December 2007 arXiv papers — page 20

Mitya Boyarchenko

Let G be a connected unipotent group over a finite field F_q with q elements. In this article we propose a definition of L-packets of complex irreducible representations of the finite group G(F_q) and give an explicit description of L-packets in terms of the so-called "admissible pairs" for G. We then apply our results to show that if the centralizer

Vern Paulsen, Mark Tomforde

We develop a theory of ordered *-vector spaces with an order unit. We prove fundamental results concerning positive linear functionals and states, and we show that the order (semi)norm on the space of self-adjoint elements admits multiple extensions to an order (semi)norm on the entire space. We single out three of these (semi)norms for further study and dis

T. Aoyama, M. Hayakawa, T. Kinoshita, M. Nio

We have carried out a new evaluation of the eighth-order contribution to the electron g-2 using FORTRAN codes generated by an automatic code generator gencodeN. Comparison of the "new" result with the "old" one has revealed an inconsistency in the treatment of the infrared divergences in the latter. With this error corrected we now have two i

Grenville J. Croll

A small part of the Torah is arranged into a two dimensional array. The characters are then permuted using a simple recursive deterministic algorithm. The various permutations are then passed through three stochastic filters and one deterministic filter to identify the permutations which most closely approximate readable Biblical Hebrew. Of the 15 Billion se

Paolo Serra, Scott C. Trager, Tom A. Oosterloo, Raffaella Morganti

We present a study of the stellar populations of a sample of 39 local, field early-type galaxies whose HI properties are known from interferometric data. Our aim is to understand whether stellar age and chemical composition depend on the HI content of galaxies. As a by-product of our analysis, we also study their ionised gas content and how it relates to the

Frederick A. Harris

Using 58 million $J/ψ$ and 14 million $ψ(2S)$ events collected by the BESII detector at the BEPC, branching fractions or upper limits for the decays $J/ψ$ and $ψ(2S) \to Λ\barΛ π^0$ and $Λ\barΛ η$ are measured, and the decays of $J/ψ$ and $ψ(2S)$ to $n K^0_S \barΛ+c.c.$ are observed and measured for the first time. Finally, $R$ measurement data taken with th

Avi M. Mandell

This review focuses on recent results in advancing our understanding of the location and distribution of habitable exo-Earth environments. We first review the qualities that define a habitable planet/moon environment. We extend these concepts to potentially habitable environments in our own Solar System and the current and future searches for biomarkers ther

E. Agliari, R. Burioni, D. Cassi, F. M. Neri

We consider a population of $N$ labeled random walkers moving on a substrate, and an excitation jumping among the walkers upon contact. The label $\mathcal{X}(t)$ of the walker carrying the excitation at time $t$ can be viewed as a stochastic process, where the transition probabilities are a stochastic process themselves. Upon mapping onto two simpler proces

A. G. Shkvarunets, R. B. Fiorito

We have developed a novel method based on vector electromagnetic theory and Schellkunoff's principles to calculate the spectral and angular distributions of transtion radiation (TR) and diffraction radiation (DR) produced by a charged particle interacting with an arbitrary target. The vector method predicts the polarization and spectral angular distribut

T. Bloom, N. Levenberg

We provide a general framework and indicate relations between the notions of transfinite diameter, homogeneous transfinite diameter, and weighted transfinite diameter for sets in C^N. An ingredient is a formula of Rumely which relates the Robin function and the transfinite diameter of a compact set. We also prove limiting formulas for integrals of generalize

Sergei Elyutin, Sergei Ozhenko, Andrei Maimistov

The refraction is theoretically considered of ultimately short pulses at interface of two dielectrics that contains a thin film of nonlinear metamaterial. For the model of metamaterial composed of nanoparticles and magnetic nanocircuits (split-ring resonators) the equations are obtained suitable for describing the coherent responses of such film. The numeric

Shahar Even-Dar Mandel, Ron Lifshitz

Understanding the electronic properties of quasicrystals, in particular the dependence of these properties on dimension, is among the interesting open problems in the field of quasicrystals. We investigate an off-diagonal tight-binding Hamiltonian on the separable square and cubic Fibonacci quasicrystals. We use the well-studied singular-continuous energy sp

D. O. Soares-Pinto, W. A. M. Morgado

Using a time-averaging technique we obtain exactly the probability distribution for position and velocity of a Brownian particle under the influence of two heat baths at different temperatures. These baths are expressed by a white noise term, representing the fast dynamics, and a colored noise term, representing the slow dynamics. Our exact solution scheme a

