July 2005 arXiv papers — page 10

Michael Hermele, T. Senthil, Matthew P. A. Fisher

We study the properties of a class of two-dimensional interacting critical states -- dubbed algebraic spin liquids -- that can arise in two-dimensional quantum magnets. A particular example that we focus on is the staggered flux spin liquid, which plays a key role in some theories of underdoped cuprate superconductors. We show that the low-energy theory of s

C. Guidorzi, F. Frontera, E. Montanari, F. Rossi

We report test results of the correlation between time variability and peak luminosity of Gamma-Ray Bursts (GRBs), using a larger sample (32) of GRBs with known redshift than that available to Reichart et al. (2001), and using as variability measure that introduced by these authors. The results are puzzling. Assuming an isotropic-equivalent peak luminosity,

Kristen Gillmon, J. Michael Shull

We combine data from our recent FUSE survey of interstellar molecular hydrogen absorption toward 50 high-latitude AGN with COBE-corrected IRAS 100 micron emission maps to study the correlation of infrared cirrus with H2. A plot of the H2 column density vs. IR cirrus intensity shows the same transition in molecular fraction, f_H2, as seen with total hydrogen

Matthew Hansen, S. Peng Oh

Hydrogen Ly-alpha is our primary emission-line window into high redshift galaxies. Surprisingly, despite an extensive literature, Ly-alpha radiative transfer in the most realistic case of a dusty, multi-phase medium has not received detailed theoretical attention. We investigate resonant scattering through an ensemble of dusty, moving, optically thick gas cl

Brian J. Barris, John L. Tonry, Megan C. Novicki, W. Michael Wood-Vasey

We present a new method for optimally extracting point-source time variability information from a series of images. Differential photometry is generally best accomplished by subtracting two images separated in time, since this removes all constant objects in the field. By removing background sources such as the host galaxies of supernovae, such subtractions

Pavel Kroupa, Carsten Weidner

Theoretical considerations lead to the expectation that stars should not have masses larger than about m_{max*}=60-120Msun, while the observational evidence has been ambiguous. Only very recently has a physical stellar mass limit near 150Msun emerged thanks to modern high-resolution observations of local star-burst clusters. But this limit does not appear to

Kristen Gillmon, J. Michael Shull, Jason Tumlinson, Charles Danforth

We report results from a FUSE survey of interstellar molecular hydrogen (H2) along 45 sight lines to AGN at high Galactic latitudes (|b| > 20 degrees). Most (39 of 45) of the sight lines show detectable Galactic H2 absorption from Lyman and Werner bands between 1000 and 1126 A, with column densities ranging from N(H2) = 10^(14.17-19.82) cm^-2. In the norther

Paulo J. V. Garcia, Jean-Phillipe Berger, Romano Corradi, Thierry Forveille

VITRUV is a second generation spectro-imager for the PRIMA enabled Very Large Telescope Interferometer. By combining simultaneously up to 8 telescopes VITRUV makes the VLTI up to 6 times more efficient. This operational gain allows two novel scientific methodologies: 1) massive surveys of sizes; 2) routine interferometric imaging. The science cases presented

C. M. Hamilton, W. Herbst, F. J. Vrba, M. A. Ibrahimov

We present results from the most recent (2002-2004) observing campaigns of the eclipsing system KH 15D, in addition to re-reduced data obtained at Van Vleck Observatory (VVO) between 1995 and 2000. Phasing nine years of photometric data shows substantial evolution in the width and depth of the eclipses. The most recent data indicate that the eclipses are now

Margaret A. Livingstone, Victoria M. Kaspi, Fotis P. Gavriil

We present a new phase-coherent timing analysis for the young, energetic pulsar PSR B0540-69 using 7.6 yr of data from the Rossi X-Ray Timing Explorer. We measure the braking index, n=2.140+/-0.009, and discuss our measurement in the context of other discordant values reported in the literature. We present an improved source position from the phase-coherent

Stefan Westerhoff, Chad B. Finley

We present the results of a search for cosmic ray point sources at energies above 10^19 eV in the HiRes stereo data set. The analysis is based on a maximum likelihood ratio test using the probability density function for each event rather than requiring an a priori choice of a fixed angular bin size. The search is extended to the combined data set of HiRes d

