March 2008 arXiv papers — page 20

S. V. Kozyrev

Relation of ultrametric analysis, wavelet theory and cascade models of turbulence is discussed. We construct the explicit solutions for the nonlinear ultrametric integral equation with quadratic nonlinearity. These solutions are built by means of the recurrent hierarchical procedure which is analogous to the procedure used for the cascade models of turbulenc

Kelly Foyle, Stephane Courteau, Robert Thacker

We investigate the evolution of mass density profiles in secular disk galaxy models, paying special attention to the development of a two-component profile from a single initial exponential disk free of cosmological evolution (i.e., no accretion or interactions). As the source of density profile variations, we examine the parameter space of the spin paramete

X. J. Chen, J. L. Wang, V. V. Struzhkin, H. K. Mao

The electronic and lattice dynamical properties of compressed solid SiH$_{4}$ have been calculated in the pressure range up to 300 GPa with density functional theory. We find that structures having a layered network with eight-fold SiH$_{8}$ coordination favor metallization and superconductivity. SiH$_{4}$ in these layered structures is predicted to have sup

Nasser Metwally

In this article, we investigate the purity dynamics of entangled 2 two-level atoms interacting with a single quantized electromagnetic field. We show that the purity of the qubit pairs depends on the initial state of the atomic system. It is found that the superposition case is the best choice to generate entangled states with high purity and hence high enta

C. W. Groth, J. Tworzydlo, C. W. J. Beenakker

By solving a master equation in the Sierpinski lattice and in a planar random-resistor network, we determine the scaling with size L of the shot noise power P due to elastic scattering in a fractal conductor. We find a power-law scaling P ~ L^(d_f-2-alpha), with an exponent depending on the fractal dimension d_f and the anomalous diffusion exponent alpha. Th

Jeremy L Tinker, Andrey V Kravtsov, Anatoly Klypin, Kevork Abazajian

We measure the mass function of dark matter halos in a large set of collisionless cosmological simulations of flat LCDM cosmology and investigate its evolution at z<~2. Halos are identified as isolated density peaks, and their masses are measured within a series of radii enclosing specific overdensities. We argue that these spherical overdensity masses are m

L. Boeri, O. V. Dolgov, A. A. Golubov

In this paper we calculate the electron-phonon coupling of the newly-discovered superconductor LaO$_{1-x}$F$_x$FeAs from first-principles, using Density Functional Perturbation Theory. For pure LaOFeAs, the calculated electron-phonon coupling constant $λ=0.21$ and logarithmic-averaged frequency $ω_{ln}=206 K$, give a maximum $T_c$ of 0.8 K, using the standar

A. J. Bayless, E. L. Robinson, R. I. Hynes, T. A. Ashcraft

The eclipsing low-mass X-ray binary 4U is the prototypical accretion disk corona (ADC) system. We have obtained new time-resolved UV spectrograms of 4U with the Hubble Space Telescope and new V- and J-band light curves with the 1.3-m SMARTS telescope at CTIO. We present an updated ephemeris for the times of the optical/UV eclipses. Model light curves do not

Mireille Bousquet-Mélou

Given an integer partition $\la=(\la_1, ..., \la_\ell)$ and an integer k, denote by $\la^{(k)}$ the sequence of length $\ell$ obtained by reordering the values $|\la_i-k|$ in non-increasing order. If $\la$ dominates $μ$ and has the same weight, then $\la^{(k)}$ dominates $μ^{(k)}$.

Leonardo E. Silbert, Andrea J. Liu, Sidney R. Nagel

Vibrational spectra and normal modes of mechanically stable particle packings in three dimensions are analyzed over a range of compressions, from near the jamming transition, where the packings lose their rigidity, to far above it. At high frequency, the normal modes are localized at all compressions. At low frequency, the nature of the modes depends somewha

C. Fernandes, A. M. Mora, J. J. Merelo, V. Ramos

In this paper we introduce a new ant-based method that takes advantage of the cooperative self-organization of Ant Colony Systems to create a naturally inspired clustering and pattern recognition method. The approach considers each data item as an ant, which moves inside a grid changing the cells it goes through, in a fashion similar to Kohonen&#39;s Self-Or

M. A. Aloy, P. Mimica

Recent theoretical work has pointed out that the transition layer between a jet an the medium surrounding it may be more complex than previously thought. Under physically realizable conditions, the transverse profile of the Lorentz factor in the boundary layer can be non-monotonic, displaying the absolute maximum where the flow is faster than at the jet spin

