October 2006 arXiv papers — page 51

Siegfried Echterhoff, Heath Emerson, Hyun Jeong Kim

Let the discrete group G act properly and isometrically on the Riemannian manifold X. Let C_0(X, δ) be the section algebra of a smooth locally trivial G-equivariant bundle of elementary C*-algebras representing an element δof the Brauer group Br_G(X). Then C_0(X,δ^{-1}) x G is KK-theoretically Poincare dual to (C_0(X,δ)\otimes_{C_0(X)} C_τ(X)) xG, where δ^{-

Herbi K. Dreiner, Olaf Kittel, Ulrich Langenfeld

We study radiative neutralino production e^+e^- \to \tildeχ^0_1 \tildeχ^0_1γat the linear collider with longitudinally polarised beams. We consider the Standard Model background from radiative neutrino production e^+e^- \to ν\barνγ, and the supersymmetric radiative production of sneutrinos e^+e^- \to \tildeν\tildeν^\ast γ, which can be a background for invis

W. A. Atkinson

The influence of static magnetic correlations on the temperature-dependent superfluid density ρ_s(T) is calculated for d-wave superconductors. In self-consistent calculations, itinerant holes form incommensurate spin density waves (SDW) which coexist with superconductivity. In the clean limit, the density of states is gapped, and ρ_s(T << T_c) is exponential

Pierluigi Monaco, Giuseppe Murante, Stefano Borgani, Fabio Fontanot

The high end of the stellar mass function of galaxies is observed to have little evolution since z~1. This represents a stringent constraint for merger--based models, aimed at explaining the evolution of the most massive galaxies in the concordance LambdaCDM cosmology. In this Letter we show that it is possible to remove the tension between the above observa

Thomas Kriete, Barbara MacCluer, Jennifer Moorhouse

Let $ϕ$ be a linear-fractional self map of the open unit disk, not an automorphism, such that $ϕ(ζ)=η$ for distinct points $ζ,η$ in the unit circle. We consider the question of which composition operators lie in the unital C*-algebra generated by the composition operator $C_ϕ$ and the ideal of compact operators, acting on the Hardy space $H^2$.

Daniel Zwanziger

We review recent analytic and numerical results concerning the confinement scenario in Coulomb gauge. We then consider a local, renormalizable, BRST-invariant action for QCD in Coulomb gauge that contains auxiliary bose and fermi ghost fields and sources. When the auxiliary fields are integrated out, one obtains the standard Coulomb gauge action with a cut-o

V. S. Pantuev

Predictions for some experimental physical observables in nucleus-nucleus collisions at RHIC energies are presented. I utilize the previous suggestion that the retarded, by time about 2-3 fm/c, jet absorption in opaque core is a natural explanation of many experimental data. This assumption is applied only to the particles with high transverse momentum above

J. D. Gibbon

More than 150 years after their invention by Hamilton, quaternions are now widely used in the aerospace and computer animation industries to track the paths of moving objects undergoing three-axis rotations. It is shown here that they provide a natural way of selecting an appropriate ortho-normal frame -- designated the quaternion-frame -- for a particle in

Günther Eichhorn, Alberto Accomazzi, Carolyn S. Grant, Edwin A. Henneken

The Smithsonian/NASA Astrophysics Data System (ADS) provides a search system for the astronomy and physics scholarly literature. All major and many smaller astronomy journals that were published on paper have been scanned back to volume 1 and are available through the ADS free of charge. All scanned pages have been converted to text and can be searched throu

Truong Le, Charles D. Dermer

A simple physical model for long-duration gamma ray bursts (GRBs) is used to fit the redshift (z) and the jet opening-angle distributions measured with earlier GRB missions and with Swift. The effect of different sensitivities for GRB triggering is sufficient to explain the difference in the z distributions of the pre-Swift and Swift samples, with mean redsh

Robin Pemantle

The models surveyed include generalized Pólya urns, reinforced random walks, interacting urn models, and continuous reinforced processes. Emphasis is on methods and results, with sketches provided of some proofs. Applications are discussed in statistics, biology, economics and a number of other areas.