Zajj Daugherty, Alexander K. Eustis, Gregory Minton, Michael E. Orrison

We show how voting may be viewed naturally from an algebraic perspective by viewing voting profiles as elements of certain well-studied $\mathbb{Q}S_n$-modules. By using only a handful of simple combinatorial objects (e.g., tabloids) and some basic ideas from representation theory (e.g., Schur's Lemma), this allows us to recast and extend some well-known

Hari P. Dahal, Jean-Pierre Julien, A. V. Balatsky

We use the Gutzwiller method to investigate the importance of the on-site Coulomb interaction in graphene. We apply it to Hubbard Hamiltonian to study the renormalization of the kinetic energy in graphene due to the on-site Coulomb interaction. We find that a reasonable strength of the interaction has a very weak effect in reducing the kinetic energy. Hence

Valentina D'Odorico, Miroslava Dessauges-Zavadsky

We briefly review the main results obtained in the field of QSO absorption line studies with the UVES high resolution spectrograph mounted on the Kueyen unit of the ESO Very Large Telescope (Paranal, Chile).

Lara Faoro, Lev B. Ioffe

We analyze the data and discuss their implications for the microscopic origin of the low frequency flux noise in superconducting circuits. We argue that this noise is produced by spins at the superconductor insulator boundary whose dynamics is due to RKKY interaction. We show that this mechanism explains size independence of the noise, different frequency de

Mohamed Boucetta

We compute the eigenvalues with multiplicities of the Lichnerowicz Laplacian acting on the space of complex symmetric covariant tensor fields on the complex projective space $P^n(\comp)$. The spaces of symmetric eigentensors are explicitly given.

S. B. Cenko, D. B. Fox, B. E. Penprase, A. Cucchiara

We present the discovery and high signal-to-noise spectroscopic observations of the optical afterglow of the long-duration gamma-ray burst GRB070125. Unlike all previously observed long-duration afterglows in the redshift range 0.5 < z < 2.0, we find no strong (rest-frame equivalent width W > 1.0 A) absorption features in the wavelength range 4000 - 10000 A.

Albena I. Nielsen, Tage Christensen, Bo Jakobsen, Kristine Niss

We present data for the dielectric relaxation of 43 glass-forming organic liquids, showing that the primary (alpha) relaxation is often close to square-root-time relaxation. The better an inverse power-law description of the high-frequency loss applies, the more accurately is square-root-time relaxation obeyed. These findings suggest that square-root-time re

Masaomi Tanaka, Paolo A. Mazzali, Stefano Benetti, Ken&#39;ichi Nomoto

The properties of the highest velocity ejecta of normal Type Ia supernovae (SNe Ia) are studied via models of very early optical spectra of 6 SNe. At epochs earlier than 1 week before maximum, SNe with a rapidly evolving Si II 6355 line velocity (HVG) have a larger photospheric velocity than SNe with a slowly evolving Si II 6355 line velocity (LVG). Since th

Claudia de Rham, Stefan Hofmann, Justin Khoury, Andrew J. Tolley

We construct a cascading brane model of gravity in which the behavior of the gravitational force law interpolates from (n+4)-dimensional to (n+3)-dimensional all the way down to 4-dimensional from longer to shorter length scales. We show that at the linearized level, this model exhibits the features necessary for degravitation of the cosmological constant. T

Pavel Kroupa

Most stars form in dense star clusters deeply embedded in residual gas. These objects must therefore be seen as the fundamental building blocks of galaxies. With this contribution some physical processes that act in the very early and also later dynamical evolution of dense stellar systems in terms of shaping their later appearance and properties, and the im

Jan Petter Morten, Arne Brataas, Gerrit E. W. Bauer, Wolfgang Belzig

The injection of pure spin current into superconductors by the dynamics of a ferromagnetic contact is studied theoretically. Taking into account suppression of the order parameter at the interfaces (inverse proximity effect) and the energy-dependence of spin-flip scattering, we determine the temperature-dependent ferromagnetic resonance linewidth broadening.

