October 2003 arXiv papers — page 2

Patrick Koppenburg

We summarise the most recent results of the Belle experiment about flavour changing neutral current (FCNC) radiative and (semi-) leptonic B decays. In particular, we report about the first observation of the decays B->K*l+l-, B->phi K gamma, the inclusive B->Xs l+l-$. We also report about searches for B->l+l- decay and for CP asymmetries in B->K*gamma.

Rolf Seuster

The large data sample accumulated at the KEKB storage ring allows for dedicated analysis in charm spectroscopy. This made the first observations of e.g. the broad D**resonances in B decays as well as other processes possible. The observation of the DsJ resonances are confirmed and indications of their quantum numbers are given. The fragmentation function for

Merced Montesinos

Diffeomorphism covariant theories with dynamical background metric, like gravity coupled to matter fields in the way expressed by Einstein-Hilbert's action or relativistic strings described by Polyakov's action, have `on-shell' vanishing energy-momentum tensor $t_{μν}$ because $t_{μν}$ is, essentially, the Eulerian derivative associated with the

Ajay Patwardhan

Non commutative geometry is creating new possibilities for physics. Quantum spacetime geometry and post inflationary models of the universe with matter creation have an enormous range of scales of time, distance and energy in between. There is a variety of physics possible till the nucleosynthesis epoch is reached. The use of topology and non commutative geo

M. Yu. Kuchiev

The quantum corrections make the black hole capable of reflection: any particle that approaches the event horizon can bounce back in the outside world. The albedo of the black hole depends on its temperature. The reflection shares physical origins with the phenomenon of Hawking radiation; both effects are explained as consequences of the singular nature that

Saibal Ray, Sumana Bhadra, Anand S. Sengupta

Static spherically symmetric anisotropic source has been studied for the Einstein-Maxwell field equations assuming the erstwhile cosmological constant $ Λ$ to be a space-variable scalar, viz., $ Λ= Λ(r) $. Two cases have been examined out of which one reduces to isotropic sphere. The solutions thus obtained are shown to be electromagnetic in origin as a part

Michael R. Dransfield, Victor W. Marek, Miroslaw Truszczynski

In this paper we bring together the areas of combinatorics and propositional satisfiability. Many combinatorial theorems establish, often constructively, the existence of positive integer functions, without actually providing their closed algebraic form or tight lower and upper bounds. The area of Ramsey theory is especially rich in such results. Using the p

Victor W. Marek, Ilkka Niemela, Miroslaw Truszczynski

We investigate mca-programs, that is, logic programs with clauses built of monotone cardinality atoms of the form kX, where k is a non-negative integer and X is a finite set of propositional atoms. We develop a theory of mca-programs. We demonstrate that the operational concept of the one-step provability operator generalizes to mca-programs, but the general

Lengning Liu, Miroslaw Truszczynski

We describe WSAT(cc), a local-search solver for computing models of theories in the language of propositional logic extended by cardinality atoms. WSAT(cc) is a processing back-end for the logic PS+, a recently proposed formalism for answer-set programming.

Lengning Liu, Miroslaw Truszczynski

We study local-search satisfiability solvers for propositional logic extended with cardinality atoms, that is, expressions that provide explicit ways to model constraints on cardinalities of sets. Adding cardinality atoms to the language of propositional logic facilitates modeling search problems and often results in concise encodings. We propose two ``nativ

N. P. Proukakis

We present a model for a continuous atom laser in a one-dimensional waveguide. The beam is formed by continuous Raman outcoupling of a trapped one-dimensional (quasi-)condensate, which is created by imposing a tightly confining transverse optical potential on a three-dimensional magnetically trapped ultracold thermal gas. The trapped (quasi-)condensate is mo

Gloria Platero, Ramon Aguado

In this review we focus on electronic transport through semiconductor nanostructures which are driven by ac fields. Along the review we describe the available experimental information on different nanostructures, like resonant tunneling diodes, superlattices or quantum dots, together with the theoretical tools needed to describe the observed features. These

T. Plefka

Based on the modified Thouless-Anderson-Palmer equations a detailed numerical investigation for the complexity of the Sherrington-Kirkpatrick spin glass is worked out. The data suggest a scaling law which leads to a vanishing of the complexity in the thermodynamic limit as proposed recently. The results for the total number of stable states agree with existi

