December 2008 arXiv papers — page 4

Dongho Chae

In this paper we prove that under some integrability conditions for the density and the velocity fields the only stationary weak solutions to the compressible fluid equations on $\Bbb R^N$ correspond to the zero density. In the case of compressible magnetohydrodynamics equations similar integrability conditions for density, velocity and the magnetic fields l

Haim Diamant

This article gives an overview of recent theoretical and experimental findings concerning the hydrodynamic interaction between liquid-embedded particles in various confined geometries. A simple unifying description emerges, which accounts for the various findings based on the effect of confinement on conserved fields of the embedding liquid. It shows, in par

Ivan P. Levkivskyi, Alexey Boyarsky, Juerg Froehlich, Eugene V. Sukhorukov

We propose direct experimental tests of the effective models of fractional quantum Hall edge states. We first recall a classification of effective models based on the requirement of anomaly cancellation and illustrate the general classification with the example of a quantum Hall fluid at filling factor 2/3. We show that, in this example, it is impossible to

Rebecca Goldin, Megumi Harada, Tara S. Holm, Takashi Kimura

In their 2007 paper, Jarvis, Kaufmann, and Kimura defined the full orbifold $K$-theory of an orbifold ${\mathfrak X}$, analogous to the Chen-Ruan orbifold cohomology of ${\mathfrak X}$ in that it uses the obstruction bundle as a quantum correction to the multiplicative structure. We give an explicit algorithm for the computation of this orbifold invariant in

John C. Baez, Aristide Baratin, Laurent Freidel, Derek K. Wise

A "2-group" is a category equipped with a multiplication satisfying laws like those of a group. Just as groups have representations on vector spaces, 2-groups have representations on "2-vector spaces", which are categories analogous to vector spaces. Unfortunately, Lie 2-groups typically have few representations on the finite-dimensional 2-ve

Samik Datta, Gustav W. Delius, Richard Law

This paper investigates the dynamics of biomass in a marine ecosystem. A stochastic process is defined in which organisms undergo jumps in body size as they catch and eat smaller organisms. Using a systematic expansion of the master equation, we derive a deterministic equation for the macroscopic dynamics, which we call the deterministic jump-growth equation

Marcus Spradlin, Anastasia Volovich, Congkao Wen

Arkani-Hamed et. al. have recently shown that all tree-level scattering amplitudes in maximal supergravity exhibit exceptionally soft behavior when two supermomenta are taken to infinity in a particular complex direction, and that this behavior implies new non-trivial relations amongst amplitudes in addition to the well-known on-shell recursion relations. We

Thomas B. Schrøder, Ulf R. Pedersen, Nicholas Bailey, Søren Toxværd

Results from molecular dynamics simulations of two viscous molecular model liquids -- the Lewis-Wahnstrom model of ortho-terphenyl and an asymmetric dumbbell model -- are reported. We demonstrate that the liquids have a ``hidden'' approximate scale invariance: Equilibrium potential energy fluctuations are accurately described by inverse power law (IP

J. Fransson, O. Eriksson, A. V. Balatsky

We provide a theory for scanning tunneling microscopy and spectroscopy using a spin-polarized tip. It it shown that the tunneling conductance can be partitioned into three separate contributions, a background conductance which is independent of the local spin, a dynamical conductance which is proportional to the local spin moment, and a conductance which is

Alina Beygelzimer, Sanjoy Dasgupta, John Langford

We present a practical and statistically consistent scheme for actively learning binary classifiers under general loss functions. Our algorithm uses importance weighting to correct sampling bias, and by controlling the variance, we are able to give rigorous label complexity bounds for the learning process. Experiments on passively labeled data show that this

Fedor L. Bezrukov, Amaury Magnin, Mikhail Shaposhnikov

We analyse one-loop radiative corrections to the inflationary potential in the theory, where inflation is driven by the Standard Model Higgs field. We show that inflation is possible provided the Higgs mass m_H lies in the interval m_min<m_H<m_max, where m_min=[136.7+(m_t-171.2)*1.95]GeV, m_max=[184.5+(m_t-171.2)*0.5]GeV and m_t is the mass of the top quark.