Shinji Hirano

We consider a D-brane type state which shares the characteristic of the recently found giant magnon of Hofman and Maldacena. More specifically we find a bound state of giant graviton (D3-brane) and giant magnon (F-string), which has exactly the same anomalous dimension as that of the giant magnon. It is described by the D3-brane with electric flux which is t

C. M. Baugh

Recent observational and theoretical breakthroughs make this an exciting time to be working towards understanding the physics of galaxy formation. The goal of this review is to make the principles behind the hierarchical paradigm accessible to a wide audience by providing a pedagogical introduction to modern theories of galaxy formation. I outline the ingred

Vladislav Kargin

This paper derives sufficient conditions for superconvergence of sums of bounded free random variables and provides an estimate for the rate of superconvergence.

Vladislav Kargin

An analogue of the Berry-Esseen inequality is proved for the speed of convergence of free additive convolutions of bounded probability measures. The obtained rate of convergence is of the order n^{-1/2}, the same as in the classical case. An example with binomial measures shows that this estimate cannot be improved without imposing further restrictions on co

Matthew Buican, Dmitry Malyshev, David R. Morrison, Martijn Wijnholt

We report on progress towards the construction of SM-like gauge theories on the world-volume of D-branes at a Calabi-Yau singularity. In particular, we work out the topological conditions on the embedding of the singularity inside a compact CY threefold, that select hypercharge as the only light U(1) gauge factor. We apply this insight to the proposed open s

Vyacheslav Futorny, Serge Ovsienko

We solve the problem of extension of characters of commutative subalgebras in associative (noncommutative) algebras for a class of subrings (Galois orders) in skew group rings. These results can be viewed as a noncommutative analogue of liftings of prime ideals in the case of integral extensions of commutative rings. The proposed approach can be applied to t

Vyacheslav Futorny, Serge Ovsienko

We introduce and develop a structure theory of a new class of noncommutative rings - Galois orders, that generalize classical orders in noncommutative rings. Galois orders realized as certain subrings of invariants in skew semigroup rings. This class of rings contains many classical objects, in particular the Generalized Weyl algebras, the universal envelopi

A. L. Knutsen, A. F. Lopez

Let $L$ be a line bundle on a K3 or Enriques surface. We give a vanishing theorem for $H^1(L)$ that, unlike most vanishing theorems, gives necessary and sufficient geometrical conditions for the vanishing. This result is essential in our study of Brill-Noether theory of curves on Enriques surfaces (reference [KL1]) and of Enriques-Fano threefolds (reference

Changhyun Ahn

The M-theory lift for the supersymmetry breaking IIA brane configuration corresponding to the meta-stable state of N=1 unitary supersymmetric Yang-Mills theory with massive flavors was found by Bena et al(hep-th/0608157) recently. We extend this to symplectic and orthogonal gauge groups by analyzing the previously known results on M-theory lifts of supersymm

Philipp Gerhold, Karl Jansen

In the past the construction of Higgs-Yukawa models on the lattice was blocked by the lack of a consistent definition of a chiral invariant Yukawa coupling term. Here, we consider a chiral invariant Higgs-Yukawa model based on the overlap operator, realized by the Neuberger-Dirac operator. As a first step towards a numerical examination of this model we stud

M. Aldenius, J. D. Tanner, S. Johansson, H. Lundberg

The stellar abundance ratio of Mg/Fe is an important tool in diagnostics of galaxy evolution. In order to make reliable measurements of the Mg abundance of stars, it is necessary to have accurate values for the oscillator strength (f-value) of each of the observable transitions. In metal-poor stars the Mg I 3p-4s triplet around 5175 AA (Fraunhofer&#39;s so-c

L. J. P. Kilford

In this note we generalise a method of Perott to give new proofs that there are infinitely many prime numbers.