S. Hossenfelder

The aim of this note is to address the low energy limit of quantum field theories with a minimal length scale. The essential feature of these models is that the minimal length acts as a regulator in the asymptotic high energy limit which is incorporated through an infinite series of higher order derivatives. If one investigates a perturbative expansion in in

Robert Seiringer, Jun Yin

We derive a lower bound on the ground state energy of the Hubbard model for given value of the total spin. In combination with the upper bound derived previously by Giuliani, our result proves that in the low density limit, the leading order correction compared to the ground state energy of a non-interacting lattice Fermi gas is given by $8πa ρ_u ρ_d$, where

Xiaohua Wu, Hui Cao

We measured the ensemble-averaged spectral correlation functions and statistical distributions of spectral spacing and intensity for lasing modes in weakly scattering systems, and compared them to those of the amplified spontaneous emission spikes. Their dramatic differences illustrated the distinct physical mechanisms. Our numerical simulation revealed that

Marco Battaglia, Jean-Marie Bussat, Devis Contarato, Peter Denes

This paper presents the design and results of detailed tests of a CMOS active pixel chip for charged particle detection with in-pixel charge storage for correlated double sampling and readout in rolling shutter mode at frequencies up to 25 MHz. This detector is developed in the framework of R&D for the Vertex Tracker for the International Linear Collider.

M. Evaldsson, S. Ihnatsenka, I. V. Zozoulenko

We study spin polarization in a split-gate quantum wire focussing on the effect of a realistic smooth potential due to remote donors. Electron interaction and spin effects are included within the density functional theory in the local spin density approximation. We find that depending on the electron density, the spin polarization exhibits qualitatively diff

Wouter J. T. Bos, Jean-Pierre Bertoglio

The evolution of the turbulent energy spectrum for the inviscid spectrally truncated Euler equations is studied by closure calculations. The observed behavior is similar to the one found in direct numerical simulations [Cichowlas, Bonaïtiti, Debbasch, and Brachet, Phys. Rev. Lett. 95, 264502 (2005)]. A Kolmogorov spectral range and an equipartition range are

Wouter J. T. Bos, L. Shao, Jean-Pierre Bertoglio

The normalized turbulent dissipation rate $C_ε$ is studied in decaying and forced turbulence by direct numerical simulations, large-eddy simulations, and closure calculations. A large difference in the values of $C_ε$ is observed for the two types of turbulence. This difference is found at moderate Reynolds number, and it is shown that it persists at high Re

Daniel Sudarsky

This paper contains a critique of the standard inflationary account of the origin of cosmological structures from quantum fluctuations in the early universe. This critique can be thought to be purely philosophical in nature, but I prefer to view it, rather, as arising from the need to put the interpretational aspects of the theory -which quite obviously lie

Sun-Yung A. Chang, Jie Qing, Paul Yang

This is a survey paper of our current research on the theory of partial differential equations in conformal geometry. Our intention is to describe some of our current works in a rather brief and expository fashion. We are not giving a comprehensive survey on the subject and references cited here are not intended to be complete. We introduce a bubble tree str

Miklos Bona

We prove that the number of copies of any given permutation pattern $q$ has an asymptotically normal distribution in random permutations.

B. J. Wargelin, V. L. Kashyap, J. J. Drake, D. García-Alvarez

We present results from two Chandra imaging observations of Ross 154, a nearby flaring M dwarf star. During a 61-ks ACIS-S exposure, a very large flare occurred (the equivalent of a solar X3400 event, with L_X = 1.8x10^30 ergs/s) in which the count rate increased by a factor of over 100. The early phase of the flare shows evidence for the Neupert effect, fol

J. Ledieu, L. Leung, L. H. Wearing, R. McGrath

A quasiperiodic Pb monolayer has been formed on the five-fold surface of the Al-Pd-Mn quasicrystal. Growth of the monolayer proceeds via self-assembly of an interconnected network of pentagonal Pb stars, which are shown to be tau-inflated compared to similar structural elements of the quasiperiodic substrate. Measurements of the electronic structure of the s

Xavier Cabre, Antonio Capella, Manel Sanchon

We consider semi-stable, radially symmetric, and decreasing solutions of a reaction equation involving the p-Laplacian, where the reaction term is a locally Lipschitz function, and the domain is the unit ball. For this class of radial solutions, which includes local minimizers, we establish pointwise and Sobolev estimates which are optimal and do not depend

Laszlo B Szabados

The eigenvalue problem for the Sen--Witten operator on closed spacelike hypersurfaces is investigated. The (square of its) eigenvalues are shown to be given exactly by the 3-surface integral appearing in the expression of the total energy-momentum of the matter+gravity systems in Witten&#39;s energy positivity proof. A sharp lower bound for the eigenvalues,

