February 2006 arXiv papers — page 14

Holger B. Nielsen, Masao Ninomiya

It is shown that if physical space time were truly compact there would only be of the order of one solutions to the classical field equations with a weighting to be explained. But that would not allow any peculiar choice of initial conditions that could support a non-trivial second law of thermodynamics. We present a no-go theorem: Irreversible processes wou

D. V. Vassilevich

It has been proposed that the Poincare and some other symmetries of noncommutative field theories should be twisted. Here we extend this idea to gauge transformations and find that twisted gauge symmetries close for arbitrary gauge group. We also analyse twisted-invariant actions in noncommutative theories.

Isabel M. C. Salavessa

We consider spacelike graphs $Γ_f$ of simple products $(M\times N, g\times -h)$ where $(M,g)$ and $(N,h)$ are Riemannian manifolds and $f:M\to N$ is a smooth map. Under the condition of the Cheeger constant of $M$ to be zero and some condition on the second fundamental form at infinity, we conclude that if $Γ_f \subset M\times N$ has parallel mean curvature

Vyacheslav Boyko, Jiri Patera, Roman Popovych

A new purely algebraic algorithm is presented for computation of invariants (generalized Casimir operators) of Lie algebras. It uses the Cartan's method of moving frames and the knowledge of the group of inner automorphisms of each Lie algebra. The algorithm is applied, in particular, to computation of invariants of real low-dimensional Lie algebras. A n

Gregg Musiker, James Propp

Fomin and Zelevinsky show that a certain two-parameter family of rational recurrence relations, here called the (b,c) family, possesses the Laurentness property: for all b,c, each term of the (b,c) sequence can be expressed as a Laurent polynomial in the two initial terms. In the case where the positive integers b,c satisfy bc<4, the recurrence is related to

C. Chicone, B. Mashhoon

The motion of free nearby test particles relative to a stable equatorial circular geodesic orbit about a Kerr source is investigated. It is shown that the nonlinear generalized Jacobi equation can be transformed in this case to an autonomous form. Tidal dynamics beyond the critical speed c/sqrt(2) is studied. We show, in particular, that a free test particle

Tien D. Kieu

We give a mathematical proof for an identification criterion by a probability measure for the ground state among an infinite number of available states, or a finitely truncated number with appropriate boundary conditions, in a quantum adiabatic algorithm for Hilbert&#39;s tenth problem.

Tien D. Kieu

We study a set of truncated matrices, given by Smith~\cite{Smith2005}, in connection to an identification criterion for the ground state in our proposed quantum adiabatic algorithm for Hilbert&#39;s tenth problem. We identify the origin of the trouble for this truncated example and show that for a suitable choice of some parameter it can always be removed. W

Yomen Atassi, Mohammad Tally

Mg-Cu-Zn ferrite was prepared through a wet synthetic method by a self-combustion reaction directly from a citrate precursor. The as-synthesized powders were sintered at for only 2h. XRD patterns and FTIR spectra confirm the formation of single phase Mg-Cu-Zn ferrite after combustion. To the best of our knowledge, this is the first time that Mg-Cu-Zn ferrite

V. P. Dmitriyev

Small perturbations of averaged ideal turbulence reproduce the electromagnetic field. The luminiferous medium has the relatively low pressure and high energy. A vapor bubble in the fluid models the neutron. The bubble stabilized via creating in the fluid a field of the positive perturbation of the turbulence energy serves as a model of the proton. An isle of

Jenny Lee, M. B. Tsang, W. G. Lynch

The present paper examines past measurements of the angular distributions for (d,p) and (p,d) reactions on targets with Z=3-24 leading to the ground states. The procedure is prescribed for extracting a conventional set of spectroscopic factors. Most of these spectroscopic factors agree well with large-basis shell model predictions. In all, the ground state n

Kazumasa Nomura, Paul Terwilliger

Let $K$ denote a field, and let $V$ denote a vector space over $K$ with finite positive dimension. We consider a pair of linear transformations $A:V \to V$ and $A^*:V \to V$ that satisfy (i), (ii) below: (i) There exists a basis for $V$ with respect to which the matrix representing $A$ is irreducible tridiagonal and the matrix representing $A^*$ is diagonal.

G. Barthel, J. -P-Brasselet, K. -H. Fieseler, L. Kaup

The paper presents a proof of the Hodge Riemann relations for the combinatorial intersection cohomology of a polytope, as fist given by K.Karu, in terms of geometric operations on polytopes.