Yan V. Fyodorov, H. -J. Sommers

We investigate thermodynamics of a single classical particle placed in a spherical box of a finite radius $R$ and subject to a superposition of a $N-$dimensional Gaussian random potential and the parabolic potential with the curvature $μ>0$. Earlier solutions of $R\to \infty$ version of this model were based on combining the replica trick with the Gaussian V

J. D. Vergados, Ch. C. Moustakidis, V. Oikonomou

The event rates for the direct detection of dark matter for various types of WIMPs are presented. In addition to the neutralino of SUSY models, we considered other candidates (exotic scalars as well as particles in Kaluza-Klein and technicolour theories) with masses in the TeV region. Then one finds reasonable branching ratios to excited states. Thus the det

J. L. Jaramillo, M. Ansorg, F. Limousin

We study the numerical implementation of a set of boundary conditions derived from the isolated horizon formalism, and which characterize a black hole whose horizon is in quasi-equilibrium. More precisely, we enforce these geometrical prescriptions as inner boundary conditions on an excised sphere, in the numerical resolution of the Conformal Thin Sandwich e

Christian Kunert, Jens Harting

Substantial experimental, theoretical, as well as numerical effort has been invested to understand the effect of boundary slippage in microfluidic devices. However, even though such devices are becoming increasingly important in scientific, medical, and industrial applications, a satisfactory understanding of the phenomenon is still lacking. This is due to t

Alex Degtyarev, Ilia Itenberg, Viatcheslav Kharlamov

We study real elliptic surfaces and trigonal curves (over a base of an arbitrary genus) and their equivariant deformations. We calculate the real Tate-Shafarevich group and reduce the deformation classification to the combinatorics of a real version of Grothendieck&#39;s {\it dessins d&#39;enfants}. As a consequence, we obtain an explicit description of the

Ch. Hartnack, H. Oeschler, Jörg Aichelin

In astrophysics as well as in hadron physics progress has recently been made on the determination of the hadronic equation of state (EOS) of compressed matter. The results are contradictory, however. Simulations of heavy ion reactions are now sufficiently robust to predict the stiffness of the (EOS) from (i) the energy dependence of the ratio of $K^+$ from A

C. Beck

The influence on the fusion process of coupling to collective degrees of freedom has been explored. The significant enhancement of the fusion cross section at sub-barrier energies was compared to predictions of one-dimensional barrier penetration models. This was understood in terms of the dynamical processes arising from strong couplings to collective inela

Adrian Paschke

In this paper we elaborate on a specific application in the context of hybrid description logic programs (hybrid DLPs), namely description logic Semantic Web type systems (DL-types) which are used for term typing of LP rules based on a polymorphic, order-sorted, hybrid DL-typed unification as procedural semantics of hybrid DLPs. Using Semantic Web ontologies

Fedele Lizzi

In this paper I discuss connections between the noncommutative geometry approach to the standard model on one side, and the internal space coming from strings on the other. The standard model in noncommutative geometry is described via the spectral action. I argue that an internal noncommutative manifold compactified at the renormalization scale, could give

S. V. Kukhlevsky

The extra energy, negative energy and annihilation of energy by the subwavelength conservative systems that have a wave nature of light or matter (quantum) objects are predicted. The creating and destroying of energy break the energy conservation law in any subwavelength physical system. The paradoxical phenomenon is demonstrated in the context of extraordin

Varun Sahni, Alexei Starobinsky

This review summarizes recent attempts to reconstruct the expansion history of the Universe and to probe the nature of dark energy. Reconstruction methods can be broadly classified into parametric and non-parametric approaches. It is encouraging that, even with the limited observational data currently available, different approaches give consistent results f

Nam-Hoon Lee

This note is a report on the observation that some singular varieties admit Calabi--Yau coverings. As an application, we construct 18 new Calabi--Yau 3-folds with Picard number one that have some interesting properties.

Katsunori Kawamura

It is often inevitable to introduce an indefinite-metric space in quantum field theory, for example, which is explained for the sake of the manifestly covariant quantization of the electromagnetic field. We show two more evident mathematical reasons why such indefinite metric appears. The first idea is the replacement of involution on an algebra. For an alge

Zhao Zheng, Tian Guihua, Liu Liao

There are two important basic questions in the measurement of time. The first one is how to define the simultaneity of two events occurring at two different places. The second one is how to define the equality of two durations. The first question has been solved by Einstein, Landau and others on the convention that the velocity of light is isotropic and it i

R. Foot, R. R. Volkas

It has recently been pointed out that the mirror or twin Higgs model is more technically natural than the standard model, thus alleviating the ``little&#39;&#39; hierarchy problem. In this paper we generalise the analysis to models with an arbitrary number of isomorphic standard model sectors, and demonstrate that technical naturalness increases with the num

