May 2010 arXiv papers — page 5

Chiara Caprini

First order phase transitions in the early universe can give rise to a stochastic background of gravitational waves. A hypothetical first order electroweak phase transition is particularly interesting in this respect, since the signal is in the good frequency range to be detectable by the space interferometer LISA. Three main processes lead to the production

Christian Scimiterna, Decio Levi

In this paper we are extending the well known integrability theorems obtained by multiple scale techniques to the case of linearizable difference equations. As an example we apply the theory to the case of a differential-difference dispersive equation of the Burgers hierarchy which via a discrete Hopf-Cole transformation reduces to a linear differential diff

Christina V. Kraus, J. Ignacio Cirac

We present numerical methods to solve the Generalized Hartree-Fock theory for fermionic systems in lattices, both in thermal equilibrium and out of equilibrium. Specifically, we show how to determine the covariance matrix corresponding to the Fermionic Gaussian state that optimally approximates the quantum state of the fermions. The methods apply to relative

Frank Aurzada, Sergej Beck, Michael Scheutzow

We consider a general polling model with $N$ stations. The stations are served exhaustively and in cyclic order. Once a station queue falls empty, the server does not immediately switch to the next station. Rather, it waits at the station for the possible arrival of new work ("wait-and-see") and, in the case of this happening, it restarts service in

Elena Guardo, Adam Van Tuyl

Let Z be a set of fat points in P^1 x P^1 that is also arithmetically Cohen-Macaulay (ACM). We describe how to compute the degree of a separator of a fat point of multiplicity m for each point in the support of Z using only a numerical description of Z. Our formula extends the case of reduced points which was previously known.

Peter A. Jonsson, Johan Nordlander

Previous deforestation and supercompilation algorithms may introduce accidental termination when applied to call-by-value programs. This hides looping bugs from the programmer, and changes the behavior of a program depending on whether it is optimized or not. We present a supercompilation algorithm for a higher-order call-by-value language and prove that the

Ram Brustein, A. J. M. Medved

We discuss corrections to the ratio of shear viscosity to entropy density $η/s$ in higher-derivative gravity theories. Generically, these theories contain ghost modes with Planck-scale masses. Motivated by general considerations about unitarity, we propose new boundary conditions for the equations of motion of the graviton perturbations that force the amplit

Tomonari Sei, Nobuki Takayama, Akimichi Takemura, Hiromasa Nakayama

We give a new algorithm to find local maximum and minimum of a holonomic function and apply it for the Fisher-Bingham integral on the sphere $S^n$, which is used in the directional statistics. The method utilizes the theory and algorithms of holonomic systems.

David Kalaj

Let $A$ and $A'$ be two circular annuli and let $ρ$ be a radial metric defined in the annulus $A'$. Consider the class $\mathcal H_ρ$ of $ρ-$harmonic mappings between $A$ and $A'$. It is proved recently by Iwaniec, Kovalev and Onninen that, if $ρ=1$ (i.e. if $ρ$ is Euclidean metric) then $\mathcal H_ρ$ is not empty if and only if there holds the

M. Shifman, A. Yung

We consider N=2 supersymmetric QCD with the U(N) gauge group (with no Fayet-Iliopoulos term) and N_f flavors of massive quarks deformed by the mass term μfor the adjoint matter, W=μA^2, assuming that N\leq N_f<2N. This deformation breaks N=2 supersymmetry down to N=1. This theory supports non-Abelian flux tubes (strings) which are stabilized by W. They are r

Alexandr Kazantsev

In a recent work &#34;Arc-presentation of links: Monotonic simplification&#34; Ivan Dynnikov showed that each rectangular diagram of the unknot, composite link, or split link can be monotonically simplified into a trivial, composite, or split diagram, respectively. The following natural question arises: Is it always possible to simplify monotonically a recta

James M. Chappell, Azhar Iqbal, Derek Abbott

We construct quantum games from a table of non-factorizable joint probabilities, coupled with a symmetry constraint, requiring symmetrical payoffs between the players. We give the general result for a Nash equilibrium and payoff relations for a game based on non-factorizable joint probabilities, which embeds the classical game. We study a quantum version of

Esteban Meca, Laureano Ramirez-Piscina

We study the convective instability of the melt during the initial transient in a directional solidification experiment in a vertical configuration. We obtain analytically the dispersion relation, and perform an additional asymptotic expansion for large Rayleigh number that permits a simpler analytical analysis and a better numerical behavior. We find a tran