Xiaojuan Shi, Alejandra Valencia, Martin Hendrych, Juan P. Torres

We describe a new scheme to fully control the joint spectrum of paired photons generated in spontaneous parametric down-conversion. We show the capability of this method to generate frequency-uncorrelated photon pairs that are pure and indistinguishable, and whose bandwidth can be readily tuned. Importantly, the scheme we propose here can be implemented in a

Mikito Koshino, Tsuneya Ando

We present a theoretical study on the orbital magnetism in multilayer graphenes within the effective mass approximation. The Hamiltonian and thus susceptibility can be decomposed into contributions from sub-systems equivalent to monolayer or bilayer graphene. The monolayer-type subband exists only in odd layers and exhibits a delta-function susceptibility at

A. E. Myasnikova, E. N. Myasnikov

Common approach is used to calculate band due to strong-coupling large polaron (SCLP) photodissociation in ARPES and in optical conductivity (OC) spectra. It is based on using the coherent-states representation for the phonon field in SCLP. The calculated positions of both band maximums are universal functions of one parameter - the SCLP binding energy Ep: A

John Ellis, N. E. Mavromatos, D. V. Nanopoulos, A. S. Sakharov

We correct the fitting formula used in refs. [1,2] to obtain a robust limit on a violation of Lorentz invariance that depends linearly on the photon energy. The correction leads to a slight increase of the limit on the scale of the violation, to M > 1.4 x 10^{16} GeV.

Asif ud-Doula, Stanley Owocki, Richard Townsend

Building upon our previous MHD simulation study of magnetic channeling in radiatively driven stellar winds, we examine here the additional dynamical effects of stellar {\em rotation} in the (still) 2-D axisymmetric case of an aligned dipole surface field. In addition to the magnetic confinement parameter $η_{\ast}$ introduced in Paper I, we characterize the

Michael D. Koenig, Stefano Battiston, Frank Schweitzer

We develop a new framework for modeling innovation networks which evolve over time. The nodes in the network represent firms, whereas the directed links represent unilateral interactions between the firms. Both nodes and links evolve according to their own dynamics and on different time scales. The model assumes that firms produce knowledge based on the know

E. Bayet, S. Viti, D. A. Williams, J. M. C. Rawlings

Hot core molecules should be detectable in external active galaxies out to high redshift. We present here a detailed study of the chemistry of star-forming regions under physical conditions that differ significantly from those likely to be appropriate in the Milky Way Galaxy. We examine, in particular, the trends in molecular abundances as a function of time

P. Artoisenet, F. Maltoni, T. Stelzer

We present a simple method to automatically evaluate arbitrary tree-level amplitudes involving the production or decay of a heavy quark pair QQbar in a generic {2S+1}L_J^[1,8] state, i.e., the short distance coefficients appearing in the NRQCD factorization formalism. Our approach is based on extracting the relevant contributions from the open heavy quark-an

L. A. Glinka

The Einstein-Friedmann Universe as whole quantum object can be treated as bosonic string mass groundstate, called a tachyon, having negative mass square and a speed more than the speed of light. I present a brief review of results obtained from this point of view called Many-Particle Quantum Gravity approach - the monodromy problem in the Fock space, thermod

G. Seth Roberts, Rodrigo Sanchez, Roger Kemp, Tiffany Wood

Colloids dispersed in a non-polar solvent become charged when reverse micelles are added. We study the charge of individual sterically-stabilized poly(methyl methacrylate) spheres dispersed in micellar solutions of the surfactants sodium bis(2-ethyl 1-hexyl) sulfosuccinate [AOT], zirconyl 2-ethyl hexanoate [Zr(Oct)$_{2}$], and a copolymer of poly(12-hydroxys

Teemu Ojanen, Antti-Pekka Jauho

We show that the heat transport between two bodies, mediated by electromagnetic fluctuations, can be controlled with an intermediate quantum circuit - leading to the device concept Mesoscopic Photon Heat Transistor (MPHT). Our theoretical analysis is based on a novel Meir-Wingreen-Landauer type of conductance formula, which gives the photonic heat current th

B. Abdullaev, U. Rössler, C. -H. Park

In our recent paper (Phys. Rev. B 76, 075403 (2007)), we have applied the anyon concept to derive an approximate analytic formula for the ground state energy, which applies to two-dimensional (2D) Coulomb systems from the bosonic to the fermionic limit. We make use of these results here to draw attention to correlation effects for two special cases: the spin

