August 2004 arXiv papers — page 2

M. Anselmino, M. Boglione, U. D'Alesio, E. Leader

We consider a general formalism to compute inclusive polarised and unpolarised cross sections within pQCD and the factorisation scheme, taking into account parton intrinsic motion in distribution and fragmentation functions, as well as in the elementary dynamics. Surprisingly, the intrinsic partonic motion, with all the correct azimuthal angular dependences,

Cristina Manuel

Transport coefficients of dense quark matter are needed to study properties of compact stars. They can tell us about the cooling, vibrational and rotational properties of the star. We report below a computation of the shear viscosity in the CFL phase at low temperature T. CFL quark matter behaves as a superfluid, and at low T its transport properties are dom

Amruta Mishra, Hiranmaya Mishra

We investigate the chiral symmetry breaking and color superconductivity in color and electric charge neutral quark matter including strange quarks (2SC+s quark matter) in a Nambu-Jona-Lasinio model using a variational method. The methodology involves an explicit construction of a variational ground state and minimisation of the thermodynamic potential. Simul

G. P. Vacca

A review of some theoretical aspects of small x QCD physics is given, with a particular emphasis to the relation between the BFKL and the colour dipole approaches. The nonlinear evolution equations one may construct, as a better approximation beyond the linear analysis, are discussed together with their relation to a possible saturation regime.

Peter Wienemann

Provided SUSY is realized in Nature, future colliders like the Large Hadron Collider (LHC) and a future e+e- linear collider (LC) will provide a wealth of data on SUSY phenomena. One important task will be to extract the Lagrangian parameters at the electroweak scale from the numerous measured observables and to extrapolate them to a high scale to check whet

Fredrik Borg

A kaon decaying into three pions is an example of a weak process. However, since the quarks are confined into mesons, the strong interaction also plays an important part. The reaction is a low-energy one, meaning that it takes place in the non-perturbative region of QCD. In that region perturbative QCD doesn't give you any answers and other methods have

D. Sexty, A. Patkos

Real time field excitations in the broken symmetry phase of the classical abelian Gauge+Higgs model are studied numerically in the unitary gauge, for systems starting from the unstable maximum of the Higgs potential.

Guy D. Moore

I give a physical explanation of what shear viscosity is, and what physics determines its value. Then I explain why determining the shear viscosity of the Quark-Gluon Plasma is interesting. I outline the leading-order calculation of the QGP shear viscosity (and baryon number diffusion constant), explaining why the quite complicated physics of parton splittin

M. Strikman, C. Weiss

We summarize what is known about the transverse spatial distribution of gluons in the nucleon and its x-dependence from exclusive J/psi photo/electroproduction in e-p fixed-target and collider experiments (HERA H1 and ZEUS). This information can be used to predict the impact parameter dependence of the cross section for certain hard QCD processes (dijet prod

Thomas Becher, Richard J. Hill

One-loop matching corrections are calculated for Soft-Collinear Effective Theory (SCET) operators relevant to the analysis of heavy-to-light meson form factors at large recoil. The numerical impact of radiative corrections on form factor predictions is assessed. Evanescent operators in the effective theory are studied and it is shown that even in problems of

B. Bunk, M. Della Morte, K. Jansen, F. Knechtli

We address the locality problem arising in simulations, which take the square root of the staggered fermion determinant as a Boltzmann weight to reduce the number of dynamical quark tastes from four to two. We study analytically and numerically the square root of the staggered fermion operator as a candidate to define a two taste theory from first principles

C. Schmidt

After giving an overview of recently invented methods for simulating lattice QCD at small mu/T, we discuss some results for bulk thermodynamic quantities of QCD matter coming from those methods. We focus on the transition line and the critical endpoint in the QCD phase diagram.

S. Ejiri, C. R. Allton, M. Doering, S. J. Hands

We discuss the equation of state (EoS) for two flavor QCD at non-zero temperature and density. Derivatives of $\ln Z$ with respect to quark chemical potential $μ_q$ are calculated up to sixth order. From this Taylor series, the pressure, quark number density and associated susceptibilities are estimated as functions of temperature and $μ_q$. It is found that

M. Martinez

In this contribution, a review of some of the most important QCD jet preliminary results from both CDF and D0 experiments in Run II is presented, together with future prospects as the integrated luminosity increases.

