March 2004 arXiv papers — page 8

P. J. Silva, O. Oliveira

We address the problem of Gribov copies in lattice QCD. The gluon propagator is computed, in the Landau gauge, using 302 ($β= 5.8$) $12^4$ configurations gauge fixed to different copies. The results of the simulation shows that: i) the effect of Gribov copies is small (less than 10%); ii) Gribov copies change essentially the lowest momenta components ($q < 2

Alexander Poltorak

The Energy Problem (EP) in General Relativity (GR) is analyzed in the context of GR&#39;s axiomatic inconsistencies. EP is classified according to its local and global aspects. The local aspects of the EP include noncovariance of the energy-momentum pseudotensor (EMPT) of the gravitational field, non-uniqueness of the EMPT, asymmetry of EMPT, and vanishing m

Martin Bojowald, James E. Lidsey, David J. Mulryne, Parampreet Singh

In loop quantum gravity, modifications to the geometrical density cause a self-interacting scalar field to accelerate away from a minimum of its potential. In principle, this mechanism can generate the conditions that subsequently lead to slow-roll inflation. The consequences for this mechanism of various quantization ambiguities arising within loop quantum

Alexandr Ageev, Belkis Cabrera Palmer, Antonio De Felice, Steven D. Penn

We present the results of quality factor measurements for rod samples made of fused silica. To decrease the dissipation we annealed our samples. The highest quality factor that we observed was $Q=(2.03\pm0.01)\times10^8$ for a mode at 384 Hz. This is the highest published value of $Q$ in fused silica measured to date.

G. Zet, C. D. Oprisan, S. Babeti

A de-Sitter gauge theory of the gravitational field is developed using a spherical symmetric Minkowski space-time as base manifold. The gravitational field is described by gauge potentials and the mathematical structure of the underlying space-time is not affected by physical events. The field equations are written and their solutions without singularities a

L. Fernandez-Jambrina, F. J. Chinea

A method for interpreting discontinuities of the twist potential of vacuum stationary axisymmetric solutions of Einstein&#39;s equations is introduced. Surface densities for the angular momentum of the source can be constructed after solving a linear partial differential equation with boundary conditions at infinity. This formalism is applied to the Kerr met

James M. Nester, Fei-Hong Ho, Chiang-Mei Chen

Asymptotically flat gravitating systems have 10 conserved quantities, which lack proper local densities. It has been hoped that the teleparallel equivalent of Einstein&#39;s GR (TEGR, aka GR${}_{||}$) could solve this gravitational energy-momentum localization problem. Meanwhile a new idea: quasilocal quantities, has come into favor. The earlier quasilocal i

Clifford M Will, Nicolas Yunes

We investigate the possible bounds which could be placed on alternative theories of gravity using gravitational wave detection from inspiralling compact binaries with the proposed LISA space interferometer. Specifically, we estimate lower bounds on the coupling parameter ωof scalar-tensor theories of the Brans-Dicke type and on the Compton wavelength of the

Guy Melancon, Fabrice Philippe

We describe a simple algorithm based on a Markov chain process to generate simply connected acyclic directed graphs over a fixed set of vertices. This algorithm is an extension of a previous one, designed to generate acyclic digraphs, non necessarily connected.

Kia l. Ngai, Simone Capaccioli

It is well known that the α-relaxation of each component in a miscible mixtures of two glass-formers has its own dynamics, which change with the composition of the blend. Lesser known are the corresponding change of the Johari-Goldstein (JG) β-relaxation and its relation to the α-relaxation. Previously, in neat glass-formers, the relaxation time \tauJG of JG

R. E. Grisenti, M. Kaesz, J. P. Toennies, G. Benedek

The particle flux through a two micron diameter orifice into vacuum from a source chamber filled with solid He exhibits a striking periodic behavior similar to that of a geyser. This phenomenon is attributed to a periodic collapse of the solid inside the source induced by the accumulation of excess vacancies injected at the orifice. The flux-time curves agre

S. D. Ganichev, S. N. Danilov, Petra Schneider, V. V. Bel&#39;kov

A longstanding theoretical prediction is the orientation of spins by an electrical current flowing through low-dimensional carrier systems of sufficiently low crystallographic symmetry. Here we show by means of terahertz transmission experiments through two-dimensional hole systems a growing spin orientation with an increasing current at room temperature.

