August 2008 arXiv papers — page 8

J. Bland-Hawthorn, J. S. Gallagher

We provide a brief overview of some key issues that came out of the IAU 256 symposium on the Magellanic System (http://www.astro.keele.ac.uk/iaus256)

Tobias Westmeier, Christian Brüns, Jürgen Kerp

Using the 100-m radio telescope at Effelsberg, we mapped a large area around the Andromeda Galaxy in the 21-cm line emission of neutral hydrogen to search for high-velocity clouds (HVCs) out to large projected distances in excess of 100 kpc. Our 3-sigma HI mass sensitivity for the warm neutral medium is 8x10^4 solar masses. We can confirm the existence of a

A. Parravano, L. M. Reyes

We propose a model to represent the motility of social elements. The model is completely deterministic, possesses a small number of parameters, and exhibits a series of properties that are reminiscent of the behavior of comunities in social-ecological competition; these are: (i) similar individuals attract each other; (ii) individuals can form stable groups;

Haruka Tanji, Saikat Ghosh, Jonathan Simon, Benjamin Bloom

We demonstrate a heralded quantum memory based on mapping of a photon polarization state onto a single collective-spin excitation (magnon) shared between two spatially overlapped atomic ensembles. The polarization fidelity is measured by quantum state tomography to be above 90(2)% for any input polarization, which far exceeds the classical limit of 2/3. The

Geert Verbeke, Geert Molenberghs, Caroline Beunckens

Model selection and assessment with incomplete data pose challenges in addition to the ones encountered with complete data. There are two main reasons for this. First, many models describe characteristics of the complete data, in spite of the fact that only an incomplete subset is observed. Direct comparison between model and data is then less than straightf

H. L. Maness, M. P. Fitzgerald, R. Paladini, P. Kalas

We present the first detection and mapping of the HD 32297 debris disk at 1.3 mm with the Combined Array for Research in Millimeter-wave Astronomy (CARMA). With a sub-arcsecond beam, this detection represents the highest angular resolution (sub)mm debris disk observation made to date. Our model fits to the spectral energy distribution from the CARMA flux and

I. Daubechies, M. Fornasier, I. Loris

Regularization of ill-posed linear inverse problems via $\ell_1$ penalization has been proposed for cases where the solution is known to be (almost) sparse. One way to obtain the minimizer of such an $\ell_1$ penalized functional is via an iterative soft-thresholding algorithm. We propose an alternative implementation to $\ell_1$-constraints, using a gradien

Christopher Savage, Graciela Gelmini, Paolo Gondolo, Katherine Freese

The DAMA/NaI and DAMA/LIBRA annual modulation data, which may be interpreted as a signal for the existence of weakly interacting dark matter (WIMPs) in our galactic halo, are examined in light of null results from other experiments. We use the energy spectrum of the combined DAMA modulation data given in 36 bins, and include the effect of channeling. Several

Nicola Ferralis, Roya Maboudian, Carlo Carraro

The early stages of epitaxial graphene layer growth on the Si-terminated 6H-SiC(0001) are investigated by Auger electron spectroscopy (AES) and depolarized Raman spectroscopy. The selection of the depolarized component of the scattered light results in a significant increase in the C-C bond signal over the second order SiC Raman signal, which allows to resol

G. N. Mace, L. Prato, L. H. Wasserman, G. H. Schaefer

The young system RX J0529.3+1210 was initially identified as a single-lined spectroscopic binary. Using high-resolution infrared spectra, acquired with NIRSPEC on Keck II, we measured radial velocities for the secondary. The method of using the infrared regime to convert single-lined spectra into double-lined spectra, and derive the mass ratio for the binary

Samuel Lundqvist

We discuss four different constructions of vector space bases associated to vanishing ideals of points. We show how to compute normal forms with respect to these bases and give new complexity bounds. As an application, we improve the computational algebra approach to the reverse engineering of gene regulatory networks.

