March 2009 arXiv papers — page 4

Alexander Mering, Michael Fleischhauer

The ground-state phase diagram of mixtures of spin polarized fermions and bosons in a 1D periodic lattice is discussed in the limit of large fermion hopping and half filling of the fermions. Numerical simulations performed with the density matrix renormalization group (DMRG) show besides bosonic Mott insulating (MI), superfluid (SF), and charge density-wave

Valery A. Liskovets

We investigate properties of a multivariate function $E(m_1,m_2,...,m_r)$, called {\it orbicyclic}, that arises in enumerative combinatorics in counting non-isomorphic maps on orientable surfaces. $E(m_1,m_2,...,m_r)$ proves to be multiplicative, and a simple formula for its calculation is provided. It is shown that the necessary and sufficient conditions fo

Alexander Barvinok, John Hartigan

We describe a maximum entropy approach for computing volumes and counting integer points in polyhedra. To estimate the number of points from a particular set X in R^n in a polyhedron P in R^n, by solving a certain entropy maximization problem, we construct a probability distribution on the set X such that a) the probability mass function is constant on the i

G. Kells, J. K. Slingerland, J. Vala

We present a solution of Kitaev's spin model on the honeycomb lattice and of related topologically ordered spin models. We employ a Jordan-Wigner type fermionization and find that the Hamiltonian takes a BCS type form, allowing the system to be solved by Bogoliubov transformation. Our fermionization does not employ non-physical auxiliary degrees of freed

J. L. Boldo, J. A. Helayel-Neto, L. M. de Moraes, C. A. G. Sasaki

Motivated by the interest raised by the problem of Lorenz-symmetry violating gauge theories in connetion with gravity models, this contribution sets out to provide a general method to systematically study the excitation spectrum of gravity actions which include a Lorentz-symmetry breaking Chern-Simons-type action term for the spin connection. A complete set

Hiroshi Takatsu, Hideki Yoshizawa, Shingo Yonezawa, Yoshiteru Maeno

We report physical properties of the conductive magnet PdCrO2 consisting of a layered structure with a triangular lattice of Cr3+ ions (S=3/2). We confirmed an antiferromagnetic transition at TN=37.5K by means of specific heat, electrical resistivity, magnetic susceptibility, and neutron scattering measurements. The critical behavior in the specific heat per

Zhi-Gang Wang

In this article, we assume that there exists a scalar $D_s^\ast {\bar D}_s^\ast$ molecular state in the $J/ψϕ$ invariant mass distribution, and study its mass using the QCD sum rules. The predictions depend heavily on the two criteria (pole dominance and convergence of the operator product expansion) of the QCD sum rules. The value of the mass is about $M_{D

Charles Francis, Erik Anderson

Context: While CDM models and MOND give explanations for flat rotation curves of other galaxies, both present observational problems and the local gradient of the Milky Way's rotation curve is not flat. Aims: We consider whether flat rotation curves could be an artifact of an unmodelled component in spectral shift. Methods: In the absence of astrometric

William Guerin, Nicolas Mercadier, Davide Brivio, Robin Kaiser

We address the problem of achieving a random laser with a cloud of cold atoms, in which gain and scattering are provided by the same atoms. In this system, the elastic scattering cross-section is related to the complex atomic polarizability. As a consequence, the random laser threshold is expressed as a function of this polarizability, which can be fully det

D. Ebert, R. N. Faustov, V. O. Galkin

Masses of the ground, orbitally and radially excited states of quark-antiquark mesons composed from the light (u,d,s) quarks are calculated within the framework of the relativistic quark model based on the quasipotential approach. The relativistic treatment of the light quark dynamics results in mass spectra which agree well with available experimental data

Lara B. Anderson, James Gray, Andre Lukas, Burt Ovrut

We explicitly describe, in the language of four-dimensional N=1 supersymmetric field theory, what happens when the moduli of a heterotic Calabi-Yau compactification change so as to make the internal non-Abelian gauge fields non-supersymmetric. At the edge of the region in Kahler moduli space where supersymmetry can be preserved, an additional anomalous U(1)

Victor J. W. Guo, Jiang Zeng

Ismail et al. (Constr. Approx. {\bf 15} (1999) 69--81) proved the positivity of some trigonometric polynomials with single binomial coefficients. In this paper, we prove some similar results by replacing the binomial coefficients with products of two binomial coefficients.