B. Ujfalussy, B. Lazarovits, L. Szunyogh, G. M. Stocks

In order to search for the magnetic ground state of surface nanostructures we extended first principles adiabatic spin dynamics to the case of fully relativistic electron scattering. Our method relies on a constrained density functional theory whereby the evolution of the orientations of the spin-moments results from a semi-classical Landau-Lifshitz equation

S. Maximov, M. Gbordzoe, H. Buhmann, L. W. Molenkamp

The low magnetic field diffusion thermopower of a high mobility GaAs-heterostructure has been measured directly on an electrostatically defined micron-scale Hall-bar structure at low temperature (T = 1.6 K) in the low magnetic field regime (B < 1.2 T) where delocalized quantum Hall states do not influence the measurements. The sample design allowed the deter

Carsten Honerkamp, Daniel Rohe, Sabine Andergassen, Tilman Enss

We propose an interaction flow scheme that sums up the perturbation expansion of many-particle systems by successively increasing the interaction strength. It combines the unbiasedness of renormalization group methods with the simplicity of straight-forward perturbation theory. Applying the scheme to fermions in one dimension and to the two-dimensional Hubba

G. -M. Zhang, R. Lu, Z. -R. Liu, L. Yu

Strong electron and spin correlations are studied in parallel-coupled double quantum dots with interdot spin superexchange $J$. In the Kondo regime with {\it}{degenerate} dot energy levels, a coherent transport occurs at zero temperature, where two entangled (bonding and antibonding) resonances are formed near the Fermi energy. When increasing $J$ or the dot

W. E. Bailey, L. Cheng, H. Song

We present direct evidence for the contribution of local orbital moments to the damping of magnetization precession in magnetic thin films. Using x-ray magnetic circular dichroism (XMCD) characterization of rare-earth (RE) M$_{4,5}$ edges in Ni$_{81}$Fe$_{19}$ doped with $<$ 2% Gd and Tb, we show that the enhancement of GHz precessional relaxation is accompa

Tomo Munehisa, Yasuko Munehisa

We apply the recursive stochastic state selection method, which is a new method for Monte Carlo study we have recently developed, to quantum spin systems with positive definite Hamiltonians. Through numerical studies of two-dimensional J1-J2 Heisenberg model on a square lattice with unfrustrated couplings J1=1 and J2=-1 and with non-frustrated ones J1=1 and

A. Honecker, J. Schulenburg, J. Richter

Plateaus can be observed in the zero-temperature magnetization curve of quantum spin systems at rational values of the magnetization. In one dimension, the appearance of a plateau is controlled by a quantization condition for the magnetization which involves the length of the local spin and the volume of a translational unit cell of the ground state. We disc

Trevor Fenner, Mark Levene, George Loizou

Recently several authors have proposed stochastic evolutionary models for the growth of the web graph and other networks that give rise to power-law distributions. These models are based on the notion of preferential attachment leading to the ``rich get richer&#39;&#39; phenomenon. We present a generalisation of the basic model by allowing deletion of indivi

A. Gal-Yam, D. -S. Moon, D. B. Fox, A. M. Soderberg

At z=0.1055, the gamma-ray burst GRB 031203 is one of the two nearest GRBs known. Using observations from the Very Large Array (VLA) and Chandra X-ray Observatory, we derive sub-arcsecond localizations of the radio and X-ray afterglow of this GRB. We present near-infrared observations of the supernova SN 2003lw, which exploded in the host galaxy of the GRB 0