C. Menotti, A. Smerzi, A. Trombettoni

We investigate the superfluid properties of a Bose-Einstein condensate (BEC) trapped in a one dimensional periodic potential. We study, both analytically (in the tight binding limit) and numerically, the Bloch chemical potential, the Bloch energy and the Bogoliubov dispersion relation, and we introduce {\it two} different, density dependent, effective masses

J. E. Freitas, G. Corso, L. S. Lucena

We study percolation as a critical phenomenon on a multifractal support. The scaling exponents of the the infinite cluster size ($β$ exponent) and the fractal dimension of the percolation cluster ($d_f$) are quantities that seem do not depend on local anisotropies. These two quantities have the same value as in the standard percolation in regular bidimension

L. M. Helme, A. T. Boothroyd, D. Prabhakaran, F. R. Wondre

We report magnetization and neutron scattering measurements of the half-doped compound La$_{1.5}$Sr$_{0.5}$CoO$_4$, which exhibits a checkerboard pattern of charge ordering below ~800K. In the antiferromagnetically-ordered phase below \~40K the spins are found to be canted in the ab plane. The spin excitation spectrum includes spin-wave excitations with a ma

A. L. Carr, J. J. Trafton, S. Dukan, Z. Tesanovic

We present a detailed study of the quasiparticle contribution to the low-temperature specific heat of an extreme type-II superconductor at high magnetic fields. Within a T-matrix approximation for the self-energies in the mixed state of a homogeneous superconductor, the electronic specific heat is a linear function of temperature with a linear-$T$ coefficien

Sergio B. Volchan

A critical examination of some basic conceptual issues in classical statistical mechanics is attempted, with a view to understanding the origins, structure and statuts of that discipline. Due attention is given to the interplay between physical and mathematical aspects, particularly regarding the role of probability theory. The focus is on the equilibrium ca

Matthias Sperl

The correlation functions near higher-order glass-transition singularities are discussed for a schematic two-component model within the mode-coupling theory for ideal glass-transitions. The correlators decay in leading order like $-\ln(t/τ)$ and the leading correction introduces characteristic convex and concave patterns in the decay curves. The time scale $

Antonio J. R. da Silva, A. Fazzio, A. Antonelli

We systematically investigate, using ab initio density-functional theory calculations, the properties of interstitial and substitutional Mn in both Si and Ge, as well as in the Si(1-x)Gex alloy. We show that volume effects are not the main reason Mn prefers to be a subsitutional impurity in pure Ge, and chemical effects, therefore, play an important role. Us

M. N. Popescu, S. Dietrich

Manipulating fluids at the nanoscale within networks of channels or chemical lanes is a crucial challenge in developing small scale devices to be used in microreactors or chemical sensors. In this context, ultra-thin (i.e., monolayer) films, experimentally observed in spreading of nano-droplets or upon extraction from reservoirs in capillary rise geometries,

P. Bryk

A density functional theory for a mixture of hard rods and polymers modeled as chains built of hard tangent spheres is proposed by combining the functional due to Yu and Wu for the polymer mixtures [J. Chem. Phys. {\bf 117}, 2368 (2002)] with the Schmidt's functional [Phys. Rev. E {\bf 63}, 50201 (2001)] for rod-sphere mixtures. As a simple application o

Andreas Schadschneider, Debashish Chowdhury, Alexander John, Katsuhiro Nishinari

Many insects like ants communicate chemically via chemotaxis. This allows them to build large trail systems which in many respects are similar to human-build highway networks. Using a recently proposed stochastic cellular automaton model we discuss the basic properties of the traffic flow on existing trails. Surprisingly it is found that in certain regimes t

E. Zaccarelli, F. Sciortino, S. V. Buldyrev, P. Tartaglia

We evaluate thermodynamic, geometric and dynamic properties of a short-ranged square well binary mixture to provide a coherent picture of this simple, but rich, model for colloidal interactions. In particular, we compare the location, in the temperature-packing fraction plane, of the geometrical percolation locus, the metastable liquid-gas spinodal and the g

M. Zarea, M. Fabrizio, A. A. Nersesyan

Using bosonization approach, we derive an effective low-energy theory for XXZ-symmetric spin-1/2 zigzag ladders and discuss its phase diagram by a variational approach. A spin nematic phase emerges in a wide part of the phase diagram, either critical or massive. Possible crossovers between the spontaneously dimerized and spin nematic phases are discussed, an

