January 2003 arXiv papers — page 10

W. Forman, E. Churazov, L. David, F. Durret

We discuss two themes from Chandra and XMM-Newton observations of galaxies, groups, and clusters. First, we review observational aspects of cluster formation and evolution as matter accretes along filaments in A85 and A1367. We describe Chandra observations that probe the later evolutionary phases where the effects of mergers -- both subsonic and supersonic

P. G. Jonker, M. Mendez, G. Nelemans, R. Wijnands

We present our analysis of Chandra observations obtained when the soft X-ray transient RX J170930.2-263927 (XTE J1709-267) returned to quiescence after an outburst. Using the type I burst peak luminosity found by Cocchi et al. (1998) and the value of N_H we derived from our spectral fits, the distance to RX J170930.2-263927 can be constrained to 2.5-10 kpc.

Martin E. Beer, Melvyn B. Davies

We investigate the observed depletion of red giants in the cores of post-core-collapse globular clusters. In particular, the evolutionary scenario we consider is a binary consisting of two low-mass stars which undergoes two common envelope phases. The first common envelope phase occurs when the primary is a red giant resulting in a helium white dwarf and mai

Harriet Cullen, Paul Alexander, Marcel Clemens

Both Arp 140 and Arp 104 reveal extended tidal tails in the HI. The Halpha and FIR fluxes of Arp 140 yield similar SFR of ~0.8 solar masses per year. In contrast the Halpha flux of Arp 104 yields a SFR of ~0.05 solar masses per year, ~ 20 times smaller than that obtained from the FIR flux. Spectra were used to examine the changing velocity of atomic and mole

T. Bulik, K. Belczynski

We estimate the observed distribution of chirp masses of compact object binaries for the gravitational wave detectors. The stellar binary evolution is modeled using the {\em StarTrack} population synthesis code. The distribution of the predicted "observed" chirp masses vary with variation of different parameters describing stellar binary evolution. W

A. C. Fabian, J. S. Sanders, C. S. Crawford, S. Ettori

We report the results from a 200 ks Chandra observation of the z=1.786 radio galaxy 3C294 and its cluster environment, increasing by tenfold our earlier observation. The diffuse emission, extending about 100 kpc around the nucleus, has a roughly hourglass shape in the N-S direction with surprisingly sharp edges to the N and S. The spectrum of the diffuse emi

E. -M. Pauli, R. Napiwotzki, M. Altmann, U. Heber

We present kinematics of a sample of 107 DA white dwarfs from the SPY project and discuss kinematic criteria for a distinction of thin disk, thick disk, and halo populations. This is the first homogeneous sample of white dwarfs for which 3D space motions have been determined. Studies of white dwarf kinematics can help determine the fraction of the total mass

Matthias Stute, Max Camenzind

We present a self-consistent, relativistic model of rapidly rotating neutron stars describing their exterior gravitational field. This is achieved by matching the new solution of Einstein's field equations found by Manko et al. (2000) and the numerical results for the interior of neutron stars with different equations of state calculated by Cook et al. (

M. A. Garrett, J. M. Wrobel, R. Morganti

We present preliminary results from the deepest VLBI observations yet conducted. VLBA+GBT 1.4 GHz observations of a region within NOAO-N, reach an r.m.s. noise level of 9 microJy per beam. Three sources are clearly detected (> 7 sigma) within the inner 2 arcmins of the GBT primary beam, including two sub-mJy sources and the ``in-beam'' calibrator. In

Bart Pindor, Edwin L. Turner, Robert H. Lupton, J. Brinkmann

We present an algorithm for selecting gravitational lens candidates from amongst Sloan Digital Sky Survey (SDSS) quasars. In median Early Data Release (EDR) conditions, the algorithm allows for the recovery of pairs of equal flux point sources down to separations of $\sim 0{\farcs}7$ or with flux ratios up to $\sim$ 10:1 at a separation of $1\farcs5$. The al

Jungyeon Cho, A. Lazarian

Astrophysical turbulence is magnetohydrodynamic (MHD) in its nature. We discuss fundamental properties of MHD turbulence. In particular, we discuss the generation of compressible MHD waves by Alfvenic turbulence and show that this process is inefficient. This allows us to study the evolution of different types of MHD perturbations separately. We describe how

Y. -Z. Qian, G. J. Wasserburg

(Abridged) The stellar sites and the complete mechanism of r-process nucleosynthesis are still unresolved issues. From consideration of the observed abundances in metal-poor stars, it is proposed that the production of the heavy r-process nuclei (with mass numbers A>130) is not related to the production of the Fe group elements or of the elements with lower

J. Greensite

I review investigations of the quark confinement mechanism that have been carried out in the framework of SU(N) lattice gauge theory. The special role of Z(N) center symmetry is emphasized.