A. Gomez Nicola, J. R. Pelaez, G. Rios

The Inverse Amplitude Method is a powerful unitarization technique to enlarge the energy applicability region of Effective Lagrangians. It has been widely used to describe resonances from Chiral Perturbation Theory as well as for the Strongly Interacting Symmetry Breaking Sector. In this work we show how it can be slightly modified to account also for the su

M. Czakon, T. Schutzmeier

We compute the virtual O(α_s^3 n_f^2) corrections to the heavy quark vector current correlator in terms of expansions in the external momentum and as an exact numerical solution. As a byproduct, the available high-energy expansion at the three-loop level is extended.

C. Sasaki, B. Friman, K. Redlich

The thermodynamics of a first order chiral phase transition is considered in the presence of spinodal phase separation within the Nambu-Jona-Lasinio (NJL) model. The properties of the basic thermodynamic observables in the coexistence phase are discussed for zero and non-zero quark masses. We focus on observables that probe the chiral phase transition. In pa

Patrick Petitjean, Cedric Ledoux, R. Srianand

We study the Oxygen and Nitrogen abundances in the interstellar medium of high-redshift galaxies. We use high resolution and high signal-to-noise ratio spectra of Damped Lyman-alpha (DLA) systems detected along the line-of-sight to quasars to derive robust abundance measurements from unsaturated metal absorption lines. We present results for a sample of 16 h

E. Dwek, R. G. Arendt, P. Bouchet, D. N. Burrows

Multiwavelength observations of supernova remnant (SNR) 1987A show that its morphology and luminosity are rapidly changing at X-ray, optical, infrared, and radio wavelengths as the blast wave from the explosion expands into the circumstellar equatorial ring, produced by mass loss from the progenitor star. The observed infrared (IR) radiation arises from the

Julia Rausenberger, Christian Fleck, Jens Timmer, Markus Kollmann

Noise in gene expression, either due to inherent stochasticity or to varying inter- and intracellular environment, can generate significant cell-to-cell variability of protein levels in clonal populations. We present a theoretical framework, based on stochastic processes, to quantify the different sources of gene expression noise taking cell division explici

P. J. E. Peebles

The relativistic LambdaCDM cosmological model has passed a demanding network of tests that convincingly demonstrate it is a useful approximation to what happened back to high redshift. But there are anomalies in its application to structure formation on the scales of galaxies that show we have much to learn about what this theory actually predicts and possib

Claudio Fontanari

We prove that if $m \ge n-3$ then every $S_m$-invariant F-nef divisor on the moduli space of stable $n$-pointed curves of genus zero is linearly equivalent to an effective combination of boundary divisors. As an application, we determine the Mori cone of the moduli spaces of stable curves of small genus with few marked points.

Jingjing Zhang, Yu Luo, Hongsheng Chen, Lixin Ran

We use coordinate transformation theory to realize substrates that can modify the emission of an embedded source. Simulation results show that with proper transformation functions the energy radiated by a source embedded in these space variant media will be concentrated in a narrow beam. The thickness of the slab achieved with our transformations will no lon

Jacco Th. van Loon

This review discusses some of the observational constraints on what we know about the mass loss experienced by stars in the Asymptotic Giant Branch (AGB) phase of evolution. Mass loss affects the maximum mass attained by the core of an AGB star and hence its fate as a white dwarf or potentially a supernova. The way mass loss depends on stellar initial parame

Michael D. Koenig, Stefano Battiston, Mauro Napoletano, Frank Schweitzer

We investigate some of the properties and extensions of a dynamic innovation network model recently introduced in \citep{koenig07:_effic_stabil_dynam_innov_networ}. In the model, the set of efficient graphs ranges, depending on the cost for maintaining a link, from the complete graph to the (quasi-) star, varying within a well defined class of graphs. Howeve

Fraser Lewis, David M. Russell, Rob P. Fender, Paul Roche

We have been undertaking a monitoring project of 13 low-mass X-ray binaries (LMXBs) using FT North since early 2006. The introduction of FT South has allowed us to extend this monitoring to include 15 southern hemisphere LMXBs. With new instrumentation, we also intend to expand this monitoring to include both infrared wavelengths and spectroscopy.

Persi Diaconis, Svante Janson

We develop a clear connection between deFinetti&#39;s theorem for exchangeable arrays (work of Aldous--Hoover--Kallenberg) and the emerging area of graph limits (work of Lovasz and many coauthors). Along the way, we translate the graph theory into more classical probability.