Robert Content

A new design is proposed for large (up to 6-m) liquid mirror containers. The design uses Kevlar, foam and aluminum, as in previous designs, but with a different configuration that makes the container lighter, stronger and more rigid. The results of finite element analysis are presented, consisting in the deformations due to temperature changes and to weight,

Brian E. Wood, Jeffrey L. Linsky, Guillaume Hebrard, Gerard M. Williger

We analyze interstellar absorption observed towards two subdwarf O stars, JL 9 and LSS 1274, using spectra taken by the Far Ultraviolet Spectroscopic Explorer (FUSE). Column densities are measured for many atomic and molecular species (H I, D I, C I, N I, O I, P II, Ar I, Fe II, and H2), but our main focus is on measuring the D/H ratios for these extended li

E. F. Borra, R. Content, G. Tremblay, A. Daigle

We give a generic description of a liquid mirror system and summarize some practical information useful to making them. We compare laboratory measurements of deformations, due to the weight of mercury on the container of a 3.7-m mirror and to temperature changes on a 1-m container, to finite element computer simulations. We find that the measurements agree r

Gustavo A. Lanfranchi, Francesca Matteucci

We predict the metallicity distribution of stars and the age-metallicity relation for 6 Dwarf Spheroidal (dSph) galaxies of the Local Group by means of a chemical evolution model which is able to reproduce several observed abundance ratios and the present day total mass and gas content of these galaxies. The model adopts up to date nucleosynthesis and takes

M. Salaris, M. Riello, S. Cassisi, G. Piotto

We estimate the initial He content in about 30% of the Galactic globular clusters (GGCs) from new star counts we have performed on the recently published HST snapshot database of Colour Magnitude Diagrams (Piotto et al. 2002). More in detail, we use the so-called $R$-parameter and estimate the He content from a calibration based on a recently updated set of

Marco Masi

We show that the effects of radial galactic tides alone can change the dynamics of an Oort cloud of comets around a star in a highly sensitive manner. The Oort cloud dynamics depends primarily from the star&#39;s position in the Galaxy and its mass. The dynamical variation is characterized by a dramatic change of comet perihelia, many of which are shifted to

M. Boettcher

Our recent progress on time-dependent modeling of the multiwavelength spectra and variability of blazars with leptonic and hadronic jet models is reviewed. Special emphasis is placed on X-ray spectral variability of low-frequency peaked (LBLs) and intermediate BL Lac objects (IBLs). As an example, recent observational and modeling results of an extensive mul

R. Napiwotzki, L. Yungelson, G. Nelemans, T. R. Marsh

We report on systematic radial velocity surveys for white dwarf - white dwarf binaries (double degenerates - DDs) including SPY (ESO Supernovae Ia progenitor survey) recently carried out at the VLT. A large sample of DD will allow us to put strong constrains on the phases of close binary evolution of the progenitor systems and to perform an observational tes

K. Tsuchiya, R. Enomoto, L. T. Ksenofontov, M. Mori

We have detected sub-TeV gamma-ray emission from the direction of the Galactic Center (GC) using the CANGAROO-II Imaging Atmospheric Cherenkov Telescope (IACT). We detected a statistically signicant excess at energies greater than 250GeV. The flux was one order of magnitude lower than that of Crab at 1 TeV with a soft spectrum E^{-4.6+-0.5}. The signal centr

T. Bensby, S. Feltzing, I. Lundstrom

A sample of 229 nearby thick disk stars has been used to investigate the existence of an age-metallicity relation (AMR) in the Galactic thick disk. The results indicate that that there is indeed an age-metallicity relation present in the thick disk. By dividing the stellar sample into sub-groups, separated by 0.1 dex in metallicity, we show that the median a

Izumi Hachisu, Mariko Kato, Taichi Kato

We have modeled the unusual orbital light curve of V1494 Aquilae (Nova Aquilae 1999 No.2) and found that such an unusual orbital light curve can be reproduced when there exist two-armed, spiral shocks on the accretion disk. V1494 Aql is a fast classical nova and found to be an eclipsing system with the orbital period of 0.1346138 days in the late phase of th

