August 2002 arXiv papers — page 7

Uzy Smilansky, Basile Verdene

The correlations in the spectra of quantum systems are intimately related to correlations which are of genuine classical origin, and which appear in the spectra of actions of the classical periodic orbits of the corresponding classical systems. We review this duality and the semiclassical theory which brings it about. The conjecture that the quantum spectral

Michael Forger, Cornelius Paufler, Hartmann Römer

In this note the long standing problem of the definition of a Poisson bracket in the framework of a multisymplectic formulation of classical field theory is solved. The new bracket operation can be applied to forms of arbitary degree. Relevant examples are discussed and important properties are stated with proofs sketched.

Manuel de León, Michael McLean, Larry K. Norris, Angel Rey-Roca

This review paper is concerned with the generalizations to field theory of the tangent and cotangent structures and bundles that play fundamental roles in the Lagrangian and Hamiltonian formulations of classical mechanics. The paper reviews, compares and constrasts the various generalizations in order to bring some unity to the field of study. The generaliza

Kurusch Ebrahimi-Fard

In this brief note we would like to report on an observation concerning the relation between Rota-Baxter operators and Loday-type algebras, i.e. dendriform di- and trialgebras. It is shown that associative algebras equipped with a Rota-Baxter operator of arbitrary weight always give such dendriform structures.

N. H. Ibragimov, V. F. Kovalev, V. V. Pustovalov

Classical Lie group theory provides a universal tool for calculating symmetry groups for systems of differential equations. However Lie's method is not as much effective in the case of integral or integro-differential equations as well as in the case of infinite systems of differential equations. This paper is aimed to survey the modern approaches to sym

Charles P. Boyer, Krzysztof Galicki

We show that #8(S^2 times S^3) admits two 8-dimensional complex families of inequivalent non-regular Sasakian-Einstein structures. These are the first known non-regular Sasakian-Einstein metrics on this 5-manifold.

T. Harima, J. Migliore, U. Nagel, J. Watanabe

Let A = bigoplus_{i >= 0} A_i be a standard graded Artinian K-algebra, where char K = 0. Then A has the Weak Lefschetz property if there is an element ell of degree 1 such that the multiplication times ell : A_i --> A_{i+1} has maximal rank, for every i, and A has the Strong Lefschetz property if times ell^d : A_i --> A_{i+d} has maximal rank for every i and

A. Lebedev, A. Odzijewicz

In the present paper we study the structure of C^*-algebras generated by the components of the polar decompositions of operators in Hilbert space satisfying certain commutation relations.

Janez Mrcun

In this paper we establish a duality between etale Lie groupoids and a class of non-necessarily commutative algebras with a Hopf algebroid structure. For any etale Lie groupoid G over a manifold M, the groupoid algebra C_c(G) of smooth functions with compact support on G has a natural coalgebra structure over C_c(M) which makes it into a Hopf algebroid. Conv

Thomas Foertsch, Viktor Schroeder

Generalizing results due to Brady and Farb we prove the existence of a bilipschitz embedded manifold of pinched negative curvature and dimension m_1+m_2-1 in the product X:=X_1^{m_1} times X_2^{m_2} of two Hadamard manifolds X_i^{m_i} of dimension m_i with pinched negative curvature. Combining this result with a Theorem by Buyalo and Schroeder we prove the a

Andreas Bernig, Thomas Foertsch, Viktor Schroeder

We consider a fairly general class of natural non standard metric products and classify those amongst them, which yield a product of certain type (for instance an inner metric space) for all possible choices of factors of this type (inner metric spaces). We further prove the additivity of the Minkowski rank for a large class of metric products.

Rutwig Campoamor-Stursberg

We analyze the number N of functionally independent generalized Casimir invariants for non-semisimple Lie algebras \frak{s}\overrightarrow{% oplus}_{R}\frak{r} with Levi factors isomorphic to \frak{so}(3) and \frak{sl}(2,R) in dependence of the pair (R,\frak{r}) formed by a representation R of \frak{s} and a solvable Lie algebra \frak{r}. We show that for an

S. Ole Warnaar

A new type of polynomial analogue of the Rogers-Ramanujan identities is proven. Here the product-side of the Rogers-Ramanujan identities is replaced by a partial theta sum and the sum-side by a weighted sum over Schur polynomials.

