September 2004 arXiv papers — page 7

Kamal Lochan Panigrahi

In this thesis we discuss some nonperturbative and noncommutative aspects of string theory. We present low-energy background field solutions corresponding to various D-branes (and their bound states) and intersecting branes in flat and pp-wave spacetime. A class of D-brane bound states are constructed from charged macroscopic strings and they are shown to sa

Ulf H. Danielsson

In these lectures I review recent attempts to apply string theory to cosmology, including string cosmology and various models of brane cosmology. In addition, the review includes an introduction to inflation as well as a discussion of transplanckian signatures. I also provide a critical discussion of the possible role of holography. The material is based on

Ian Balitsky

The cross section of heavy-ion collisions is represented as a double functional integral with the saddle point being the classical solution of the Yang-Mills equations with boundary conditions/sources in the form of two shock waves corresponding to the two colliding ions. I develop the expansion of this classical solution in powers of the commutator of the W

John C. Collins, Davison E. Soper, George Sterman

We summarize the standard factorization theorems for hard processes in QCD, and describe their proofs.

A. A. Arkhipov

We give an analysis of the experimental material presented by the SELEX Collaboration to find the true place for the SELEX state $D_{sJ}^+$(2632) in the unified picture for hadron spectra developed early. It is found that the SELEX measurements are excellently incorporated in the unified picture for hadron spectra. Our analysis shows that the measured values

D. Toublan, John B. Kogut

We use a hadron resonance gas model to study the QCD phase diagram at nonzero temperature, baryon, isospin and strangeness chemical potentials. We determine the temperature of the transition from the hadronic phase to the quark gluon plasma phase using two different methods. We find that the critical temperatures derived in both methods are in very good agre

Michael G. Albrow

I introduce the critical pomeron theory ("white pomeron") proposed by Alan White, with its prediction of excessive WW and ZZ production at the LHC especially by double pomeron exchange (DPE), which is a crucial test. This theory implies dramatic effects in cosmic rays, possibly explaining the knee and high ET jet excesses. Some of the ultra high ener

Stephen Godfrey, Shou-Hua Zhu, M. A. Doncheski

We studied single Higgs boson production in $γγ$ collisions proceeding via the hadronic content of the photon. For SM Higgs masses of current theoretical interest, the resolved photon contributions are non-negligible in precision cross section measurements. We found that production of the heavier Higgs bosons H^0 and A^0 of the MSSM can probe regions of the

Frank Deppisch, Heinrich Päs, Jouni Suhonen

We discuss the relation between the absolute neutrino mass scale, the effective mass measured in neutrinoless double beta decay, and the Majorana CP phases. Emphasis is placed on estimating the upper bound on the nuclear matrix element entering calculations of the double beta decay half life. Consequently, one of the Majorana CP phases can be constrained whe

M. Beyer, S. Christ, E. Schmidt, H. Schroeder

Effective anomalous quartic gauge couplings on tree level appear, e.g., in a strong interacting Higgs scenario. We present a status report on our study on triple boson production sensitive to these couplings. The study is done for parameters of a future linear collider.

Gudrun Heinrich, Bernd A. Kniehl

We study the photoproduction of a D^{*+-} meson in association with a hadron jet at next-to-leading order in the parton model of QCD with non-perturbative fragmentation functions extracted from LEP1 data of e^+e^- annihilation. The transverse-momentum and rapidity distributions recently measured at DESY HERA in various kinematic ranges nicely agree with our

S. S. Bulanov, A. M. Fedotov, F. Pegoraro

The problem of the backreaction during the process of electron-positron pair production by a circularly polarized electromagnetic wave propagating in a plasma is investigated. A model based on the relativistic Boltzmann-Vlasov equation with a source term corresponding to the Schwinger formula for the pair creation rate is used. The damping of the wave, the n

Hiroki Nakamura, Ryoichi Seki, Makoto Sakuda

We carry out a relativistic calculation of the cross sections of electron-16O and -12C quasi-elastic scattering and quasi-free Delta production and compare with the (e,e') data systematically in the wide energy range of 0.5 - 1.5 GeV. Using the same formalism, we examine the mu-neutrino quasi-elastic scattering from 16O. The model incorporating the nucle

A. D. Dolgov, Fuminobu Takahashi

It is shown that hypothetical neutrino-majoron coupling can suppress neutrino flavor oscillations in the early universe, in contrast to the usual weak interaction case. This reopens a window for a noticeable cosmological lepton asymmetry which is forbidden for the large mixing angle solution in the case of standard interactions of neutrinos.