Masaki Izumi, Sergey Neshveyev, Rui Okayasu

We consider the harmonic measure on the Gromov boundary of a nonamenable hyperbolic group defined by a finite range random walk on the group, and study the corresponding orbit equivalence relation on the boundary. It is known to be always amenable and of type III. We determine its ratio set by showing that it is generated by certain values of the Martin kern

Martin Schmoll

We study modular fibers of elliptic differentials, which are roughly spaces of torus-coverings over a fixed base torus. For genus 2 torus covers with fixed degree we show, that the modular fibers F_d(1,1) are itself connected torus covers with Veech group SL_2(Z). Using results of Eskin, Masur and Schmoll we calculate the Euler Characteristic and the parity

Donald Yau

An algebraic deformation theory of algebras over the Landweber-Novikov algebra is obtained.

Marcelo Gleiser

The basic properties of oscillons -- localized, long-lived, time-dependent scalar field configurations -- are briefly reviewed, including recent results demonstrating how their existence depends on the dimensionality of spacetime. Their role on the dynamics of phase transitions is discussed, and it is shown that oscillons may greatly accelerate the decay of

A. Gorsky

The brief review of the duality between gauge theories and closed strings propagating in the curved space is based on the lectures given at ITEP Winter School - 2005

D. G. Coyne

A different reason for the apparent weakness of the gravitational interaction is advanced, and its consequences for Hawking evaporation of a Schwarzschild black hole are investigated. A simple analytical formulation predicts that evaporating black holes will undergo a type of phase transition resulting in variously long-lived objects of reasonable sizes, wit

Lang Yu, Xiao-Lin Chen, Wei-Zhen Deng, Shi-Lin Zhu

The chiral quark model gives a reasonably good description of many low-energy observables by incorporating the effective degrees carried by the constituent quarks and Goldstone bosons. We calculate the decuplet to octet transition magnetic moments and the decay widths of several excited hyperons using this model. The various radiative decay widths from the c

E. O. Iltan

We study the branching ratios of the lepton flavor violating processes μ-> eγ, τ-> eγand τ-> μγby considering that the new Higgs scalars localize with Gaussian profile in the extra dimension. We see that the BRs of the LFV decays μ-> e γ, τ-> e γand τ-> μγare at the order of the magnitude of 10^{-12}, 10^{-16} and 10^{-12} in the considered range of the free

Ralf Lehnert

The violation of spacetime symmetries provides a promising candidate signal for underlying physics, possibly arising at the Planck scale. This talk gives an overview over various aspects in the field, including some mechanisms for Lorentz breakdown, the SME test framework, and phenomenological signatures for such effects.

Merced Montesinos

After reviewing the covariant description of Hamiltonian dynamics, some applications are done to the non-relativistic isotropic three-dimensional harmonic oscillator, Rovelli&#39;s model, and SO(3,1) BF theories.

K. R. Koehler

We present a practical application of parallel symbolic computation in General Relativity: the calculation of curvature invariants for large dimension. We discuss the structure of the calculations, an implementation of the technique and scaling of the computation with spacetime dimension for various invariants.

P. F. Gora

A system with two correlated Gaussian white noises is analysed. This system can describe both stochastic localization and long tails in the stationary distribution. Correlations between the noises can lead to a nonmonotonic behaviour of the variance as function of the intensity of one of the noises and to a stochastic resonance. A method for improving the tr

V. Zdravkov, A. Sidorenko, G. Obermeier, S. Gsell

We report on the first observation of a pronounced re-entrant superconductivity phenomenon in superconductor/ferromagnetic layered systems. The results were obtained using a superconductor/ferromagnetic-alloy bilayer of Nb/Cu(1-x)Ni(x). The superconducting transition temperature T_{c} drops sharply with increasing thickness d_{CuNi} of the ferromagnetic laye

A. Cavallo, F. Cosenza, L. De Cesare

In this article we review a less known unperturbative and powerful many-body method in the framework of classical statistical mechanics and then we show how it works by means of explicit calculations for a nontrivial classical model. The formalism of two-time Green functions in classical statistical mechanics is presented in a form parallel to the well known

Masatoshi Sato

A topological argument is presented for nodal structures of superconducting states with time-reversal invariance. A generic Hamiltonian which describes a quasiparticle in superconducting states with time-reversal invariance is derived, and it is shown that only line nodes are topologically stable in single-band descriptions of superconductivity. Using the ti