M. Netopil, E. Paunzen, H. M. Maitzen, A. Claret

The first CCD photometric investigation of the open cluster NGC 7296 up to now was performed within the narrow band Delta a photometric system, which enables us to detect peculiar objects. A deeper investigation of that cluster followed, using the standard BVR-Bessel filter set. The age and E(B-V) was determined independently to log t= 8.0 and 0.15 respectiv

Jacco Th. van Loon, Jonathan R. Marshall, Albert A. Zijlstra

We present the results of an investigation of post-Main Sequence mass loss from stars in clusters in the Magellanic Clouds, based around an imaging survey in the L'-band (3.8 micron) performed with the VLT at ESO. The data are complemented with JHKs and mid-IR photometry. The goal is to determine the influence of initial metallicity and initial mass on t

Tom Theuns

The physical state of the intergalactic medium can be probed in great detail with the intervening absorption systems seen in quasar spectra. The properties of the Hydrogen absorbers depend on many cosmological parameters, such as the matter-power spectrum, reionisation history, ionising background and the nature of the dark matter. The spectra also contain m

R. K. Zamanov, M. F. Bode, C. H. F. Melo, J. Porter

We have measured the rotational velocities (v.sini) of the mass donors in a number of D'--type symbiotic stars, using the cross-correlation function method. Four from five D' symbiotic stars with known v.sini, appeared to be very fast rotators compared with the catalogues of v.sini for the corresponding spectral types. At least three of these stars r

Yoshiaki Sofue, Hiromitsu Kigure, Kazunari Shibata

We propose a new mechanism to explain the radio Arc and threads in the Galactic Center by current sheets produced by local magnetic shears due to interaction of a moving cloud and the vertical field based on three-dimensional magneto-hydrodynamical simulations. Magnetic reconnetion and acceleration of cosmic-ray electrons in the current sheet will result in

L. G. Althaus, E. García--Berro, J. Isern, A. H. Córsico

We present detailed theoretical mass-radius relations for massive white dwarf stars with oxygen-neon cores. This work is motivated by recent observational evidence about the existence of white dwarf stars with very high surface gravities. Our results are based on evolutionary calculations that take into account the chemical composition expected from the evol

Milos Milosavljevic, Ehud Nakar, Anatoly Spitkovsky

It is generally accepted that magnetic fields generated in the nonlinear development of the transverse Weibel instability provide effective collisionality in unmagnetized collisionless shocks. Recently, extensive two and three dimensional simulations improved our understanding of the growth and saturation of the instability in colliding plasma shells. Howeve

Hongsu Kim

In the present work, the Brans-Dicke (BD) theory of gravity is taken as a possible theory of k-essence. Then starting with the (already known) Brans-Dicke-Schwarzschild solution which can represent the gravitationally bound static configurations of the BD scalar k-essence, issues like whether these configurations can reproduce the observed properties of gala

S. Schanne, M. Casse, J. Paul, B. Cordier

The electron-positron annihilation source in the Galactic center region has recently been observed with INTEGRAL/SPI, which shows that this 511 keV source is strong and its extension is consistent with the Galactic bulge geometry. The positron production rate, estimated to more than 10$^{43}$ per second, is very high and raises a challenging question about t

José P. S. Lemos

We give a review of classical, thermodynamic and quantum properties of black holes relevant to fundamental physics.

M. Argyrou, A. Katsikatsou, I. Malamos

The one-loop effective potential is a powerful tool in studying the electroweak symmetry breaking of supersymmetric theories, whose precise calculation may have important phenomenological consequences. In this work, we are correctly treating the contribution of the Higgs sector to the effective potential and refine the radiative corrections to the Higgs mixi

Ioannis Raptis

Previous work on applications of Abstract Differential Geometry (ADG) to discrete Lorentzian quantum gravity is brought to its categorical climax by organizing the curved finitary spacetime sheaves of quantum causal sets involved therein, on which a finitary (:locally finite), singularity-free, background manifold independent and geometrically prequantized v

R. Lefevere, A. Schenkel

We consider a chain of coupled and strongly pinned anharmonic oscillators subject to a non-equilibrium random forcing. Assuming that the stationary state is approximately Gaussian, we first derive a stationary Boltzmann equation. By localizing the involved resonances, we next invert the linearized collision operator and compute the heat conductivity. In part

Sanjib Sharma, Matthias Steinmetz

We present a method to numerically estimate the densities of a discretely sampled data based on binary space partitioning tree. We start with a root node containing all the particles and then recursively divide each node into two nodes each containing roughly equal number of particles,until each of the nodes contains only one particle. The volume of such a l

