August 2003 arXiv papers — page 18

Nestor E. Massa, Cinthia Piamonteze, Helio C. N. Tolentino, Jose Antonio Alonso

We show that in YVO3 new hard phonons gradually become zone center active below ~210 K verifying that a lattice phase transition takes place at about that temperature. The Debye-Waller factor found from EXAFS measurements show an additional disorder below 150K seen as a departure from the thermal behavior. We bring up the similarities of the intermediate pha

A. V. Andreev, I. S. Beloborodov

We derive the $σ$-model for granular metals. It is valid for any relation between the temperature, $T$, and the grain mean level spacing. The continuum limit of the $σ$-model describes non-perturbative charging effects in homogeneous disordered metals. The $σ$-model action contains a novel term which is crucial for studying Coulomb blockade effects. Topologi

J. Aumentado, Mark W. Keller, John M. Martinis, M. H. Devoret

We have fabricated single-Cooper-pair transistors in which the spatial profile of the superconducting gap energy was controlled by oxygen doping. The profile dramatically affects the switching current \textit{vs.} gate voltage curve of the transistor, changing its period from $1e$ to $2e$. A model based on nonequilibrium quasiparticles in the leads explains

K. N. Pham, S. U. Egelhaaf, P. N. Pusey, W. C. K. Poon

We report a detailed experimental study of the structure and dynamics of glassy states in hard spheres with short-range attraction. The system is a suspension of nearly-hard-sphere colloidal particles and non-adsorbing linear polymer which induces a depletion attraction between the particles. Observation of crystallization reveals a re-entrant glass transiti

J. R. L. de Almeida, J. Menche

In this work the properties of minority games containing agents which try to winning all the time are studied by means of computational simulations. We have considered several ways of introducing above the rules clever players using ?strategies? which try to outdo the others endowed with statistically equivalent strategies and compared the resulting behaviou

J. S. Sa Martins, D. Stauffer

Increasing every year the retirement age by the same amount as the increase of the life expectancy gives roughly stable ratios of the number of retired to working-age people in industrialized countries. Continuous influx of immigrants, below one percent per year of the total population, is needed for this stabilization.

Masatsugu Suzuki, Itsuko S. Suzuki

Linear and nonlinear dynamic properties of a reentrant ferromagnet Cu$_{0.2}$Co$_{0.8}$Cl$_{2}$-FeCl$_{3}$ graphite bi-intercalation compound are studied using AC and DC magnetic susceptibility. This compound undergoes successive phase transitions at the transition temperatures $T_{h}$ (= 16 K), $T_{c}$ (= 9.7 K), and $T_{RSG}$ (= 3.5 K). The static and dyna

J. H. Durrell, R. Roessler, M. P. Delamare, J. D. Pedarnig

The high $T_{c}$ cuprate superconductors are noted for their anisotropic layered structure, certain of these materials indeed tend toward the limit of a Lawrence-Doniach superconductor. However, YBa$_2$Cu$_3$O$_{7-δ}$ has a smaller anisotropy than would be expected from its interlayer spacing. This is due to the cuprate chains in the structure. To investigat

C. A. Cardoso, F. M. Araujo-Moreira, M. R. B. Andreeta, A. C. Hernandes

We have grown high-quality single crystals of the colossal-magnetoresistance (CMR) material La0.7Ca0.3MnO3 by using the laser heated pedestal growth (LHPG) method. Samples were grown as fibers of different diameters, and with lengths of the order of centimeters. Their composition and structure were verified through X-ray diffraction, scanning electron microc

Israel D. Vagner

The electron spin transport in condensed matter, Spintronics, is a subject of rapidly growing interest both scientifically and from the point of view of applications to modern and future electronics. In many cases the electron spin transport cannot be described adequately without accounting for the hyperfine interaction between electron and nuclear spins. He

A. K. Huettel, J. Weber, A. W. Holleitner, D. Weinmann

We present measurements on nuclear spin relaxation probed by a single quantum dot in a high-mobility electron gas. Current passing through the dot leads to a spin transfer from the electronic to the nuclear spin system. Applying electron spin resonance the transfer mechanism can directly be tuned. Additionally, the dependence of nuclear spin relaxation on th

Kentaro Nomura, Daijiro Yoshioka

Fractional quantum Hall states in bilayer system at total filling fraction $ν=1/2$ are examined numerically under some ranges of the layer separation and interlayer tunneling. It is shown that the ground state changes continuously from two-component state to one-component state as the interlayer tunneling rate is increased, while the lowest excited state cha