Alexey S. Koshelev, Sergey Yu. Vernov

We study cosmological perturbations in models with a single non-local scalar field originating from the string field theory description of the rolling tachyon dynamics. We construct the equation for the energy density perturbations of the non-local scalar field and explicitly prove that for the free field it is identical to a system of local cosmological per

M. van Leeuwen

High-pT particle production is suppressed in heavy ion collisions due to parton energy loss in dense QCD matter. Here we present a systematic comparison of two different theoretical approximations to parton energy loss calculations: the opacity expansion and the multiple-soft scattering approximation for the simple case of a quark traversing a homogeneous pi

Kirill A. Bronnikov, Alexei A. Starobinsky

It is proved that all thin-shell wormholes built from two identical regions of vacuum static, spherically symmetric space-times have a negative shell surface energy density in any scalar-tensor theory of gravity with a non-ghost massless scalar field and a non-ghost graviton.

Ruiming Zhang

In this note, we present a systematic method to explicitly compute the determinants and inverses for some generalized Hilbert matrices associated with orthogonal systems with explicit representations. We expressed the determinant, the inverse and a lower bound for the smallest eigenvalue of such matrix in terms of the explicit orthogonal system.

Matt Kerr, Gregory Pearlstein

We survey recent work on normal functions, including limits and singularities of admissible normal functions, the Griffiths-Green approach to the Hodge conjecture, algebraicity of the zero-locus of a normal function, Neron models, and Mumford-Tate groups. Some of the material and many of the examples, esp. in sec. 5-6, are original. The first two sections sh

Davood Momeni, H. Miraghaei

In this article we present a new exact solution for scalar field with cosmological constant in cylindrical symmetry. Associated cosmological models is discussed. One of them describes a Cyclic universe.

David Witt Nyström

Let $L$ be a big holomorphic line bundle on a complex projective manifold $X.$ We show how to associate a convex function on the Okounkov body of $L$ to any continuous metric $ψ$ on $L.$ We will call this the Chebyshev transform of $ψ,$ denoted by $c[ψ].$ Our main theorem states that the difference of metric volume of $L$ with respect to two metrics, a notio

Massimo Giovannini

Pre-decoupling magnetic fields affect the scalar modes of the geometry and produce observable effects which can be constrained also through the use of current (as opposed to forthcoming) data stemming from the Cosmic Microwave Background observations. The dependence of the temperature and polarization angular power spectra upon the parameters of an ambient m

Lawrence M. Ioannou, Michele Mosca

We demonstrate that the framework of bounded quantum reference frames has application to building quantum-public-key cryptographic protocols and proving their security. Thus, the framework we introduce can be seen as a public-key analogue of the framework of Bartlett et al. (Phys. Rev. A 70, 032307), where a private shared reference frame is shown to have cr

Massimo Campostrini, Ettore Vicari

We study the scaling properties of critical particle systems confined by a potential. Using renormalization-group arguments, we show that their critical behavior can be cast in the form of a trap-size scaling, resembling finite-size scaling theory, with a nontrivial trap critical exponent theta, which describes how the correlation length scales with the trap

Kazuhiro Kuwae, Takashi Shioya

Under an infinitesimal version of the Bishop-Gromov relative volume comparison condition for a measure on an Alexandrov space, we prove a topological splitting theorem of Cheeger-Gromoll type. As a corollary, we prove an isometric splitting theorem for Riemannian manifolds with singularities of nonnegative (Bakry-Emery) Ricci curvature.

Giorgio Ottaviani, Edoardo Sernesi

The hypersurface of Luroth quartic curves inside the projective space of plane quartics has degree 54. We give a proof of this fact along the lines outlined in a paper by Morley, published in 1919. Another proof has been given by Le Potier and Tikhomirov in 2001, in the setting of moduli spaces of vector bundles on the projective plane. Morley's proof us

Arman Shafieloo, Varun Sahni, Alexei A. Starobinsky

We investigate the course of cosmic expansion in its `recent past' using the Constitution SN Ia sample (which includes CfA data at low redshifts), jointly with signatures of baryon acoustic oscillations (BAO) in the galaxy distribution and fluctuations in the cosmic microwave background (CMB). Earlier SN Ia data sets could not address this issue because of a

O. Miettinen, J. Harju, L. K. Haikala, J. Kainulainen

The aims of this study are to determine the properties and spatial distribution of dense cores in Ori B9, and to estimate their ages and dynamical timescales. The cloud was mapped in the 870 micron continuum with APEX/LABOCA, and selected positions were observed in the lines of N2H+ and N2D+ using IRAM-30m. These were used together with our previous H2D+ obs

