May 2009 arXiv papers — page 35

Kenji Toma, Xue-Feng Wu, Peter Meszaros

The Fermi Gamma-ray Space Telescope recently detected the most energetic gamma-ray burst so far, GRB 080916C, and reported its detailed temporal properties in an extremely broad spectral range: (i) the time-resolved spectra are well described by broken power-law forms over the energy range of $10 {\rm keV}-10$ GeV, (ii) the high-energy emission (at $\epsilon

Mirjam Cvetič, Iñaki García-Etxebarria, Robert Richter

We study in detail the system of D6 branes and euclidean D2-brane instantons intersecting at angles in type IIA string theory. We find that in the absence of orientifolds the system does not contribute to the low energy superpotential, in agreement with expectations based on effective field theory arguments. We also comment on the implications of our results

Mariska Kriek, Pieter G. van Dokkum, Ivo Labbe, Marijn Franx

Several recent studies have shown that about half of the massive galaxies at z~2 are in a quiescent phase. Moreover, these galaxies are commonly found to be ultra-compact with half-light radii of ~1 kpc. We have obtained a ~29 hr spectrum of a typical quiescent, ultra-dense galaxy at z=2.1865 with the Gemini Near-Infrared Spectrograph. The spectrum exhibits

Bridget Eileen Tenner

The minimum number of elements needed for a poset to have exactly n linear extensions is at most 2sqrt{n}. In a special case, the bound can be improved to sqrt{n}.

Jeffrey S. Geronimo

A LG-WKB and Turning point theory is developed for three term recurrence formulas associated with monotonic recurrence coefficients. This is used to find strong asymptotics for certain classical orthogonal polynomials including Wilson polynomials.

Marat M. Rvachev

We suggest that the propagation of the action potential is driven by a pressure pulse propagating in the axoplasm along the axon length. The pressure pulse mechanically activates Na ion channels embedded in the axon membrane. This activation initiates the development of a local membrane voltage spike, as in the Hodgkin-Huxley model of the action potential. E

Andrey A. Shabalin, Victor J. Weigman, Charles M. Perou, Andrew B. Nobel

The search for sample-variable associations is an important problem in the exploratory analysis of high dimensional data. Biclustering methods search for sample-variable associations in the form of distinguished submatrices of the data matrix. (The rows and columns of a submatrix need not be contiguous.) In this paper we propose and evaluate a statistically

S. Bolognesi, M. Shifman, M. B. Voloshin

We consider formation of composite strings and domain walls as a result of fusion of two elementary objects (elementary strings in the first case and elementary walls in the second) located at a distance from each other. The tension of the composite object T_2 is assumed to be less than twice the tension of the elementary object T_1, so that bound states are

Michael Haack, Dieter Lust, Luca Martucci, Alessandro Tomasiello

We write down the general conditions for N=1 supersymmetric four-dimensional domain walls, deriving them from a ten-dimensional point of view using generalized complex geometry. In cases where the compactification allows for a truncation to a finite number of fields, we make contact with a four-dimensional effective description. In the context of the AdS/CFT

Nik Weaver

We propose a constructive interpretation of truth which resolves the standard semantic paradoxes.

Julio Oliva, David Tempo, Ricardo Troncoso

The theory of massive gravity in three dimensions recently proposed by Bergshoeff, Hohm and Townsend (BHT) is considered. At the special case when the theory admits a unique maximally symmetric solution, a conformally flat space that contains black holes and gravitational solitons for any value of the cosmological constant is found. For negative cosmological

Matthew Baker, Xander Faber

Let X be a tropical curve (or metric graph), and fix a base point p on X. We define the Jacobian group J(G) of a finite weighted graph G, and show that the Jacobian J(X) is canonically isomorphic to the direct limit of J(G) over all weighted graph models G for X. This result is useful for reducing certain questions about the Abel-Jacobi map Phi_p : X -> J(X)

Aynur Bulut

We prove the existence of maximizers for Strichartz inequalities for the wave equation in dimensions $d\geq 3$. Our approach follows the scheme given by Shao, which obtains the existence of maximizers in the context of the Schrödinger equation. The main tool that we use is the linear profile decomposition for the wave equation which we prove in $\mathbb{R}^d