Graham P. Smith, Jean-Paul Kneib, Ian Smail, Pasquale Mazzotta

We present a comprehensive space-based study of ten X-ray luminous galaxy clusters (L_X>=8e44erg/s[0.1-2.4keV]) at z=0.2. Hubble Space Telescope observations reveal numerous gravitationally-lensed arcs for which we present four new spectroscopic redshifts, bringing the total to thirteen confirmed arcs in this cluster sample. We combine the multiple-image sys

Mark Walker, Don Melrose, Dan Stinebring, Chengmin Zhang

Pulsar dynamic spectra sometimes show organised interference patterns; these patterns have been shown to have power spectra which often take the form of parabolic arcs, or sequences of inverted parabolic arclets whose apexes themselves follow a parabolic locus. Here we consider the interpretation of these arc and arclet features. We give a statistical formul

Jacek Brodzki, Graham Niblo

Let Gamma be a discrete group satisfying the rapid decay property with respect to a length function which is conditionally negative. Then the reduced C*-algebra of Gamma has the metric approximation property. The central point of our proof is an observation that the proof of the same property for free groups due to Haagerup transfers directly to this more ge

Ragab M. Gad

We use the Einstein and Papapetrou energy-momentum complexes to calculate the energy and momentum densities of Weyl metric as well as Curzon metric. We show that these two different definitions of energy-momentum complexes do not provide the same energy density for Weyl metric, although they give the same momentum density. We show that, in the case of Curzon

Paul L. Schechter, Joachim Wambsganss, Geraint F. Lewis

It has been conjectured that the distribution of magnifications of a point source microlensed by a population of intervening point masses is independent of its mass spectrum. We present gedanken experiments that cast doubt on this conjecture and numerical simulations that show it to be false.

M. Csanad, T. Csorgo, B. Lorstad, A. Ster

Buda-Lund hydro model fits are compared to BRAHMS, PHENIX, PHOBOS and STAR data on identified particle spectra, two-particle Bose-Einstein or HBT correlations, charged particle pseudorapidity distributions and pseudorapidity as well as p_t dependent elliptic flow in sqrt(s_NN) = 130 and 200 GeV Au+Au collisions at RHIC. Preliminary results indicate that 7/8-

S. Sanna, G. Allodi, G. Concas, A. H. Hillier

We performed zero and transverse field MuSR experiments on a large number of YBa2Cu3O6+x samples. We detect coexistence of antiferro-type (AF) short range magnetism with superconductivity below T_f~10 K in compositions 0.37<x<0.39. Most muons experience local AF fields, even when SQUID detects a full SC volume fraction, which points to a local minimal interf

I. A. Dmitriev, A. D. Mirlin, D. G. Polyakov

We have analyzed the quasiclassical mechanism of magnetooscillations in the ac- and photoconductivity, related to non-Markovian dynamics of disorder-induced electron scattering. While the magnetooscillations in the photoconductivity are found to be weak, the effect manifests itself much more strongly in the ac conductivity, where it may easily dominate over

R. Aldrovandi, J. P. Beltran Almeida, J. G. Pereira

The infinite cosmological &#34;constant&#34; limit of the de Sitter solutions to Einstein&#39;s equation is studied. The corresponding spacetime is a singular, four-dimensional cone-space, transitive under proper conformal transformations, which constitutes a new example of maximally-symmetric spacetime. Grounded on its geometric and thermodynamic properties

Shigeki Sugimoto, Kazuyoshi Takahashi

We analyze the D9-D9bar system in type IIB string theory using Dp-brane probes. It is shown that the world-volume theory of the probe Dp-brane contains two-dimensional and four-dimensional QED in the cases with p=1 and p=3, respectively, and some applications of the realization of these well-studied quantum field theories are discussed. In particular, the tw