Donu Arapura

The goal is to verify the Hodge conjecture (and some related conjectures) for certain moduli spaces. It is shown that the (generalized) Hodge conjecture holds for the projective moduli spaces of vector bundles over an abelian or K3 surface or a curve if it holds for all powers of the surface or curve. In the latter case, the curve can be replaced by its Jaco

John H. Brodie

We investigate a system of 1,3, and 7-branes in type IIB string theory. We identify the 1-brane with the vortex of the Abelian Higgs model. We claim that in the S-dual, the theory on the 3-brane confines electric flux which we identify with the fundamental string and that the dual photon has a mass. We then investigate ways of breaking supersymmetry in the b

Miguel D. Bustamante, Sergio A. Hojman

In this paper we consider the general setting for constructing Action Principles for three-dimensional first order autonomous equations. We present the results for some integrable and non-integrable cases of the Lotka-Volterra equation, and we show Lagrangian descriptions which are valid for systems satisfying Shil'nikov criteria on the existence of stra

Jin Hur, Choonkyu Lee

The semiclassical quantization conditions for all partial waves are derived for bound states of two interacting anyons in the presence of a uniform background magnetic field. Singular Aharonov-Bohm-type interactions between the anyons are dealt with by the modified WKB method of Friedrich and Trost. For s-wave bound state problems in which the choice of the

T. A. Larsson

Hence it excludes proton decay and supersymmetry. The main predictions of a gauge model based on the exceptional simple Lie superalgebra mb(3|8) (a localized version of su(3)+su(2)+u(1)) are reviewed.

J. C. da Silva, F. C. Khanna, A. Matos Neto, A. E. Santana

The Bogoliubov transformation in thermofield dynamics, an operator formalism for the finite-temperature quantum-field theory, is generalized to describe a field in arbitrary confined regions of space and time. Starting with the scalar field, the approach is extended to the electromagnetic field and the energy-momentum tensor is written via the Bogoliubov tra

José Antonio Martins Simões

In this paper we propose that the cosmological constant scale and neutrino masses have a common origin: a new spontaneously broken scalar field. This hypothesis is implemented in a 6-space dimensional model that restores the parity symmetry. The 6-dimensional parity symmetry gives a natural mechanism for the smallness of the vacuum energy density.

Debajyoti Choudhury, Dilip Kumar Ghosh, Sourov Roy

We study the signatures of minimal anomaly mediated supersymmetry breaking in an e^- gamma collider. We demonstrate that the associated production of a sneutrino with the lightest chargino leads to a substantially large signal size. The background is negligibly small, though. Even more interestingly, a measurement of the fundamental supersymmetry breaking pa

Tsao Chang

Besides the fact of parity violation in weak interactions, based on evidences from neutrino oscillation and tritium beta decay, a natural conjecture is that neutrinos may be spacelike particles with a tiny proper mass. A Dirac-type equation for spacelike neutrinos is further investigated and its solutions are discussed. This equation can be written in two sp

Jungil Lee

We review predictions, based on the nonrelativistic QCD factorization framework, for the polarizations of prompt J/psi's and Upsilon(nS)'s produced at the Fermilab Tevatron. We also discuss the effect of relativistic corrections on the theoretical prediction for the polarization of prompt J/psi's at the Tevatron.

Jay G. Wacker

In this note we present a review of the little Higgs models that stabilize the electroweak by realizing the Standard Model Higgs as a pseudo-Goldstone boson.

A. Paramonov, A. Rostovtsev

Self-Organized Criticality paradigm is a plausible picture for hadron production. A power-law behavior of hadron transverse momentum spectra and an approximate scaling observed for different hadrons in high energy hadronic collisions are discussed.

P. V. Landshoff

The proton's gluon structure function at small x is larger than nowadays is commonly believed

V. V. Kiselev, A. K. Likhoded

We speculate on a possible interpretation of events selected by the SELEX collaboration and stress an insufficient evidence for the observation of doubly charmed baryon.

