May 2004 arXiv papers — page 9

S. Maniscalco, J. Piilo, F. Intravaia, F. Petruccione

The dynamics of a typical open quantum system, namely a quantum Brownian particle in a harmonic potential, is studied focussing on its non-Markovian regime. Both an analytic approach and a stochastic wave function approach are used to describe the exact time evolution of the system. The border between two very different dynamical regimes, the Lindblad and no

F. Jugeau, A. Le Yaouanc, L. Oliver, J. -C. Raynal

In a preceeding study in the heavy quark limit of QCD, it has been demonstrated that the best lower bound on the curvature of the Isgur-Wise function Xsi(w) is Xsi"(1) > (4rho2+3(rho2)2) > 15/16. The quadratic term (rho2)2 is dominant in a non-relativistic expansion in the light quark, both Xsi"(1) and (rho2)2 scaling like (R2m2)2, where m is the lig

Pietro Caputo, Gustavo Posta

We study the exponential decay of relative entropy functionals for zero-range processes on the complete graph. For the standard model with rates increasing at infinity we prove entropy dissipation estimates, uniformly over the number of particles and the number of vertices.

Gary A. Mamon, Ewa L. Lokas

Elliptical galaxies are modelled as Sersic luminosity distributions with density profiles (DPs) for the total mass adopted from the DPs of haloes within dissipationless LambdaCDM N-body simulations. Ellipticals turn out to be inconsistent with cuspy low-concentration NFW models representing the total mass, nor are they consistent with a steeper -1.5 inner sl

Steven S. Gubser, Justin Khoury

The mass of a scalar field mediating a fifth force is tightly constrained by experiments. We show, however, that adding a quartic self-interaction for such a scalar makes most tests much less constraining: the non-linear equation of motion masks the coupling of the scalar to matter through the chameleon mechanism. We discuss consequences for fifth force expe

Badis Ydri

Noncommutative U(1) gauge theory in 4-dimensions is shown to be equivalent in some scaling limit to an ordinary non-linear sigma model in 2-dimensions . The model in this regime is solvable and the corresponding exact beta function is found. We also show that classical U(n) gauge theory on {R}^{d-2}{\times}{R}^2_θ can be approximated by a sequence of ordinar

A. A. Shashkin

Experimental results on the metal-insulator transitions and the anomalous properties of strongly interacting two-dimensional electron systems are reviewed and critically analyzed. Special attention is given to recent results for the strongly enhanced spin susceptibility and effective mass in low-disordered silicon MOSFETs.

Andrea R. Rossi, Stefano Olivares, Matteo G. A. Paris

We show how to obtain the photon distribution of a single-mode field using only avalanche photodetectors. The method is based on measuring the field at different quantum efficiencies and then inferring the photon distribution by maximum-likelihood estimation. The convergence of the method and its robustness against fluctuations are illustrated by means of nu

Santosh Ansumali, Iliya V. Karlin, Hans Christian Öttinger

The grand potential for open systems describes thermodynamics of fluid flows at low Mach numbers. A new system of reduced equations for the grand potential and the fluid momentum is derived from the compressible Navier-Stokes equations. The incompressible Navier-Stokes equations are the quasi-stationary solution to the new system. It is argued that the grand

Glenn Merlet

Products of random matrices in the $(\max,+)$ algebra are used as a model for a class of discrete event dynamical systems. J. Mairesse proved that such a system couples in finite times with a unique stationary regime if and only if it has a memory loss property. We prove that the memory loss property is generic in the following sense : if it is not fulfilled

Y. Z. Fan, D. M. Wei, C. F. Wang

In the past two years, tremendous progresses to understand X-ray Flashes have been made. Now it is widely believed that X-ray Flashes and Gamma-ray Bursts are intrinsically the same, their much different peak energy and flux may be just due to our different viewing angles to them. Here we analytically calculate the very early afterglow of X-ray Flashes, i.e.