Atish Dabholkar, Joao Gomes, Sameer Murthy

For dyons in heterotic string theory compactified on a six-torus, with electric charge vector Q and magnetic charge vector P, the positive integer I = g.c.d.(Q \wedge P) is an invariant of the U-duality group. We propose the microscopic theory for computing the spectrum of all dyons for all values of I, generalizing earlier results that exist only for the si

V. Petit, G. A. Wade, L. Drissen, T. Montmerle

The origin of the magnetic fields in neutron stars, and the physical differences between magnetars and strongly magnetised radio pulsars are still under vigorous debate. It has been suggested that the properties of the progenitors of neutron stars (the massive OB stars), such as rotation, magnetic fields and mass, may play an important role in the outcome of

R. I. Raikin, A. A. Lagutin, A. V. Yushkov

Influence of shower fluctuations on the shape of lateral distribution of electrons in EAS of fixed size measured by scintillation counters is analyzed in framework of scaling formalism. Correction factors for the mean square radius of electrons are calculated for the experimental conditions of KASCADE array. Possible improvement of the primary mass discrimin

A. Pizzella, E. M. Corsini, M. Sarzi, J. Magorrian

(abridged) Photometry and long-slit spectroscopy are presented for a sample of 6 galaxies with a low surface brightness stellar disc and a bulge. The stellar and ionised-gas kinematics were measured along the major and minor axis in half of the sample galaxies, whereas the other half was observed only along two diagonal axes. Spectra along two diagonal axes

Sergey Bravyi, David P. DiVincenzo, Daniel Loss, Barbara M. Terhal

We show how to map a given n-qubit target Hamiltonian with bounded-strength k-body interactions onto a simulator Hamiltonian with two-body interactions, such that the ground-state energy of the target and the simulator Hamiltonians are the same up to an extensive error O(epsilon n) for arbitrary small epsilon. The strength of interactions in the simulator Ha

Zdeněk Stuchlík, Stanislav Hledík

Properties of the Reissner-Nordström black-hole and naked-singularity spacetimes with a nonzero cosmological constant are represented by their geodetical structure and embedding diagrams of the central planes of both the ordinary geometry and associated optical reference geometry. Motion of test particles and photons is described in terms of an appropriate `

I. M. Khalatnikov, A. Yu. Kamenshchik

We consider different aspects of the problem of cosmological singularity such as the BKL oscillatory approach to singularity, the new features of the cosmological dynamics in the neighbourhood of the singularity in multidimensional and superstring cosmological models and their connections with such a modern branch of mathematics as infinite-dimensional Lie a

Petr Novotný, Jiří Hrivnák

We consider finite-dimensional complex Lie algebras. We generalize the concept of Lie derivations via certain complex parameters and obtain various Lie and Jordan operator algebras as well as two one-parametric sets of linear operators. Using these parametric sets, we introduce complex functions with fundamental property - invariance under Lie isomorphisms.

Shlomo S. Razamat

We discuss a modification of Gopakumar's prescription for constructing string theory duals of free gauge theories. We use this prescription to construct an unconventional worldsheet dual of the Gaussian matrix model.

Garrit Jentsch, Reiner Kree

The primary activation of the epidermal growth factor receptor (EGFR) has become a prominent target for molecular therapies against several forms of cancer. But despite considerable progress during the last years, many of its aspects remain poorly understood. Experiments on lateral spreading of receptor activity into ligand-free regions challenge the current

Tristan Catelin-Jullien, Costas Kounnas, Herve Partouche, Nicolaos Toumbas

We consider four dimensional heterotic string backgrounds for which supersymmetry is spontaneously broken via the Scherk-Schwarz mechanism on an internal spatial cycle and by finite temperature effects. We concentrate on initially flat backgrounds with N=4 and N=2 amount of supersymmetry. Thermal and quantum corrections give rise to a non-trivial cosmologica

A. Kupść, P. Moskal, M. Zieliński

Multimeson production in pp interactions comprises important background for eta, omega and eta&#39; mesons production experiments and for the studies of their decays planned with WASA detector at COSY. The available information about the reactions is summarized and the need for efforts to describe the processes is stressed.