A. Fiasconaro, D. Valenti, B. Spagnolo

We present a study of the noise driven escape of an overdamped Brownian particle moving in a cubic potential profile with a metastable state. We analyze the role of the initial conditions of the particle on the enhancement of the average escape time as a function of the noise intensity for fixed and fluctuating potentials. We observe the noise enhanced stabi

D. I. Sirota, A. F. Zhuravlyov

Dislocation waves in magnetic crystals in the vicinity of orientation phase transition (OPT) temperatures are considered in a frame of the field theory of the defects. The singularities of the dislocation flows, elastic deformations and magnetization occur if the magnetic subsystem is inhomogeneous and the dispersion of the media is not taken into account. M

Markus Lazar

By means of linear theory of elastoplasticity, solutions are given for screw and edge dislocations situated in an isotropic solid. The force stresses, strain fields, displacements, distortions, dislocation densities and moment stresses are calculated. The force stresses, strain fields, displacements and distortions are devoid of singularities predicted by th

N. G. Parker, N. P. Proukakis, C. F. Barenghi, C. S. Adams

The motion of a dark soliton is investigated in a one-dimensional dilute Bose-Einstein condensate confined in a harmonic trap and an optical lattice. The harmonic trap induces a dynamical instability of the soliton, culminating in sound emission. The presence of the optical lattice enhances the instability, and in addition, dephases the emitted sound waves,

C. A. Perroni, V. Cataudella, G. De Filippis, G. Iadonisi

Thickness dependence and strain effects in films of $La_{1-x}A_xMnO_3$ perovskites are analyzed in the colossal magnetoresistance regime. The calculations are based on a generalization of a variational approach previously proposed for the study of manganite bulk. It is found that a reduction in the thickness of the film causes a decrease of critical temperat

Manabu Kiguchi, Manabu Nakayama, Kohei Fujiwara, Keiji Ueno

We present a simple but powerful method to determine the thicknesses of the accumulation and depletion layers and the distribution curve of injected carriers in organic field effect transistors. The conductivity of organic semiconductors in thin film transistors was measured in-situ and continuously with a bottom contact configuration, as a function of film

Yue Zhao, Mihail Ionescu, Alexey V. Pan, Shi Xue Dou

The in situ annealing conditions of pulsed laser deposited MgB2 films were studied. The precursor films were deposited at 250 C from a stoichiometric MgB2 target in a 120mTorr Ar atmosphere. The films were then in situ annealed at a temperature from 450 C to 800 C and an annealing time from 1 minute to 10 minutes. We found that the superconducting properties

A. V. Rode, E. G. Gamaly, A. G. Christy, J. G. Fitz Gerald

We report production of nanostructured carbon foam by a high-repetition-rate, high-power laser ablation of glassy carbon in Ar atmosphere. A combination of characterization techniques revealed that the system contains both sp2 and sp3 bonded carbon atoms. The material is a novel form of carbon in which graphite-like sheets fill space at very low density due

Masaru Kato, Masayuki Ako, Masahiko Machida, Tomio Koyama

We have developed a numerical method that calculated superconducting states and magnetic field distributions for the composite structures of the High-Tc superconductor and the conventional superconductor in arbitrary geometries. We show spontaneous magnetic flux appears at the corner of the boundary of these two superconductors. Also we propose High-Tc super

G. E. Astrakharchik, D. Blume, S. Giorgini, B. E. Granger

We study the behavior of quasi-one-dimensional (quasi-1d) Bose gases by Monte Carlo techniques, i.e., by the variational Monte Carlo, the diffusion Monte Carlo, and the fixed-node diffusion Monte Carlo technique. Our calculations confirm and extend our results of an earlier study [Astrakharchik et al., cond-mat/0308585]. We find that a quasi-1d Bose gas i) i

K. Y. Michael Wong, S. W. Lim, Zhuo Gao

We consider a version of large population games whose agents compete for resources using strategies with adaptable preferences. Diversity among the agents reduces their maladpative behavior. We find interesting scaling relations with diversity for the variance of decisions. When diversity increases, the scaling dynamics is modified by kinetic sampling and wa

G. Baskaran

`Quantum Charge Liquid&#39;(QCL), a new phase, is proposed to describe anomalous metallic properties (T < 100 K)of a density &#39;y&#39; of doped holes with strong coulomb repulsions, in a band insulator NaCoO$_2$ with N sites. This phase, a quantum melted charge order, is characterized by a `charge only&#39; fermi-sea (cFS) of yN charges and a `soft spin-li