Andy Hocker

The CDF and D0 collaborations at Fermilab's Tevatron p-pbar collider have in place an extensive program to measure fundamental properties of the top quark. Recent results from Run I (sqrt-s = 1.8 TeV) and Run II (sqrt-s = 1.96 TeV) on the top quark's production, mass, and decays are presented here. All results are consistent within their uncertaintie

H1 Collaboration

Inclusive production cross sections are measured in deep inelastic scattering at HERA for meson states composed of a charm quark and a light antiquark or the charge conjugate. The measurements cover the kinematic region of photon virtuality 2 < Q^2 < 100 GeV^2, inelasticity 0.05 < y < 0.7, D meson transverse momenta p_t(D) > 2.5 GeV and pseudorapidity |eta(D

Luis O. Pimentel, Cesar Mora

We consider noncommutative quantum cosmology in the case of the low-energy string effective theory. Exacts solutions are found and compared with the commutative case.The Noncommutative quantum cosmology is considered in the case of the low-energy string effective theory. Exacts solutions are found and compared with the commutative case.

Michael J. W. Hall

The assumption that an ensemble of classical particles is subject to nonclassical momentum fluctuations, with the fluctuation uncertainty fully determined by the position uncertainty, has been shown to lead from the classical equations of motion to the Schroedinger equation. This &#39;exact uncertainty&#39; approach may be generalised to ensembles of gravita

Sebastian Bader, Pascal Hitzler, Steffen Hoelldobler

Intelligent systems based on first-order logic on the one hand, and on artificial neural networks (also called connectionist systems) on the other, differ substantially. It would be very desirable to combine the robust neural networking machinery with symbolic knowledge representation and reasoning paradigms like logic programming in such a way that the stre

Jennie C. Hansen, Eric Schmutz, Li Sheng

Li and Wu proposed Rule 2, a localized approximation algorithm that attempts to find a small connected dominating set in a graph. Here we study the asymptotic performance of Rule 2 on random unit disk graphs formed from n random points in an s_n by s_n square region of the plane. If s_n is below the threshold for connectivity, then Rule 2 produces a dominati

Jennie C. Hansen, Eric Schmutz

Rule k is a localized approximation algorithm that finds a small connected dominating set in a graph. We estimate the expected size of the Rule k dominating set for the model of random unit disk graphs constructed from n random points in an s_n by s_n square region of the plane.

S. H. Mennema, J. H. T. Ransley, G. Burnell, J. L. MacManus-Driscoll

By lithographically fabricating an optimised Wheatstone bridge geometry, we have been able to make accurate measurements of the resistance of grain boundaries in Y1-xCaxBa2Cu3O7-d between the superconducting transition temperature, Tc, and room temperature. Below Tc the normal state properties were assessed by applying sufficiently high currents. The behavio

Arlette R. C. Baljon, Joris Billen, Rajesh Khare

We present an analysis of heterogeneous dynamics in molecular dynamics simulations of a thin polymeric film, supported by an absorbing structured surface. Near the glass transition &#34;immobile&#34; domains occur throughout the film, yet the probability of their occurrence decreasing with larger distance from the surface. Still, enough immobile domains are

Yu-Jun Zhao, Alex Zunger

The need for spin-injectors having the same zincblende-type crystal structure as conventional semiconductor substrates has created significant interests in theoretical predictions of possible metastable ``half-metallic&#39;&#39; zincblende ferromagnets, which are normally more stable in other structure-types, e.g., NiAs. Such predictions were based in the pa

Normand Mousseau, G. T. Barkema

Many properties of disordered materials can be understood by looking at idealized structural models, in which the strain is as small as is possible in the absence of long-range order. For covalent amorphous semiconductors and glasses, such an idealized structural model, the continuous-random network, was introduced 70 years ago by Zachariasen. In this model,

Aaron Fleet, Darren Dale, Y. Suzuki, J. D. Brock

We grew SrTiO3 on SrTiO3 [001] by pulsed laser deposition, while observing x-ray diffraction at the (0 0 .5) position. The drop dI in the x-ray intensity following a laser pulse contains information about plume-surface interactions. Kinematic theory predicts dI/I = -4sigma(1-sigma), so that dI/I depends only on the amount of deposited material sigma. In cont

D. Cao, R. H. Heffner, F. Bridges, I. -K. Jeong

Extended X-ray Absorption Fine Structure (EXAFS) experiments have been carried out on PrRu$_4$P$_{12}$ and PrOs$_4$P$_{12}$ to study the metal-to-insulator (MI) phase transition in PrRu$_4$P$_{12}$. No Pr displacement was observed across the MI transition temperature from the EXAFS data. Instead, our EXAFS data clearly show that a Ru displacement is associat