Andrew D. Gilbert, Yannick Ponty, Vladislav Zheligovsky

This paper considers magnetic field generation by a fluid flow in a system referred to as the Archontis dynamo: a steady nonlinear magnetohydrodynamic (MHD) state is driven by a prescribed body force. The field and flow become almost equal and dissipation is concentrated in cigar-like structures centred on straight-line separatrices. Numerical scaling laws f

Kobi Barkan, Haim Diamant, Ron Lifshitz

Quasicrystals whose building blocks are of mesoscopic rather than atomic scale have recently been discovered in several soft-matter systems. Contrary to metallurgic quasicrystals whose source of stability remains a question of great debate to this day, we argue that the stability of certain soft-matter quasicrystals can be directly explained by examining a c

Theodoros Diakonidis, Bas Tausk

This study is targeted to the NLO corrections of multileg processes, very important for the LHC. Starting from the construction of Feynman diagrams, the analytical reduction of general one-loop integrals to scalar master ones, the calculation of color structures, manipulation of spinor lines and other amplitude constituents and finally phase space point sele

Xiong Jin

We prove a Hausdorff dimension result for the image of two-dimensional multiplicative cascade processes, and we obtain from this result a KPZ-type formula which normally has one point of phase transition.

Maxim V. Barkov, Felix A. Aharonian, Valenti Bosch-Ramon

Non-blazar AGN have been recently established as a class of gamma-ray sources. M87, a nearby representative of this class, show fast TeV variability on timescales of a few days. We suggest a scenario of flare gamma-ray emission in non-blazar AGN based on a red giant interacting with the jet at the base. We solve the hydrodynamical equations that describe the

Michael R. Bareford, Philippa. K. Browning, Ronald A. M. Van der Linden

Context: It is thought likely that vast numbers of nanoflares are responsible for the corona having a temperature of millions of degrees. Current observational technologies lack the resolving power to confirm the nanoflare hypothesis. An alternative approach is to construct a magnetohydrodynamic coronal loop model that has the ability to predict nanoflare en

V. Yu. Irkhin

A scaling consideration of the Kondo lattices is performed with account of logarithmic Van Hove singularities (VHS) in the electron density of states. The scaling trajectories are presented for different magnetic phases. It is demonstrated that VHS lead to a considerable increase of the non-Fermi-liquid behavior region owing to softening of magnon branches d

TAPS Collaboration, M. Nanova, V. Metag, G. Anton

Data on the photoproduction of $ω$ mesons on nuclei have been re-analyzed in a search for in-medium modifications. The data were taken with the Crystal Barrel(CB)/TAPS detector system at the ELSA accelerator facility in Bonn. First results from the analysis of the data set were published by D. Trnka et al. in Phys. Rev. Lett 94 (2005) 192303 \cite{david}, cl

Qian Lin

In this paper, we deal with one dimensional backward doubly stochastic differential equations (BDSDEs) where the coefficient is left Lipschitz in y (may be discontinuous) and uniformly continuous in z. We obtain a generalized comparison theorem and a generalized existence theorem of BDSDEs .

Angel Garcimartin, Iker Zuriguel, Luis A. Pugnaloni, Alvaro Janda

We present experimental results on the shape of arches that block the outlet of a two dimensional silo. For a range of outlet sizes, we measure some properties of the arches such as the number of particles involved, the span, the aspect ratio, and the angles between mutually stabilizing particles. These measurements shed light on the role of frictional tange

Roi Levy, Yigal Meir

The quantum Hall transition is one of the simplest and most studied quantum phase transitions. Nevertheless, the experimental observation of a new phase in this regime, the quantum Hall insulator, still remains a puzzle since the first report more than a decade ago, as it is in contradiction with all theoretical studies based on microscopically coherent quan

Dov Gabbay, Karl Schlechta

In this work in progress, we discuss independence and interpolation and related topics for classical, modal, and non-monotonic logics.