Vitaly N. Golovach, Daniel Loss

We study transport through a double quantum dot, both in the sequential tunneling and cotunneling regimes. Using a master equation approach, we find that, in the sequential tunneling regime, the differential conductance $G$ as a function of the bias voltage $Δμ$ has a number of satellite peaks with respect to the main peak of the Coulomb blockade diamond. Th

Marcelo Marucho, Gustavo A. Carri

In this paper, we present a new approach to the discrete version of the Wormlike Chain Model (WCM) of semiflexible polymers. Our solution to the model is based on a new computational technique called the Generalized Borel Transform (GBT) which we use to study the statistical mechanics of semiflexible polymer chains. Specifically, we evaluate the characterist

ohn R. Dickel, Shiya Wang

The supernova remnant N 157B contains a pulsar and three distinct synchrotron components with rather unusual properties. 1) A somewhat irregular elliptical pulsar wind nebula (PWN) visible in both X-ray and radio wavelengths. The nebula is quite symmetrical with an extent of about 10 X 5 parsecs but offset along the long axis by about 4 pc from the pulsar po

A. T. Steffen, A. J. Barger, L. L. Cowie, R. F. Mushotzky

We investigate how the fraction of broad-line sources in the AGN population changes with X-ray luminosity and redshift. We first construct the rest-frame hard-energy (2-8 keV) X-ray luminosity function (HXLF) at z=0.1-1 using Chandra Lockman Hole-Northwest wide-area data, Chandra Deep Field-North 2 Ms data, other Chandra deep field data, and the ASCA Large S

Philip Massey, K. A. G. Olsen, J. Wm. Parker

We report the discovery of a relatively faint (V=15.5) early-type WN star in the SMC. The line strength and width of He II lambda 4686 emission is similar to that of the other SMC WNs, and the presense of N V lambda 4603,19 emission (coupled with the lack of N III) suggests this star is of spectral type WN3-4.5, and thus is similar in type to the other SMC W

Fred C. Adams, Michael T. Busha, August E. Evrard, Risa H. Wechsler

Astronomical observations strongly suggest that our universe is now accelerating and contains a substantial admixture of dark vacuum energy. Using numerical simulations to study this newly consolidated cosmological model (with a constant density of dark energy), we show that astronomical structures freeze out in the near future and that the density profiles

C. Tappert, R. E. Mennickent, J. Arenas, K. Matsumoto

We present H-alpha line-profile analyses for the seven SU UMa type dwarf novae AK Cnc, WX Cet, AQ Eri, VW Hyi, RZ Leo, TU Men, and HS Vir. All data sets are treated in the same manner, applying a sequence of techniques for each system. The basic ingredients of this sequence are the diagnostic diagram to determine the zero point of the orbital phase, and Dopp

Michiel R. Hogerheijde

The origin of disks surrounding young stars has direct implications for our understanding of the formation of planetary systems. In the interstellar clouds from which star form, angular momentum is regulated by magnetic fields, preventing the spin up of contracting cores. When ~0.03 pc-sized dense cores decouple from the magnetic field and collapse dynamical

Christopher J. Deloye, Lars Bildsten

We discuss the mass-radius (M-R) relations for low-mass (M<0.1 Msun) white dwarfs (WDs) of arbitrary degeneracy and evolved (He, C, O) composition. We do so with both a simple analytical model and models calculated by integration of hydrostatic balance using a modern equation of state valid for fully ionized plasmas. The M-R plane is divided into three regio

Richard de Grijs

The currently available empirical evidence on the star formation processes in the extreme, high-pressure environments induced by galaxy encounters, mostly based on high-resolution Hubble Space Telescope imaging observations, strongly suggests that star CLUSTER formation is an important and perhaps even the dominant mode of star formation in the starburst eve

Jeremy J. Drake

Much of modern astrophysics is grounded on the observed chemical compositions of stars and the diffuse plasma that pervades the space between stars, galaxies and clusters of galaxies. X-ray and EUV spectra of the hot plasma in the outer atmospheres of stars have demonstrated that these environments are subject to chemical fractionation in which the abundance

Jeremy J. Drake

Chandra Low Energy Transmission Grating Spectrograph observations of Algol have been used to determine the abundances of C and N in the secondary star for the first time. The analysis was performed relative to similar observations of an adopted &#34;standard&#34; star HR 1099. It is demonstrated that HR 1099 and Algol are coronal twins in many respects and t

