March 2008 arXiv papers — page 23

J. Knoll

The question of decoupling and freeze-out is reinvestigated and analysed in terms of transparent semi-classical decoupling formulae, which provide a smooth decoupling in time both, for single and two particle inclusive spectra. They generalise frequently employed instantaneous freeze-out procedures and provide simple relations between the damping width and t

Yusuke Sasano

We study the phase space of the equations of Ince's table from the viewpoint of its accessible singularities and local index.

Mojtaba Mohammadi Najafabadi

In this article we aim to estimate the bounds on the noncommutative scale $Λ_{NC}$ and to extract the 95% exclusion contours for some $θ_{μν}$ components using the recent measurements of the top quark width and the $W$ boson polarization in top pair events from CDF experiment at Tevatron.

Mauro Sellitto

Asymmetric exclusion processes with locally reversible kinetic constraints are introduced to investigate the effect of non-conservative driving forces in athermal systems. At high density they generally exhibit rheological-like behavior, negative differential resistance, two-step structural relaxation, dynamical heterogeneity and, possibly, a jamming transit

Alireza Rafiee, Patrick B. Hall

Wang et al. (2006) estimated an average radiative efficiency of 30% -- 35% for quasars at moderate redshift. We find that their method is not independent of quasar lifetimes and thus that quasars do not necessarily have such high efficiencies. Nonetheless, it is possible to derive interrelated constraints on quasar lifetimes, Eddington ratios, and radiative

Tianshu Luo, Yimu Guo

In this paper we proposed a proposition: for any nonconservative classical mechanical system and any initial condition, there exists a conservative one; the two systems share one and only one common phase curve; the Hamiltonian of the conservative system is the sum of the total energy of the nonconservative system on the aforementioned phase curve and a cons

Michael J. Schlosser

We establish Taylor series expansions in rational (and elliptic) function bases using E. Rains' elliptic extension of the Askey-Wilson divided difference operator. The expansion theorem we consider extends M.E.H. Ismail's expansion for the Askey-Wilson monomial basis. Three immediate applications (essentially already due to Rains) include simple proofs of Fr

Kiyonori Gomi

We provide a finite-dimensional model of the twisted K-group twisted by any degree three integral cohomology class of a CW complex. One key to the model is Furuta's generalized vector bundle, and the other is a finite-dimensional approximation of Fredholm operators.

Ivan Calvo, Luis Garcia, Benjamin A. Carreras, Raul Sanchez

In toroidal geometry, and prior to the establishment of a fully developed turbulent state, the so-called topological instability of the pressure-gradient-driven turbulence is observed. In this intermediate state, a narrow spectral band of modes dominates the dynamics, giving rise to the formation of iso-surfaces of electric potential with a complicated topol

Aviv Censor, Daniel Markiewicz

I. Raeburn and J. Taylor have constructed continuous-trace C*-algebras with a prescribed Dixmier-Douady class, which also depend on the choice of an open cover of the spectrum. We study the asymptotic behavior of these algebras with respect to certain refinements of the cover and appropriate extension of cocycles. This leads to the analysis of a limit groupo

Qinian Jin

In this paper we consider the iteratively regularized Gauss-Newton method for solving nonlinear ill-posed inverse problems. Under merely Lipschitz condition, we prove that this method together with an a posteriori stopping rule defines an order optimal regularization method if the solution is regular in some suitable sense.

R. Ciftci

Excited quark production at future $γp$ colliders is studied. Namely, $γp \to q^{*}X$ with subsequent $q^{*}\to gq$ and $γq $ decay channels are considered. Signatures for discovery of the excited quark and corresponding standard model backgrounds are discussed in detail. Discovery limits for excited quark masses and achievable values of compositeness parame

Pierre Comon

A matrix (and any associated linear system) will be referred to as structured if it has a small displacement rank. It is known that the inverse of a structured matrix is structured, which allows fast inversion (or solution), and reduced storage requirements. According to two definitions of displacement structure of practical interest, it is shown here that s

Monique Lejeune Jalabert, Bernard Teissier, Jean-Jacques Risler

This text has two parts; the first is the essentially unmodified text of the 1973-74 seminar of M. Lejeune-Jalabert and B. Teissier on integral dependence in complex analytic geometry with J-J. Risler's appendix on the Lojasiewicz exponents in the real analytic framework. The second part consists of seven complements written in 2007 surveying recent resu

C. Davies, S. Faccini, H. Lipkin, L. Maiani

A round table held during the Hadron07 Conference focusing on experimental observations of new hadronic states, on theoretical perspectives for their description, and on the role of hadronic spectroscopy in furthering our knowledge of the fundamental theory of strong interactions.