Jiri Podolsky, Ondrej Prikryl

We study pure radiation spacetimes of algebraic types O and N with a possible cosmological constant. In particular, we present explicit transformations which put these metrics, that were recently re-derived by Edgar, Vickers and Machado Ramos, into a general Ozsvath-Robinson-Rozga form. By putting all such metrics into the unified coordinate system we confir

Shahn Majid

Whereas the classical sphere $C P^1$ can be defined as the coordinate algebra generated by the matrix entries of a projector $e$ with $\trace(e)=1$, the fuzzy-sphere is defined in the same way by $\trace(e)=1+λ$. We show that the standard $q$-sphere is similarly defined by $\trace_q(e)=1$ and the Podles 2-spheres by $\trace_q(e)=1+λ$, thereby giving a unifie

Mohammed Abouzaid

In dimensions congruent to 1 modulo 4, we prove that the cotangent bundle of an exotic sphere which does not bound a parallelisable manifold is not symplectomorphic to the cotangent bundle of the standard sphere. More precisely, we prove that such an exotic sphere cannot embed as a Lagrangian in the cotangent bundle of the standard sphere. The main ingredien

Peter Trifonov

A novel algorithm is proposed for the interpolation step of the Guruswami-Sudan list decoding algorithm. The proposed method is based on the binary exponentiation algorithm, and can be considered as an extension of the Lee-O&#39;Sullivan algorithm. The algorithm is shown to achieve both asymptotical and practical performance gain compared to the case of iter

Y. Wiaux, L. Jacques, G. Puy, A. M. M. Scaife

Radio interferometry probes astrophysical signals through incomplete and noisy Fourier measurements. The theory of compressed sensing demonstrates that such measurements may actually suffice for accurate reconstruction of sparse or compressible signals. We propose new generic imaging techniques based on convex optimization for global minimization problems de

S. L. Lyakhovich, A. A. Sharapov

A systematic procedure is proposed for deriving all the gauge symmetries of the general, not necessarily variational, equations of motion. For the variational equations, this procedure reduces to the Dirac-Bergmann algorithm for the constrained Hamiltonian systems with certain extension: it remains applicable beyond the scope of Dirac&#39;s conjecture. Even

R. Chan, M. F. A. da Silva, P. Rocha, Anzhong Wang

Dynamical models of prototype gravastars made of phantom energy are constructed, in which an infinitely thin spherical shell of a perfect fluid with the equation of state $p = (1-γ)σ$ divides the whole spacetime into two regions, the internal region filled with a dark energy (or phantom) fluid, and the external Schwarzschild region. It is found that in some

Peter K. F. Kuhfittig

One way to explain the present acceleration of the Universe is Einstein&#39;s cosmological constant. It is quite likely, in view of some recent studies, that a time-dependent equation of state had caused the Universe to evolve from an earlier phantom-energy model. In that case traversable wormholes could have formed spontaneously. It is shown in this paper t

Budnytska Tetiana

A map $f: \ff^n \to \ff^n$ over a field $\ff$ is called affine if it is of the form $f(x)=Ax+b$, where the matrix $A \in \ff^{n\times n}$ is called the linear part of affine map and $b \in \ff^n$. The affine maps over $\ff=\rr$ or $\cc$ are investigated. We prove that affine maps having fixed points are topologically conjugate if and only if their linear par

Roger Bielawski, Victor Pidstrygach

We study the complex symplectic structure of the quiver varieties corresponding to the moduli spaces of SU(2) instantons on both commutative and non-commutative R^4. We identify global Darboux coordinates and quadratic Hamiltonians on classical phase spaces for which these quiver varieties are natural completions. We also show that the group of non-commutati

Ilkka Kylänpää, Tapio T. Rantala

Path integral Monte Carlo simulation of the dipositronium &#34;molecule&#34; Ps$_2$ reveals its surprising thermal instability. Although, the binding energy is $\sim 0.4$ eV, due to the strong temperature dependence of its free energy Ps$_2$ dissociates, or does not form, above $\sim 1000$ K, except for high densities where a small fraction of molecules are

A. V. Stoyanovsky

We state analogs of the binomial theorem and the exponential function for variables $x$, $y$ commuting as $yx=qxy$.

Y. G. Shi, S. Yu, A. A. Belik, Y. Matsushita

A wide-range doping was achieved by a high-pressure method for TbFeAsO1-x from &#34;under doped&#34; to &#34;over doped&#34; superconducting compositions throughout the optimized superconductivity (Tc of 44 K). Tc vs. lattice constant shows a dome-shaped feature, while Tc vs. the lattice constant likely follows a unique empirical curve over the doping range.