M. M. Islam, R. J. Luddy, A. V. Prokudin

We predict pp elastic differential cross section at LHC at the c.m. energy sqrt(s) = 14 TeV and momentum transfer range |t| = 0 - 10 GeV^2, which is planned to be measured by the TOTEM group. The field theory model underlying our phenomenological investigation describes the nucleon as a composite object with an outer cloud of quark-antiquark condensate, an i

Alp Deniz Özer

We discuss the vacuum energy density term resulting from the spontaneous breakdown of the electroweak gauge symmetry, in the Higgs Mechanism. We alternatively expand the scalar field at one of the degenerate states that lie outside the circle of minimum, such that the Higgs Potential becomes free of any constant field term, and describes a true vacuum. We sh

Jorge Casalderrey-Solana, Edward V. Shuryak

Recently there was a significant change of views on physical properties and underlying dynamics of Quark-Gluon Plasma at $T=170-350 MeV$, produced in heavy ion collisions at RHIC. Instead of weakly coupled gas of quasiparticles, it is rather a liquid-like matter with multiple bound states. In this paper we discuss how one can test these ideas experimentally,

Rajamani Narayanan

Continuum reduction in large N QCD enables one to extract physical quantities in the $N\to\infty$ limit of QCD by working in small physics volumes. The computation of chiral condensate is an example of such a calculation.

F. Di Renzo, L. Scorzato

We compute the so called residual mass in Lattice Heavy Quark Effective Theory to alpha^3 order in the n_f=2 (unquenched) case. The control of this additive mass renormalization is crucial for the determination of the heavy quark mass from lattice simulations. We discuss the impact on an unquenched determination of the b-quark mass.

F. Di Renzo, A. Mantovi, V. Miccio, Y. Schroder

We report on the perturbative computation of the 3d lattice Yang-Mills free energy to four loops by means of Numerical Stochastic Perturbation Theory. The known first and second orders have been correctly reproduced; the third and fourth order coefficients are new results and the known logarithmic IR divergence in the fourth order has been correctly identifi

F. Di Renzo, A. Mantovi, V. Miccio, L. Scorzato

Renormalization constants can be computed by means of Numerical Stochastic Perturbation Theory to two/three loops in lattice perturbation theory, both in the quenched approximation and in the full (unquenched) theory. As a case of study we report on the computation of renormalization constants of the propagator for Wilson fermions. We present our unquenched

Biagio Lucini, Philippe de Forcrand, Michele Vettorazzo

We propose a new algorithm to compute the order-order interface tension in SU(N) lattice gauge theories. The algorithm is trivially generalizable to a variety of models, e.g., spin models. In the case N=3, via the perfect wetting hypothesis, we can estimate the order-disorder interface tension. In the case N=4, we study the ratio of dual k-tensions and find

H. W. Zhao

Based on a data sample of an integrated luminosity of 57.4 fb-1 at the Upsilon(4S) resonance taken with the BaBar detector using the SLAC PEP-II asymmetric-energy $B$-Factory, hadronic decays of B meson with the final states D(*) and three pions are studied. The study is performed by fully reconstructing the exclusive decays of B->D(*)a_{1}(1260) and the non

P. Azzurri

In five years of operation (1996-2000) the four LEP2 experiments collected roughly 3 fb-1 of data from e+e- collisions at centre-of-mass energies between 161 and 207 GeV, yielding a total of about 40000 W-pair events. The analysis of the LEP2 W-pair production rates and kinematics has allowed fundamental new measurements of the electroweak model to be perfor

R. F. O'Connell

The recent discovery of a double-pulsar PSR J0737-3039A/B provides an opportunity of unequivocally observing, for the first time, spin effects in general relativity. Existing efforts involve detection of the precession of the spinning body itself. However, for a close binary system, spin effects on the orbit may also be discernable. Not only do they add to t

Alan Coley, Sigbjorn Hervik

We use a dynamical systems approach to analyse the tilting spatially homogeneous Bianchi models of solvable type (e.g., types VI$_h$ and VII$_h$) with a perfect fluid and a linear barotropic $γ$-law equation of state. In particular, we study the late-time behaviour of tilted Bianchi models, with an emphasis on the existence of equilibrium points and their st

M. C. B. Abdalla, A. A. Bytsenko, M. E. X. Guimaraes

Chiral cosmic strings are naturally produced at the end of D-term inflation and they present very interesting cosmological consequences. In this work, we investigate the formation and evolution of wakes by a chiral string. We show that, for cold dark matter, the mechanism of forming wakes by a chiral string is similar to the mechanism by an ordinary string.