Benoît Collins, Sho Matsumoto

We give a Fourier-type formula for computing the orthogonal Weingarten formula. The Weingarten calculus was introduced as a systematic method to compute integrals of polynomials with respect to Haar measure over classical groups. Although a Fourier-type formula was known in the unitary case, the orthogonal counterpart was not known. It relies on the Jack pol

Shankar Bhamidi, Remco van der Hofstad, Gerard Hooghiemstra

We study first passage percolation on the configuration model. Assuming that each edge has an independent exponentially distributed edge weight, we derive explicit distributional asymptotics for the minimum weight between two randomly chosen connected vertices in the network, as well as for the number of edges on the least weight path, the so-called hopcount

Silvia Heubach, Sergey Kitaev

A classical result by Guibas and Odlyzko obtained in 1981 gives the generating function for the number of strings that avoid a given set of substrings with the property that no substring is contained in any of the others. In this paper, we give an analogue of this result for the enumeration of compositions that avoid a given set of prohibited substrings, sub

Ioan Bucataru, Matias F. Dahl

Suppose $TM\setminus \{0\}$ and $T\widetilde M\setminus\{0\}$ are slashed tangent bundles of two smooth manifolds $M$ and $\widetilde M$, respectively. In this paper we characterize those diffeomorphisms $F\colon TM\setminus\{0\} \to T\widetilde M\setminus\{0\}$ that can be written as $F = (Dϕ)|_{TM\setminus\{0\}}$ for a diffeomorphism $ϕ\colon M\to \wt M$.

Boyan D. Obreshkov

It is shown that effects of particle identity entail reduction in the number of orbital degrees-of-freedom in non-relativistic 2-particle systems from 6 to 5. This effect of redundancy in description of orbital motion is found to be in correspondence to multiplicative phase factor $(-1)^{2s}$ which accompany interchange of the two particles, where $s$ is the

Hiraku Ogino, Yukari Katsura, Shigeru Horii, Kohji Kishio

We have discovered new layered oxyarsenides (Fe2As2)(Sr4M2O6) (M = Sc, Cr: M-22426). These materials are isostructural with (Fe2P2)(Sr4Sc2O6), which was found in our previous study. The new compounds are tetragonal with a space group of P4/nmm and consist of the anti-fluorite type FeAs layer and perovskite-type blocking layer. The lattice constants are a = 4

Ramakrishna Kakarala

By using properties of the Young orthogonal representation, this paper derives a simple form for the Fourier transform of permutations acting on the homogeneous space of $n$-dimensional vectors, and shows that the transform requires $2n-2$ multiplications and the same number of additions.

Belle Collaboration, B. R. Ko, E. Won

We report the first observation of the doubly Cabibbo-suppressed decay $D^+_s\to K^+K^+π^-$ using 605 fb$^{-1}$ of data collected with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. The branching ratio with respect to its Cabibbo-favored counterpart $\mathcal{B}(D^+_s\to K^+K^+π^-)$ / $\mathcal{B}(D^+_s\to K^+K^-π^+)$ is (0.229$\pm0.028\

Shen Jun, Wu Junde

Sequential effect algebra is an important model for studying quantum measurement theory. In 2005, Professor Gudder presented 25 open problems to motivate its study. The 20th problem asked: In a sequential effect algebra, if the square root of some element exists, is it unique ? We can strengthen the problem as following: For each given positive integer $n>1$

Masato Ito

We present a simple model where anisotropic evolution is driven by kinetic term in extra dimensions. By introducing a canonical or a ghost kinetic term, the possibility of anisotropy is studied.

Yong Yang, Xiao Hu

We studied the pressure effects on the electronic and structural properties of LaOFeAs by first-principles calculations. For the anti-ferromagnetic (AFM) phase with stripe- like aligned Fe spins, the electronic density of states at the Fermi level (N (EF)) slightly descends first with increasing applied pressure, then bounces up with further increasing press

Micah J. Green, A. Nicholas G. Parra-Vasquez, Natnael Behabtu, Matteo Pasquali

The phase behavior of rodlike molecules with polydisperse length and solvent-mediated attraction and repulsion is described by an extension of the Onsager theory for rigid rods. A phenomenological square-well potential is used to model these long-range interactions, and the model is used to compute phase separation and length fractionation as a function of w

J. J. Moyano-Fernández

The aim of this paper is to revise the theory of clusters of infinitely near points for arbitrary fields. We describe in particular the intersection matrix of such a cluster, we introduce the notion of curvette over an arbitrary field and we relate it to the Hamburger-Noether tableaux associated with curves.