Thomas DeGrand

I present first results from an in-progress calculation of B_K in quenched approximation using overlap fermions. My particular implementation of the overlap uses a kernel with nearest and next-nearest neighbor interactions and HYP-blocked gauge connections. Matching to the continuum NDR regularization is done perturbatively. I present preliminary results at

Rafael G. Campos, Eduardo S. Tututi

It is shown that the nonlocal Dirac operator yielded by a lattice model that preserves chiral symmetry and uniqueness of fields, approaches to an ultralocal and invariant under translations operator when the size of the lattice tends to zero.

Artan Borici

In this talk I indroduce lattice fermions with suppressed cutoff modes. Then I present Lanczos based methods for stochastic evaluation of the fermion determinant.

L3 Collaboration

A search for the lightest neutral CP-even and neutral CP-odd Higgs bosons of the Minimal Supersymmetric Standard Model is performed using 216.6 pb-1 of data collected with the L3 detector at LEP at centre-of-mass energies between 203 and 209 GeV. No indication of a signal is found. Including our results from lower centre-of-mass energies, lower limits on the

Maximiliano Ujevic, Patricio S. Letelier

Numerical solutions for: the integral curves of the velocity field (streamlines), the density contours, and the accretion rate of a steady-state flow of an ideal fluid with p=K n^(gamma) equation of state orbiting in a core-dipole-shell system are presented. For 1 < gamma < 2, we found that the non-linear contribution appearing in the partial differential eq

Mario Castagnino, Luis Lara, Olimpia Lombardi

A global definition of time-asymmetry is presented. Schulman&#39;s two arrows of time model is criticized.

Mario Castagnino, Gabriel Catren, Rafael Ferraro

The paper addresses the quantization of minisuperspace cosmological models by studying a possible solution to the problem of time and time asymmetries in quantum cosmology. Since General Relativity does not have a privileged time variable of the newtonian type, it is necessary, in order to have a dynamical evolution, to select a physical clock. This choice y

Yvo Desmedt, Yongge Wang

Achieving secure communications in networks has been one of the most important problems in information technology. Dolev, Dwork, Waarts, and Yung have studied secure message transmission in one-way or two-way channels. They only consider the case when all channels are two-way or all channels are one-way. Goldreich, Goldwasser, and Linial, Franklin and Yung,

Aleksandar Donev, Salvatore Torquato, Frank H. Stillinger, Robert Connelly

Jamming in hard-particle packings has been the subject of considerable interest in recent years. In a paper by Torquato and Stillinger [J. Phys. Chem. B, 105 (2001)], a classification scheme of jammed packings into hierarchical categories of locally, collectively and strictly jammed configurations has been proposed. They suggest that these jamming categories

J. L. O&#39;Brien, A. R. Hamilton, R. G. Clark, C. H. Mielke

We report complex ac magnetic susceptibility measurements of a superconducting transition in very high-quality single-crystal alpha-uranium using microfabricated coplanar magnetometers. We identify an onset of superconductivity at T~0.7 K in both the real and imaginary components of the susceptibility which is confirmed by resistivity data. A superconducting

G. Ouillon, D. Sornette

We propose a new test of the critical earthquake model based on the hypothesis that precursory earthquakes are ``actors&#39;&#39; that create fluctuations in the stress field which exhibit an increasing correlation length as the critical large event becomes imminent. Our approach constitutes an attempt to build a more physically-based cumulative function in

Julien Kockelkoren, Hugues Chaté

The phase transitions to absorbing states of the branching-annihilating reaction-diffusion processes mA --> (m+k)A, nA --> (n-l)A are studied systematically in one space dimension within a new family of models. Four universality classes of non-trivial critical behavior are found. This provides, in particular, the first evidence of universal scaling laws for

A. V. Savin, L. I. Manevitch

The existence of discrete breathers (DBs), or intrinsic localized modes (localized periodic oscillations of transzigzag) is shown. In the localization region periodic contraction-extension of valence C-C bonds occurs which is accompanied by decrease-increase of valence angles. It is shown that the breathers present in thermalized chain and their contribution

D. Reisinger, B. Blass, J. Klein, J. B. Philipp

The use of oxide materials in oxide electronics requires their controlled epitaxial growth. Recently, it was shown that Reflection High Energy Electron Diffraction (RHEED) allows to monitor the growth of oxide thin films even at high oxygen pressure. Here, we report the sub-unit cell molecular or block layer growth of the oxide materials Sr2RuO4, MgO, and ma