A. K. Aringazin, M. I. Mazhitov

We make a comparative analysis of some recent one-dimensional Langevin models of the acceleration of a Lagrangian fluid particle in developed turbulent flow. The class of models characterized by random intensities of noises (RIN models) provides a fit to the recent experimental data on the acceleration statistics. We review the model by Laval, Dubrulle, and

Steven Furlanetto, Joop Schaye, Volker Springel, Lars Hernquist

We use a high-resolution cosmological simulation to predict the distribution of HI Ly-alpha emission from the low-redshift (z<0.5) intergalactic medium (IGM). Our simulation can be used to reliably compute the emission from optically thin regions of the IGM but not that of self-shielded gas. We therefore consider several models that bracket the expected emis

F. Halzen

Kilometer-scale neutrino detectors such as IceCube are discovery instruments covering nuclear and particle physics, cosmology and astronomy. Examples of their multidisciplinary missions include the search for the particle nature of dark matter and for additional small dimensions of space. In the end, their conceptual design is very much anchored to the obser

Rafael Angel Araya-Gochez

We examine the possibility that hyper-accretion onto newly born, black holes occurs in highly intermittent, non-asymmetric fashion favorable to gravitational wave emission in a neutrino cooled disk. This picture of near-hole accretion is motivated by magneto-rotationally induced, ultra-relativistic disk dynamics in the region of the flow bounded from below b

B. J. Anthony-Twarog, B. A. Twarog

CCD photometry on the uvbyCaHbeta system is presented for the open cluster, NGC 3680. Restricting the data to probable cluster members using the CMD and the photometric indices alone defines a sample of 34 stars at the cluster turnoff that imply E(b-y)=0.042(0.002) or E(B-V) = 0.058(0.003), where the errors (s.e.m) refer to internal errors alone. With this r

Rien van de Weygaert, Ravi Sheth

Within the context of hierarchical scenarios of gravitational structure formation we describe how an evolving hierarchy of voids evolves on the basis of {\em two} processes, the {\em void-in-void} process and the {\it void-in-cloud} process. The related analytical formulation in terms of a {\it two-barrier} excursion problem leads to a self-similarly evolvin

John Ellis

A National Research Council study on connecting quarks with the cosmos has recently posed a number of the more important open questions at the interface between particle physics and cosmology. These questions include the nature of dark matter and dark energy, how the Universe began, modifications to gravity, the effects of neutrinos on the Universe, how cosm

Daniel Burkey, Andy Taylor

We develop new methods to study the properties of galaxy redshift surveys and radial peculiar velocity surveys, both individually and combined. We derive the Fisher information matrix for redshift surveys, including redshift distortions and stochastic bias. We find exact results for estimating the marginalised accuracy of a two-parameter measurement of the a

John Ellis

Big-Bang cosmology and ideas for possible physics beyond the Standard Model of particle physics are introduced. The density budget of the Universe is audited, and the issues involved in calculating the baryon density from microphysics are mentioned, as is the role of cold dark matter in the formation of cosmological structures. Candidates for cold dark matte

Laure Barriere-Fouchet, Jean-Francois Gonzalez, Robin J. Humble, Sarah T. Maddison

We present the results of three-dimensional numerical simulations that include the effects of hydrodynamical forces and gas drag upon an evolving dusty gas disk. We briefly describe a new parallel, two phase numerical code based upon the smoothed particle hydrodynamics (SPH) technique in which the gas and dust phases are represented by two distinct types of

Henk Hoekstra

Weak gravitational lensing of distant galaxies by foreground structures has proven to be a powerful tool to study the mass distribution in the universe. The advent of panoramic cameras on 4m class telescope has led to a first generation of surveys that already compete with large redshift surveys in terms of the accuracy with which cosmological parameters can

John D. Silverman, Paul J. Green, Thomas L. Aldcroft, Dong-Woo Kim

We present an X-ray and optical analysis of a 2-8 keV flux limited (fx > 10e-14 erg s^-1 cm^-2) sample of 126 AGN detected in 16 Chandra fields. This work represents a small though significant subset of the Chandra Multiwavelength Project (ChaMP). We have chosen this limiting flux to have a reasonable degree of completeness (50%) in our optical spectroscopic

Belinda J. Wilkes

Active Galactic Nuclei (AGN) are multiwavelength emitters. To have any hope of understanding them, or even to determine their energy output, we must observe them with many telescopes. I will review what we have learned from broad-band observations of relatively bright, low-redshift AGN over the past 15 years. AGN can be found at all wavelengths but each prov

Konrad Kuijken

I report on an ongoing programme of proper motion measurements in the Galactic Bulge, using HST images. As a first application, the data are used to derive the vertical gravitational acceleration on the minor axis of the Galaxy. Implications of the measurement for the flattening of the Galactic potential are discussed.