Jun Zhang, Marios Kountouris, Jeffrey G. Andrews, Robert W. Heath

This paper proposes an adaptive multi-mode transmission strategy to improve the spectral efficiency achieved in the multiple-input multiple-output (MIMO) broadcast channel with delayed and quantized channel state information. The adaptive strategy adjusts the number of active users, denoted as the transmission mode, to balance transmit array gain, spatial di

J. J. Moyano-Fernández

The aim of this paper is to introduce and investigate the Poincaré series associated with the Weierstraß semigroup of one and two rational points at a (not necessarily irreducible) non-singular projective algebraic curve defined over a finite field, as well as to describe their functional equations in the case of an affine complete intersection.

Andrea Secchi, Massimo Rontani

Few-electron states in carbon-nanotube quantum dots are studied by means of the configuration-interaction method. The peculiar non-interacting feature of the tunneling spectrum for two electrons, recently measured by Kuemmeth et al. [Nature 452, 448 (2008)], is explained by the splitting of a low-lying isospin multiplet due to spin-orbit interaction. Neverth

Ondrej Pejcha

A significant fraction of novae exhibit a series of rebrightenings on the decline branch of their light curves. We use visual observations to study this phase in several well-observed novae. We find that these rebrightenings are isolated flare-like events on otherwise smooth light curves and we show that in most novae in our sample the time intervals between

Leonid I. Manevich, Valeri V. Smirnov

We present an adequate analytical approach to the description of nonlinear vibration with strong energy exchange between weakly coupled oscillators and oscillatory chains. The fundamental notion of the limiting phase trajectory (LPT) corresponding to complete energy exchange is introduced. At first we propose a simple analytical description of vibrations of

S. C. Lim, L. P. Teo

This paper studies the properties of the probability density function $p_{α,ν, n}(\mathbf{x})$ of the $n$-variate generalized Linnik distribution whose characteristic function $φ_{α,ν,n}(\boldsymbol{t})$ is given by φ_{α,ν,n}(\boldsymbol{t})=\frac{1} {(1+\Vert\boldsymbol{t}\Vert^α)^ν}, α\in (0,2], ν>0, \boldsymbol{t}\in \mathbb{R}^n, where $\Vert\boldsymbol{

Marcus Hutter

Given i.i.d. data from an unknown distribution, we consider the problem of predicting future items. An adaptive way to estimate the probability density is to recursively subdivide the domain to an appropriate data-dependent granularity. A Bayesian would assign a data-independent prior probability to "subdivide", which leads to a prior over infinite(ly many)

Rosa M. Torres, Laurent Loinard, Amy J. Mioduszewski, Luis F. Rodriguez

Using multi-epoch Very Long Baseline Array observations, we have measured the trigonometric parallax of the weak-line T Tauri star HP Tau/G2 in Taurus. The best fit yields a distance of 161.2 $\pm$ 0.9 pc, suggesting that the eastern portion of Taurus (where HP Tau/G2 is located) corresponds to the far side of the complex. Previous VLBA observations have sho

Wen-Xiu Ma, Jyh-Hao Lee

A direct approach to exact solutions of nonlinear partial differential equations is proposed, by using rational function transformations. The new method provides a more systematical and convenient handling of the solution process of nonlinear equations, unifying the tanh-function type methods, the homogeneous balance method, the exp-function method, the mapp

P. Bergeron, S. K. Leggett, H. C. Harris

We present a model atmosphere analysis of optical VRI and infrared JHK photometric data of about two dozen ZZ Ceti stars. We first show from a theoretical point of view that the resulting energy distributions are not particularly sensitive to surface gravity or to the assumed convective efficiency, a result which suggests a parameter-free effective temperatu

Jan Michael Rost

Two new forms of strongly coupled plasmas will be discussed. They have become possible to create and observe in the laboratory only recently and exhibit a wealth of intriguing complex behavior which can be studied, in many cases for the first time, experimentally. Plasmas, gases of charged particles, are universal in the sense that certain properties of comp