S. Maier, A. Komnik

We analyze the transport properties of a quantum dot with a harmonic degree of freedom (Holstein phonon) coupled to interacting one-dimensional metallic leads. Using Tomonaga-Luttinger model to describe the interacting leads we construct the generating function of the full counting statistics (FCS) for a specific constellation of system parameters and give e

Svenja Glied

The groups of (linear) similarity and coincidence isometries of certain modules in d-dimensional Euclidean space, which naturally occur in quasicrystallography, are considered. It is shown that the structure of the factor group of similarity modulo coincidence isometries is the direct sum of cyclic groups of prime power orders that divide d. In particular, i

Somshubhro Bandyopadhyay, Ramij Rahaman, William K. Wootters

The &#34;entanglement cost&#34; of a bipartite measurement is the amount of shared entanglement two participants need to use up in order to carry out the given measurement by means of local operations and classical communication. Here we numerically investigate the entanglement cost of generic orthogonal measurements on two qubits. Our results strongly sugge

Michael Kohlhase, Florian Rabe, Vyacheslav Zholudev

MKM has been defined as the quest for technologies to manage mathematical knowledge. MKM &#34;in the small&#34; is well-studied, so the real problem is to scale up to large, highly interconnected corpora: &#34;MKM in the large&#34;. We contend that advances in two areas are needed to reach this goal. We need representation languages that support incremental

J. -P. Bocquet, D. Moricciani, V. Bellini, M. Beretta

The possibility of anisotropies in the speed of light relative to the limiting speed of electrons is considered. The absence of sidereal variations in the energy of Compton-edge photons at the ESRF&#39;s GRAAL facility constrains such anisotropies representing the first non-threshold collision-kinematics study of Lorentz violation. When interpreted within th

Xiaohong Zhao, Zhuo Li, Jinming Bai

The Lorentz factor (LF) of gamma-ray burst (GRB) ejecta may be constrained by observations of high-energy (HE) spectral attenuation. The recent Fermi-LAT observations of prompt GeV emission from several bright GRBs have leaded to conclusions of unexpectedly large LFs, $Γ>10^3$. Here we revisit this problem with two main concerns. (1) With one-zone assumption

Erich Gaertig, Kostas D. Kokkotas

We investigate damping and growth times of the f-mode for rapidly rotating stars and a variety of different polytropic equations of state in the Cowling approximation. We discuss the differences in the eigenfunctions of co- and counterrotating modes and compute the damping times of the f-mode for several EoS and all rotation rates up to the Kepler-limit. Thi

Jing Lu, Lan Zhou, H. C. Fu, Le-Man Kuang

Decoherence for a one-dimensional coupled-resonator waveguide with a two-level system inside one of resonators, induced by their interaction with corresponding environments, is investigated. Each environment is modeled as a continuum of harmonic oscillators. By finding the eigenstates of the hybrid system, which is the dressed state of the hybrid system, we

A. A. Perov, L. V. Solnyshkova, D. V. Khomitsky

The terahertz radiation-induced conductivity and dielectric polarization tensors as well as the Faraday and Kerr rotation angles and the non-equilibrium spin textures are studied for two-dimensional electron gas with strong spin-orbit coupling subjected to high magnetic field and to tunable periodic potential of a two-dimensional gated superlattice. It is fo

Ishwar Dutt, Rajeev K. Puri

Using the three versions of proximity potentials, namely proximity 1977, proximity 1988, and proximity 2000, we present a pocket formula for fusion barrier heights and positions. This was achieved by analyzing as many as 400 reactions with mass between 15 and 296. Our parametrized formula can reproduced the exact barrier heights and positions within an accur

Ishwar Dutt, Rajeev K. Puri

Using the different versions of phenomenological proximity potential as well as other parametrizations within the proximity concept, we perform a detailed comparative study of fusion barriers for asymmetric colliding nuclei with asymmetry parameter as high as 0.23. In all, 12 different proximity potentials are robust against the experimental data of 60 react

Jing Zhou, Zi Cai, Xu-Bo Zou, Guang-Can Guo

We study the effect of interaction on the temperature change in the process of adiabatic mixing two components of fermi gases by the real-space Bogoliubov-de Gennes (BdG) method. We find that in the process of adiabatic mixing, the competition of the adiabatic expansion and the attractive interaction make it possible to cool or heal the system depending on s

Hongyu He

In this paper, we study the restriction of an irreducible unitary representation $\pi$ of the universal covering $\widetilde{Sp}_{2n}(\mb R)$ to a Heisenberg maximal parabolic group $\tilde P$. We prove that if $\pi|_{\tilde P}$ is irreducible, then $\pi$ must be a highest weight module or a lowest weight module. This is in sharp constrast with the $GL_n(\ma

Zsolt Patakfalvi

We show that the compatibility of the relative canonical sheaf with base change fails generally in families of normal varieties. Furthermore, it always fails if the general fiber of a family of pure dimension n is Cohen-Macaulay and the special fiber contains a strictly S_{n-1} point. In particular, in moduli spaces with functorial relative canonical sheaves

