June 2007 arXiv papers — page 33

Jeremy Bailin, Chris Power, Peder Norberg, Dennis Zaritsky

We identify satellites of isolated galaxies in SDSS and examine their angular distribution. Using mock catalogues generated from cosmological N-body simulations, we demonstrate that the selection criteria used to select isolated galaxies and their satellites must be very strict in order to correctly identify systems in which the primary galaxy dominates its

M. V. Ioffe, J. Mateos Guilarte, P. A. Valinevich

The supersymmetrical approach is used to analyse a class of two-dimensional quantum systems with periodic potentials. In particular, the method of SUSY-separation of variables allowed us to find a part of the energy spectra and the corresponding wave functions (partial solvability) for several models. These models are not amenable to conventional separation

D. V. Bugg

Claims have been made that f0(1370) does not exist. The five primary sets of data requiring its existence are refitted. Major dispersive effects due to the opening of the 4pi threshold are included for the first time; the sigma -> 4pi amplitude plays a strong role. Crystal Barrel data on pbar-p -> 3pizero at rest require f0(1370) signals of at least 32 and 3

Rafael D. Vilela, Adilson E. Motter

The fate of aerosols in open flows is relevant in a variety of physical contexts. Previous results are consistent with the assumption that such finite-size particles always escape in open chaotic advection. Here we show that a different behavior is possible. We analyze the dynamics of aerosols both in the absence and presence of gravitational effects, and bo

Takayuki Tatekawa, Shuntaro Mizuno

We explore the initial conditions for cosmological N-body simulations suitable for calculating the skewness and kurtosis of the density field. In general, the initial conditions based on the perturbation theory (PT) provide incorrect second-order and higher-order growth. These errors implied by the use of the perturbation theory to set up the initial conditi

Konstantinos Drakakis, Scott Rickard

We extend the definition of the Costas property to functions in the continuum, namely on intervals of the reals or the rationals, and argue that such functions can be used in the same applications as discrete Costas arrays. We construct Costas bijections in the real continuum within the class of piecewise continuously differentiable functions, but our attemp

C. G. Bollini, M. C. Rocca

In this paper we show that Ultradistributions of Exponential Type (UET) are appropriate for the description in a consistent way string and string field theories. A new Lagrangian for the closed string is obtained and shown to be equivalent to Nambu-Goto's Lagrangian. We also show that the string field is a linear superposition of UET of compact support C

W. K. Park, H. Stalzer, J. L. Sarrao, J. D. Thompson

Our previous point-contact Andreev reflection studies of the heavy-fermion superconductor CeCoIn$_5$ using Au tips have shown two clear features: reduced Andreev signal and asymmetric background conductance [1]. To explore their physical origins, we have extended our measurements to point-contact junctions between single crystalline heavy-fermion metals and

M. Abdelwahab, S Carloni, P K. S. Dunsby

We present a detailed investigation of the cosmological dynamics based on $\exp (-R/Λ)$ gravity. We apply the dynamical system approach to both the vacuum and matter cases and obtain exact solutions and their stability in the finite and asymptotic regimes. The results show that cosmic histories exist which admit a double de-Sitter phase which could be useful

Joern Wilms, Katja Pottschmidt, Guy G. Pooley, Sera Markoff

We report on the first detection of a quasi-simultaneous radio-X-ray flare of Cygnus X-1. The detection was made on 2005 April 16 with pointed observations by the Rossi X-ray Timing Explorer and the Ryle telescope, during a phase where the black hole candidate was close to a transition from the its soft into its hard state. The radio flare lagged the X-rays

M. E. Povarnitsyn, T. E. Itina, M. Sentis, K. V. Khishchenko

A numerical hydrodynamic study of femtosecond laser ablation is presented. A detailed analysis of material decomposition is performed using a thermodynamically complete equation of state with separate stable and metastable phase states and phase boundaries. The lifetime of the metastable liquid state is estimated based on the classical theory of homogeneous

Ulrich H. P. Fischer, Michael Schmidt, Tino Volmer, Bjoern Weigl

The demand for high-speed digital communication such as data, video, and the broadband Internet increases, the required throughput of the modules in communications systems will also increase. In this paper we present an instruction system, which works on the basis of a wavelength division multiplex (WDM) system in the visible spectrum. It is specialised for