Rupert L. Frank, Sergey Morozov, Semjon Vugalter

We consider the two-dimensional Pauli operator perturbed by a weakly coupled, attractive potential. We show that besides the eigenvalues arising from the Aharonov-Casher zero modes there are two or one (depending on whether the flux of the magnetic field is integer or not) additional eigenvalues for arbitrarily small coupling and we calculate their asymptoti

Jennifer L. Donovan, Paolo Serra, J. H. van Gorkom, S. C. Trager

ESO 381-47 is an early type galaxy with an extended HI disk. GALEX and very deep optical images reveal a distinct stellar ring far outside the optical body with a diameter of ~30 kpc, which has undergone recent star formation at 1.8 x 10^-4 Msun/yr/kpc^-2, consistent with other new results which detect low level star formation below the traditional Kennicutt

Adam Moss, Douglas Scott

Structure in the Universe grew through gravitational instability from very smooth initial conditions. Energy conservation requires that the growing negative potential energy of these structures is balanced by an increase in kinetic energy. A fraction of this is converted into heat in the collisional gas of the intergalactic medium. Using a toy model of gravi

Philip Kaaret, Stephane Corbel

We obtained optical spectra of the counterpart of the ultraluminous X-ray source NGC 5408 X-1 using the FORS spectrograph on the VLT. The spectra show strong high excitation emission lines, He{\sc ii} $\lambda$4686 and [Ne{\sc V}] $\lambda$3426, indicative of X-ray photoionization. Using the measured X-ray spectrum as input to a photoionization model, we cal

Jacob Abernethy, Alekh Agarwal, Peter L. Bartlett, Alexander Rakhlin

We study the regret of optimal strategies for online convex optimization games. Using von Neumann's minimax theorem, we show that the optimal regret in this adversarial setting is closely related to the behavior of the empirical minimization algorithm in a stochastic process setting: it is equal to the maximum, over joint distributions of the adversary&#

Marko Woelki, Michael Schreckenberg

An asymmetric exclusion process with $N$ particles on $L$ sites is considered where particles can move one or two sites per infinitesimal time-step. An exact analysis for N=2 and a mean-field theory in comparison with simulations show even/odd oscillations in the headway distribution of particles. Oscillations become maximal if particles try to move as far a

Ian Balitsky, Giovanni A. Chirilli

High-energy behavior of amplitudes in a gauge theory can be reformulated in terms of the evolution of Wilson-line operators. In the leading logarithmic approximation it is given by the conformally invariant BK equation for the evolution of color dipoles. In QCD, the next-to-leading order BK equation has both conformal and non-conformal parts, the latter prov

O. L. G. Peres, A. Yu. Smirnov

There are several new features in production, oscillations and detection of the atmospheric neutrinos of low energies, E<100 MeV. The flavor ratio, r, of muon to electron neutrino fluxes is substantially smaller than 2 and decreases with energy, significant part of events is due to the decay of invisible muons at rest, etc. Oscillations in two-layer medium (

Robert J. Scherrer

We examine the time variation of a previously-uninvestigated fundamental dimensionless constant. Constraints are placed on this time variation using historical measurements. A model is presented for the time variation, and it is shown to lead to an accelerated expansion for the universe. Directions for future research are discussed.

A. Vikhlinin, S. Murray, R. Gilli, P. Tozzi

Sensitive, wide-area X-ray surveys which would be possible with the WFXT will detect huge samples of virialized objects spanning the mass range from sub-groups to the most massive clusters, and extending in redshift to beyond z=2. These samples will be an excellent dataset for carrying out many traditional cosmological tests using the cluster mass function a

A. Altomani, C. D. Hill, M. Nacinovich, E. Porten

Let M be a smooth locally embeddable CR manifold, having some CR dimension m and some CR codimension d. We find an improved local geometric condition on M which guarantees, at a point p on M, that germs of CR distributions are smooth functions, and have extensions to germs of holomorphic functions on a full ambient neighborhood of p. Our condition is a form

An. A. Muchnik, Yu. L. Pritykin, A. L. Semenov

The paper is a survey of notions and results related to classical and new generalizations of the notion of a periodic sequence. The topics related to almost periodicity in combinatorics on words, symbolic dynamics, expressibility in logical theories, algorithmic computability, Kolmogorov complexity, number theory, are discussed.