Annalisa Calini, Thomas Ivey, Gloria Mari Beffa

We study the relation between the centro-affine geometry of star-shaped planar curves and the projective geometry of parametrized maps into $\RP^1$. We show that projectivization induces a map between differential invariants and a bi-Poisson map between Hamiltonian structures. We also show that a Hamiltonian evolution equation for closed star-shaped planar c

T. V. Tscherbul, Yu. V. Suleimanov, V. Aquilanti, R. V. Krems

We present an accurate quantum mechanical study of molecule-molecule collisions in the presence of a magnetic field. The work focusses on the analysis of elastic scattering and spin relaxation in collisions of O2(3Sigma_g) molecules at cold (~0.1 K) and ultracold (~10^{-6} K) temperatures. Our calculations show that magnetic spin relaxation in molecule-molec

Yang Chen, Alexander Its

In this paper, we study a certain linear statistics of the unitary Laguerre ensembles, motivated in part by an integrable quantum field theory at finite temperature. It transpires that this is equivalent to the characterization of a sequence of polynomials orthogonal with respect to the weight $$ w(x)=w(x,s):=x^{\al}\rme^{-x}\rme^{-s/x}, \quad 0\leq x<\infty

Marcos Craizer, Henri Anciaux, Thomas Lewiner

In this paper we are interested in defining affine structures on discrete quadrangular surfaces of the affine three-space. We introduce, in a constructive way, two classes of such surfaces, called respectively indefinite and definite surfaces. The underlying meshes for indefinite surfaces are asymptotic nets satisfying a non-degeneracy condition, while the u

The BABAR Collaboration, B. Aubert

We perform a time-dependent and time-integrated angular analysis of the decays $B^0\toϕK^{*}(892)^0$, $ϕK^{*}_2(1430)^0$, and $ϕ(Kπ)^{*0}_{0}$ with the final sample of about 465 million $\BB$ pairs recorded with the $\babar$ detector. Twenty-four parameters are investigated, including the branching fractions, CP-violation parameters, and parameters sensitive

Walter Winter

Non-standard physics which can be described by effective four fermion interactions may be an additional source of CP violation in the neutrino propagation. We discuss the detectability of such a CP violation at a neutrino factory. We assume the current baseline setup of the international design study of a neutrino factory (IDS-NF) for the simulation. We find

M. M. Miller Bertolami, L. G. Althaus, K. Unglaub, A. Weiss

We present 1D numerical simulations aimed at studying the hot-flasher scenario for the formation of He-rich subdwarf stars. Sequences were calculated for a wide range of metallicities and physical assumptions, such as the stellar mass at the moment of the helium core flash. This allows us to study the two previously proposed flavors of the hot-flasher scenar

Michael Kunzinger, Roman O. Popovych

The notion of singular reduction operators, i.e., of singular operators of nonclassical (conditional) symmetry, of partial differential equations in two independent variables is introduced. All possible reductions of these equations to first-order ODEs are are exhaustively described. As examples, properties of singular reduction operators of (1+1)-dimensiona

Richard G. Baraniuk, Volkan Cevher, Marco F. Duarte, Chinmay Hegde

Compressive sensing (CS) is an alternative to Shannon/Nyquist sampling for the acquisition of sparse or compressible signals that can be well approximated by just K << N elements from an N-dimensional basis. Instead of taking periodic samples, CS measures inner products with M < N random vectors and then recovers the signal via a sparsity-seeking optimizatio

D. Eriksson, F. Mahmoudi, O. Stål

We discuss the phenomenology of charged Higgs bosons in the MSSM with minimal flavor violation. In addition to the constrained MSSM (CMSSM) with universal soft supersymmetry breaking mass parameters at the GUT scale, we explore non-universal Higgs mass models (NUHM) where this universality condition is relaxed. To identify the allowed parameter space regions

Itiel Dror, Stevan Harnad

&#34;Cognizing&#34; (e.g., thinking, understanding, and knowing) is a mental state. Systems without mental states, such as cognitive technology, can sometimes contribute to human cognition, but that does not make them cognizers. Cognizers can offload some of their cognitive functions onto cognitive technology, thereby extending their performance capacity bey

Benoît Avez, Cédric Simenel, Philippe Chomaz

We study pairing vibrations in $^{18,20,22}$O and $^{42,44,46}$Ca nuclei solving the time-dependent Hartree-Fock-Bogoliubov equation in coordinate space with spherical symmetry. We use the SLy4 Skyrme functional in the normal part of the energy density functional and a local density dependent functional in its pairing part. Pairing vibrations are excited by

Igor A. Bandos

We develop the N=8 superfield description of the Bagger-Lambert-Gustavsson (BLG) model in its Nambu bracket (NB) realization. The basic ingredient is the octet of scalar d=3 N=8 superfields depending also on the coordinates of a compact three dimensional space M. It is restricted by the &#39;superembedding-like&#39; equation, which can be treated as covarian

V. V. Zhuravlev, N. I. Shakura

The dynamics of small global perturbations in the form of linear combination of a finite number of non-axisymmetric eigenmodes is studied in two-dimensional approximation. The background flow is assumed to be an axisymmetric perfect fluid with the adiabatic index $γ=5/3$ rotating with power law angular velocity distribution $Ω\propto r^{-q}$, $1.5<q<2.0$, co