Ashok Chatterjee, Parthasarathi Majumdar

The effects of thermal fluctuations of the mass (horizon area) and electric charge, on the entropy of non-rotating charged {\it macroscopic} black holes, are analyzed using a grand canonical ensemble. Restricting to Gaussian fluctuations around equilibrium, and assuming a power law type of relation between the black hole mass, charge and horizon area, charac

J. Hennig, G. Neugebauer

Dust configurations are the simplest models for astrophysical objects. Here we examine the gravitational collapse of an infinite cylinder of dust and give an analytic interior solution. Surprisingly, starting with a cylindrically symmetric ansatz one arrives at a 3-space with constant curvature, i.e. the resulting metric describes a piece of the Friedman int

S. Roch, P. Marcotte, G. Savard

We consider the problem of maximizing the revenue raised from tolls set on the arcs of a transportation network, under the constraint that users are assigned to toll-compatible shortest paths. We first prove that this problem is strongly NP-hard. We then provide a polynomial time algorithm with a worst-case precision guarantee of ${1/2}\log_2 m_T+1$, where $

Michael M. Tung

We give a brief introduction to FORM, a symbolic programming language for massive batch operations, designed by J.A.M. Vermaseren. In particular, we stress various methods to efficiently use FORM under the UNIX operating system. Several scripts and examples are given, and suggestions on how to use the vim editor as development platform.

S. Y. Savrasov

A computer program LMTART for electronic structure calculations using full potential linear muffin-tin orbital method is described

S. Y. Savrasov, A. Toropova, M. I. Katsnelson, A. I. Lichtenstein

We review basic computational techniques for simulations of various magnetic properties of solids. Several applications to compute magnetic anisotropy energy, spin wave spectra, magnetic susceptibilities and temperature dependent magnetisations for a number of real systems are presented for illustrative purposes.

R. Moussa, S. Foteinopoulou, Lei Zhang, G. Tuttle

We experimentally and theoretically studied a new left-handed (LH) structure based on a photonic crystal (PC) with a negative refractive index. The structure consists of triangular array of rectangular dielectric bars with dielectric constant 9.61. Experimental and theoretical results demonstrate the negative refraction and the superlensing phenomena in the

Michael T. Gastner, M. E. J. Newman

We study spatial networks that are designed to distribute or collect a commodity, such as gas pipelines or train tracks. We focus on the cost of a network, as represented by the total length of all its edges, and its efficiency in terms of the directness of routes from point to point. Using data for several real-world examples, we find that distribution netw

J. W. Clark, V. A. Khodel, M. V. Zverev

Thermodynamic characteristics of Fermi systems are investigated in the vicinity of a phase transition where the effective mass diverges and the single-particle spectrum becomes flat. It is demonstrated that at extremely low temperatures $T$, the flattening of the spectrum is reflected in non-Fermi-liquid behavior of the inverse susceptibility $χ^{-1}(T) \sim

J. Tao, D. Niebieskikwiat, M. B. Salamon, J. M. Zuo

We report the coexistence of lamellar charge-ordered (CO) and charge-disordered (CD) domains, and their dynamical behavior, in La0.23Ca0.77MnO3. Using high resolution transmission electron microscopy (TEM), we show that below Tcd~170K a CD-monoclinic phase forms within the established CO-orthorhombic matrix. The CD phase has a sheet-like morphology, perpendi

E. La Nave, F. Sciortino

We analyze differences in dynamics and in properties of the sampled potential energy landscape between different equilibrium trajectories, for a system of rigid water molecules interacting with a two body potential. On entering in the supercooled region, differences between different realizations enhance and survive even when particles have diffused several

Vladislav Popkov, Gunter M. Schuetz

We consider a driven diffusive system with two types of particles, A and B, coupled at the ends to reservoirs with fixed particle densities. To define stochastic dynamics that correspond to boundary reservoirs we introduce projection measures. The stationary state is shown to be approached dynamically through an infinite reflection of shocks from the boundar