O. I. Kartavtsev, A. V. Malykh, V. P. Permyakov

Precise energies of rovibrational states of the exotic hydrogen-like molecule $(dtμ)Xee$ are of importance for $dtμ$ resonant formation, which is a key process in the muon-catalyzed fusion cycle. The effect of the internal structure and motion of the $dtμ$ quasi-nucleus on energy levels is studied using the three-body description of the $(dtμ)Xee$ molecule b

V. Tarasov, A. Varchenko

For the Lie algebra $gl_N$ we introduce a system of differential operators called the dynamical operators. We prove that the dynamical differential operators commute with the $gl_N$ rational quantized Knizhnik-Zamolodchikov difference operators. We describe the transformations of the dynamical operators under the natural action of the $gl_N$ Weyl group.

A. Eckart, F. K. Baganoff, M. Morris, M. W. Bautz

We report on the first simultaneous near-infrared/X-ray detection of the Sgr A* counterpart which is associated with the massive black hole at the center of the Milky Way. The observations have been carried out using the NACO adaptive optics (AO) instrument at the European Southern Observatory&#39;s Very Large Telescope and the ACIS-I instrument aboard the C

Alexander Lange

The paper aims at investigating perturbative quantum field theory (pQFT) in the approach of Epstein and Glaser (EG) and, in particular, its formulation in the language of graphs and Hopf algebras (HAs). Various HAs are encountered, each one associated with a special combination of physical concepts such as normalization, localization, pseudo-unitarity, causa

X. Leyronas, R. Combescot

We consider the possible mechanical instability of an ultracold Fermi gas due to the attractive interactions between fermions of different species. We investigate how the instability, predicted by a mean field calculation for an homogeneous system, is modified when the gas is trapped in a harmonic potential and quantum effects are included.

Stanislaw Mrowczynski, Anton Rebhan, Michael Strickland

We generalize the hard-thermal-loop effective action of the equilibrium quark-gluon plasma to a non-equilibrium system which is space-time homogeneous but for which the parton momentum distribution is anisotropic. We show that the manifestly gauge-invariant Braaten-Pisarski form of the effective action can be straightforwardly generalized and we verify that

Jaeuk U. Kim, Jari M. Kinaret, Mahn-Soo Choi

We consider a quantum wire double junction system with each wire segment described by a spinless Luttinger model, and study theoretically shot noise in this system in the sequential tunneling regime. We find that the non-equilibrium plasmonic excitations in the central wire segment give rise to qualitatively different behavior compared to the case with equil

T. Vuletic, T. Ivek, B. Korin-Hamzic, S. Tomic

The charge response of the ladders in Sr_14-xCa_xCu_24O_41 is characterized by dc resistivity, low frequency dielectric and optical spectroscopy in all three crystallographic directions. The collective charge-density wave screened mode is observed in the direction of the rungs for x=0, 3 and 6, in addition to the mode along the legs. For x=8 and 9, the charg

B. C. Allanach, S. F. King, D. A. J. Rayner

We make a first study of the phenomenological implications of twisted moduli in type I intersecting D5-brane models, focussing on the resulting predictions at the LHC using SOFTSUSY to estimate the Higgs and sparticle spectra. Twisted moduli can play an important role in giving a viable string realisation of sequestering in the limit where supersymmetry brea

A. Bialas, M. Jezabek

It is proposed that soft particle production in hadronic collisions is dominated by multiple gluon exchanges between partons from the colliding hadrons, followed by radiation of hadronic clusters from the coloured partons distributed uniformly in rapidity. This explains naturally two dominant features of the data: (a) The linear increase of rapidity spectra

Yue-Liang Wu, Yu-Feng Zhou

We discuss the time-dependent CP asymmetry of decay $B \to ϕK_S$ in an extension of the Standard Model with both two Higgs doublets and additional fourth-generation quarks. We show that although the Standard Model with two-Higgs-doublet and the Standard model with fourth generation quarks alone are not likely to largely change the effective $\sin 2 β$ from t