Brandon C. Kelly, Jill Bechtold, Aneta Siemiginowska

We analyze a sample of optical light curves for 100 quasars, 70 of which have black hole mass estimates. Our sample is the largest and broadest used yet for modeling quasar variability. The sources in our sample have z < 2.8 and 10^6 < M_BH < 10^10. We model the light curves as a continuous time stochastic process, providing a natural means of estimating the

Bryant G. Mathews

Let A be a central division algebra over a field F with ind A = n. In computing canonical p-dimension of projective PGL_1(A)-homogeneous varieties, for p prime, we can reduce to the case of generalized Severi-Brauer varieties X_e(A) with ind A a power of p divisible by e. We prove that canonical 2-dimension (and hence canonical dimension) equals dimension fo

E. N. Chikvaidze, T. V. Gogoladze, I. N. Kirikashvili, G. I. Mamniashvili

The stability of albumin-bilirubin complex was investigated depending on pH of solution. It was shown that the stability of complex increases in presence of Mn(II) ions. It was also investigated the paramagnetic composition of gallstones by the electron spin resonance (ESR) method. It turned out that all investigated gallstones contain a free bilirubin radic

Emanuele Berti, Vitor Cardoso, Paolo Pani

The purpose of this short communication is to show that the theory of Breit-Wigner resonances can be used as an efficient numerical tool to compute black hole quasinormal modes. For illustration we focus on the Schwarzschild anti-de Sitter (SAdS) spacetime. The resonance method is better suited to small SAdS black holes than the traditional series expansion

R. Stoll, S. Mathur, Y. Krongold, F. Nicastro

X-ray and UV absorbing outflows are frequently seen in AGN and have been cited as a possible feedback mechanism. Whether or not they can provide adequate feedback depends on how massive they are and how much energy they carry, but it depends in a more fundamental way upon whether they escape the potential of the black hole. If the outflows have reached their

C. Romero, J. B. Formiga, L. F. P. da Silva, F. Dahia

We revisit the Riemann-Cartan geometry in the context of recent higher-dimensional theories of spacetime. After introducing the concept of torsion in a modern geometrical language we present some results that represent extensions of Riemannian theorems. We consider the theory of local embeddings and submanifolds in the context of Riemann-Cartan geometries an

S. Cassel

The Sommerfeld factor for arbitrary partial wave processes is derived in the non-relativistic limit. The s-wave and p-wave numerical results are presented for the case of Yukawa interactions. An approximate analytic expression is also found for the Sommerfeld factor of Yukawa interactions with arbitrary partial waves, which is exact in the Coulomb limit. It

Allan Berele, Bridget Eileen Tenner

In this paper we introduce doubly symmetric functions, arising from the equivalence of particular linear combinations of Schur functions and hook Schur functions. We study algebraic and combinatorial aspects of doubly symmetric functions, in particular as they form a subalgebra of the algebra of symmetric functions. This subalgebra is generated by the odd po

F. William High, Christopher W. Stubbs, Armin Rest, Brian Stalder

We present Stellar Locus Regression (SLR), a method of directly adjusting the instrumental broadband optical colors of stars to bring them into accord with a universal stellar color-color locus, producing accurately calibrated colors for both stars and galaxies. This is achieved without first establishing individual zeropoints for each passband, and can be p

Joerg Jaeckel, Javier Redondo, Andreas Ringwald

Currently, there are a number of light-shining-through-walls experiments searching for hidden photons -- light, sub-eV-scale, abelian gauge bosons beyond the standard model which mix kinetically with the standard photon. We show that in the case that one of these experiments finds evidence for hidden photons, laser communications through matter, using method

P. P. Avelino, D. Bazeia, L. Losano, R. Menezes

This work deals with the dynamics of inflation in the context of a scalar-vector-tensor theory of gravity exhibiting spontaneous Lorentz violation at early times. We describe a first-order formalism which we use to obtain new exact Lorentz violating inflationary solutions for a broad family of models, some in the absence of a potential for the inflaton field

Radu V. Craiu, Antonio Fabio Di Narzo

Recent advances in adaptive Markov chain Monte Carlo (AMCMC) include the need for regional adaptation in situations when the optimal transition kernel is different across different regions of the sample space. Motivated by these findings, we propose a mixture-based approach to determine the partition needed for regional AMCMC. The mixture model is fitted usi

Ulrich Bunke, Matthias Kreck, Thomas Schick

In this paper we give a geometric cobordism description of smooth integral cohomology. This model allows for simple descriptions of both the cup product and the integration, so that it is easy to verify the compatibilty of these structures.