Jeremy J. Drake, Marek J. Sarna

Chandra Low Energy Transmission Grating Spectrograph observations of the pre-cataclysmic binary V471 Tau have been used to estimate the C/N abundance ratio of the K dwarf component for the first time. While the white dwarf component dominates the spectrum longward of 50 AA, at shorter wavelengths the observed X-ray emission is entirely due to coronal emissio

Mathias Th. Keil

We study the flavor-dependent neutrino spectra formation in the core of a supernova (SN) by means of Monte Carlo simulations. A high-statistics neutrino signal from a galactic SN may contain information that severely constrains the parameter space for neutrino oscillations. Therefore, reliable predictions for flavor-dependent fluxes and spectra are urgently

A. Mangalam

Supermassive disks are thought to be precursors of supermassive black holes that are believed to power quasars and exist at centers of galaxies. Formation scenarios of such disks are reviewed and it is argued that gas dynamical schemes are favourable compared to stellar dynamical schemes which could however be important feeding mechanisms for the growth of t

Jean-Francois Lestrade

The most complete catalogue of nearby stars (Gliese and Jarheiss, 1991) has been used to search for the stars whose photospheric thermal emission can be detected by the future millimeter array ALMA. We found that 446 nearby stars with spectral types ranging from A to M are detectable. A long-term astrometric observation programme (> 10 yr) of these stars wit

M. G. Richer, J. A. Lopez, W. Steffen, G. Tovmassian

PN G135.9+55.9 is a compact, high excitation nebula that has been identified recently as the most oxygen-poor halo planetary nebula. Given its very peculiar characteristics and potential implications in the realms of stellar and Galactic evolution, additional data are needed to firmly establish its true nature and evolutionary history. Here we present the fi

I. Andruchow, S. A. Cellone, G. E. Romero, T. P. Dominici

We present results of a microvariability polarization study in the violently variable quasar 3C279. We have resolved the polarization curves in the V band for this object down to timescales of minutes. We found two main components in the evolution of the degree of linear polarization, one consisting of a flicker with timescales of several tens of minutes and

K. S. Cheng

We suggest that some observational features of high-energy radiation from pulsars should be explained in terms of three dimensional geometric models, e.g. the phase-resolved X-ray and $γ$-ray spectra and the energy dependent light curves from various pulsars. In this paper, we present a three dimensional pulsar outer-magnetospheric gap model to explain these

A. Karastergiou, S. Johnston, D. Mitra, A. G. J. van Leeuwen

We present a study of single pulses from nine bright northern pulsars to investigate the behaviour of circular polarisation, V. The observations were conducted with the Effelsberg 100-m radio telescope at 1.41 GHz and 4.85 GHz and the Westerbork radio telescope at 352 MHz. For the first time, we present the average profile of the absolute circular polarisati

Yaoming Shi, W. M. McClain, J. E. Hearst

We find a Lax pair for the geometrically exact discrete Hamiltonian equations for the discrete elastic rod. This is paper III of a series.

Jorge G. Hirsch, Victor Velazquez, Alejandro Frank

The presence of quantum chaos in nuclear mass systematics is analyzed by considering the differences between measured and calculated nuclear masses as a time series described by the power law 1/ f^alpha. While for the liquid droplet model plus shell corrections a quantum chaotic behavior alpha approx 1 is found, errors in the microscopic mass formula have al

C. Anteneodo, S. E. de S. Pinto, A. M. Batista, R. L. Viana

We obtain exact analytical results for lattices of maps with couplings that decay with distance as $r^{-α}$. We analyze the effect of the coupling range on the system dynamics through the Lyapunov spectrum. For lattices whose elements are piecewise linear maps, we get an algebraic expression for the Lyapunov spectrum. When the local dynamics is given by a no

Michael Hutchings

In principle, Floer theory can be extended to define homotopy invariants of families of equivalent objects (e.g. Hamiltonian isotopic symplectomorphisms, 3-manifolds, Legendrian knots, etc.) parametrized by a smooth manifold B. The invariant of a family consists of a filtered chain homotopy type, which gives rise to a spectral sequence whose E^2 term is the

F. W. Stecker

Observations of the multi-TeV spectra of the nearby BL objects Mkn 421 and Mkn 501 exhibit the high energy cutoffs predicted to be the result of intergalactic annihilation interactions, primarily with infrared photons having a flux level as determined by various astronomical observations. After correction for this absorption effect, the derived intrinsic spe