Mehmet Dílaver, Semra Gündüç, Meral Aydın, Yiğit Gündüç

In this work we have calculated the dynamic critical exponent $z$ for 2-, 3- and 4-dimensional Ising models using the Wolff's algorithm through dynamic finite size scaling. We have studied time evolution of the average cluster size, the magnetization and higher moments of the magnetization. It is observed that dynamic scaling is independent of the algori

Eric Akkermans, Sankalpa Ghosh, Amos Schtalheim

The de Gennes free energy functional of an infinite smectic-A liquid crystal at the dual point is shown to be topological and to depend only on the number of screw dislocations and the anisotropy. This result generalizes the existence of a Bogomol'nyi bound to an anisotropic system. The role of the boundary of a finite mesoscopic smectic is to provide a

Andres Greco, Jaime Merino, Adriana Foussats, Ross H. McKenzie

The effect of antiferromagnetic spin fluctuations on two-dimensional quarter-filled systems is studied theoretically. An effective $t-J'-V$ model on a square lattice which accounts for checkerboard charge fluctuations and next-nearest-neighbors antiferromagnetic spin fluctuations is considered. From calculations based on large-N theory on this model it i

E. Arrigoni, E. Fradkin, S. A. Kivelson

Switching on interchain coupling in a system of one-dimensional strongly interacting chains often leads to an ordered state. Quite generally, there is a competition between an insulating charge-density-wave and a superconducting state. In the case of repulsive interactions, charge-density wave usually wins over superconductivity. Here, we show that a suitabl

K. W. Schmid, T. Dahm, J. Margueron, H. Müther

We apply a variational method devised for the nuclear many--body problem to the 1-dimensional Hubbard--model with nearest neighbor hopping and periodic boundary conditions. The test wave function consist for each state out of a single Hartree--Fock determinant mixing all the sites (or momenta) as well as the spin--projections of the electrons. Total spin and

Valentin V. Sokolov

Effect of a complicated many-body environment is analyzed on the chaotic motion of a quantum particle in a mesoscopic ballistic structure. The dephasing and absorption phenomena are treated on the same footing in the framework of a schematic microscopic model. The single-particle doorway resonance states excited in the structure via an external channel are d

Takahiko Miyakawa, Pierre Meystre

We consider the photoassociation of a low-density gas of quantum-degenerate trapped fermionic atoms into bosonic molecules in a spherically symmetric harmonic potential. For a dilute system and the photoassociation coupling energy small compared to the level separation of the trap, only those fermions in the single shell with Fermi energy are coupled to the

Satoshi Iikubo, Masafumi Ito, Akito Kobayashi, Masatoshi Sato

Magnetic excitation spectra c"(q,w) of YBa2Cu3Oy and La214 systems have been studied. For La1.88Sr0.12CuO4, c"(q,w) have been measured up to ~30 meV and existing data have been analyzed up to the energy w~150 meV by using the phenomenological expression of the generalized magnetic susceptibility c(q,w)=c0(q,w)/{1+J(q)c0(q,w)}, where c0(q,w) is the su

M. Theis, G. Thalhammer, K. Winkler, M. Hellwig

We demonstrate optical tuning of the scattering length in a Bose-Einstein condensate as predicted by Fedichev {\em et al.} [Phys. Rev. Lett. {\bf 77}, 2913 (1996)]. In our experiment atoms in a $^{87}$Rb condensate are exposed to laser light which is tuned close to the transition frequency to an excited molecular state. By controlling the power and detuning

G. Chaboussant, A. Sieber, S. Ochsenbein, H. -U. Guedel

We perform inelastic neutron scattering measurements on the molecular nanomagnet Mn_12-acetate to measure the excitation spectrum up to 45meV (500K). We isolate magnetic excitations in two groups at 5-6.5meV (60-75K) and 8-10.5meV (95-120K), with higher levels appearing only at 27meV (310K) and 31meV (360K). From a detailed characterization of the transition

D. S. Petrov

We consider a three-boson system with resonant binary interactions and show that three-body observables depend only on the resonance width and the scattering length. The effect of narrow resonances is qualitatively different from that of wide resonances revealing novel physics of three-body collisions. We calculate the rate of three-body recombination to a w