Gong-Bo Zhao, Levon Pogosian, Alessandra Silvestri, Joel Zylberberg

Future weak lensing surveys will map the evolution of matter perturbations and gravitational potentials, yielding a new test of general relativity on cosmic scales. They will probe the relations between matter overdensities, local curvature, and the Newtonian potential. These relations can be modified in alternative gravity theories or by the effects of mass

Zeng-hui Yang, Meta van Faassen, Kieron Burke

The exact ground-state Kohn-Sham(KS) potential for the helium atom is known from accurate wavefunction calculations of the ground-state density. The threshold for photoabsorption from this potential matches the physical system exactly. By carefully studying its absorption spectrum, we show the answer to the title question is no. To address this problem in de

Ryan O. Milligan, Brian R. Dennis

This paper presents a detailed study of chromospheric evaporation using the EUV Imaging Spectrometer (EIS) onboard Hinode in conjunction with HXR observations from RHESSI. The advanced capabilities of EIS were used to measure Doppler shifts in 15 emission lines covering the temperature range T=0.05-16 MK during the impulsive phase of a C-class flare on 2007

D. Innocenti, M. Iovenitti, N. Poccia, A. Ricci

The data analysis of aftershock events of L Aquila earthquake in Apennines following the main 6.3 Mw event of April 6, 2009 has been carried out by standard statistical geophysical tools. The results show the heterogeneity of seismic activity in five different geographical sub-regions indicated by anomalous critical indices of power law distributions: the ex

J. W. Moffat

A quantum gravity theory which becomes renormalizable at short distances due to a spontaneous symmetry breaking of Lorentz invariance and diffeomorphism invariance is studied. A breaking of Lorentz invariance with the breaking patterns $SO(3,1)\to O(3)$ and $SO(3,1)\to O(2)$, describing 3+1 and 2+1 quantum gravity, respectively, is proposed. A complex time d

Shmuel Nussinov, Lian-Tao Wang, Itay Yavin

We consider the capture of dark matter in the Sun by inelastic scattering against nuclei as in the inelastic dark matter scenario. We show that, assuming a WIMP-nucleon cross-section of σ_n = 10^{-40}\cm^2 the resulting capture rate and density are sufficiently high so that current bounds on the muon neutrino flux from the Sun rule out any appreciable annihi

Nathan Chow, Justin Khoury

We study the cosmology of a galileon scalar-tensor theory, obtained by covariantizing the decoupling lagrangian of the Dvali-Gabadadze-Poratti (DGP) model. Despite being local in 3+1 dimensions, the resulting cosmological evolution is remarkably similar to that of the full 4+1-dimensional DGP framework, both for the expansion history and the evolution of den

Matthew Ballard, David Favero

We give a new upper bound for the generation time of a tilting object and use it to verify, in some new cases, a conjecture of Orlov on the Rouquier dimension of the derived category of coherent sheaves on a smooth variety.

The LIGO Scientific Collaboration, B. Abbott

According to general relativity a perturbed black hole will settle to a stationary configuration by the emission of gravitational radiation. Such a perturbation will occur, for example, in the coalescence of a black hole binary, following their inspiral and subsequent merger. At late times the waveform is a superposition of quasi-normal modes, which we refer

Shaohua Zhang

The aim of this paper is to try to establish a generic model for the problem that several multivariable number-theoretic functions represent simultaneously primes for infinitely many integral points. More concretely, we introduced briefly the research background-the history and current situation-from Euclid's second theorem to Green-Tao theorem. We analy

Ignacio Cernuda

Recent results from the PAMELA, ATIC, PPB BETS and Fermi collaborations extend the energy range in the electron flux measurement up to unexplored energies in the hundred GeVs range confirming the bump starting at about 10GeV already suggested by HEAT and AMS01 data . This bump can be explained by annihilating dark matter in the context of exotic physics, or

Egor Shelukhin

In this note the interrelations between several natural morphisms on the $π_1$ of groups of Hamiltonian diffeomorphisms are investigated. As an application, the equality of the (non-linear) Maslov index of loops of quantomorphisms of prequantizations of $\C P^n$ and the Calabi-Weinstein invariant is shown, settling affirmatively a conjecture by A. Givental.

