January 2009 arXiv papers — page 25

Michel Habib, Vincent Limouzy

We present here some results on particular elimination schemes for chordal graphs, namely we show that for any chordal graph we can construct in linear time a simplicial elimination scheme starting with a pending maximal clique attached via a minimal separator maximal (resp. minimal) under inclusion among all minimal separators.

Mohammad A. Ganjali

By placing a collection of membranes in 11 dimensional background supergravity six form field and considering the non-linear action of multiple membranes we obtain the potential for transverse scalar fields of membranes and study some possible vacuum configurations. We find that the system has a stable vacuum in which is a formation of membranes into fuzzy t

U. Schilling, C. Thiel, E. Solano, T. Bastin

Incoherent scattering of photons off two remote atoms with a Lambda-level structure is used as a basic Young-type interferometer to herald long-lived entanglement of an arbitrary degree. The degree of entanglement, as measured by the concurrence, is found to be tunable by two easily accessible experimental parameters. Fixing one of them to certain values unv

A. Orefice

The Maxwell integral equations expressing Ampere's and Faraday's laws are shown to be affected by heavy physical approximations. The usual deduction from them, moreover, of the corresponding set of differential Maxwell equations is based, in general, on a wrong use of the Stokes theorem. The equivalence, therefore, between the two sets of equations m

Ezequiel Alvarez, Francisco D. Mazzitelli

We consider the interaction of two perfectly conducting plates of arbitrary shape that are inside a non-simply connected cylinder with transverse section of the same shape. We show that the existence of transverse electromagnetic (TEM) modes produces a Casimir force that decays only as $1/a^2$, where $a$ is the distance between plates. The TEM force does not

Radoslaw Szmytkowski

Coefficients in the expansions of the form $\partial P_{n}(λ;z)}/\partialλ=\sum_{k=0}^{n}a_{nk}(λ)P_{k}(λ;z)$, where $P_{n}(λ;z)$ is the $n$th classical (the generalized Laguerre, Gegenbauer or Jacobi) orthogonal polynomial of variable $z$ and $λ$ is a parameter, are evaluated. A method we adopt in the present paper differs from that used by Fröhlich [Integr

Michael Barnes

To faithfully simulate ITER and other modern fusion devices, one must resolve electron and ion fluctuation scales in a five-dimensional phase space and time. Simultaneously, one must account for the interaction of this turbulence with the slow evolution of the large-scale plasma profiles. Because of the enormous range of scales involved and the high dimensio

Xing-Gang Wu, Tao Huang

Based on the approach of the vector form factor $F^{+}_{B\toπ, K}(q^2)$ in our previous papers, we extend the calculation of the radiative corrections to the $B\to P$ ($P$ stands $π$, $K$ and all light pseudoscalar mesons) scalar and tensor form factors $F^{0,T}_{B\to P}(q^2)$ with chiral current in the light-cone sum rules (LCSRs). The most uncertain twist-

Pan Zhang, Ying Zeng, Haijun Zhou

The vertex-cover problem is a prototypical hard combinatorial optimization problem. It was studied in recent years by physicists using the cavity method of statistical mechanics. In this paper, the stability of the finite-temperature replica-symmetric (RS) and the first-step replica-symmetry-broken (1RSB) cavity solutions of the vertex cover problem on rando

Mariusz Puchalski, Krzysztof Pachucki

Accurate calculations of the fine and hyperfine splitting of the 2P state in Li and Be$^+$ isotopes using the explicitly correlated Hylleraas basis set are presented. Theoretical predictions including the mixing of $P_{1/2}$ and $P_{3/2}$ states, relativistic and quantum electrodynamics effects on hyperfine interactions, are compared with experimental values

Benjamin A. Burton

The enumeration of normal surfaces is a crucial but very slow operation in algorithmic 3-manifold topology. At the heart of this operation is a polytope vertex enumeration in a high-dimensional space (standard coordinates). Tollefson's Q-theory speeds up this operation by using a much smaller space (quadrilateral coordinates), at the cost of a reduced so

Florian Hebenstreit, Reinhard Alkofer, Gerald V. Dunne, Holger Gies

We investigate electron-positron pair production from vacuum for short laser pulses with sub-cycle structure, in the nonperturbative regime (Schwinger pair production). We use the non-equilibrium quantum kinetic approach, and show that the momentum spectrum of the created electron-positron pairs is extremely sensitive to the sub-cycle dynamics -- depending o