Subhradip Ghosh, Paul L. Leath, Morrel H. Cohen

We present the itinerant coherent-potential approximation(ICPA), an analytic, translationally invariant and tractable form of augmented-space-based, multiple-scattering theory in a single-site approximation for harmonic phonons in realistic random binary alloys with mass and force-constant disorder. We provide expressions for quantities needed for comparison

T. Vorrath, S. Debald, B. Kramer, T. Brandes

Phonon cavities are believed to be the next step towards a control of dephasing in semiconductor quantum dot `qubits&#39;. In this paper, we discuss two models for phonon cavities - a surface acoustic wave (SAW) inter-digitated transducer on an infinite half-space, and an elastic thin slab. The inelastic current through double quantum dots in non-perfect SAW

Zohar Nussinov

In this simple note, we suggest a way to rigorously establishing constraints on the form of the ground states of the Hubbard and t-J models and extended longer (yet finite) range variants for various dopings, once exact numerical results are established for these Hamiltonians on finite size clusters with two different (both open and periodic) boundary condit

Zoltán Vörös, Tamás Tasnádi, József Cserti, Péter Pollner

The stability properties of the classical trajectories of charged particles are investigated in a two dimensional stadium-shaped inverse magnetic domain, where the magnetic field is zero inside the stadium domain and constant outside. In the case of infinite magnetic field the dynamics of the system is the same as in the Bunimovich billiard, i.e., ergodic an

Dung-Hai Lee

We introduce the concept that there are two generic classes of Mott insulators in nature. They are distinguished by their responses to weak doping. Doped charges form cluster (i.e. distribute inhomogeneously) in type I Mott insulators while distribute homogeneously in type II Mott insulators. We present our opinion on the role inhomogeneity plays in the cupr

G. Le Bras-Jasmin, Z. Konstantinovic, J. P. Carton, D. Colson

We report magnetic susceptibility performed on overdoped Bi2Sr2CuO6+d powders as a function of oxygen doping d and temperature T. The decrease of the spin susceptibility chis with increasing T is confirmed. At sufficient high temperature, chis presents an unusual linear temperature dependence chis=chis0 -chi1T . Moreover, a linear correlation between chi1 an

A. Fekete, M. Marodi, G. Vattay

In this paper the chaotic properties of the TCP congestion avoidance mechanism are investigated. The analysis focuses on the origin of the complex behavior appearing in deterministic TCP/IP networks. From the traffic modeling point of view the understanding of the mechanism generating chaos is essential, since present models are unable to cope with this phen

S. I. Simdyankin, Normand Mousseau, E. R. Hunt

Stretched exponential distributions and relaxation responses are encountered in a wide range of physical systems such as glasses, polymers and spin glasses. As found recently, this type of behavior occurs also for the distribution function of certain trap time in a number of coupled dynamical systems. We analyze a one-dimensional mathematical model of couple

S. Gluzman, V. I. Yukalov, D. Sornette

The problem of reconstructing functions from their asymptotic expansions in powers of a small variable is addressed by deriving a novel type of approximants. The derivation is based on the self-similar approximation theory, which presents the passage from one approximant to another as the motion realized by a dynamical system with the property of group self-

F. Varnik, L. Bocquet, J. -L. Barrat, L. Berthier

Using molecular dynamics simulations, we show that a simple model of a glassy material exhibits the shear localization phenomenon observed in many complex fluids. At low shear rates, the system separates into a fluidized shear-band and an unsheared part. The two bands are characterized by a very different dynamics probed by a local intermediate scattering fu

Z. Konstantinovic, G. Le Bras-Jasmin, D. Colson, A. Forget

The thermoelectric power S(T) of single-layer Bi2Sr2CuO6+d is studied as a function of oxygen doping in the strongly overdoped region of the phase diagram (T, d). As other physical properties in this region, diffusion thermopower Sdiff(T) also shows an important deviation from conventional Fermi liquid behaviour. This departure from T-linear S(T) dependence

J. A. Porto, P. Johansson, S. P. Apell, T. Lopez-Rios

We develop a theory to study apertureless scanning near-field optical microscopy which takes into account retardation, higher multipoles of the tip, and the multiple scattering between the tip and the surface. We focus on metallic systems and discuss the implication of the formation of tip-induced surface plasmon modes in the tip-surface system. We discuss t