J. Mittaz, R. Lieu, R. Cen, M. Bonamente

The confirmation of the cluster soft excess (CSE) by XMM-Newton has rekindled interest as to its origin. The recent detections of CSE emission at large cluster radii together with reports of OVII line emission associated with the CSE has led many authors to conjecture that the CSE is, in fact, a signature of the warm-hot intergalactic medium (WHIM). In this

Christopher W. Mauche, Peter J. Wheatley, Knox S. Long, John C. Raymond

Chandra HETG spectra of the prototypical dwarf novae SS Cyg and U Gem in quiescence and outburst are presented and discussed. When SS Cyg goes into outburst, it becomes dimmer in hard X-rays and displays a dramatic shift in its relative line strengths, whereas when U Gem goes into outburst, it becomes brighter in hard X-rays and displays only a minor shift i

E. Baron, Peter Nugent, David Branch, Peter H. Hauschildt

We briefly describe the current version of the PHOENIX code. We then present some results on the modeling of Type II supernovae and show that fits to observations can be obtained, when account is taken for spherically symmetric, line-blanketed, expanding atmospheres. We describe the SEAM method of obtaining distances to supernovae and briefly discuss its fut

Patrick A. Young, David Arnett

We examine contributions of second order physical processes to results of stellar evolution calculations amenable to direct observational testing. In the first paper in the series (Young et al. 2001) we established baseline results using only physics which are common to modern stellar evolution codes. In the current paper we establish how much of the discrep

R. R. White, J. Wren, H. Davis, M. Galassi

The internet has brought about great change in the astronomical community, but this interconnectivity is just starting to be exploited for use in instrumentation. Utilizing the internet for communicating between distributed astronomical systems is still in its infancy, but it already shows great potential. Here we present an example of a distributed network

E. Rasia, P. Mazzotta, S. Borgani, L. Moscardini

The thermal properties of hydrodynamical simulations of galaxy clusters are usually compared to observations by relying on the emission-weighted temperature T_ew, instead of on the spectroscopic X-ray temperature T_spec, which is obtained by actual observational data. In a recent paper Mazzotta et al. show that, if the cluster is thermally complex, T_ew fail

Robert J. Nemiroff, Bijunath Patla

The observed dark energy in the universe might give particles inertial mass. We investigate one realization of this idea, that the dark energy field might be a decayed scalar component of a supermultiplet field in the early universe that creates inertial mass through spontaneous symmetry breaking, e.g. a Higgs field. To investigate this possibility, the cosm

S. V. Zharikov, G. H. Tovmassian, V. Neustroev, R. Michel

We present simultaneous spectral and photometric observations of SDSS J123813.73-033933.0. From Ha radial velocity measurements we determined the orbital period of the system to be 0.05592+/-0.00002 days (80.53 min). The spectrum shows double Balmer emission lines flanked by strong, broad absorption, indicating a dominant contribution from the white dwarf. T

Jon. P. Fulbright, R. Michael Rich, Sandra Castro

We report the abundance analysis of new high S/N spectra of the most metal-poor ([Fe/H] $= -2.95$) star presently known to be a member of a dwarf galaxy, the Draco dSph red giant, D119. No absorption lines for elements heavier than Ni are detected in two Keck HIRES spectra covering the $λλ$ 3850--6655 Å wavelength range, phenomenon not previously noted in an

E. Habart, L. Testi, A. Natta, M. Carbillet

We present adaptive optics high angular resolution ($\sim0\farcs$1) spectroscopic observations in the 3 $μ$m region of the Herbig Ae/Be star HD 97048. For the first time, we spatially resolve the emission in the diamond features at 3.43 and 3.53 $μ$m and in the adjacent continuum. Using both the intensity profiles along the slit and reconstructed two-dimensi

S. Anton, I. W. A. Browne

We analyse a group of radio sources, a subset of the 200 mJy sample, all of which have core-jet radio structures measured with VLBI and have flat spectra stretching from the radio to the millimetre/sub-millimetre band. Thus the objects have most of the properties expected of blazars. However, they display varied optical properties ranging from ``Seyfert-like

P. Mohr, T. Shizuma, H. Ueda, S. Goko

The neutron capture cross section of the unstable s-process branching nucleus 185W has been derived from experimental data of the inverse 186W(g,n)185W photodisintegration taken with monochromatic photon beams from laser Compton scattering. The result of sigma = 553 +- 60 mb at kT = 30 keV leads to a relatively high effective neutron density in the classical