Kei-ichi Maeda, Nobuyoshi Ohta

We study inflationary solutions in the M-theory. Including the fourth-order curvature correction terms, we find three generalized de Sitter solutions, in which our 3-space expands exponentially. Taking one of the solutions, we propose an inflationary scenario of the early universe. This provides us a natural explanation for large extra dimensions in a brane

Wung-Hong Huang

It is known that in the Minkowski vacuum a bunch of IIA superstrings with D0-branes can be blown-up to a supersymmetric tubular D2-brane, which is supported against collapse by the angular momentum generated by crossed electric and magnetic Born-Infeld (BI) fields. In this paper we show how the multiple, smaller tubes with relative angular momentum could con

Jochen Weller, Jeremiah P Ostriker, Paul Bode, Laurie Shaw

We present an algorithm which is designed to allow the efficient identification and preliminary dynamical analysis of thousands of structures and substructures in large N-body simulations. First we utilise a refined density gradient system (based on DENMAX) to identify the structures, and then apply an iterative approximate method to identify unbound particl

Shunji Matsuura, Alexander. D. Dolgov, Shigehiro Nagataki, Katsuhiko Sato

We study the impact of possible high density baryonic bubbles on the early formed QSO, IGM, and metal poor stars. Such bubbles could be created, under certain conditions, in Affleck-Dine model of baryogenesis and may occupy a relatively small fraction of space, while the dominant part of the cosmological volume has the normal observed baryon-to-photon ratio

D. Protopopescu

Single spin azimuthal asymmetries A_LT' were measured at Jefferson Lab using 2.2 and 4.4 GeV longitudinally polarized electrons incident on He4 and C12 targets in the CLAS detector. A_LT' is related to the imaginary part of the longitudinal-transverse interference and in quasifree nucleon knockout it provides an unambiguous signature for final state

Seung-Il Nam, Atsushi Hosaka, Hyun-Chul Kim

We investigate the production of the newly found pentaquark exotic baryon Xi_5 in the bar{K} N -> K Xi_5 and the bar{K} N -> K* Xi_5 reactions at the tree level. We consider both positive- and negative parities of the Xi_5. The reactions are dominated by the s- and u-channel processes, and the resulting cross sections depend very much on the parity of Xi_5 a

Akinori Tanaka, Masanori Yamanaka

We rigorously prove that an extended Hubbard model with attraction in two dimensions has an unconventional pairing ground state for any electron filling. The anisotropic spin-0 or anisotropic spin-1 pairing symmetry is realized, depending on a phase parameter characterizing the type of local attractive interactions. In both cases the ground state is unique.

Masako Asano, Yasuhiro Sekino

We investigate the holographic correspondence between (p+1)-dimensional ($0\le p\le 4$) SYM theories with 16 supercharges and superstring theories on the near-horizon limit of Dp-brane backgrounds. Following an approach based on the tunneling picture, we study Euclidean superstring semi-classically along null geodesics which connect two points on the boundar

Machiko Hatsuda, Kiyoshi Kamimura

We show that Wess-Zumino terms for D-p branes with p>0 in the Anti-de Sitter (AdS) space are given in terms of "left-invariant" currents on the super-AdS group or the "expanded" super-AdS group. As a result there is no topological extension of the super-AdS algebra. In the flat limit the global Lorentz rotational charges of the AdS space turn

A. Gheorghe, A. A. Raduta

The many $2^k$-pole boson states, $|N_kv_kα_k I_kM_k>$ with $k=2,3$, realize the irreducible representation (IR) for the group reduction chains $SU(2k+1)\supset R_{2k+1}\supset R_3\supset R_2$. They have been analytically studied and widely used for the description of nuclear systems. However, no analytical expression for the degeneracy $d_v(I)$ of the $R_{2

Yungui Gong

The nature of dark energy is a mystery to us. This paper uses the supernova data to explore the property of dark energy by some model independent methods. We first Talyor expanded the scale factor $a(t)$ to find out the deceleration parameter $q_0<0$. This result just invokes the Robertson-Walker metric. Then we discuss several different parameterizations us

K. McKenzie, N. Grosse, W. P. Bowen, S. E. Whitcomb

We demonstrate the generation of broad-band continuous-wave optical squeezing down to 200Hz using a below threshold optical parametric oscillator (OPO). The squeezed state phase was controlled using a noise locking technique. We show that low frequency noise sources, such as seed noise, pump noise and detuning fluctuations, present in optical parametric ampl

Vadim V. Varlamov

Solutions of equations of geodesic deviation in three- and four- dimensional spaces obtained by the inverse scattering transform are considered. It is shown that in the case of three-dimensional space solutions of geodesic deviation equations are reduced to solutions of the well-known Zakharov-Shabat problem. In four- dimensional space system of geodesic dev

Boris M. Chernobrod, Gennady P. Berman, Peter W. Milonni

It is suggested that nano-mechanical cantilevers can be employed as high-Q filters to circumvent laser noise limitations on the sensitivity of frequency modulation spectroscopy. In this approach a cantilever is actuated by the radiation pressure of the amplitude modulated light that emerges from an absorber. Numerical estimates indicate that laser intensity

Boris M. Chernobrod, Gennady P. Berman

We propose a scanning magnetic microscope which has a photoluminescence nanoprobe implanted in the tip of an AFM or STM, or NSOM, and exhibits optically detected magnetic resonance (ODMR). The proposed spin microscope has nanoscale lateral resolution and the single spin sensitivity for AFM and STM.