E. I. Chiang, A. B. Jordan, R. L. Millis, M. W. Buie

As part of our ongoing Deep Ecliptic Survey (DES) of the Kuiper belt, we report on the occupation of the 1:1 (Trojan), 4:3, 3:2, 7:4, 2:1, and 5:2 Neptunian mean-motion resonances (MMRs). The occupation of the 1:1 and 5:2 MMRs is not easily understood within the standard model of resonance sweeping by a migratory Neptune over an initially dynamically cold be

Monica Rodriguez

This paper presents an analysis of [Fe IV] emission based on new identifications and previous measurements of [Fe IV] lines in 30 Doradus, IC 4846, M42, SMC N88A, and SBS 0335-052. The Fe abundances obtained by adding the abundances of the relevant Fe ions (mainly Fe^{++} and Fe^{3+}) are found to be lower, by factors in the range 2.6-5.9, than the Fe abunda

Dan Pirjol, Carlos Schat

In the large Nc limit, the mass spectrum of the L=1 orbitally excited baryons N* has a very simple structure, with states degenerate in pairs of spins J=(1/2,3/2), (3/2,5/2), corresponding to irreducible representations (towers) of the contracted SU(4)_c symmetry group. The mixing angles are completely determined in this limit. Using a mass operator approach

Jianqiang Zhao

In this paper we will study the p-divisibility of partial sums of multiple zeta value series. In particular we provide some generalizations of the classical Wolstenholme's Theorem.

Christophe Ringeval, Patrick Peter, Jean-Philippe Uzan

We study a six-dimensional braneworld model with infinite warped extra dimensions in the case where the four-dimensional brane is described by a topological vortex of a U(1) symmetry-breaking Abelian Higgs model in presence of a negative cosmological constant. A detailed analysis of the microscopic parameters leading to a finite volume space-time in the extr

J. -C. Bouret, T. Lanz, D. J. Hillier, S. R. Heap

We present the results of a detailed UV and optical spectral analysis of the properties of 6 dwarf O-type stars in the SMC H II region NGC 346. Stellar parameters, chemical abundances, and wind parameters have been determined using NLTE line blanketed models calculated with the photospheric code, Tlusty, and with the wind code, CMFGEN. The results, in partic

A. Zheludev, Z. Honda, C. Broholm, K. Katsumata

Inelastic neutron scattering experiments on the Haldane-gap quantum antiferromagnet \nd are performed at mK temperatures in magnetic fields of almost twice the critical field $H_c$ applied perpendicular to the spin cahins. Above $H_c$ a re-opening of the spin gap is clearly observed. In the high-field Néel-ordered state the spectrum is dominated by three dis

Robert E. Rutledge, Derek W. Fox, S. R. Kulkarni, Bryan A. Jacoby

We perform absolute timing of PSR B1821-24 in M28, using a 50 ksec observation with Chandra/HRC-S. We have obtained the highest signal-to-noise X-ray pulsed lightcurve of this source to date, detecting two X-ray pulses, as well as significant non-pulsed emission -- a persistent X-ray flux which comprises 15+/-3% of the total X-ray flux of the pulsar. The Gau

S. Shankaranarayanan

In the light of recent interest in quantum gravity in de Sitter space, we investigate semi-classical aspects of 4-dimensional Schwarzschild-de Sitter space-time using the method of complex paths. The standard semi-classical techniques (such as Bogoliubov coefficients and Euclidean field theory) have been useful to study quantum effects in space-times with si

Richard Massey, Alexandre Refregier, Christopher J. Conselice, David J. Bacon

We present a method to simulate deep sky images, including realistic galaxy morphologies and telescope characteristics. To achieve a wide diversity of simulated galaxy morphologies, we first use the shapelets formalism to parametrize the shapes of all objects in the Hubble Deep Fields. We measure this distribution of real galaxy morphologies in shapelet para

R. Arndt, W. Briscoe, I. Strakovsky, R. Workman

We have performed a series of global and single-Q2 fits to the growing database for pion electroproduction. We compare to some other recent fits which have used different formalisms, more selective datasets, and truncated multipole expansions. We present results for the E2/M1 and S2/M1 ratios, as a function of Q2.