B. A. Kniehl, A. V. Kotikov, Z. V. Merebashvili, O. L. Veretin

We consider the production of heavy-quark pairs in the collisions of polarized and unpolarized on-shell photons and present, in analytic form, the fully integrated total cross sections for total photon spins $J_z=0, \pm 2$ at next-to-leading-order in QCD. Phenomenological applications include $b\bar b$ production, which represents an irreducible background t

T. S. Biró, P. Ván

Relativistic thermodynamics is constructed from the point of view of special relativistic hydrodynamics. A relativistic four-current for heat and a general treatment of thermal equilibrium between moving bodies is presented. The different temperature transformation formulas of Planck and Einstein, Ott, Landsberg and Doppler appear upon particular assumptions

Luca Pagano, Paolo de Bernardis, Grazia De Troia, Giulia Gubitosi

Cosmic Microwave Background experiments must achieve very accurate calibration of their polarization reference frame to avoid biasing the cosmological parameters. In particular, a wrong or inaccurate calibration might mimic the presence of a gravitational wave background, or a signal from cosmological birefringence, a phenomenon characteristic of several non

Zuoliang Hou

In this paper, we studied integrals involving both real and complex Hessian operators over bounded domain. Poincare type inequalities were proved in both cases which generalized a early results of Trudinger and Wang.

Shiqian Ma, Donald Goldfarb, Lifeng Chen

The linearly constrained matrix rank minimization problem is widely applicable in many fields such as control, signal processing and system identification. The tightest convex relaxation of this problem is the linearly constrained nuclear norm minimization. Although the latter can be cast as a semidefinite programming problem, such an approach is computation

Jean-Marc Couveignes, Reynald Lercier

We present a randomized algorithm that on input a finite field $K$ with $q$ elements and a positive integer $d$ outputs a degree $d$ irreducible polynomial in $K[x]$. The running time is $d^{1+ε(d)} \times (\log q)^{5+ε(q)}$ elementary operations. The function $ε$ in this expression is a real positive function belonging to the class $o(1)$, especially, the c

Maikel C. Rheinstadter

Neutrons and x-rays are coherent probes, and their coherent properties are used in scattering experiments. Only coherent scattering probes can elucidate collective molecular motions. While phonons in crystals were studied for half a century now, the study of collective molecular motions in soft-matter and biology is a rather new but upcoming field. Collectiv

Krzysztof Pachucki

We present an efficient approach to evaluate two-center two-electron integrals with exponential functions and with an arbitrary polynomial in electron-nucleus and electron-electron distances. We show that the master integral with the single negative power of all distances can be obtained from the second order differential equation in $r$, the distance betwee

Takayuki Kobo, Yutaka Matsuo, Shotaro Shiba

In our previous paper, it was shown that BLG model based on a Lorentzian metric 3-algebra gives Dp-brane action whose worldvolume is compactified on torus T^d (d=p-2). Here the 3-algebra was a generalized one with d+1 pairs of Lorentzian metric generators and expressed in terms of a loop algebra with central extensions. In this paper, we derive the precise r

P. Reznicek

An overview of ATLAS and CMS studies of B_s leptonic decays providing constraints on the lepton flavour violation phenomenon is presented. Except direct lepton flavour violating final states B_s -> l_1^+ l_2^-, constraints can also be set by a measurement of B_s -> mu^+ mu^- decay, whose branching ratio in some theoretical models correlates with a branching

Helmut G. Katzgraber

Monte Carlo methods play an important role in scientific computation, especially when problems have a vast phase space. In this lecture an introduction to the Monte Carlo method is given. Concepts such as Markov chains, detailed balance, critical slowing down, and ergodicity, as well as the Metropolis algorithm are explained. The Monte Carlo method is illust

Helmut G. Katzgraber

Writing complex computer programs to study scientific problems requires careful planning and an in-depth knowledge of programming languages and tools. In this chapter the importance of using the right tool for the right problem is emphasized. Common tools to organize computer programs, as well as to debug and improve them are discussed, followed by simple da

P. Marios Petropoulos, Nikolaos Prezas, Konstadinos Sfetsos

We consider certain classes of operators in the exact conformal field theory SL(2,R) x SU(2) x U(1)^4 describing strings in an AdS(3) x S(3) x T4 geometry supported by Neveu--Schwarz 3-form fluxes. This background arises in the near-horizon limit of a system of NS5-branes wrapped on a 4-torus and F1-branes smeared on the 4-torus when both types of branes are