Gyula Lakos

The $H$-ring structure of certain infinite(-dimensional) Grassmannians is discussed using various algebraic and analytical methods but so that cellular arguments are avoided. These methods allow us to discuss these Grassmannian in greater generality.

Jure Leskovec, Deepayan Chakrabarti, Jon Kleinberg, Christos Faloutsos

How can we model networks with a mathematically tractable model that allows for rigorous analysis of network properties? Networks exhibit a long list of surprising properties: heavy tails for the degree distribution; small diameters; and densification and shrinking diameters over time. Most present network models either fail to match several of the above pro

Daniele Fargion, Paola Di Giacomo

To foresee a solar flare neutrino signal we infer its upper and lower bound. The upper bound was derived since a few years by general energy equipartition arguments on observed solar particle flare. The lower bound, the most compelling one for any guarantee neutrino signal, is derived by most recent records of hard Gamma bump due to solar flare on January 20

Frédéric Jugeau

It is known, since the 70&#39;s, that the large N &#39;t Hooft limit of gauge theories is related to string theories. In 1998, J. M. Maldacena identified precisely such a relation: the so-called AdS/CFT correspondence which speculates a duality between a large N strongly-coupled supersymmetric and conformal Yang-Mills theory in four dimensions and a weakly-c

Paul Kersten, Iosif Krasil'shchik, Alexander Verbovetsky, Raffaele Vitolo

We prove that the Kupershmidt deformation of a bi-Hamiltonian system is itself bi-Hamiltonian. Moreover, Magri hierarchies of the initial system give rise to Magri hierarchies of Kupershmidt deformations as well. Since Kupershmidt deformations are not written in evolution form, we start with an outline a geometric framework to study Hamiltonian properties of

Luis Silvestre

We prove that weak solutions of a slightly supercritical quasi-geostrophic equation become smooth for large time. We prove it using a De Giorgi type argument using ideas from a recent paper by Caffarelli and Vasseur.

Paul Kersten, Iosif Krasil&#39;shchik, Alexander Verbovetsky, Raffaele Vitolo

We sketch out a new geometric framework to construct Hamiltonian operators for generic, non-evolutionary partial differential equations. Examples on how the formalism works are provided for the KdV equation, Camassa-Holm equation, and Kupershmidt&#39;s deformation of a bi-Hamiltonian system.

Oleg N. German, Nikolay G. Moshchevitin

We prove a result on the existence of linear forms of a given Diophantine type.

Kouji Nakamura

Along the general framework of the gauge-invariant perturbation theory developed in the papers [K. Nakamura, Prog. Theor. Phys. {\bf 110} (2003), 723; {\it ibid}, {\bf 113} (2005), 481.], we re-derive the second-order Einstein equations on four-dimensional homogeneous isotropic background universe in gauge-invariant manner without ignoring any mode of pertur

D. Zaborov

A new calibration technique using natural background light of sea water has been recently developed for the ANTARES experiment. The method relies on correlated coincidences produced in triplets of optical modules by Cherenkov light of beta-particles originated from Potassium-40 decays. A simple but powerful approach to atmospheric muon flux studies is curren

Ts. Tsogbayar

The static dipole polarizabibility for the $1sσ$ electron state of the $\mathrm{H}_{2}^{+}$ hydrogen molecular ion is calculated within Born-Oppenheimer approximation. The variational expansion with randomly chosen exponents has been used for numerical studies. The results obtained for the dipole polarizability are accurate to the nine digits.