D. C. Yost, T. R. Schibli, Jun Ye

We demonstrate a novel technique for coupling XUV harmonic radiation out of a femtosecond enhancement cavity. We use a small-period diffraction grating etched directly into the surface of a dielectric mirror. For the fundamental light, this element acts as a high reflector. For harmonic wavelengths, it acts as a diffraction grating, coupling XUV radiation ou

M. L. McClure, Kaem Anderson, Kirk Bardahl

Modifying the Kerr-Schild transformation used to generate black and white hole spacetimes, new dynamic black and white holes are obtained using a time-dependent Kerr-Schild scalar field. Physical solutions are found for black holes that shrink with time and for white holes that expand with time. The black hole spacetimes are physical only in the vicinity of

Giulio Ferrari, Giampaolo Cuoghi

We derive the Schroedinger equation for a spinless charged particle constrained to a curved surface with electric and magnetics fields applied. The particle is confined on the surface using a thin-layer procedure, giving rise to the well-known geometric potential. The electric and magnetic fields are included via the four-potential. We find that there is no

E. M. Beniaminov

A diffusion process for charge distributions in a phase space is examined. The corresponding charge moves in a force field and under an action of a random field. There are the diffusion motions for coordinates and for momenta. In our model, an inner state of the charge is defined by a complex vector. The vector rotates with a great constant angular velocity

Andrzej Derdzinski

This is a brief description of the classical part of the Standard Model of particles and interactions, using the language of vector bundles over the spacetime and operations on them.

John Gibbons, Darryl D Holm, Cesare Tronci

The dynamics of Vlasov kinetic moments is shown to be Lie-Poisson on the dual Lie algebra of symmetric contravariant tensor fields. The corresponding Lie bracket is identified with the symmetric Schouten bracket and the moment Lie algebra is related with a bundle of bosonic Fock spaces, where creation and annihilation operators are used to construct the cold

Margareta Wallquist, Peter Rabl, Mikhail D. Lukin, Peter Zoller

We analyze cavity-assisted cooling schemes for polar molecules in the microwave domain, where molecules are excited on a rotational transition and energy is dissipated via strong interactions with a lossy stripline cavity, as recently proposed by A. Andre et al., Nature Physics 2, 636 (2006). We identify the dominant cooling and heating mechanisms in this se

Jesper Lykke Jacobsen, Hubert Saleur

We consider proper colorings of planar graphs embedded in the annulus, such that vertices on one rim can take Q_s colors, while all remaining vertices can take Q colors. The corresponding chromatic polynomial is related to the partition function of a boundary loop model. Using results for the latter, the phase diagram of the coloring problem (with real Q and

Decai Yu, Elizabeth M. Lupton, Miao Liu, Wei Liu

We investigate the magnetic properties of nano-holes (NHs) patterned in graphene using first principles calculations. We show that superlattices consisting of a periodic array of NHs form a new family of 2D crystalline &#34;bulk&#34; magnets whose collective magnetic behavior is governed by inter-NH spin-spin interaction. They exhibit long-range magnetic ord

C. A. S. Young, R. Zegers

We consider the exchange of identical scalar particles in theories with kappa-deformed Poincare symmetry. We argue that, at least in 1+1 dimensions, the symmetric group S_N can be realized on the space of N-particle states in a kappa-covariant fashion. For the case of two particles this realization is unique: we show that there is only one non-trivial intert

Chr. Bargholtz, M. Bashkanov, M. Berłowski, A. Bondar

The WASA 4pi multidetector system, aimed at investigating light meson production in light ion collisions and eta meson rare decays at the CELSIUS storage ring in Uppsala is presented. A detailed description of the design, together with the anticipated and achieved performance parameters are given.

Shige Peng

We describe a new framework of a sublinear expectation space and the related notions and results of distributions, independence. A new notion of G-distributions is introduced which generalizes our G-normal-distribution in the sense that mean-uncertainty can be also described. W present our new result of central limit theorem under sublinear expectation. This

Paulo Varandas, Marcelo Viana

We prove existence of finitely many ergodic equilibrium states for a large class of non-uniformly expanding local homeomorphisms on compact manifolds and Holder continuous potentials with not very large oscillation. No Markov structure is assumed. If the transformation is topologically mixing there is a unique equilibrium state, it is exact and satisfies a n

U. Munari, A. Henden, M. Valentini, A. Siviero

The moderately fast Nova Oph 2007 reached maximum brightness on March 28, 2007 at V=8.52, B-V=+1.12, V-Rc=+0.76, V-Ic=+1.59 and Rc-Ic=+0.83, after fast initial rise and a pre-maximum halt lasting a week. Decline times were t(V,2)=26.5, t(B,2)=30, t(V,3)=48.5 and t(B,3)=56.5 days. The distance to the nova is d=3.7 kpc, the height above the galactic plane z=21