M. D. Johannes, D. A. Papaconstantopoulos, D. J. Singh, M. J. Mehl

We perform an orthogonal basis tight binding fit to an LAPW calculation of paramagnetic Na$_x$CoO$_2$ for several dopings. The optimal position of the apical oxygen at each doping is resolved, revealing a non-trivial dependence of the band structure and Fermi surface on oxygen height. We find that the small e$_{g&#39;}$ hole pockets are preserved throughout

A. E. Allahverdyan, Th. M. Nieuwenhuizen

We study how Thomson&#39;s formulation of the second law: no work is extracted from an equilibrium ensemble by a cyclic process, emerges in the quantum situation through the averaging over fluctuations of work. The latter concept is carefully defined for an ensemble of quantum systems interacting with macroscopic sources of work. The approach is based on fir

M. D. Johannes, I. I. Mazin, D. J. Singh

We have calculated the optical spectra of Na$_{x}$CoO$_2$ for $x$=0.3, 0.5, and 0.7 within the LDA. We compare our results to available experimental data and show that the important features and trends are reproduced well, but there is a nearly uniform shift of peak positions and poor agreement in intensities. We show, through application of a simple model,

V. V. Kabanov, T. Mertelj, D. Mihailovic

We have derived the interaction between Jahn-Teller centers due to optical and acoustic phonons. Without Coulomb repulsion the model leads to a global phase separation at low temperature. At long distances Coulomb repulsion always dominates the short range attraction leading to phase separation on a short scale. On the basis of Monte-Carlo simulation of micr

Stephen Whitelam, Ludovic Berthier, Juan P. Garrahan

We derive a dynamic field theory for a kinetically constrained model, based on the Fredrickson--Andersen model, which we expect to describe the properties of an Arrhenius (strong) supercooled liquid at the coarse-grained level. We study this field theory using the renormalization group. For mesoscopic length and time scales, and for space dimension d \geq 2,

M. Bak

The paper examines part of the ground state diagram of the extended Hubbard model, with the on-site attraction U<0 and intersite repulsion W>0 in the presence of charge density waves, superconducting and $η$-superconducting order parameters. We show the possibility of the stabilization of the mixed state, with all three nonzero order parameters, in the model

Jürgen König, Yuval Gefen

We study the occupation of two electrostatically-coupled single-level quantum dots with spinless electrons as a function of gate voltage. While the total occupation of the double-dot system varies monotonically with gate voltage, we predict that the competition between tunneling and Coulomb interaction can give rise to a nonmonotonic filling of the individua

Hsiang-Hsuan Hung, Chang-De Gong

In this article, we study the one dimensional Heisenberg spin-1/2 alternating bond chain in which the nearest neighbor exchange couplings are ferromagnetic (FM) and antiferromagnetic (AF) alternatively. By using exact diagonalization and density matrix renormalization groups (DMRG) method, we discuss how the system approaches to the AF uniform spin-1 chain u

Thomas Bickel, Mabrouk Benhamou, Hamid Kaidi

Surface effects are generally prevailing in confined colloidal systems. Here we report on dispersed nanoparticles close to a fluid membrane. Exact results regarding the static organization are derived for a dilute solution of non-adhesive colloids. It is shown that thermal fluctuations of the membrane broaden the density profile, but on average colloids are

A. C. Hewson

In recent work we have shown that the Fermi liquid aspects of the strong coupling fixed point of the s-d and Anderson models can brought out more clearly by interpreting the fixed point as a renormalized Anderson model, characterized by a renormalized level $\tildeε_d$, resonance width, $\tildeΔ$, and interaction $\tilde U$, and a simple prescription for the

J. M. Pitarke, V. M. Silkin, E. V. Chulkov, P. M. Echenique

Since the concept of a surface collective excitation was first introduced by Ritchie, surface plasmons have played a significant role in a variety of areas of fundamental and applied research, from surface dynamics to surface-plasmon microscopy, surface-plasmon resonance technology, and a wide range of photonic applications. Here we review the basic concepts

M. Costeniuc, R. S. Ellis, H. Touchette, B. Turkington

Shortened abstract: Microcanonical equilibrium macrostates are characterized as the solutions of a constrained minimization problem, while canonical equilibrium macrostates are characterized as the solutions of a related, unconstrained minimization problem. In Ellis, Haven, and Turkington (J. Stat. Phys. 101, 999, 2000) the problem of ensemble equivalence wa

Ye. S. Avotina, A. Namiranian, Yu. A. Kolesnichenko

The influence of the interference of electron waves, which are scattered by single impurities and by a barrier on nonlinear conductance and shot noise of metallic microconstriction is studied theoretically. It is shown that the these characteristics are nonmonotonic functions on the applied bias.