Andrei M. Beloborodov

Magnetospheres of neutron stars are anchored in the rigid crust and can be twisted by sudden crustal motions (&#34;starquakes&#34;). The twisted magnetosphere does not remain static and gradually untwists, dissipating magnetic energy and producing radiation. The equation describing this evolution is derived, and its solutions are presented. Two distinct regi

Francesca Sammarruca, Pei Liu

We explore neutron skin predictions for $^{208}$Pb in relation to the symmetry pressure in various microscopic models based on realistic nucleon-nucleon potentials and either the Dirac-Brueckner-Hartree-Fock approach or the conventional Brueckner-Hartree-Fock framework implemented with three-body forces. We also discuss the correlation between the neutron sk

Marcin Kubasik, Marco Koschorreck, Mario Napolitano, Sebastián R. de Echaniz

We describe the implementation of a system for studying light-matter interactions using an ensemble of $10^6$ cold rubidium 87 atoms, trapped in a single-beam optical dipole trap. In this configuration the elongated shape of the atomic cloud increases the strength of the collective light-atom coupling. Trapping all-optically allows for long storage times in

Zhenghua Xu, Chunhui Lai

For given a graph $H$, a graphic sequence $π=(d_1,d_2,...,d_n)$ is said to be potentially $H$-graphic if there exists a realization of $π$ containing $H$ as a subgraph. In this paper, we characterize the potentially $K_6-C_5$ -graphic sequences.

Larry McLerran

I provide a brief introduction to the theoretical ideas and phenomenological motivation for the Color Glass Condensate and the Glasma

John R. Klein, William Richter

Let K be a connected finite complex. This paper studies the problem of whether one can attach a cell to some iterated suspension S^j K so that the resulting space satisfies Poincare duality. When this is possible, we say that S^j K is a spine. We introduce the notion of quadratic self duality and show that if K is quadratically self dual, then S^j K is a spi

Jakub Javorský, Martin Setvín, Ivan Ošt&#39;ádal, Pavel Sobotík

Growth of atomic indium chains - 1D islands - on the Si(100)-2x1 surface was observed by scanning tunneling microscopy (STM) at room temperature and simulated by means of a kinetic Monte Carlo method. Density of indium islands and island size distribution were obtained for various deposition rates and coverage. STM observation of growth during deposition of

Albrecht Schmidt

This is a proposal of an algebra which aims at distributed array processing. The focus lies on re-arranging and distributing array data, which may be multi-dimensional. The context of the work is scientific processing; thus, the core science operations are assumed to be taken care of in external libraries or languages. A main design driver is the desire to c

G. Chung, S. Sridharan, S. Vishwanath, C. S. Hwang

This paper considers the problem of cognitive radios with partial-message information. Here, an interference channel setting is considered where one transmitter (the &#34;cognitive&#34; one) knows the message of the other (&#34;legitimate&#34; user) partially. An outer bound on the capacity region of this channel is found for the &#34;weak&#34; interference

Piotr Biler, Grzegorz Karch

The existence and nonexistence of global in time solutions is studied for a class of equations generalizing the chemotaxis model of Keller and Segel. These equations involve Lévy diffusion operators and general potential type nonlinear terms.

Mu-Chun Chen, K. T. Mahanthappa

We review recent developments in theoretical models for neutrino masses and mixing. Emphases are given to models based on finite group family symmetries. In particular, we describe one recent model based on SU(5), in which both the tri-bimaximal neutrino mixing and realistic CKM matrix are generated. We also discuss two models based on a non-anomalous U(1)_F

K. K. Gan

We study the feasibility of fabricating an optical link for the SLHC ATLAS silicon tracker based on the current pixel optical link architecture. The electrical signals between the current pixel modules and the optical modules are transmitted via micro-twisted cables. The optical signals between the optical modules and the data acquisition system are transmit

Piotr Biler, Grzegorz Karch, Regis Monneau

We study a nonlinear pseudodifferential equation describing the dynamics of dislocations. The long time asymptotics of solutions is described by the self-similar profiles.

Ahmad Fino, Grzegorz Karch

The large time behavior of nonnegative solutions to the reaction-diffusion equation $\partial_t u=-(-Δ)^{α/2}u - u^p,$ $(α\in(0,2], p>1)$ posed on $\mathbb{R}^N$ and supplemented with an integrable initial condition is studied. We show that the anomalous diffusion term determines the large time asymptotics for $p>1+α/{N},$ while nonlinear effects win if $p\l

Joshua Erlich

AdS/QCD is an extra-dimensional approach to modeling the light hadronic resonances in QCD. AdS/QCD models are generally successful at reproducing low-energy observables with around 10-20% accuracy, depending on the details of the model. We discuss the motivation for these models, their intrinsic limitations, and some recent results.

Cecilia Knoll, Charles Fulton

In this paper we give simplified formulas for certain polynomials which arise in some new Titchmarsh-Weyl m-functions for the radial part of the separated Hydrogen atom on the half line and two independent programs for generating them using the symbolic manipulator Mathematica.