Kae Nemoto, W. J. Munro

In this paper we investigate the linear and nonlinear models of optical quantum computation and discuss their scalability and efficiency. We show how there are significantly different scaling properties in single photon computation when weak cross-Kerr nonlinearities are allowed to supplement the usual linear optical set. In particular we show how quantum no

G. Vijaya Prakash, Rahul Singh, Ashwani Kumar, Rashmish K. Mishra

We demonstrate here a method to fabricate CdSe photonic crystal from a very cheap fabrication route of templated self-assembly. The hexagonal close-packed photonic crystals are formed by the electrochemical growth of CdSe through the interstitial spaces between polymer nano/micro sphere templates. The confocal voids containing photonic crystals can be made e

Hua Feng, Philip Kaaret

We examined X-ray spectral and timing properties of ultraluminous X-ray sources (ULXs) in nearby galaxies in XMM-Newton archival data. There appear to be three distinct classes of spectra. One class shows emission from hot, diffuse plasma. This thermal emission is similar to that seen from recent supernovae; the temperatures are in the range 0.6-0.8 keV and

Guy F. de Teramond, Stanley J. Brodsky

The AdS/CFT correspondence is a powerful tool to study the properties of conformal QCD at strong coupling in terms of a higher dimensional dual gravity theory. The power-law falloff of scattering amplitudes in the non-perturbative regime and calculable hadron spectra follow from holographic models dual to QCD with conformal behavior at short distances and co

P. S. Marrocchesi, H. S. Ahn, M. G. Bagliesi, A. Basti

CREAM (Cosmic Ray Energetics And Mass) is a multi-flight balloon mission designed to collect direct data on the elemental composition and individual energy spectra of cosmic rays. Two instrument suites have been built to be flown alternately on a yearly base. The tungsten/Sci-Fi imaging calorimeter for the second flight, scheduled for December 2005, was cali

J. C. Pei, F. R. Xu, P. D. Stevenson

We employed the Skyrme-Hartree-Fock model to investigate the density distributions and their dependence on nuclear shapes and isospins in the superheavy mass region. Different Skyrme forces were used for the calculations with a special comparison to the experimental data in $^{208}$Pb. The ground-state deformations, nuclear radii, neutron skin thicknesses an

Andrey A. Sukhorukov

We describe wave propagation and soliton localization in photonic lattices which are induced in a nonlinear medium by an optical interference pattern, taking into account the inherent lattice deformations at the soliton location. We obtain exact analytical solutions and identify the key factors defining soliton mobility, including the effects of gap merging

Christian Haase, Benjamin Nill

Lattices generated by lattice points in skeletons of reflexive polytopes are essential in determining the fundamental group and integral cohomology of Calabi-Yau hypersurfaces. Here we prove that the lattice generated by all lattice points in a reflexive polytope is already generated by lattice points in codimension two faces. This answers a question of J. M

Ira M. Gessel, Seunghyun Seo

A proper vertex of a rooted tree with totally ordered vertices is a vertex that is less than all its proper descendants. We count several kinds of labeled rooted trees and forests by the number of proper vertices. Our results are all expressed in terms of the polynomials P_n(a,b,c)= c(a+(n-1)b+c)(2a+(n-2)b+c)...((n-1)a+b+c) which reduce to (n+1)^{n-1} for a=

Venkata Balaji Thiruvalloor Eesanaipaadi

We describe a satisfactory theory of degeneration of quadratic forms in three variables in the most general setting possible: the quadratic forms are defined on rank 3 vector bundles over an arbitrary scheme and could have values in nontrivial line bundles. Our results extend what is known for good forms; for example we show that the Witt-invariant suffices

P. Baxendale, P. Chigansky, R. Liptser

Stability problem of the Wonham filter with respect to initial conditions is addressed. The case of ergodic signals is revisited in view of a gap in the classic work of H. Kunita (1971). We give new bounds for the exponential stability rates, which do not depend on the observations. In the non-ergodic case, the stability is implied by identifiability conditi

Yu-Xiao Liu, Li-Jie Zhang, Ji-Rong Ren

It has been shown that certain W algebras can be linearized by the inclusion of a spin-1 current. This Provides a way of obtaining new realizations of the W algebras. In this paper, we investigate the new ghost field realizations of the W(2,s)(s=3,4) algebras, making use of the fact that these two algebras can be linearized. We then construct the nilpotent B