O. Pages, A. Chafi, D. Fristot, A. V. Postnikov

Contrary to a broadly accepted assumption we show that random (Ga,In)P is not an exception with respect to the crude classification of the phonon mode behavior of random mixed crystals in terms of 1-bond->1-mode systems or 2-bond->1-mode systems, as established from the simple criterion derived by Elliott et al. [Rev.Mod.Phys. 46, 465 (1974)]. Consistent und

Su-Chan Park, Hyunggyu Park

Crossover behaviors from the pair contact process with diffusion (PCPD) and the driven PCPD (DPCPD) to the directed percolation (DP) are studied in one dimension by introducing a single particle annihilation/branching dynamics. The crossover exponents $ϕ$ are estimated numerically as $1/ϕ\simeq 0.58\pm0.03$ for the PCPD and $1/ϕ\simeq 0.49 \pm 0.02$ for the

C. Cupelli, B. Henrich, M. Moseler, M. Santer

We demonstrate that Multi-Body Dissipative Particle Dynamics (MDPD) can be used as an efficient computational tool for the investigation of nanoscale capillary impregnation of confined geometries. As an essential prerequisite, a novel model for a solid-liquid interface in the framework of MDPD is introduced, with tunable wetting behaviour and thermal roughen

M. C. O. Aguiar, V. Dobrosavljevic, E. Abrahams, G. Kotliar

The scaling behavior of Anderson impurity models each of which with a different site energy epsilon_i is examined close to the Mott-Anderson transition. Depending on the impurity energy epsilon_i, in the critical regime the site turns into a local magnetic moment, as indicated by a vanishing quasiparticle weight Z -> 0, or remains nearly doubly occupied or n

F. M. Marchetti, J. Keeling, M. H. Szymanska, P. B. Littlewood

We study the thermodynamic condensation of microcavity polaritons using a realistic model of disorder in semiconductor quantum wells. This approach correctly describes the polariton inhomogeneous broadening in the low density limit, and treats scattering by disorder to all orders in the condensed regime. While the weak disorder changes the thermodynamic prop

L. Guzman, Y. Gomez, L. F. Rodriguez

We present high quality radio continuum observations made with the Very Large Array (VLA) at 3.6 cm at two epochs toward the planetary nebula M2-43. The comparison of the two epochs, obtained with a time separation of 4.07 years, clearly shows the expansion of the planetary nebula with an angular rate of 0.61 +/- 0.09 mas/year.Assuming that the expansion vel

Paolo Stellari

We prove that if two abelian varieties have equivalent derived categories then the derived categories of the smooth stacks associated to the corresponding Kummer varieties are equivalent as well. The second main result establishes necessary and sufficient conditions for the existence of equivalences between the twisted derived categories of two Kummer surfac

Theresia Eisenkölbl

We give another proof for the (-1)-enumeration of self-complementary plane partitions with at least one odd side-length by specializing a certain Schur function identity. The proof is analogous to Stanley&#39;s proof for the ordinary enumeration. In addition, we obtain enumerations of 180-degree symmetric rhombus tilings of hexagons with a barrier of arbitra

C. Voisin

We study a generalization of a conjecture made by Beauville on the Chow ring of hyper-Kähler algebraic varieties. Namely we prove in a number of cases that polynomial cohomological relations involving only CH^1(X) and the Chern classes of X are satisfied in CH(X). These cases are : punctual Hilbert schemes of a K3 surface S parameterizing subschemes of lengt

Lu-Xin Liu

The action of Weyl scale invariant p=2 brane which breaks the target super Weyl scale symmetry in the N=1, D=4 superspace down to the lower dimensional Weyl symmetry W(1,2) is derived by the approach of nonlinear realization. The dual form action for the Weyl scale invariant supersymmetric D2 brane is also constructed. The interactions of localized matter fi

Fu-Guo Deng, Xi-Han Li, Hong-Yu Zhou

An efficient high-capacity quantum secret sharing scheme is proposed following some ideas in quantum dense coding with two-photon entanglement. The message sender, Alice prepares and measures the two-photon entangled states, and the two agents, Bob and Charlie code their information on their photons with four local unitary operations, which makes this scheme