Ulrich H. P. Fischer, Thomas Windel

In this paper a new method for spotsize-measurement for singlemode optical components is presented. Based from the classical farfield-method where the measurements are made circular, the mounting of the used rotary stages and the long measurement time are great disadvantages. In this paper a new planar method is described which overcomes these problems. Base

Jesus Inarrea

We analyzed the magnetoresistivity of a two-dimensional electron system excited by microwave radiation in a regime of high intensities and low frequencies. In such a regime, recent experiments show that different features appear in the magnetoresistivity response which suggest an anharmonic behavior. These features consist mainly in distorted oscillations an

Ulysse Serres

The goal of this paper is to describe Zermelo's navigation problem on Riemannian manifolds as a time-optimal control problem and give an efficient method in order to evaluate its control curvature. We will show that up to change the Riemannian metric on the manifold the control curvature of Zermelo's problem has a simple to handle expression which na

Akhlesh Lakhtakia

The solution of a boundary-value problem formulated for a modified Kretschmann configuration shows that a surface-plasmon wave can be excited at the planar interface of a sufficiently thin metal film and a nondissipative structurally chiral medium, provided the exciting plane wave is p-polarized. An estimate of the wavenumber of the surface-plasmon wave also

S. Moukouri

I apply a two-step renormalization group method to the study of the competition between antiferromagnetism (AFM) and superconductivity in an anisotropic 2D Hubbard model. I show that this simple model captures the essentials of the ground-state phases of the quasi 1D organic conductors. As found experimentally, the ground-state phase diagram is mostly AFM. T

Pascal Lambrechts, Don Stanley

Suppose that f:V->W is an embedding of closed oriented manifolds whose normal bundle has the structure of a complex vector bundle. It is well known in both complex and symplectic geometry that one can then construct a manifold W' which is the blow-up of W along V. Assume that dim(W)>2.dim(V)+2 and that H^1(f) is injective. We construct an algebraic model

Silvia Vaula

We investigate the ten dimensional origin of six dimensional F_4 variant supergravity with supersymmetric de Sitter background. We address first the issue of spontaneous compactification, showing that it consists of a warped compactification on a four sphere of a variant massive type IIA supergravity. Moreover we illustrate how the known D4-D8 brane solution

Jeremy Bailin, Josh D. Simon, Alberto D. Bolatto, Brad K. Gibson

Galactic disks in triaxial dark matter halos become deformed by the elliptical potential in the plane of the disk in such a way as to counteract the halo ellipticity. We develop a technique to calculate the equilibrium configuration of such a disk in the combined disk-halo potential, which is based on the method of Jog (2000) but accounts for the radial vari

Martin Chaplin

Water is necessary both for the evolution of life and its continuance. It possesses particular properties that cannot be found in other materials and that are required for life-giving processes. These properties are brought about by the hydrogen bonded environment particularly evident in liquid water. Each liquid water molecule is involved in about four hydr

Yimin Jiang, Mario Liu

"Granular elasticity," useful for calculating static stress distributions in granular media, is generalized by including the effects of slowly moving, deformed grains. The result is a hydrodynamic theory for granular solids that agrees well with models from soil mechanics.

Taku Nakajima, Masahiro Kaiden, Jun Korogi, Kimihiro Kimura

We have upgraded the 60-cm radio survey telescope located in Nobeyama, Japan. We developed a new waveguide-type sideband-separating SIS mixer for the telescope, which enables the simultaneous detection of distinct molecular emission lines both in the upper and lower sidebands. Over the RF frequency range of 205-240 GHz, the single-sideband receiver noise tem

Yimin Jiang, Mario Liu

Although fully elastic when static, granular media become transiently elastic when being slowly sheared -- during which both the elastic energy and stress relax. Starting from this observation, we cogently derive the framework for granular hydrodynamics, a set of differential equations consistent with general principles of physics, especially reversible and

Chen Wu, Wei-Liang Qian, Ru-Keng Su

An improved quark mass density- dependent model with the non-linear scalar sigma field and the $ω$-meson field is presented. We show that the present model can describe saturation properties, the equation of state, the compressibility and the effective nuclear mass of nuclear matter under mean field approximation successfully. The comparison of the present m

Lev Vaidman

The weak value of a variable O is a description of an effective interaction with that variable in the limit of weak coupling. It is particularly important for a pre- and post-selected quantum system.