Eric Jeckelmann

The density-matrix renormalization-group (DMRG) method is used to investigate optical excitations in the Mott insulating phase of a one-dimensional extended Hubbard model. The linear optical conductivity is calculated using the dynamical DMRG method and the nature of the lowest optically excited states is investigated using a symmetrized DMRG approach. The n

Li-Bin Fu, Jie Liu, Shi-Gang Chen

The Josephson effects in two weakly linked Bose-Einstein condensates have been studied recently. In this letter, we study the equations derived by Giovanazzi et. al. [Phys. Rev. Lett. 84, 4521 (2000)] focusing on the effects of the initial acceleration and the velocity of the barrier on the ``dc&#39;&#39; current. We find that the dc current has lifetime whi

Gyorgy Szabo, Christoph Hauert

Competition among cooperators, defectors, and loners is studied in an evolutionary prisoner&#39;s dilemma game with optional participation. Loners are risk averse i.e. unwilling to participate and rather rely on small but fixed earnings. This results in a rock-scissors-paper type cyclic dominance of the three strategies. The players are located either on squ

Hiizu Nakanishi

The velocity distribution of inelastic granular gas is examined numerically on two dimensional hard disk system in nearly elastic regime using molecular dynamical simulations. The system is prepared initially in the equilibrium state with the Maxwell-Boltzmann distribution, then after a several inelastic collisions per particle, the system falls in the state

Jihoon Kim, Rakesh K. Singh, Nathan Newman, John M. Rowell

We have investigated the thermodynamic and kinetic barriers involved in the synthesis of MgB2 films. This work refines our initial conjectures predicting optimal MgB2 thin film growth conditions as a consequence of the unusually large kinetic barrier to MgB2 decomposition. The small Mg sticking coefficient at temperatures greater than 300C prevents high temp

Baigeng Wang, Jian Wang, Hong Guo

We propose, theoretically, a new type of quantum field effect transistor that operates purely on the flow of spin current in the absence of charge current. This spin field effect transistor (SFET) is constructed without any magnetic material, but with the help of spin flip mechanism provided by a rotating external magnetic field of uniform strength. The SFET

Ofer Biham, Zhi-Feng Huang, Ofer Malcai, Sorin Solomon

Financial time series typically exhibit strong fluctuations that cannot be described by a Gaussian distribution. In recent empirical studies of stock market indices it was examined whether the distribution P(r) of returns r(tau) after some time tau can be described by a (truncated) Levy-stable distribution L_{alpha}(r) with some index 0 < alpha <= 2. While t

A. V. Rybin, I. P. Vadeiko, G. G. Varzugin, J. Timonen

We study a mechanism of collapse of the condensate wave function in the Gross-Pitaevskii theory with attractive interparticle interaction. We reformulate the Gross-Pitaevskii equation as Newton&#39;s equations for the particle flux and introduce a collapsing fraction of particles. We assume that the collapsing fraction is expelled from the condensate due to

T. Plefka

The dynamic linear response theory of a general Ising model weakly coupled to a heat bath is derived employing the quantum statistical theory of Mori, treating the Hamiltonian of the spin bath coupling as a perturbation, and applying the Markovian approximation. Both the dynamic susceptibility and the relaxation function are expressed in terms of the static

Mousumi Das, Peter J. Teuben, Stuart N. Vogel, Michael W. Regan

We use data from the BIMA Survey of Nearby Galaxies (SONG) to investigate the relationship between ellipticity and central mass concentration in barred spirals. Existing simulations predict that bar ellipticity decreases as inflowing mass driven by the bar accumulates in the central regions, ultimately destroying the bar. Using the ratio of the bulge mass to

A. S. Silbergleit

Recent observational indications of an accelerating universe enhance the interest in studying models with a cosmological constant. We investigate cosmological expansion (FRW metric) with $Λ>0$ for a general linear equation of state $p=wρ$, $w>-1$, so that the interplay between cosmological vacuum and quintessence is allowed, as well. Four closed-form solutio