Isabella Pagano, Jeffrey L. Linsky, Jeff Valenti, Douglas K. Duncan

We describe and analyze HST/STIS observations of the G2 V star alpha Centauri A (alpha Cen A, HD 128620), a star similar to the Sun. The high resolution echelle spectra obtained with the E140H and E230H gratings cover the complete spectral range 1133-3150 Angstrom with a resolution of 2.6 km/s, an absolute flux calibration accurate to +/-5%, and an absolute

N. G. Douglas, A. J. Romanowsky, K. Kuijken, M. R. Merrifield

A new instrument is providing crucial data with which to probe the structure of dark halos in elliptical galaxies.

Elena Torri, Massimo Meneghetti, Matthias Bartelmann, Lauro Moscardini

We study the impact of merger events on the strong lensing properties of galaxy clusters. Previous lensing simulations were not able to resolve dynamical time scales of cluster lenses, which arise on time scales which are of order a Gyr. In this case study, we first describe qualitatively with an analytic model how some of the lensing properties of clusters

Allan D. Ernest

Certain solutions to a gravitational form of Schrodinger&#39;s equation can yield stable, macroscopic eigenstate solutions having no classical analogue, with properties resembling those of dark matter. Some more tractable solutions show: (1) radiative lifetimes far exceeding the universe&#39;s age, implying negligible emission and inherent stability w.r.t. g

V. Ferrari, L. Gualtieri, J. A. Pons, A. Stavridis

In this paper we study the effects of rotation on the frequencies of the quasi-normal modes of a proto-neutron star (PNS) born in a gravitational collapse during the first minute of life. Our analysis starts a few tenths of seconds after the PNS formation, when the stellar evolution can be described by a sequence of equilibrium configurations. We use the evo

Michal Chodorowski, Pawel Ciecielag

We reexamine likelihood analyses of the Local Group (LG) acceleration, paying particular attention to nonlinear effects. Under the approximation that the joint distribution of the LG acceleration and velocity is Gaussian, two quantities describing nonlinear effects enter these analyses. The first one is the coherence function, i.e. the cross-correlation coef

A. Moya, R. Garrido, M. A. Dupret

Phase differences and amplitude ratios at different colour photometric bands are currently being used to discriminate pulsation modes in order to facilitate mode identification of kappa-driven non-radial pulsating stars. In addition to physical inputs (e.g., mass, T_eff, etc.), these quantities depend on the non-adiabatic treatment of the atmosphere. This pa

Y. Z. Fan, Z. G. Dai, D. M. Wei

For High frequency BL Lac objects (HBLs) like H1426+428, a significant fraction of their TeV gamma-rays emitted are likely to be absorbed in interactions with the diffuse IR background, yielding $e^\pm$ pairs. The resulting $e^\pm$ pairs generate one hitherto undiscovered GeV emission by inverse Compton scattering with the cosmic microwave background photons

V. F. Dmitriev, V. V. Flambaum, J. K. Webb

We use Big Bang Nucleosynthesis calculations and light element abundance data to constrain the relative variation of the deuteron binding energy since the universe was a few minutes old, $δQ = Q(BBN)-Q(present)$. Two approaches are used, first treating the baryon to photon ratio, $η$, as a free parameter, but with the additional freedom of varying $δQ$, and

L. J. Dursi, M. Zingale

Block-structured AMR meshes are often used in astrophysical fluid simulations, where the geometry of the domain is simple. We consider potential efficiency gains for time sub-cycling, or time refinement (TR), on Berger-Collela and oct-tree AMR meshes for explicit or local physics (such as explict hydrodynamics), where the work per block is roughly constant w

Rupert A. C. Croft

We investigate the large-scale inhomogeneities of the hydrogen ionizing radiation field in the Universe at redshift z=3. Using a raytracing algorithm, we simulate a model in which quasars are the dominant sources of radiation. We make use of large scale N-body simulations of a LambdaCDM universe, and include such effects as finite quasar lifetimes and output