Oscar Iglesias, Amilcar Labarta

We present the results of Monte Carlo simulations of the magnetic properties of individual spherical nanoparticles with the aim to explain the role played by surface anisotropy on their low temperature magnetization processes. Phase diagrams for the equilibrium configurations have been obtained, showing a change from quasi-uniform magnetization state to a st

Manabu Kiguchi, Ryotaro Arita, Genki Yoshikawa, Yoshiaki Tanida

We have shown, both experimentally and theoretically, that the metal-induced gap states (MIGS) can exist in epitaxially grown organic insulator/metal interfaces. The experiment is done for alkane/Cu(001) with an element-selective near edge x-ray absorption fine structure (NEXAFS), which exhibits a pre-peak indicative of MIGS. An {\it ab initio} electronic st

E. Anisimovas, A. Matulis, M. B. Tavernier, F. M. Peeters

We show that the critical magnetic fields at which a few-electron quantum dot undergoes transitions between successive values of its angular momentum (M), for large M values follow a very simple power-law dependence on the effective inter-electron interaction strength. We obtain this power law analytically from a quasi-classical treatment and demonstrate its

M. Bartenstein, A. Altmeyer, S. Riedl, R. Geursen

We employ radio-frequency spectroscopy on weakly bound $^6$Li$_2$ molecules to precisely determine the molecular binding energies and the energy splittings between molecular states for different magnetic fields. These measurements allow us to extract the interaction parameters of ultracold $^6$Li atoms based on a multi-channel quantum scattering model. We de

E. Anisimovas, A. Matulis, F. M. Peeters

Currents in a few-electron parabolic quantum dot placed into a perpendicular magnetic field are considered. We show that traditional ways of investigating the Wigner crystallization by studying the charge density correlation function can be supplemented by the examination of the density-current correlator. However, care must be exercised when constructing th

Hyun C. Lee, Han-Yong Choi

The infinite-$U$ Anderson-Holstein impurity model is studied with a focus on the interplay between the strong electron correlation and the weak electron-phonon interaction. The slave boson method has been employed in combination with the large degeneracy expansion (1/N) technique. The charge and spin susceptibilities and the phonon propagator are obtained in

Igor Khavkine, Hae-Young Kee, Kazumi Maki

In recent years, a number of nodal superconductors have been identified; d-wave superconductors in high T_c cuprates, CeCoIn$_5$, and κ-(ET)_2Cu(NCS)_2, 2D f-wave superconductor in Sr_2RuO_4 and hybrid s+g-wave superconductor in YNi_2B_2C. In this work we conduct a theoretical study of nodal superconductors in the presence of supercurrent. For simplicity, we

S. Andergassen, T. Enss, V. Meden, W. Metzner

We improve the recently developed functional renormalization group (fRG) for impurities and boundaries in Luttinger liquids by including renormalization of the two-particle interaction, in addition to renormalization of the impurity potential. Explicit flow-equations are derived for spinless lattice fermions with nearest neighbor interaction at zero temperat

B. D. Stosic, T. Stosic, I. P. Fittipaldi

While the Ising model on the Cayley tree has no spontaneous magnetization at nonzero temperatures in the thermodynamic limit, we show that finite systems of astronomical sizes remain magnetically ordered in a wide temperature range, if the symmetry is broken by fixing an arbitrary single (bulk or surface) spin. We compare the behavior of the finite size magn

Jong-Hak Woo, Meg Urry, Paulina Lira, Roeland van der Marel

We measured the stellar velocity dispersions of 15 active galactic nucleus (AGN) host galaxies at redshifts as high as $\sim 0.34$. Combining these with published velocity dispersion measurements from the literature, we study the Fundamental Plane of AGN host galaxies and its evolution. BL Lac hosts and radio galaxies seem to lie on the same Fundamental Plan

H. Socas-Navarro, J. Trujillo Bueno, E. Landi Degl&#39;Innocenti

We investigate the formation of polarization profiles induced by a magnetic field in the He I multiplet at 1083,0 nm . Our analysis considers the Zeeman splitting in the incomplete Paschen-Back regime. The effects turn out to be important and produce measurable signatures on the profiles, even for fields significantly weaker than the level-crossing field ($\