Vincent Rialle, Annick Vila, Yves Besnard

In a certain number of situations, human cognitive functioning is difficult to represent with classical artificial intelligence structures. Such a difficulty arises in the polyneuropathy diagnosis which is based on the spatial distribution, along the nerve fibres, of lesions, together with the synthesis of several partial diagnoses. Faced with this problem w

Yasuhiko Sato

Let $G$ be a countable abelian group. We construct a unital simple projectionless C*-algebra $A$ with a unique tracial state, that satisfies $(K_0(A), [1_A]) \cong (\Z, 1) $, $K_1(A) \cong G$, absorbs the Jiang-Su algebra tensorially, and that is obtained as the inductive limit C*-algebra of a sequence of dimension drop algebras of a specific form. This cons

Oliver Zafiris

Current strategies in system science with a focus on neuroscience do differ in their methodological approach when exploring and trying to analyze a system in order to detect supposed underlying principle processes in its inherent actions, which one might would call rules or laws. The here suggested procedure and measuring device, performs a mapping of charac

Husheng Li

Resource allocation is an important issue in cognitive radio systems. It can be done by carrying out negotiation among secondary users. However, significant overhead may be incurred by the negotiation since the negotiation needs to be done frequently due to the rapid change of primary users&#39; activity. In this paper, a channel selection scheme without neg

T. Peitzmann

Mechanisms proposed to explain the jet-related correlation of long range in rapidity (the ridge) observed in high-energy heavy-ion collisions are reviewed. Limitations of a model using the combined effect of transverse flow and a direction bias of partons suffering energy loss are discussed. The influence of the time scale of the correlation mechanism on the

S. Hoefner

Cool luminous giants, in particular asymptotic giant branch stars, are among the most important sources of cosmic dust. Their extended dynamical atmospheres are places where grains form and initiate outflows driven by radiation pressure, leading to considerable stellar mass loss and the enrichment of the interstellar medium with newly-produced elements. This

D. M. Gitman, I. V. Tyutin, B. L. Voronov

In this paper, we present a mathematically rigorous quantum-mechanical treatment of a one-dimensional motion of a particle in the Calogero potential $αx^{-2}$. Although the problem is quite old and well-studied, we believe that our consideration, based on a uniform approach to constructing a correct quantum-mechanical description for systems with singular po

L. G. Balazs, I. Horvath, Z. Bagoly, A. Meszaros

Using the discriminant analysis of the multivariate statistical analysis we compared the distribution of the physical quantities of the optically dark and bright GRBs, detected by the BAT and XRT on board of the Swift Satellite. We found that the GRBs having detected optical transients (OT) have systematically higher peak fluxes and lower HI column densities

Audrey Moore

Auslander and Ringel-Tachikawa have shown that for an artinian ring R of finite representation type, every R-module is the direct sum of finitely generated indecomposable R-modules. In this paper, we will adapt this result to finite representation type full subcategories of the module category of an artinian ring which are closed under subobjects and direct

S. Murray, R. Gilli, P. Tozzi, M. Paolillo

We discuss the central role played by X-ray studies to reconstruct the past history of formation and evolution of supermassive Black Holes (BHs), and the role they played in shaping the properties of their host galaxies. We shortly review the progress in this field contributed by the current X-ray and multiwavelength surveys. Then, we focus on the outstandin

K. M. Purcell, D. Graf, M. Kano, J. Bourg

We report high-pressure skin depth measurements on the heavy fermion material CeIn3 in magnetic fields up to 64 T using a self-resonant tank circuit based on a tunnel diode oscillator. At ambient pressure, an anomaly in the skin depth is seen at 45 T. The field where this anomaly occurs decreases with applied pressure until approximately 1.0 GPa, where it be

P. Gilkey, S. Nikcevic, U. Simon

We present an algebraic investigation of generalized and equiaffine curvature tensors in a given pseudo-Euclidean vector space and study different orthogonal, irreducible decompositions in analogy to the known decomposition of algebraic curvature tensors. We apply the decomposition results to characterize geometric properties of Codazzi structures and relati

Kazuhiro Tsusaka

It is well known that the electron transfer (ET) reaction in donor-bridge-acceptor systems is much influenced by the bridge conformational changes. However, the importance of the dynamical contribution to the ET rate is still under debate. In this study, we investigate the significance of the dynamical non-Condon effect on the ET rate in the coherent resonan