Travis Norsen, Joshua Lande, S. B. McKagan

We discuss &#34;the plane wave approximation&#34; to quantum mechanical scattering using simple one-dimensional examples. The central points of the paper are that (a) plane waves should be thought of as infinitely wide wave packets, and (b) the calculations of reflection and transmission probabilities $R$ and $T$ in standard textbook presentations involve an

Curtis Struck, Daniel C. Smith

The existence of partially ionized, diffuse gas and dust clouds at kiloparsec scale distances above the central planes of edge-on, galaxy discs was an unexpected discovery about 20 yrs ago. Subsequent observations showed that this EDIG (extended or extraplanar diffuse interstellar gas) has rotation velocities approximately 10-20% lower than those in the cent

Jonathan Loranger, Kayll Lake

We generate an explicit four-fold infinity of physically acceptable exact perfect fluid solutions of Einstein&#39;s equations by way of conformal transformations of physically unacceptable solutions (one way to view the use of isotropic coordinates). Special cases include the Schwarzschild interior solution and the Einstein static universe. The process we co

T. M. Wright, R. J. Ballagh, A. S. Bradley, P. B. Blakie

We present a quantum mechanical treatment of the mechanical stirring of Bose-Einstein condensates using classical field techniques. In our approach the condensate and excited modes are described using a Hamiltonian classical field method in which the atom number and (rotating frame) energy are strictly conserved. We simulate a T = 0 quasi-2D condensate pertu

Ioan Raicu, Zhao Zhang, Mike Wilde, Ian Foster

We have extended the Falkon lightweight task execution framework to make loosely coupled programming on petascale systems a practical and useful programming model. This work studies and measures the performance factors involved in applying this approach to enable the use of petascale systems by a broader user community, and with greater ease. Our work enable

Karel Van Acoleyen

Lemaitre-Tolman-Bondi (LTB) solutions are used frequently to describe the collapse or expansion of spherically symmetric inhomogeneous mass distributions in the Universe. These exact solutions are obtained in the synchronous gauge where nonlinear dynamics (with respect to the FLRW background) induce large deviations from the FLRW metric. In this paper we sho

Joel Merker

A major unsolved problem (according to Demailly 1997) towards the Kobayashi hyperbolicity conjecture in optimal degree is to understand jet differentials of germs of holomorphic discs that are invariant under any reparametrization of the source. The underlying group action is not reductive, but we provide a complete algorithm to generate all invariants, in a

Dusa McDuff

In an earlier paper we explained how to convert the problem of symplectically embedding one 4-dimensional ellipsoid into another into the problem of embedding a certain set of disjoint balls into \CP^2 by using a new way to desingularize orbifold blow ups Z of the weighted projective space \CP^2_{1,m,n}. We now use a related method to construct symplectomorp

Shaofang Hong, Jianrong Zhao, Wei Zhao

Let $p$ be a prime. In this paper, we present a detailed $p$-adic analysis to factorials and double factorials and their congruences. We give good bounds for the $p$-adic sizes of the coefficients of the divided universal Bernoulli number ${{\hat B_n}\over n}$ when $n$ is divisible by $p-1$. Using these we then establish the universal Kummer congruences modu

Qing-feng Zhan, Stijn Vandezande, Kristiaan Temst, Chris Van Haesendonck

We investigate the magnetization reversal in Fe/MgO(001) films with fourfold in-plane magnetic anisotropy and an additional uniaxial anisotropy whose orientation and strength are tuned using different growth geometries and post growth treatments. The previously adopted mechanism of 180^{o} domain wall nucleation clearly fails to explain the observed 180^{o}

Christopher J. Leininger, Mahan Mj, Saul Schleimer

In genus two and higher, the fundamental group of a closed surface acts naturally on the curve complex of the surface with one puncture. Combining ideas from previous work of Kent--Leininger--Schleimer and Mitra, we construct a universal Cannon--Thurston map from a subset of the circle at infinity for the closed surface group onto the boundary of the curve c

Cédric Bonnafé

Computations in small Coxeter groups or dihedral groups suggest that the partition into Kazhdan-Lusztig cells with unequal parameters should obey to some semicontinuity phenomenon (as the parameters vary). The aim of this paper is to provide a rigorous theoretical background for supporting this intuition that will allow to state several precise conjectures.