J. D. Franson

We previously suggested that photon exchange interactions could be used to produce nonlinear effects at the two-photon level, and similar effects have been experimentally observed by Resch et al. (quant-ph/0306198). Here we note that photon exchange interactions are not useful for quantum information processing because they require the presence of substantia

R. -K. Lee, Y. Lai, B. A. Malomed

Two new simple schemes for generating macroscopic (many-photon) continuous-variable entangled states by means of continuous interactions (rather than collisions) between solitons in optical fibers are proposed. First, quantum fluctuations around two time-separated single-component temporal solitons are considered. Almost perfect correlation between the photo

Margarita Ifti, Timothy Killingback, Michael Doebeli

The Prisoner&#39;s Dilemma, a 2-person game in which the players can either cooperate or defect, is a common paradigm for studying the evolution of cooperation, when individuals exhibit variable degrees of cooperation. It is known that in the presence of spatial structure, when individuals ``play against&#39;&#39; their neighbours, and ``compare to&#39;&#39;

T. Pohl, T. Pattard, J. M. Rost

A kinetic approach for the evolution of ultracold neutral plasmas including interionic correlations and the treatment of ionization/excitation and recombination/deexcitation by rate equations is described in detail. To assess the reliability of the approximations inherent in the kinetic model, we have developed a hybrid molecular dynamics method. Comparison

Akira Kageyama, Hantao Ji, Jeremy Goodman, Fei Chen

In preparation for an experimental study of magnetorotational instability (MRI) in liquid metal, we explore Couette flows having height comparable to the gap between cylinders, centrifugally stable rotation, and high Reynolds number. Experiments in water are compared with numerical simulations. Simulations show that endcaps corotating with the outer cylinder

F C Santos, A C Tort

We evaluate the electrostatic potential and the electrostatic field created by a point charge and an arbitrarly oriented electrical dipole placed near a grounded perfectly conducting sphere. Induced surface charge distributions as well as electrostatic energy, force and torque associated with this configuartion are fully discussed. Possible variants of the p

F. Sattin

In this work we review the classical recipe for estimating partial cross sections for electron capture into selected energy levels within the Classical Trajectory Monte Carlo (CTMC) method [R.L. Becker and A.D. MacKellar, J. Phys. B: At. Mol. Phys. 17 (1984) 3923], and point to a deficiency of the method when applied to the CTMC in its r-version, according t

Fabrice Retiere

Flow develops in ultra-relativistic heavy-ion collisions via re-interactions among partons or/and hadrons. Characterizing flow is a crucial step towards understanding the formation of partonic matter. We review new measurements on anisotropic flow, including v2 at large rapidity, v1, v4, and new ways of addressing non-flow issues. We then show the self-consi

Peter Steinberg, PHOBOS collaboration

Recent results from the PHOBOS experiment at RHIC are presented, both from Au+Au collisions from the 2001 run and p+p and d+Au collisions from 2003. The centrality dependence of the total charged particle multiplicity in p+p and d+Au show features, such as Npart-scaling and limiting fragmentation, similar to p+A collisions at lower energies. Multiparticle ph

Peter Steinberg

The basic physical assumptions and results of Landau&#39;s hydrodynamic model of particle production are reviewed. It is argued that these results have a substantial descriptive and predictive power in strong-interaction phenomenology, including recent RHIC data.

Michel Vittot, Cristel Chandre, Guido Ciraolo, Ricardo Lima

We present a method of localised control of chaos in Hamiltonian systems. The aim is to modify the perturbation locally by a small control term which makes the controlled Hamiltonian more regular. We provide an explicit expression for the control term which is able to recreate invariant (KAM) tori without modifying other parts of phase space. We apply this m

N. A. Kudryashov

New approach is presented to search exact solutions of nonlinear differential equations. This method is used to look for exact solutions of the Korteveg -- de Vries -- Burgers equation. New exact solitary waves of the Korteveg -- de Vries -- Burgers equation are found.