Gerard Freixas i Montplet

We prove arithmetic Riemann-Roch and Hilbert-Samuel type formulae for pointed stable curves. We give applications to volumes of lattices of integral cusps forms for pointed stable curves of genus 0.

V Sriram, Ganesh Narayan, K Gopinath

We describe SAFIUS, a secure accountable file system that resides over an untrusted storage. SAFIUS provides strong security guarantees like confidentiality, integrity, prevention from rollback attacks, and accountability. SAFIUS also enables read/write sharing of data and provides the standard UNIX-like interface for applications. To achieve accountability

Li Chen

Image segmentation is to separate an image into distinct homogeneous regions belonging to different objects. It is an essential step in image analysis and computer vision. This paper compares some segmentation technologies and attempts to find an automated way to better determine the parameters for image segmentation, especially the connectivity value of $λ$

Markus A. Dahlem, Felix M. Schneider, Eckehard Schoell

The stability of cortical function depends critically on proper regulation. Under conditions of migraine and stroke a breakdown of transmembrane chemical gradients can spread through cortical tissue. A concomitant component of this emergent spatio-temporal pattern is a depolarization of cells detected as slow voltage variations. The velocity of ~3 mm/min ind

Marios Tsatsos

The basic notion of how topoi can be utilized in physics is presented here. Topos and category theory serve as valuable tools which extend our ordinary set-theoretical conceptions, can further the study of quantum logic and give rise to new and 'neo-realistic' descriptions of quantum physics, i.e. make possible the construction of a general scheme fo

Zhien Lu, Ka-di Zhu

The optical properties of hybrid molecules composed of semiconductor and metal nanoparticles with a weak probe in a strong pump field are investigated theoretically. Excitons in such a hybrid molecule demonstrate novel optical properties due to the coupling between exciton and plasmon. It is shown that a non-absorption hole induced by coherent population osc

Victor Beresnevich, Sanju Velani

In this paper we discuss a general problem on metrical Diophantine approximation associated with a system of linear forms. The main result is a zero-one law that extends one-dimensional results of Cassels and Gallagher. The paper contains a discussion on possible generalisations including a selection of various open problems.

Adi Rebenshtok, Eli Barkai

We find a general formula for the distribution of time averaged observables for weakly non-ergodic systems. Such type of ergodicity breaking is known to describe certain systems which exhibit anomalous fluctuations, e.g. blinking quantum dots and the sub-diffusive continuous time random walk model. When the fluctuations become normal we recover usual ergodic

M. A. Dahlem, G. Hiller, A. Panchuk, E. Schoell

We study the nonlinear dynamics of two delay-coupled neural systems each modelled by excitable dynamics of FitzHugh-Nagumo type and demonstrate that bistability between the stable fixed point and limit cycle oscillations occurs for sufficiently large delay times and coupling strength. As the mechanism for these delay-induced oscillations we identify a saddle

Victor Beresnevich, Vasily Bernik, Maurice Dodson, Sanju Velani

The idea of using measure theoretic concepts to investigate the size of number theoretic sets, originating with E. Borel, has been used for nearly a century. It has led to the development of the theory of metrical Diophantine approximation, a branch of Number Theory which draws on a rich and broad variety of mathematics. We discuss some recent progress and o

Achamveedu Gopakumar, Gerhard Schaefer

Binary black-hole coalescence is treated semi-analytically by a novel approach. Our prescription employs the conservative Skeleton Hamiltonian that describes orbiting Brill-Lindquist wormholes (termed punctures in Numerical Relativity) within a waveless truncation to the Einstein field equations [G. Faye, P. Jaranowski and G. Schäfer, Phys. Rev. D {\bf 69},