Seok-Chan Youn, Hyun-Woo Lee, H. -S. Sim

We theoretically study electron interference in a ballistic electronic interferometer capacitively coupled to a quantum dot. The visibility of the interference is reduced when the dot has degenerate ground states with different excess charges. The degree of the reduction depends on system parameters such as the strength of the capacitive coupling, and the de

Michał Kukieła

We generalise some results of R. E. Stong concerning finite spaces to wider subclasses of Alexandroff spaces. These include theorems on function spaces, cores and homotopy type. In particular, we characterize pairs of spaces X,Y such that the compact-open topology on C(X,Y) is Alexandroff, introduce the classes of finite-paths and bounded-paths spaces and sh

Toshiki Maruyama, Satoshi Chiba, Hans-Josef Schulze, Toshitaka Tatsumi

We investigate the property of the hadron-quark mixed phase using the Brueckner-Hartree-Fock model for hadron (hyperon) phase and the MIT bag model for quark phase. To satisfy the Gibbs conditions, charge density as well as baryon number density becomes non-uniform in the mixed phase, accompanying phase separation. We clarify the roles of the surface tension

Eylee Jung, DaeKil Park, Jin-Woo Son

Some mixed states composed of only GHZ states can be expressed in terms of only W-states. This fact implies that such states have vanishing three-tangle. One of such rank-3 states, $Π_{GHZ}$, is explicitly presented in this paper. These results are used to compute analytically the three-tangle of a rank-4 mixed state $σ$ composed of four GHZ states. This ana

Lars Andersson

I will discuss some recent results on marginally outer trapped surfaces, apparent horizons, and the trapped region. A couple of applications of the results developed for marginally outer trapped surfaces to coalescence of black holes and to the characterization of the trapped region are given.

Shao-Wen Wei, Ran Li, Yu-Xiao Liu, Ji-Rong Ren

Considering gravitational and gauge anomalies at the horizon, a new method that to derive Hawking radiations from black holes has been developed by Wilczek et al. In this paper, we apply this method to non-rotating and rotating Kaluza-Klein black holes with squashed horizon, respectively. For the rotating case, we found that, after the dimensional reduction,

Mingxing Luo, Sibo Zheng

Supersymmetric models with extended group structure beyond the standard model are revisited in the framework of general gauge mediation. Sum rules for sfermion masses are shown to depend genuinely on the group structure, which can serve as important probes for specific models. The left-right model and models with extra U(1) are worked out for illustrations.

Zhaohu Nie

For a manifold with boundary, the restriction of Chern's transgression form of the Euler curvature form over the boundary is closed. Its cohomology class is called the secondary Chern-Euler class and used by Sha to formulate a relative Poincaré-Hopf theorem, under the condition that the metric on the manifold is locally product near the boundary. We show

Vitaly Bergelson, Terence Tao, Tamar Ziegler

Let $\F$ a finite field. We show that the universal characteristic factor for the Gowers-Host-Kra uniformity seminorm $U^k(\X)$ for an ergodic action $(T_g)_{g \in \F^ω}$ of the infinite abelian group $\F^ω$ on a probability space $X = (X,\B,μ)$ is generated by phase polynomials $ϕ: X \to S^1$ of degree less than $C(k)$ on $X$, where $C(k)$ depends only on $

Yasumichi Aoki

Renormalization conditions imposed on quark bilinear vertex functions in the conventional RI/MOM scheme use exceptional momentum configurations. With practical values for the lattice cutoff, these vertex functions are contaminated with unwanted low energy physics (pion pole, zero modes, etc), which is a large source of systematic error. These effects can be

J. Fresnais, J. -F. Berret, B. Frka-Petesic, O. Sandre

A paradigm proposed recently by Boal et al. (A.K. Boal et al., Nature 404, 746-748, 2000) deals with the possibility to use inorganic nanoparticles as building blocks for the design and fabrication of colloidal and supracolloidal assemblies. It is anticipated that these constructs could be made of different shapes, patterns and functionalities and could cons

A. Imparato, L. Peliti

We consider the relation between the microscopic and effective descriptions of the unfolding experiment on a model polypeptide. We evaluate the probability distribution function of the performed work by Monte Carlo simulations and compare it with that obtained by evaluating the work distribution generating function on an effective Brownian motion model tailo

Eric Polizzi

A new numerical algorithm for solving the symmetric eigenvalue problem is presented. The technique deviates fundamentally from the traditional Krylov subspace iteration based techniques (Arnoldi and Lanczos algorithms) or other Davidson-Jacobi techniques, and takes its inspiration from the contour integration and density matrix representation in quantum mech

Teresa Montaruli

The South Pole is an optimal location for hosting astrophysical observatories. The status of the construction of the IceCube Observatory and some selected physics results will be discussed. Moreover prospects for detection of Ultra-High Energy cosmogenic neutrinos and techniques that can address this energy region will be considered.