B. Feigin, M. Jimbo, T. Miwa, E. Mukhin

Quadratic relations of the intertwiners are given explicitly in two cases of chiral conformal field theory, and monomial bases of the representation spaces are constructed by using the Fourier components of the intertwiners. The two cases are the (p,p&#39;)-minimal series for the Virasoro algebra where 1<p&#39;/p<2, and the level k integrable highest weight

Jozef H. Przytycki, Daniel S. Silver, Susan G. Williams

New obstructions for embedding one compact oriented 3-manifold in another are given. A theorem of D. Krebes concerning 4-tangles embedded in links arises as a special case. Algebraic and skein-theoretic generalizations for 2n-tangles provide invariants that persist in the corresponding invariants of links in which they embed. An example is given of a virtual

Holger Brenner, Georg Hein

We describe the possible restrictions of the cotangent bundle Ω_{\PP^N} to an elliptic curve C \subset \PP^N. We apply this in positive characteristic to the computation of the Hilbert-Kunz function of a homogeneous R_+-primary ideal I \subset R in the graded section ring R = \bigoplus_{n \in \NN} Γ(C, Ø(n)).

Daniel S. Silver, Wilbur Whitten

Any knot group is the image of the group of a prime knot by a homomorphism that preserves peripheral structure. In fact, there are infinitely many such prime knots. A related partial order on knots is defined, and its properties are discussed.

Daniel S. Silver, Susan G. Williams

Alexander group systems for virtual long knots are defined and used to show that any virtual knot is the closure of infinitely many long virtual knots. Manturov&#39;s result that there exists a pair of long virtual knots that do not commute is reproved.

R. D. Arthan

This note describes a representation of the real numbers due to Schanuel. The representation lets us construct the real numbers from first principles. Like the well-known construction of the real numbers using Dedekind cuts, the idea is inspired by the ancient Greek theory of proportion, due to Eudoxus. However, unlike the Dedekind construction, the construc

Michel Hickel

Let $(X,x)$ be a germ of real or complex analytic space and $\mathcal{A}_{(X,x)}$ the space of germs of arcs on $(X,x)$. Let us consider $F_{x}: (X,x) \to (Y,y)$ a germ of a morphism and denote by $\mathcal{F}_{x}: \mathcal{A}_{(X,x)} \to \mathcal{A}_{(Y,y)}$ the induced morphism at the level of arcs. In this paper, we try to emphasize the analogies between

Jean Bérard

We study the asymptotic behavior of a Markov chain on $\mathbb{Z}^2$ that corresponds to the two-dimensional marginals of a reinforcement process on $\mathbb{Z}^{\mathbb{N}}$. Three distinct asymptotic regimes are identified, depending on the scaling of the reinforcement parameter $Δ$ with respect to the number of steps performed by the chain.

Peter Beelen, Irene I. Bouw

This paper concerns towers of curves over a finite field with many rational points, following Garcia--Stichtenoth and Elkies. We present a new method to produce such towers. A key ingredient is the study of algebraic solutions to Fuchsian differential equations modulo $p$. We apply our results to towers of modular curves, and find new asymptotically good tow

Benjamin Nill

We investigate Gorenstein toric Fano varieties by combinatorial methods using the notion of a reflexive polytope which appeared in connection to mirror symmetry. The paper contains generalisations of tools and previously known results for nonsingular toric Fano varieties. As applications we obtain new classification results, bounds of invariants and formulat

Jozef H. Przytycki

We describe in this talk three methods of constructing different links with the same Jones type invariant. All three can be thought as generalizations of mutation. The first combines the satellite construction with mutation. The second uses the notion of rotant, taken from the graph theory, the third, invented by Jones, transplants into knot theory the idea

Andrew Marder

Two generalizations of the Minkowski ?(x) function are given. As ?(x) maps quadratic irrationals to rational numbers, it is shown that both generalizations send natural classes of pairs of cubic irrational numbers in the same cubic number field to pairs of rational numbers. It is also shown that these functions satisfy an analog to the fact that ?(x), while

Serge Tabachnikov

We study closed smooth convex plane curves $Γ$ enjoying the following property: a pair of points $x,y$ can traverse $Γ$ so that the distances between $x$ and $y$ along the curve and in the ambient plane do not change; such curves are called {\it bicycle curves}. Motivation for this study comes from the problem how to determine the direction of the bicycle mo