LOPES Collaboration, A. Horneffer

Radio pulses emitted in the atmosphere during the air shower development of high-energy primary cosmic rays were measured during the late 1960ies in the frequency range from 2 MHz to 520 MHz. Mainly due to difficulties with radio interference these measurements ceased in the late 1970ies. LOFAR (Low Frequency Array) is a new digital radio interferometer unde

James Binney

I review evidence that galaxies form from gas that falls into potential wells cold, rather than from virialized gas, and that formation stops once an atmosphere of trapped virialized gas has accumulated. Disk galaxies do not have such atmospheres, so their formation is ongoing. During galaxy formation feedback is an efficient process, and the nuclear regions

Andrew H. Jaffe

We discuss the ability of the SKA to observe QSO proper motions induced by long-wavelength gravitational radiation. We find that the SKA, configured for VLBI with multiple beams at high frequency (8 GHz), is sensitive to a dimensionless characteristic strain of roughly $10^{-13}$, comparable to (and with very different errors than) other methods in the 1/yr

D. Nogami, B. Monard, A. Retter, A. Liu

We conducted a time-resolved photometric campaign of the helium dwarf nova, 2003aw in 2004 May--June. 2003aw stayed at 14.7--15.7 mag for the first several days during this campaign, which is the plateau phase of this superoutburst. This variable then rapidly decayed to $\sim$18.0 mag, still brighter by about 2 mag than its quiescence magnitude, and maintain

Erhard Scholz

A conservative extension of general relativity by integrable Weyl geometry is formulated, and a new class of cosmological models ({\em Weyl universes}) is introduced and studied. A short discussion of how these new models behave in the light of observational evidence follows. It turns out that the subclass of Weyl universes with positive ex-ante curvature of

J. Vennik, U. Hopp

We have carried out surface photometry of four bright known members and a number of new possible LSB companions of the IC 65 (LGG 16) group of galaxies. The purpose of the present study is twofold: (a) a search for new LSB dwarf members and measuring of their global photometric characteristics, and (b) a search for possible effects of mutual interactions on

P. Ciarcelluti

In the mirror world hypothesis the mirror baryonic component emerges as a possible dark matter candidate. Here we study the behaviour of the mirror dark matter and the differences from the more familiar CDM candidate for structure formation, cosmic microwave background and large scale structure. We show mirror models for CMB and LSS power spectra and compare

R. F. Minchin, M. J. Disney, Q. A. Parker, P. J. Boyce

We have placed limits on the cosmological significance of gas-rich low surface-brightness (LSB) galaxies as a proportion of the total population of gas-rich galaxies by carrying out a very deep survey (HIDEEP) for neutral hydrogen (HI) with the Parkes multibeam system. Such a survey avoids the surface-brightness selection effects that limit the usefulness of

Myriam Gitti, Sabine Schindler

We report on an XMM-Newton observation of RX J1347.5-1145 (z=0.451), the most luminous X-ray cluster of galaxies currently known, with a luminosity L_X = 6.0 \pm 0.1 \times 10^45 erg/s in the [2-10] keV energy band. We present the first temperature map of this cluster, which shows a complex structure. It identifies the cool core and a hot region at radii 50-

Eric Emsellem

I discuss evidences for bar-driven gas fueling in the central regions of galaxies, focusing on scales down to about 10 pc. I thus mention the building of inner disks, and the link with resonances, as well as the corresponding kinematic signatures such as sigma-drops and counter-rotating nuclear disks as probed via integral-field spectroscopy.

G. Giovannini, G. B. Taylor, L. Feretti, W. D. Cotton

We present a new, complete, sample of 95 radio sources selected from the B2 and 3CR catalogues, with z < 0.1. Since no selection effect on the core radio power, jet velocity, or source orientation is present, this sample is well suited for statistical studies. In this first paper we present the observational status of all sources on the parsec (mas) and kilo

Eric Emsellem

I briefly mention a few possible applications of very high spectral resolution spectroscopy with CRIRES to the study of nearby galaxies. This includes the fields of AGN, dynamically cold systems, super stellar and emission line clusters, and a more speculative program on the measurement of gravitational redshifts.