Pochung Chen, C. Piermarocchi, L. J. Sham, D. Gammon

We present a theory of quantum optical control of an electron spin in a single semiconductor quantum dot via spin-flip Raman transitions. We show how an arbitrary spin rotation may be achieved by virtual excitation of discrete or continuum trion states. The basic physics issues of the appropriate adiabatic optical pulses in a static magnetic field to perform

J. Bartels, K. Golec-Biernat, K. Peters

We calculate, for nonzero momentum transfer, the dipole formula for the high energy behaviour of elastic and quasielastic scattering of a virtual photon. We obtain an expression of the nonforward photon impact factor and of the nonforward photon wave function, and we give a physical interpretation.

R. Farinelli, F. Frontera, N. Masetti, L. Amati

Observations of two unclassified Low Mass X-ray Binaries, X1543-624 and X1556-605, are presented. In the 2-10 keV band the first of the two sources is a factor two stronger than the other. Both sources do not show X-ray bursts, dips or eclipses in their X-ray light curves. We find that both spectra are described by a two-component model consisting of emissio

A. Denner, S. Dittmaier, M. Roth, M. M. Weber

We have calculated the complete electroweak O(alpha) radiative corrections to the single Higgs-boson production processes e+ e- --> nu_l anti-nu_l H (l=e,mu,tau) in the electroweak Standard Model. Initial-state radiation beyond O(alpha) is included in the structure-function approach. The calculation of the corrections is briefly described, and numerical resu

Makoto Tsubota, Tsunehiko Araki, Carlo. F. Barenghi

Almost all studies of vortex states in helium II have been concerned with either ordered vortex lattices or disordered vortex tangles. This work studies numerically what happens in the presence of both rotation (which induces order) and thermal counterflow (which induces disorder). We find a new statistically steady state in which the vortex tangle is polari

I. Heckenberger, S. Kolb

The notion of locally finite part of the dual coalgebra of certain quantized coordinate rings is introduced. In the case of irreducible flag manifolds this locally finite part is shown to coincide with a natural quotient coalgebra V of U_q(g). On the way the coradical filtration of V is determined. A graded version of the duality between V and the quantized

Hideaki Kudoh, Takahiro Tanaka, Takashi Nakamura

No realistic black holes localized on a 3-brane in the Randall-Sundrum infinite braneworld have been found so far. The problem of finding a static black hole solution is reduced to a boundary value problem. We solve it by means of a numerical method, and show numerical examples of a localized black hole whose horizon radius is small compared to the bulk curv

T. Multamaki, I. Vilja

We study cosmological aspects of braneworld models with a warped dimension and an arbitrary number of compact dimensions. With a stabilized radion, a number of different cosmological bulk solutions are found in a general case. Both one and two brane models are considered. The Friedmann equation is calculated in each case. Particular attention is paid to six

Y. -H. Kim, M. Barth, U. Kuhl, H. -J. Stoeckmann

Using the equivalence between the quantum-mechanical probability density in a quantum billiard and the Poynting vector in the corresponding microwave system, current distributions were studied in a quantum dot like cavity, as well as in a Robnik billiard with lambda=0.4, and an introduced ferrite cylinder. Spatial auto correlation functions for currents and

F. Canfora, G. Vilasi

Non-vacuum exact gravitational waves invariant for a non Abelian two-dimensional Lie algebra generated by two Killing fields whose commutator is of light type, are described. The polarization of these waves, already known from previous works, is related to the sources. Non vacuum exact gravitational waves admitting only one Killing field of light type are al

Kazuya Koyama, Keitaro Takahashi

An inflationary brane model driven by a bulk inflaton with exponential potential is proposed. We find a family of exact solutions that describe power-law inflation on the brane. These solutions enable us to derive exact solutions for metric perturbations analytically. By calculating scalar and tensor perturbations, we obtain a spectrum of primordial fluctuat