J. M. Miller, P. Wojdowski, N. S. Schulz, H. L. Marshall

We have analyzed a Chandra HETGS spectrum of the Galactic black hole Cygnus X-1, obtained at a source flux which is approximately twice that commonly observed in its persistent low-intensity, spectrally-hard state. We find a myriad of absorption lines in the spectrum, including Ly-alpha lines and helium-like resonance lines from Ne, Na, Mg, and Si. We calcul

Michael Endl, Martin Kuerster, Frederic Rouesnel, Sebastian Els

With the example of Proxima Centauri we discuss the feasibility of detecting terrestrial planets (1 to a few M_Earth) using the high precision radial velocity (RV) technique. If a very high RV precision for M stars is achieved even planets with these extremely low masses become detectable. For Proxima Cen (M5V), one of the prime targets of our M-stars planet

S. Wolf, F. Gueth, Th. Henning, W. Kley

We investigate the possibility to find evidence for planets in circumstellar disks by infrared and submillimeter interferometry. Hydrodynamical simulations of a circumstellar disk around a solar-type star with an embedded planet of 1 Jupiter mass are presented. On the basis of 3D radiative transfer simulations, images of this system are calculated. These int

James S. Ulvestad, Luis C. Ho

(Abridged) We have searched for nuclear radio emission from a statistically complete sample of 40 Sc galaxies within 30 Mpc that are optically classified as star-forming objects, in order to determine whether weak AGNs might be present. Only three nuclear radio sources were detected, in NGC 864, NGC 4123, and NGC 4535. These galaxies have peak 6-cm radio pow

Fabien Casse, Rony Keppens

We present numerical magnetohydrodynamic (MHD) simulations of a magnetized accretion disk launching trans-Alfvenic jets. These simulations, performed in a 2.5 dimensional time-dependent polytropic resistive MHD framework, model a resistive accretion disk threaded by an initial vertical magnetic field. The resistivity is only important inside the disk, and is

Samuel Boissier, Celine Peroux, Max Pettini

We present a comparison between the observed properties of damped Lyman alpha systems (DLAs) and the predictions of simple models for the evolution of present day disk galaxies, including both low and high surface brightness galaxies. We focus in particular on the number density, column density distribution and gas density of DLAs, which have now been measur

G. F. Marranghello, C. A. Z. Vasconcellos, J. A. de Freitas Pacheco

We review the detectability of gravitational waves generated by oscillations excited during a phase transition from hadronic matter to deconfined quark-gluon matter in the core of a neutron star. Neutron star properties were computed using a Boguta and Bodmer&#39;s based model and the MIT bag model. The maximum energy available to excite mechanical oscillati

Janusz Ziółkowski

A review of basic properties of Be/X-ray binaries is presented. These systems (called also hard X-ray transients), which form the most numerous class of massive X-ray binaries in the Galaxy, are composed of Be stars and neutron stars (X-ray pulsars) on wide (orbital periods 17-263 d), usually eccentric (eccentricities 0.1-0.9) orbits. The systems contain two

B. T. Gaensicke, F. Euchner, S. Jordan

We have identified 7 new magnetic DA white dwarfs in the Early Data Release of the Sloan Digital Sky Survey. Our selection strategy has also recovered all the previously known magnetic white dwarfs contained in the SDSS EDR, KUV03292+0035 and HE0330-0002. Analysing the SDSS fibre spectroscopy of the magnetic DA white dwarfs with our state-of-the-art model sp

E. Olsson, C. J. Pethick

We analyse the effect of non-central forces on the magnetic susceptibility of degenerate Fermi systems. These include the presence of contributions from transitions to states containing more than one quasiparticle-quasihole pair, which cannot be calculated within the framework of Landau Fermi-liquid theory, and renormalization of the quasiparticle magnetic m

Yoshikazu Hashimoto, Yoko Funato, Junichiro Makino

We investigated the orbital evolution of satellite galaxies using numerical simulations. It has been long believed that the orbit suffers circularization due to the dynamical friction from the galactic halo during orbital decay. This circularization was confirmed by numerous simulations where dynamical friction is added as external force. However, some of th