A. Deltuva

The method of screening and renormalization for including the Coulomb interaction in the framework of momentum-space integral equations is applied to the three- and four-body nuclear reactions. The Coulomb effect on the observables and the ability of the present nuclear potential models to describe the experimental data is discussed.

Teresa Montaruli

I will discuss the motivations for Neutrino Astronomy and its prospects given the current experimental scenario, which is the main focus of this paper. I will also go through the first results of the IceCube detector deep in the ice and of the ANTARES undersea telescope underlying complementary aspects, common and different challenges. It is an exciting time

Ben Fairbairn, Jürgen Müller

We provide involutory symmetric generating sets of finitely generated Coxeter groups, fulfilling a suitable finiteness condition, which in particular is fulfilled in the finite, affine and compact hyperbolic cases.

N. Crokidakis

The effects of locally random magnetic fields are considered in a nonequilibrium Ising model defined on a square lattice with nearest-neighbors interactions. In order to generate the random magnetic fields, we have considered random variables $\{h\}$ that change randomly with time according to a double-gaussian probability distribution, which consists of two

Maciej Ulas

Let $f(z)=z^5+az^3+bz^2+cz+d \in \Z[z]$ and let us consider a del Pezzo surface of degree one given by the equation $\cal{E}_{f}: x^2-y^3-f(z)=0$. In this note we prove that if the set of rational points on the curve $E_{a, b}:Y^2=X^3+135(2a-15)X-1350(5a+2b-26)$ is infinite, then the set of rational points on the surface $\cal{E}_{f}$ is dense in the Zariski

G. G. N. Angilella, N. H. March, F. M. D. Pellegrino, R. Pucci

Starting from relativistic quantum field theories, Kovtun et al. (2005) have quite recently proposed a lower bound eta/s >= hbar /(4 pi kB), where eta is the shear viscosity and s the volume density of entropy for dense liquids. If their proposal can eventually be proved, then this would provide key theoretical underpinning to earlier semiempirical proposals

Christopher M. Graney

The Copernican Principle (which says the Earth and sun are not unique) should have observational consequences and thus be testable. Galileo Galilei thought he could measure the true angular diameters of stars with his telescope; according to him, stars visible to the naked eye range in diameter from a fraction of a second to several seconds of arc. He used t

Milan Janjic

It is shown in this note that non-central Stirling numbers s(n,k,a) of the first kind naturally appear in the expansion of derivatives of the product of a power function and a logarithn function. We first obtain a recurrence relation for these numbers, and then, using Leibnitz rule we obtain an explicit formula for these numbers. We also obtain an explicit f

V. Mishra, G. Boyd, S. Graser, T. Maier

We show, using a simple model, how ordinary disorder can gap an extended-$s$ ($A_{1g}$) symmetry superconducting state with nodes. The concommitant crossover of thermodynamic properties, particularly the $T$-dependence of the superfluid density, from pure power law behavior to an activated one is exhibited. We discuss applications of this scenario to experim

Marton Naszodi

Let $H_d$ denote the smallest integer $n$ such that for every convex body $K$ in $\Re^d$ there is a $0<λ< 1$ such that $K$ is covered by $n$ translates of $λK$. In the book \emph{Research problems in discrete geometry.} by Brass, Moser and Pach, the following problem was posed: Is there a $0<λ_d<1$ depending on $d$ only with the property that every convex bo

Wei Chen, Dao N. H. Nam, Jiwei Lu, Kevin G. West

Magnetic tunnel junctions (MTJ) with AlOx barrier were fabricated by a deposition tool called Biased Target Ion Beam Deposition (BTIBD) using low energy ion source (0-50 eV) and voltage biased targets. The BTIBD system applies bias voltage directly and only on the desired targets, providing enough sputtering energy and avoiding &#34;overspill&#34; contaminat