J. Trujillo Bueno, N. Shchukina, A. Asensio Ramos

Deciphering and understanding the small-scale magnetic activity of the quiet solar photosphere should help to solve many of the key problems of solar and stellar physics, such as the magnetic coupling to the outer atmosphere and the coronal heating. At present, we can see only ${\sim}1%$ of the complex magnetism of the quiet Sun, which highlights the need to

G. Walker, R. Atkins, D. Kieda

We have examined the directional cross-correlation of statistical `hot-spots&#39; between a Northern Sky TeV Gamma Ray Survey by the Milagro Observatory and a similar survey by the Tibet Array. We find the directions of these hot-spots are angularly uncorrelated between the two surveys for large angular separations (Delta theta > 4 degrees), but there appear

J. Hong, S. V. Vadawale, M. Zhang, E. C. Bellm

The proposed black-hole finder mission EXIST will consist of multiple wide-field hard X-ray coded-aperture telescopes. The high science goals set for the mission require innovations in telescope design. In particular, wide energy band coverage and fine angular resolution require relatively thick coded masks and thick detectors compared to their pixel size, w

E. Sabbi, F. R. Ferraro, A. Sills, R. T. Rood

We have used high resolution WFPC2-HST and wide field ground-based observations to construct a catalog of blue straggler stars (BSS) which spans the entire radial extent of the globular cluster NGC 6752. The BSS sample is the most extensive ever obtained for this cluster. Though NGC 6752 is a high density cluster with a large binary population, we found that

Hans J. Deeg, Roi Alonso, Juan A. Belmonte, Khalid Alsubai

An overview is given of the Permanent All Sky Survey (PASS) project. The primary goal of PASS is the detection of all transiting giant planets in the entire sky, complete for stellar systems of magnitudes ~ 5.5-10.5. Since the sample stars are fairly bright and relatively close, planets detected by PASS would be ideally suited for any follow-up study with gr

R. F. Gonzalez, E. M. de Gouveia Dal Pino, A. C. Raga, P. F. Velazquez

In this paper, we present two-dimensional gas dynamic simulations of the formation and evolution of the eta-Car bipolar outflows. Adopting the interacting nonspherical winds model, we have carried out high-resolution numerical simulations, which include explicitly computed time-dependent radiative cooling, for different possible scenarios of the colliding wi

J. M. Barr, J. C. Baker, M. N. Bremer, R. W. Hunstead

We have scanned the fields of six radio-loud quasars using the Taurus Tunable Filter to detect redshifted [OII] 3727 line-emitting galaxies at redshifts 0.8 < z < 1.3. Forty-seven new emission-line galaxy (ELG) candidates are found. This number corresponds to an average space density about 100 times that found locally and, at L([OII]) < 10^{42} erg s^{-1} cm

Barbara E. McArthur, Michael Endl, William D. Cochran, G. Fritz Benedict

We report the detection of the lowest mass extra-solar planet yet found around a Sun-like star - a planet with an \msini of only 14.21 $\pm$ 2.91 Earth masses in an extremely short period orbit (P=2.808 days) around $ρ^{1}$ Cancri, a planetary system which already has three known planets. Velocities taken from late 2003-2004 at McDonald Observatory with the

Michael S. Vogeley, Fiona Hoyle, Randall R. Rojas, David M. Goldberg

Wide-angle, moderately deep redshift surveys such as that conducted as part of the Sloan Digital Sky Survey (SDSS) allow study of the relationship between the structural elements of the large-scale distribution of galaxies -- including groups, cluster, superclusters, and voids -- and the dependence of galaxy formation and evolution on these enviroments. We p

N. L. Martin-Hernandez, D. Schaerer, M. Saugave

We present the N-band (8-13 micron) spectrum of the hidden compact radio super-star cluster in NGC 5253, C2, obtained with TIMMI2 on the ESO 3.6m telescope. The spectrum is characterised by a rising continuum due to warm dust, a silicate absorption and a strong [SIV] line at 10.5 micron. Weaker lines of [ArIII] at 9.0 micron and [NeII] at 12.8 micron are als

M. A. Perez-Torres, J. M. Marcaide, J. C. Guirado, E. Ros

We observed the thirteen extragalactic radio sources of the complete S5 polar cap sample at 15.4 GHz with the Very Long Baseline Array, on 27 July 1999 (1999.57) and 15 June 2000 (2000.46). We present the maps from those two epochs, along with maps obtained from observations of the 2 cm VLBA survey for some of the sources of the sample, making a total of 40