Vyatcheslav B. Priezzhev, Philippe Ruelle

The correlation functions of an arbitrary number of boundary monomers in the system of close-packed dimers on the square lattice are computed exactly in the scaling limit. The equivalence of the 2n-point correlation functions with those of a complex free fermion is proved, thereby reinforcing the description of the monomer-dimer model by a conformal free fie

E. M. C. Abreu, C. M. L. dos Reis

From the principles of quantum cosmologies we can justify the reason for an inverse-square law for the cosmological constant with no conflict with observations. Although this general expression for $Λ$ is well known in the literature, in this work we introduce some analytical solutions for the scale factor different from the literature. The underlying motiva

Nicolas Mauron

We report new results of our search for rare, cool carbon stars located at large distances from the galactic plane. Eighteen new C stars were discovered. Six are remarkable by showing the two peculiarities of a strong infrared excess at 12 microns and a large height above the Galactic plane, from 1.7 to 6 kpc. The number of C stars with these properties has

Matthias Geissert, Alessandra Lunardi

In this paper we investigate a class of nonautonomous linear parabolic problems with time depending Ornstein-Uhlenbeck operators. We study the asymptotic behavior of the associated evolution operator and evolution semigroup in the periodic and non-periodic situation. Moreover, we show that the associated evolution operator is hypercontractive.

M. H. Montgomery, Kurtis A. Williams, D. E. Winget, Patrick Dufour

We present the results of a search for pulsations in six of the recently discovered carbon-atmosphere white dwarf (&#34;hot DQ&#34;) stars. Based on our theoretical calculations, the star SDSS J142625.71+575218.3 is the only object expected to pulsate. We observe this star to be variable, with significant power at 417.7 s and 208.8 s (first harmonic), making

Richard A Mould

It is claimed in another paper that the collapse of a quantum mechanical wave function is more than invariant, it is trans-representational. It must occur along a fully invariant surface. The obvious surface available for this purpose is that of the backward time cone of the collapse event as proposed by Hellwig and Kraus. This collapse is widely believed to

Alexander E. Kister, James C. Phillips

Protein-protein interactions (protein functionalities) are mediated by water, which compacts individual proteins and promotes close and temporarily stable large-area protein-protein interfaces. In their classic paper Kyte and Doolittle (KD) concluded that the &#34;simplicity and graphic nature of hydrophobicity scales make them very useful tools for the eval

Fiorenza Donato, Nicolao Fornengo, David Maurin

Antideuterons are among the most promising galactic cosmic ray-related targets for dark matter indirect detection. Currently only upper limits exist on the flux, but the development of new experiments, such as GAPS and AMS-02, provides exciting perspectives for a positive measurement in the near future. In this Paper, we present a novel and updated calculati

Camilla Hollanti, Jyrki Lahtonen, Hsiao-feng Francis Lu

We construct explicit rate-one, full-diversity, geometrically dense matrix lattices with large, non-vanishing determinants (NVD) for four transmit antenna multiple-input single-output (MISO) space-time (ST) applications. The constructions are based on the theory of rings of algebraic integers and related subrings of the Hamiltonian quaternions and can be ext

Danilo T. Alves, Edney R. Granhen, Mateus G. Lima

We consider a real massless scalar field in a two-dimensional spacetime, satisfying Dirichlet or Neumann boundary condition at the instantaneous position of a moving boundary. For a relativistic law of motion, we show that Dirichlet and Neumann boundary conditions yield the same radiation force on a moving mirror when the initial field state is invariant und

Tuomas Multamaki, Jani Sainio, Iiro Vilja

The generation of non-gaussianity is studied in a three fluid curvaton model. By utilizing second order perturbation theory we derive general formulae for the large scale temperature fluctuation and non-gaussianity parameter, $f_{NL}$, that includes the possibility of a non-adiabatic final state. In the adiabatic limit we recover previously known results. Th

D. A. Goldston, S. W. Graham, J. Pintz, C. Y. Yildirim

In a previous paper, the authors proved that in any system of three linear forms satisfying obvious necessary local conditions, there are at least two forms that infinitely often assume $E_2$-values; i.e., values that are products of exactly two primes. We use that result to prove that there are inifinitely many integers $x$ that simultaneously satisfy $$ω(x