Vahid Karimipour, Zohreh Meghdadi, Laleh Memarzadeh

We investigate the question of optimal input ensembles for memory channels and construct a rather large class of Pauli channels with correlated noise which can be studied analytically with regard to the entanglement of their optimal input ensembles. In a more detailed study of a subclass of these channels, the complete phase diagram of the two-qubit channel,

Paolo Maraner, Jiannis K. Pachos

The equations describing the Kaluza-Klein reduction of conformally flat spaces are investigated in arbitrary dimensions. Special classes of solution related to pseudo-Kahler and para-Kahler structures are constructed and classified according to spacetime dimension, signature and gauge field rank. Remarkably, rank two solutions include gravitational kinks tog

Apisit Pakapongpun, Thomas Ward

We study the functorial and growth properties of closed orbits for maps. By viewing an arbitrary sequence as the orbit-counting function for a map, iterates and Cartesian products of maps define new transformations between integer sequences. An orbit monoid is associated to any integer sequence, giving a dynamical interpretation of the Euler transform.

Sergei Maslov, S. Redner

We review our recent work on applying the Google PageRank algorithm to find scientific &#34;gems&#34; among all Physical Review publications, and its extension to CiteRank, to find currently popular research directions. These metrics provide a meaningful extension to traditionally-used importance measures, such as the number of citations and journal impact f

M. Axenides, E. G. Floratos, S. Nicolis

We propose a quantization of linear, volume preserving, maps on the discrete and finite 3-torus T_N^3 represented by elements of the group SL(3,Z_N). These flows can be considered as special motions of the Nambu dynamics (linear Nambu flows) in the three dimensional toroidal phase space and are characterized by invariant vectors, a, of T_N^3. We quantize all

J. Gracia, N. Vlahakis, I. Agudo, K. Tsinganos

We present self-consistent global, steady-state MHD models and synthetic optically thin synchrotron emission maps for the jet of M87. The model consist of two distinct zones: an inner relativistic outflow, which we identify with the observed jet, and an outer cold disk-wind. While the former does not self-collimate efficiently due to its high effective inert

D. J. Kusterer, T. Nagel, K. Werner

AM CVn systems are interacting binaries similar to cataclysmic variables (CVs), but more compact with orbital periods of less than 80 minutes. The primary is a white dwarf, whereas the nature of the secondary is not completely clear, yet. Abundances and composition of the outer layer of the secondary can be found by analysis of the accretion disk (presented

G. Naumenko, X. Artru, A. Potylitsyn, Yu. Popov

In coherent radiation sources (diffraction radiation, Smith-Purcell effect, etc.) based on relativistic electrons passing by a material radiator, the electron self-field is partly shadowed after each part of the radiator over a distance of the order of the formation length g2l. This effect has been investigated on coherent diffraction radiation (DR) by elect

O. G. Balev, F. T. Vasko, V. Ryzhii

Heating of carriers in an intrinsic graphene under dc electric field is considered taking into account the intraband energy relaxation due to acoustic phonon scattering and the interband generation-recombination transitions due to thermal radiation. The distribution of nonequilibrium carriers is obtained for the cases when the intercarrier scattering is unes

Kai-He Ding, Zhen-Gang Zhu, Jamal Berakdar

We present a theoretical study on the spin-dependent transport through a spin valve consisting of graphene sandwiched between two magnetic leads with an arbitrary orientation of the lead magnetization. No gate voltage is applied. Using Keldysh&#39;s nonequilibrium Green&#39;s function method we show that, in absence of external magnetic fields, the current-v

Jaeuk U. Kim, W. -R. Lee, Hyun-Woo Lee, H. -S. Sim

We study the spatial decay of electron coherence due to electron-electron interaction in a finite-length disorder-free quantum wire. Based on the Luttinger liquid theory, we demonstrate that the coherence length characterizing the exponential decay of the coherence can vary from region to region, and that the coherence can even revive after the decay. This c

I. Cahit

The chromatic number of an planar graph is not greater than four and this is known by the famous four color theorem and is equal to two when the planar graph is bipartite. When the planar graph is even-triangulated or all cycles are greater than three we know by the Heawood and the Grotszch theorems that the chromatic number is three. There are many conjectu