Elisabetta Pallante

I review basic concepts of chiral effective field theories guided by an historical perspective: from the first ideas to the merging with other effective frameworks, and to the interplay with lattice field theory. The impact of recent theoretical developments on phenomenological predictions is reviewed with attention for rare decays, and charm physics. I conc

Victor Katsnelson

The paper deals with root problems for two classes of univariate polynomials both of geometric origin. The first class discussed, the class of Steiner polynomial, consists of polynomials, each associated with a compact convex set V in R^n. A polynomial of this class describes the volume of the set V+tB^n as a function of t, where t is a positive number and B

Anselm Vossen

This lecture will introduce the Support Vector algorithms for classification and regression. They are an application of the so called kernel trick, which allows the extension of a certain class of linear algorithms to the non linear case. The kernel trick will be introduced and in the context of structural risk minimization, large margin algorithms for class

Anselm Vossen

This document introduces basics in data preparation, feature selection and learning basics for high energy physics tasks. The emphasis is on feature selection by principal component analysis, information gain and significance measures for features. As examples for basic statistical learning algorithms, the maximum a posteriori and maximum likelihood classifi

Yu. N. Uzikov

COSY data on the cross section of the reaction pp -> {pp}_s pi^0, where {pp}_s is the proton pair in the 1S0 state at small excitation energy E_{pp}=0-3 MeV, recently obtained for beam energies 0.5 - 2.0 GeV are analyzed within the one-pion exchange model. The model is based on the subprocess pi^0 p -> pi^0 p and final state pp-interaction. A broad maximum o

Turan Birol, Özgür E. Müstecaplıoğlu

Reviewing the ideas developed in, the ground state life time of a finite size atomic Bose Einstein condensate is studied for coherent, squeezed coherent and thermal coherent ground states. Ground state evolution of coherent and squeezed coherent states in a double well potential is studied. Effects of thin spectrum on Bose-Einstein condensates is discussed a

J. Zhan, W. A. Dudek, Y. B. Jun

We introduce the concept of quasi-coincidence of a fuzzy interval value with an interval valued fuzzy set. By using this new idea, we introduce the notions of interval valued $(\in,\ivq)$-fuzzy filters of pseudo $BL$-algebras and investigate some of their related properties. Some characterization theorems of these generalized interval valued fuzzy filters ar

Wee Peng Tay, John Tsitsiklis, Moe Win

We consider the problem of decentralized detection in a network consisting of a large number of nodes arranged as a tree of bounded height, under the assumption of conditionally independent, identically distributed observations. We characterize the optimal error exponent under a Neyman-Pearson formulation. We show that the Type II error probability decays ex

M. A. Jafarizadeh, R. Sufiani, S. F. Taghavi, E. Barati

Following the prescription of Ref. \cite{PST} in which perfect state transference (PST) of a qubit over distance regular spin networks was discussed, in this paper PST of an arbitrary $d$-level quantum state (qudit) over antipodes of more general networks called pseudo distance-regular networks, is investigated. In fact, the spectral analysis techniques used

Hyeong-Chan Kim, Chaiho Rim, Jae Hyung Yee

We present the Casimir energy of spherical shell, for the symmetrically deformed scalar field in $κ$-Minkowski space-time, satisfying Dirichlet boundary condition. The Casimir energy shows the particle anti-particle symmetry contrary to the asymmetrically deformed case. In addition, the deformation effect starts from $O(1/κ)$ term unlike in the parallel plat

Christopher R. Moon, Laila S. Mattos, Brian K. Foster, Gabriel Zeltzer

Quantum phase is not a direct observable and is usually determined by interferometric methods. We present a method to map complete electron wave functions, including internal quantum phase information, from measured single-state probability densities. We harness the mathematical discovery of drum-like manifolds bearing different shapes but identical resonanc

V. A. Stephanovich, M. D. Glinchuk, R. Blinc

We show that the presence of free carriers in a substance can generate the multiferroic behavior. Namely, if the substance has mixed-valence ions, which can supply free carriers and have electric dipole and spin moments, all three types of long-range order (ferromagnetic, ferroelectric and magnetoelectric (ME)) can occur at low temperature. The physical orig