L. Mathey, D. -W. Wang

We study the quantum phase diagrams of Bose-Fermi mixtures of ultracold atoms confined to one dimension in an optical lattice. For systems with incommensurate densities, various quantum phases, e.g. charge/spin density waves, pairing, phase separation, and the Wigner crystal, are found to be dominant in different parameter regimes within a bosonization appro

Chengwu Zhang, Hongya Liu, Lixin Xu, P. S. Wesson

We use Wetterich&#39;s parameterization equation of state (EOS) of dark energy to a $5D$ Ricci-flat cosmological solution and we suppose the universe contains three major components: matter, radiation and dark energy. By using the relation between the scale factor and the redshift $z$, we show that the two arbitrary functions contained in the $5D$ solution c

K. S. Dawson, W. L. Holzapfel, J. E. Carlstrom, M. Joy

We report the final results of our study of the cosmic microwave background (CMB) with the BIMA array. Over 1000 hours of observation were dedicated to this project exploring CMB anisotropy on scales between 1&#39; and 2&#39; in eighteen 6.6&#39; FWHM fields. In the analysis of the CMB power spectrum, the visibility data is divided into two bins correspondin

Hiroaki Kanno

We establish a formula of the large N factorization of the modular S-matrix for the coupled representations in U(N) Chern-Simons theory. The formula was proposed by Aganagic, Neitzke and Vafa, based on computations involving the conifold transition. We present a more rigorous proof that relies on the universal character for rational representations and an ex

Guang Ping He

It was claimed that all quantum string seals are insecure [H. F. Chau, quant-ph/0602099]. However, here it will be shown that for imperfect quantum string seals, the information obtained by the measurement proposed in that reference is trivial. Therefore imperfect quantum string seals can be unconditionally secure.

Hsun-Hsien Chang

This report surveys quantum error-correcting codes. As Preskill claimed, 21st century would be the golden age of quantum error correction. Quantum channels behave differently from classical channels, so researchers face difficulties in developing robust quantum codes. Fortunately, the classical error control methods have been well developed. If we can learn

Fu-Guo Deng, Xi-Han Li, Hong-Yu Zhou, Zhan-jun Zhang

We analyzed the security of the multiparty quantum secret sharing (MQSS) protocol recently proposed by Zhang, Li and Man [Phys. Rev. A \textbf{71}, 044301 (2005)] and found that this protocol is secure for any other eavesdropper except for the agent Bob who prepares the quantum signals as he can attack the quantum communication with a Trojan horse. That is,

A. J. Scott

We investigate the performance of a quantum error-correcting code when pushed beyond its intended capacity to protect information against errors, presenting formulae for the probability of failure when the errors affect more qudits than that specified by the code&#39;s minimum distance. Such formulae provide a means to rank different codes of the same minimu

E. Calzavarini, C. R. Doering, J. D. Gibbon, D. Lohse

It is shown that homogeneous Rayleigh-Benard flow, i.e., Rayleigh-Benard turbulence with periodic boundary conditions in all directions and a volume forcing of the temperature field by a mean gradient, has a family of exact, exponentially growing, separable solutions of the full non-linear system of equations. These solutions are clearly manifest in numerica

Debra L. Machacek, Elizabeth A. Foreman, Q. E. Hoq, P. G. Kevrekidis

We introduce an inhomogeneously-nonlinear Schr{ö}dinger lattice, featuring a defocusing segment, a focusing segment and a transitional interface between the two. We illustrate that such inhomogeneous settings present vastly different dynamical behavior than the one expected in their homogeneous counterparts in the vicinity of the interface. We analyze the re

Alexander E. Hramov, Alexey A. Koronovskii, Vladimir I. Ponomarenko, Mikhail D. Prokhorov

We propose a method for detecting the presence of synchronization of self-sustained oscillator by external driving with linearly varying frequency. The method is based on a continuous wavelet transform of the signals of self-sustained oscillator and external force and allows one to distinguish the case of true synchronization from the case of spurious synchr

Arkadi Minkin

We expose the most advanced equiconvergence results for Birkhoff- and Stone-regular differential operators and present also author&#39;s approach to this problem. We give a full proof of equiconvergence on the whole interval, which constitutes a true generalization of the Tamarkin-Stone theorem.

Garret Sobczyk

The Euclidean Algorithm is the often forgotten key to rational approximation techniques, including Taylor, Lagrange, Hermite, osculating, cubic spline, Chebyshev, Pade and other interpolation schemes. A unified view of these various interpolation techniques is eloquently expressed in terms of the concept of the spectral basis of a factor ring of polynomials.