A. K. Kazansky, P. M. Echenique

One-dimensional model for study of sub--femtosecond experiment with metal surface is put forward. The important features of the system, such as the pseudopotential for electron motion in the metal bulk, abrupt decrease of the normal to the surface external electromagnetic field in the bulk, finite value of the mean free path for electrons in the metal, and a

Jian-Zu Zhang

An induced fractional zero-point angular momentum of charged particles by the Bohm-Aharonov (B-A) vector potential is realized via a modified combined trap. It explores a &#34;spectator&#34; mechanism in this type of quantum effects: In the limit of the kinetic energy approaching one of its eigenvalues the B-A vector potential alone cannot induce a fractiona

Ana Y. Rodriguez Marrero, Diego F. Torres, Elsa de Cea Del Pozo

We present a theoretical model that explains the high energy phenomenology of the neighborhood of SNR IC 443, as observed with the Major Atmospheric Gamma Imaging Cherenkov (MAGIC) telescope and the Energetic Gamma-Ray Experiment Telescope (EGRET). We also discuss how the model can be tested with observations by the Fermi Gamma-ray Large Area Space Telescope

Gérard Henry Edmond Duchamp, H. Cheballah

We point out four problems which have arisen during the recent research in the domain of Combinatorial Physics.

Yeong Gyun Kim, Seodong Shin

It has been suggested that, considering channeling effect, the order of a few GeV dark matters which are elastically scattered from detector nuclei might be plausible candidates reconciling the DAMA annual modulation signal with the results of other null experiments. We show that Singlet Fermionic Dark Matter can be such a dark matter candidate, simultaneous

Jian-Zu Zhang, Ke-Lin Gao, Chuan-Gang Ning

The possibility of testing spatial noncommutativity by current experiments on normal quantum scales is investigated. For the case of both position-position and momentum-momentum noncommuting spectra of ions in crossed electric and magnetic fields are studied in the formalism of noncommutative quantum mechanics. In a limit of the kinetic energy approaching it

Hongyun Li, J. Chen, Hongbing Jiang, Jie Liu

Nonsequential double ionization (NSDI) of helium in an intense few-cycle laser pulse is investigated by applying the three-dimensional semi-classical re-scattering method. It is found that the momentum distribution of He$^{2+}$ shows a single-double-single peak structure as the pulse intensity increases. According to the different mechanisms dominating the N

Yong Peng, Dinesh Rajan

In this paper, we investigate the half-duplex cooperative communication scheme of a two user Gaussian interference channel. We develop achievable region and outer bound for the case when the system allow either transmitter or receiver cooperation. We show that by using our transmitter cooperation scheme, there is significant capacity improvement compare to t

Grant M. Kennedy, Scott J. Kenyon

We use published optical spectral and IR excess data from nine young clusters and associations to study the stellar mass dependent dispersal of circumstellar disks. All clusters older than ~3 Myr show a decrease in disk fraction with increasing stellar mass for Solar to higher mass stars. This result is significant at about the 1 $σ$ level in each cluster. F

Hirotachi Abo, Giorgio Ottaviani, Chris Peterson

Let $Gr(k,n)$ be the Plücker embedding of the Grassmann variety of projective $k$-planes in $¶n$. For a projective variety $X$, let $σ_s(X)$ denote the variety of its $s-1$ secant planes. More precisely, $σ_s(X)$ denotes the Zariski closure of the union of linear spans of $s$-tuples of points lying on $X$. We exhibit two functions $s_0(n)\le s_1(n)$ such tha

Massimiliano Esposito, Katja Lindenberg, Christian Van den Broeck

We investigate the efficiency of power generation by thermo-chemical engines. For strong coupling between the particle and heat flows and in the presence of a left-right symmetry in the system, we demonstrate that the efficiency at maximum power displays universality up to quadratic order in the deviation from equilibrium. A maser model is presented to illus

Hoonkyung Lee, Jisoon Ihm, Marvin L. Cohen, Steven G. Louie

Using first-principles calculations, we perform a search for high-capacity hydrogen storage media based on individually dispersed calcium atoms on doped or defective carbon nanotubes. We find that up to six H2 molecules can bind to a Ca atom each with a desirable binding energy of ~0.2 eV/H2. The hybridization of the empty Ca 3d states with the H2 sigma stat

Akaki Tikaradze

We show that the center of infinitesimal Cherednik algebras of gl_n is isomorphic to the polynomial algebra in n variables. Based on this we derive consequences for representation theory of these algebras.