Baoxiang Wang

We study the Cauchy problem for the generalized elliptic and non-elliptic derivative nonlinear Schrodinger equations, the existence of the scattering operators and the global well posedness of solutions with small data in Besov spaces and in modulation spaces are obtained. In one spatial dimension, we get the sharp well posedness result with small data in cr

Y. S. Kim, Marilyn E. Noz

Since quarks are regarded as the most fundamental particles which constitute hadrons that we observe in the real world, there are many theories about how many of them are needed and what quantum numbers they carry. Another important question is what keeps them inside the hadron, which is known to have space-time extension. Since they are relativistic objects

O. Tiret, F. Combes

The stability of spiral galaxies is compared in modified Newtonian Dynamics (MOND) and Newtonian dynamics with dark matter (DM). We extend our previous simulations that involved pure stellar discs without gas, to deal with the effects of gas dissipation and star formation. We also vary the interpolating function between the MOND and Newtonian regime. Bar for

Uffe Haagerup

In this paper it is proved, that for every prime number p, the set of cyclic p-roots in C^p is finite. Moreover the number of cyclic p-roots counted with multiplicity is equal to (2p-2)!/(p-1)!^2. In particular, the number of complex circulant Hadamard matrices of size p, with diagonal entries equal to 1, is less or equal to (2p-2)!/(p-1)!^2.

F. I. M. Pereira, R. Chan

Self-similar solutions of a collapsing perfect fluid and a massless scalar field with kinematic self-similarity of the first kind in 2+1 dimensions are obtained. Their local and global properties of the solutions are studied. It is found that some of them represent gravitational collapse, in which black holes are always formed, and some may be interpreted as

Victor S. L&#39;vov, Oleksii Rudenko

The letter considers non-isothermal fluid flows and revises simplifications of basic hydrodynamic equations for such flows arriving eventually to a generalization of the Oberbeck-Boussinesq approximation valid for arbitrary equation of state including both non-ideal gases as well as liquids. The proposed approach is based on a suggested general definition of

Robi Peschanski

Using the relation of a set of nonlinear Langevin equations with reaction-diffusion processes, we note the existence of a maximal strength of the noise for the stochastic traveling wave solutions of these equations. Its determination is obtained using the field-theoretical analysis of branching-annihilation random walks near the directed percolation transiti

J. G. Brankov, N. C. Pesheva, N. Zh. Bunzarova

Theoretical advances in the study of non-equilibrium phenomena are briefly reviewed with emphasis on steady state properties of one-dimensional driven lattice gases. The presentation is focused on the totally asymmetric simple-exclusion process (TASEP) with open boundary conditions: particles are injected at the left end with rate alpha and removed at the ri

Aleks Kleyn

Importance of theorem dedicated to isomorphisms consist in statement that they allow to identify different mathematical objects which have something common from the point of view of certain model. This paper considers morphisms of \Ts representation of $\mathfrak{F}$\Hyph algebra and morphisms of \Ts representation of fibered $\mathfrak{F}$\Hyph algebra.

Xuexiang Jin, Yuelong Su, Yi Zhang, Li Li

Modeling of headway/spacing between two consecutive vehicles has many applications in traffic flow theory and transport practice. Most known approaches only study the vehicles running on freeways. In this paper, we propose a model to explain the spacing distribution of queuing vehicles in front of a signalized junction based on random-matrix theory. We show

Paul Fendley, Jesper Lykke Jacobsen

We show how to couple two critical Q-state Potts models to yield a new self-dual critical point. We also present strong evidence of a dense critical phase near this critical point when the Potts models are defined in their completely packed loop representations. In the continuum limit, the new critical point is described by an SU(2) coset conformal field the

Ferenc Iglói, István A. Kovács

We consider random quantum (tight-binding, XX and Ising) spin chains in the off-critical region and study their Griffiths-McCoy singularities. These are obtained from the density of states of the low-energy excitations, which is calculated exactly by the Dyson-Schmidt method. In large finite systems the low-energy excitations are shown to follow the statisti

Etienne Gallais

In the case of smooth manifolds, we use Forman&#39;s discrete Morse theory to realize combinatorially any Thom-Smale complex coming from a smooth Morse function by a couple triangulation-discrete Morse function. As an application, we prove that any Euler structure on a smooth oriented closed 3-manifold has a particular realization by a complete matching on t

Olivier Laval, Sophie Toulouse, Anass Nagih

This article provides an overview of the performance and the theoretical complexity of approximate and exact methods for various versions of the shortest path problem. The proposed study aims to improve the resolution of a more general covering problem within a column generation scheme in which the shortest path problem is the sub-problem.