Eugene V. Sukhorukov, Andrew N. Jordan

We demonstrate that by utilizing an over-screened Josephson junction as a noise detector it is possible to achieve the threshold regime, whereby the tails of the fluctuating current distribution are measured. This situation is realized by placing the Josephson junction and mesoscopic conductor in an external circuit with very low impedance. In the underdampe

E. Molinaro, S. T. Petcov

The CP-violation necessary for the generation of the baryon asymmetry of the Universe $Y_B$ in the &#34;flavoured&#34; leptogenesis scenario can arise from the &#34;low energy&#34; PMNS neutrino mixing matrix $U$ and/or from the &#34;high energy&#34; part of neutrino Yukawa couplings, which can mediate CP-violating phenomena only at some high energy scale. T

David Ridout

The logarithmic conformal field theory describing critical percolation is further explored using Watts&#39; determination of the probability that there exists a cluster connecting both horizontal and vertical edges. The boundary condition changing operator which governs Watts&#39; computation is identified with a primary field which does not fit naturally wi

V. Jayanth, C. Raghunandan, Anindya Kumar Biswas

A small sphere placed on the top of a big static frictionless sphere, slips until it leaves the surface at an angle $θ_{l}=\cos^{-1}{2/3}$. On the other extreme, if the surface of the big sphere has coefficient of static friction, $μ_s\to\infty$, the small sphere starts rolling and continues to do so until it leaves the surface at an angle $θ_{l} =\cos^{-1}{

Faycal Ben Adda

The incorporation of an adequate discrete expansion to the formalism of the special relativity that does not allow gravitational acceleration unravels unexplored phenomena. This extension takes into account consequences of a small variation of the limiting velocity for a large scale of time together with the space-time expansion. It determines a natural boun

The BABAR Collaboration, B. Aubert

We present a study of the charmless semileptonic B-meson decays B+ -> omega l+ nu and B+ -> eta l+ nu. The analysis is based on 383 million BBbar pairs recorded at the Upsilon(4S) resonance with the BABAR detector. The omega mesons are reconstructed in the channel omega -> pi+ pi- pi0 and the eta mesons in the channels eta -> pi+ pi- pi0 and eta -> gamma gam

Christian Kremers, Dmitry N. Chigrin, Johann Kroha

The Cherenkov radiation is substantially modified in the presence of a medium with a nontrivial dispersion relation. We consider Cherenkov emission spectra of a point charge moving in general three- (3D) and two-dimensional (2D) photonic crystals. Exact analytical expressions for the spectral distribution of the radiated power are obtained in terms of the Bl

Yunkyu Bang, Han-Yong Choi, Hyekyung Won

We study the impurity suppression of the critical temperature $T_c$ of the FeAs superconductors theoretically based on the the $\pm$s-wave pairing state of a two band model. The effects of non-magnetic and magnetic impurities are studied with the $\mathcal{T}$-matrix approximation, which can continuously treat impurity scattering from weak to strong coupling

Tibor Antal, P. L. Krapivsky, A. Rákos

We study zero-temperature quantum spin chains which are characterized by a non-vanishing current. For the XX model starting from the initial state |... + + + - - - ...> we derive an exact expression for the variance of the total spin current. We show that asymptotically the variance exhibits an anomalously slow logarithmic growth; we also extract the sub-lea

F. Igloi, L. Turban

We consider the Ising model on the Bethe lattice with aperiodic modulation of the couplings, which has been studied numerically in Phys. Rev. E 77, 041113 (2008). Here we present a relevance-irrelevance criterion and solve the critical behavior exactly for marginal aperiodic sequences. We present analytical formulae for the continuously varying critical expo

K. I. Caputi, K. Kovac, M. Bolzonella, S. J. Lilly

We investigate the close environment of 203 Spitzer 24 micron-selected sources at 0.6<z<1.0 using zCOSMOS-bright redshifts and spectra of I<22.5 AB mag galaxies, over 1.5 sq. deg. of the COSMOS field. We quantify the degree of passivity of the LIRG and ULIRG environments by analysing the fraction of close neighbours with Dn(4000)>1.4. We find that LIRGs at 0

Frank Simon, James Kelsey, Michael Kohl, Richard Majka

Three Gas-Electron-Multiplier tracking detectors with an active area of 10 cm x 10 cm and a two-dimensional, laser-etched orthogonal strip readout have been tested extensively in particle beams at the Meson Test Beam Facility at Fermilab. These detectors used GEM foils produced by Tech-Etch, Inc. They showed an efficiency in excess of 95% and spatial resolut