Neil G. Dickson

The problem of space-optimal jump encoding in the x86 instruction set, also known as branch displacement optimization, is described, and a linear-time algorithm is given that uses no complicated data structures, no recursion, and no randomization. The only assumption is that there are no array declarations whose size depends on the negative of the size of a

Andrew R. Kustin, Bernd Ulrich

We first describe a situation in which every graded Betti number in the tail of the resolution of $\frac RJ$ may be read from the socle degrees of $\frac RJ$. Then we apply the above result to the ideals $J$ and $J^{[q]}$; and thereby describe a situation in which the graded Betti numbers in the tail of the resolution of $R/J^{[q]}$ are equal to the graded B

N. A. Carella

This note discusses the existence of prime numbers in short intervals. An unconditional elementary argument seems to prove the existence of primes in the short intervals [x, x + y], where y >= x^(1/2)(log x)^e, e > 0, and a sufficiently large number x > 0. Further, an extension of Bertrand&#39;s postulate to arithmetic progressions will be considered

Andrew R. Kustin, Claudia Polini, Bernd Ulrich

Consider a height two ideal, $I$, which is minimally generated by $m$ homogeneous forms of degree $d$ in the polynomial ring $R=k[x,y]$. Suppose that one column in the homogeneous presenting matrix $\f$ of $I$ has entries of degree $n$ and all of the other entries of $\f$ are linear. We identify an explicit generating set for the ideal $\Cal A$ which defines

Dragos Oprea

We determine the splitting type of the Verlinde vector bundles in higher genus in terms of simple semihomogeneous factors. In agreement with strange duality, the simple factors are interchanged by the Fourier-Mukai transform, and their spaces of sections are naturally dual.

Philip W Anderson

The observations of non-linear rotational susceptibility (NCRI) in samples of solid He below 1-200 mK temperatures are conjectured to be describable in terms of a rarified Gross-Pitaevskii superfluid of vacancies (or, more generally, incommensuracies) with a transition temperature of about 50 mK, whose density is locally enhanced by crystal imperfections. We

D. F. Jackson Kimball, Khoa Nguyen, K. Ravi, Arijit Sharma

Alkali vapor cells with antirelaxation coating (especially paraffin-coated cells) have been a central tool in optical pumping and atomic spectroscopy experiments for 50 years. We have discovered a dramatic change of the alkali vapor density in a paraffin-coated cell upon application of an electric field to the cell. A systematic experimental characterization

Andrei V. Pakoulev, Vladimir Burtman, Dmitry Zaslavsky

When redox active molecules are covalently tethered to the surface of the n-doped silicon, light induces their oxidation by the semiconductor. To visualize this charge separation we have followed the formation and decay of the surface photovoltage by an auxiliary transparent electrode, which serves as a capacitive probe that picks up the transient surface ph

G. Malescio, F. Saija, S. Prestipino

We show that a system of particles interacting through the exp-6 pair potential, commonly used to describe effective interatomic forces under high compression, exhibits anomalous melting features such as reentrant melting and a rich solid polymorphism, including a stable BC8 crystal. We relate this behavior to the crossover, with increasing pressure, between

H. T. Quan, H. Dong

We consider the quantum mechanical generalization of Crooks Fluctuation Theorem and Jarzynski Equality for an open quantum system. The explicit expression for microscopic work for an arbitrary prescribed protocol is obtained, and the relation between quantum Crooks Fluctuation Theorem, quantum Jarzynski Equality and their classical counterparts are clarified

Farkhad G. Aliev, Juan F. Sierra, Ahmad A. Awad, Gleb N. Kakazei

We report on linear spin dynamics in the vortex state of the Permalloy dots subjected to stratified (magnetic) field. We demonstrate experimentally and by simulations the existence of two distinct dynamic regimes corresponding to the vortex stable and metastable states. Breaking cylindrical symmetry leads to unexpected eigenmodes frequency splitting in the s

J. F. Sierra, V. V. Pryadun, F. G. Aliev, S. E. Russek

Ferromagnetic resonance and static magnetic properties of CoFe/Al2O3/CoFe/Py and CoFe/Al2O3/CoFeB/Py magnetic tunnel junctions and of 25nm thick single-layer Permalloy(Py) films have been studied as a function of temperature down to 2K. The temperature dependence of the ferromagnetic resonance excited in the Py layers in magnetic tunnel junctions shows knee-