J. C. Richardson, A. M. N. Ferguson, R. A. Johnson, M. J. Irwin

We present the largest and most detailed survey to date of the stellar populations in the outskirts of M31 based on the analysis of 14 deep HST/ACS pointings spanning the range 11.5-45.0 kpc. We conduct a quantitative comparison of the resolved stellar populations in these fields and identify several striking trends. The color-magnitude diagrams (CMDs), whic

E. V. Deviatov, A. Lorke

This review presents experimental results on the inter-edge-state transport in the quantum Hall effect, mostly obtained in the regime of high imbalance. The application of a special geometry makes it possible to perform I-V spectroscopy between individual edge channels in both the integer and the fractional regime. This makes it possible to study in detail a

Steven Finch, Zai-Qiao Bai, Pascal Sebah

Let f(n) denote the number of odd entries in the nth row of Pascal&#39;s binomial triangle. We study &#34;average dispersion&#34; and &#34;typical dispersion&#34; of f(n) -- the latter involves computing a generalized Lyapunov exponent -- and then turn to numerical analysis of higher dimensional examples.

Marco Spanò, Fabrizio Lillo, Salvatore Miccichè, Rosario N. Mantegna

By performing a comprehensive study on 1832 segments of 1212 complete genomes of viruses, we show that in viral genomes the hairpin structures of thermodynamically predicted RNA secondary structures are more abundant than expected under a simple random null hypothesis. The detected hairpin structures of RNA secondary structures are present both in coding and

S. Van Loo, R. Blomme, S. M. Dougherty, M. C. Runacres

The star Cyg OB2 No. 9 is a well-known non-thermal radio emitter. Recent theoretical work suggests that all such O-stars should be in a binary or a multiple system. However, there is no spectroscopic evidence of a binary component. Re-analysis of radio observations from the VLA of this system over 25 years has revealed that the non-thermal emission varies wi

M. Davidovic, D. Arsenovic, M. Bozic, A. S. Sanz

The momentum distributions associated with both the wave function of a particle behind a grating and the corresponding Bohmian trajectories are investigated and compared. Near the grating, it is observed that the former does not depend on the distance from the grating, while the latter changes with this distance. However, as one moves further apart from the

Paul Buckingham

The Stickelberger elements attached to an abelian extension of number fields conjecturally participate, under certain conditions, in annihilator relations involving higher algebraic K-groups. In [Victor P. Snaith, Stark&#39;s conjecture and new Stickelberger phenomena, Canad. J. Math. 58 (2) (2006) 419--448], Snaith introduces canonical Galois modules hoped

Roman Horsky, Michael Krämer, Alexander Mück, Peter M. Zerwas

The momentum spectrum and the polarization of charginos and neutralinos in squark decays are affected by gluon radiation in the decay process \tilde{q} \to q \tildeχ (g). We determine these corrections and study their impact on the [ql] invariant mass distributions for leptonic \tildeχ decays. The higher-order corrections, though small in general, can be siz

Valery Ilyin, Itamar Procaccia, Ido Regev, Nurith Schupper

We propose that there exists a generic class of glass forming systems that have competing states (of crystalline order or not) which are locally close in energy to the ground state (which is typically unique). Upon cooling, such systems exhibit patches (or clusters) of these competing states which become locally stable in the sense of having a relatively hig

David J. Grynkiewicz

Let $t\geq 1$, let $A$ and $B$ be finite, nonempty subsets of an abelian group $G$, and let $A\pp{i} B$ denote all the elements $c$ with at least $i$ representations of the form $c=a+b$, with $a\in A$ and $b\in B$. For $|A|, |B|\geq t$, we show that either \be\label{almost}\Sum{i=1}{t}|A\pp{i} B|\geq t|A|+t|B|-2t^2+1,\ee or else there exist $A&#39;\subseteq

Victor Bovdi

Let U be the group of units of an infinite twisted group algebra K_λG over a field K. We describe the maximal FC-subgroup of U and give a characterization of U with finitely conjugacy classes. In the case of group algebras we obtain the Cliff-Sehgal-Zassenhaus&#39; theorem.