A. M. Fridman, V. L. Afanasiev, S. N. Dodonov, O. V. Khoruzhii

We analyzed ionized gas motion and disk orientation parameters for 15 spiral galaxies. Their velocity fields were measured with the H-alpha emission line by using the Fabry-Perot interferometer at the 6m telescope of SAO RAS. Special attention is paid to the problem of estimating the position angle of the major axis (PA_0) and the inclination (i) of a disk,

D. Pfenniger, Y. Revaz

The Baryonic Tully-Fisher relation (BTF) can be substantially improved when considering that the galactic baryonic mass is likely to consist not only from the detected baryons, stars and gas, but also from a dark baryonic component proportional to the HI gas. The BTF relation is optimally improved when the HI mass is multiplied by a factor of about 3, but la

V. Canoa, N. Armesto, C. Pajares, R. A. Vazquez

The mechanism of hadronic interactions at very high energies is still unclear. Available accelerator data constrain weakly the forward rapidity region which determines the development of atmospheric showers. This ignorance is one of the main sources of uncertainty in the determination of the energy and composition of the primary in hadron-induced atmospheric

P. Mazzotta, E. Rasia, L. Moscardini, G. Tormen

Theoretical studies of the physical processes in clusters of galaxies are mainly based on the results of numerical simulations, which in turn are often directly compared to X-ray observations. Although trivial in principle, these comparisons are not always simple. We show that the projected spectroscopic temperature of clusters obtained from X-ray observatio

B. Stelzer

I report on the X-ray detection of Gl569Bab. During a 25ksec Chandra observation the binary brown dwarf is for the first time spatially separated in X-rays from the flare star primary Gl569A. Companionship to Gl569A constrains the age of the brown dwarf pair to ~300-800 Myr. The observation presented here is only the second X-ray detection of an evolved brow

E. Middelberg, A. L. Roy, R. C. Walker, H. Falcke

We use a new phase-calibration strategy to calibrate the phase of 86 GHz VLBI observations of the FR I radio galaxy NGC 4261. Instead of switching between a calibrator source and the target source, the target was observed while rapidly switching between the target frequency and a lower reference frequency. Self-calibration at the reference frequency yielded

Hideki Asada, Toshio Akasaka, Masumi Kasai

It is believed that some numerical technique must be employed for the determination of the system parameters of a visual binary or a star with a planet because the relevant equations are not only highly nonlinear but also transcendental owing to the Kepler&#39;s equation. Such a common sense, however, is not true; we discover an analytic inversion formula, i

Hideki Asada

We study the effect of the core radius of an isothermal ellipsoidal gravitational lens on the caustics and the critical curves. We derive an analytic expression of the caustics for an isothermal ellipsoidal gravitational lens via a sixth-order algebraic equation. Since the expression is too long, by using another method we obtain a parametric representation

P. P. Fiziev

We describe a novel class of geometrical models of relativistic stars. Our approach to the static spherically symmetric solutions of Einstein equations is based on a careful physical analysis of radial gauge conditions. It brings us to a two parameter family of relativistic stars without stiff functional dependence between the stelar radius and stelar mass.

Marc Lachieze-Rey

We show that the multipole vector decomposition, recently introduced by Copi et al., is a consequence of Sylvester&#39;s theorem, and corresponds to the Maxwell&#39;s representation. Analyzing it in terms of harmonic polynomials, we show that this decomposition results in fact from the application of the harmonic projection operator and its inverse. We deriv

A. Belletoile, D. Ardouin, D. Charrier, Richard Dallier

Data acquisition and analysis for the CODALEMA experiment, in operation for more than one year, has provided improved knowledge of the characteristics of this new device. At the same time, an important effort has been made to develop processing techniques for extracting transient signals from data containing interference.

R. X. Xu

Both rotation- and accretion-powered low-mass bare strange stars are studied, the astrophysical appearances of which are especially focused. It is suggested that low-mass bare strange stars, with weaker ferromagnetic fields than that of normal pulsars, could result from accretion-induced collapses (AIC) of white dwarfs. According to its peculiar timing behav

Matthieu Wyart, Sidney R. Nagel, T. A. Witten

Glasses have a large excess of low-frequency vibrational modes in comparison with crystalline solids. We show that such a feature is a necessary consequence of the geometry generic to weakly connected solids. In particular, we analyze the density of states of a recently simulated system, comprised of weakly compressed spheres at zero temperature. We account