Don Hadwin, Ileana Ionascu, Michael McHugh, Hassan Yousefi

We introduce the notion of C-orbit reflexivity and study its properties. An operator on a finite-dimensional space is C-orbit reflexive if and only if the two largest blocks in its Jordan form corresponding to nonzero eigenvalues with the largest modulus differ in size by at most one. Most of the proofs of our results in infinite dimensions are obtained from

Ping Wu, Wenhua Zhang, Zhenyu Li, Jinlong Yang

By combining first principles transition state location and molecular dynamics simulation, we unambiguously identify a carbon atom approaching induced bridging metal structure formation on Cu (111) surface, which strongly modify the carbon atom coalescence dynamics. The emergence of this new structural motif turns out to be a result of the subtle balance bet

Aleksandrs Slivkins, Filip Radlinski, Sreenivas Gollapudi

Most learning to rank research has assumed that the utility of different documents is independent, which results in learned ranking functions that return redundant results. The few approaches that avoid this have rather unsatisfyingly lacked theoretical foundations, or do not scale. We present a learning-to-rank formulation that optimizes the fraction of sat

Kevin C. Young, Dylan J Gorman, K. Birgitta Whaley

We address the experimentally relevant problem of robust mitigation of dephasing noise acting on a qubit. We first present an extension of a method for representing $1/ω^α$ noise developed by Kuopanportti et al. to the efficient representation of arbitrary Markovian noise. We then add qubit control pulses to enable the design of numerically optimized, two-di

Irina Kostitsyna, Valentin Polishchuk

We prove that it is NP-hard to decide whether two points in a polygonal domain with holes can be connected by a wire. This implies that finding any approximation to the shortest path for a long snake amidst polygonal obstacles is NP-hard. On the positive side, we show that snake&#39;s problem is &#34;length-tractable&#34;: if the snake is &#34;fat&#34;, i.e.

Jiangyuan Li, Athina P. Petropulu, H. Vincent Poor

Cooperative beamforming in relay networks is considered, in which a source transmits to its destination with the help of a set of cooperating nodes. The source first transmits locally. The cooperating nodes that receive the source signal retransmit a weighted version of it in an amplify-and-forward (AF) fashion. Assuming knowledge of the second-order statist

Nicolae Atodiresei, Jens Brede, Predrag Lazic, Vasile Caciuc

By means of ab initio calculations and spin-polarized scanning tunneling microscopy experiments we show how to manipulate the local spin-polarization of a ferromagnetic surface by creating a complex energy dependent magnetic structure. We demonstrate this novel effect by adsorbing organic molecules containing pi(pz)-electrons onto a ferromagnetic surface, in

P. L. Curto-Risso, A. Medina, A. Calvo Hernández, L. Guzmán-Vargas

The cycle-by-cycle variations in heat release for a simulated spark-ignited engine are analyzed within a turbulent combustion model in terms of some basic parameters: the characteristic length of the unburned eddies entrained within the flame front, a characteristic turbulent speed, and the location of the ignition kernel. The evolution of the simulated time

Greg Knese

Every two variable rational inner function on the bidisk has a special representation called a transfer function realization. It is well known and related to important ideas in operator theory that this does not extend to three or more variables on the polydisk. We study the class of rational inner functions on the polydisk which do possess a transfer functi

Tzu-Chieh Wei

Ichikawa et al. [Phys. Rev. A 78, 052105 (2008)] showed that exchange symmetry gives rise to simple characterization of whether multipartite pure quantum states being either globally entangled or fully separable. In this Brief Report, we provide a simple alternative approach and some extension to their conclusions.

Joyce Ann Guzik

Advances in stellar interior modeling are being driven by new data from large-scale surveys and high-precision photometric and spectroscopic observations. Here we focus on single stars in normal evolutionary phases; we will not discuss the many advances in modeling star formation, interacting binaries, supernovae, or neutron stars. We review briefly: 1) upda

Aldo Frezzotti, Gian Pietro Ghiroldi, Livio Gibelli

We show how to accelerate the direct solution of the Boltzmann equation using Graphics Processing Units (GPUs). In order to fully exploit the computational power of the GPU, we choose a method of solution which combines a finite difference discretization of the free-streaming term with a Monte Carlo evaluation of the collision integral. The efficiency of the