Lev Vaidman

The two-state vector formalism (TSVF), the time-symmetric description of the standard quantum mechanics originated by Aharonov, Bergmann and Lebowitz is reviewed. The TSVF describes a quantum system at a particular time by two quantum states: the usual one, evolving forward in time, defined by the results of a complete measurement at the earlier time, and by

José Antonio Caballero

The results of the Koenigstuhl survey in the Southern Hemisphere are presented. I have searched for common-proper motion companions to 173 field very low-mass stars and brown dwarfs with spectral types > M5.0V and magnitudes J <= 14.5 mag. I have measured for the first time the common-proper motion of two new wide systems containing very low-mass components,

K. Wiersema, A. J. van der Horst, D. A. Kann, E. Rol

We present optical photometry and spectroscopy of the afterglow and host galaxy of gamma-ray burst 040924. This GRB had a rather short duration of T90 ~2.4s, and a well sampled optical afterglow light curve. We aim to use this dataset to find further evidence that this burst is consistent with a massive star core-collapse progenitor. We combine the afterglow

A. B. Dzyubenko, A. R. Todd

We consider a system of two interacting particles with like but unequal charges in a magnetic field in the planar geometry. We construct a complete basis of states compatible with both the axial symmetry and magnetic translations. The basis is obtained using a canonical transformation that generates effective quasiparticles with modified interactions. We est

J. J. Lin, T. C. Lee, S. W. Wang

Ever since the first discoveries of the quantum-interference transport in mesoscopic systems, the electron dephasing times, $τ_ϕ$, in the concentrated AuPd alloys have been extensively measured. The samples were made from different sources with different compositions, prepared by different deposition methods, and various geometries (1D narrow wires, 2D thin

S. Sadeh, Y. Rephaeli, J. Silk

In the standard Lambda CDM cosmological model with a Gaussian primordial density fluctuation field, the relatively low value of the mass variance parameter (sigma_8=0.74{+0.05}{-0.06}, obtained from the WMAP 3-year data) results in a reduced likelihood that the measured level of CMB anisotropy on the scales of clusters is due to the Sunyaev-Zeldovich (S-Z) e

G. Fabbri, F. Gozzi, A. Swiech

We study several aspects of the dynamic programming approach to optimal control of abstract evolution equations, including a class of semilinear partial differential equations. We introduce and prove a verification theorem which provides a sufficient condition for optimality. Moreover we prove sub- and superoptimality principles of dynamic programming and gi

Jiang-Hua Lu

We identify the cotangent bundle Lie algebroid of a Poisson homogeneous space G/H of a Poisson Lie group G as a quotient of a transformation Lie algebroid over G. As applications, we describe the modular vector fields of G/H, and we identify the Poisson cohomology of G/H with coefficients in powers of its canonical line bundle with relative Lie algebra cohom

Alexey Yamilov

We study analytically and numerically field/intensity correlations in wave transport through volume-disordered waveguide. The obtained channel and spacial correlations deviate from those found in framework of Dorokhov-Mello-Pereyra-Kumar (DMPK) formalism, that we relate to inapplicability of equivalent channel approximation in DMPK. We show that this can be

Alessandro Melchiorri, Luca Pagano, Stefania Pandolfi

A precise determination, and comparison, of the epoch of the onset of cosmic acceleration, at redshift z_acc, and of dark energy domination, at z_eq, provides an interesting measure with which to parameterize dark energy models. By combining several cosmological datasets we place constraints on the redshift and age of cosmological acceleration. For a Lambda-

Eugene I. Chiang, Ruth A. Murray-Clay

How do T Tauri disks accrete? The magneto-rotational instability (MRI) supplies one means, but protoplanetary disk gas is typically too poorly ionized to be magnetically active. Here we show that the MRI can, in fact, explain observed accretion rates for the sub-class of T Tauri disks known as transitional systems. Transitional disks are swept clean of dust

R. L. Grossman, R. G. Larson

It is known that there is a Hopf algebra structure on the vector space with basis all heap-ordered trees. We give a new bialgebra structure on the space with basis all permutations and show that there is a direct bialgebra isomorphism between the Hopf algebra of heap-ordered trees and the bialgebra of permutations.