T. Kahara, K. Tuominen

We study two effective models for QCD, the Nambu-Jona-Lasinio -model and the linear sigma model extended by including a Polyakov loop potential, which is fitted to reproduce pure gauge theory thermodynamics, and a coupling between the chiral fields and the Polyakov loop. Thus the resulting models have as relevant degrees of freedom the Polyakov loop and chir

R. A. Laing, A. H. Bridle, P. Parma, L. Feretti

We present high-quality VLA images of the FR I radio galaxy 3C 31 in the frequency range 1365 to 8440 MHz with angular resolutions from 0.25 to 40 arcsec. Our new images reveal complex, well resolved filamentary substructure in the radio jets and tails. We also use these images to explore the spectral structure of 3C 31 on large and small scales. We infer th

I. V. Drozdov, A. A. Stahlhofen

An interpretation of an electromagnetic quantum as a single pulse is suggested. In this context the Planck formula is shown to be equivalent to the Heisenberg time-energy uncertainty relation. This allows to treat the photon frequency as an inverse time of emission. Such an ansatz avoids the inherent problems of the conventional approach.

N. H. March, A. Cabo, F. Claro, G. G. N. Angilella

In both molecular physics and condensed matter theory, deeper understanding of the correlation energy density epsilon_c (r) remains a high priority. By adopting Loewdin&#39;s definition of correlation energy as the difference between the exact and the Hartree-Fock values, here we propose two alternative routes to define this. One of these involves both exact

Clement Pellegrini

&#34;Quantum trajectories&#34; are solutions of stochastic differential equations also called Belavkin or Stochastic Schrödinger Equations. They describe random phenomena in quantum measurement theory. Two types of such equations are usually considered, one is driven by a one-dimensional Brownian motion and the other is driven by a counting process. In this

H. Arp, C. Fulton

UGC 8584 was selected by a computer program as having a number of quasars around it that obeyed the Karlsson periodicity in its reference frame. On closer examination 9 of the nearest 10 quasars turned out to be extremely close to the predicted values. Also it turned out that UGC 8584 was a disturbed triple galaxy and a strong triple radio source as well as

T. Shirakawa, S. Nishimoto, Y. Ohta

We study the ground-state properties of the double-chain Hubbard model coupled with ferromagnetic exchange interaction by using the weak-coupling theory, density-matrix renormalization group technique, and Lanczos exact-diagonalization method. We determine the ground-state phase diagram in the parameter space of the ferromagnetic exchange interaction and ban

N. Helbig, N. N. Lathiotakis, E. K. U. Gross

We employ reduced density-matrix functional theory in the calculation of the fundamental gap of open-shell systems. The formula for the calculation of the fundamental gap is derived with special attention to the spin of the neutral and the charged systems. We discuss the effects of different functionals as well as the changes due to different basis sets. Als

G. Belanger, O. Kittel, S. Kraml, H. -U. Martyn

We discuss ILC measurements for a specific MSSM scenario with CP phases, where the lightest neutralino is a good candidate for dark matter, annihilating efficiently through t-channel exchange of light staus. These prospective (CP-even) ILC measurements are then used to fit the underlying model parameters. A collider prediction of the relic density of the neu

Victor L&#39;vov, Anna Pomyalov, Itamar Procaccia, Rama Govindarajan

We ask what determines the (small) angle of turbulent jets. To answer this question we first construct a deterministic vortex-street model representing the large scale structure in a self-similar plane turbulent jet. Without adjustable parameters the model reproduces the mean velocity profiles and the transverse positions of the large scale structures, inclu

I. Neri, N. S. Skantzos, D. Bollé

We derive critical noise levels for Gallager codes on asymmetric channels as a function of the input bias and the temperature. Using a statistical mechanics approach we study the space of codewords and the entropy in the various decoding regimes. We further discuss the relation of the convergence of the message passing algorithm with the endogeny property an

K. M. Suzuki, T. Mizushima, M. Ichioka, K. Machida

The core structure of multiply quantized vortices is theoretically investigated in fermionic superfluid near Feshbach resonance. Under population imbalance in two hyperfine spin states, the vortex core is filled in by the ``paramagnetic moment&#39;&#39;. Here, we find the spatial oscillation of the magnetization inside the core sensitively due to the topolog

M. Iihoshi, S. V. Ketov

We consider the purely gravitational fourth-order (in the spacetime curvature) quantum corrections to the Einstein-Hilbert gravity action, coming from superstrings in the leading order with respect to the Regge slope parameter, and study their impact on the evolution of the Hubble scale in the context of the FRW cosmology, in four spacetime dimensions. We pr