Shyamoli Chaudhuri

We explain the motivation and main ideas underlying our proposal for a Lagrangian for Matrix Theory based on sixteen supercharges. Starting with the pedagogical example of a bosonic matrix theory we describe the appearance of a continuum spacetime geometry from a discrete, and noncommutative, spacetime with both Lorentz and Yang-Mills invariances. We explain

Shyamoli Chaudhuri

We develop new tools for an in-depth study of our recent proposal for Matrix Theory. We construct the anomaly-free and finite planar continuum limit of the ground state with SO(2^{13}) symmetry matching with the tadpole and tachyon free IR stable high temperature ground state of the open and closed bosonic string. The correspondence between large N limits an

B. Aubert, BABAR Collaboration

We present a study of the dynamics in B0 --> K+ K- K0S decays with approximately 230 million BBbar events collected by the BABAR detector at SLAC. We find that the Dalitz plot distribution is best parameterized with the phi K0S mode, an S-wave K+ K- resonance near 1500 MeV/c^2, and a large non-resonant contribution. We set limits on resonances not included i

Masaru Shibata, José A. Font

A recent paper by Lucas-Serrano et al. indicates that a high-resolution central (HRC) scheme is robust enough to yield accurate hydrodynamical simulations of special relativistic flows in the presence of ultrarelativistic speeds and strong shock waves. In this paper we apply this scheme in full general relativity (involving {\it dynamical} spacetimes), and a

Andre Adrian

What is Software Architecture? The rules, paradigmen, pattern that help to construct, build and test a serious piece of software. It is the practical experience boiled down to abstract level. Software Architecture builds on System Engineering and the scientific method as established by Galileo Galilei: Measure what you can and make measureable what you can n

S. Das Sarma, E. H. Hwang

The temperature dependence of 2D magnetoresistance in an applied in-plane magnetic field is theoretically considered for electrons in Si MOSFETs within the screening theory for long-range charged impurity scattering limited carrier transport. In agreement with recent experimental observations we find an essentially temperature independent magnetoresistivity

Aditi Mallik, Keith Runge, James W. Dufty, Hai-Ping Cheng

The approximate representation of a quantum solid as an equivalent composite semi-classical solid is considered for insulating materials. The composite is comprised of point ions moving on a potential energy surface. In the classical bulk domain this potential energy is represented by pair potentials constructed to give the same structure and elastic propert

Noam Gross, Einat Klein, Michael Rosenbluh, Wolfgang Kinzel

Two mutually coupled chaotic diode lasers with individual external feedback, are shown to establish chaos synchronization in the low-frequency fluctuations regime. A third laser with identical external feedback but coupled unidirectionally to one of the pair does not synchronize. Both experiments and simulations reveal the existence of a window of parameters

F. Heitsch, A. Burkert, L. Hartmann, A. D. Slyz

Molecular clouds (MCs) are highly structured and ``turbulent''. Colliding gas streams of atomic hydrogen have been suggested as a possible source of MCs, imprinting the filamentary structure as a consequence of dynamical and thermal instabilities. We present a 2D numerical analysis of MC formation via converging HI flows. Even with modest flow speeds

E. Athanassoula, J. C. Lambert, W. Dehnen

We study the effect of a central mass concentration (CMC) on the secular evolution of a barred disc galaxy. Unlike previous studies, we use fully self-consistent 3D $N$-body simulations with live haloes, which are known to be important for bar evolution. The CMC is introduced gradually, to avoid transients. In all cases where the mass of the CMC is of the or

W. Bednarek

Massive Wolf-Rayet stars in a compact binary systems are characterised by very strong winds which collide creating a shock wave. If the wind nuclei accelerated at the shock can reach large enough energies, they suffer disintegration in collisions with soft thermal radiation from the massive stars injecting relativistic protons and neutrons. Protons collide w

E. Paunzen, O. I. Pintado, H. M. Maitzen, A. Claret

With the aim to corroborate the result of a search for chemically peculiar stars in the Large Magellanic Cloud (LMC) we present measurements obtained from CCD-imaging of two fields, one containing a young open cluster (NGC 1711). While for the latter field, including its surrounding we obtain a contribution of three percent of chemically peculiar stars detec

Mohsen Shadmehri, Fazeleh Khajenabi

Thermal conduction has been suggested as a possible mechanism by which sufficient extra heating is provided in radiation-dominated accretion flows. We consider the extreme case in which the generated energy due to the viscosity and the energy transported by a saturated form of thermal conduction are balanced by the advection cooling. For the steady-state str

Angelo Carollo, Marcelo Franca Santos, Vlatko Vedral

We show that in the limit of strongly interacting environment a system initially prepared in a Decoherence Free Subspace (DFS) coherently evolves in time, adiabatically following the changes of the DFS. If the reservoir cyclicly evolves in time, the DFS states acquire an holonomy.