Hyoungjeen Jeen, Guneeta Singh-Bhalla, Patrick R. Mickel, Kristen Voigt

We have grown epitaxial thin films of multiferroic BiMnO$_3$ using pulsed laser deposition. The films were grown on SrTiO$_3$ (001) substrates by ablating a Bi-rich target. Using x-ray diffraction we confirmed that the films were epitaxial and the stoichiometry of the films was confirmed using Auger electron spectroscopy. The films have a ferromagnetic Curie

Xi Dong, Bart Horn, Eva Silverstein, Gonzalo Torroba

We develop tools to engineer de Sitter vacua with semi-holographic duals, using elliptic fibrations and orientifolds to uplift Freund-Rubin compactifications with CFT duals. The dual brane construction is compact and constitutes a microscopic realization of the dS/dS correspondence, realizing d-dimensional de Sitter space as a warped compactification down to

Luca Bertello, Roger K. Ulrich, John E. Boyden

It is well established that both total and spectral solar irradiance are modulated by variable magnetic activity on the solar surface. However, there is still disagreement about the contribution of individual solar features for changes in the solar output, in particular over decadal time scales. Ionized Ca II K line spectroheliograms are one of the major res

Catherine Williams

We construct an example of a spherically symmetric black hole interior in which there is NO (spherically symmetric) marginally trapped tube asymptotic to the event horizon. The construction uses a self-gravitating massive scalar field matter model, and the key condition we impose is that the scalar field $ϕ$ be bounded below by a positive constant along the

Francisco Javier Gallego, Miguel González, Bangere P. Purnaprajna

The purpose of this article is to study the deformations of smooth surfaces $X$ of general type whose canonical map is a finite, degree 2 morphism onto a minimal rational surface or onto $\mathbf F_1$, embedded in projective space by a very ample complete linear series. Among other things, we prove that any deformation of the canonical morphism of such surfa

F. L. Vieyro, G. E. Romero, G. S. Vila

Cygnus X-1 was the first X-ray source widely accepted to be a black hole candidate and remains among the most studied astronomical objects in its class. The detection of non-thermal radio, hard X-rays and gamma rays reveals the fact that this kind of objects are capable of accelerating particles up to very high energies. In order to explain the electromagnet

Valerio Faraoni

Due to the failure of Birkhoff&#39;s theorem, black holes in f(R) gravity theories in which an effective time-varying cosmological &#34;constant&#34; is present are, in general, dynamical. Clifton&#39;s exact spherical solution of R^(1+δ) gravity, which is dynamical and describes a central object embedded in a spatially flat universe, is studied. It is shown

Stefano Meschiari, Gregory Laughlin

Transit timing variations - deviations from strict periodicity between successive passages of a transiting planet - can be used to probe the structure and dynamics of multiple-planet systems. In this paper, we examine prospects for numerically solving the so-called inverse problem, the determination of the orbital elements of a perturbing body from the trans

R. Barends, N. Vercruyssen, A. Endo, P. J. de Visser

We report a reduction of the frequency noise in coplanar waveguide superconducting resonators. The reduction of 7 dB is achieved by removing the exposed dielectric substrate surface from the region with high electric fields and by using NbTiN. In a model-analysis the surface of NbTiN is found to be a negligible source of noise, experimentally supported by a

Neil D. Christensen, Tao Han, Yingchuan Li

We study genuine CP-odd observables at the LHC to test the CP property of the ZZH interaction for a Higgs boson with mass below the threshold to a pair of gauge bosons via the process p,p -> Z,H -> l+,l-,b,bbar. We illustrate the analysis by including a CP-odd ZZH coupling, and show how to extract the CP asymmetries in the signal events. After selective kine

David R. Law, Steven R. Majewski

Numerical models of the tidal disruption of the Sagittarius (Sgr) dwarf galaxy have recently been developed that for the first time simultaneously satisfy most observational constraints on the angular position, distance, and radial velocity trends of both leading and trailing tidal streams emanating from the dwarf. We use these dynamical models in combinatio

Jorge Penarrubia, Sergey E. Koposov, Matthew G. Walker, Gerry Gilmore

We use analytical and N-body methods to examine the survival of wide stellar binaries against repeated encounters with dark substructures orbiting in the dark matter haloes of dwarf spheroidal galaxies (dSphs). Our models adopt cosmologically-motivated conditions wherein dSphs are dark-matter dominated systems that form hierarchically and orbit about a host

Takeshi Isobe, Antonella Marini

In this paper we complete the proof of the existence of multiple solutions (and, in particular, non minimal ones), to the epsilon-Dirichlet problem obtained as a variational problem for the SU(2)-epsilon-Yang Mills functional. This is equivalent to proving the existence of multiple solutions to the Dirichlet problem for the SU(2)-Yang Mills functional with s