Paul Smyth, Silvia Vaulà

We study supersymmetric domain wall solutions in four dimensions arising from the compactification of type II supergravity on a SU(3)xSU(3) structure manifold. Using a pure spinor approach, we show that the supersymmetry variations can be reinterpreted as a generalisation of the Hitchin flow equations and describe the embedding of a SU(3)xSU(3) structure man

Patrick Das Gupta

We consider the dynamics of a four-form field $\tilde {w} $, treating it as a distinct physical degree of freedom, independent of the metric. The equations of motion are derived from an action which, besides having the standard Hilbert-Einstein term and the matter part, consists of a new action for $\tilde {w} $. The evolution of $\tilde {w} $ in a flat FRW

Lucas Fresse, Anna Melnikov

Let ${\mathcal B}_u$ be the Springer fiber over a nilpotent endomorphism $u\in End(\mathbb{C}^n)$. Let $J(u)$ be the Jordan form of $u$ regarded as a partition of $n$. The irreducible components of ${\mathcal B}_u$ are all of the same dimension. They are labelled by Young tableaux of shape $J(u)$. We study the question of singularity of the components of ${\

E. R. Bezerra de Mello

In this paper we analyse the vacuum polarization effects associated with massive scalar quantum fields in a higher-dimensional de Sitter space in the presence of a global monopole. Because this analysis has been developed in a pure de Sitter space, here we are mainly interested on the effects induced by the presence of the global monopole. So, in order to ac

Kosmas L. Tsakmakidis, Marek S. Wartak, Durga P. Aryal, Ortwin Hess

A well-known principle in optical physics states that power can never be exchanged between two light waves propagating inside a homogeneous medium when the medium response is strictly linear. Power exchange between light waves usually occurs with the aid of nonlinearity. A typical example is nonlinear optical parametric amplification where net energy can flo

T. Lindstrom, J. E. Healey, M. S. Colclough, C. M. Muirhead

Planar superconducting resonators are now being increasingly used at mK temperatures in a number of novel applications. They are also interesting devices in their own right since they allow us to probe the properties of both the superconductor and its environment. We have experimentally investigated three types of niobium resonators - including a lumped elem

Erkko Lehtonen, Ágnes Szendrei

For each clone C on a set A there is an associated equivalence relation analogous to Green's R-relation, which relates two operations on A iff each one is a substitution instance of the other using operations from C. We study the clones for which there are only finitely many relative R-classes.

D0 Collaboration, V. Abazov

We search for a new light gauge boson, a dark photon, with the D0 experiment. In the model we consider, supersymmetric partners are pair produced and cascade to lightest neutralinos that can decay into the hidden sector state plus either a photon or a dark photon. The dark photon decays through its mixing with a photon into fermion pairs. We therefore invest

M. Maturi, C. Mignone

We define an optimal basis system into which cosmological observables can be decomposed. The basis system can be optimised for a specific cosmological model or for an ensemble of models, even if based on drastically different physical assumptions. The projection coefficients derived from this basis system, the so-called features, provide a common parameteris

Kuniyasu Saitoh, Hisao Hayakawa

Depositions of amorphous Lennard-Jones clusters on a crystalline surface are numerically investigated. From the results of the molecular dynamics simulation, we found that the deposited clusters exhibit a transition from multilayered adsorption to monolayered adsorption at a critical incident speed. Employing the energy conservation law, we can explain the b

Alessandra Corsi, Dafne Guetta, Luigi Piro

We investigate whether the high energy tail detected by the Fermi/LAT for the short GRB 081024B can be caused by synchrotron and self-Compton emission in the context of either the internal or external shock models. For the internal shock scenario, we explore the possibility of generating the high energy photons directly by means of the synchrotron process, o

O. Bertolami, J. Paramos, P. Santos

We use stellar dynamics arguments to constrain the relevant parameters of ungravity inspired models. We show that resulting bounds do constrain the parameters of the theory of unparticles, as far as its energy scale satisfies the condition $Λ\geq 1 TeV$ and $d$ is close to unity.