B. Abdullaev, U. Rössler, C. -H. Park

We present analytic formulas for the ground state energy of the two-dimensional (2D) anyon gas in the quantum limit of a perpendicular magnetic field (Landau level filling factor ν_L\le 1). These formulas, for the cases without and with Coulomb interaction, are obtained by applying the harmonic potential regularization for vanishing confinement to the harmon

R. Bindu, Kalobaran Maiti, R. Rawat, S. Khalid

We investigate the interplay of the electronic and structural transition in La$_{0.2}$Sr$_{0.8}$MnO$_{3}$. The transport and specific heat measurements exhibit unusual evolutions and signature of a first order phase transition around 265 K. Mn K-edge extended $x$-ray absorption fine structure results reveal distortion in the MnO$_6$ octahedra even in the cub

O. Kochukhov, N. Piskunov

We present a new implementation of the magnetic Doppler imaging technique, which aims at self-consistent temperature and magnetic mapping of the surface structures in cool active stars. Our magnetic imaging procedure is unique in its capability to model individual spectral features in all four Stokes parameters. We discuss performance and intrinsic limitatio

Philip Yock

Data from LEP2 on hadron production in gamma gamma interactions at high pT exceed the predictions of QCD by about an order of magnitude. The amplitude for the process is asymptotically proportional to the sum of the squares of the charges of quarks. The data are suggestive of models where quarks have unit charges, or larger. Unequivocal tests could be made w

Gelu Popescu

In this paper, we initiate the study of sub-pluriharmonic curves in Cuntz-Toeplitz algebras and free pluriharmonic majorants on noncommutative balls. We are lead to a characterization of the noncommutative Hardy space $H^2_{\bf ball}$ in terms of free pluriharmonic majorants, and to a Schur type description of the unit ball of $H^2_{\bf ball}$. These results

Kim Henriksen, Gourinath Banda, John Gallagher

Convex polyhedral abstractions of logic programs have been found very useful in deriving numeric relationships between program arguments in order to prove program properties and in other areas such as termination and complexity analysis. We present a tool for constructing polyhedral analyses of (constraint) logic programs. The aim of the tool is to make avai

T. D. Palev

It is shown that the statistics of the hardcore fermions is A-superstatistics of order one [see T.D.P. J. Math. Phys. 21, 1293 (1980)]. The Pauli principle for these particles is formulated. The Hubbard operators, which constitute a basis in the Lie superalgebra gl(1|n), are expressed via the creation and the annihilation operators of the hardcore fermions.

J. Gracia, S. Bogovalov, K. Tsinganos

We present a self-consistent MHD model for the jet of M87. The model consist of two distinct zones: an inner relativistic outflow, which we identify with the observed jet, and an outer cold disk-wind. While the former does not self-collimate efficiently due to its high effective inertia, the latter fulfills all the conditions for efficient collimation by the

L. Willingale, S. P. D. Mangles, P. M Nilson, R. J. Clarke

Longitudinal ion acceleration from high-intensity (I ~ 10^20 Wcm^-2) laser interactions with helium gas jet targets (n_e ~ 0.04 n_c) have been observed. The ion beam has a maximum energy for He^2+ of approximately 40 MeV and was directional along the laser propagation path, with the highest energy ions being collimated to a cone of less than 10 degrees. 2D p

Eugene H. Kim, Ö. Legeza, J. Sólyom

We consider topological order and dimer order in several frustrated spin ladder models, which are related to higher dimensional models of current interest; we also address the occurrence of fractionalized phases with deconfined spinon excitations in these models. Combining results obtained with both analytic and numerical methods, we discuss how the occurren

Will J. Percival, Bjoern M. Schaefer

Galaxy bias can be split into two components: a formation-bias based on the locations of galaxy creation, and an evolution-bias that details their subsequent evolution. In this letter we consider evolution-bias in the peaks model. In this model, galaxy formation takes place at local maxima in the density field, and we analyse the subsequent peculiar motion o

K. Kowalski, J. Rembielinski, K. A. Smolinski

We discuss the limit T->0 of the relativistic ideal Fermi gas of luxons (particles moving with the speed of light) and tachyons (hypothetical particles faster than light) based on observations of our recent paper: K. Kowalski, J. Rembielinski and K.A. Smolinski, Phys. Rev. D, 76, 045018 (2007). For bradyons this limit is in fact the nonrelativistic one and t