Jason D. Holt, T. T. S. Kuo, G. E. Brown, Scott K. Bogner

There is much current interest in treating low energy nuclear physics using the renormalization group (RG) and effective field theory (EFT). Inspired by this RG-EFT approach, we study a low-momentum nucleon-nucleon (NN) interaction, V_{low-k}, obtained by integrating out the fast modes down the scale ~2fm^{-1}. Since NN experiments can only determine the eff

Tom Farris, Heather E. Logan, Shufang Su

We calculate the cross section for e+e- --> H+ e- nubar in the two-Higgs-doublet model from one-loop diagrams involving top and bottom quarks. This process offers the possibility of producing the charged Higgs boson at the e+e- collider when its mass is more than half the center-of-mass energy, so that charged Higgs pair production is kinematically forbidden

Paul R. Anderson, B. L. Hu

An analytic method is given for deriving the part of the retarded Green&#39;s function v(x,x&#39;) that contributes to the tail term in the radiation reaction force felt by a particle coupled to a massless minimally coupled scalar field. The method gives an expansion of v(x,x&#39;) for small separations of the points x, x&#39; valid for an arbitrary static s

M. Guidal, J. -M. Laget, M. Vanderhaeghen

In view of the numerous experimental results recently released, we provide in this letter an update on the performance of our simple Regge model for strangeness electroproduction on the nucleon. Without refitting any parameters, a decent description of all measured observables and channels is achieved. We also give predictions for spin transfer observables,

V. Barger, D. Marfatia, K. Whisnant

The current status of the physics of massive neutrinos is reviewed with a forward-looking emphasis. The article begins with the general phenomenology of neutrino oscillations in vacuum and matter and documents the experimental evidence for oscillations of solar, reactor, atmospheric and accelerator neutrinos. Both active and sterile oscillation possibilities

J. Kono, G. N. Ostojic, S. Zaric, M. S. Strano

We present results of wavelength-dependent ultrafast pump-probe experiments on micelle-suspended single-walled carbon nanotubes. The linear absorption and photoluminescence spectra of the samples show a number of chirality-dependent peaks, and consequently, the pump-probe results sensitively depend on the wavelength. In the wavelength range corresponding to

Agnes Mocsy, Francesco Sannino, Kimmo Tuominen

We construct an effective Lagrangian which illustrates why color deconfines when chiral symmetry is restored in hot gauge theories with quarks in the fundamental representation. For quarks in the adjoint representation we show that while deconfinement and the chiral transition do not need to coincide, entanglement between them is still present. Extension to

D. Stauffer, H. Meyer-Ortmanns

In the consensus model with bounded confidence, studied by Deffuant et al. (2000), two randomly selected people who differ not too much in their opinion both shift their opinions towards each other. Now we restrict this exchange of information to people connected by a scale-free network. As a result, the number of different final opinions (when no complete c

Florian Schuetz, Marcus Kollar, Peter Kopietz

Using a modified spin-wave approach, we show that in the presence of an inhomogeneous magnetic field or an in plane inhomogeneous electric field a mesoscopic antiferromagnetic Heisenberg ring with integer spin (i.e., a Haldane gap system) exhibits a persistent circulating spin current. Due to quantum fluctuations the current has a finite limit on the order o

S. G. Sharapov, V. P. Gusynin, H. Beck

The quantum magnetic oscillations are studied for planar condensed matter systems with a linear, Dirac-like spectrum of quasiparticle excitations. We derive analytical expressions for magnetic oscillations (de Haas - van Alphen effect) in the density of states, thermodynamic potential, magnetization and chemical potential both for zero and finite temperature

Jacco H. Snoeijer, Thijs. J. H. Vlugt, Martin van Hecke, Wim van Saarloos

An ensemble approach for force distributions in static granular packings is developed. This framework is based on the separation of packing and force scales, together with an a-priori flat measure in the force phase space under the constraints that the contact forces are repulsive and balance on every particle. We show how the formalism yields realistic resu

D. Salgado, J. L. Sanchez-Gomez

Using the Bloch representation of an N-dimensional quantum system and immediate results from quantum stochastic calculus, we establish a closed formula for the Bloch vector, hence also for the density operator, of a quantum system following a Lindblad evolution with selfadjoint Lindblad operators.