P. Roy Chowdhury, D. N. Basu, C. Samanta

The density dependence of nuclear symmetry energy is determined from a systematic study of the isospin dependent bulk properties of asymmetric nuclear matter using the isoscalar and the isovector components of density dependent M3Y interaction. The incompressibility $K_\infty$ for the symmetric nuclear matter, the isospin dependent part $K_{asy}$ of the isob

Insong Choe, George H. Hitching

For a vector bundle V over a curve X of rank n and for each integer r in the range 1 \le r \le n-1, the Segre invariant s_r is defined by generalizing the minimal self-intersection number of the sections on a ruled surface. In this paper we generalize Lange and Narasimhan's results on rank 2 bundles which related the invariant s_1 to the secant varieties

Gabriel P. Paternain

Let $M$ be a closed orientable surface of negative curvature. A connection is said to be transparent if its parallel transport along closed geodesics is the identity. We describe all transparent SU(2)-connections and we show that they can be built up from suitable Bäcklund transformations.

T. M. Aliev, K. O. Ozansoy

We investigate the single top quark production with the exchange of unparticles through high energy photon-photon collision $γγ\to t \bar c$. The effects of unparticles on the scattering cross sections for different polarization configurations, and for various values of the scaling dimension $d, 1<d<2$ are analysed. It is shown that the $(+-)$ polarisation c

A. E. Allahverdyan, B. Mehmani

We study a slow classical system [particle] coupled to a fast quantum system with discrete energy spectrum. We adiabatically exclude the quantum system and construct an autonomous dynamics for the classical particle in successive orders of the small ratio $ε$ of the characteristic times. It is known that in the order $ε^0$ the particle gets an additional [Bo

L. Mahy, Y. Naze, G. Rauw, E. Gosset

Aims. We present the results obtained from a long-term spectroscopic campaign devoted to the multiplicity of O-type stars in the young open cluster NGC2244 and in the Mon OB2 association. Methods. Our spectroscopic monitoring was performed over several years, allowing us to probe different time-scales. For each star, several spectral diagnostic tools are app

Ferran Valdez

We describe Veech groups of flat surfaces arising from irrational angled polygonal billiards or irreducible stable abelian differentials. For irrational polygonal billiards, we prove that these groups are non-discrete subgroups of SO(2,R) and we calculate their rank.

Dominik Scheder

We call a CNF formula linear if any two clauses have at most one variable in common. We show that there exist unsatisfiable linear k-CNF formulas with at most 4k^2 4^k clauses, and on the other hand, any linear k-CNF formula with at most 4^k/(8e^2k^2) clauses is satisfiable. The upper bound uses probabilistic means, and we have no explicit construction comin

H. Kurtze, D. R. Yakovlev, D. Reuter, A. D. Wieck

The population dynamics of dark and bright excitons in (In,Ga)As/GaAs quantum dots is studied by two-color pump-probe spectroscopy in an external magnetic field. With the field applied in Faraday geometry and at T<20 K, the dark excitons decay on a ten nanoseconds time scale unless the magnetic field induces a resonance with a bright exciton state. At these

Lapo Casetti, Michael Kastner, Rachele Nerattini

In contrast to the canonical case, microcanonical thermodynamic functions can show nonanalyticities also for finite systems. In this paper we contribute to the understanding of these nonanalyticities by working out the relation between nonanalyticities of the microcanonical entropy and its configurational counterpart. If the configurational microcanonical en

Holger F. Hofmann, Hitoshi Nishitani

Ideally, strong non-linearities could be used to implement quantum gates for photonic qubits by well controlled two photon interactions. However, the dependence of the non-linear interaction on frequency and time makes it difficult to preserve a coherent pulse shape that could justify a single mode model for the time-frequency degree of freedom of the photon

Vincent Tisserand

We present the status of the CKM matrix parameters in the framework of the Standard Model. We perform a model independent analysis to set constraints on additional effective parameters accounting for possible New Physics effects and to evaluate the present allowed space for these effects both from $B_d$ and $B_s$ mesons.

Dan Ben-Yaakov, David Andelman, Daniel Harries, Rudi Podgornik

The Poisson-Boltzmann mean-field description of ionic solutions has been successfully used in predicting charge distributions and interactions between charged macromolecules. While the electrostatic model of charged fluids, on which the Poisson-Boltzmann description rests, and its statistical mechanical consequences have been scrutinized in great detail, muc

C. Lippmann

ALICE is a general-purpose heavy-ion detector at the CERN LHC. We describe the commissioning activities in the years 2007-2009 and the status of the different subsystems at the time of this conference.