Dr. W. B. Vasantha Kandasamy, Dr. Florentin Smarandache

There are many fuzzy models like Fuzzy matrices, Fuzzy Cognitive Maps, Fuzzy relational Maps, Fuzzy Associative Memories, Bidirectional Associative memories and so on. But almost all these models can give only one sided solution like hidden pattern or a resultant output vector dependent on the input vector depending in the problem at hand. So for the first t

Hongjia Chen, Yun Gao, Shikui Shang

We use a fermionic extension of the bosonic module to obtain a class of B(0,N)-graded Lie superalgebras with nontrivial central extensions.

Hsiang-Ping Huang

For any finite dimensional C*-algebra A with any trace vector {\vec s} whose components are rational numbers, we give an endomorphism Φ of the hyperfinite II_1 factor R such that: forall k in {\mathbb N} Φ^k (R)&#39; \cap R= \otimes^k A The canonical trace τ on R extends the trace vector {\vec s} on A. As a corollary, we construct a one-parameter family of i

Stefan Friedl, Taehee Kim

Given a finitely presented group G and an epimorphism G to the group of integers Cochran and Harvey defined a sequence of integral invariants, which can be viewed as the degrees of higher--order Alexander polynomials. Cochran and Harvey showed that (up to a minor modification) this is a never decreasing sequence of numbers if G is the fundamental group of a

A. Tsurkov

One of the central questions of universal algebraic geometry is: when two algebras have the same algebraic geometry? There are various interpretations of the sentence &#34;Two algebras have the same algebraic geometry&#34;. One of these is automorphic equivalence of algebras, which is discussed in this paper, and the other interpretation is geometric equival

S. P. de Alwis

This is an account of lectures that were given at TASI 2005, the Shanghai Summer School in M-theory 2005 and the Perimeter Institute. I review 1) the derivation of the potential for chiral scalar fields in ${\cal N}$=1 supergravity 2) the relation between F and D terms for chiral scalars, Weyl anomalies and the generation of non-perturbative terms in the sup

Tamari~T. Khachidze, Anzor~A. Khelashvili

As is known, the so-called Dirac $K$-operator commutes with the Dirac Hamiltonian for arbitrary central potential $V(r)$. Therefore the spectrum is degenerate with respect to two signs of its eigenvalues. This degeneracy may be described by some operator, which anticommutes with $K$. If this operator commutes with the Dirac Hamiltonian at the same time, then

J. S. Valverde, M. Pazetti

We propose a SUSY variant of the action for a massless spinning particles via the inclusion of twistor variables. The action is constructed to be invariant under SUSY transformations and $τ$-reparametrizations even when an interaction field is including. The constraint analysis is achieved and the equations of motion are derived. The commutation relations ob

Kazuyuki Furuuchi

In the real time formulation of finite temperature field theories, one introduces an additional set of fields (type-2 fields) associated to each field in the original theory (type-1 field). In hep-th/0106112, in the context of the AdS-CFT correspondence, Maldacena interpreted type-2 fields as living on a boundary behind the black hole horizon. However, below

Pierre Fayet, Dan Hooper, Gunter Sigl

We show that light ($\simeq$ 1 -- 30 MeV) dark matter particles can play a significant role in core-collapse supernovae, if they have relatively large annihilation and scattering cross sections, as compared to neutrinos. We find that if such particles are lighter than $\simeq$ 10 MeV and reproduce the observed dark matter relic density, supernovae would cool

Wolfgang Häusler, Peter Hänggi

Dipolar interaction between the magnetic moments of electrons is studied as a source for electron spin decay in quantum dots or arrays of quantum dots. This magnetic interaction will govern spin decay, after other sources, such as the coupling to nuclear spins or spin orbit coupling, have been eliminated by a suitable sample design. Electron-electron (Coulom

Shu-Chiuan Chang, Robert Shrock

We calculate the partition function $Z(G,Q,v)$ of the $Q$-state Potts model exactly for strips of the square and triangular lattices of various widths $L_y$ and arbitrarily great lengths $L_x$, with a variety of boundary conditions, and with $Q$ and $v$ restricted to satisfy conditions corresponding to the ferromagnetic phase transition on the associated two

Jae-Seung Lee, A. K. Khitrin

Solid-state NMR technique for measureing distances between hetero-nuclei in static powder samples is described. It is based on a two-dimensional single-echo scheme enhanced with adiabatic cross-polarization. As an example, the results for intra-molecular distances in $α$-crystalline form of glycine are presented. The measured NMR distances ^13 C(2) - ^15 N a