E. Pian, L. Foschini, V. Beckmann

We have performed observations of the blazar S5 0716+714 with INTEGRAL on 2-6 April 2004. In the first months of 2004, the source had increased steadily in optical brightness and had undergone two outbursts. During the latter, occurred in March, it reached the extreme level of R = 12.1 mag, which triggered our INTEGRAL program. The target has been detected w

C. W. Yip, A. J. Connolly, D. E. Vanden Berk, Z. Ma

We study 16,707 quasar spectra from the SDSS using the Karhunen-Loève (KL) transform (or Principal Component Analysis, PCA). The quasar eigenspectra of the full catalog reveal the following: 1st order - the mean spectrum; 2nd order - a host-galaxy component; 3rd order - the UV-optical continuum slope; 4th order - the correlations of Balmer emission lines. We

J. Horner, N. W. Evans, M. E. Bailey

Detailed orbit integrations of clones of five Centaurs -- namely, 1996 AR20, 2060 Chiron, 1995 SN55, 2000 FZ53 and 2002 FY36 -- for durations of 3 Myr are presented. One of our Centaur sample starts with perihelion initially under the control of Jupiter (1996 AR20), two start under the control of Saturn (Chiron and 1995 SN55) and one each starts under the co

P. Padovani

The Virtual Observatory (VO) will revolutionise the way we do Astronomy, by allowing easy access to all astronomical data and by making the handling and analysis of datasets at various locations across the globe much simpler and faster. I report here on the need for the VO and its status in Europe, including the first ever VO-based astronomical paper, and th

B. Nisini, S. Antoniucci, T. Giannini, D. Lorenzetti

Near IR spectra obtained with ISAAC at VLT, have been used to pose constraints on the evolutionary state and accretion properties of a sample of five embedded YSOs located in the R CrA core. This sample includes three Class I sources (HH100 IR, IRS2 and IRS5), and two sources with NIR excesses (IRS6 and IRS3). Absorption lines have been detected in the mediu

Masamune Oguri

We present theoretical and observational studies of strong gravitational lenses produced by clusters of galaxies. Our purpose is to test the Cold Dark Matter (CDM) model at small and highly non-linear scales where it has been claimed that the CDM model may confront several difficulties. We concentrate our attention on the statistics of strong gravitational l

G. Pietrzynski, W. Gieren, A. Udalski, F. Bresolin

We have obtained mosaic images of NGC 6822 in V and I bands on 77 nights. From these data, we have conducted an extensive search for Cepheid variables over the entire field of the galaxy, and we have found 116 such variables with periods ranging from 1.7 to 124 days. We used the long-period ($>$ 5.6 days) Cepheids to establish the period-luminosity relations

J. Vinko, R. M. Blake, K. Sarneczky, B. Csak

New optical photometric and spectroscopic data of the bright hypernova SN 2002ap are presented. The obtained BVRI light curves as well as the optical spectra agree well with other published data series. The distance has been inferred by applying the Expanding Photosphere Method for the data around maximum. The derived 6.7 Mpc is in good agreement with recent

Masakazu A. R. Kobayashi, Hideyuki Kamaya

The expected episodic or intermittent star formation histories (SFHs) of gas rich dwarf irregular galaxies (dIrrs) are the longstanding puzzles to understand their whole evolutional history. Solving this puzzle, we should grasp what physical mechanism causes the quiescent phase of star formation under the very gas rich condition after the first starburst pha

Richard Massey, Alexandre Refregier, David Bacon

The measurement of weak gravitational lensing is currently limited to a precision of ~10% by instabilities in galaxy shape measurement techniques and uncertainties in their calibration. The potential of large, on-going and future cosmic shear surveys will only be realised with the development of more accurate image analysis methods. We present a description

N. L. Homeier, J. Alves

The W49A star-forming region is embedded in a 10^6 solar mass molecular cloud, one of the most massive in our Galaxy. It has been long known as one of the most luminous radio HII regions, containing 30-40 compact and ultracompact HII regions and several hot cores. We have detected a previously unknown massive star cluster (Cluster 1) embedded in the W49 mole

Y. -Y. Zhang, H. Boehringer, Y. Mellier, G. Soucail

We present a detailed gravitational mass measurement based on the XMM-Newton imaging spectroscopy analysis of the lensing cluster of galaxies CL0024+17 at z=0.395. The emission appears approximately symmetric. However, on the scale of r~3.3&#39; some indication of elongation is visible in the northwest-southeast (NW-SE) direction from the hardness ratio map

M. H. van Kerkwijk, C. G. Bassa, B. A. Jacoby, P. G. Jonker

Optical observations of the companions of pulsars can help determine the properties of the binaries, as well as those of their components, and give clues to the preceding evolution. In this review, we first describe the different classes of binary pulsars, and present a table with a summary what is known about their optical counterparts. Next, we focus on th