P. S. Sastry, K. P. Unnikrishnan

In this paper we consider the problem of detecting statistically significant sequential patterns in multi-neuronal spike trains. These patterns are characterized by ordered sequences of spikes from different neurons with specific delays between spikes. We have previously proposed a data mining scheme to efficiently discover such patterns which are frequent i

Carlo Rovelli

I study the physical meaning of Deformed, or Doubly, Special Relativity (DSR). I argue that DSR could be physically relevant in a certain large-distance limit. I consider a concrete physical effect: the gravitational slowing down of time due to the gravitational potential well of a massive-particle, and its effect on the dynamics of the particle itself. I ar

Takuya Kanazawa

We extend the inequality of Tomboulis and Yaffe in SU(2) lattice gauge theory (LGT) to SU(N) LGT and to general classical spin systems, by use of reflection positivity. Basically the inequalities guarantee that a system in a box that is sufficiently insensitive to boundary conditions has a non-zero mass gap. We explicitly illustrate the theorem in some solva

Dirk Zerwas

The extraction of the parameters of the supersymmetric Lagrangian is discusse d. Particular emphasis is put on the rigorous treatment of experimental and theo retical errors. While the LHC can provide a valuable first estimate of the parameters, the combination of LHC and ILC will be nece ssary to determine with high precision the parameters of the MSSM.

Georg Böcherer, Alexandre de Baynast

Cooperative communications have emerged as a significant concept to improve reliability and throughput in wireless systems. On the other hand, WLANs based on random access mechanism have become popular due to ease of deployment and low cost. Since cooperation introduces extra transmissions among the cooperating nodes and therefore increases the number of pac

Hiroya Yamaguchi, Aya Bamba, Katsuji Koyama

This paper reports on the Suzaku results of thermal and non-thermal features of 30 Dor C, a supernova remnant (SNR) in a superbubble of the Large Magellanic Cloud (LMC). The west rim exhibits a non-thermal X-ray spectrum with no thermal component. A single power-law model is rejected but a power-law model with spectral cutoff is accepted. The cutoff frequenc

T. Numata, Y. Nisikawa, A. Oguri, A. C. Hewson

We study the conductance through a triangular triple quantum dot, which are connected to two noninteracting leads, using the numerical renormalization group (NRG). It is found that the system shows a variety of Kondo effects depending on the filling of the triangle. The SU(4) Kondo effect occurs at half-filling, and a sharp conductance dip due to a phase lap

Maria Vlasiou, Zbigniew Palmowski

We investigate the tail behaviour of the steady state distribution of a stochastic recursion that generalises Lindley&#39;s recursion. This recursion arises in queuing systems with dependent interarrival and service times, and includes alternating service systems and carousel storage systems as special cases. We obtain precise tail asymptotics in three quali

So Matsuura

We consider the Hanany-Witten type brane configuration in a background of RR 4-form field strength and examine the behavior of Euclidean D0-branes propagating between two NS5-branes. We evaluate the partition function of the D0-branes and show that it coincides with the Nekrasov partition function of instantons for four-dimensional N=2 supersymmetric Yang-Mi

Hosub Jin, Hogyun Jeong, Taisuke Ozaki, Jaejun Yu

We present a microscopic model for the anisotropic exchange interactions in Sr$_{2}$IrO$_{4}$. A direct construction of Wannier functions from first-principles calculations proves the $j_{\mathrm{eff}}$=1/2 character of the spin-orbit integrated states at the Fermi level. An effective $j_{\mathrm{eff}}$-spin Hamiltonian explains the observed weak ferromagnet

L. Neslusan

During the last stage of collapse of a compact object into the horizon of events, the potential energy of its surface layer decreases to a negative value below all limits. The energy-conservation law requires an appearance of a positive-valued energy to balance the decrease. We derive the internal-state properties of the ideal gas situated in an extremely st

Songbai Chen, Bin Wang, Jiliang Jing

We investigate the background dynamics when dark energy is coupled to dark matter in the universe described by Einstein cosmology and Loop Quantum Cosmology. We introduce a new general form of dark sector coupling, which presents us a more complicated dynamical phase space. Differences in the phase space in obtaining the accelerated scaling attractor in Eins

Damiano Anselmi

We classify the local, polynomial, unitary gauge theories that violate Lorentz symmetry explicitly at high energies and are renormalizable by weighted power counting. We study the structure of such theories and prove that renormalization does not generate higher time derivatives. We work out the conditions to renormalize vertices that are usually non-renorma