D. Batcheldor, G. Schneider, D. C. Hines, G. D. Schmidt

The findings of a nine orbit calibration plan carried out during HST Cycle 15, to fully determine the NICMOS camera 2 (2.0 micron) polarization calibration to high accuracy, are reported. Recently Ueta et al. and Batcheldor et al. have suggested that NICMOS possesses a residual instrumental polarization at a level of 1.2-1.5%. This would completely inhibit t

Alexander Dainiak

We obtain sharp lower and upper bounds for the number of maximal (under inclusion) independent sets in trees with fixed number of vertices and diameter. All extremal trees are described up to isomorphism.

Kohei Motegi, Kazumitsu Sakai

The exact expression for the density matrix of the kink ground state of the ferromagnetic XXZ chain is obtained. Utilizing this, we exactly calculate various correlation functions such as the longitudinal and transverse spin-spin correlation functions, and the ferromagnetic and antiferromagnetic string formation probabilities. The asymptotic behaviors of the

S. Massaglia

We present the general properties of the Active Galactic Nuclei (AGNs) and discuss the origin and structure of jets that are associated to a fraction of these objects. We then we address the problems of particle acceleration at highly relativistic energies and set limits on the luminosity of AGN jets for being origin of UHECRs.

A. Yu. Illarionov, B. A. Kniehl, A. V. Kotikov

We study the heavy-quark contributions to the proton structure functions $F_2^i(x,Q^2)$ and $F_L^i(x,Q^2)$, with $i=c,b$, for small values of Bjorken&#39;s $x$ variable and provide compact formulas for their ratios $R_i=F_L^i/F_2^i$ that are useful to extract $F_2^i(x,Q^2)$ from measurements of the doubly differential cross section of inclusive deep-inelasti

Antony Valentini

It is argued that the natural kinematics of the pilot-wave theory is Aristotelian. Despite appearances, Galilean invariance is not a fundamental symmetry of the low-energy theory. Instead, it is a fictitious symmetry that has been artificially imposed. It is concluded that the search for a Lorentz-invariant extension is physically misguided.

V. O. Esin, A. S. Krivonosova, I. Zh. Sattybaev, L. V. Elokhina

X-ray structural and spectral analyses, X-ray diffraction topography and metallography were used to study dendrite structure of Al-4 wt % Cu single crystals grown by the Bridgman technique at a rate of 1 mm/min and on seeds with <001> orientation. The single crystals were obtained upon the crystallization of the melt under the action of a pressure and the gr

M. Klein, Y. Xiao, M. Hohensee, D. F. Phillips

We report a preliminary experimental study of EIT and stored light in the high optical depth regime. In particular, we characterize two ways to mitigate radiation trapping, a decoherence mechanism at high atomic density: nitrogen as buffer gas, and a long, narrow cell geometry. Initial results show the promise of both approaches in minimizing radiation trapp

Anh-Minh Tang, Yu-Jun Cui, Javad Eslami, Pauline Défossez

The soil compaction by vehicles is a major factor responsible for physical degradation of cultivated soils. Uniaxial confined compression tests are usually performed to characterise the compaction properties of soil. Two main forms of compression curve have been observed: (i) the bi-linear curve having an elastic rebound curve at low stresses and a linear vi

Pradip Das, C. V. Tomy, H. Takeya, S. Ramakrishnan

We present magnetic field dependence of the critical current density from dc-magnetization measurements concerning the anisotropic behavior of flux line lattice (FLL) in a single crystal of YNi_2B_2C. The peak effect (PE) phenomenon is observed for all crystallographic orientations, but the second magnetization peak (SMP) anomaly is observed only for H//a. O

Wojciech Broniowski, Wojciech Florkowski, Mikolaj Chojnacki, Adam Kisiel

It is shown how the initial azimuthally asymmetric flow develops from the free-streaming + sudden equilibration approximation to the early dynamics in relativistic heavy-ion collisions. Consequences for the hydrodynamics and physical results are discussed.