Anthonie W. J. Muller, Dirk Schulze-Makuch

The name 'sorption heat engines' is proposed for simple negative entropy generators that are driven by thermal cycling and work on alternating adsorption and desorption. These generators are in general not explicitly recognized as heat engines. Their mechanism is applicable to the fields of engineering, physics, chemistry, geology, and biology, in pa

Michele Della Morte, Roland Hoffmann, Francesco Knechtli, Juri Rolf

The running of renormalized quark masses is computed in lattice QCD with two flavors of massless O(a) improved Wilson quarks. The regularization and flavor independent factor that relates running quark masses to the renormalization group invariant ones is evaluated in the Schroedinger Functional scheme. Using existing data for the scale r_0 and the pseudosca

Sergej Y. Savrasov, Kristjan Haule, Gabriel Kotliar

We report computer based simulations of energetics, spectroscopy and electron-phonon interaction of americium using a novel spectral density functional method. This approach gives rise to a new concept of a many-body electronic structure and reveals the unexpected mixed valence regime of Am 5f6 electrons which under pressure acquire the 5f7 valence state. Th

F. Ardalan, H. Arfaei, N. Sadooghi

Invariant (nonplanar) anomaly of noncommutative QED is reexamined. It is found that just as in ordinary gauge theory UV regularization is needed to discover anomalies, in noncommutative case, in addition, an IR regularization is also required to exhibit existence of invariant anomaly. Thus resolving the controversy in the value of invariant anomaly, an expre

Alon E. Faraggi

E6 grand unification combines the Standard Model matter and Higgs states in the single 27 representation. I discuss how the E6 structure underlies the quasi-realistic free fermion heterotic-string models. E6 -> SO(10) X U(1) breaking is obtained by a GSO phase in the N=1 partition function. The equivalence of this symmetry breaking phase with a particular ch

Jing-Ling Chen, Chunfeng Wu, L. C. Kwek, C. H. Oh

We investigate the maximal violation of Bell inequalities for two $d$-dimensional systems by using the method of Bell operator. The maximal violation corresponds to the maximal eigenvalue of the Bell operator matrix. The eigenvectors corresponding to these eigenvalues are described by asymmetric entangled states. We estimate the maximum value of the eigenval

Xian-Ting Liang

In this paper we investigate a open two-qubit model whose dynamics is not exactly solvable. When the initial state is the maximum entangled state, as the exactly solvable open two-qubit model [D. Tolkunov and V. Privman, Phys. Rev. A 71, 060308(R) (2005)], the decay of entanglement of formation of the model, expressed by concurrence is also governed by the p

L. Li, Y. Meurice

We revisit the question of the convergence of lattice perturbation theory for a pure SU(3) lattice gauge theory in 4 dimensions. Using a series for the average plaquette up to order 10 in the weak coupling parameter beta^{-1}, we show that the analysis of the extrapolated ratio and the extrapolated slope suggests the possibility of a non-analytical power beh

Tao Huang, Cong-Feng Qiao, Xing-Gang Wu

The B-meson light-cone wavefunctions, $Ψ_{\pm}(ω,z^2)$, are investigated up to the next-to-leading order in Fock state expansion in the heavy quark limit. In order to know the transverse momentum dependence of the B-meson wavefunctions with 3-particle Fock states' contributions, we make use of the relations between 2- and 3- particle wavefunctions derive

Morteza Ahmadi, Saurya Das, S. Shankaranarayanan

It is known that the entanglement entropy of a scalar field, found by tracing over its degrees of freedom inside a sphere of radius ${\cal R}$, is proportional to the area of the sphere (and not its volume). This suggests that the origin of black hole entropy, also proportional to its horizon area, may lie in the entanglement between the degrees of freedom i

B. Geyer, G. L. Klimchitskaya, V. M. Mostepanenko

The Casimir interaction between two thick parallel plates, one made of metal and the other of dielectric, is investigated at nonzero temperature. It is shown that in some temperature intervals the Casimir pressure and the free energy of a fluctuating field are the nonmonotonous functions of temperature and the respective Casimir entropy can be negative. The