Hans Christianson

This paper describes new results on the growth and zeros of the Ruelle zeta function for the Julia set of a hyperbolic rational map. It is shown that the zeta function is bounded by $\exp(C_K |s|^δ)$ in strips $|\Re s| \leq K$, where $δ$ is the dimension of the Julia set. This leads to bounds on the number of zeros in strips (interpreted as the Pollicott-Rue

Yoshinori Namikawa

In this paper, we shall prove that any two (projective) symplectic resolutions of a nilpotent orbit closure in a classical simple Lie algebra are connected by a finite sequence of diagrams which are locally trivial families of Mukai flops of type A or of type D. A Mukai flop of type A is the same as a stratified Mukai flop in our previous paper &#34;Mukai fl

Y. -P. Lee

This is an expository paper based on the results in [12] and [16]. The main goal is to prove the following two conjectures for genus up to two. (1) Witten&#39;s conjecture on the relations between higher spin curves and Gelfand-Dickey Hierarchies. (2) Virasoro conjecture for conformal semisimple Frobenius manifolds.

Mark Andrea A. de Cataldo, Luca Migliorini

We give a geometric proof of the Decomposition Theorem of Beilinson, Bernstein, Deligne and Gabber for the direct image of the intersection cohomology complex under a proper map of complex algebraic varieties. The method rests on new Hodge-theoretic results on the cohomology of projective varieties which extend naturally the classical theory and provide new

Michel Boileau, Bernhard Leeb, Joan Porti

This paper has been withdrawn, because its material has been revised and became part of paper math.GT/0010184

U. A. al-Binni, M. S. Shikakhwa

In the presence of an external Aharonov-Bohm potential, we investigate the two QED processes of the emission of a bremsstrahlung photon by an electron, and the production of an electron-positron pair by a single photon. Calculations are carried out using the Born approximation within the framework of covariant perturbation theory to lowest non-vanishing orde

Jarah Evslin

Wrap m D5-branes around the 2-cycle of a conifold, place n D3-branes at a point and watch the system relax. The D5-branes source m units of RR 3-form flux on the 3-cycle, which cause dielectric NS5-branes to nucleate and repeatedly sweep out the 3-cycle, each time gaining m units of D3-charge while the stack of D5-branes loses m units of D3-charge. A similar

T. A. Ioannidou, A. Kouiroukidis, N. D. Vlachos

The properties of Q-balls in the general case of a sixth order potential have been studied using analytic methods. In particular, for a given potential, the initial field value that leads to the soliton solution has been derived and the corresponding energy and charge have been explicitly evaluated. The proposed scheme is found to work reasonably well for al

M. H. Dehghani

In this paper we show that one can have asymptotically de Sitter (dS), anti-de Sitter (AdS) and flat solutions in Gauss-Bonnet gravity without any need to a cosmological constant term in field equations. First, we introduce static solutions whose 3-surfaces at fixed $r$ and $t$ have constant positive ($k=1$), negative ($k=-1$), or zero ($k=0$) curvature. We

T. P. Searight

A theory of degenerate metrics is developed and applied to the problem of unifying gravitation with electromagnetism. The approach is similar to the Kaluza-Klein approach with a fifth dimension, however no ad hoc conditions are needed to explain why the extra dimension is not directly observable under everyday conditions. Maxwell&#39;s theory is recovered wi

G. Bonelli

The paper is withdrawn by the author due to an oversimplified and misleading approach which was taken initially as a starting point.

Maurizio Piai, Aaron Pierce, Jay Wacker

We review how the rho meson can be modeled in an effective theory and discuss the implications of applying this approach to heavier spin-one resonances. Georgi&#39;s vector limit is explored, and its relationship to locality in a deconstructed extra-dimension is discussed. We then apply the formalism for rho&#39;s to strongly coupled theories of electroweak

David London

I review CP violation in the standard model (SM). I also describe the predictions for CP violation in the B system, along with signals for physics beyond the SM. I stress the numerous contributions of Pat O&#39;Donnell to this subject. Finally, I discuss a new method for measuring new-physics parameters in B decays. This knowledge will allow us to partially

Celine Boehm

We study the impact of light gauge bosons on neutrino physics. We show that they can explain the NuTeV anomaly and also escape the constraints from neutrino experiments if they are very weakly coupled and have a mass of a few GeV. Lighter gauge bosons with stronger couplings could explain both the NuTeV anomaly and the positive anomalous magnetic moment of t

E. Oset, T. Hyodo, A. Hosaka, F. J. Llanes-Estrada

In this talk I look into three different topics, addressing first a method to determine the quantum numbers of the $Θ^+$, then exploiting the possibility that the $Θ^+$ is a bound state of $K πN$ and in the third place I present results on a new resonant exotic baryonic state which appears as dynamically generated by the Weinberg Tomozawa $ΔK$ interaction.