Alexander Seidel, Hsiu-Hau Lin, Dung-Hai Lee

We study the effects of phonons in $N$-leg Hubbard ladders within the framework of a one-loop renormalization group. In particular, we explicitly demonstrate that the role of phonons changes {\em qualitatively} even in the simplest two-leg ladder, as compared to the single-chain system where phonons always dominate. Our numerical results suggest that in the

R. H. D. Townsend, S. P. Owocki

We present a semi-analytical approach for modeling circumstellar emission from rotating hot stars with a strong dipole magnetic field tilted at an arbitrary angle to the rotation axis. By assuming the rigid-field limit in which material driven (e.g., in a wind outflow) from the star is forced to remain in strict rigid-body co-rotation, we are able to solve f

Andres Meza, Julio F. Navarro, Mario G. Abadi, Matthias Steinmetz

We use numerical simulations to investigate the orbital characteristics of tidal debris from satellites whose orbits are dragged into the plane of galactic disks by dynamical friction before disruption. We find that these satellites may deposit a significant fraction of their stars into the disk components of a galaxy, and use our results to motivate the sea

Robert Mann, Cristian Stelea

We discuss and compare at length the results of two methods used recently to describe the thermodynamics of Taub-NUT solutions in a deSitter background. In the first approach ($\mathbb{% C}$-approach), one deals with an analytically continued version of the metric while in the second approach ($\mathbb{R}$-approach), the discussion is carried out using the u

Adrian Vasiu

Let $(G,X)$ be a Shimura pair of Hodge type such that $G$ is the Mumford--Tate group of some elements of $X$. We assume that for each simple factor $G_0$ of $G^{\ad}$ there exists a simple factor of $G_{0\dbR}$ which is compact. Let $N\Ge 3$. We show that for many compact open subgroups $K$ of $G(\dbA_f)$, the Shimura variety $\Sh(G,X)/K$ has a projective in

A. Romanelli, A. Auyuanet, R. Siri, G. Abal

We consider a new model of quantum walk on a one-dimensional momentum space that includes both discrete jumps and continuous drift. Its time evolution has two stages; a Markov diffusion followed by localized dynamics. As in the well known quantum kicked rotor, this model can be mapped into a localized one-dimensional Anderson model. For exceptional (rational

Zheng Zheng, Andreas A. Berlind, David H. Weinberg, Andrew J. Benson

The halo occupation distribution (HOD) describes the relation between galaxies and dark matter at the level of individual dark matter halos. The properties of galaxies residing at the centers of halos differ from those of satellite galaxies because of differences in their formation histories. Using a smoothed particle hydrodynamics (SPH) simulation and a sem

Niayesh Afshordi, Yen-Ting Lin, Alastair J. R. Sanderson

We devise a Monte-Carlo based, optimized filter match method to extract the thermal Sunyaev-Zel&#39;dovich (SZ) signature of a catalog of 116 low-redshift X-ray clusters from the first year data release of the Wilkinson Microwave Anisotropy Probe (WMAP). We detect an over-all amplitude for the SZ signal at the ~ 8-sigma level, yielding a combined constraint

C. Issever, K. Borras, D. Wegener

An improved weighting algorithm applied to hadron showers has been developed for a fine grained LAr calorimeter. The new method uses tabulated weights which depend on the density of energy deposited in individual cells and in a surrounding cone whose symmetry axis connects the interaction vertex with the highest energy cluster in the shower induced by a hadr

Massimo Ricotti, Nickolay Y. Gnedin

We compare the properties of dwarf galaxies in the Local Group with the simulated galaxies formed before reionization in a cosmological simulation of unprecedented spatial and mass resolution,including radiative feedback effects. We find that a subset of the Local Group dwarfs are remarkably similar to the simulated dwarf galaxies in all their properties alr

Tereasa G. Brainerd

The distribution of satellite galaxies relative to isolated host galaxies in the Sloan Digital Sky Survey (SDSS) is investigated. Host-satellite systems are selected using three different methods, yielding samples of ~3300, ~1600, and \~950 satellites. In the plane of the sky, the distributions of all three samples show highly significant deviations from cir

Roi Baer, Daniel Neuhauser

We derive an exact representation of the exchange-correlation energy within density functional theory (DFT) which spawns a class of approximations leading to correct long-range asymptotic behavior. In what amounts to be the simplest approximation, we obtain an electronic structure theory that combines a new local correlation en-ergy (based on Monte-Carlo cal