Jordi Lopez Abad, Lionel Nguyen Van Thé

We study the oscillation stability problem for the Urysohn sphere, an analog of the distortion problem for $\ell_2$ in the context of the Urysohn space $\Ur$. In particular, we show that this problem reduces to a purely combinatorial problem involving a family of countable ultrahomogeneous metric spaces with finitely many distances.

Giulio Magli

The possible existence of astronomical references in the planning of the so-called Great Hopewell Road, a 90 Kilometres straight road composed of two parallel earthen embankments which, according to recent surveys, likely connected the Hopewell ceremonial centres of Newark and Chillicothe, Ohio, are investigated. It turns out that a very peculiar, although s

Nadia Sandoval-Figueroa, Víctor Romero-Rochín

We present the full thermodynamics of a fluid confined by an arbitrary external potential based on the virial expansion of the grand potential. The fluid may be classical or quantum and it is assumed that interatomic interactions are pairwise additive. We indicate how the appropriate &#34;generalized&#34; volume and pressure variables, that replace the usual

A. J. van der Horst, A. Kamble, L. Resmi, R. A. M. J. Wijers

We explore the physics behind one of the brightest radio afterglows ever, GRB 030329, at late times when the jet is non-relativistic. We determine the physical parameters of the blast wave and its surroundings, in particular the index of the electron energy distribution, the energy of the blast wave, and the density (structure) of the circumburst medium. We

G. E. Romero, A. T. Okazaki, M. Orellana, S. P. Owocki

LS I +61 303 is a puzzling Be/X-ray binary with variable gamma-ray emission at up TeV energies. The nature of the compact object and the origin of the high-energy emission are unclear. One family of models invokes particle acceleration in shocks from the collision between the B-star wind and a relativistic pulsar wind, while another centers on a relativistic

Jun Namikawa, Jun Tani

This paper proposes a novel learning method for a mixture of recurrent neural network (RNN) experts model, which can acquire the ability to generate desired sequences by dynamically switching between experts. Our method is based on maximum likelihood estimation, using a gradient descent algorithm. This approach is similar to that used in conventional methods

Alain Bachelot

We investigate the global solutions of the Dirac equation on the Anti-de-Sitter Universe. Since this space is not globally hyperbolic, the Cauchy problem is not, {\it a priori}, well-posed. Nevertheless we can prove that there exists unitary dynamics, but its uniqueness crucially depends on the ratio beween the mass $M$ of the field and the cosmological cons

Kartik K Iyer, E. V. Sampathkumaran

The compound Y2PdGe3 was earlier reported by us to be one of the very few ternary superconducting compounds (T_c= 3 K) belonging to the same structure as that of MgB2. Here we report the results of electrical resistivity, magnetization and heat capacity measurements at low temperatures on the solid solution with a nominal starting composition, Y2Pd(1-x)Pt(x)

Niharika Mohapatra, Kartik K Iyer, Sudhindra Rayaprol, E. V. Sampathkumaran

The results of ac and dc magnetic susceptibility isothermal magnetization and heat-capacity measurements as a function of temperature (T) are reported for Sr3NiRhO6 and Sr3NiPtO6 containing magnetic chains arranged in a triangular fashion in the basal plane and crystallizing in K4CdCl6-derived rhombohedral structure. The results establish that both the compo

Zuzanna Piwkowska, Martin Pospischil, Romain Brette, Julia Sliwa

Cortical neurons are subject to sustained and irregular synaptic activity which causes important fluctuations of the membrane potential (Vm). We review here different methods to characterize this activity and its impact on spike generation. The simplified, fluctuating point-conductance model of synaptic activity provides the starting point of a variety of me

Paolo Aluffi, Carel Faber

Every complex plane curve C determines a subscheme S of the $P^8$ of 3x3 matrices, whose projective normal cone (PNC) captures subtle invariants of C. In &#34;Limits of PGL(3)-translates of plane curves, I&#34; we obtain a set-theoretic description of the PNC and thereby we determine all possible limits of families of plane curves whose general element is is

M. D. Caballero-Garcia, J. M. Miller, E. Kuulkers, M. Diaz Trigo

We present broadband (3-500 keV) INTEGRAL X-ray spectra and X-ray/optical light curves of the luminous black hole X-ray transient and relativistic jet source GRO J1655-40. Our analysis covers four Target of Opportunity observations of the outburst that started in February 2005. We find that the high energy emission of GRO J1655-40 can be modelled well with a