David Brander

We study two aspects of the loop group formulation for isometric immersions with flat normal bundle of space forms. The first aspect is to examine the loop group maps along different ranges of the loop parameter. This leads to various equivalences between global isometric immersion problems among different space forms and pseudo-Riemannian space forms. As a

Alexander Beilinson

The article describes a purely topological counterpart of the $ε$-factorization of constants in the functional equations (which is a key ingredient in the interplay between L-functions and classical automorphic forms). We consider the determinant of the cohomology of a constructible sheaf F on a real analytic manifold X (or a bit more precise object, which i

Kazuyuki Fujii, Tatsuo Suzuki

A closed expression to the Baker-Campbell-Hausdorff (B-C-H) formula in SO(4) is given by making use of the magic matrix by Makhlin. As far as we know this is the {\bf first nontrivial example} on (semi-) simple Lie groups summing up all terms in the B-C-H expansion.

Hideo Hasegawa

We have studied the dynamical properties of finite $N$-unit FitzHugh-Nagumo (FN) ensembles subjected to additive and/or multiplicative noises, reformulating the augmented moment method (AMM) with the Fokker-Planck equation (FPE) method [H. Hasegawa, J. Phys. Soc. Jpn. {\bf 75}, 033001 (2006)]. In the AMM, original $2N$-dimensional stochastic equations are tr

Yanfeng Chen, Mikhail Khovanov

We construct an explicit categorification of the action of tangles on tensor powers of the fundamental representation of quantum sl(2).

Adrian Kent

If mutually mistrustful parties A and B control two or more appropriately located sites, special relativity can be used to guarantee that a pair of messages exchanged by A and B are independent. In earlier work, we used this fact to define a relativistic bit commitment protocol, RBC1, in which security is maintained by exchanging a sequence of messages whose

Neil V. Budko, Alexander B. Samokhin

A new class of generalized solutions related to the essential spectrum of linear Maxwell&#39;s equations is presented. The essential modes are given in terms of normalized singular Weyl&#39;s sequences, whose square represents Dirac&#39;s delta functions in spatial and angular frequency domains. The action integral associated with essential modes is well-def

Shin I. Nishimura, Masaki Sasai

Morphologies of moving amoebae are categorized into two types. One is the ``neutrophil&#39;&#39; type in which the long axis of cell roughly coincides with its moving direction. This type of cell extends a leading edge at the front and retracts a narrow tail at the rear, whose shape has been often drawn as a typical amoeba in textbooks. The other one is the

Edward R Abraham

Sea urchin feeding fronts are a striking example of spatial pattern formation in an ecological system. If it is assumed that urchins are asocial, and that they move randomly, then the formation of these dense fronts is an apparent paradox. The key lies in observations that urchins move further in areas where their algal food is less plentiful. This naturally

Laszlo B. Kish

We outline some general solutions to use already existing and currently used wire lines, such as power lines, phone lines, internet lines, etc, for the unconditionally secure communication method based on Kirchoff&#39;s Law and Johnson-like Noise (KLJN). Two different methods are shown. One is based on filters used at single wires and the other one utilizes

Stephan Gekle, Jörg Main, Thomas Bartsch, T. Uzer

A hierarchical ordering is demonstrated for the periodic orbits in a strongly coupled multidimensional Hamiltonian system, namely the hydrogen atom in crossed electric and magnetic fields. It mirrors the hierarchy of broken resonant tori and thereby allows one to characterize the periodic orbits by a set of winding numbers. With this knowledge, we construct

Stefan A. Maier, Steve R. Andrews, L. Martín-Moreno, F. J. García-Vidal

In this letter we show how the dispersion relation of surface plasmon polaritons (SPPs) propagating along a perfectly conducting wire can be tailored by corrugating its surface with a periodic array of radial grooves. In this way, highly localized SPPs can be sustained in the terahertz region of the electromagnetic spectrum. Importantly, the propagation char

Klaus Gottstein

On the occasion of Carl Friedrich von Weizsaecker&#39;s 81st birthday, a colloquium was held on July 3, 1993. One of the topics was &#34;The epistemological foundation of physics from Kant to von Weizsaecker&#34;. I took part in the discussion. Afterwards I got the impression that I had not succeeded in making my points clear. Therefore, I wrote an explanato