S. M. Gerasyuta, V. I. Kochkin

The relativistic five-quark equations are found in the framework of the dispersion relation technique. The five-quark amplitudes for the low-lying pentaquarks including the u,d,s-quarks are calculated. The poles of these amplitudes determine the masses of N- and Xi- pentaquarks. The mass spectra of the lowest pentaquarks with the 1/2+,1/2-,3/2+ are calculate

S. D. Badger, E. W. N. Glover

We present the universal two-loop splitting functions that describe the limits of two-loop $n$-point amplitudes of massless particles when two of the momenta are collinear. To derive the splitting amplitudes, we take the collinear limits of explicit two-loop four-point helicity amplitudes computed in the &#39;t Hooft-Veltman scheme. The $g \to gg$ splitting

T. M. Aliev, M. Savci

We investigate the electromagnetic form factors of the (rho) meson in light cone QCD sum rules. We find that the ratio of the magnetic and charge form factors is larger than two at all values of Q^2, (Q^2 >= 0.5 GeV^2). The values of the individual form factors at fixed values of Q^2 predicted by the light cone QCD sum rules are quite different compared to t

V. Ravindran, J. Smith, W. L. van Neerven

We present the full next-to-next-to-leading order (NNLO) corrections to the coefficient function for the polarized cross section $d Δσ/d Q$ of the Drell-Yan process. We study the effect of these corrections on the process $p+p\to l^+l^-+`X&#39;$ at an C.M. energy $\sqrt{S}=200 GeV$. All QCD partonic subprocesses have been included provided the lepton pair is

Frank Fugel, Bernd A. Kniehl, Matthias Steinhauser

We compute the dominant two-loop electroweak correction, of O(G_F M_t^2), to the partial width of the decay of an intermediate-mass Higgs boson into a pair of photons. We use the asymptotic-expansion technique in order to extract the leading dependence on the top-quark mass plus four expansion terms that describe the dependence on the W- and Higgs-boson mass

M. V. Tokarev

New data on high-pT spectra of J/psi measured by the CDF Collaboration at the Tevatron are analyzed in the framework of z-scaling. F-dependence of z-presentation of the data is used to construct the scaling function of J/psi. The energy independence of the scaling function is used to predict inclusive cross section of prompt J/psi production in bar pp collis

E. Shabalin

The amplitudes of the K^{\pm} \to 3πand K \to 2πdecays are expressed in terms of different combinations of one and the same set of CP-conserving and CP-odd parameters. Extracting the magnitudes of these parameters from the data on K \to 2πdecays, we estimate an expected CP-odd difference between the values of the slope parameters g^+ and g^- of the energy di

L. Roca, J. E. Palomar, E. Oset, H. C. Chiang

We make a theoretical study of the J/Psi decays into ωππ, ϕππ, ωK \bar{K} and ϕK\bar{K} using the techniques of the chiral unitary approach stressing the important role of the scalar resonances dynamically generated through the final state interaction of the two pseudoscalar mesons. We also discuss the importance of new mechanisms with intermediate exchange

A. Jakovac, Zs. Szep

Resummation, ie. reorganization of perturbative series, can result in an inconsistent perturbation theory, unless the counterterms are reorganized in an appropriate way. In this paper two methods are presented for resummation of counterterms: one is a direct method where the necessary counterterms are constructed order by order; the other is a general one, b

H1 Collaboration

A search for scalar top quarks in R-parity violating supersymmetry is performed in e^+ p collisions at HERA using the H1 detector. The data, taken at sqrt{s}=319 GeV and 301 GeV, correspond to an integrated luminosity of 106 pb^-1. The resonant production of scalar top quarks \tilde{t} in positron quark fusion via an R-parity violating Yukawa coupling lambda