Paolo Aluffi, Carel Faber

We classify all possible limits of families of translates of a fixed, arbitrary complex plane curve. We do this by giving a set-theoretic description of the projective normal cone (PNC) of the base scheme of a natural rational map, determined by the curve, from the $P^8$ of 3x3 matrices to the $P^N$ of plane curves of degree $d$. In a sequel to this paper we

B. Famaey, G. W. Angus, G. Gentile, H. Y. Shan

We summarize the status of Modified Newtonian Dynamics (MOND) in galaxy clusters. The observed acceleration is typically larger than the acceleration threshold of MOND in the central regions, implying that some dark matter is necessary to explain the mass discrepancy there. A plausible resolution of this issue is that the unseen mass in MOND is in the form o

R. Ramakumar, A. N. Das

We present a theoretical study of bose condensation of non-interacting bosons in finite lattices in quartic potentials in one, two, and three dimensions. We investigate dimensionality effects and quartic potential effects on single boson density of energy states, condensation temperature, condensate fraction, and specific heat. The results obtained are compa

E. Poem, J. Shemesh, I. Marderfeld, D. Galushko

We present an experimental and theoretical study of the polarized photoluminescence spectrum of single semiconductor quantum dots in various charge states. We compare our high resolution polarization sensitive spectral measurements with a new many-carrier theoretical model, which was developed for this purpose. The model considers both the isotropic and anis

N. P. Bondar, I. L. Kovalenko, D. F. Avgustinovich, N. N. Kudryavtseva

Anhedonia is one of the key symptoms of depression in humans. Consumption of 1% sucrose solution supplemented with 0.2% vanillin was studied in two experimental contexts in male mice living under chronic social stress induced by daily experience of defeats in agonistic interactions and leading to development of depression. In the first experiment, vanillin s

Roberto Zucchini

We revisit our earlier work on the AKSZ formulation of topological sigma model on generalized complex manifolds, or Hitchin model. We show that the target space geometry geometry implied by the BV master equations is Poisson--quasi--Nijenhuis geometry recently introduced and studied by Stiénon and Xu (in the untwisted case). Poisson--quasi--Nijenhuis geometr

Kathy L. Cooksey, Jason X. Prochaska, Hsiao-Wen Chen, John S. Mulchaey

We present a detailed analysis of the intergalactic metal-line absorption systems in the archival HST/STIS and FUSE ultraviolet spectra of the low-redshift quasar PKS1302-102 (z_QSO = 0.2784). We supplement the archive data with CLOUDY ionization models and a survey of galaxies in the quasar field. There are 15 strong Lya absorbers with column densities logN

Hiranya V. Peiris, Daniel Baumann, Brett Friedman, Asantha Cooray

A characteristic of D-brane inflation is that fluctuations in the inflaton field can propagate at a speed significantly less than the speed of light. This yields observable effects that are distinct from those of single-field slow roll inflation, such as a modification of the inflationary consistency relation and a potentially large level of non-Gaussianitie

Michael A. Shulman

In some bicategories, the 1-cells are `morphisms&#39; between the 0-cells, such as functors between categories, but in others they are `objects&#39; over the 0-cells, such as bimodules, spans, distributors, or parametrized spectra. Many bicategorical notions do not work well in these cases, because the `morphisms between 0-cells&#39;, such as ring homomorphi

Yi Liao, Ji-Yuan Liu

Unparticles as suggested by Georgi are identities that are not constrained by dispersion relations but are governed by their scaling dimension, d. Their coupling to particles can result in macroscopic interactions between matter, that are generally an inverse nonintegral power of distance. This is totally different from known macroscopic forces. We use the p

Ravi Kumar Kopparapu, Chad R. Hanna, Vicky Kalogera, Richard O&#39;Shaughnessy

An up-to-date catalog of nearby galaxies considered as hosts of binary compact objects is provided with complete information about sky position, distance, extinction-corrected blue luminosity and error estimates. With our current understanding of binary evolution, rates of formation and coalescence for binary compact objects scale with massive-star formation

Anibal D. Medina, Nausheen R. Shah, Carlos E. M. Wagner

We compute the Coleman Weinberg effective potential for the Higgs field in RS Gauge-Higgs unification scenarios based on a bulk SO(5) x U(1)_X gauge symmetry, with gauge and fermion fields propagating in the bulk and a custodial symmetry protecting the generation of large corrections to the T parameter and the coupling of the Z to the bottom quark. We demons