M. Garny, A. Hohenegger, A. Kartavtsev

Using the closed-time-path formalism we quantify gradient corrections to the kinetic equations for leptogenesis, that are neglected in the standard Boltzmann approach. In particular we show that an additional CP-violating source term arises, which is non-zero even when all species are in local thermal equilibrium. In the early universe it is proportional to

Evghenii Gaburov, Jeroen Bédorf, Simon Portegies Zwart

We present a new very fast tree-code which runs on massively parallel Graphical Processing Units (GPU) with NVIDIA CUDA architecture. The tree-construction and calculation of multipole moments is carried out on the host CPU, while the force calculation which consists of tree walks and evaluation of interaction list is carried out on the GPU. In this way we a

Adrian Del Maestro, Ian Affleck

Harmonically trapped ultra-cold atoms and helium-4 in nanopores provide new experimental realizations of bosons in one dimension, motivating the search for a more complete theoretical understanding of their low energy properties. Worm algorithm path integral quantum Monte Carlo results for interacting bosons restricted to the one dimensional continuum are co

Rajendra R. Zope, Tunna Baruah, Mark R. Pederson, Steven L. Richardson

The recent synthesis of a four-fold silylated sila-adamantane molecule (C$_{24}$H$_{72}$Si$_{14}$, T$_d$), [J. Fischer, J. Baumgartner, and C. Marschner, {\it Science} {\bf 310,} (2005) 825] is the first attempt of making the silicon analogue of adamantane. It has adamantane-like Si$_{10}$ core, capped by methyl and sily-methyl ligands. We report its electro

Jinfeng Liao, Volker Koch, Adam Bzdak

In this paper, we discuss alternative means of measuring the possible presence of local parity violation in relativistic heavy ion collisions. We focus on the phenomenon of charge separation and introduce the charged dipole vector $\hat{Q}^c_1$, which will measure the charge separation on an event-by-event basis. Using Monte Carlo events, we demonstrate the

Takeshi Isobe, Antonella Marini

In this paper (Part I) and its sequels (Part II and Part III), we analyze the structure of the space of solutions to the epsilon-Dirichlet problem for the Yang-Mills equations on the 4-dimensional disk, for small values of the coupling constant epsilon. These are in one-to-one correspondence with solutions to the Dirichlet problem for the Yang Mills equation

Jeremy Shears, Robert Koff, Richard Sabo, Bart Staels

We report unfiltered photometry during the first confirmed superoutburst of the recently discovered dwarf nova, SDSS J073208.11+413008.7 and conclude that it is a member of the SU UMa family. At its brightest, the star was magnitude 15.7. The outburst amplitude was nearly 5 magnitudes and it lasted about 14 days. We determined the mean superhump period from

CLEO Collaboration, P. U. E. Onyisi, J. L. Rosner, J. P. Alexander

Using a sample of 25.9 million psi(2S) decays acquired with the CLEO-c detector at the CESR e^+e^- collider, we report branching fractions for the decays chi_cJ -> p p-bar pi^0, p p-bar eta, and p p-bar omega, with J=0,1,2. Our results for B(chi_cJ-> p p-bar pi^0) and B(chi_cJ-> p p-bar eta) are consistent with, but more precise than, previous measurements.

Mark W. Keller, M. R. Pufall, W. H. Rippard, T. J. Silva

We measure the power spectral density of frequency fluctuations in nanocontact spin torque oscillators over time scales up to 50 ms. We use a mixer to convert oscillator signals ranging from 10 GHz to 40 GHz into a band near 70 MHz before digitizing the time domain waveform. We analyze the waveform using both zero crossing time stamps and a sliding Fourier t

Denis Gryaznov, Eugene Heifets, David Sedmidubsky

We have performed a detailed analysis of the magnetic (collinear and noncollinear) order and atomic and the electron structures of UO2, PuO2 and UN on the basis of density functional theory with the Hubbard electron correlation correction (DFT+U). We have shown that the 3-k magnetic structure of UO2 is the lowest in energy for the Hubbard parameter value of

Wai-Leong Yeow, Cédric Westphal, Ulaş C. Kozat

In a virtualized infrastructure where physical resources are shared, a single physical server failure will terminate several virtual servers and crippling the virtual infrastructures which contained those virtual servers. In the worst case, more failures may cascade from overloading the remaining servers. To guarantee some level of reliability, each virtual