Eric G. Blackman

Recent MHD dynamo simulations for magnetic Prandtl number $>1$ demonstrate that when MHD turbulence is forced with sufficient kinetic helicity, the saturated magnetic energy spectrum evolves from having a single peak below the forcing scale to become doubly peaked with one peak at the system (=largest) scale and one at the forcing scale. The system scale fie

Tohru Eguchi, Yuji Sugawara, Satoshi Yamaguchi

We study aspects of superstring vacua of non-compact special holonomy manifolds with conical singularities constructed systematically using soluble N = 1 superconformal field theories (SCFT's). It is known that Einstein homogeneous spaces G/H generate Ricci flat manifolds with special holonomies on their cones R_+ x G/H, when they are endowed with approp

Farhad H Jafarpour

A coagulation-decoagulation model is introduced on a chain of length L with open boundary. The model consists of one species of particles which diffuse, coagulate and decoagulate preferentially in the leftward direction. They are also injected and extracted from the left boundary with different rates. We will show that on a specific plane in the space of par

A. Sajina, C. Borys, S. Chapman, H. Dole

We present results from JCMT sub-mm observations of sources selected from the {\sl ISO} FIRBACK (Far-IR BACKground) survey, along with UKIRT near-IR imaging of a sub-sample. This gives valuable insight into the brightest $\sim$10% of galaxies which contribute to the Cosmic Infrared Background (CIB). We estimate the photometric redshifts and luminosities of t

Jose Gaite

Quantum entanglement entropy has a geometric character. This is illustrated by the interpretation of Rindler space or black hole entropy as entanglement entropy. In general, one can define a "geometric entropy", associated with an event horizon as a boundary that concentrates a large number of quantum states. This allows one to connect with the "

Samuel Colin

In a paper entitled Beables for Quantum Field Theory, John Bell has shown that it was possible to build a realistic interpretation of any hamiltonian lattice quantum field theory involving Fermi fields. His model is stochastic but Bell thought that it would become deterministic in the continuum limit. We show that it is indeed the case, under an assumption a

Zhi Zhao, Tao Yang, Yu-Ao Chen, An-Ning Zhang

We report an experimental realization of entanglement concentration using two polarization-entangled photon pairs produced by pulsed parametric down-conversion. In the meantime, our setup also provides a proof-in-principle demonstration of a quantum repeater. The quality of our procedure is verified by observing a violation of Bell's inequality by more t

J. J. Halliwell

A brief introduction to the decoherent histories approach to quantum theory is given, with emphasis on its role in the discussion of the emergence of classicality from quantum theory. Some applications are discussed, including quantum-classical couplings, the relationship of the histories approach to quantum state diffusion, and the application of the histor

Armin Uhlmann

The topics of the paper are: a) Some anti-linear maps governing EPR tasks if no reference bases are distinguished. b) Imperfect teleportation and the composition rule. The ancilla is supposed pure but otherwise arbitrary. c) Quantum telportation with distributed measurements. d) Remarks on EPR with a mixed state, triggered by a Lueders measurement.

N. V. Brazovskaja, V. Ye. Brazovsky

We construct Dirac-like equation for describing two-level atom interacting with resonant laser field.

A. L. Perez Prieto, S. Brouard, J. G. Muga

The collision of a quantum Gaussian wave packet with a square barrier is solved explicitly in terms of known functions. The obtained formula is suitable for performing fast calculations or asymptotic analysis. It also provides physical insight since the description of different regimes and collision phenomena typically requires only some of the terms.

A. Gilchrist, W. J. Munro, A. G. White

We examine three possible implementations of non-deterministic linear optical cnot gates with a view to an in-principle demonstration in the near future. To this end we consider demonstrating the gates using currently available sources such as spontaneous parametric down conversion and coherent states, and current detectors only able to distinguish between z

Paul B. Slater

In a previous study (quant-ph/9911058), several remarkably simple exact results were found, in certain specialized m-dimensional scenarios (m<5), for the a priori probability that a pair of qubits is unentangled/separable. The measure used was the volume element of the Bures metric (identically one-fourth the statistical distinguishability [SD] metric). Here

Frank Verstraete, Henri Verschelde

One of the most challenging open problems in quantum information theory is to clarify and quantify how entanglement behaves when part of an entangled state is sent through a quantum channel. Of central importance in the description of a quantum channel or completely positive map (CP-map) is the dual state associated to it. The present paper is a collection o