Hyuk-jae Lee, Sung Dahm Oh, Doyeol Ahn

We present an entanglement criterion for multiqubits by using the quantum correlation tensors which rely on the expectation values of the Pauli operators for a multiqubit state. Our criterion explains not only the total entanglement of the system but also the partial entanglement in subsystems. It shows that we have to consider the subsystem entanglements in

Etera R. Livine, Daniel R. Terno

We calculate the entanglement of formation and the entanglement of distillation for arbitrary mixtures of the zero spin states on an arbitrary-dimensional bipartite Hilbert space. Such states are relevant to quantum black holes and to decoherence-free subspaces based communication. The two measures of entanglement are equal and scale logarithmically with the

A. Ludu, N. Hutchings

We develop a formalism that describes the bending and twisting of axoneme-like filament bundles. We obtain general formulas to determine the relative sliding between any arbitrary filaments in a bundle subjected to unconstrained deformations. Particular examples for bending, twisting, helical and toroidal shapes, and combinations of these are discussed. Resu

Gordon Chalmers

A characterization of instanton contributions to gauge field theory is given. The dynamics of instantons with the gluon field is given in terms of 'classical' instanton contributions, i.e. on the same footing as tree amplitudes in field theory. This paramaterization depends on the kinematics of the local instanton operators and their coupling depende

P. G. Kevrekidis, D. J. Frantzeskakis, R. Carretero-Gonzalez, B. A. Malomed

We consider effects of anisotropy on solitons of various types in two-dimensional nonlinear lattices, using the discrete nonlinear Schr{ö}dinger equation as a paradigm model. For fundamental solitons, we develop a variational approximation, which predicts that broad quasi-continuum solitons are unstable, while their strongly anisotropic counterparts are stab

Lieven Le Bruyn, Stijn Symens

Let X be a singular affine normal variety with coordinate ring R and assume that there is an R-order admitting a stability structure such that the scheme of relevant semistable representations is smooth, then we construct a partial desingularization of X with classifiable remaining singularities. In dimension 3 this explains the omnipresence of conifold sing

Norio Iwase, Akira Kono

Let G be a compact connected Lie group and p : E \to Σ^2V a principal G-bundle with a characteristic map α: A=ΣV \to G. By combining cone decomposition arguments in Iwase-Mimura-Nishimoto [3,5] with computations of higher Hopf invariants introduced in Iwase [8], we generalize the result in Iwase-Mimura [12]: Let {F_{i}|0 \leq i \leq m} be a cone-decompositio

Yoe Itokawa, Ryoichi Kobayashi

We give a metric characterization of the Euclidean sphere in terms of the lower bound of the sectional curvature and the length of the shortest closed geodesics.

Abdelmalek Abdesselam, Jaydeep Chipalkatti

For generic binary forms $A_1,...,A_r$ of order $d$ we construct a class of combinants $C = \{\C_q: 0 \le q \le r, q \neq 1\}$, to be called the Wronskian combinants of the $A_i$. We show that the collection $C$ gives a projective imbedding of the Grassmannian $G(r,S_d)$, and as a corollary, any other combinant admits a formula as an iterated transvectant in

Hiroki Matui

Giordano, Putnam and Skau showed that topological full groups of Cantor minimal systems are complete invariants for flip conjugacy. We will completely determine the structure of normal subgroups of the topological full group. Moreover, a necessary and sufficient condition for the topological full group to be finitely generated will be given.

Janez Mrcun

We show that for any smooth Hausdorff manifolds M and N, which are not necessarily second countable, paracompact or connected, any isomorphism from the algebra of smooth (real or complex) functions on N to the algebra of smooth functions on M is given by composition with a unique diffeomorphism from M to N. An analogous result holds true for isomorphisms of

M. O. Tahim, C. A. S. Almeida

In this work we obtain topological and dual theories on brane-worlds in several dimensions. Our brane is a solitonic-like hypersurface embedded in a space-time with a specific dimensionality and it appears due to the breaking of a Peccei-Quinn-like symmetry. In the first part of this work, the obtained topological theories are related to a generalization of

Mohamed Chabab, Latifa Sanhaji

Following a recently proposed confinement generating mechanism, we provide a new string inspired model with a massive dilaton and a new dilaton coupling function [5]. By solving analytically the equations of motion, a new class of confining interquark potentials is derived which includes several popular potential forms given in the literature.