Michael Courtney, Amy Courtney

Reconstruction of shooting events occasionally requires testing of bullets at velocities significantly below the typical muzzle velocity of cartridge arms. Trajectory, drag, and terminal performance depend strongly on velocity, and realistic results require accurately reconstructing the velocity. A method is presented for testing bullets at reduced velocitie

Amy Courtney, Michael Courtney

An attempt to redefine science in the 21st century (BK Jennings, On the Nature of Science, Physics in Canada, 63(7) 2007) has abandoned traditional notions of natural law and objective reality, blurred the distinctions between natural science and natural history, elevated Occam&#39;s razor from an epistemological preference to a scientific principle, and ele

A. Bostan, S. Boukraa, S. Hassani, J. -M. Maillard

We recall various multiple integrals related to the isotropic square Ising model, and corresponding, respectively, to the n-particle contributions of the magnetic susceptibility, to the (lattice) form factors, to the two-point correlation functions and to their lambda-extensions. These integrals are holonomic and even G-functions: they satisfy Fuchsian linea

Michael Courtney, Amy Courtney

In response to a published assertion to the contrary, this paper briefly reviews many studies that document remote wounding effects of ballistic pressure waves including experiments in pigs and dogs that find brain injury resulting from animal models shot in the thigh and case studies in humans that document both remote brain and spinal cord injuries ascribe

Tian-Jun Li

In this paper we show that every degree 2 homology class of a 2n-dimensional symplectic manifold is represented by an immersed symplectic surface if it has positive symplectic area. Moreover, the symplectic surface can be chosen to be embedded if 2n is at least 6. We also analyze the additional conditions under which embedded symplectic representatives exist

Jiri Podolsky, Martin Zofka

We investigate a general metric of the Kundt class of spacetimes in higher dimensions. Geometrically, it admits a non-twisting, non-shearing and non-expanding geodesic null congruence. We calculate all components of the curvature and Ricci tensors, without assuming any specific matter content, and discuss algebraic types and main geometric constraints impose

Michael Courtney, Amy Courtney

An article (J Trauma 29:10-18, 1989) cites unpublished wound ballistics data to support the authors&#39; view that distant injuries are a myth in wound ballistics. The actual data, published in 1990, actually contains a number of detailed examples of distant injuries. (Bellamy RF, Zajtchuk R. The physics and biophysics of wound ballistics. In: Zajtchuk R, ed

O F Oxtoby, I V Barashenkov

The method of multiple scales is used to study the wobbling kink of the $ϕ^4$ equation. The amplitude of the wobbling is shown to decay very slowly, as $t^{-1/2}$, and hence the wobbler turns out to be an extremely long-lived object.

Rainer Beck

Radio synchrotron emission, its polarization and its Faraday rotation are powerful tools to study the strength and structure of interstellar magnetic fields. The total intensity traces the strength and distribution of total magnetic fields. Total fields in gas-rich spiral arms and bars of nearby galaxies have strengths of 20-30 $μ$Gauss, due to the amplifica

G. Pignata, J. Maza, M. Hamuy, R. Antezana

The CHASE project started in 2007 with the aim of providing young southern supernovae (SNe) to the Carnegie Supernova Project (CSP) and Millennium Center for Supernova Studies (MCSS) follow-up programs. So far CHASE has discovered 33 SNe with an average of more than 2.5 SNe per month in 2008. In addition to the search we are carrying out a follow-up program

N. V. Gribova, Yu. D. Fomin, Daan Frenkel, V. N. Ryzhov

We report a computer-simulation study of the equilibrium phase diagram of a three-dimensional system of particles with a repulsive step potential. The phase diagram is obtained using free-energy calculations. At low temperatures, we observe a number of distinct crystal phases. We show that at certain values of the potential parameters the system exhibits the

Amir Daneshgar, Roozbeh Ebrahimi Soorchaei

In this paper, based on the contributions of Tucker (1983) and Seb{ő} (1992), we generalize the concept of a sequential coloring of a graph to a framework in which the algorithm may use a coloring rule-base obtained from suitable forcing structures. In this regard, we introduce the {\it weak} and {\it strong sequential defining numbers} for such colorings an

Dániel Marx, Ildikó Schlotter

In the k-Apex problem the task is to find at most k vertices whose deletion makes the given graph planar. The graphs for which there exists a solution form a minor closed class of graphs, hence by the deep results of Robertson and Seymour, there is an O(n^3) time algorithm for every fixed value of k. However, the proof is extremely complicated and the consta