BES Collaboration

Using a sample of 58 million $J/ψ$ events collected with the BESII detector at the BEPC, more than 100,000 $J/ψ\to p\bar p π^0$ events are selected, and a detailed partial wave analysis is performed. The branching fraction is determined to be $Br(J/ψ\to p \bar p π^0)=(1.33 \pm 0.02 \pm 0.11) \times 10^{-3}$. A long-sought `missing&#39; $N^*$, first observed

S. S. Zilitinkevich, T. Elperin, N. Kleeorin, V. L&#39;vov

We advance our prior energy- and flux-budget turbulence closure model (Zilitinkevich et al., 2007, 2008) for the stably stratified atmospheric flows and extend it accounting for additional vertical flux of momentum and additional productions of turbulent kinetic energy, turbulent potential energy (TPE) and turbulent flux of potential temperature due to large

Xin-Heng Guo, Ming-Yang Huang, Bing-Lin Young

In this paper, we first discuss the detection of supernova neutrino on Earth. Then we propose a possible method to acquire information about $\theta_{13}$ smaller than $1.5^\circ$ by detecting the ratio of the event numbers of different flavor supernova neutrinos. Such an sensitivity cannot yet be achieved by the Daya Bay reactor neutrino experiment.

Etsuko Kawakami, Masahiro Kawasaki, Kazunori Nakayama, Fuminobu Takahashi

Non-Gaussianity may exist in the CDM isocurvature perturbation. We provide general expressions for the bispectrum and trispectrum of both adiabatic and isocurvature pertubations. We apply our result to the QCD axion case, and found a consistency relation between the coefficients of the bispectrum and trispectrum : tau_{NL}^(iso)~10^3 [f_{NL}^(iso)]^{4/3}, if

Freddy Bouchet, Hidetoshi Morita

We study the asymptotic behavior and the asymptotic stability of the two-dimensional Euler equations and of the two-dimensional linearized Euler equations close to parallel flows. We focus on spectrally stable jet profiles $U(y)$ with stationary streamlines $y_{0}$ such that $U&#39;(y_{0})=0$, a case that has not been studied previously. We describe a new dy

Zhisu Zhu, Anthony Man-Cho So, Yinyu Ye

Motivated by the philosophy and phenomenal success of compressed sensing, the problem of reconstructing a matrix from a sampling of its entries has attracted much attention recently. Such a problem can be viewed as an information-theoretic variant of the well-studied matrix completion problem, and the main objective is to design an efficient algorithm that c

Er-Cheng Tsai

We propose moving all the $γ_{5}$ matrices to the rightmost position before continuing the dimension, and show that this simple prescription will enable the dimension regularization scheme proposed by &#39;t Hooft and Veltman to be consistent with gauge invariance.

Wei-Bo Gao, Austin G. Fowler, Robert Raussendorf, Xing-Can Yao

Topological error correction--a novel method to actively correct errors based on cluster states with topological properties--has the highest order of tolerable error rates known to date (10^{-2}). Moreover, the scheme requires only nearest-neighbour interaction, particularly suitable for most physical systems. Here we report the first experimental demonstrat

Yuma Kikuchi, Takayuki Myo, Masaaki Takashina, Kiyoshi Kato

We propose a new method to describe three-body breakups of nuclei, in which the Lippmann-Schwinger equation is solved combining with the complex scaling method. The complex-scaled solutions of the Lippmann-Schwinger equation (CSLS) enables us to treat boundary conditions of many-body open channels correctly and to describe a many-body breakup amplitude from

Yunjiang Jiang

We show that the classical Kac&#39;s random walk on $(n-1)$-sphere $S^{n-1}$ starting from the point mass at $e_1$ mixes in $\mathcal{O}(n^5(\log n)^3)$ steps in total variation distance. The main argument uses a truncation of the running density after a burn-in period, followed by $\mathcal{L}^2$ convergence using the spectral gap information derived by oth

Ichiro Oda

We consider renormalizability of topologically massive gravity in three space-time dimensions. With a usual parametrization of the metric tensor, we establish the statement that topologically massive gravity is in fact renormalizable. In this proof, we make use of not only a recently found, new infrared regularization method of scalar mode but also a covaria

E. Pereira, F. Moraes

We study light scattering by a hedgehog-like and linear disclination topological defects in a nematic liquid crystal by a metric approach. Light propagating near such defects feels an effective metric equivalent to the spatial part of the global monopole and cosmic string geometries. We obtain the scattering amplitude and the differential and total scatterin

Dorin Ghisa

Global mapping properties of the Riemann Zeta function are used to investigate its non trivial zeros.