Y. Xu, J. J. Li, K. Hachisuka, J. D. Pandian

We present the results of a high sensitivity survey for 6.7 GHz methanol masers towards 22 GHz water maser using the 100 m Efflesberg telescope. A total of 89 sources were observed and 10 new methanol masers were detected. The new detections are relatively faint with peak flux densities between 0.5 and 4.0 Jy. A nil detection rate from low-mass star forming

Masahiro Hotta

In this paper, a protocol is proposed in which energy extraction from local vacuum states is possible by using quantum measurement information for the vacuum state of quantum fields. In the protocol, Alice, who stays at a spatial point, excites the ground state of the fields by a local measurement. Consequently, wavepackects generated by A' measurement p

Robert Connelly, Patrick Fowler, Simon Guest, Bernd Schulze

Maxwell's rule from 1864 gives a necessary condition for a framework to be isostatic in 2D or in 3D. Given a framework with point group symmetry, group representation theory is exploited to provide further necessary conditions. This paper shows how, for an isostatic framework, these conditions imply very simply stated restrictions on the numbers of those

Álvaro Villalobos, Amina Helmi

We present simulations of the formation of thick disks via the accretion of two-component satellites onto a pre-existing thin disk. Our goal is to establish the detailed characteristics of the thick disks obtained in this way, as well as their dependence on the initial orbital and internal properties of the accreted objects. We find that mergers with 10-20%

Maxim Pospelov, Adam Ritz

We consider the direct and indirect detection signatures of WIMPs χ^0 in kinematic regimes with a heavier, but nearly degenerate, charged state χ^{+-}. For small splittings of O(10) MeV, the scattering of WIMPs off nuclei may be dominated by inelastic recombination processes mediated by the formation of (χ^- N) bound states, leading to a distinct signature f

E. Glasner, M. Megrelishvili

For a topological group G, we show that a compact metric G-space is tame if and only if it can be linearly represented on a separable Banach space which does not contain an isomorphic copy of $l_1$ (we call such Banach spaces, Rosenthal spaces). With this goal in mind we study tame dynamical systems and their representations on Banach spaces.

Andrzej J. Maciejewski, Maria Przybylska, Tomasz Stachowiak, Marek Szydlowski

We investigate the Liouvillian integrability of Hamiltonian systems describing a universe filled with a scalar field (possibly complex). The tool used is the differential Galois group approach, as introduced by Morales-Ruiz and Ramis. The main result is that the generic systems with minimal coupling are non-integrable, although there still exist some values

Gao Xianlong

Using the Bethe-ansatz density-functional theory, we study a one-dimensional Hubbard model of confined attractively interacting fermions in the presence of a uniformly distributed disorder. The strongly-correlated Luther-Emery nature of the attractive one-dimensional Hubbard model is fully taken into account as the reference system in the density-functional

S. Harfst, A. Gualandris, D. Merritt, S. Mikkola

We describe a novel N-body code designed for simulations of the central regions of galaxies containing massive black holes. The code incorporates Mikkola's 'algorithmic' chain regularization scheme including post-Newtonian terms up to PN2.5 order. Stars moving beyond the chain are advanced using a fourth-order integrator with forces computed on a

Valentin Goranko, Dmitry Shkatov

We develop an incremental tableau-based decision procedures for the Alternating-time temporal logic ATL and some of its variants. While running within the theoretically established complexity upper bound, we claim that our tableau is practically more efficient in the average case than other decision procedures for ATL known so far. Besides, the ease of its a

Andrew Gacek

Abella is an interactive system for reasoning about aspects of object languages that have been formally presented through recursive rules based on syntactic structure. Abella utilizes a two-level logic approach to specification and reasoning. One level is defined by a specification logic which supports a transparent encoding of structural semantics rules and

Takahiro Hatano

Rheological properties of a dense granular material consisting of frictionless spheres are investigated. It is found that the shear stress, the pressure, and the kinetic temperature obey critical scaling near the jamming transition point, which is considered as a critical point. These scaling laws have some peculiar properties in view of conventional critica

Pedro Geraldo

In this paper is stablished a characterization of the solutions of the equation: zeta(z) = 0. Then such a characterization is used to give a proof for Riemann is Conjecture.