Fulai Guo, S. Peng OH

Recent observations show that the cooling flows in the central regions of galaxy clusters are highly suppressed. Observed AGN-induced cavities/bubbles are a leading candidate for suppressing cooling, usually via some form of mechanical heating. At the same time, observed X-ray cavities and synchrotron emission point toward a significant non-thermal particle

S. Misra, N. C. Bishop, E. Tutuc, M. Shayegan

We report interlayer tunneling measurements between very dilute two-dimensional GaAs hole layers. Surprisingly, the shape and temperature-dependence of the tunneling spectrum can be explained with a Fermi liquid-based tunneling model, but the peak amplitude is much larger than expected from the available hole band parameters. Data as a function of parallel m

Boris Shoikhet

Let $\g_1$ and $\g_2$ be two dg Lie algebras, then it is well-known that the $L_\infty$ morphisms from $\g_1$ to $\g_2$ are in 1-1 correspondence to the solutions of the Maurer-Cartan equation in some dg Lie algebra $\Bbbk(\g_1,\g_2)$. Then the gauge action by exponents of the zero degree component $\Bbbk(\g_1,\g_2)^0$ on $MC\subset\Bbbk(\g_1,\g_2)^1$ gives

German A. Enciso

A standard result by Smale states that n dimensional strongly cooperative dynamical systems can have arbitrary dynamics when restricted to unordered invariant hyperspaces. In this paper this result is extended to the case when all solutions of the strongly cooperative system are bounded and converge towards one of only two equilibria outside of the hyperplan

M. Omerbashich

Lieberman and Melott built their recent arXiv preprint 0704.2896 on my published paper and (a preprint of) a subsequent comment by Liebermans associate Cornette. But had this group waited for the Cornette comment to actually appear in print together with the expected Reply, they would have learned that his comment exposes Cornettes confusion that likely was

F. Assaoui, T. Lhallabi

The N = 4 superfield phase space coordinates are given in the harmonic superspace. The expressions of the N = 4 classical equations of motion are determined in terms of the spinorial and harmonic supercharges. Furthermore, the N = 4 supersymmetric actions are obtained by means of the fermionic and harmonic functionals. On the other hand, the Hamiltonian quan

A. J. van der Horst, A. Kamble, R. A. M. J. Wijers, L. Resmi

Radio observations of gamma-ray burst (GRB) afterglows are essential for our understanding of the physics of relativistic blast waves, as they enable us to follow the evolution of GRB explosions much longer than the afterglows in any other wave band. We have performed a three-year monitoring campaign of GRB 030329 with the Westerbork Synthesis Radio Telescop

A. J. van der Horst, A. Kamble, R. A. M. J. Wijers, L. Resmi

Radio observations of gamma-ray burst (GRB) afterglows are essential for our understanding of the physics of relativistic blast waves, as they enable us to follow the evolution of GRB explosions much longer than the afterglows in any other wave band. We have performed a three-year monitoring campaign of GRB 030329 with the Westerbork Synthesis Radio Telescop

Luis Lehner, Osvaldo M. Moreschi

We revisit the calculation of gravitational radiation through the use of Weyl scalars. We point out several possible problems arising from gauge and tetrad ambiguities and ways to address them. Our analysis indicates how, relatively simple corrections can be introduced to remove these ambiguities.

S. Sathiya Keerthi, John A. Tomlin

We present an algorithm for constructing an optimal slate of sponsored search advertisements which respects the ordering that is the outcome of a generalized second price auction, but which must also accommodate complicating factors such as overall budget constraints. The algorithm is easily fast enough to use on the fly for typical problem sizes, or as a su

Andrea Alu, Alessandro Salandrino, Nader Engheta

We present here a model for the coupling among small nanoparticles excited by an optical electric field in the framework of our optical lumped nanocircuit theory [N. Engheta, A. Salandrino, and A. Alu Phys. Rev. Lett. 95, 095504 (2005)]. We derive how this coupling affects the corresponding nanocircuit model by adding controlled sources that depend on the op

Thierry Coulbois, Arnaud Hilion, Martin Lustig

We continue in this article the study of laminations dual to very small actions of a free group F on R-trees. We prove that this lamination determines completely the combinatorial structure of the R-tree (the so-called observers' topology). On the contrary the metric is not determined by the lamination, and an R-tree may be equipped with different metrics wh