M. Ignaccolo, P. Allegrini, P. Grigolini, P. Hamilton

Most data processing techniques, applied to biomedical and sociological time series, are only valid for random fluctuations that are stationary in time. Unfortunately, these data are often non stationary and the use of techniques of analysis resting on the stationary assumption can produce a wrong information on the scaling, and so on the complexity of the p

Mark A. Iron, Mikhal Oren, Jan M. L. Martin

Core-valence basis sets for the alkali and alkaline earth metals Li, Be, Na, Mg, K, and Ca are proposed. The basis sets are validated by calculating spectroscopic constants of a variety of diatomic molecules involving these elements. Neglect of $(3s,3p)$ correlation in K and Ca compounds will lead to erratic results at best, and chemically nonsensical ones i

Miroslaw Latka, Marta Glaubic-Latka, Dariusz Latka, Bruce J. West

We study the middle cerebral artery blood flow velocity (MCAfv) in humans using transcranial Doppler ultrasonography (TCD). Scaling properties of time series of the axial flow velocity averaged over a cardiac beat interval may be characterized by two exponents. The short time scaling exponent (STSE) determines the statistical properties of fluctuations of bl

C. Noli, J. N. L. Connor

We report a new resummation procedure for the partial wave series (PWS) representation of the scattering amplitude, when a basis set of Legendre polynomials is used for the expansion. The effect of the resummation is to remove from the PWS the factor containing alpha and beta. The resummed scattering amplitude is then exactly decomposed into the sum of a nea

Helene Yockell-Lelievre, Ermanno F. Borra, Anna Ritcey, Lande Vieira da Silva

We describe a new technology for the fabrication of inexpensive high-quality mirrors. We begin by chemically producing a large number of metallic nanoparticles coated with organic ligands. The particles are then spread on a liquid substrate where they self-assemble to give optical quality reflective surfaces. Since liquid surfaces can be modified with a vari

A. Taichenachev, V. Yudin, R. Wynands, M. Stahler

We develop an analytical theory of dark resonances that accounts for the full atomic-level structure, as well as all field-induced effects such as coherence preparation, optical pumping, ac Stark shifts, and power broadening. The analysis uses a model based on relaxation constants that assumes the total collisional depolarization of the excited state. A good

J. Dobaczewski

An introduction to nuclear theory is given starting from the quantum chromodynamics foundations for quark and gluon fields, then discussing properties of pions and nucleons, interactions between nucleons, structure of the deuteron and light nuclei, and finishing at the description of heavy nuclei. It is shown how concepts of different energy and size scales

M. Reiter, E. L. Bratkovskaya, M. Bleicher, W. Bauer

The isospin and strangeness dimensions of the Equation of State are explored. RIA and the SIS200 accelerator at GSI will allow to explore these regions in compressed baryonic matter. $^{132}$Sn+$^{132}$Sn and $^{100}$Sn+$^{100}$Sn collisions as well as the excitation functions of $K/π$, $Λ/π$ and the centrality dependence of charmonium suppression from the U

Christopher Manderfeld

We study the correspondence between phase-space localization of quantum (quasi-)energy eigenstates and classical correlation decay, given by Ruelle-Pollicott resonances of the Frobenius-Perron operator. It will be shown that scarred (quasi-)energy eigenstates are correlated: Pairs of eigenstates strongly overlap in phase space (scar in same phase-space regio

M. Thiel, M. C. Romano, J. Kurths

We present an analytical description of the distribution of diagonal lines in Recurrence Plots (RPs) for white noise and chaotic systems, and find that the latter one is linked to the correlation entropy. Further we identify two scaling regions in the distribution of diagonals for oscillatory chaotic systems that are hinged to two prediction horizons and to

Francisco J. Beron-Vera, Michael G. Brown, John A. Colosi, Steven Tomsovic

A ray-based wavefield description is employed in the interpretation of measurements made during the November 1994 Acoustic Engineering Test (the AET experiment). In this experiment phase-coded pulse-like signals with 75 Hz center frequency and 37.5 Hz bandwidth were transmitted near the sound channel axis in the eastern North Pacific Ocean. The resulting aco

Ali Mostafazadeh

An error in the paper [J. Math. Phys. 43, 6343 (2002); math-ph/0207009] is corrected. Further explanation is given.