Yoshihisa Kitazawa, Yastoshi Takayama, Dan Tomino

We investigate the correlators of TrA_{mu}A_{nu} in matrix models on homogeneous spaces: S^2 and S^2 x S^2. Their expectation value is a good order parameter to measure the geometry of the space on which non-commutative gauge theory is realized. They also serve as the Wilson lines which carry the minimum momentum. We develop an efficient procedure to calcula

Hidenori Fukaya, Tetsuya Onogi

We study the scalar and pseudoscalar condensations and the eta^prime meson correlators of the two-flavor massive Schwinger model in the non-zero theta vacuum. Exploiting our new method which was developed to investigate topological effects in the previous work, we find that the pseudoscalar condensation is non-zero and there exists a long-range correlation o

Xiong-Jun Liu, Hui Jing, Mo-Lin Ge

We examine in detail the quantum memory technique for photons in a double $Λ$ atomic ensemble in this work. The novel application of the present technique to create two different quantum probe fields as well as entangled states of them is proposed. A larger zero-degeneracy class besides dark-state subspace is investigated and the adiabatic condition is confi

N. M. R. Peres, M. A. N. Araujo, Daniel Bozi

We discuss the magnetic phases of the Hubbard model for the honeycomb lattice both in two and three spatial dimensions. A ground state phase diagram is obtained depending on the interaction strength U and electronic density n. We find a first order phase transition between ferromagnetic regions where the spin is maximally polarized (Nagaoka ferromagnetism) a

Frederic Le Roux

For every Brouwer (ie planar, fixed point free, orientation preserving) homeomorphism h there exists a covering of the plane by translation domains, invariant simply-connected open subsets on which h is conjugate to an affine translation. We introduce a distance d_h on the plane that counts the minimal number of translation domains connecting a pair of point

Michael W. Feise, Yuri S. Kivshar

We study numerically, by means of the pseudospectral time-domain method, the unique features of imaging by a flat lens made of a left-handed metamaterial that possesses the property of negative refraction. We confirm the earlier finding that a left-handed flat lens can provide near-perfect imaging of a point source and a pair of point sources with clear evid

Hideo Kodama

The behaviour of stationary gravitational perturbations is studied for generalised static black holes in spacetimes of greater than three dimensions, using the formulation developed by the present author and Ishibashi. For the case in which the horizon has a spatial section with constant curvature, it is proved that irrespective of the value of the cosmologi

S. M. Kuzenko, I. N. McArthur

A closed-form expression is obtained for a holomorphic sector of the two-loop low-energy effective action for the N = 4 super Yang-Mills theory on its Coulomb branch where the gauge group SU(N) is spontaneously broken to SU(N-1) x U(1) and the dynamics is described by a single Abelian N = 2 vector multiplet. In the framework of the background-field method, t

S. Yonezawa, Y. Muraoka, Y. Matsushita, Z. Hiroi

We report the discovery of a new pyrochlore oxide superconductor RbOs2O6. The compound crystallizes in the same beta-pyrochlore structure as the recently discovered superconductor KOs2O6, where Os atoms form a corner-sharing tetrahedral network called the pyrochlore lattice with Rb or K atoms in the cage. Resistivity, magnetic susceptibility and specific hea

Atish Dabholkar, Ashik Iqubal, Joris Raeymaekers

Off-shell interactions for localized closed-string tachyons in C/Z_N superstring backgrounds are analyzed and a conjecture for the effective height of the tachyon potential is elaborated. At large N, some of the relevant tachyons are nearly massless and their interactions can be deduced from the S-matrix. The cubic interactions between these tachyons and the

Yuan Feng, Runyao Duan, Mingsheng Ying

We determine all $2\times 2$ quantum states that can serve as useful catalysts for a given probabilistic entanglement transformation, in the sense that they can increase the maximal transformation probability. When higher-dimensional catalysts are considered, a sufficient and necessary condition is derived under which a certain probabilistic transformation h