Vasily E. Tarasov

Electric and magnetic fields of fractal distribution of charged particles are considered. The fractional integrals are used to describe fractal distribution. The fractional integrals are considered as approximations of integrals on fractals. Using the fractional generalization of integral Maxwell equation, the simple examples of the fields of homogeneous fra

E. Svoukis, H. Tsertos

In situ, high-resolution, gamma-ray spectrometry of a total number of 70 outdoor and 20 indoor representative measurements were performed in preselected, common locations of the main urban areas of Cyprus. Specific activities and gamma absorbed dose rates in air due to the naturally occurring radionuclides of Th-232 and U-238 series, and K-40 are determined

Kwang-Hua W. Chu

We make comments on Kim and Chan&#39;s [{\it Phys. Rev. Lett.} 97, 115302 (2006)] letter. Based on their pressure-dependent measurements (by a torsional oscillator technique), we propose that the {\it supersolid} fraction ($ρ_s/ρ$) might be relevant to an sound absorption or attenuation (fluctuations of pressure waves) in microscopic domain since there is no

P. Chomaz, C. Ducoin, F. Gulminelli, K. H. O. Hasnaoui

In the formation and evolution of compact stars, nuclear matter explores high thermal excursions and is the site of intense neutrino emission. Neutrino transport as well as structural properties of this matter depend on the presence of inhomogeneous phases (named &#34;pasta&#34; phases), which are the result of Coulomb frustration of the Liquid-Gas phase tra

H. Liu, Ch. Elster, W. Gloeckle

The Faddeev equation for three-body scattering at arbitrary energies is formulated in momentum space and directly solved in terms of momentum vectors without employing a partial wave decomposition. For identical bosons this results in a three-dimensional integral equation in five variables, magnitudes of relative momenta and angles. The cross sections for bo

Carl M. Bender, Dorje C. Brody, Junhua Chen, Elisabetta Furlan

The Korteweg-de Vries equation u_t+uu_x+u_{xxx}=0 is PT symmetric (invariant under space-time reflection). Therefore, it can be generalized and extended into the complex domain in such a way as to preserve the PT symmetry. The result is the family of complex nonlinear wave equations u_t-iu(i u_x)^epsilon+u_{xxx}=0, where epsilon is real. The features of thes

Ioan Bejenaru, Daniel Tataru

We consider the Derivative NLS equation with general quadratic nonlinearities. In \cite{be2} the first author has proved a sharp small data local well-posedness result in Sobolev spaces with a decay structure at infinity in dimension $n = 2$. Here we prove a similar result for large initial data in all dimensions $n \geq 2$.

Paolo Lipparini

We give examples and counterexamples concerning varieties in which every tolerance is representable as $R \circ R^-$, for some reflexive and admissible relation $R$.

Alan Hammond, Fraydoun Rezakhanlou

We prove uniform bounds on moments X_a = \sum_{m}{m^a f_m(x,t)} of the Smoluchowski coagulation equations with diffusion, valid in any dimension. If the collision propensities α(n,m) of mass n and mass m particles grow more slowly than (n+m)(d(n) + d(m)), and the diffusion rate d(\cdot) is non-increasing and satisfies m^{-b_1} \leq d(m) \leq m^{-b_2} for som

Itai Benjamini, Carlos Hoppen, Eran ofek, Pawel Pralat

A geodesic in a graph G is a shortest path between two vertices of G. For a specific function e(n) of n, we define an almost geodesic cycle C in G to be a cycle in which for every two vertices u and v in C, the distance d_G(u,v) is at least d_C(u,v)-e(n). Let f(n) be any function tending to infinity with n. We consider a random d-regular graph on n vertices.