A. Yu. Illarionov, A. V. Kotikov

In the leading twist approximation of the Wilson operator product expansion with standard and &#34;frozen&#34; versions of strong copling constant we show that the Bessel-inspired behavior of the structure function $F_2$ at small $x$, obtained for a flat initial condition in the DGLAP evolution, leads to very good agreement with the deep inelastic scattering

Li Tang, Zeqian Chen, Zeng-Bing Chen

In this paper, we show that there are eight distinct forms of the Greenberger-Horne-Zeilinger (GHZ) argument for the four-qubit cluster state $|\phi_4>$ and forty eight distinct forms for the five-qubit cluster state $|\phi_5>$ in the case of the one-dimensional lattice. The proof is obtained by regarding the pair qubits as a single object and constructing t

A. V. Stoyanovsky

We derive some, seemingly new, curious additive relations in the Pascal triangle. They arise in summing up the numbers in the triangle along some vertical line up to some place.

Andreas Henrici, Thomas Kappeler

The periodic Toda lattice with $N$ sites is globally symplectomorphic to a two parameter family of $N-1$ coupled harmonic oscillators. The action variables fill out the whole positive quadrant of $\R^{N-1}$. We prove that in the interior of the positive quadrant as well as in a neighborhood of the origin, the Toda Hamiltonian is strictly convex and therefore

Hatem Widyan

Scalar field theory with an asymmetric potential is studied at zero temperature and high-temperature for $ϕ^6$ potential. The equations of motion are solved numerically to obtain O(4) spherical symmetric and O(3) cylindrical symmetric bounce solutions. These solutions control the rates for tunneling from the false vacuum to the true vacuum by bubble formatio

Sergio del Campo, Ramon Herrera

Brane inflationary universe model in the context of intermediate inflation is studied. General conditions for this model to be realizable are discussed. In the high-energy limit we describe in great details the characteristic of this model.

Hatem Widyan

The temperature dependance of the action in the thin-wall and thick-wall limits is obtained analytically for the $ϕ^6$ scalar potential. The nature of the phase transition is investigated from the quantum tunnelling regime at low temperatures to the thermal hopping regime at high temperatures. It is first-order for the case of a thin wall while for the thick

Alexander Burinskii

Kerr-Schild (KS) geometry of the rotating black-holes and spinning particles is based on the associated with Kerr theorem twistor structure which is defined by an analytic curve $F(Z)=0$ in the projective twistor space $Z \in CP^3 .$ On the other hand, there is a complex Newman representation which describes the source of Kerr-Newman solution as a &#34;parti

X H Meng, X Dou

The universe content is considered as a non-perfect fluid with bulk viscosity and can be described by a general equation of state (endowed some deviation from the conventionally assumed cosmic perfect fluid model). An explicitly bulk viscosity dark energy model is proposed to confront consistently with the current observational data sets by statistical analy

Chiyori Urabe, Shinji Takesue

Fracture in a disordered lattice system is studied. In our system, particles are initially arranged on the triangular lattice and each nearest-neighbor pair is connected with a randomly chosen soft or hard Hookean spring. Every spring has the common threshold of stress at which it is cut. We make an initial crack and expand the system perpendicularly to the

Zhenglu Jiang, Leonid Ossipkov

A method is presented for finding anisotropic distribution functions for stellar systems with known, spherically symmetric, densities, which depends only on the two classical integrals of the energy and the magnitude of the angular momentum. It requires the density to be expressed as a sum of products of functions of the potential and of the radial coordinat

Alberto De Sole, Victor Kac

We find an interpretation of the complex of variational calculus in terms of the Lie conformal algebra cohomology theory. This leads to a better understanding of both theories. In particular, we give an explicit construction of the Lie conformal algebra cohomology complex, and endow it with a structure of a g-complex. On the other hand, we give an explicit c

B. Olmos, R. González-Férez, I. Lesanovsky

We study the excitation dynamics of Rydberg atoms in a one-dimensional lattice with periodic boundary conditions where the atomic Rydberg states are resonantly excited from the electronic ground state. Our description of the corresponding dynamics is numerically exact within the perfect blockade regime, i.e. no two atoms in a given range can be excited. The