Ming Xiong Liu

We have developed new techniques to detect hadrons with the PHENIX muon spectrometers. This allows us to study the centrality dependent nuclear modification factor $R_{CP}$ with high $p_{T}$ hadrons in both forward (d direction) and backward (Au direction) rapidities, $1 < |η| < 2$, in dAu collisions at $\sqrt{s_{NN}} = 200 GeV$. Preliminary results show a s

Athanasios N. Petridis, Lawrence P. Staunton, Jon Vermedahl, Marshall Luban

Analytical solutions to the time-dependent Shrödinger equation in one dimension are developed for time-independent potentials, one consisting of an infinite wall and a repulsive delta function. An exact solution is obtained by means of a convolution of time-independent solutions spanning the given Hilbert space with appropriately chosen spectral functions. S

Sora Choi, Soojoon Lee, Dong Pyo Chi

We present a protocol for quantum cryptographic network consisting of a quantum network center and many users, in which any pair of parties with members chosen from the whole users on request can secure a quantum key distribution by help of the center. The protocol is based on the quantum authentication scheme given by Barnum et al. [Proc. 43rd IEEE Symp. FO

Akimasa Miyake

Stochastic local operations and classical communication (SLOCC), also called local filtering operations, are a convenient, useful set of quantum operations in grasping essential properties of entanglement. We give a quick overview about the characteristics of multipartite entanglement in terms of SLOCC, illustrating the 2-qubit and the rest (2 x 2 x n) quant

Shuichi Inokuchi, Yoshihiro Mizoguchi

In this paper, in order to investigate natural transformations from discrete CA to QCA, we introduce a new formulation of finite cyclic QCA and generalized notion of partitioned QCA. According to the formulations, we demonstrate the condition of local transition functions, which induce a global transition of well-formed QCA. Following the results, extending

H. -T. Elze

We study classical Hamiltonian systems in which the intrinsic proper time evolution parameter is related through a probability distribution to the physical time, which is assumed to be discrete. In this way, a physical clock with discrete states is introduced, which presently is still treated as decoupled from the system. This is motivated by the recent disc

M. E. Biagini

The design of an Interaction Region (IR) suitable to reach low values of the beta functions at the Interaction Point (IP) and a high collision frequency is a rather difficult task in a short ring as DAPHNE, where an upgrade of the peak luminosity to 10^34 cm-2s-1 is aimed [1]. In the following, general considerations on the design of such an IR are presented

Frank Wilczek

This is a short, light spirited account of how some possibly important science actually happened. It very much conflicts with Popper&#39;s contention that the key to scientific progress is falsification.

G. F. Gribakin, J. Ludlow

A many-body theory approach is developed for the problem of positron-atom scattering and annihilation. Strong electron-positron correlations are included non-perturbatively through the calculation of the electron-positron vertex function. It corresponds to the sum of an infinite series of ladder diagrams, and describes the physical effect of virtual positron

H. K. Avetissian, T. R. Hovhannisyan, G. F. Mkrtchian

In this paper we present the nonlinear quantum theory of X-Ray FEL in a wiggler. We present the solution of the Dirac equation in a space periodic strong magnetic field, which describes the quantum dynamics of a single electron in a wiggler. With the help of obtained wave function of an electron the self-consistent set of the Maxwell and relativistic quantum

Ruediger Vaas

Physicists in search of the foundation of the world: how tiny objects can create matter, energy and even space and time - and possibly countless other universes. -- This article is meant as an introduction into quantum geometry (loop quantum gravity) and string theory, written for the general audience. Partly, this article is also a conference report and rev

M. E. Biagini

The PEP-II luminosity upgrade foreseen for the next years requires an increased number of bunches and lower beta-y* with minor modifications to the present Interaction Region (IR2). When increasing the collision frequency the beams separation in IR2 can be an issue. A study of the effect of the parasitic crossings for both the head-on and horizontal crossing

J. Marciak-Kozlowska, M. Kozlowski

In this paper the possibility of the excitation of collective nuclear motion with attosecond laser pulses is investigated. Following our earlier results (Lasers in Engineering 11 (2001) p. 259) the hyperbolic heat transport for nuclear matter is formulated and solved. It is shown that in the vicinity of the 30 MeV excitation energy the recollided electrons c

Michael Martin Nieto

Open-source data exists, in widely scattered places, on photofission of the important nuclear isotopes ^{235}U and ^{239}Pu. This data is useful for studies aimed at detecting these materials at ports of entry. An introductory survey is given to access that data.