Nils Erland L. Haugen, Axel Brandenburg, Wolfgang Dobler

Nonhelical hydromagnetic turbulence without an imposed magnetic field is considered in the case where the magnetic Prandtl number is unity. The magnetic field is entirely due to dynamo action. The magnetic energy spectrum peaks at a wavenumber of about 5 times the minimum wavenumber in the domain, and not at the resistive scale, as has previously been argued

Emanuel Gallo

In this article we extend to higher dimensional space-times a recent theorem proved by Salgado which characterizes a three-parameter family of static and spherically symmetric solutions to the Einstein Field Equations. As it happens in four dimensions, it is shown that the Schwarzschild, Reissner-Nordstrom and global monopole solutions in higher dimensions a

Darren S. Madgwick, Paul Hewett, Daniel Mortlock, Lifan Wang

We present the results of a novel new search of the first data-release from the Sloan Digital Sky Survey (SDSS-DR1) for the spectra of supernovae. The use of large spectroscopic galaxy surveys offers the prospect of obtaining improved estimates of the local supernova rate, with the added benefit of a very different selection function to that of conventional

Amit Khetan

We give the first exact determinantal formula for the resultant of an unmixed sparse system of four Laurent polynomials in three variables with arbitrary support. This follows earlier work by the author on exact formulas for bivariate systems and also uses the exterior algebra techniques of Eisenbud and Schreyer. Along the way we will prove an interesting ne

C. V. Ciobanu, D. T. Tambe, V. B. Shenoy

Although the clean Si(001) and Ge(001) surfaces are very similar, experiments to date have shown that dimer-vacancy (DV) defects self-organize into vacancy lines (VLs) on Si(001), but not on Ge(001). In this paper, we perform empirical-potential calculations aimed at understanding the differences between the vacancies on Si(001) and Ge(001). We identify thre

S. Larochelle, M. Greven

We calculate the uniform and staggered susceptibilities of two-chain spin-1/2 Heisenberg ladders using Monte-Carlo simulations. We show that the gap extracted from the uniform susceptibility and the saturation value of the staggered susceptibility are independent of the sign of the inter-chain coupling J_perp in the asymptotic limit |J_perp|/J -> 0. Furtherm

V. Cirigliano, G. Ecker, H. Neufeld, A. Pich

We perform a complete analysis of isospin breaking in K -> Pi Pi amplitudes in chiral perturbation theory, including both strong isospin violation and electromagnetic corrections to next-to-leading order in the low-energy expansion. The unknown chiral couplings are estimated at leading order in the 1/N_c expansion. We study the impact of isospin breaking on

N. J. Nunes, James E. Lidsey

The possibility of reconstructing the dark energy equation of state from variations in the fine structure constant is investigated for a class of models where the quintessence field is non-minimally coupled to the electromagnetic field. For given classes of couplings and quintessence interaction potentials, it is typically found that variations in alpha woul

Qiang Zhao

We carry out an analysis of the pentaquark $Θ^+$ photoproduction with polarized photon beams. Kinematical and dynamical aspects are examined for the purpose of determining $Θ^+$&#39;s spin and parity. It shows that the polarized photon beam asymmetry in association with certain dynamical properties of the production mechanism would provide further informatio

Thomas Callaghan, Peter J. Mucha, Mason A. Porter

Each December, college football fans and pundits across America debate which two teams should meet in the NCAA Division I-A National Championship game. The Bowl Championship Series (BCS) standings employed to select the teams invited to this game are intended to provide an unequivocal #1 v. #2 game for the championship; however, this selection process has it

Diego Chialva, Roberto Iengo, Jorge G. Russo

We find a one-parameter family of long-lived physical string states in type II superstring theory. We compute the decay rate by an exact numerical evaluation of the imaginary part of the one-loop propagator. Remarkably, the lifetime rapidly increases with the mass. We find a power-law dependence of the form $T = const. g^{-2} Mass^α$, where the value of $α$

Kiyotomo Ichiki, Kouji Nakamura

The causal structure of the flat brane universe of RSII type is re-investigated to clarify the boundary conditions for stochastic gravitational waves. In terms of the Gaussian normal coordinate of the brane, a singularity of the equation for gravitational waves appears in the bulk. We show that this singularity corresponds to the ``seam singularity&#39;&#39;

Ulrike Kraemmer, Anton Rebhan

The progress of the last decade in perturbative quantum field theory at high temperature and density made possible by the use of effective field theories and hard-thermal/dense-loop resummations in ultrarelativistic gauge theories is reviewed. The relevant methods are discussed in field theoretical models from simple scalar theories to non-Abelian gauge theo

Gary T. Horowitz, Juan Maldacena

We propose that in quantum gravity one needs to impose a final state boundary condition at black hole singularities. This resolves the apparent contradiction between string theory and semiclassical arguments over whether black hole evaporation is unitary.