Selman Akbulut, Cagri Karakurt

Here we show that every compact smooth 4-manifold X has a structure of a Broken Lefschetz Fibration (BLF in short). Furthermore, if b_{2}^{+}(X)> 0 then it also has a Broken Lefschetz Pencil structure (BLP) with nonempty base locus. This imroves a Theorem of Auroux, Donaldson and Katzarkov, and our proof is topological (i.e. uses 4-dimensional handlebody the

Rui A. C. Ferreira, Delfim F. M. Torres

We prove some new retarded integral inequalities. The results generalize those in [J. Math. Anal. Appl. 301 (2005), no. 2, 265--275].

M. Mattes, M. Sorg

The lowest energy levels of positronium are studied in the non-relativistic approximation within the framework of Relativistic Schrödinger Theory (RST). Since it is very difficult to find the exact solutions of the RST field equations (even in the non-relativistic limit), an approximation scheme is set up on the basis of the hydrogen-like wave functions (i.e

Gerhard de Koning Gans, Jaap-Henk Hoepman, Flavio D. Garcia

The MIFARE Classic is the most widely used contactless smart card in the market. Its design and implementation details are kept secret by its manufacturer. This paper studies the architecture of the card and the communication protocol between card and reader. Then it gives a practical, low-cost, attack that recovers secret information from the memory of the

Imre Kondor, Istvan Varga-Haszonits

It is shown that the axioms for coherent risk measures imply that whenever there is an asset in a portfolio that dominates the others in a given sample (which happens with finite probability even for large samples), then this portfolio cannot be optimized under any coherent measure on that sample, and the risk measure diverges to minus infinity. This instabi

Gui-Jun Ding

We construct a supersymmetric model based on $T'\otimes Z_3\otimes Z_9$ flavor symmetry. At the leading order, the charged lepton mass matrix is not diagonal, $T'$ is broken completely, and the hierarchy in the charged lepton masses is generated naturally. Nearly tri-bimaximal mixing is predicted, subleading effects induce corrections of order $λ^2$,

Tim Ledwig, Hyun-Chul Kim, Klaus Goeke

We investigate the vector transition form factors of the nucleon and vector meson K^* to the pentaquark baryon Theta^+ within the framework of the SU(3) chiral quark-soliton model. We take into account the rotational 1/N_c and linear $m_{\rm s}$ corrections, assuming isospin symmetry and employing the symmetry-conserving quantization. It turns out that the l

Kiyotomo Ichiki, Yong-Yeon Keum

We investigate whether interaction between massive neutrinos and quintessence scalar field is the origin of the late time accelerated expansion of the universe. We present explicit formulas of the cosmological linear perturbation theory in the neutrinos probes of dark-energy model, and calculate cosmic microwave background anisotropies and matter power spect

Sagar Chakraborty, Mogens H. Jensen, Amartya Sarkar

Applying a modified version of the Gledzer-Ohkitani-Yamada (GOY) shell model, the signatures of so-called two-dimensionalization effect of three-dimensional incompressible, homogeneous, isotropic fully developed unforced turbulence have been studied and reproduced. Within the framework of shell models we have obtained the following results: (i) progressive s

E94010 Collaboration, K. Slifer, M. Amarian, L. Auerbach

We present a measurement of the spin-dependent cross sections for the \vec{^3He}(\vec{e},e&#39;)X} reaction in the quasielastic and resonance regions at four-momentum transfer 0.1 < Q^2< 0.9 GeV^2. The spin-structure functions have been extracted and used to evaluate the nuclear Burkhardt--Cottingham and extended GDH sum rules for the first time. Impulse app

Dmitry B. Uskov, Alexander L. Burin

Microscopic mechanisms of positive charge transfer in DNA remain unclear. A quantum state of electron hole in DNA is determined by the competition of the pi-stacking interaction $b$ sharing a charge between different base pairs and the interaction $λ$ with the local environment which attempts to trap charge. To determine which interaction dominates we invest

Maximilien Gadouleau, Zhiyuan Yan

Constant-dimension codes have recently received attention due to their significance to error control in noncoherent random linear network coding. What the maximal cardinality of any constant-dimension code with finite dimension and minimum distance is and how to construct the optimal constant-dimension code (or codes) that achieves the maximal cardinality bo