Dionisio Bazeia

This work contains a set of lectures on defect structures, mainly in models described by scalar fields in diverse dimensions.

F. Loran, E. Bavarsad

Studying the critical scalar theory in four dimensional Euclidean space with the potential term $-gϕ^4$ we show that the theory can not be analytically continued through g=0 from g<0 region to g>0 region. For g>0 although energy is not bounded from below but there exist a classical trajectory with an AdS5 moduli space, corresponding to a metastable local min

Andrew Neitzke, Cumrun Vafa

We give an introductory review of topological strings and their application to various aspects of superstrings and supersymmetric gauge theories. This review includes developing the necessary mathematical background for topological strings, such as the notions of Calabi-Yau manifold and toric geometry, as well as physical methods developed for solving them,

P. P. Avelino, C. J. A. P. Martins, J. C. R. E. Oliveira

We introduce a new phenomenological one-scale model for the evolution of domain wall networks, and test it against high-resolution field theory numerical simulations. We argue that previous numerical estimates of wall velocities are inaccurate, and suggest a more accurate method of measurement. We show that the model provides an adequate approximation to the

Shinya Kanemura, Yasuhiro Okada, Eibun Senaha

We study collider signatures of electroweak baryogenesis in the two Higgs doublet model and the minimal supersymmetric standard model. It is found that the trilinear coupling of the lightest Higgs boson receives large quantum corrections if the electroweak phase transition is strongly first order for successful baryogenesis. In the two Higgs doublet model, t

Pablo Galan, Guillermo A. Mena Marugan

It is commonly accepted that the combination of quantum mechanics and general relativity gives rise to the emergence of a minimum uncertainty both in space and time. The arguments that support this conclusion are mainly based on perturbative approaches to the quantization, in which the gravitational interactions of the matter content are described as correct

Steven D. Penn, Alexander Ageev, Dan Busby, Gregory M. Harry

We have compiled measurements of the mechanical loss in fused silica from samples spanning a wide range of geometries and resonant frequency in order to model the known variation of the loss with frequency and surface-to-volume ratio. This improved understanding of the mechanical loss has contributed significantly to the design of advanced interferometric gr

Muraari Vasudevan, Kory A. Stevens

We study the Hamilton-Jacobi and massive Klein-Gordon equations in the general Kerr-(Anti) de Sitter black hole background in all dimensions. Complete separation of both equations is carried out in cases when there are two sets of equal black hole rotation parameters. We analyze explicitly the symmetry properties of these backgrounds that allow for this Liou

O. Zuk, I. Kanter, E. Domany

The entropy of a binary symmetric Hidden Markov Process is calculated as an expansion in the noise parameter epsilon. We map the problem onto a one-dimensional Ising model in a large field of random signs and calculate the expansion coefficients up to second order in epsilon. Using a conjecture we extend the calculation to 11th order and discuss the converge

Todd M. Squires

Active microrheology differs from its passive counterpart in that the probe is actively forced through the material, rather than allowed to diffuse. Unlike in passive microrheology, active forcing allows the material to be driven out of equilibrium, and its nonlinear response to be probed. However, this also renders inoperable the fluctuation-dissipation the

N. Seferoglu, A. Ozkan, B. Kutlu

The first order phase transition of the three-dimensional Blume Capel are investigated using cooling algorithm which improved from Creutz Cellular Automaton for the $D/J=2.9$ parameter value in the first order phase transition region. The analysis of the data using the finite-size effect and the histogram technique indicate that the magnetic susceptibility m

Takahiro Yamamoto, Kazuyuki Watanabe, Satoshi Watanabe

The effect of molecular vibrations on electronic transport is investigated with the smallest fullerene C20 bridge, utilizing the Keldysh nonequilibrium Green&#39;s function techniques combined with the tight-binding molecular-dynamics method. Large discontinuous steps appear in the differential conductance when the applied bias-voltage matches particular vib

C. S. O&#39;Hern, L. E. Silbert, A. J. Liu, S. R. Nagel

We answer the questions raised by Donev, Torquato, Stillinger, and Connelly in their &#34;Comment on &#34;Jamming at zero temperature and zero applied stress: The epitome of disorder.&#39; &#34; We emphasize that we follow a fundamentally different approach than they have done to reinterpret random close packing in terms of the &#34;maximally random jammed&#

H. J. Xiang, W. Z. Liang, Jinlong Yang, J. G. Hou

We present an extension of density matrix based linear scaling electronic structure theory to incorporate spin degrees of freedom. When the spin multiplicity of the system can be predetermined, the generalization of the existing linear scaling methods to spin unrestricted cases is straightforward. However, without calculations it is hard to determine the spi