Jerrold Franklin

A general three quark bound state satisfying the Pauli principle, and conserving angular momentum and isospin, is used to investigate the spin structure of nucleons at high $x$. It is shown if {$F_{1n}/F_{1p}$$\to$1/4}, then both $A_{1p}$ and $A_{1n}$, as well as quark spin distribution $Δu/u$, will approach 1 as $x$$\to$1 in polarized deep inelastic scatter

Diego S. Ledesma, Mauricio Bellini

We discuss a semiclassical treatment to inflationary models from Kaluza-Klein theory without the cylinder condition. We conclude that the evolution of the early universe could be described by a geodesic trayectory of a cosmological 5D metric here proposed, so that the effective 4D FRW background metric should be a hypersurface on a constant fifth dimension.

F. Bardou, L. Jaeger

By defining the phenotype of a biopolymer by its active three-dimensional shape, and its genotype by its primary sequence, we propose a model that predicts and characterizes the statistical distribution of a population of biopolymers with a specific phenotype, that originated from a given genotypic sequence by a single mutational event. Depending on the rati

Koujin Takeda, Hidetoshi Nishimori

We study the four-dimensional Z_2 random-plaquette lattice gauge theory as a model of topological quantum memory, the toric code in particular. In this model, the procedure of quantum error correction works properly in the ordered (Higgs) phase, and phase boundary between the ordered (Higgs) and disordered (confinement) phases gives the accuracy threshold of

G. Kaniadakis, A. M. Scarfone

The Lesche stability condition for the Shannon entropy [B. Lesche, J. Stat. Phys. 27, 419 (1982)], represents a fundamental test, for its experimental robustness, for systems obeying the Maxwell-Boltzmann statistical mechanics. Of course, this stability condition must be satisfied by any entropic functional candidate to generate non-conventional statistical

Thorsten Renk

The common interpretation of HBT data measured at top SPS energies leads to apparent source lifetimes of 6-8 fm/c and emission duration of approximately 2-3 fm/c. We investigate a scenario with continuous pion emission from a long-lived (~17 fm/c) thermalized source in order to show that it is not excluded by the data. Starting from a description of the sour

Sebastien Fromang, Steven A. Balbus, Jean-Pierre De Villiers

In this paper and a companion work, we report on the first global numerical simulations of self-gravitating magnetized tori, subject in particular to the influence of the magnetorotational instability (MRI). In this work, paper I, we restrict our calculations to the study of the axisymmetric evolution of such tori. Our goals are twofold: (1) to investigate h

Germano D&#39;Abramo

The Mind-Body Problem, which constitutes the starting point for a large part of the speculations about consciousness and conscious experience, can be re-stated in an equivalent way, using the `brain duplication&#39; argument described in this paper. If we assume that consciousness follows from a peculiar organization of physical matter and energy, namely tha

Raishma Krishnan, A. M. Jayannavar

We study the nature of currents, input energy and entropy production in different types of adiabatically rocked ratchets using the method of stochastic energetics. The currents exhibit a peak as a function of noise strength. We show that there is no underlying resonance or synchronisation phenomena in the dynamics of the particle with these current peaks. Th

P. Anastasopoulos, A. B. Hammou, N. Irges

We analyze non-supersymmetric four dimensional open string models of type IIB string theory compactified on $T^2\times K3$ with Scherk-Schwarz deformation acting on an $S^1$ of the $T^2$ torus. We find that there are always two solutions to the tadpole conditions that are shown to be connected via Wilson lines in an non-trivial way. These models although non

A. Ozpineci S. B. Yakovlev V. S. Zamiralov

New relations between QCD Borel sum rules for masses of Sigma^0 and Lambda hyperons are constructed. It is shown that starting from the sum rule for the Sigma^0 hyperon mass it is straightforward to obtain the corresponding sum rule for the Lambda hyperon mass and vice versa. PACS: 11.30.Hv, 11.55.Hx Keywords: Octet Baryons, Mass sum rules, SU(3)_f Symmetry

A. G. Shuvaev

The solution of DGLAP evolution equation for the twist-3 gluon operators is obtained in the Double Logarithmic Approximation of QCD perturbation theory. The method used for the solution is similar to the reggeon field theory. The asymptotics of the twist-3 parton correlation function for the small Bjorken variables $x_B$ is found.