Marco Pavone, Alessandro Arsie, Emilio Frazzoli, Francesco Bullo

The most widely applied strategy for workload sharing is to equalize the workload assigned to each resource. In mobile multi-agent systems, this principle directly leads to equitable partitioning policies in which (i) the workspace is divided into subregions of equal measure, (ii) there is a bijective correspondence between agents and subregions, and (iii) e

Jinmyung Choi, K. A. Muttalib

We introduce a family of rotationally invariant random matrix ensembles characterized by a parameter $λ$. While $λ=1$ corresponds to well-known critical ensembles, we show that $λ\ne 1$ describes &#34;Lévy like&#34; ensembles, characterized by power law eigenvalue densities. For $λ> 1$ the density is bounded, as in Gaussian ensembles, but $λ<1$ describes ens

Dorje C. Brody, Anna C. T. Gustavsson, Lane P. Hughston

A new framework for deriving equations of motion for constrained quantum systems is introduced, and a procedure for its implementation is outlined. In special cases the framework reduces to a quantum analogue of the Dirac theory of constrains in classical mechanics. Explicit examples involving spin-1/2 particles are worked out in detail: in one example our a

Yaroslav V. Kartashov, Victor A. Vysloukh, Lluis Torner

We consider the propagation of solitons in media with an imprinted transverse periodic or parabolic refractive index modulation when the modulation depth slightly fluctuates along the propagation direction. We find that, under suitable spectral resonance conditions, small transverse soliton oscillations may get parametrically amplified.

Mark M. Wilde

I show how applying a symplectic Gram-Schmidt orthogonalization to the normalizer of a quantum code gives a different way of determining the code&#39;s logical operators. This approach may be more natural in the setting where we produce a quantum code from classical codes because the generator matrices of the classical codes form the normalizer of the result

Eric Archambault, David Campbell, Yves Gingras, Vincent Lariviere

For more than 40 years, the Institute for Scientific Information (ISI, now part of Thomson Reuters) produced the only available bibliographic databases from which bibliometricians could compile large-scale bibliometric indicators. ISI&#39;s citation indexes, now regrouped under the Web of Science (WoS), were the major sources of bibliometric data until 2004,

Z. P. Wang, P. M. Dinh, P. -G. Reinhard, E. Suraud

Applying time-dependent local density approximation (TDLDA), we study the high-order harmonic generation (HHG) of ethylene subjected to the one-color ($ω=2.72$ eV) and the two-color ($ω_1=2.72$ eV and $ω_2=5.44$ eV) ultrashort intense laser pulses. The HHG spectrum of ethylene in the one-color laser field shows the obvious plateaus and odd order harmonics ar

Mike Gillard, Paul Sutcliffe

We study configurations of intersecting domain walls in a Wess-Zumino model with three vacua. We introduce a volume-preserving flow and show that its static solutions are configurations of intersecting domain walls that form double bubbles, that is, minimal area surfaces which enclose and separate two prescribed volumes. To illustrate this field theory appro

Richard P. Boland, Tobias Galla, Alan J. McKane

We study the effects of intrinsic noise on chemical reaction systems, which in the deterministic limit approach a limit cycle in an oscillatory manner. Previous studies of systems with an oscillatory approach to a fixed point have shown that the noise can transform the oscillatory decay into sustained coherent oscillations with a large amplitude. We show tha

Z. P. Wang, P. M. Dinh, P. -G. Reinhard, E. Suraud

Using time-dependent density functional theory, applied to valence electrons, coupled non-adiabatically to molecular dynamics of the ions, we study the induced dynamics of ethylene subjected to the laser field. We demonstrate the reliable quality of such an approach in comparison to the experimental data on atomic and molecular properties. The impact of ioni

Luis A. Zapata, Johannes Schmid-Burgk, Dirk Muders, Peter Schilke

We present CO(2-1), $^{13}$CO(2-1), CO(6-5), CO(7-6), and SO(6$_5-5_4$) line observations made with the {\it IRAM 30 m} and {\it APEX} radiotelescopes and the {\it Submillimeter Array} toward the highly collimated and extended southwest lobe of the bipolar outflow {\it Ori-S6} located in the Orion South region. We report, for all these lines, the detection o

Z. P. Wang, P. M. Dinh, P. -G. Reinhard, E. Suraud

The influences of water molecules surrounding biological molecules during irradiation with heavy particles (atoms,ions) are currently a major subject in radiation science on a molecular level. In order to elucidate the underlying complex reaction mechanisms we have initiated a joint experimental and theoretical investigation with the aim to make direct compa