T. Kajiwara, C. Pinzari, Y. Watatani

We introduce the notion of finite right (respectively left) numerical index on a bimodule $X$ over C*-algebras A and B with a bi-Hilbertian structure. This notion is based on a Pimsner-Popa type inequality. The right (respectively left) index element of X can be constructed in the centre of the enveloping von Neumann algebra of A (respectively B). X is calle

Michael M. Medynski

One of the actual problems in the field of numerical optimisation, as is well known, is the problem of the search for the global extremum of a multivariate function [1-9,13,14,17-21]. Various versions of the random search methods [6,8,9] are considered to be the most reliable to solve the problem of global optimisation. In this work we present the little-kno

Luis David Garcia, Michael Stillman, Bernd Sturmfels

We study the algebraic varieties defined by the conditional independence statements of Bayesian Networks. A complete algebraic classification is given for Bayesian Networks on at most five random variables. Hidden variables are related to the geometry of higher secant varieties.

Aobing Li, YanYan Li

We present some further results on Liouville type theorems for some conformally invariant fully nonlinear equations.

K. Szlachanyi

Every monoidal functor G: C --> M has a canonical factorization through the category of bimodules over some monoid R in M such that the factor U: C -->_R M_R is strongly unital. Using this result and the characterization of the forgetful functors M_A -->_R M_R of bialgebroids A over R given by Schauenburg together with their bimonad description given by the

Michael Nakamaye

We examine how the Seshadri constant of an ample line bundle at a very general point of an algebraic surface can carry important global geometric information about the surface. In particular, we obtain a numerical criterion for when a surface admits a dominant map to an algebraic curve.

R. Ghrist, E. Kin

We consider vector fields on knot/link complements in $S^3$ which are transverse to the fibres of a fibration of the complement over a circle. We prove that a large class of fibred knots/links, including all non-torus fibred 2-bridge knots, has the following property: any vector field transverse to the fibres of the fibration of the complement must possess p

Andrew Kresch, Angelo Vistoli

This paper proves a result on the existence of finite flat scheme covers of Deligne-Mumford stacks. This result is used to prove that a large class of smooth Deligne-Mumford stacks with affine moduli space are quotient stacks, and in the case of quasi-projective moduli space, to reduce the question to one concerning Brauer groups of schemes.

Teimuraz Pirashvili

In this paper we consider dimonoids, which are sets equipped with two associative binary operations. Dimonoids in the sense of J.-L. Loday are xamples of duplexes. The set of all permutations, gives an example of a duplex which is not a dimonoid. We construct a free duplex generated by a given set via planar trees and then we prove that the set of all permut

Aleksandar Mijatovic

It is not completely unreasonable to expect that a computable function bounding the number of Pachner moves needed to change any triangulation of a given 3-manifold into any other triangulation of the same 3-manifold exists. In this paper we describe a procedure yielding an explicit formula for such a function if the 3-manifold in question is a Seifert fibre

V. Kharlamov, S. Orevkov

The number of topologically different plane real algebraic curves of a given degree $d$ has the form $\exp(C d^2 + o(d^2))$. We determine the best available upper bound for the constant $C$. This bound follows from Arnold inequalities on the number of empty ovals. To evaluate its rate we show its equivalence with the rate of growth of the number of trees hal

Kirsten Eisentraeger, Kristin Lauter, Peter L. Montgomery

We present an algorithm which speeds scalar multiplication on a general elliptic curve by an estimated 3.8 % to 8.5 % over the best known general methods when using affine coordinates. This is achieved by eliminating a field multiplication when we compute 2P+Q from given points P, Q on the curve. We give applications to simultaneous multiple scalar multiplic

Tomas L. Gomez, Ignacio Sols

Let G be a connected reductive group. The late Ramanathan gave a notion of (semi)stable principal G-bundle on a complex projective curve and constructed a projective moduli space of such objects. We generalize Ramanathan&#39;s notion and construction to the case of higher dimension, allowing also objects which we call semistable principal G-sheaves.