B. L. Ioffe

In e^+e^- annihilation at \sqrt{s}=10.6 GeV Belle Collaboration found, that J/psi mesons are predominantly produced in association with an extra \bar{c}c pair. The possible mechanisms of J/psi production are discussed and the probability of the associate production of \bar{c}c pair is estimated. The choice between these mechanisms can be done by measuring J/

Ryoichi Yamamoto, Kunimasa Miyazaki, David R. Reichman

We have performed molecular dynamics simulations for a model two-dimensional soft-core mixture in a supercooled state. The mixture exhibits a slow structural relaxation in a quiescent state, however, the relaxation is much enhanced in sheared states. There observed surprisingly small anisotropy both in the coherent and incoherent density correlation function

A. N. Ivanov, M. Cargnelli, M. Faber, J. Marton

We study kaonic hydrogen, the bound K^-p state A_(Kp). Within a quantum field theoretic and relativistic covariant approach we derive the energy level displacement of the ground state of kaonic hydrogen in terms of the amplitude of K^-p scattering for arbitrary relative momenta. The amplitude of low-energy K^-p scattering near threshold is defined by the con

A. A. Kadubovsky, A. V. Klimchuk

By means of color chord diagrams we establish a necessary and sufficient condition for $O$-topological equivalence of functions with one essentially critical point on oriented surfaces with edge. We also calculate the number of $O$-topologically non-equivalent functions with one essentially critical point on oriented surfaces with edge.

B. Blankleider, A. N. Kvinikhidze

In a recent paper by A. Das and X. Zhou [Phys. Rev. D 68, 065017 (2003)] it is claimed that explicit evaluation of the thermal photon self-energy in the Schwinger model gives off-shell thermal Green functions that are different in light-front and conventional quantizations. We show that the claimed difference originates from an erroneous simplification of th

Charles H-T Wang, Smaragda Kessari, Edward R Irvine

By parametrizing the action integral for the standard Schrodinger equation we present a derivation of the recently proposed method for quantizing a parametrized theory. The reformulation suggests a natural extension from conventional to nonlinear quantum mechanics. This generalization enables a unitary description of the quantum evolution for a broad class o

G. Ghirlanda, G. Ghisellini, A. Celotti

We present the results of the spectral analysis of a sample of short bright $γ$--ray bursts (GRB) detected by BATSE and compare them with the average and time resolved spectral properties of long bright bursts. While the spectral parameters of short GRBs confirm, as expected from previous works based on the hardness ratio, that they are harder than long even

William R. B. Lionheart

We review developments, issues and challenges in Electrical Impedance Tomography (EIT), for the 4th Workshop on Biomedical Applications of EIT, Manchester 2003. We focus on the necessity for three dimensional data collection and reconstruction, efficient solution of the forward problem and present and future reconstruction algorithms. We also suggest common

Frank Grossmann

For autonomous systems it is well known how to extract tunneling probabilities from wavepacket calculations. Here we present a corresponding approach for periodically time-dependent Hamiltonians, valid at all frequencies, field strengths, and transition orders. After mapping the periodically driven system onto a time-independent one with an additional degree

Pijush K. Ghosh, Kumar S. Gupta

We study the eigenvalue problem of the rational Calogero model with the coupling of the inverse-square interaction as a complex number. We show that although this model is manifestly non-invariant under the combined parity and time-reversal symmetry ${\cal{PT}}$, the eigenstates corresponding to the zero value of the generalized angular momentum have real en

T. Matsumoto, J. Bec, U. Frisch

Using a very high precision spectral calculation applied to the incompressible and inviscid flow with initial condition $ψ_0(x_1, x_2) = \cos x_1+\cos 2x_2$, we find that the width $δ(t)$ of its analyticity strip follows a $\ln(1/t)$ law at short times over eight decades. The asymptotic equation governing the structure of spatial complex-space singularities

Jounghun Lee

We present a theoretical formalism by which the global and the local mass functions of dark matter substructures (dark subhalos) can be analytically estimated. The global subhalo mass function is defined to give the total number density of dark subhalos in the universe as a function of mass, while the local subhalo mass function counts only those subhalos in