Barben-Jean Coffi-Nketsia, Labib Haddad

Full details are given for the definition and construction of the wreath product of two arbitrary Lie algebras, in the hope that it can lead to the definition of a suitable Lie group to be the wreath product of two given Lie groups. In the process, quite a few new notions are needed, and introduced. Such are, for example : Formal series with variables in a v

S. Reffert

These lecture notes are meant to serve as an introduction to some geometric constructions and techniques (in particular the ones of toric geometry) often employed by the physicist working on string theory compactifications. The emphasis is wholly on the geometry side, not on the physics. The treated topics include toroidal orbifolds, methods of toric geometr

Luigi Accardi, Andreas Boukas

Motivated by the work of Segal and Segal on the Black-Scholes pricing formula in the quantum context, we study a quantum extension of the Black-Scholes equation within the context of Hudson-Parthasarathy quantum stochastic calculus. Our model includes stock markets described by quantum Brownian motion and Poisson process.

Enrico Cappellaro, Maria Teresa Botticella, Laura Greggio

We briefly review the contribution of SN rate measurements to the debate on SN progenitor scenarios. We find that core collapse rates confirms the rapid evolution of the star formation rate with redshift. After accounting for the dispersion of SN Ia measurements and uncertainty of the star formation history, the standard scenarios for SN Ia progenitors appea

S. C. Tiwari

A generalized harmonic map equation is presented based on the proposed action functional in the Weyl space (PLA, 135, 315, 1989).

Charu Saxena, Rini Kaur, P. Arun

The reaction time of a group of students majoring in Physics is reported here. Strong co-relation between fatigue, reaction time and performance have been seen and may be useful for academicians and administrators responsible of working out time-tables, course structures, students counsellings etc.

Gamal Gergess Lamee Nashed

We show that the energy distribution of the brane-world black holes given by Salti et al. in the context of teleparallel theory is not right. We give the correct formula of energy of those black hole.

Maria J. Esteban, Michael Loss

Distinguished selfadjoint extensions of Dirac operators are constructed for a class of potentials including Coulombic ones up to the critical case, $-|x|^{-1}$. The method uses Hardy-Dirac inequalities and quadratic form techniques.

Sylviane R. Schwer

Representing and reasoning about qualitative temporal information is an essential part of many artificial intelligence tasks. Lots of models have been proposed in the litterature for representing such temporal information. All derive from a point-based or an interval-based framework. One fundamental reasoning task that arises in applications of these framewo

Helen Armstrong, Christopher K. Carter, Kevin F. Wong, Robert Kohn

A Bayesian approach is used to estimate the covariance matrix of Gaussian data. Ideas from Gaussian graphical models and model selection are used to construct a prior for the covariance matrix that is a mixture over all decomposable graphs. For this prior the probability of each graph size is specified by the user and graphs of equal size are assigned equal

Dao T. Khoa, Hoang Sy Than, Do Cong Cuong

A consistent folding model analysis of the ($ΔS=0, ΔT=1$) charge exchange \pn reaction measured with $^{48}$Ca, $^{90}$Zr, $^{120}$Sn and $^{208}$Pb targets at the proton energies of 35 and 45 MeV is done within a two-channel coupling formalism. The nuclear ground state densities given by the Hartree-Fock-Bogoljubov formalism and the density dependent CDM3Y6

Yi-Fang Chang

It is proved that local Lorentz transformations for different systems cannot derive varying speed of light. Based on the special relativity principle, an invariant speed is necessarily obtained. Therefore, the exact basic principles of the special relativity should be redefined as: I. The special relativity principle, which derives necessarily an invariant s

Krisztian Peters

Recent preliminary results obtained by the CDF and D0 Collaborations on searches for the Higgs boson in proton anti-proton collisions at Sqrt(s)=1.96 TeV at the Fermilab Tevatron collider are discussed. The data, corresponding to integrated luminosities of about 1 fb-1, show no excess of a signal above the expected background in any of the decay channels exa

Jan Kurzyk, Jozef Spałek, Włodzimierz Wójcik

The optimized single-particle wave functions contained in the parameters of the Hubbard model (t and U) were determined for an infinite atomic chain. In effect, the electronic properties of the chain as a function of interatomic distance R were obtained and compared for the Lieb - Wu exact solution (LW), the Gutzwiller-Wave-Function approximation (GWF), and