A. S. Cornell, Naveen Gaur

The relatively clean theoretical probes of the Standard Model (SM), and the various theories beyond the SM, provided by radiative, semi-leptonic and (purely) leptonic decays of B-mesons have become increasingly important. Due to the large number of possible distributions in the semi-leptonic decays based on the quark level transition $b \to s \ell^+ \ell^-$

Lorenzo Iorio

In this contribution we present two new proposals for measuring the general relativistic gravitomagnetic component of the gravitational field of the Earth. One proposal consists of the measurement of the difference of the rates of the perigee $ψ$ from the analysis of the laser--ranged data of two identical Earth&#39;artificial satellites placed in equal orbi

Takeo Moroi, Tomo Takahashi

We consider cosmic microwave background (CMB) anisotropy in models with quintessence taking into account of isocurvature fluctuation in the quintessence. It is shown that, if the primordial fluctuation of the quintessence has a correlation with the adiabatic density fluctuations, CMB angular power spectrum $C_l$ at low multipoles can be suppressed without af

Oliver Henkel

Applying the Riemann geometric machinery of volume estimates in terms of curvature, bounds for the minimal distance of packings/codes in the Grassmann and Stiefel manifolds will be derived and analyzed. In the context of space-time block codes this leads to a monotonically increasing minimal distance lower bound as a function of the block length. This advoca

Akio K. Inoue, Ryo Yamazaki, Takashi Nakamura

Using the near-infrared (NIR) observations of the afterglows of the high redshift ($5 \la z \la 25$) gamma-ray bursts (GRBs) which will be detected by the {\it Swift} satellite, we discuss a way to study the cosmic reionization history. In principle the details of the cosmic reionization history are well imprinted in the NIR spectra of the GRB afterglows. Ho

Keiichi Wada, Jin Koda

We found that loosely wound spiral shocks in an isothermal gas disk caused by a non-axisymmetric potential are hydrodynamically unstable, if the shocks are strong enough. High resolution, global hydrodynamical simulations using three different numerical schemes, i.e. AUSM, CIP, and SPH, show similarly that trailing spiral shocks with the pitch angle of large

G. Feverati, P. A. Pearce, F. Ravanini

We consider the tricritical Ising model on a strip or cylinder under the integrable perturbation by the thermal $ϕ_{1,3}$ boundary field. This perturbation induces five distinct renormalization group (RG) flows between Cardy type boundary conditions labelled by the Kac labels $(r,s)$. We study these boundary RG flows in detail for all excitations. Exact Ther

Bernd Ammann, Jean-Francois Grosjean, Emmanuel Humbert, Bertrand Morel

Let $(M,g,\si)$ be a compact Riemannian spin manifold of dimension $\geq 2$. For any metric $\tilde g$ conformal to $g$, we denote by $\tildeλ$ the first positive eigenvalue of the Dirac operator on $(M,\tilde g,\si)$. We show that $$\inf_{\tilde{g} \in [g]} \tildeλ\Vol(M,\tilde g)^{1/n} \leq (n/2) \Vol(S^n)^{1/n}.$$ This inequality is a spinorial analogue o

Joel F. Corney, Peter D. Drummond

We introduce the Gaussian quantum operator representation, using the most general multi-mode Gaussian operator basis. The representation unifies and substantially extends existing phase-space representations of density matrices for Bose systems, and also includes generalized squeezed-state and thermal bases. It enables first-principles dynamical or equilibri

P. D. Drummond, P. Deuar, K. V. Kheruntsyan

A technique to simulate the grand canonical ensembles of interacting Bose gases is presented. Results are generated for many temperatures by averaging over energy-weighted stochastic paths, each corresponding to a solution of coupled Gross-Pitaevskii equations with phase-noise. The stochastic gauge method used relies on an off-diagonal coherent-state expansi

A. P. Lund, T. B. Bell, T. C. Ralph

We compare three proposals for non-deterministic C-sign gates implemented using linear optics and conditional measurements with non-ideal ancilla mode production and detection. The simplified KLM gate [Ralph et al, Phys.Rev.A {\bf 65}, 012314 (2001)] appears to be the most resilient under these conditions. We also find that the operation of this gate can be

Paul E. Barclay, Kartik Srinivasan, Matthew Borselli, Oskar Painter

The demonstration of an optical fiber based probe for efficiently exciting the waveguide modes of high-index contrast planar photonic crystal (PC) slabs is presented. Utilizing the dispersion of the PC, fiber taper waveguides formed from standard silica single-mode optical fibers are used to evanescently couple light into the guided modes of a patterned sili