Saso Strle

In this paper we present a way of computing a lower bound for genus of any smooth representative of a homology class of positive self-intersection in a smooth four-manifold $X$ with second positive Betti number $b_2^+(X)=1$. We study the solutions of the Seiberg-Witten equations on the cylindrical end manifold which is the complement of the surface represent

Tomas L. Gomez, Ignacio Sols

Let X be a smooth projective variety over C. We find the natural notion of semistable orthogonal bundle and construct the moduli space, which we compactify by considering also orthogonal sheaves, i.e. pairs (E,ϕ), where E is a torsion free sheaf on X and ϕis a symmetric nondegenerate (in the open set where E is locally free) bilinear form on E. We also consi

Wolfgang Mück

The Maldacena-Nunez solution is generalized to include a number of integration constants, one of which controls the resolution of the singularity of the wrapped D5-brane background. Some features of the dual pure N=1 super Yang-Mills (SYM) theory are calculated, amongst which the gluino condensate, the beta function of the gauge coupling and a brane probe po

Thierry Grandou

It is shown that three series of diagrams entering the calculation of some hot $QCD$ process, are mass (or collinear) singularity free, indeed. This generalizes a result which was recently established up to the third non trivial order of (thermal) Perturbation Theory.

J. Spinelly, E. R. Bezerra de Mello

In this paper we consider a charged massless scalar quantum field operator in the spacetime of an idealized cosmic string, i.e., an infinitely long, straight and static cosmic string, which presents a magnetic field confined in a cylindrical tube of finite radius. Three distinct situations are taking into account in this analysis: {\it{i)}} a homogeneous fie

Francesco Toppan

The generalized supersymmetries admitting abelian bosonic tensorial central charges are classified in accordance with their division algebra structure (over ${\bf R}$, ${\bf C}$, ${\bf H}$ or ${\bf O}$). It is shown in particular that in D=11 dimensions, the $M$-superalgebra admits a consistent octonionic formulation, involving 52 real bosonic generators (in

Frank Ferrari

In [1] (hep-th/0211069), the author has discussed the quantum parameter space of the N=1 super Yang-Mills theory with one adjoint Higgs field Phi, tree-level superpotential W_tree = m (Phi^2)/2 + g (Phi^3)/3$, and gauge group U(Nc). In particular, full details were worked out for U(2) and U(3). By discussing higher rank gauge groups like U(4), for which the

Christos Kokorelis

We analyze the construction of non-supersymmetric three generation six-stack Pati-Salam (PS) $SU(4)_C \times SU(2)_L \times SU(2)_R$ GUT classes of models, by localizing D6-branes intersecting at angles in four dimensional orientifolded toroidal compactifications of type IIA. Special role in the models is played by the presence of extra branes needed to sati

A. A. Slavnov, K. V. Stepanyantz

Manifestly invariant renormalization scheme for supersymmetric gauge theories is proposed. This scheme is applied to supersymmetric quantum electrodynamics.

M. de Montgny, F. C. Khanna, A. E. Santana

Using a Galilean metric approach, based in an embedding of the Euclidean space into a (4+1)-Minkowski space, we analyze a gauge invariant Lagrangian associated with a Riemannian manifold R, with metric g. With a specific choice of the gauge condition, the Euler-Lagrange equations are written covariantly in R, and then the Fokker-Planck equation is derived, s

Xin-Nian Wang

Medium modification of jet fragmentation function due to multiple scattering and induced gluon radiation leads directly to jet quenching or suppression of leading particle distribution from jet fragmentation. One can extract an effective total parton energy loss which can be related to the total transverse momentum broadening. For an expanding medium, both a

Ben-Wei Zhang, Xin-Nian Wang

Multiple parton scattering and induced parton energy loss in deeply inelastic scattering (DIS) off heavy nuclei is studied within the framework of generalized factorization in perturbative QCD with a complete calculation beyond the helicity amplitude (or soft bremsstrahlung) approximation. Such a calculation gives rise to new corrections to the modified quar

P. Giovannangeli, C. P. Korthals Altes

Spatial &#39;t Hooft loops of strength k measure the qualitative change in the behaviour of electric colour flux in confined and deconfined phase of SU(N) gauge theory. They show an area law in the deconfined phase, known analytically to two loop order with a ``k-scaling&#39;&#39; law k(N-k). In this paper we compute the O(g^3) correction to the tension. It

A. Bashir

Schwinger-Dyson equations (SDEs) provide a natural staring point to study non-perturbative phenomena such as dynamical chiral symmetry breaking in gauge field theories. We briefly review this research in the context of quenched quantum electrodynamics (QED) and discuss the advances made in the gradual improvement of the assumptions employed to solve these eq