ZEUS Collaboration

The beauty production cross section for deep inelastic scattering events with at least one hard jet in the Breit frame together with a muon has been measured, for photon virtualities Q^2 > 2 GeV^2, with the ZEUS detector at HERA using integrated luminosity of 72 pb^-1. The total visible cross section is sigma_b-bbar (ep -> e jet mu X) = 40.9 +- 5.7 (stat.) +

J. Dragic, T. Gershon

We present the first evidence of the decay B0 --> rho0 pi0, using 140fb^-1 of data collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric e+e- collider. We detect a signal with a significance of 3.5 standard deviations, and measure the branching fraction to be Br(B0 ->- rho0 pi0) = (5.1 +/- 1.6(stat) +/- 0.9(syst))*10^-6.

J. -M. Alimi, V. R. Gavrilov, V. N. Melnikov

D-dimensional cosmological model describing the evolution of a multicomponent perfect fluid with variable barotropic parameters in n Ricci-flat spaces is investigated. The equations of motion are integrated for the case, when each component possesses an isotropic pressure with respect to all spaces. Exact solutions are presented in the Kasner-like form. Some

Yves Caseau, Glenn Silverstein, Francois Laburthe

This paper presents a generic technique for improving hybrid algorithms through the discovery of and tuning of meta-heuristics. The idea is to represent a family of push/pull heuristics that are based upon inserting and removing tasks in a current solution, with an algebra. We then let a learning algorithm search for the best possible algebraic term, which r

Yves Caseau, Francois-Xavier Josset, Francois Laburthe

This paper presents a programming language which includes paradigms that are usually associated with declarative languages, such as sets, rules and search, into an imperative (functional) language. Although these paradigms are separately well known and are available under various programming environments, the originality of the CLAIRE language comes from the

Michael J. Maher

Defeasible logic is a rule-based nonmonotonic logic, with both strict and defeasible rules, and a priority relation on rules. We show that inference in the propositional form of the logic can be performed in linear time. This contrasts markedly with most other propositional nonmonotonic logics, in which inference is intractable.

Axel Simon, Andy King

Suppose $<A_i, \vec{c}_i>$ are planar (convex) H-polyhedra, that is, $A_i \in \mathbb{R}^{n_i \times 2}$ and $\vec{c}_i \in \mathbb{R}^{n_i}$. Let $P_i = \{\vec{x} \in \mathbb{R}^2 \mid A_i\vec{x} \leq \vec{c}_i \}$ and $n = n_1 + n_2$. We present an $O(n \log n)$ algorithm for calculating an H-polyhedron $<A, \vec{c}>$ with the smallest $P = \{\vec{x} \in \

Paul Tarau, Veronica Dahl

We describe a scheme for moving living code between a set of distributed processes coordinated with unification based Linda operations, and its application to building a comprehensive Logic programming based Internet programming framework. Mobile threads are implemented by capturing first order continuations in a compact data structure sent over the network.

D Rogulin, F Estrella, T Hauer, R McClatchey

The storage and manipulation of digital images and the analysis of the information held in those images are essential requirements for next-generation medical information systems. The medical community has been exploring collaborative approaches for managing image data and exchanging knowledge and Grid technology [1] is a promising approach to enabling distr

Vasilii Zhakhovskii, Katsunobu Nishihara, Yuko Fukuda, Shinji Shimojo

We develop a new Lagrangian material particle -- dynamical domain decomposition method (MPD^3) for large scale parallel molecular dynamics (MD) simulation of nonstationary heterogeneous systems on a heterogeneous computing net. MPD^3 is based on Voronoi decomposition of simulated matter. The map of Voronoi polygons is known as the Dirichlet tessellation and

Riccardo Pucella, Prakash Panangaden

Recent results of Bucciarelli show that the semilattice of degrees of parallelism of first-order boolean functions in PCF has both infinite chains and infinite antichains. By considering a simple subclass of Sieber&#39;s sequentiality relations, we identify levels in the semilattice and derive inexpressibility results concerning functions on different levels

Alain Barrat, Marc Barthelemy, Alessandro Vespignani

We propose a model for the World Wide Web graph that couples the topological growth with the traffic&#39;s dynamical evolution. The model is based on a simple traffic-driven dynamics and generates weighted directed graphs exhibiting the statistical properties observed in the Web. In particular, the model yields a non-trivial time evolution of vertices and he