Naohiro Yamazaki, Osamu Kaburaki, Motoki Kino

The effects of a wind on the emerging spectrum from an inefficiently-radiating accretion flow in a global magnetic field are examined, based on the analytic solution obtained recently by one of the present authors. The results exhibit the steepening of the negative slope appearing in the intermediate frequency range of bremsstrahlung spectrum and the decreas

Pei-Ming Ho

In this paper we show that the worldline reparametrization for particles with higher derivative interactions appears as a higher dimensional symmetry, which is generated by the truncated Virasoro algebra. We also argue that for generic nonlocal particle theories the fields on the worldline may be promoted to those living on a two dimensional worldsheet, and

Y. Meurice

We show with two numerical examples that the conventional expansion in powers of the field for the critical potential of 3-dimensional O(N) models in the large-N limit, does not converge for values of phi^2 larger than some critical value. This can be explained by the existence of conjugated branch points in the complex phi^2 plane. Pade approximants [L+3/L]

Stephan Narison

Using Dimensional Regularization (DR) for some two-point functions of a prototype Non-Comutative (NC) ϕ^4 scalar theory in 4-dimensions, we explictly analyze, to one-loop, the IR and UV divergences of non-planar diagrams having quadratic divergences and compare to the case of the Pauli-Villars cut-off regularization (PVR). We also note that the IR structure

B. Dutta, C. S. Kim, Sechul Oh

In the framework of R-parity violating (\rpv) supersymmetry, we try to find a consistent explanation for both recently measured CP asymmetry in B^0 --> phi K_S decay and the large branching ratio of B^{+/-} --> eta&#39; K^{+/-} decay, which are inconsistent with the Standard Model (SM) prediction. We also investigate other charmless hadronic B --> PP and B -

A. V. Stoyanovsky

Generalizations of the Hamilton-Jacobi and Schrodinger equations for multidimensional variational problems of field theory are deduced. These generalizations are so-called variational differential equations.

Yeo-Yie Charng, Kin-Wang Ng, Chi-Yong Lin, Da-Shin Lee

We study the production of photons through the non-equilibrium relaxation of a disoriented chiral condensate formed in the expanding hot central region in ultra-relativistic heavy-ion collisions. It is found that the expansion smoothes out the resonances in the process of parametric amplification such that the non-equilibrium photons are dominant to the ther

Juan Garcia-Bellido, Margarita Garcia Perez, Antonio Gonzalez-Arroyo

We discuss the onset of symmetry breaking from the false vacuum in generic scenarios in which the mass squared of the symmetry breaking (Higgs) field depends linearly with time, as it occurs, via the evolution of the inflaton, in models of hybrid inflation. We show that the Higgs fluctuations evolve from quantum to classical during the initial stages. This j

R. Flume, R. Poghossian

A procedure, allowing to calculate the coefficients of the SW prepotential in the framework of the instanton calculus is presented. As a demonstration explicit calculations for 2, 3 and 4- instanton contributions are carried out.

David Damanik, Dirk Hundertmark, Barry Simon

For Jacobi matrices with a_n = 1+(-1)^n alpha n^{-gamma}, b_n = (-1)^n beta n^{-gamma}, we study bound states and the SzegHo condition. We provide a new proof of Nevai&#39;s result that if gamma > 1/2, the Szego condition holds, which works also if one replaces (-1)^n by cos(mu n). We show that if alpha = 0, beta not equal to 0, and gamma < 1/2, the Szego co

Jeffrey C. Lagarias

D. Bailey and R. E. Crandall recently formulated a &#34;Hypothesis A&#34;, which provides a general principle to explain the (conjectured) normality of constants like pi or log 2 and other related numbers, to base 2 or other integer bases. This paper explains the basic mechanism behind their principle as a connection between single orbits of two different di

Alejandro Rivero

We present some clues to the study of the renormalization group, at graduate level, as well as some bibliographical pointers to classical resources. Just the kind of things one had liked to hear when starting to study the subject.

L. Anguelova, C. I. Lazaroiu

We review our recent work on M-theory compactifications on `toric&#39; G_2 cones, a class of models which generalize those recently considered by Acharya and Witten and lead to chiral matter in four dimensions. We explain our criteria for identifying the gauge group content of such theories and briefly discuss the associated metrics.