Kiyoshi Igusa, Ralf Schiffler

We show that exceptional sequences for hereditary algebras are characterized by the fact that the product of the corresponding reflections is the inverse Coxeter element in the Weyl group. We use this result to give a new combinatorial characterization of clusters tilting sets in the cluster category in the case where the hereditary algebra is of finite type

John H. Elton, Theodore P. Hill

The conclusion of the classical ham sandwich theorem of Banach and Steinhaus may be strengthened: there always exists a common bisecting hyperplane that touches each of the sets, that is, intersects the closure of each set. Hence, if the knife is smeared with mayonnaise, a cut can always be made so that it will not only simultaneously bisect each of the ingr

Chris Blake, Russell Jurek, Sarah Brough, Matthew Colless

The WiggleZ Dark Energy Survey is a large-scale structure survey of intermediate-redshift UV-selected emission-line galaxies scheduled to cover 1000 sq deg, spanning a broad redshift range 0.2 < z < 1.0. The main scientific goal of the survey is the measurement of baryon acoustic oscillations (BAO) in the galaxy clustering pattern at a significantly higher r

Stefano Olivares, Matteo G. A. Paris

We address phase-shift estimation by means of squeezed vacuum probe and homodyne detection. We analyze Bayesian estimator, which is known to asymptotically saturate the classical Cramer-Rao bound to the variance, and discuss convergence looking at the a posteriori distribution as the number of measurements increases. We also suggest two feasible adaptive met

Sheng-wey Chiow, Sven Herrmann, Holger Mueller, Steven Chu

A modified Coherent 899-21 titanium sapphire laser is injection locked to produce 6-6.5 W of single-frequency light at 852 nm. After closed-loop amplitude control and frequency stabilization to a high-finesse cavity, it delivers 4-4.5 W with <1 kHz linewidth at the output of a single-mode fiber. The laser is tunable from about 700-1000 nm; up to 8 W should b

Samuel Gitler, Santiago Lopez de Medrano

The topology of the intersection of two real homogeneous coaxial quadrics was studied by the second author who showed that its intersection with the unit sphere is in most cases diffeomorphic to a connected sum of sphere products. Combining that approach with a recent one (due to Antony Bahri, Martin Bendersky, Fred Cohen and the first author) we study here

Y. Jack Ng, H. van Dam

The $(3 + 1)$-dimensional (generalized) Dirac equation is shown to have the same form as the equation expressing the condition that a given point lies on a given line in 3-dimensional projective space. The resulting Hamiltonian with a $γ_5$ mass term is not Hermitian, but is invariant under the combined transformation of parity reflection $\cal P$ and time r

Predrag Nikolic

We consider a generic two-dimensional system of fermionic particles with attractive interactions and no disorder. If time-reversal symmetry is absent, it is possible to obtain incompressible insulating states in addition to the superfluid at zero temperature. The superfluid-insulator phase transition is found to be second order in type-II systems using a per

Aaron R. Parsons, Donald C. Backer

We present a filtering technique that can be applied to individual baselines of wide-bandwidth, wide-field interferometric data to geometrically select regions on the celestial sphere that contain primary calibration sources. The technique relies on the Fourier transformation of wide-band frequency spectra from a given baseline to obtain one-dimensional &#34

Signe Riemer-Sorensen, Steen H. Hansen

Context. The sterile neutrino is an excellent dark matter candidate, which can be searched for in a wide range of astrophysical sites. It has previously been shown that the optimal search strategy is to consider dwarf galaxies belonging to the Milky Way. Aims. We search for line emission from decaying dark matter. Methods. We analyse publicly available Chand

Daniel Cibotaru

We describe a class of real Banach manifolds, which classify $K^{-1}$. These manifolds are Grassmannians of (hermitian) lagrangian subspaces in a complex Hilbert space. Certain finite codimensional real subvarieties described by incidence relations define geometric representatives for the generators of the cohomology rings of these classifying spaces. Any fa

Brendon LaBuz

Berestovskii and Plaut introduced the concept of a coverable uniform space when developing their theory of generalized universal covering maps for uniform spaces. Brodskiy, Dydak, LaBuz, and Mitra introduced the concept of a locally uniformly joinable uniform space when developing their theory of generalized uniform covering maps which was motivated by the w

M. A. Leonova, A. W. Chao, E. D. Courant, A. D. Krisch

This submission was withdrawn because of an unresolved dispute between the authors [arXiv admin 2009-4-13].