Manoussos G. Grillakis, Dionisios Margetis

We study the evolution of a many-particle system whose wave function obeys the N-body Schroedinger equation under Bose symmetry. The system Hamiltonian describes pairwise particle interactions in the absence of an external potential. We derive apriori dispersive estimates that express the overall repulsive nature of the particle interactions. These estimates

Shanti Deemyad, Isaac F. Silvera

The insulator to metal transition in solid hydrogen was predicted over 70 years ago but the demonstration of this transition remains a scientific challenge. In this regard, a peak in the temperature vs. pressure melting line of hydrogen may be a possible precursor for metallization. However, previous measurements of the fusion curve of hydrogen have been lim

A. A. Karawia

In this paper we present an efficient computational and symbolic algorithms for solving a backward pentadiagonal linear systems. The implementation of the algorithms using Computer Algebra Systems (CAS) such as MAPLE, MACSYMA, MATHEMATICA, and MATLAB are straightforward. An examples are given in order to illustrate the algorithms. The symbolic algorithm is c

Joao Gomes, Daniel Martins, Simao Melo de Sousa, Jorge Sousa Pinto

This paper introduces a proposal for a Proof Carrying Code (PCC) architecture called Lissom. Started as a challenge for final year Computing students, Lissom was thought as a mean to prove to a sceptic community, and in particular to students, that formal verification tools can be put to practice in a realistic environment, and be used to solve complex and c

Vivek V. Shende, Igor L. Markov

The three-input TOFFOLI gate is the workhorse of circuit synthesis for classical logic operations on quantum data, e.g., reversible arithmetic circuits. In physical implementations, however, TOFFOLI gates are decomposed into six CNOT gates and several one-qubit gates. Though this decomposition has been known for at least 10 years, we provide here the first d

Jean-Philippe Cointet, David Chavalarias

We propose a series of methods to represent the evolution of a field of science at different levels: namely micro, meso and macro levels. We use a previously introduced asymmetric measure of paradigmatic proximity between terms that enables us to extract structure from a large publications database. We apply our set of methods on a case study from the comple

Frédéric Guinand, Yoann Pigné

The observation and modeling of natural Complex Systems (CSs) like the human nervous system, the evolution or the weather, allows the definition of special abilities and models reusable to solve other problems. For instance, Genetic Algorithms or Ant Colony Optimizations are inspired from natural CSs to solve optimization problems. This paper proposes the us

V. B. Petkov, E. V. Bugaev, P. A. Klimai, D. V. Smirnov

Cosmic gamma-ray bursts with primary-photon energies > 10 GeV are sought in the data from the Andyrchy array obtained in the mode of detection of a single cosmic-ray component during a net observation period of 2005.4 d. The distribution of fluctuations of the detector counting rate agrees with the expected cosmic-ray background, the only exception being an

Francois Descouens, Hideaki Morita, Yasuhide Numata

We give a combinatorial proof of the factorization formula of modified Macdonald polynomials when the parameter t is specialized at a primitive root of unity. Our proof is restricted to the special case of partitions with 2 columns. We mainly use the combinatorial interpretation of Haglund, Haiman and Loehr giving the expansion of the modified Macdonald poly

Martin Kober

Gravity with incorporation of additional dimensions and noncommutative geometry.

B. Najjari, A. B. Voitkiv

We study relativistic collisions between helium-like uranium ions initially in the ground state and atoms in which, in a single collision event, one of the electrons of the ion is emitted and the other is transferred into an excited state of the residual hydrogen-like ion. We consider this two-electron process at not very high impact energies, where the acti

Z. Jiang, M. R. Pistorius

In this paper we consider the problem of pricing a perpetual American put option in an exponential regime-switching Lévy model. For the case of the (dense) class of phase-type jumps and finitely many regimes we derive an explicit expression for the value function. The solution of the corresponding first passage problem under a state-dependent level rests on

Su-Peng Kou, Michael Levin, Xiao-Gang Wen

We study several different $Z_2$ topological ordered states in frustrated spin systems. The effective theories for those different Z_2 topological orders all have the same form -- a Z_2 gauge theory which can also be written as a mutual U(1) x U(1) Chern-Simons theory. However, we find that the different Z_2 topological orders are reflected in different proj