Damiano Anselmi

We study the Standard-Model extensions that have the following features: they violate Lorentz invariance explicitly at high energies; they are unitary, local, polynomial and renormalizable by weighted power counting; they contain the vertex (LH)^2, which gives Majorana masses to the neutrinos after symmetry breaking, and possibly four fermion interactions; t

I. Loris, H. Douma, G. Nolet, I. Daubechies

The effects of several nonlinear regularization techniques are discussed in the framework of 3D seismic tomography. Traditional, linear, $\ell_2$ penalties are compared to so-called sparsity promoting $\ell_1$ and $\ell_0$ penalties, and a total variation penalty. Which of these algorithms is judged optimal depends on the specific requirements of the scienti

Damiano Anselmi

We construct local, unitary gauge theories that violate Lorentz symmetry explicitly at high energies and are renormalizable by weighted power counting. They contain higher space derivatives, which improve the behavior of propagators at large momenta, but no higher time derivatives. We show that the regularity of the gauge-field propagator privileges a partic

G. W. Peters, Y. Fan, S. A. Sisson

We present a sequential Monte Carlo sampler variant of the partial rejection control algorithm, and show that this variant can be considered as a sequential Monte Carlo sampler with a modified mutation kernel. We prove that the new sampler can reduce the variance of the incremental importance weights when compared with standard sequential Monte Carlo sampler

A. Bulgarelli, M. Tavani, P. Caraveo, A. W. Chen

We present the AGILE gamma-ray observations of the field containing the puzzling gamma-ray source 3EG J1835+5918. This source is one of the most remarkable unidentified EGRET sources. An unprecedentedly long AGILE monitoring of this source yields important information on the positional error box, flux evolution, and spectrum. 3EG J1835+5918 has been in the A

Wenhui Xie, Mingli Bao, Zhenjie Zhao, Bang-Gui Liu

On experimental side, BaFe$_2$As$_2$ without doping has been made superconducting by applying appropriate pressure (2-6 GPa). Here, we use a full-potential linearized augmented plane wave method within the density-functional theory to investigate the effect of pressure on its crystal structure, magnetic order, and electronic structure. Our calculations show

Jeremie Unterberger

Let $B=(B^{(1)},B^{(2)})$ be a two-dimensional fractional Brownian motion with Hurst index $α\in (0,1/4)$. Using an analytic approximation $B(η)$ of $B$ introduced in \cite{Unt08}, we prove that the rescaled Lévy area process $(s,t)\to η^{\half(1-4α)}\int_s^t dB_{t_1}^{(1)}(η) \int_s^{t_1} dB_{t_2}^{(2)}(η)$ converges in law to $W_t-W_s$ where $W$ is a Brown

Qingfeng Li, Marcus Bleicher

HBT correlations of $π^--π^-$ pairs at FAIR/AGS energies are investigated by using the UrQMD transport model and the CRAB analyzing program. Three different possible sources (treatment of resonance lifetimes, a soft equation of state and non-Gaussian effects) to understand the HBT $R_O/R_S$ puzzle are investigated. Firstly, we find that different treatments

Alexander Barg, Arya Mazumdar, Gilles Zémor

Codes on hypergraphs are an extension of the well-studied family of codes on bipartite graphs. Bilu and Hoory (2004) constructed an explicit family of codes on regular t-partite hypergraphs whose minimum distance improves earlier estimates of the distance of bipartite-graph codes. They also suggested a decoding algorithm for such codes and estimated its erro

Marina Franz, Hannah Markwig

There is an equation relating numbers of curves on F_0 satisfying incidence conditions and numbers of curves on F_2 satisfying incidence conditions. The purpose of this paper is to give a tropical proof of this equation in the case of rational curves. We use induction on the degree and two Kontsevich-type formulas for curves on F_0 and on F_2. The formula fo

Hans Zwart

Given a Hilbert space and the generator of a strongly continuous group on this Hilbert space. If the eigenvalues of the generator have a uniform gap, and if the span of the corresponding eigenvectors is dense, then these eigenvectors form a Riesz basis (or unconditional basis) of the Hilbert space. Furthermore, we show that none of the conditions can be weak

Masatoshi Sato, Daijiro Tobe, Mahito Kohmoto

We consider a tight-binding model with the nearest neighbour hopping integrals on the honeycomb lattice in a magnetic field. Assuming one of the three hopping integrals, which we denote t_a, can take a different value from the two others, we study quantum phase structures controlled by the anisotropy of the honeycomb lattice.For weak and strong t_a regions,