J. Ahmad, M. Shizuya, M. Isobe, S. Alam

We report infrared reflectivity spectra for a new correlated cupric oxide system Sr2Cu(Re0.69Ca0.31)Oy with y ~ 0.6 at several temperatures ranging between 8 and 380 K. The reflectivity spectrum at 300 K comprises of several optical phonons. A couple of residual bands located around 315 and 653 cm-1 exhibit exceptionally large intensity as compared to the ot

A. Sarkar, P. Barat, P. Mukherjee, S. K. Bandyopadhyay

The scaling behavior of the Portevin-Le Chatelier (PLC) effect is studied by deforming a substitutional alloy, Al-2.5%Mg and an interstitial alloy, low carbon steel (0.15%C, 0.33%Mn, 0.04%P, 0.05%S, 0.15%Si and rest Iron) at room temperature for a wide range of strain rates. To reveal the exact scaling nature, the time series data of true stress vs. time, ob

Kevin S. Bedell, Hari P. Dahal

Using the Landau Fermi liquid theory we have discovered a new regime for the propagation of spin waves in a quasi-equilibrium spin systems. We have determined the dispersion relation for the transverse spin waves and found that one of the modes is gapless. The gapless mode corresponds to the precessional mode of the magnetization in a paramagnetic system in

S. M. Fazeli, K. Esfarjani, B. Tanatar

Recent thermodynamic measurements on two-dimensional (2D) electron systems have found diverging behavior in the magnetic susceptibility and appearance of ferromagnetism with decreasing electron density. The critical densities for these phenomena coincide with the metal-insulator transition recorded in transport measurements. Based on density functional calcu

Zenji Hiroi, Shigeki Yonezawa

The superconducting transition of the ?-pyrochlore oxide KOs2O6 with Tc = 9.60 K is studied by resistivity measurements under various magnetic fields using a high-quality single crystal. The reentrant behavior of superconductivity is observed near Tc in low magnetic fields below 2 T. The recovered resistance probably due to flux flow exhibits an anomalous an

J. de la Figuera, J. M. Puerta, J. I. Cerda, F. El Gabaly

While a perfect hcp (0001) surface has three-fold symmetry, the diffraction patterns commonly obtained are six-fold symmetric. This apparent change in symmetry occurs because on a stepped surface, the atomic layers on adjacent terraces are rotated by 180 degrees. Here we use a Low-Energy Electron Microscope to acquire the three-fold diffraction pattern from

Ricardo L. C. Ogando, Marcio A. G. Maia, Cristina Chiappini, Paulo S. S. Pellegrini

We present radial gradients of the Lick index Mg2 for 40 early-type galaxies. In plots of Grad(Mg2) versus mass indicators, such as log(sigma), the lower boundary of the points distribution may be populated by galaxies which predominantly formed by monolithic collapse. Galaxies showing flatter gradients at higher masses could represent objects which suffered

Roy Maartens

Recent observations provide strong evidence that the universe is accelerating. This confronts theory with a severe challenge. Explanations of the acceleration within the framework of general relativity are plagued by difficulties. General relativistic models require a &#34;dark energy&#34; field with effectively negative pressure. An alternative to dark ener

Misty C. Bentz, Bradley M. Peterson, Richard W. Pogge, Marianne Vestergaard

We have obtained high resolution images of the central regions of 14 reverberation-mapped active galactic nuclei (AGN) using the Hubble Space Telescope Advanced Camera for Surveys High Resolution Camera to account for host-galaxy starlight contamination of measured AGN luminosities. We measure the host-galaxy starlight contribution to the continuum luminosit

Michael B. Baer

A novel lossless source coding paradigm applies to problems of unreliable lossless channels with low bit rates, in which a vital message needs to be transmitted prior to termination of communications. This paradigm can be applied to Alfred Renyi&#39;s secondhand account of an ancient siege in which a spy was sent to scout the enemy but was captured. After es

R. A. Bayliss, C. B. Forest, M. D. Nornberg, E. J. Spence

The role of turbulence in current generation and self-excitation of magnetic fields has been studied in the geometry of a mechanically driven, spherical dynamo experiment, using a three dimensional numerical computation. A simple impeller model drives a flow which can generate a growing magnetic field, depending upon the magnetic Reynolds number, Rm, and the