Chris Shrader, Lev Titarchuk, Nikolai Shaposhnikov

The bright and highly variable X-ray and radio source known as Cygnus X-3 was among the first X-ray sources discovered, yet it remains in many ways an enigma. Its known to consist of a massive, Wolf-Rayet primary in an extremely tight orbit with a compact object. Yet one of the most basic of parameters - the mass of the compact object - is not known. Nor is

Hailong Dao, Craig Huneke

Let R be a Cohen-Macaulay ring and M a maximal Cohen-Macaulay R-module. Inspired by recent striking work by Iyama, Burban-Iyama-Keller-Reiten and Van den Bergh we study the question of when the endomorphism ring of M has finite global dimension via certain conditions about vanishing of $\Ext$ modules. We are able to strengthen certain results by Iyama on con

J. Atulasimha, S. Bandyopadhyay

The authors show that it is possible to rotate the magnetization of a multiferroic (strain-coupled two-layer magnetostrictive-piezoelectric) nanomagnet by a large angle with a small electrostatic potential. This can implement Bennett clocking in nanomagnetic logic arrays resulting in unidirectional propagation of logic bits from one stage to another. This me

Andy Buckley, Hendrik Hoeth, Heiko Lacker, Holger Schulz

Data analyses in hadron collider physics depend on background simulations performed by Monte Carlo (MC) event generators. However, calculational limitations and non-perturbative effects require approximate models with adjustable parameters. In fact, we need to simultaneously tune many phenomenological parameters in a high-dimensional parameter-space in order

H. Nemura, for HAL QCD, PACS-CS Collaboration

We present our latest study of Lambda-Nucleon (LN) interaction by using lattice QCD, following up on our report at LATTICE 2008. We have calculated not only the scattering lengths but also the central and tensor potentials, which are obtained from the Bethe-Salpeter (BS) amplitude measured in lattice QCD. For these calculations, we employ two different types

P. R. Fraser, K. Amos, L. Canton, S. Karataglidis

The physics of radioactive ion beams implies the description of weakly-bound nuclear systems. One key aspect concerns the coupling to low-lying collective-type excited states, which for these systems might not be stable levels, but particle emitting resonances. In this work we describe how the scattering cross section and compound spectra change when the col

C. Wang, P. G. Kevrekidis, D. J. Frantzeskakis, B. A. Malomed

We consider the interplay of linear double-well-potential (DWP) structures and nonlinear longrange interactions of different types, motivated by applications to nonlinear optics and matter waves. We find that, while the basic spontaneous-symmetry-breaking (SSB) bifurcation structure in the DWP persists in the presence of the long-range interactions, the crit

J. V. Bennett, M. Kornicer, M. R. Shepherd, M. M. Ito

We present the timing characteristics of the flash ADC readout of the GlueX forward calorimeter, which depends on precise measurement of arrival time of pulses from FEU 84-3 photomultiplier tubes to suppress backgrounds. The tests presented were performed using two different 250 MHz prototype flash ADC devices, one with eight-bit and one with twelve-bit samp

Ming Lei, Pierre Del Moral, Christophe Baehr

In practical nonlinear filtering, the assessment of achievable filtering performance is important. In this paper, we focus on the problem of efficiently approximate the posterior Cramer-Rao lower bound (CRLB) in a recursive manner. By using Gaussian assumptions, two types of approximations for calculating the CRLB are proposed: An exact model using the state

Samir Kumar Bhowmik

We consider a linear partial integro-differential equation that arises in the modeling of various physical and biological processes. We study the problem in a spatial periodic domain. We analyze numerical stability and numerical convergence of a one step approximation of the problem with smooth and non-smooth initial functions.

Livio Flaminio, Miguel Paternain

We study the cohomological equation for a smooth vector field on a compact manifold. We show that if the vector field is cohomology free, then it can be embedded continuously in a linear flow on an Abelian group.