Orfeu Bertolami

Evidence on the violation of Lorentz symmetry arises from the observation of cosmic rays with energies beyond the GZK cutoff, $E_{GZK} \simeq 4 \times 10^{19} eV$, from the apparent transparency of the Universe to the propagation of high energy gamma radiation and from the stability of pions in air showers. These three paradoxes can be explained through defo

I. Haysak, Yu. Fekete, V. Morokhovych, S. Chalupka

Based on the numeric solution of a system of coupled channels for vector mesons ($S$- and $D$-waves mixing) and for tensor mesons ($P$- and $F$-waves mixing) mass spectrum and wave functions of a family of vector mesons $q\bar{q}$ in triplet states are obtained. The calculations are performed using a well known Cornell potential with a mixed Lorentz-structur

D. Koudela, C. Volpe

We study the nuclear medium effects on the $c\bar{c}$ time evolution and charmonium production, in a relativistic proton-nucleus collision. In particular, we focus on the fragmentation region of the nucleus where the formation length of the charmonium mesons is shorter than the size of the nucleus. Little is known on the nuclear effects in this region. We us

Steven Gottlieb, Sonali Tamhankar

We present results from a lattice study of the semileptonic decay $Λ_b \to Λ_c l ν_l $. We use $O(a^2, α_s a^2)$ improved quenched lattices of the MILC collaboration, with lattice spacing $\sim 0.13$ fm. For the valence quarks, the tadpole-improved clover action is used, with the Fermilab method employed for the heavy quarks. Form factors are extracted from

Ramin G. Daghigh

In the first part of this thesis the relativistic viscous fluid equations describing the outflow of high temperature matter created via Hawking radiation from microscopic black holes are solved numerically for a realistic equation of state. We focus on black holes with initial temperatures greater than 100 GeV and lifetimes less than 6 days. The spectra of d

Kirill A. Bronnikov, Boris E. Meierovich

We consider a spherically symmetric global monopole in general relativity in $(D=d+2)$-dimensional spacetime. The monopole is shown to be asymptotically flat up to a solid angle defect in case $γ< d-1$, where $γ$ is a parameter characterizing the gravitational field strength. In the range $d-1< γ< 2d(d+1)/(d+2)$ the monopole space-time contains a cosmologica

Raymond Y. Chiao

One of the conceptual tensions between quantum mechanics (QM) and general relativity (GR) arises from the clash between the spatial nonseparability} of entangled states in QM, and the complete spatial separability of all physical systems in GR, i.e., between the nonlocality implied by the superposition principle, and the locality implied by the equivalence p

Burc Gokden

In this paper we develop a formalism which models all massive particles as travelling at the speed of light(c). This is done by completing the 3-velocity v of a test particle to the speed of light by adding an auxiliary 3-velocity component z for the particle. According to the observations and laws of physics defined in our spacetime these vectors are genera

Lei Shi, Dimitrios A. Papaconstantopoulos, Michael J. Mehl

Calculations of the electron-phonon interaction in the alkali metals, Potassium and Rubidium, using the results of band theory and BCS theory-based techniques suggest that at high pressures K and Rb would be superconductors with transition temperatures approaching 10 K.

T. Imai, F. C. Chou

We have investigated the spin fluctuations and their interplay with lattice instabilities in a layered S=1/2 quantum spin system TiOCl. Our Ti and Cl NMR data demonstrate a pseudo spin-gap behavior below T*=135 K, followed by successive phase transitions at T_c1=94K and T_c2=66K into the singlet ground state with an unusually large energy gap E_g=430K. The b

D. V. Shopova, D. I. Uzunov

Several basic problems of the theory of quantum phase transitions are reviewed. The effect of the quantum correlations on the phase transition properties is considered with the help of basic models of statistical physics. The effect of quenched disorder on the quantum phase transitions is also discussed. The review is performed within the framework of the th

I. Mazilu, B. Schmittmann

Based directly on the microscopic lattice dynamics, a simple high temperature expansion can be devised for non-equilibrium steady states. We apply this technique to investigate the disordered phase and the phase diagram for a driven bilayer lattice gas at half filling. Our approximation captures the phases first observed in simulations, provides estimates fo