E. A. Pechersky, N. D. Vvedenskaya

We consider large fluctuations, namely overload of servers, in a network with dynamic routing of messages. The servers form a circle. The number of input flows is equal to the number of servers, the messages of any flow are distributed between two neighboring servers, upon its arrival a message is directed to the least loaded of these servers. Under the cond

Murat Hudaverdi, Hideyo Kunieda, Takeshi Tanaka, Yoshito Haba

Two nearby clusters of galaxies: A194 (z=0.018) and A1060 (z=0.0114) have been analyzed for their X-ray point source properties with XMM-Newton EPIC-PN data. A multi-band source detection technique was applied to both of the clusters, resulting in 46 sources from the A194 field and 32 sources from the A1060 field, respectively. The cumulative log(N)-log(S) f

Satoshi Fujimoto

We demonstrate that in two-dimensional noncentrosymmetric s-wave superconductors under applied magnetic fields for a particular electron density, topological order emerges, and there exists a zero energy Majorana fermion mode in a vortex core, which obeys non-Abelian statistics, in analogy with p_x+ip_y superconductors, the Moore-Read Pfaffian quantum Hall s

Shu-Kun Lin

Information (I) is defined as the amount of the data after data compression. The first law of information theory: the total amount of data L (the sum of entropy S and information I) of an isolated system remains unchanged. The second law of information theory: Information I of an isolated system decreases to a minimum at equilibrium. The third law of informa

Liane Gabora

Because human cognition is creative and socially situated, knowledge accumulates, diffuses, and gets applied in new contexts, generating cultural analogs of phenomena observed in population genetics such as adaptation and drift. It is therefore commonly thought that elements of culture evolve through natural selection. However, natural selection was proposed

Liane Gabora, Eleanor Rosch, Diederik Aerts

Psychology has had difficulty accounting for the creative, context-sensitive manner in which concepts are used. We believe this stems from the view of concepts as identifiers rather than bridges between mind and world that participate in the generation of meaning. This paper summarizes the history and current status of concepts research, and provides a non-t

Kyle Penner, Maureen van den Berg, JaeSub Hong, Silas Laycock

The Chandra Multiwavelength Plane (ChaMPlane) Survey is a comprehensive effort to constrain the population of accretion-powered and coronal low-luminosity X-ray sources (L_X < 10^33 erg s^-1) in the Galaxy. ChaMPlane incorporates X-ray, optical, and infrared observations of fields in the Galactic Plane imaged with Chandra in the past six years. We present th

K. P. Drumev, C. Bahri, J. P. Draayer, V. G. Gueorguiev

An extended SU(3) shell model that for the first time explicitly includes unique-parity levels is introduced. Shell-model calculations for the isotopes of $^{64}$Ge and $^{68}$Se are performed where valence nucleons beyond the N=28=Z core occupy levels of the normal parity upper-$fp$ shell ($f_{5/2},p_{3/2},p_{1/2}$) and the unique parity $g_{9/2}$ intruder

Takashi Hotta

It is shown that $f$-electron multipole is naturally defined as spin-charge one-electron density operator in the second-quantized form with the use of tensor operator on the analogy of multipole expansion of electromagnetic potential from charge distribution in electromagnetism. Due to this definition of multipole, it is possible to determine multipole state

P. D. Jarvis, L. A. Yates

Representations of the rotation group may be formulated in second-quantised language via Schwinger&#39;s transcription of angular momentum states onto states of an effective two-dimensional oscillator. In the case of the molecular asymmetric rigid rotor, by projecting onto the state space of rigid body rotations, the standard Ray Hamiltonian $H(1,κ,-1)$ (wit

Shengrong Zou

The T helper (Th) phenotypes, Th1/Th2, are acquired upon interaction of a naive T helper cell and an antigen presenting cell (APC). Naive T helper cells may differentiate into either phenotype, and the actual outcome is determined by the density and avidity of the antigenic determinants presented by the APC, and the APCs inherent costimulatory properties. Un

James Bailey, Guozhu Dong, Anthony Widjaja To

We study the problem of deciding satisfiability of first order logic queries over views, our aim being to delimit the boundary between the decidable and the undecidable fragments of this language. Views currently occupy a central place in database research, due to their role in applications such as information integration and data warehousing. Our main resul