D. E. Chang, Jun Ye, M. D. Lukin

Motivated by the ideas of using cold alkaline earth atoms trapped in an optical lattice for realization of optical atomic clocks, we investigate theoretically the perturbative effects of atom-atom interactions on a clock transition frequency. These interactions are mediated by the dipole fields associated with the optically excited atoms. We predict resonanc

R. G. Unanyan, M. Fleischhauer

A general scheme for an adiabatic geometric phase gate is proposed which is maximally robust against parameter fluctuations. While in systems with SU(2) symmetry geometric phases are usually accompanied by dynamical phases and are thus not robust, we show that in the more general case of a SU(2) x SU(2) symmetry it is possible to obtain a non-vanishing geome

Pavel Krtous

A reformulation of a physical theory in which measurements at the initial and final moments of time are treated independently is discussed, both on the classical and quantum levels. Methods of the standard quantum mechanics are used to quantize boundary phase space to obtain boundary quantum mechanics -- a theory that does not depend on the distinction betwe

Andrei G. Borisov, Sergei V. Shabanov

Wave packet propagation in the basis of interpolating scaling functions (ISF) is studied. The ISF are well known in the multiresolution analysis based on spline biorthogonal wavelets. The ISF form a cardinal basis set corresponding to an equidistantly spaced grid. They have compact support of the size determined by the underlying interpolating polynomial tha

Emilia R. Solano

We review criticality theory as a prelude to consideration of criticality of the Grad-Shafranov equation. Novel criticality conditions of ODEs and PDEs are derived, easily evaluated. The possibility that transport barriers are associated with characteristics of the equilibrium equation is explored. We conjecture that equilibrium criticality permits the appea

K. Lang, D. Ambrose, C. Arroyo, M. Bachman

We describe the design, construction, readout, tests, and performance of planar drift chambers, based on 5 mm diameter copperized Mylar and Kapton straws, used in an experimental search for rare kaon decays. The experiment took place in the high-intensity neutral beam at the Alternating Gradient Synchrotron of Brookhaven National Laboratory, using a neutral

Fedor Simkovic, Larisa Pacearescu, Amand Faessler

The effect of deformation on the two-neutrino double decay (2nbb-decay) for ground state transition 76Ge -> 76Se is studied in the framework of the deformed QRPA with separable Gamow-Teller residual interaction. A new suppression mechanism of the 2nbb-decay matrix element based on the difference in deformations of the initial and final nuclei is included. An

L. Pacearescu, V. Rodin, F. Simkovic, Amand Faessler

The recently proposed Fully-Renormalized QRPA (FR-QRPA), which fullfils the Ikeda sum rule (ISR) exactly, is applied to the two-neutrino double beta decay of $^{76}$Ge, $^{82}$Se, $^{100}$Mo, $^{116}$Cd, $^{128}$Te and $^{130}$Xe. The results obtained are compared with those of other approaches, standard QRPA and self-consistent QRPA (SCQRPA). The similariti

L. V. Fil&#39;kov

The mass formulae for the supernarrow dibaryons and the exotic baryons with small masses are consructed. With this aim their self energies are calculated in one loop approximation using the dispersion relations with two subtractions. The values of the masses obtained in this approach are in a good agreement with the experimental data. The mass formula for th

B. Davids, J. P. M. Beijers, A. M. van den Berg, P. Dendooven

Populating states in 22Mg via the (p,t) reaction in inverse kinematics with a 55 MeV/nucleon 24Mg beam, we have measured the proton-decay branching ratios of the levels at 5.96 MeV and 6.05 MeV and obtained an experimental upper limit on the branching ratio of the 5.71 MeV state. On the basis of the present and previous measurements, we assign spins and pari

Abdul Salam Jarrah, Reinhard Laubenbacher

Given a simplicial complex, it is easy to construct a generic deformation of its Stanley-Reisner ideal. The main question under investigation in this paper is how to characterize the simplicial complexes such that their Stanley-Reisner ideals have Cohen-Macaulay generic deformations. Algorithms are presented to construct such deformations for matroid complex

Federico Camia, Charles M. Newman, Vladas Sidoravicius

We study families of dependent site percolation models on the triangular lattice ${\mathbb T}$ and hexagonal lattice ${\mathbb H}$ that arise by applying certain cellular automata to independent percolation configurations. We analyze the scaling limit of such models and show that the distance between macroscopic portions of cluster boundaries of any two perc

Edwin O&#39;Shea, Rekha R. Thomas

A normal (respectively, graded normal) vector configuration $A$ defines the toric ideal $I_A$ of a normal (respectively, projectively normal) toric variety. These ideals are Cohen-Macaulay, and when $A$ is normal and graded, $I_A$ is generated in degree at most the dimension of $I_A$. Based on this, Sturmfels asked if these properties extend to initial ideal

Sanatan Rai

We deduce the existence of a maximal irreducibility measure for a Markov chain from Zorn&#39;s lemma.