Aristophanes Dimakis, Folkert Muller-Hoissen

Quasi-symmetric functions show up in an approach to solve the Kadomtsev-Petviashvili (KP) hierarchy. This moreover features a new nonassociative product of quasi-symmetric functions that satisfies simple relations with the ordinary product and the outer coproduct. In particular, supplied with this new product and the outer coproduct, the algebra of quasi-sym

Hans De Raedt, Karl Hess, Kristel Michielsen

We address the basic meaning of apparent contradictions of quantum theory and probability frameworks as expressed by Bell&#39;s inequalities. We show that these contradictions have their origin in the incomplete considerations of the premisses of the derivation of the inequalities. A careful consideration of past work, including that of Boole and Vorob&#39;e

Justin Malestein, Andrew Putman

We give various estimates of the minimal number of self-intersections of a nontrivial element of the kth term of the lower central series and derived series of the fundamental group of a surface. As an application, we obtain a new topological proof of the fact that free groups and fundamental groups of closed surfaces are residually nilpotent. Along the way,

David Raske

In this note we establish the large time non-negativity of the heat kernel for a class of elliptic differential operators on closed, Riemannian manifolds, and apply this result to a problem from conformal differential geometry.

J. M. Drummond, M. Spradlin, A. Volovich, C. Wen

We present an algorithm for writing down explicit formulas for all tree amplitudes in N=8 supergravity, obtained from solving the supersymmetric on-shell recursion relations. The formula is patterned after one recently obtained for all tree amplitudes in N=4 super Yang-Mills which involves nested sums of dual superconformal invariants. We find that all gravi

Erik S. Thomson, Larry A. Wilen, John S. Wettlaufer

We develop a model for the reflection and transmission of plane waves by an isotropic layer sandwiched between two uniaxial crystals of arbitrary orientation. In the laboratory frame, reflection and transmission coefficients corresponding to the principal polarization directions in each crystal are given explicitly in terms of the c-axis and propagation dire

Jeremy Avigad

Almost from the inception of Hilbert&#39;s program, foundational and structural efforts in proof theory have been directed towards the goal of clarifying the computational content of modern mathematical methods. This essay surveys various methods of extracting computational information from proofs in classical first-order arithmetic, and reflects on some of

Emmanuel Nezri, Michel H. G. Tytgat, Gilles Vertongen

In the framework of the Inert Doublet Model, a very simple extension of the Standard Model, we study the production and propagation of antimatter in cosmic rays coming from annihilation of a scalar dark matter particle. We consider three benchmark candidates, all consistent with the WMAP cosmic abundance and existing direct detection experiments, and confron

Igor Iosilevskiy

Macroscopic plasma polarization, which is created by gravitation and other mass-acting (inertial) forces in massive astrophysical objects (MAO) is under discussion. Non-ideality effect due to strong Coulomb interaction of charged particles is introduced into consideration as a new source of such polarization. Simplified situation of totally equilibrium isoth

M. I. Tsindlekht, V. M. Genkin, G. I. Leviev, N. Yu. Shitsevalova

We present the results of an experimental study of the nucleation of superconductivity at the surface of a single crystal YB$_6$ in a tilted dc magnetic field. A recently developed experimental technique allowed us to determine $H_{c3}$ at each side of the sample as a function of the angle between the dc magnetic field and the surface. Experiment shows that

Igor Rivin

In this note we show that for any hyperbolic surface S, the number of geodesics of length bounded above by L in the mapping class group orbit of a fixed closed geodesic with a single double point is asymptotic to L raised to the dimension of the Teichmuller space of S. Since closed geodesics with one double point fall into a finite number of orbits under the

Jiunn-Wei Chen, Kenji Fukushima, Hiroaki Kohyama, Kazuaki Ohnishi

We discuss the chiral phase transition in hot and dense QCD with three light flavors. Inspired by the well known fact that the U_A(1) anomaly could induce first order phase transitions, we study the effect of the possible restoration of the U_A(1) symmetry at finite density. In particular, we explore the link between the U_A(1) restoration and the recent lat

Michael M. Wolf, David Perez-Garcia

Using tools from classical signal processing, we show how to determine the dimensionality of a quantum system as well as the effective size of the environment&#39;s memory from observable dynamics in a model-independent way. We discuss the dependence on the number of conserved quantities, the relation to ergodicity and prove a converse showing that a Hilbert