C. Thompson, A. M. Beloborodov

The recently discovered soft gamma-ray emission from the anomalous X-ray pulsar 1E 1841-045 has a luminosity L_g ~ 10^{36} ergs/s. This luminosity exceeds the spindown power by three orders of magnitude and must be fed by an alternative source of energy such as an ultrastrong magnetic field. A gradual release of energy in the stellar magnetosphere is expecte

Akifumi Sako, Toshiya Suzuki

We investigate SUSY of Wess-Zumino models in non(anti-)commutative Euclidean superspaces. Non(anti-)commutative deformations break 1/2 SUSY, then non(anti-)commutative Wess-Zumino models do not have full SUSY in general. However, we can recover full SUSY at specific coupling constants satisfying some relations. We give a general way to construct full SUSY no

Valentin V. Khoze

We discuss a remarkable new approach initiated by Cachazo, Svrcek and Witten for calculating gauge theory amplitudes. The formalism amounts to an effective scalar perturbation theory which in many cases offers a much simpler alternative to the usual Feynman diagrams for deriving $n$-point amplitudes in gauge theory. At tree level the formalism works in a gen

Paul T. Kondratko, Lincoln J. Greenhill, James M. Moran

We have mapped, for the first time, the full velocity extent of the water maser emission in NGC 3079. The largely north-south distribution of emission, aligned with a kpc-scale molecular disk, and the segregation of blue- and red-shifted emission on the sky are suggestive of a nearly edge-on molecular disk on pc-scales. Positions and line-of-sight velocities

A. K. Giri, R. Mohanta

We analyze the possibility of observing new physics effects in the $b \to d$ penguin amplitudes. For this purpose, we consider the decay mode $B \to K^0 \bar K^0 $, which has only $b \to d$ penguin contributions. Using the QCD factorization approach, we find very tiny CP violating effects in the standard model for this process. Furthermore, we show that the

H. I. Arcos, J. G. Pereira

By using a nonholonomous-frame formulation of the general covariance principle, seen as an active version of the strong equivalence principle, an analysis of the gravitational coupling prescription in the presence of curvature and torsion is made. The coupling prescription implied by this principle is found to be always equivalent with that of general relati

Monique Combescure

In this paper we develop the topics of Quantum Recurrences and of Quantum Fidelity which have attracted great interest in recent years. The return probability is given by the square modulus of the overlap between a given initial wavepacket and the corresponding evolved one; quantum recurrences in time can be observed if this overlap is unity. We provide some

F. S. Navarra, M. Nielsen, K. Tsushima

We consider a $[ud]^2\bar{s}$ current, in the finite-density QCD sum rule approach, to investigate the scalar and vector self-energies of the recently observed pentaquark state $Θ^+(1540)$, propagating in nuclear mater. We find that, opposite to what was obtained for the nucleon, the vector self-energy is negative, and the scalar self-energy is positive. The

Eelco van Kampen, Will J. Percival, Miller Crawford, James S. Dunlop

We present predictions for the angular correlation function and redshift distribution for SHADES, the SCUBA HAlf-Degree Extragalactic Survey, which will yield a sample of around 300 sub-mm sources in the 850 micron waveband in two separate fields. Complete and unbiased photometric redshift information on these sub-mm sources will be derived by combining the

G. W. Gibbons, M. J. Perry, C. N. Pope

We obtain expressions for the mass and angular momenta of rotating black holes in anti-de Sitter backgrounds in four, five and higher dimensions. We verify explicitly that our expressions satisfy the first law of thermodynamics, thus allowing an unambiguous identification of the entropy of these black holes with $\ft14$ of the area. We find that the associat

Dmytro Iakubovskyi, Yuri Shtanov

We consider cosmological solutions and their stability with respect to homogeneous and isotropic perturbations in the braneworld model with the scalar-curvature term in the action for the brane. Part of the results are similar to those obtained by Campos and Sopuerta for the Randall-Sundrum braneworld model. Specifically, the expanding de Sitter solution is

Jan Derezi{ń}ski, Krzysztof A. Meissner

We present a construction of the algebra of operators and the Hilbert space for a quantum massless field in 1+1 dimensions.

Spiros Cotsakis

We study the generic transport of slice energy between the scalar field generated by the conformal transformation of higher-order gravity theories and the matter component. We give precise relations for this exchange in the cases of dust and perfect fluids. We show that, unless we are in a stationary spacetime where slice energy is always conserved, in non-s