Hong-Gang Luo, Dun Zhao, Xu-Gang He, Lin Li

An unstable particle in quantum mechanics can be stabilized by frequent measurements, known as the quantum Zeno effect. A soliton with dissipation behaves like an unstable particle. Similar to the quantum Zeno effect, here we show that the soliton can be stabilized by modulating periodically dispersion, nonlinearity, or the external harmonic potential availa

Shuang-Qing Wu

It is shown that the Dirac equation is separable by variables in a five-dimensional rotating Kerr-(anti-)de Sitter black hole with two independent angular momenta. A first order symmetry operator that commutes with the Dirac operator is constructed in terms of a rank-three Killing-Yano tensor whose square is a second order symmetric Stackel-Killing tensor ad

V. I. Tkach

Proposing new solution problems of the hierarchy and smallness of the cosmological constant using the Tev scale of the Standard Model in new framework of the higher-order gravity.

Fernando A. Reboredo, Randolph Q. Hood, Paul R. C. Kent

We develop a formalism and present an algorithm for optimization of the trial wave-function used in fixed-node diffusion quantum Monte Carlo (DMC) methods. We take advantage of a basic property of the walker configuration distribution generated in a DMC calculation, to (i) project-out a multi-determinant expansion of the fixed-node ground-state wave function

Thomas J. Haines

Clozel and Labesse proved the base change fundamental lemma for spherical Hecke algebras attached to an unramified group over a p-adic field. This paper proves an analogous fundamental lemma for centers of parahoric Hecke algebras attached to the same class of groups. This provides an ingredient needed for the author&#39;s program to study Shimura varieties

I. Gonzalez Hernandez, S. Kholikov, F. Hill, R. Howe

Temporal variations of the subsurface meridional flow with the solar cycle have been reported by several authors. The measurements are typically averaged over periods of time during which surface magnetic activity existed in the regions were the velocities are calculated. The present work examines the possible contamination of these measurements due to the e

Dawei Chen

Consider a component of the Hilbert scheme whose general point corresponds to a degree d genus g smooth irreducible and nondegenerate curve in a projective variety X. We give lower bounds for the dimension of such a component when X is P^3, P^4 or a smooth quadric threefold in P^4 respectively. Those bounds make sense from the asymptotic viewpoint if we fix

Sidney van den Bergh

We investigate the dependence of the luminosity-diameter relation of galaxies on the environment. This study is based on a comparison between the 80 galaxies in the Shapley-Ames Catalog that are located within a distance of 10 Mpc, and the luminosity-diameter relation for galaxies in great clusters such as Virgo and Coma. A relatively tight linear correlatio

Hye-Sung Lee

We introduce a new dark matter candidate, the lightest U-parity particle (LUP). We suggest it as a good dark matter candidate especially in the R-parity violating supersymmetric model.

L. R. G. Fontes, C. M. Newman, K. Ravishankar, E. Schertzer

The dynamical discrete web (DyDW),introduced in recent work of Howitt and Warren, is a system of coalescing simple symmetric one-dimensional random walks which evolve in an extra continuous dynamical time parameter τ. The evolution is by independent updating of the underlying Bernoulli variables indexed by discrete space-time that define the discrete web at

Takeshi Fukuyama, Nobuchika Okada

Simple supersymmetric SO(10) GUT in five dimensions is proposed, in which the fifth dimension is compactified on the $S^1/(Z_2\times Z_2^\prime)$ orbifold with two inequivalent branes at the orbifold fixed points. In this model, all matter and Higgs multiplets reside on one brane (PS brane) where the Pati-Salam (PS) symmetry is manifest, while only the SO(10

Dariusz Chruscinski, Arthur O. Pittenger

In a series of papers with Kossakowski, the first author has examined properties of densities for which the positive partial transpositrionm (PPT) property can be readily checked. These densities were also investigated from a different perspective by Baumgartner, Hiesmayr and Narnhofer. In this paper we show how the support of such densities can be expressed

X. Ke, M. L. Dahlberg, E. Morosan, J. A. Fleitman

We report systematic low temperature measurements of the DC magnetization, AC susceptibility, and heat capacity of dysprosium pyrogermanate (Dy2Ge2O7) single crystal and powder samples. Our results confirm that Dy2Ge2O7 is an anisotropic antiferromagnet. The isothermal field dependent magnetization and the integrated magnetic entropy both indicate that the D