Yuri Kornyushin

Usually microscopic electrostatic field around ions is neglected when the ionization energy is concerned. The ionization energy is considered to be equal to that of a separate atom (molecule). Here the energy of the electrostatic field around ions is taken into account. It is shown that the energy of this field contributes to decrease in the effective ioniza

Igor V. Chilingarian, Gary A. Mamon

We report the discovery of a compact object (R_e = 32 pc, M_B = -12.34 mag) at a projected distance of 9 kpc from Messier 59, a giant elliptical in the Virgo cluster. Using HST imaging and SDSS spectroscopy, both available in the Virtual Observatory, we find that this object has a blue core containing one-quarter of the light, and a redder n=1 Sersic envelop

P. V. Paluskar, J. J. Attema, G. A. de Wijs, S. Fiddy

We provide compelling evidence to establish that, contrary to one&#39;s elementary guess, the tunneling spin polarization (TSP) of amorphous CoFeB is larger than that of highly textured fcc CoFeB. First principles atomic and electronic structure calculations reveal striking agreement between the measured TSP and the predicted s-electron spin polarization. Gi

F. Haberl, W. Pietsch

Early X-ray surveys of the Magellanic Clouds (MCs) were performed with the imaging instruments of the Einstein, ASCA and ROSAT satellites revealing discrete X-ray sources and large-scale diffuse emission. Large samples of supernova remnants, high and low mass X-ray binaries and super-soft X-ray sources could be studied in detail. Today, the major X-ray obser

Kate Marvel, Neil Turok

In the thin-wall approximation, the decay of a gravitating false vacuum to a lower-energy state is affected by the cosmological horizon structure in both spaces. The nucleation radius of a bubble of true vacuum depends on the surface tension of its boundary and equals the false vacuum cosmological horizon at a critical tension. We argue that there is no tunn

A. Chatzistavrakidis, P. Manousselis, N. Prezas, G. Zoupanos

In the present contribution we extend our previous work by considering the coset space dimensional reduction of higher-dimensional Einstein--Yang--Mills theories including scalar fluctuations as well as Kaluza--Klein excitations of the compactification metric and we describe the gravity-modified rules for the reduction of non-abelian gauge theories.

Santo Fortunato, Claudio Castellano

Graph vertices are often organized into groups that seem to live fairly independently of the rest of the graph, with which they share but a few edges, whereas the relationships between group members are stronger, as shown by the large number of mutual connections. Such groups of vertices, or communities, can be considered as independent compartments of a gra

S. Maurogordato, A. Cappi, C. Ferrari, C. Benoist

We present a detailed optical analysis of the galaxy cluster A2163 based on new multicolor wide field imaging and medium-to-high resolution (R~2000) spectroscopy. While X-ray observations have revealed that merging processes are present in this cluster, the merging scenario is complex and not well-defined. We undertook a complementary optical analysis, aimin

W. Schattke, E. E. Krasovskii, R. Díez Muiño, P. M. Echenique

Non-linear effects in photoemission are shown to open a new access to the band structure of unoccupied states in solids, totally different from hitherto used photoemission spectroscopy. Despite its second-order nature, strong resonant transitions occur, obeying exact selection rules of energy, crystal symmetry, and momentum. Ab-initio calculations are used t

Ido Kanter, Evi Kopelowitz, Johannes Kestler, Wolfgang Kinzel

Two chaotic systems which interact by mutually exchanging a signal built from their delayed internal variables, can synchronize. A third unit may be able to record and to manipulate the exchanged signal. Can the third unit synchronize to the common chaotic trajectory, as well? If all parameters of the system are public, a proof is given that the recording sy

B. S. Kerner, S. L. Klenov, A. Brakemeier

A testbed for wireless vehicle communication based on a microscopic model in the framework of three-phase traffic theory is presented. In this testbed, vehicle motion in traffic flow and analyses of a vehicle communication channel access based on IEEE 802.11e mechanisms, radio propagation modeling, message reception characteristics as well as all other effec

Jacques Soffer

Our knowledge of the nucleon spin structure has greatly improved over the last twenty years or so, but still many fundamental questions remain unsolved. I will try to review some of the puzzling aspects of the structure of the nucleon spin, in particular, what is known, what remains to be discovered and the prospects for the near future. I will also focus on