D. Gitman, A. Shelepin

We propose an approach to the quantum-mechanical description of relativistic orientable objects. It generalizes Wigner&#39;s ideas concerning the treatment of nonrelativistic orientable objects (in particular, a nonrelativistic rotator) with the help of two reference frames (space-fixed and body-fixed). A technical realization of this generalization (for ins

Jose D. Edelstein, Jonathan P. Shock, Dimitrios Zoakos

We aim at providing an overview on the applications of the AdS/CFT correspondence to non-perturbative aspects of non-Abelian gauge theories, addressed to particle physicists. The finite temperature case, in connection with the physics of the quark-gluon plasma, is emphasized.

Thomas Barnet-Lamb

In a previous paper, the potential automorphy of certain Galois representations to GL_n for n even was established, following work of Harris, Shepherd-Barron and Taylor and using the lifting theorems of Clozel, Harris and Taylor. In this paper, we extend those results to n=3 and n=5, and conditionally to all other odd n. The key additional tools necessary ar

Oscar Agertz, Romain Teyssier, Ben Moore

Observations of high redshift galaxies have revealed a multitude of large clumpy rapidly star-forming galaxies. Their formation scenario and their link to present day spirals is still unknown. In this Letter we perform adaptive mesh refinement simulations of disk formation in a cosmological context that are unrivalled in terms of mass and spatial resolution.

Francesca Da Lio, Tristan Riviere

We prove the regularity of weak 1/2-harmonic maps from the real line into a sphere. The key point in our result is first a formulation of the 1/2-harmonic map equation in the form of a non-local linear Schrödinger type equation with a 3-terms commutators in the right-hand-side . We then establish a sharp estimate for these 3-commutators.

Jean Alexandre, John Ellis, Nikolaos E. Mavromatos

It has been conjectured that four-dimensional N=8 supergravity may provide a suitable framework for a `Theory of Everything&#39;, if its composite SU(8) gauge fields become dynamical. We point out that supersymmetric three-dimensional coset field theories motivated by lattice models provide toy laboratories for aspects of this conjecture. They feature dynami

Zeev Dvir, Swastik Kopparty, Shubhangi Saraf, Madhu Sudan

We extend the &#34;method of multiplicities&#34; to get the following results, of interest in combinatorics and randomness extraction. (A) We show that every Kakeya set (a set of points that contains a line in every direction) in $\F_q^n$ must be of size at least $q^n/2^n$. This bound is tight to within a $2 + o(1)$ factor for every $n$ as $q \to \infty$, co

D. Obreschkow, S. Rawlings

We revisit the mass ratio Rmol between molecular hydrogen (H2) and atomic hydrogen (HI) in different galaxies from a phenomenological and theoretical viewpoint. First, the local H2-mass function (MF) is estimated from the local CO-luminosity function (LF) of the FCRAO Extragalactic CO-Survey, adopting a variable CO-to-H2 conversion fitted to nearby observati

R. Flume, A. Klitz

In view of the remarkable progress in the analysis of random matrix models during the last years we report on recent work of Eynard on the generation of a new cut in finite distance from the cuts given in the initial theory. This &#39;birth of a cut&#39; leads to a third order phase transition.

M. Risse

The Pierre Auger Observatory has a unique potential to search for ultra-high energy photons (above ~1 EeV). First experimental limits on photons were obtained during construction of the southern part of the Observatory. Remarkably, already these limits have proven useful to falsify proposals about the origin of cosmic rays, and to perform fundamental physics

Justin Feuto, Ibrahim Fofana, Konin Koua

The class of Banach spaces $(L^{q},L^{p}) ^α(X,d,μ)$, $1\leq q\leq α\leq p\leq \infty ,$ introduced in \cite{F1} in connection with the study of the continuity of the fractional maximal operator of Hardy-Littlewood and of the Fourier transformation in the case $% X=\mathbb{R}^{n}$ and $μ$ is the Lebesgue measure, was generalized in \cite{FFK} to the setting

P. S. Gutierrez, D. Monteoliva, L. Diambra

The origin of stochastic fluctuations in gene expression has received considerable attention recently. Fluctuations in gene expression are particularly pronounced in cellular systems because of the small copy number of species undergoing transitions between discrete chemical states and the small size of biological compartments. In this paper, we propose a st