A. M. Lisewski, O. Lichtarge

We present a statistical approach to protein structure by introducing a representation of protein folds based on simple observables defined as frequencies of oriented cycles in contact graphs. Motivated by the idea that these cycles may form a code of the entire protein structure we investigate its Shannon entropy. The latter shows a characteristic transitor

Christopher King, Michael Nathanson, Mary Beth Ruskai

Multiplicativity of certain maximal p -> q norms of a tensor product of linear maps on matrix algebras is proved in situations in which the condition of complete positivity (CP) is either augmented by, or replaced by, the requirement that the entries of a matrix representative of the map are non-negative (EP). In particular, for integer t, multiplicativity h

P. Markos, C. M. Soukoulis

Transmission of the scalar field through the random medium, represented by the system of randomly distributed dielectric cylinders is calculated numerically. System is mapped to the problem of electronic transport in disordered two-dimensional systems. Universality of the statistical distribution of transmission parameters is analyzed in the metallic and in

Takuya Okuda

We derive new crystal melting models from Chern-Simons theory on the three-sphere. Via large N duality, these models compute amplitudes for A-model on the resolved conifold. The crystal is bounded by two walls whose distance corresponds to the Kahler modulus of the geometry. An interesting phenomenon is found where the Kahler modulus is shifted by the presen

M. Gunaydin, O. Pavlyk

We study the minimal unitary representations of noncompact exceptional groups that arise as U-duality groups in extended supergravity theories. First we give the unitary realizations of the exceptional group E_{8(-24)} in SU*(8) as well as SU(6,2) covariant bases. E_{8(-24)} has E_7 X SU(2) as its maximal compact subgroup and is the U-duality group of the ex

P. G. Silvestrov, I. V. Ponomarev

We consider a mechanism for area preserving Hamiltonian systems which leads to the enhanced probability, $P(λ, t)$, to find small values of the finite time Lyapunov exponent, $λ$. In our investigation of chaotic dynamical systems we go beyond the linearized stability analysis of nearby divergent trajectories and consider folding of the phase space in the cou

G. Kaniadakis, M. Lissia, A. M. Scarfone

A consistent generalization of statistical mechanics is obtained by applying the maximum entropy principle to a trace-form entropy and by requiring that physically motivated mathematical properties are preserved. The emerging differential-functional equation yields a two-parameter class of generalized logarithms, from which entropies and power-law distributi

V. A. Brazhnyi, V. V. Konotop

Mean-filed dynamics of a Bose-Einstein condensate (BEC) loaded in an optical lattice (OL), confined by a parabolic potentials, and subjected to change of a scattering length by means of the Feshbach resonance (FR), is considered. The system is described by the Gross-Pitaevskii (GP) equation with varying nonlinearity, which in a number of cases can be reduced

Tomoyuki Takenawa

We propose an $n$-dimensional analogue of elliptic difference Painlevé equation. Some Weyl group acts on a family of rational varieties obtained by successive blow-ups at $m$ points in $\mpp^n(\mc)$, and in many cases they include the affine Weyl groups with symmetric Cartan matrices as subgroups. It is shown that the dynamical systems obtained by translatio

Feng Huang, Rong-Guang Xu, Bo-Qiang Ma

We take into account the sigma meson cloud effect in the meson cloud model to calculate the distributions of light flavor sea quarks in the proton. Our calculation gives a better description of the data for $\bar{d}(x)/\bar{u}(x)$. We also provide a picture that the probability of finding a physical proton in a Fock state $|Nω> $ is reasonable small with a s

Adam R. Altman, Kahraman G. Köprülü, Eric Corndorf, Prem Kumar

Through scanned coincidence counting, we probe the quantum image produced by parametric down conversion with a pump beam carrying orbital angular momentum. Nonlocal spatial correlations are manifested through splitting of the coincidence spot into two.

Michael R. Geller, Andrew N. Cleland

We describe the design for a scalable, solid-state quantum-information-processing architecture based on the integration of GHz-frequency nanomechanical resonators with Josephson tunnel junctions, which has the potential for demonstrating a variety of single- and multi-qubit operations critical to quantum computation. The computational qubits are eigenstates

G. W. Ford, R. F. O&#39;Connell

While agreeing with our exact expression for the time dependence of the motion of a free particle in an initial superposition state, corresponding to two identical Gaussians separated by a distance $d$, at temperature $T$, Gobert et al., in the preceding Comment [Phys. Rev. A xxx], dispute our conclusions on decoherence time scales. However, the parameters t