E. O. Iltan

We study the charged t-->b W h^0 and t-->b W A^0 decays in the framework of the general two Higgs doublet model, so called model III and beyond. Here, we take the Yukawa couplings complex and introduce a new complex parameter due to the physics beyond the model III, to switch on the CP violating effects. We predict the branching ratios as BR (t--> b W h^0) ~

A. I. Milstein, O. P. Sushkov, I. S. Terekhov

The self-energy and the vertex radiative corrections to the effect of parity nonconservation in heavy atoms are calculated analytically in orders Z alpha^2 and Z^2 alpha^3 ln(lambda_C/r_0), where lambda_C and r_0 being the Compton wavelength and the nuclear radius, respectively. The value of the radiative correction is -0.85% for Cs and -1.41% for Tl. Using

Mushtaq Loan, Michael Brunner, Chris Hamer

Compact U(1) lattice gauge theory in (2+1) dimensions is studied on anisotropic lattices using Standard Path Integral Monte Carlo techniques. We extract the static quark potential and the string tension from 1.0 <= Dtau <= 0.333 simulations at 1.0 <= beta <= 3.0. Estimating the actual value of the renormalization constant, (c = 44), we observe the evidence o

G. Sardanashvily

A relativistic Hamiltonian mechanical system is seen as a conservative Dirac constraint system on the cotangent bundle of a pseudo-Riemannian manifold. We provide geometric quantization of this cotangent bundle where the quantum constraint serves as a relativistic quantum equation.

Morteza Mohseni

The dynamics of pseudo-classical spinning particles in spacetime of gravitational plane waves of general polarization and harmonic profile is studied. The resulting equations of motion are solved exactly and the results are compared with those of the other approaches. The relative accelerations of nearby particles is also calculated.

L. C. Garcia de Andrade

The motion of classical test spinning particles in Godel universe in the realm of Einstein&#39;s General Relativity (GR) is investigated by making use of Killing conserved currents. We consider three distinct cases of motion of spinning particles polarized along the three distinct axes of the anisotropic metric. It is shown that in the case the spin is polar

Alex Verstak, Naren Ramakrishnan, Kyung Kyoon Bae, William H. Tranter

This paper presents a statistical framework for assessing wireless systems performance using hierarchical data mining techniques. We consider WCDMA (wideband code division multiple access) systems with two-branch STTD (space time transmit diversity) and 1/2 rate convolutional coding (forward error correction codes). Monte Carlo simulation estimates the bit e

Mesfin Asfaw, Mulugeta Bekele

A microscopic heat engine is modeled as a Brownian particle in a sawtooh potential (with load) moving through a highly viscous medium driven by the thermal kick it gets from alternately placed hot and cold heat reservoirs. We found closed form expression for the current as a function of the parameters characterizing the model. Depending on the values these m

N. Stefanakis

We present the numerical solutions for the I-V characteristics, and describe the motion of fluxons in a frustrated Josephson junction made of an unconventional triplet superconductor and an s-wave superconductor. In the inline geometry, and long length limit the moving integer fluxon interacts with the bound fractional fluxon but is not able to change its po

Wolfram Brenig

We study the magnetism of a lattice of coupled tetrahedral spin-1/2 clusters which might be of relevance to the tellurate compounds Cu2Te2O5X2, with X=Cl, Br. Using the flow equation method we perform a series expansion in terms of the inter-tetrahedral exchange couplings starting from the quadrumer limit. Results will be given for the magnetic instabilities

Albert Reiner, Gerhard Kahl

Continuing our investigation into the numerical properties of the Hierarchical Reference Theory, we study the square well fluid of range lambda from slightly above unity up to 3.6. After briefly touching upon the core condition and the related decoupling assumption necessary for numerical calculations, we shed some light on the way an inappropriate choice of

Celine Peroux, Patrick Petitjean, Bastien Aracil, R. Srianand

We present chemical abundance measurements in the z_abs=3.35045 Damped Lyman-alpha (DLA) system observed in the UVES spectrum of the BAL quasar BR 1117-1329. We measure a neutral hydrogen column density N(HI)=6.9+/-1.7*10^{20} atoms/cm2 and derive mean abundances relative to solar: [Si/H] = -1.26+/-0.13, [Fe/H]=-1.51+/-0.13, [Ni/H]=-1.57+/-0.13, [Cr/H]=-1.36