S R Woodford, I V Barashenkov

We consider the one-dimensional anisotropic XY model in the continuum limit. Stability analysis of its Bloch wall solution is hindered by the nondiagonality of the associated linearised operator and the hessian of energy. We circumvent this difficulty by showing that the energy admits a Bogomolnyi bound in elliptic coordinates and that the Bloch wall saturat

T. Sloan, A. W. Wolfendale

A decrease in the globally averaged low level cloud cover, deduced from the ISCCP infra red data, as the cosmic ray intensity decreased during the solar cycle 22 was observed by two groups. The groups went on to hypothesise that the decrease in ionization due to cosmic rays causes the decrease in cloud cover, thereby explaining a large part of the presently

C. Alard

In the perturbative approach, substructures in the lens can be reduced to their effect on the two perturbative fields $f_1$ and $\frac{d f_0}{dθ}$. A simple generic model of elliptical lens with a substructure situated near the critical radius is investigated in details. Analytical expressions are derived for each perturbative field, and basic properties are

Nir Barnea

We study the evolution of the energy gap in a unitary Fermi gas as a function of temperature. To this end we approximate the Fermi gas by the Hubbard lattice Hamiltonian and solve using the dynamical mean-field approximation. We have found that below the critical temperature, Tc, the system is a superfluid and the energy gap is decreasing monotonously. For t

Hitoshi Konno

We propose a new realization of the elliptic quantum group equipped with the H-Hopf algebroid structure on the basis of the elliptic algebra U_{q,p}(\hat{sl}_2). The algebra U_{q,p}(\hat{sl}_2) has a constructive definition in terms of the Drinfeld generators of the quantum affine algebra U_q(\hat{sl}_2) and a Heisenberg algebra. This yields a systematic con

M. Kortelainen, J. Dobaczewski, K. Mizuyama, J. Toivanen

We show that single-particle energies in doubly magic nuclei depend almost linearly on the coupling constants of the nuclear energy density functional. Therefore, they can be very well characterized by the linear regression coefficients, which we calculate for the coupling constants of the standard Skyrme functional. We then use these regression coefficients

Juergen Vollmer

We discuss the interplay between a slow continuous drift of temperature, which induces continuous phase separation, and the non-linear diffusion term in the $ϕ^4$-model for phase separation of a binary mixture. This leads to a bound for the stability of diffusive demixing. It is argued that these findings are not specific to the $ϕ^4$ model, but that they al

Samad Khakshournia

Within our thick brane approach previously used to obtain the cosmological evolution equations on a thick brane embedded in a five-dimensional Schwarzschild Anti-de Sitter spacetime it is explicitly shown that the consistency of these equations with the energy conservation equation requires that, in general, the thickness of the brane evolves in time. This v

Ignacio de Gregorio, Etienne Mann

We show that the orbifold Chow ring of a root stack over a well-formed weighted projective space can be naturally seen as the Jacobian algebra of a function on a singular variety given by a partial compactification of its Ginzburg-Landau model.

Jean Renault

According to J. Feldman and C. Moore&#39;s well-known theorem on Cartan subalgebras, a variant of the group measure space construction gives an equivalence of categories between twisted countable standard measured equivalence relations and Cartan pairs, i.e. a von Neumann algebra (on a separable Hilbert space) together with a Cartan subalgebra. A. Kumjian ga

Patricia Boivin, Jean Renault

The classical Hausdorff-Young inequality for locally compact abelian groups states that, for $1\le p\le 2$, the $L^p$-norm of a function dominates the $L^q$-norm of its Fourier transform, where $1/p+1/q=1$. By using the theory of non-commutative $L^p$-spaces and by reinterpreting the Fourier transform, R. Kunze (1958) [resp. M. Terp (1980)] extended this ine

K. Asano, P. Mészáros

Recent observations show that hypernovae may deposit some fraction of their kinetic energy in mildly relativistic ejecta. In the dissipation process of such ejecta in a stellar wind, cosmic ray protons can be accelerated up to $\sim 10^{19}$ eV. We discuss the TeV to MeV gamma-ray and the X-ray photon signatures of cosmic rays accelerated in hypernovae. Seco