Peter Koval, Dietrich Foerster, Olivier Coulaud

We describe a fast parallel iterative method for computing molecular absorption spectra within TDDFT linear response and using the LCAO method. We use a local basis of &#34;dominant products&#34; to parametrize the space of orbital products that occur in the LCAO approach. In this basis, the dynamical polarizability is computed iteratively within an appropri

Kausik Majumdar, Navakanta Bhat, Prashant Majhi, Raj Jammy

In this paper, we focus on the performance of a nanowire Field Effect Transistor (FET) in the Ultimate Quantum Capacitance Limit (UQCL) (where only one subband is occupied) in the presence of interface traps ($D_{it}$), parasitic capacitance ($C_L$) and source/drain series resistance ($R_{s,d}$) using a ballistic transport model and compare the performance w

Marten F. Byl, James T. Demers, Edward A. Rietman

Rapid identification of object from radar cross section (RCS) signals is important for many space and military applications. This identification is a problem in pattern recognition which either neural networks or support vector machines should prove to be high-speed. Bayesian networks would also provide value but require significant preprocessing of the sign

Christian Wyss

An algebraic Riccati equation for linear operators is studied, which arises in systems theory. For the case that all involved operators are unbounded, the existence of infinitely many selfadjoint solutions is shown. To this end, invariant graph subspaces of the associated Hamiltonian operator matrix are constructed by means of a Riesz basis with parentheses

Piyali Chatterjee, Gustavo Guerrero, Axel Brandenburg

Dynamos in the Sun and other bodies tend to produce magnetic fields that possess magnetic helicity of opposite sign at large and small scales, respectively. The build-up of magnetic helicity at small scales provides an important saturation mechanism. In order to understand the nature of the solar dynamo we need to understand the details of the saturation mec

Martin Chuaqui, Peter Duren, Brad Osgood

In earlier work the authors have extended Nehari&#39;s well-known Schwarzian derivative criterion for univalence of analytic functions to a univalence criterion for canonical lifts of harmonic mappings to minimal surfaces. The present paper develops some quantitative versions of that result in the form of two-point distortion theorems. Along the way some dis

The CMS Collaboration

We present a measurement of the ratio of positive to negative muon fluxes from cosmic ray interactions in the atmosphere, using data collected by the CMS detector both at ground level and in the underground experimental cavern at the CERN LHC. Muons were detected in the momentum range from 5 GeV/c to 1 TeV/c. The surface flux ratio is measured to be 1.2766 \

G. L. Pilbratt, J. R. Riedinger, T. Passvogel, G. Crone

Herschel was launched on 14 May 2009, and is now an operational ESA space observatory offering unprecedented observational capabilities in the far-infrared and submillimetre spectral range 55-671 μm. Herschel carries a 3.5 metre diameter passively cooled Cassegrain telescope, which is the largest of its kind and utilises a novel silicon carbide technology. T

Claude Bardos, David Lannes

We present here a survey of recent results concerning the mathematical analysis of instabilities of the interface between two incompressible, non viscous, fluids of constant density and vorticity concentrated on the interface. This configuration includes the so-called Kelvin-Helmholtz (the two densities are equal), Rayleigh-Taylor (two different, nonzero, de

Adrien Lerbret, Frederic Affouard, Patrice Bordat, Alain Hedoux

The dynamics of water in aqueous solutions of three homologous disaccharides, namely trehalose, maltose and sucrose, has been analyzed by means of molecular dynamics simulations in the 0-66 wt % concentration range. The low-frequency vibrational densities of states (VDOS) of water were compared with the susceptibilities chi&#34; of 0-40 wt % solutions of tre

Sanjeev Kumar, Suneel Kumar

Using the isospin-dependent quantum molecular dynamical (IQMD) model, we systematically study the role of momentum dependent interactions in global stopping and analyze the effect of symmetry energy in the presence of momentum dependent interactions. For this, we simulate the reactions by varying the total mass of the system from 80 to 394 at different beam

E. Winston, S. T. Megeath, S. Wolk, B. Spitzbart

We present Chandra X-ray data of the NGC 1333 embedded cluster, combining these data with existing Chandra data, Sptizer photometry and ground based spectroscopy of both the NGC 1333 & Serpens North clusters to perform a detailed study of the X-ray properties of two of the nearest embedded clusters to the Sun. In NGC 1333, a total of 95 cluster members are d

Jibitesh Dutta, Subenoy Chakraborty, M. Ansari

In this paper, we investigate the validity of the generalized second law of thermodynamics of the universe in the DGP brane world.The boundary of the universe is assumed to be enclosed by the dynamical apparent horizon or the event horizon. The universe is chosen to be homogeneous and isotropic and the validity of the first law has been assumed here. The mat

Sanjeev Kumar, Suneel Kumar

We aim to understand the role of NN cross-sections, equation of state as well as different model ingredients such as width of Gaussian, clusterisation range and different clusterisation algorithms in multifragmentation using quantum molecular dynamics model. We notice that all model ingredients have sizable effect on the fragment pattern.