D. W. Browne, M. W. Browne, M. P. Fitz

Singular Value Decomposition (SVD) is a powerful tool for multivariate analysis. However, independent computation of the SVD for each sample taken from a bandlimited matrix random process will result in singular value sample paths whose tangled evolution is not consistent with the structure of the underlying random process. The solution to this problem is de

Weimin Chen

This is the second of a series of papers which are devoted to a comprehensive theory of maps between orbifolds. In this paper, we develop a basic machinery for studying homotopy classes of such maps. It contains two parts: (1) the construction of a set of algebraic invariants -- the homotopy groups, and (2) an analog of CW-complex theory. As a corollary of t

Ralph M. Kaufmann

We combine our results on symmetric products and second quantization with our description of discrete torsion in order to explain the ring structure of the cohomology of the Hilbert scheme of points on a K3 surface. This is achieved in terms of an essentially unique symmetric group Frobenius algebra twisted by a specific discrete torsion. This twist is reali

Richard Atkins

This paper investigates the relationship between a system of differential equations and the underlying geometry associated with it. The geometry of a surface determines shortest paths, or geodesics connecting nearby points, which are defined as the solutions to a pair of second-order differential equations: the Euler-Lagrange equations of the arclength actio

Denis S. Grebenkov

Transport phenomena are ubiquitous in nature and known to be important for various scientific domains. Examples can be found in physics, electrochemistry, heterogeneous catalysis, physiology, etc. To obtain new information about diffusive or Laplacian transport towards a semi-permeable or resistive interface, one can study the random trajectories of diffusin

G. Dafni, G. E. Karadzhov, J. Xiao

We introduce classes of measures in the half-space $\mathbf{R}^{n+1}_+,$ generated by Riesz, or Bessel, or Besov capacities in $\mathbf{R}^n$, and give a geometric characterization as Carleson-type measures.

X. Duong, L. Yan, J. Xiao

Given $p\in [1,\infty)$ and $λ\in (0,n)$, we study Morrey space ${\rm L}^{p,λ}({\mathbb R}^n)$ of all locally integrable complex-valued functions $f$ on ${\mathbb R}^n$ such that for every open Euclidean ball $B\subset{\mathbb R}^n$ with radius $r_B$ there are numbers $C=C(f)$ (depending on $f$) and $c=c(f,B)$ (relying upon $f$ and $B$) satisfying $$ r_B^{-λ

Der-Chen Chang, Irina Markina

We study the relations between the quaternion $H$-type group and the boundary of the unit ball on two dimensional quaternionic space. The orthogonal projection of the space of square integrable functions defined on quaternion $H$-type group into its subspace of boundary values of $q$-holomorphic functions is consider. The precise form of Cauchy-Szego kernel

S. D. Galbraith, B. A. Smith

Déchène has proposed generalized Jacobians as a source of groups for public-key cryptosystems based on the hardness of the Discrete Logarithm Problem (DLP). Her specific proposal gives rise to a group isomorphic to the semidirect product of an elliptic curve and a multiplicative group of a finite field. We explain why her proposal has no advantages over simp

Der-Chen Chang, Irina Markina

We construct examples of 2-step Carnot groups related to quaternions and study their fine structure and geometric properties. This involves the Hamiltonian formalism, which is used to obtain explicit equations for geodesics and the computation of the number of geodesics joining two different points on these groups. We able to find the explicit lengths of geo

Narad Rampersad

We show that the set of binary words containing overlaps is not unambiguously context-free and that the set of ternary words containing overlaps is not context-free. We also show that the set of binary words that are not subwords of the Thue-Morse word is not unambiguously context-free.

Sergey Pinchuk, Alexandre Sukhov

We study the holomorphic extendability of smooth CR maps between real analytic strictly pseudoconvex hypersurfaces in complex affine spaces of different dimensions.

Christian Bonatti, Sylvain Crovisier, Amie Wilkinson

On the one hand, we prove that the spaces of C^1 symplectomorphisms and of C^1 volume-preserving diffeomorphisms both contain residual subsets of diffeomorphisms whose centralizers are trivial. On the other hand, we show that the space of C^1 diffeomorphisms of the circle and a non-empty open set of C^1 diffeomorphisms of the two-sphere contain dense subsets

Rafael López

In this paper we consider a free boundary problem in the 3-dimensional Lorentz-Minkowski space $ł^3$ which deals spacelike surfaces whose mean curvature is a linear function of the time coordinate and the boundary moves in a given support plane. We study spacelike surfaces that project one-to-one into a strip of the support and that locally are critical poin

Dimitrios Cheliotis

According to a theorem of S. Schumacher, for a diffusion X in an environment determined by a stable process that belongs to an appropriate class and has index a, it holds that X_t/(log t)^a converges in distribution, as t goes to infinity, to a random variable having an explicit description in terms of the environment. We compute the density of this random v