A. Conley, G. Goldhaber, L. Wang, G. Aldering

We present measurements of Ω_m and Ω_Λ from a blind analysis of 21 high-redshift supernovae using a new technique (CMAGIC) for fitting the multi-color lightcurves of Type Ia supernovae, first introduced in Wang et al. (2003). CMAGIC takes advantage of the remarkably simple behavior of Type Ia supernovae on color-magnitude diagrams, and has several advantages

Gerald V. Dunne, Holger Gies, Christian Schubert, Qing-hai Wang

In a previous paper [1], it was shown that the worldline expression for the nonperturbative imaginary part of the QED effective action can be approximated by the contribution of a special closed classical path in Euclidean spacetime, known as a worldline instanton. Here we extend this formalism to compute also the prefactor arising from quantum fluctuations

Christian R. Scullard, Robert M. Ziff

Here we show how the recent exact determination of the bond percolation threshold for the martini lattice can be used to provide approximations to the unsolved kagomé and (3,12^2) lattices. We present two different methods, one of which provides an approximation to the inhomogeneous kagomé and (3,12^2) bond problems, and the other gives estimates of $p_c$ fo

M. Trenti, D. C. Heggie, P. Hut

[abridged] We extend our analysis of the dynamical evolution of simple star cluster models, in order to provide comparison standards that will aid in interpreting the results of more complex realistic simulations. We augment our previous primordial-binary simulations by introducing a tidal field, and starting with King models of different central concentrati

Christoph Lamm

We prove that all 2-bridge ribbon knots are symmetric unions.

Michael Eisermann, Christoph Lamm

We present an intriguing question about lattice points in triangles where Pick&#39;s formula is &#34;almost correct&#34;. The question has its origin in knot theory, but its statement is purely combinatorial. After more than 30 years the topological question was recently solved, but the lattice point problem is still open.

M. Doring, E. Oset, D. Strottman

We make a study of the (pi^- p --> K^0 pi^0 Lambda), (pi^+ p --> K^+ pi^+ Lambda), (K^+\bar{K}^0 p), (K^+ pi^+ Sigma^0), (K^+ pi^0 Sigma^+), and (eta pi^+ p) reactions, in which the basic dynamics is given by the excitation of the Delta^*(1700) resonance which subsequently decays into (K Sigma^*(1385)) or (Delta(1232) eta). In a similar way we also study the

Glenn Barnich, Maxim Grigoriev

We construct a first order parent field theory for free higher spin gauge fields on constant curvature spaces. As in the previously considered flat case, both Fronsdal&#39;s and Vasiliev&#39;s unfolded formulations can be reached by two different straightforward reductions. The parent theory itself is formulated using a higher dimensional embedding space and

Sandra Martinez, Noemi Wolanski

We consider the optimization problem of minimizing $\int_ΩG(|\nabla u|)+λχ_{\{u>0\}} dx$ in the class of functions $W^{1,G}(Ω)$ with $u-ϕ_0\in W_0^{1,G}(Ω)$, for a given $ϕ_0\geq 0$ and bounded. $W^{1,G}(Ω)$ is the class of weakly differentiable functions with $\int_ΩG(|\nabla u|) dx<\infty$. The conditions on the function G allow for a different behavior at

J. D. McEwen, P. Vielva, M. P. Hobson, E. Martinez-Gonzalez

Using a directional spherical wavelet analysis we detect the integrated Sachs-Wolfe (ISW) effect, indicated by a positive correlation between the first-year Wilkinson Microwave Anisotropy Probe (WMAP) and NRAO VLA Sky Survey (NVSS) data. Detections are made using both a directional extension of the spherical Mexican hat wavelet and the spherical butterfly wa

Daniel Arean, Alfonso V. Ramallo

We study systematically the open string modes of a general class of BPS intersections of branes. We work in the approximation in which one of the branes is considered as a probe embedded in the near-horizon geometry generated by the other type of branes. We mostly concentrate on the D3-D5 and D3-D3 intersections, which are dual to defect theories with a mass

Peter M. Woods, Chryssa Kouveliotou, Mark H. Finger, Ersin Gogus

On 2004 December 27, a highly-energetic giant flare was recorded from the magnetar candidate SGR 1806-20. In the months preceding this flare, the persistent X-ray emission from this object began to undergo significant changes. Here, we report on the evolution of key spectral and temporal parameters prior to and following this giant flare. Using the Rossi X-r