Yuu Niino, Tomonori Totani, Masakazu A. R. Kobayashi

Long gamma-ray bursts (GRBs) have been suggested to occur preferentially in low metallicity environment. We discuss the possibility and theoretical aspects of using Lyman alpha emission properties of long GRB host galaxies as a metallicity indicator of high redshift GRB environments, where direct metallicity measurements are not easy. We propose to use the f

R. A. Konoplya

Recently a renormalizable model of gravity has been proposed, which might be a UV completion of General Relativity (GR) or its infra-red modification, probably with a strongly coupled scalar mode. Although the generic vacuum of the theory is anti-de Sitter one, particular limits of the theory allow for the Minkowski vacuum. In this limit (though without cons

Seokcheon Lee, Kin-Wang Ng

We obtain the exact analytic form of the growth index at present epoch ($a=1$) in a flat universe with the cosmological constant ({\it i.e.} the dark energy with its equation of state $ω_{de} = -1$). For the cosmological constant, we obtain the exact value of the current growth index parameter $γ= 0.5547$, which is very close to the well known value 6/11. We

Zhongzhi Zhang, Wenlei Xie, Shuigeng Zhou, Shuyang Gao

It is known that the heterogeneity of scale-free networks helps enhancing the efficiency of trapping processes performed on them. In this paper, we show that transport efficiency is much lower in a fractal scale-free network than in non-fractal networks. To this end, we examine a simple random walk with a fixed trap at a given position on a fractal scale-fre

Terry A. Loring

The noncommutative analog of an approximative absolute retract (AAR) is introduced, a weakly projective C*-algebra. This property sits between being residually finite dimensional and projectivity. Examples and closure properties are considered.

Ryan Kinser

For each positive integer $n \geq 4$, we give an inequality satisfied by rank functions of arrangements of $n$ subspaces. When $n=4$ we recover Ingleton&#39;s inequality; for higher $n$ the inequalities are all new. These inequalities can be thought of as a hierarchy of necessary conditions for a (poly)matroid to be realizable. Some related open questions ab

Victor M. Yakovenko, J. Barkley Rosser

This Colloquium reviews statistical models for money, wealth, and income distributions developed in the econophysics literature since the late 1990s. By analogy with the Boltzmann-Gibbs distribution of energy in physics, it is shown that the probability distribution of money is exponential for certain classes of models with interacting economic agents. Alter

C. Ortix, J. Lorenzana, C. Di Castro

We derive the phase diagram of a paradigmatic model of Coulomb frustrated phase separation in two-dimensional systems with negative short-range electronic compressibility. We consider the system subject either to the truly three-dimensional long-range Coulomb interaction (LRC) and to a two-dimensional LRC with logarithmic-like behavior. In both cases we find

J. Czyzowicz, S. Dobrev, L. Gasieniec, D. Ilcinkas

We consider the problem of periodic graph exploration in which a mobile entity with constant memory, an agent, has to visit all n nodes of an arbitrary undirected graph G in a periodic manner. Graphs are supposed to be anonymous, that is, nodes are unlabeled. However, while visiting a node, the robot has to distinguish between edges incident to it. For each

K. Paudel, M. Chandrasekhar, S. Guha

Polyfluorenes (PFs) represent a unique class of poly para-phenylene based blue-emitting polymers with intriguing structure-property relationships. Slight variations in the choice of functionalizing side chains result in dramatic differences in the inter- and intra-chain structures in PFs. We present photoluminescence (PL) and Raman scattering studies of bulk

Hsiang-Ku Lin, Leonid P. Pryadko, Sharon Walker, Roya Zandi

We study the transport and deposition dynamics of colloids in saturated porous media under unfavorable filtering conditions. As an alternative to traditional convection-diffusion or more detailed numerical models, we consider a mean-field description in which the attachment and detachment processes are characterized by an entire spectrum of rate constants, r

Cheng-Wei Qiu, Li Hu, Baile Zhang, Bae-Ian Wu

Two novel classes of spherical invisibility cloaks based on nonlinear transformation have been studied. The cloaking characteristics are presented by segmenting the nonlinear transformation based spherical cloak into concentric isotropic homogeneous coatings. Detailed investigations of the optimal discretization (e.g., thickness control of each layer, nonlin