Dimitrios Cheliotis

For any recurrent random walk (S_n)_{n>0} on R, there are increasing sequences (g_n)_{n>0} converging to infinity for which (g_n S_n)_{n>0} has at least one finite accumulation point. For one class of random walks, we give a criterion on (g_n)_{n>0} and the distribution of S_1 determining the set of accumulation points for (g_n S_n)_{n>0}. This extends, with

Ivan Cheltsov

We prove the factoriality of a nodal hypersurface in $\mathbb{P}^{4}$ of degree $d$ that has at most $2(d-1)^{2}/3$ singular points, and factoriality of a double cover of $\mathbb{P}^{3}$ branched over a nodal surface of degree $2r$ having less than $(2r-1)r$ singular points.

Tom Braden

We review the theory of combinatorial intersection cohomology of fans developed by Barthel-Brasselet-Fieseler-Kaup, Bressler-Lunts, and Karu. This theory gives a substitute for the intersection cohomology of toric varieties which has all the expected formal properties but makes sense even for non-rational fans, which do not define a toric variety. As a resul

Christopher Hoffman, Alexander E. Holroyd, Yuval Peres

Let $Ξ$ be a discrete set in ${\mathbb{R}}^d$. Call the elements of $Ξ$ centers. The well-known Voronoi tessellation partitions ${\mathbb{R}}^d$ into polyhedral regions (of varying sizes) by allocating each site of ${\mathbb{R}}^d$ to the closest center. Here we study ``fair&#39;&#39; allocations of ${\mathbb{R}}^d$ to $Ξ$ in which the regions allocated to d

Sergey Mozgovoy

We classify (semi)stable sheaves on a rational curve with one node. The results are based on the classification of indecomposable torsion-free sheaves due to Drozd and Greuel &#34;Tame and wild projective curves and classification of vector bundles&#34;, where the sheaves are described in terms of certain combinatorial data. We translate the condition of (se

Apoloniusz Tyszka

Let F be a subfield of a commutative field extending R. Let phi_n:F^n \times F^n ->F, phi_n((x_1,...,x_n),(y_1,...,y_n))=(x_1-y_1)^2+...+(x_n-y_n)^2. We say that f:R^n->F^n preserves distance d>=0 if for each x,y \in R^n |x-y|=d implies phi_n(f(x),f(y))=d^2. Let A_n(F) denote the set of all positive numbers d such that any map f:R^n->F^n that preserves unit

Jutta Kunz, Francisco Navarro-Lerida

Charged rotating black holes of Einstein-Maxwell-Chern-Simons theory in odd dimensions, $D \ge 5$, may possess a negative horizon mass, while their total mass is positive. This surprising feature is related to the existence of counterrotating solutions, where the horizon angular velocity $Ω$ and the angular momentum $J$ possess opposite signs. Black holes ma

Francis Bursa, Michael Teper

We find a strong-to-weak coupling cross-over in D=2+1 SU(N) lattice gauge theories that appears to become a third-order phase transition at N=\infty, in a similar way to the Gross-Witten transition in the D=1+1 SU(N\to\infty) lattice gauge theory. There is, in addition, a peak in the specific heat at approximately the same coupling that increases with N, whi

Michael A. Ivanov

Graviton pairing and destruction of these pairs under collisions with bodies may lead to the Newtonian attraction. It opens us a new way to a very-low-energy quantum gravity model. In the model by the author, cosmological redshifts are caused by interactions of photons with gravitons of the background. Non-forehead collisions with gravitons lead to an additi

D. Bazeia, L. Losano, J. J. Rodrigues

We present a general procedure to solve the equations of motion for cosmological models driven by real scalar fields with first-order differential equations. The method seems to have great power, since it works for closed, flat or open space-time, for scalar fields with both standard and tachyonic dynamics. We illustrate the procedure solving several example

Kang-Sin Choi

We elaborate that general intersecting brane models on orbifolds are obtained from type I string compactifications and their T-duals. Symmetry breaking and restoration occur via recombination and parallel separation of branes, preserving supersymmetry. The Ramond-Ramond tadpole cancelation and the toron quantization constrain the spectrum as a branching of t