Sei-Qwon Oh

This paper has been withdrawn by the author due a crucial error.

J. Scott Carter, Mohamed Elhamdadi, Matias Graña, Masahico Saito

Three new knot invariants are defined using cocycles of the generalized quandle homology theory that was proposed by Andruskiewitsch and Graña. We specialize that theory to the case when there is a group action on the coefficients. First, quandle modules are used to generalize Burau representations and Alexander modules for classical knots. Second, 2-cocycle

E. Javier Elizondo, Kazuhiko Kurano, Kei-ichi Watanabe

The total coordinate ring TC(X) of a normal variety is a generalization of the ring introduced and studied by Cox in connection with a toric variety. Consider a normal projective variety X with divisor class group Cl(X), and let us assume that it is a finitely generated free abelian group. We define the total coordinate ring of X to be TC(X) = oplus_{D} H^0

Vladimir Chernov

The number $|K|$ of non-isotopic framed knots that correspond to a given unframed knot $K\subset S^3$ is infinite. This follows from the existence of the self-linking number $\slk$ of a zerohomologous framed knot. We use the approach of Vassiliev-Goussarov invariants to construct ``affine self-linking numbers&#39;&#39; that are extensions of $\slk$ to the ca

A. Boulahoual, M. B. Sedra

The main focus of the present work is to study the Feynman&#39;s proof of the Maxwell equations using the NC geometry framework. To accomplish this task, we consider two kinds of noncommutativity formulations going along the same lines as Feynman&#39;s approach. This allows us to go beyond the standard case and discover non-trivial results. In fact, while th

Richard Easther, David Langlois, Roy Maartens, David Wands

We investigate the evolution of gravitational wave perturbations about a brane cosmology embedded in a five-dimensional anti-de Sitter bulk. During slow-roll inflation in a Randall-Sundrum brane-world, the zero mode of the 5-dimensional graviton is generated, while the massive modes remain in their vacuum state. When the zero mode re-enters the Hubble radius

S. S. Xulu

We obtain the energy distribution in the Kerr-Newman metric with the help of Bergmann-Thomson energy-momentum complex. We find that the energy-momentum definitions prescribed by Einstein, Landau-Lifshitz, Papapetrou, Weinberg, and Bergmann-Thomson give the same and acceptable result and also support the {\em Cooperstock Hypothesis} for energy localization in

Stefan Groot Nibbelink, Mark Hillenbach, Tatsuo Kobayashi, Martin G. A. Walter

We investigate the structure of local anomalies of heterotic E_8 x E_8&#39; theory on T^6/Z_4. We show that the untwisted states lead to anomalies in ten, six and four dimensions. At each of the six dimensional fixed spaces of this orbifold the twisted states ensure, that the anomalies factorize separately. As some of these twisted states live on T^2/Z_2, th

E. Kokoulina, V. Nikitin

Collective behaviors of secondary particles in pp-interactions at 70 GeV/c are researched. The Two Stage Gluon Model is supposed for describing of processes with very high multiplicity. It is shown that gluons play the active role in the multiparticle dynamics. Analysis of multiplicity distributions of charged, neutral particles and total multiplicity gives

U. Harbach, S. Hossenfelder, M. Bleicher, H. Stoecker

Modifications of the gyromagnetic moment of electrons and muons due to a minimal length scale combined with a modified fundamental scale M_f are explored. Deviations from the theoretical Standard Model value for g-2 are derived. Constraints for the fundamental scale M_f are given.

Glennys R. Farrar, Gabrijela Zaharijas

We consider 3 types of processes pertinent to the phenomenology of an H di-baryon: conversion of two $Λ$&#39;s in a doubly-strange hypernucleus to an H, decay of the H to two baryons, and -- if the H is light enough -- conversion of two nucleons in a nucleus to an H. We compute the spatial wavefunction overlap using the Isgur-Karl and Bethe-Goldstone wavefun

N. Nasrallah

An old calculation of the s-wave pi-pi scattering lengths is updated and supplemented with experimental data on the pi-pi s-wave phase shift. The results ma0 = .215 and ma2 = -.039 are in excellent agreement with those obtained from a recent analysis of the results published by the Brookhaven E865 collaboration.