K. -W. Lee, W. E. Pickett

The Ni ion in LaNiO$_2$ has the same formal ionic configuration $3d^9$ as does Cu in isostructural CaCuO$_2$, but it is reported to be nonmagnetic and probably metallic whereas CaCuO$_2$ is a magnetic insulator. From ab initio calculations we trace its individualistic behavior to (1) reduced $3d-2p$ mixing due to an increase of the separation of site energie

Igor Erukhimovich

The aim of this paper is two-fold. First, via a phenomenological consideration I show that, equally with the conventional phases (body-centred cubic, hexagonal planar and lamellar), such non-conventional phases as simple cubic, face-centered cubic, well known double gyroid as well as some other phases could be stable in a vicinity of the critical point in th

L. H. Yu, D. Natelson

We report two examples of transport phenomena based on sharp features in the effective density of states of molecular-scale transistors: Kondo physics in C$_{60}$-based devices, and gate-modulated negative differential resistance (NDR) in ``control&#39;&#39; devices that we ascribe to adsorbed contamination. We discuss the need for a statistical approach to

A. Berenov, A. Serquis, X. Z. Liao, Y. T. Zhu

Two sets of MgB2 samples doped with up to 5 at. % of Al were prepared in different laboratories using different procedures. Decreases in the a and c lattice parameters were observed with Al doping confirming Al substitution onto the Mg site. The critical temperature (Tc) remained largely unchanged with Al doping. For 1 - 2.5 at.% doping, at 20K the in-field

W. Wernsdorfer, N. E. Chakov, G. Christou

Simple methods are presented allowing the determination of the magnetic anisotropy axes of a crystal of a single-molecule magnet (SMM). These methods are used to determine an upper bound of the easy axis tilts in a standard Mn12-Ac crystal. The values obtained in the present study are significately smaller than those reported in recent high frequency electro

A. Bansil, D. Nissenbaum, B. Barbiellini, R. Saniz

The magnetization of quantum dots is discussed in terms of a relatively simple but exactly solvable model Hamiltonian. The model predicts oscillations in spin polarization as a function of dot radius for a fixed electron density. These oscillations in magnetization are shown to yield distinct signature in the momentum density of the electron gas, suggesting

B Wemmenhove, T Nikoletopoulos, J P L Hatchett

We apply the cavity method to a spin glass model on a `small world&#39; lattice, a random bond graph super-imposed upon a 1-dimensional ferromagnetic ring. We show the correspondence with a replicated transfer matrix approach, up to the level of one step replica symmetry breaking (1RSB). Using the scheme developed by Mézard & Parisi for the Bethe lattice, we

Arti Dua, Thomas A. Vilgis

We present using simple scaling arguments and one step replica symmetry breaking a theory for the localization of semiflexible polymers in a quenched random environment. In contrast to completely flexible polymers, localization of semiflexible polymers depends not only on the details of the disorder but also on the ease with which polymers can bend. The inte

Alexander V. Zhukov, Shilong Yang, Jianshu Cao

We propose a theory of low temperature thermal transport in nano-wires in the regime where a competition between phonon and flexural modes governs the relaxation processes. Starting with the standard kinetic equations for two different types of quasiparticles we derive a general expression for the coefficient of thermal conductivity. The underlying physics o

W. H. Rippard, M. R. Pufall, S. Kaka, T. J. Silva

We have measured microwave frequency, current-driven magnetization dynamics in point contacts made to Co90Fe10/Cu/ Ni80Fe20 spin valves as a function of applied field strength and angle relative to the film plane. As the field direction is varied from parallel to nearly perpendicular, the device power output increases by roughly two orders of magnitude while

N. Rama, J. B. Philipp, M. Opel, K. Chandrasekaran

We have studied the magnetic properties of Ba_2FeNbO_6 and Ba_2MnNbO_6. it is seen that Ba_2FeNbO_6 is an antiferromagnet with a weak ferromagnetic behaviour at 5K while Ba_2MnNbO_6 shows two magnetic transitions one at 45 K and the other at 12K. Electron spin resonance (ESR) measurements at room temperature show that the Mn compound does not show any Jahn-T

M. V. Milovanovic

We argue that the naively expected singularities of the Fermi surface, in the mixed composite boson - composite fermion states proposed [S.H. Simon et al., PRL 91, 046803(2003)] for the evolution of ν= 1 bilayer quantum Hall system with distance, are obliterated. Our conclusion is based on a careful analysis of the momentum distribution in ν= 1/2 single-laye