A. S. Kirakosyan, M. Tong, T. V. Shahbazyan, Z. V. Vardeny

We study the ultrafast dynamics of surface electromagnetic waves photogenerated on aluminum film perforated with subwavelength holes array by means of transient photomodulation with 100 fs time resolution. We observed a pronounced blueshift of the resonant transmission band that reveals the important role of plasma attenuation in the dynamics and that is inc

P. C. Magalhães, M. R. Robilotta

We present a chiral model for the $J=0, I=1/2,$ elastic $K\p$ amplitude, suited to be employed in $D^+ \rar K^- \p^+ \p^+$ data analyses and valid between threshold and $1.5 $GeV. Although not as precise as other versions available in the literature, it is rather simple and incorporates the essential physics in this energy domain. In the case of the $K$-matr

Eyal Kenig, Ron Lifshitz, M. C. Cross

We study the problem of pattern selection in an array of parametrically-driven nonlinear resonators with application to microelectromechanical and nanoelectromechanical systems (MEMS & NEMS), using an amplitude equation recently derived by Bromberg, Cross, and Lifshitz [PRE 73, 016214 (2006)]. We describe the transitions between standing-wave patterns of dif

E. Pavarini, E. Koch, A. I. Lichtenstein

The Mott insulating perovskite KCuF3 is considered the archetype of an orbitally-ordered system. By using the LDA+dynamical mean-field theory (DMFT) method, we investigate the mechanism for orbital-ordering (OO) in this material. We show that the purely electronic Kugel-Khomskii super-exchange mechanism (KK) alone leads to a remarkably large transition tempe

Erin Mentuch, Alexis Brandeker, Marten H. van Kerkwijk, Ray Jayawardhana

We estimate cluster ages from lithium depletion in five pre-main-sequence groups found within 100 pc of the Sun: TW Hydrae Association, Eta Chamaeleontis Cluster, Beta Pictoris Moving Group, Tucanae-Horologium Association and AB Doradus Moving Group. We determine surface gravities, effective temperatures and lithium abundances for over 900 spectra through le

Anders Johansen, Yuri Levin

Hydromagnetic stresses in accretion discs have been the subject of intense theoretical research over the past one and a half decades. Most of the disc simulations have assumed a small initial magnetic field and studied the turbulence that arises from the magnetorotational instability. However, gaseous discs in galactic nuclei and in some binary systems are l

K. Finlator, F. Ozel, R. Dave

We introduce a new code for computing time-dependent continuum radiative transfer and non-equilibrium ionization states in static density fields with periodic boundaries. Our code solves the moments of the radiative transfer equation, closed by an Eddingtion tensor computed using a long characteristics method. We show that pure (i.e., not source-centered) sh

L. S. Borkowski

We study the model of a d-wave superconductor interacting with finite concentration of Anderson impurities at zero temperature. The interaction between impurity and conduction electrons is taken into account within the large-$N$ approximation. We discuss the obtained phase diagram and its dependence on the main energy scales.

Gonçalo A. S. Dias, José P. S. Lemos

The action for a class of three-dimensional dilaton-gravity theories, with an electromagnetic Maxwell field and a cosmological constant, can be recast in a Brans-Dicke-Maxwell type action, with its free $ω$ parameter. For a negative cosmological constant, these theories have static, electrically charged, and spherically symmetric black hole solutions. Those

Ellie D&#39;Hondt, Mehrnoosh Sadrzadeh

We propose a decision procedure for analysing security of quantum cryptographic protocols, combining a classical algebraic rewrite system for knowledge with an operational semantics for quantum distributed computing. As a test case, we use our procedure to reason about security properties of a recently developed quantum secret sharing protocol that uses grap

M. Cesetti, V. D. Ivanov, L. Morelli, A. Pizzella

Near-infrared (hereafter NIR) data may provide complementary information to the traditional optical population synthesis analysis of unresolved stellar populations because the spectral energy distribution of the galaxies in the 1-2.5\mum range is dominated by different types of stars than at optical wavelengths. Furthermore, NIR data are subjected to less ab

E. Khomenko, M. Collados

In order to understand the influence of magnetic fields on the propagation properties of waves, as derived from different local helioseismology techniques, forward modeling of waves is required. Such calculations need a model in magnetohydrostatic equilibrium as initial atmosphere to propagate oscillations through it. We provide a method to construct such a

Ridha Chatbouri

We present an unified construction for algebras and modules homologies and cohomologies, in the case of associative, commuttaive, Lie and Gerstenhaber algebras. We make a distinction between the linear part of the construction of algebras and cogebras, characterized by the symmetries of the defining relations and the structure itself which appears as a diffe