Rachel Jeannerot, Jonathan Rocher, Mairi Sakellariadou

We study cosmic string formation within supersymmetric grand unified theories. We consider gauge groups having a rank between 4 and 8. We examine all possible spontaneous symmetry breaking patterns from the GUT down to the standard model gauge group. Assuming standard hybrid inflation, we select all the models which can solve the GUT monopole problem, lead t

Emmanuel A. Paschos, Makoto Sakuda, Ji--Young Yu

We take a fresh look at the analysis of resonance production by neutrinos. We consider three resonances $P_{33}, P_{11}$ and $S_{11}$ with a detailed discussion of their form factors. The article presents results for free proton and neutron targets and discusses the corrections which appear on nuclear targets. The Pauli suppression factor is derived in the F

V. Baru, J. Haidenbauer, C. Hanhart, Yu. Kalashnikova

We study the interesting problem of whether it is possible to distinguish composite from elementary particles. In particular we generalize a model-independent approach of S. Weinberg to the case of unstable particles. This allows us to apply our formalism to the case of the a0(980) and f0(980) resonances and to address the question whether these particles ar

Kh. M. Beshtoev

An approach for examination of gravitational theories using precision measurements of particle lifetime is proposed. The expressions describing dependence of particle lifetime on gravitational potential in Einstein&#39;s and Newton&#39;s gravity theories are obtained. In the case of Newton&#39;s gravity there is a dependence of the particle velocity directio

Zoltan Nagy, Davison E. Soper

We present a subtraction scheme for eliminating the ultraviolet, soft, and collinear divergences in the numerical calculation of an arbitrary one-loop QCD amplitude with an arbitrary number of external legs. The subtractions consist of local counter terms in the space of the four-dimensional loop momentum. The ultraviolet subtraction terms reproduce MSbar re

A. Yu. Ignatiev, G. C. Joshi, B. H. J. McKellar

We report the results of the first computation related to the study of the spectator effects in the rare decay mode $B\to K γγ$ within the framework of Standard Model. It is found that the account of these effects results in the enhancement factor for the short-distance reducible contribution to the branching ratio.

Dan Pirjol, Carlos Schat

The physics of the orbitally excited baryons simplifies drastically in the large Nc limit. The states are arranged into irreducible representations of the contracted SU(4)_c symmetry, with mixing angles determined exactly. The ratios of the strong couplings N* -> [Nπ]_{S,D} are predicted in this limit, with results in agreement with those following from the

Luigi Del Debbio, Haralambos Panagopoulos, Ettore Vicari

We study the spectrum of confining strings in SU(3) pure gauge theory, by means of lattice Monte Carlo simulations, using torelon operators in different representations of the gauge group. Our results provide direct evidence that the string spectrum is according to predictions based on $n$-ality. Torelon correlations in the rank-2 symmetric channel appear to

Costas G. Strouthos

We study the chiral phase transition in (2+1)d strongly coupled U(N) lattice gauge theories with staggered fermions. We show with high precision simulations performed directly in the chiral limit that these models undergo a Berezinski-Kosterlitz-Thouless (BKT) transition. We also show that this universality class is unaffected even in the large N limit.

Kayll Lake

The norms associated with the gradients of the two non-differential invariants of the Kerr vacuum are examined. Whereas both locally single out the horizons, their global behavior is more interesting. Both reflect the background angular momentum as the volume of space allowing a timelike gradient decreases with increasing angular momentum becoming zero in th

Ujjal Debnath, Subenoy Chakraborty

We study the gravitational collapse in ($n+2$)-D quasi-spherical Szekeres space-time (which possess no killing vectors) with dust as the matter distribution. Instead of choosing the radial coordinate `$r$&#39; as the initial value for the scale factor $R$, we consider a power function of $r$ as the initial scale for the radius $R$. We examine the influence o

Hayoung Lee

We study locally spatially homogeneous solutions of the Einstein-Vlasov system with a positive cosmological constant. First the global existence of solutions of this system and the casual geodesic completeness are shown. Then the asymptotic behaviour of solutions in the future time is investigated in various aspects.

A. E. Shalyt-Margolin, A. Ya. Tregubovich

It is done by introducing of an additional term proportional to the interior energy into the standard thermodynamic uncertainty relation that leads to existence of the lower limit of inverse temperature