S. Drenska, M. I. Ivanov, N. Minkov

A systematics of the atomic nuclei in the frame of the nucleon number $A = Z + N$ and the proton-neutron difference $F = Z - N$ is considered. The classification scheme is provided by means of the non-compact algebra $sp(4,R)$. In this scheme the nuclei are ordered into isobaric multiplets, for which $A={fix}$, as well as in F-multiplets, for which $F={fix}$

Daniele Binosi, Joannis Papavassiliou

We present a new truncation scheme for the Schwinger-Dyson equations of QCD that respects gauge invariance at any level of the dressed loop expansion. When applied to the gluon self-energy, it allows for its non-perturbative treatment without compromising the transversality of the solution, even when entire sets of diagrams (most notably the ghost loops) are

T. Jana, P. Roy

Using first and second order supersymmetry formalism we obtain a class of exactly solvable potentials subject to moving boundary conditions.

Antonio Trovato, Trinh X. Hoang, Jayanth R. Banavar, Amos Maritan

Packing problems have been of great interest in many diverse contexts for many centuries. The optimal packing of identical objects has been often invoked to understand the nature of low temperature phases of matter. In celebrated work, Kepler conjectured that the densest packing of spheres is realized by stacking variants of the face-centered cubic lattice a

Fernando Parisio

By using the localized character of canonical coherent states, we give a straightforward derivation of the Bargmann integral representation of Wigner function (W). A non-integral representation is presented in terms of a quadratic form V*FV, where F is a self-adjoint matrix whose entries are tabulated functions and V is a vector depending in a simple recursi

V. V. Pipin

The consequences of the shear-induced alpha effect to the long-term modulation of magnetic activity are examined with the help of the axisymmetric numerical dynamo model that includes the self-consistent description of the angular momentum balance, heat transport and magnetic field generation in the spherical shell. We find that the shear contributions to al

D. Djukanovic, J. Gegelia, S. Scherer, M. R. Schindler

We consider a symmetry-preserving approach to the nucleon-nucleon scattering problem in the framework of the higher-derivative formulation of baryon chiral perturbation theory. Within this framework the leading-order amplitude is calculated by solving renormalizable equations and corrections are taken into account perturbatively.

Radoslaw Wojtak, Ewa L. Lokas

Using an example of the Abell 2634 galaxy cluster we discuss the effect of contamination of kinematic data by interlopers and its impact on mass modelling. The cluster data reveal rich substructure along the line of sight. We demonstrate that it is necessary to apply a few independent methods of interloper removal in order to obtain a reliable sample of clus

Paulo M. Sá, Alfredo B. Henriques

We investigate the production of gravitational waves due to quantum fluctuations of the vacuum during the transition from the inflationary to the radiation-dominated eras of the universe, assuming this transition to be dominated by the phenomenon of parametric resonance. The energy spectrum of the gravitational waves is calculated using the method of continu

Graham Everest, Patrick Ingram, Valery Mahe, Shaun Stevens

An elliptic divisibility sequence, generated by a point in the image of a rational isogeny, is shown to possess a uniformly bounded number of prime terms. This result applies over the rational numbers, assuming Lang&#39;s conjecture, and over the rational function field, unconditionally. In the latter case, a uniform bound is obtained on the index of a prime

Jiang-Feng Du, Jing Zhu, Ming-Guang Hu, Jing-Ling Chen

In two-dimensions, the laws of physics even permit the existence of anyons which exhibit fractional statistics ranging continuously from bosonic to fermionic behaviour. They have been responsible for the fractional quantum Hall effect and proposed as candidates for naturally fault-tolerant quantum computation. Despite these remarkable properties, the fractio

Eduardo Bica, Charles Bonatto

We study the nature of the globular cluster (GC) candidates FSR 1603 and FSR 1755 selected from the catalogue of \citet{FSRcat}. Their properties are investigated with 2MASS field-star decontaminated photometry, which is used to build colour-magnitude diagrams (CMDs), and stellar radial density profiles (RDPs). FSR 1603 has the open cluster (OC) Ruprecht 101

A. N. Vasiliev, V. V. Mochalov, S. I. Alekhin, N. A. Bazhanov

The new polarization program SPASCHARM is being prepared in Protvino. The program has two stages. The first stage is dedicated to single-spin asymmetries in the production of miscellaneous light resonances with the use of 34 GeV $π^-$-beam. Inclusive and exclusive reactions will be studied simultaneously. The second stage is dedicated to single-spin and doub