I. Weymann, J. Barnas

Electronic transport through a single-wall metallic carbon nanotube weakly coupled to one ferromagnetic and one nonmagnetic lead is analyzed in the sequential tunneling limit. It is shown that both the spin and charge currents flowing through such systems are highly asymmetric with respect to the bias reversal. As a consequence, nanotubes coupled to one nonm

C. H. Raymond Ooi

We study the effects of arbitrary laser pulse excitations on quantum correlation, entanglement and the role of quantum noise. The transient quantities are computed exactly using a method that provides exact solutions of the Langevin field operators for photon pairs produced by a double Raman atom driven by laser pulses. Short pulses with appropriate chirping

Lev P. Gor&#39;kov, Gregory B. Teitel&#39;baum

We argue that charges in underdoped La$_{2-x}$Sr$_{x}$CuO$_{4}$ move in a dissipative environment of strong spatial and temporal fluctuations. The unusual temperature dependence of the Hall angle known as &#34;the separation of lifetimes&#34; is reinterpreted and attributed to the appearance of the thermally activated component in the effective number of car

Nozomu Kawakatu, Keiichi Wada

We propose a new evolutionary model of a supermassive black hole (SMBH) and a circumnuclear disk (CND), taking into account the mass-supply from a host galaxy and the physical states of CND. In the model, two distinct accretion modes depending on gravitational stability of the CND play a key role on accreting gas to a SMBH. (i) If the CMD is gravitationally

Jayee Bhattacharya, Surajit Sengupta, Madan Rao

We study, using molecular dynamics simulations, the kinetics of shape recovery in a model solid undergoing transformations from square to a general rhombic lattice, the triangular lattice being included as a special case. We determine the necessary and sufficient conditions for such shape recovery in terms of the nature and dynamics of transient and localize

S. Twareque Ali, J. -P. Gazeau, B. Heller

We demonstrate how large classes of discrete and continuous statistical distributions can be incorporated into coherent states, using the concept of a reproducing kernel Hilbert space. Each family of coherent states is shown to contain, in a sort of duality, which resembles an analogous duality in Bayesian statistics, a discrete probability distribution and

Luis C. Ho

A significant fraction of nearby galaxies show evidence of weak nuclear activity unrelated to normal stellar processes. Recent high-resolution, multiwavelength observations indicate that the bulk of this activity derives from black hole accretion with a wide range of accretion rates. The low accretion rates that typify most low-luminosity active galactic nuc

D0 Collaboration, V. M. Abazov

We present a search for the pair production of scalar top quarks, $\tilde{t}$, using 995 pb$^{-1}$ of data collected in $p\bar{p}$ collisions with the D0 detector at the Fermilab Tevatron Collider at $\sqrt{s} = 1.96$ TeV. Both scalar top quarks are assumed to decay into a charm quark and a neutralino ($\tildeχ^{0}_{1}$), where $\tildeχ^{0}_{1}$ is the light

A. Volberg, P. Yuditskii

We consider Nehari&#39;s problem in the case of non-uniqueness of solution. The solution set is then parametrized by the unit ball of $H^{\infty}$ by means of so-called {\em regular generators} -- bounded holomorphic functions $ϕ$. The definition of {\em regularity} is given below, but let us mention now that 1) the following assumption on modulus of $ϕ$ is

Deanna Needell, Roman Vershynin

This paper seeks to bridge the two major algorithmic approaches to sparse signal recovery from an incomplete set of linear measurements -- L_1-minimization methods and iterative methods (Matching Pursuits). We find a simple regularized version of the Orthogonal Matching Pursuit (ROMP) which has advantages of both approaches: the speed and transparency of OMP

Mohamed Anber, Lorenzo Sorbo

We provide the most general embedding of a purely tensional 2-brane in a 3+1 dimensional bulk described by the AdS C-metric. The AdS C-metric has been first considered as bulk metric by Emparan, Horowitz and Myers (hep-th/9911043 and hep-th/9912135), who have found metrics describing a brane localized black hole. In those papers, one of the parameters of the

T. Maillart, D. Sornette

With the development of the Internet, new kinds of massive epidemics, distributed attacks, virtual conflicts and criminality have emerged. We present a study of some striking statistical properties of cyber-risks that quantify the distribution and time evolution of information risks on the Internet, to understand their mechanisms, and create opportunities to