Hirotaka Tamanoi

Cohen and Godin constructed positive boundary topological quantum field theory (TQFT) structure on the homology of free loop spaces of oriented closed smooth manifolds by associating a certain operations called string operations to orientable surfaces with parametrized boundaries. We show that all TQFT string operations associated to surfaces of genus at lea

D. Malesani, S. Covino, P. D&#39;Avanzo, V. D&#39;Elia

New information on short/hard gamma-ray bursts (GRBs) is being gathered thanks to the discovery of their optical and X-ray afterglows. However, some key aspects are still poorly understood, including the collimation level of the outflow, the duration of the central engine activity, and the properties of the progenitor systems. We want to constrain the physic

Alexis Larranaga

Traversable wormholes are objects that present a lot of interest in the last years because of their geometric features and their relation with exotic matter. In this paper we presnt a review of the principal characteristics of traversable Morris-Thorne wormholes, their construction proccess and some aspects about the exotic matter that is needed in order to

Joseph H. Rhee, Inseok Song, B. Zuckerman

Most Vega-like stars have far-infrared excess (60micron or longward in IRAS, ISO, or Spitzer MIPS bands) and contain cold dust (<~150K) analogous to the Sun&#39;s Kuiper-Belt region. However, dust in a region more akin to our asteroid belt and thus relevant to the terrestrial planet building process is warm and produces excess emission in mid-infrared wavele

Igor Nikolaev

A covariant functor on the elliptic curves with complex multiplication is constructed. The functor takes values in the noncommutative tori with real multiplication. A conjecture on the rank of an elliptic curve is formulated.

Rogerio de Sousa, Joel E. Moore

The magnon and optical phonon spectrum of an incommensurate multiferroic such as BiFeO3 is considered in the framework of a phenomenological Landau theory. The resulting spin wave spectrum is quite distinct from commensurate substances due to soft mode anisotropy and magnon zone folding. The former allows electrical control of spin wave propagation via reori

E. Akofor, A. P. Balachandran, S. G. Jo, A. Joseph

We show that despite the inherent non-locality of quantum field theories on the Groenewold-Moyal (GM) plane, one can find a class of ${\bf C}$, ${\bf P}$, ${\bf T}$ and ${\bf CPT}$ invariant theories. In particular, these are theories without gauge fields or with just gauge fields and no matter fields. We also show that in the presence of gauge fields, one c

Wei Zhang, L. -M. Duan

We consider a trapped Fermi gas with population imbalance at finite temperatures and map out the detailed phase diagram across a wide Feshbach resonance. We take the Larkin-Ovchinnikov-Fulde-Ferrel (LOFF) state into consideration and minimize the thermodynamical potential to ensure stability. Under the local density approximation, we conclude that a stable L

C. -J. Yang, Ch. Elster, D. R. Phillips

The leading-order nucleon-nucleon (NN) potential derived from chiral perturbation theory consists of one-pion exchange plus a short-distance contact interaction. We show that in the 1S0 and 3S1-3D1 channels renormalization of the Lippmann-Schwinger equation for this potential can be achieved by performing one subtraction. This subtraction requires as its onl

J. B. Sokoloff

It is shown using a method based on a modified version of the mean field theory of Miklavic Marcelja that it should be possible for osmotic pressure due to the counterions associated with the two polyelectrolyte polymer brush coated surfaces to support a reasonable load (i.e., about $10^6 Pa$) with the brushes held sufficiently far apart to prevent entanglem

Javier L. Albacete

Predictions for the pseudorapidity density of charged particles produced in Pb-Pb central collisions at $\sqrt{s_{NN}}=5.5$ TeV are presented. Particle production in such collisions is computed in the framework of k_t-factorization, using running coupling non-linear evolution to determine the transverse momentum and rapidity dependence of the nuclear uninteg

Paulsamy Muruganandam, Fernando F. Ferreira, Hassan F. El-Nashar, Hilda A. Cerdeira

Here we present a system of coupled phase oscillators with nearest neighbors coupling, which we study for different boundary conditions. We concentrate at the transition to total synchronization. We are able to develop exact solutions for the value of the coupling parameter when the system becomes completely synchronized, for the case of periodic boundary co