C. Caceres, V. D. Ivanov, D. Minniti, D. Naef

Currently the only technique sensitive to Earth mass planets around nearby stars (that are too close for microlensing) is the monitoring of the transit time variations of the transiting extrasolar planets. We search for additional planets in the systems of the hot Neptune GJ 436b, and the hot-Jupiter XO-1b, using high cadence observations in the J and Ks ban

Nikolaos Diamantis, Peter Kleban

We consider the three new crossing probabilities for percolation recently found via conformal field theory by Simmons, Kleban and Ziff. We prove that all three of them (i) may be simply expressed in terms of Cardy&#39;s and Watts&#39; crossing probabilities, (ii) are (weakly holomorphic) second-order modular forms of weight 0 (and a single particular type) o

Myung-Ho Bae, Robert C. Dinsmore, Thomas Aref, Matthew Brenner

Quantum phase slippage (QPS) in a superconducting nanowire is a new candidate for developing a quantum bit. It has also been theoretically predicted that the occurrence of QPS significantly changes the current-phase relationship (CPR) of the wire due to the tunneling between topologically different metastable states. We present studies on the microwave respo

Renzo Cavalieri, Gueorgui Todorov

We study the relation among the genus 0 Gromov-Witten theories of the three spaces $\mathcal{X}\leftarrow\mathcal{Z}\leftarrow Y$, where $\mathcal{X}=[\c^2/\z_3]$, $\mathcal{Z}$ is obtained by a weighted blowup at the stacky point of $\mathcal{X}$, and $Y$ is the crepant resolution of the $A_2$ singularity. We formulate and verify a statement similar to the

Pawel Kurzynski, Wawrzyniec Kaszub, Mikolaj Czechlewski

The two observables are complementary if they cannot be measured simultaneously, however they become maximally complementary if their eigenstates are mutually unbiased. Only then the measurement of one observable gives no information about the other observable. The spin projection operators onto three mutually orthogonal directions are maximally complementar

Vitaly V. Ganusov, Daniel L. Barber, Rob J. De Boer

It has been difficult to measure efficacy of T cell-based vaccines and to correlate efficacy of CD8$^+$T cell responses with protection against viral infections. In part, this difficulty is due to our poor understanding of the in vivo efficacy of CD8$^+$T cells. Using a recently developed experimental method of in vivo cytotoxicity we investigated quantitati

W. van Driel, S. E. Schneider, R. C. Kraan-Korteweg, D. Monnier Ragaigne

A pilot survey has been made to obtain 21cm HI emission line profiles for 197 objects in the Zone of Avoidance (ZoA) that were classified as galaxies in the 2MASS all-sky near-infrared Extended Source Catalog (2MASX). 116 of the sources were observed using the Nancay radio telescope, in the 325 to 11,825 km/s range, and the other 81 sources were observed at

W. Hebisch, B. Zegarlinski

We study coercive inequalities on finite dimensional metric spaces with probability measures which do not have volume doubling property. This class of inequalities includes Poincaré and Log-Sobolev inequality. Our main result is proof of Log-Sobolev inequality on Heisenberg group equipped with either heat kernel measure or &#34;gaussian&#34; density build fr

A. L. Sakhnovich, A. A. Karelin, J. Seck-Tuoh-Mora, G. Perez-Lechuga

Explicit inversion formulas for a subclass of integral operators with $D$-difference kernels on a finite interval are obtained. A case of the positive operators is treated in greater detail. An application to the inverse problem to recover canonical system from a Weyl function is given.

LIGO Scientific Collaboration

This paper reports on an all-sky search for periodic gravitational waves from sources such as deformed isolated rapidly-spinning neutron stars. The analysis uses 840 hours of data from 66 days of the fifth LIGO science run (S5). The data was searched for quasi-monochromatic waves with frequencies f in the range from 50 Hz to 1500 Hz, with a linear frequency

D. Blas, D. Comelli, F. Nesti, L. Pilo

A systematic study of the different phases of Lorentz-breaking massive gravity in a curved background is performed. For tensor and vector modes, the analysis is very close to that of Minkowski space. The most interesting results are in the scalar sector where, generically, there are two propagating degrees of freedom (DOF). While in maximally symmetric space