L. Borisov, A. Libgober

We show that elliptic classes introduced in our earlier paper for spaces with infinite fundamental groups yield Novikov&#39;s type higher elliptic genera which are invariants of K-equivalence. This include, as a special case, the birational invariance of higher Todd classes studied recently by J.Rosenberg and J.Block-S.Weinberger. We also prove the modular p

L. Benfatto, M. B. Silva Neto

We consider theoretically the effects of an applied uniform magnetic field on the magnetic spectrum of anisotropic two-dimensional and Dzyaloshinskii-Moriya layered quantum Heisenberg antiferromagnets. The first case is relevant for systems such as the two-dimensional square lattice antiferromagnet Sr(2)CuO(2)Cl(2), while the later is known to be relevant to

Martin Kunz, Roberto Trotta, David Parkinson

We introduce a statistical measure of the effective model complexity, called the Bayesian complexity. We demonstrate that the Bayesian complexity can be used to assess how many effective parameters a set of data can support and that it is a useful complement to the model likelihood (the evidence) in model selection questions. We apply this approach to recent

Rosanna Coviello, Francesco Russo

In this paper we discuss existence and uniqueness for a one-dimensional time inhomogeneous stochastic differential equation directed by an $\mathbb{F}$-semimartingale $M$ and a finite cubic variation process $ξ$ which has the structure $Q+R$, where $Q$ is a finite quadratic variation process and $R$ is strongly predictable in some technical sense: that condi

Brigitte Hiller, Alexander A. Osipov, Veronique Bernard, Alex H. Blin

Low energy hadron phenomenology involving the (u,d,s) quarks is often approached through effective multi-quark Lagrangians with the symmetries of QCD. A very successful approach consists in taking the four-quark Nambu--Jona-Lasinio Lagrangian with the chiral $U_L(3)\times U_R(3)$ symmetry in the massless limit, combined with the $U_\A(1)$ breaking six-quark

Filipe Paccetti Correia, Michael G. Schmidt, Zurab Tavartkiladze

We present a detailed study of the reduction to 4D of 5D supergravity compactified on the S^1/Z_2 orbifold. For this purpose we develop and employ a recently proposed N=1 conformal superfield description of the 5D supergravity couplings to abelian vector and hypermultiplets. In particular, we obtain a unique relation of the &#34;radion&#34; to chiral superfi

Boudewijn F. Roukema

Several analyses of the cosmic microwave background map made by the satellite WMAP suggest that the global shape of a spatial section of the Universe is that of a Poincare dodecahedral space. A summary of some of these analyses and a description of independent tests which should be able to either increase confidence in the hypothesis or else refute it to ext

David R. Bickel

Reacting against the limitation of statistics to decision procedures, R. A. Fisher proposed for inductive reasoning the use of the fiducial distribution, a parameter-space distribution of epistemological probability transferred directly from limiting relative frequencies rather than computed according to the Bayes update rule. The proposal is developed as fo

Richard Thomson, Alex Pang, Chueng-Ryong Ji

We present the results of calculations analyzing nucleon Compton scattering to lowest order using perturbative QCD (pQCD) methods. Two scenarios are considered: (1) the incoming photon is real; and (2) the incoming photon is virtual. The case of a real photon has been previously analyzed at least 5 times using pQCD, but no two results are in agreement. Here

Jeter Hall, Paolo Gondolo

Dark matter annihilation has been proposed to explain the TeV gamma rays observed from the Galactic Center. We study constraints on this hypothesis coming from the mass profile around the Galactic Center measured by observing stellar dynamics. We show that for current particle models, the constraints on the dark matter density profile from measurements of ma

Y. Brihaye, T. Delsate, B. Hartmann

We study a 6-dimensional brane world model with an abelian string residing in the two extra dimensions. We study both static as well as inflating branes and find analytic solutions for the case of trivial matter fields in the bulk. Next to singular space-times, we also find solutions which are regular including cigar-like universes as well as solutions with

Richard A. Klemm, Dmitri V. Efremov

We present a microscopic theory of single molecule magnets. From our exact single-ion spin matrix elements for four arbitrary spins, we study the single-ion anisotropy of equal spins exhibiting $T_d$, $D_{2d}$, or $C_{4v}$ molecular group symmetry. Each group generates site-dependent single-ion anisotropy. For weak anisotropy, accurate Hartree expressions fo