Johnson to ask: whether there exists any Banach space $X$ with s

Aleksander M. Iksanov, Zbigniew J. Jurek

Stationary (limiting) distributions of shot noise processes, with exponential response functions, form a large subclass of positive selfdecomposable distributions that we illustrate by many examples. These shot noise distributions are described among selfdecomposable ones via the regular variation at zero of their distribution functions. However, slow variat

J. M. Camino

In this PhD thesis the low energy effective actions for D-branes and the M5-brane are used to analyze the dynamics of brane probes moving in the geometry created by diverse supergravity backgrounds. It begins with an introduction to string theory. Brane effective actions with local kappa symmetry are also reviewed. We then study the embedding of D(8-p)-brane

Stephen C. Davis

The effects of higher order gravity terms on a dilatonic brane world model are discussed. For a single positive tension flat 3-brane, and one infinite extra dimension, we present a particular class of solutions with finite 4-dimensional Planck scale and no naked singularities. A `self-tuning&#39; mechanism for relaxing the cosmological constant on the brane,

Roberto Iengo, Jorge G. Russo

We study the decay of a very massive closed superstring (i.e. α&#39; M^2>> 1) in the unique state of maximum angular momentum. This is done in flat ten-dimensional spacetime and in the regime of weak string coupling, where the dominant decay channel is into two states of masses M_1, M_2. We find that the lifetime surprisingly grows with the first power of th

Tamiaki Yoneya

The issue of justifying the matrix-theory proposal is revisited. We first discuss how the matrix-string theory is derived directly starting from the eleven dimensional supermembrane wrapped around a circle of radius $R=g_s\ell_s$, without invoking any stringy assumptions, such as S- and T-dualities. This derivation provides us a basis for studying both strin

Peter J. Love, Bruce M. Boghosian

In the 1920&#39;s, Madelung noticed that if the complex Schroedinger wavefunction is expressed in polar form, then its modulus squared and the gradient of its phase may be interpreted as the hydrodynamic density and velocity, respectively, of a compressible fluid. In this paper, we generalize Madelung&#39;s transformation to the quaternionic Schroedinger equ

A. Sirlin

We briefly discuss five topics in Precision Electroweak Physics: i) the recently proposed Effective Scheme of Renormalization, ii) evidence for electroweak bosonic corrections derived from the radiative correction Delta_r_eff, iii) an approach to estimate the scale of new physics in a hypothetical Higgs-less scenario, iv) simple and accurate formulae for s^2

Pedro Ruiz-Femenia

Next-to-next-to-leading contributions to the cross section sigma(e+e- -> tau+tau-) at energies close to threshold are analysed, taking into account the known non-relativistic effects and O(alpha^2) corrections. The numerical changes with respect to previous works are small, but the new corrections give a true estimate of the uncertainty in the theoretical ca

B. F. L. Ward, S. Jadach

We develop and prove the theory of the QCD extension of the YFS Monte Carlo approach to higher order QED radiative corrections. As a corollary, a new approach to quantum gravity by one of us (B.F.L.W.) is illustrated. Semi-analytical results and preliminary explicit Monte Carlo data are presented for the processes p-bar p -> t-bar t + X at FNAL energies. We

Anna Lipniacka

LEP results have constrained heavily the Minimal Supersymmetric Standard Model, while providing hints for light Higgs boson and for ``SUSY-assisted&#39;&#39; gauge couling unification. In this paper the results obtained at LEP within two scenarios, the gravity-mediated MSSM framework and the minimal SUGRA scenario are presented. Model-dependence and coverage