Martin Eckstein, Marcus Kollar, Krzysztof Byczuk, Dieter Vollhardt

We derive an operator identity which relates tight-binding Hamiltonians with arbitrary hopping on the Bethe lattice to the Hamiltonian with nearest-neighbor hopping. This provides an exact expression for the density of states (DOS) of a non-interacting quantum-mechanical particle for any hopping. We present analytic results for the DOS corresponding to hoppi

Priya Jamkhedkar, Long-Long Feng, Wei Zheng, Li-Zhi Fang

We have studied the power spectrum and the intermittent behavior of the fluctuations in the transmitted flux of HE2347-4342 ${\rm Ly}α$ absorption in order to investigate if there is any discrepancy between the LCDM model with parameters given by the WMAP and observations on small scales. If the non-Gaussianity of cosmic mass field is assumed to come only fr

M. E. Gusakov, A. D. Kaminker, D. G. Yakovlev, O. Y. Gnedin

We study the cooling of superfluid neutron stars whose cores consist of nucleon matter with the Akmal-Pandharipande-Ravenhall equation of state. This equation of state opens the powerful direct Urca process of neutrino emission in the interior of most massive neutron stars. Extending our previous studies (Gusakov et al. 2004a, Kaminker et al. 2005), we emplo

Maxim Lyutikov, Fotis P. Gavriil

Resonant cyclotron scattering of the surface radiation in the magnetospheres of neutron stars may considerably modify the emergent spectra and impede efforts to constraint neutron star properties. Resonant cyclotron scattering by a non-relativistic warm plasma in an inhomogeneous magnetic field has a number of unusual characteristics: (i) in the limit of hig

Tomaso Belloni

Due to the impressive amount of new data provided by the RXTE satellite in the past decade, our knowledge of the phenomenology of accretion onto black holes has increased considerably. In particular, it has been possible to schematize the outburst evolution of transient systems on the basis of their spectral and timing properties, and link them to the ejecti

P. A. Sharma, N. Harrison, M. Jaime, Y. S. Oh

A dramatic increase in the total thermal conductivity (k) is observed in the Hidden Order (HO) state of single crystal URu2Si2. Through measurements of the thermal Hall conductivity, we explicitly show that the electronic contribution to k is extremely small, so that this large increase in k is dominated by phonon conduction. An itinerant BCS/mean-field mode

Jacob D. Stevenson, Joerg Schmalian, Peter G. Wolynes

The shapes of cooperatively rearranging regions in glassy liquids change from being compact at low temperatures to fractal or ``stringy&#39;&#39; as the dynamical crossover temperature from activated to collisional transport is approached from below. We present a quantitative microscopic treatment of this change of morphology within the framework of the rand

Mark Alford, Qing-hai Wang

We calculate secondary pairing in a model of a color superconductor with a quadratic gapless dispersion relation for the quasiquarks of the primary pairing. Our model mimics the physics of the sector of blue up and red strange quarks in gapless color-flavor-locked quark matter. The secondary pairing opens up a gap Delta_s in the quark spectrum, and we confir

A. Zaniewski, Geoffrey C. Clayton, D. L. Welch, Karl D. Gordon

We have identified five new R Coronae Borealis (RCB) stars in the Galactic bulge using the MACHO Project photometry database, raising the total number of known Galactic RCB stars to about 40. We have obtained spectra to confirm the identifications. The fact that four out of the five newly identified RCB stars are ``cool&#39;&#39; (T(eff) < 6000 K) rather tha

J. Casares, M. Ribo, I. Ribas, J. M. Paredes

The population of high energy and very high energy gamma-ray sources, detected with EGRET and the new generation of ground-based Cherenkov telescopes, conforms a reduced but physically important sample. Most of these sources are extragalactic (e.g., blazars), while among the galactic ones there are pulsars and SN remnants. The microquasar LS 5039, previously

Nicholas M Ball, Jon Loveday, Robert J Brunner, Ivan K Baldry

Bivariate luminosity functions (LFs) are computed for galaxies in the New York Value-Added Galaxy Catalogue, based on the Sloan Digital Sky Survey Data Release 4. The galaxy properties investigated are the morphological type, inverse concentration index, Sersic index, absolute effective surface brightness, reference frame colours, absolute radius, eClass spe