C. Adam, J. Sanchez-Guillen, A. Wereszczynski

The application of a weak integrability concept to the Skyrme and $CP^n$ models in 4 dimensions is investigated. A new integrable subsystem of the Skyrme model, allowing also for non-holomorphic solutions, is derived. This procedure can be applied to the massive Skyrme model, as well. Moreover, an example of a family of chiral Lagrangians providing exact, fi

Alejandro Gaona, J. Antonio Garcia

We consider some aspects of classical S-duality transformations in first order actions taken into account the general covariance of the Dirac algorithm and the transformation properties of the Dirac bracket. By classical S-Duality transformations we mean a field redefinition that interchanges the equations of motion and its associated Bianchi identities. By

Jonathan J. Heckman, Cumrun Vafa

It has recently been shown that the statistical mechanics of crystal melting maps to A-model topological string amplitudes on non-compact Calabi-Yau spaces. In this note we establish a one to one correspondence between two and three dimensional crystal melting configurations and certain BPS black holes given by branes wrapping collapsed cycles on the orbifol

Luis A. Anchordoqui

Motivated by recent interest in TeV-scale gravity and especially by the possibility of fast baryon decay mediated by virtual black holes, we study another dangerous aspect of spacetime foam interactions: lepton flavor violation. We correlate existing limits on gravity-induced decoherence in the neutrino sector with a lower bound on the scale of quantum gravi

Frithjof Karsch

We discuss results from lattice calculations for a few observables that are sensitive to different length scales in the high temperature phase of QCD and can give insight into its non-perturbative structure. We compare lattice results with perturbative calculations at high temperature obtained for vanishing and non-vanishing quark chemical potential.

G. Balossini, C. M. Carloni Calame, G. Montagna, O. Nicrosini

A new version of the event generator BABAYAGA is presented, which is based on an original matching of the Parton Shower approach with the complete exact O(alpha) matrix element for the inclusion of the QED radiative corrections to the Bhabha process at flavour factories. The theoretical accuracy of the improved generator is conservatively estimated to be 0.2

Robi Peschanski

When quarks and gluons are led to form a dense medium, like in high energy or/and heavy-ion collisions, it is interesting to ask the question which are the relevant degrees of freedom that Quantum Chromodynamics predict. The present notes correspond to two lectures given at Zakopane in the (rainy) summer of 2006, where this question is adressed concretely in

C. M. Carloni Calame, G. Montagna, O. Nicrosini, A. Vicini

A concise review about the status of the calculation of radiative corrections to the Drell-Yan processes is presented. The effect of matching together exact electroweak O(alpha) corrections with higher-order QED effects due to multiple photon emission is displayed in some physical distributions in the charged current channel, which have obtained with the new

Wolfgang Lucha, F. F. Schoberl

A three-dimensional reduction of the homogeneous Bethe-Salpeter equation retaining, in contrast to the Salpeter equation, the exact propagators (crucial for, e.g., a proper incorporation of dynamical chiral symmetry breakdown) is proposed. This formalism may be easily extended to Bethe-Salpeter equations for bound states composed of particles that are not, o

J. Berges, Sz. Borsanyi

We review recent developments and open questions for the description of nonequilibrium quantum fields, continuing hep-ph/0302210 and hep-ph/0410330.

G. A. Kozlov, G. Khoriauli

We consider the phase transition in the &#34;hot&#34; dual long-distances Yang-Mills theory at finite temperature $T$. This phase transition is associated with a change of symmetry. The dual model is formulated in terms of two-point Wightman functions with equations of motion involving higher derivatives. The effective mass of the dual gauge field is derived

S. F. King, S. Moretti, R. Nevzorov

In this talk we discuss an $E_6$ inspired supersymmetric (SUSY) model with an extra $U(1)_{N}$ gauge symmetry under which right-handed neutrinos have zero charge. In this exceptional supersymmetric standard model (E$_6$SSM) the $μ$-term is generated dynamically after the electroweak symmetry breaking. We specify the particle content of the model and argue th

W. Detmold, B. C. Tiburzi, A. Walker-Loud

We discuss the extraction of the electromagnetic and spin polarisabilities of nucleons from lattice QCD. We show that the external field method can be used to measure all the electromagnetic and spin polarisabilities including those of charged particles. We then turn to the extrapolations required to connect such calculations to experiment in the context of