M. J. Tannenbaum

Small, but significant non-random fluctuations in event-by-event average $p_T$ have been observed in Au+Au collisions at $\sqrt{s_{NN}}=200$ GeV by the PHENIX collaboration at RHIC. These are consistent with being caused by correlations due to jets at large $p_T$, where the measured suppression must be included to reproduce the centrality dependence of the n

Hokky Situngkir

Democracy in a state is possibly a gain to have the government that represents the whole citizens. But the main element of the democratic system is the ability of the governmental functions in the state to act properly in order to gain the citizen wants. The simulation presented in this paper shows how the rule-making, rule-application, and rule-adjudication

Moubariz Z. Garaev, Florian Luca, Igor E. Shparlinski

We estimate the number of solutions of certain diagonal congruences involving factorials. We use these results to bound exponential sums with products of two factorials $n!m!$ and also derive asymptotic formulas for the number of solutions of various congruences with factorials. For example, we prove that the products of two factorials $n!m!$ with $\max\{n,m

Moubariz Z. Garaev, Florian Luca, Igor E. Shparlinski

We estimate character sums with n!, on average, and individually. These bounds are used to derive new results about various congruences modulo a prime p and obtain new information about the spacings between quadratic nonresidues modulo p. In particular, we show that there exists a positive integer $n\ll p^{1/2+ε}, such that n! is a primitive root modulo p. W

Martin Arkowitz, Robert F. Brown

The reduced Lefschetz number, that is, the Lefschetz number minus 1, is proved to be the unique integer-valued function L on selfmaps of compact polyhedra which is constant on homotopy classes such that (1) L(fg) = L(gf), for f:X -->Y and g:Y -->X; (2) if (f_1, f_2, f_3) is a map of a cofiber sequence into itself, then L(f_2) = L(f_1) + L(f_3); (3) L(f) = -

Dan Coman, Evgeny A. Poletsky

In this paper we obtain estimates for certain transcendence measures of an entire function $f$. Using these estimates, we prove Bernstein, doubling and Markov inequalities for a polynomial $P(z,w)$ in ${\Bbb C}^2$ along the graph of $f$. These inequalities provide, in turn, estimates for the number of zeros of the function $P(z,f(z))$ in the disk of radius $

Marcos Dajczer, Luis A. Florit, Ruy Tojeiro

We introduce the notion of weak reduciblity for Dupin submanifolds with arbitrary codimension. We give a complete characterization of all weakly reducible Dupin submanifolds, as a consequence of a general result on a broader class of Euclidean submanifolds. As a main application, we derive an explicit recursive procedure to generate all holonomic Dupin subma

Gabriel D. Carroll, David E Speyer

We construct a combinatorial model that is described by the cube recurrence, a nonlinear recurrence relation introduced by Propp, which generates families of Laurent polynomials indexed by points in $\mathbb{Z}^3$. In the process, we prove several conjectures of Propp and of Fomin and Zelevinsky, and we obtain a combinatorial interpretation for the terms of

Pierre Guillot

We use the Steenrod algebra to study $CH^*BG$, the mod $p$ Chow ring of the classifying space of $G$. We describe a localization property which relates a given $G$ to its elementary abelian subgroups, and we study a number of particular cases, namely symmetric groups and Chevalley groups. It turns out that the Chow rings of these groups are completely determ

Ronald Ortner, Wolfgang Woess

Let X be a locally finite, connected graph without vertices of degree 1. Non-backtracking random walk moves at each step with equal probability to one of the &#34;forward&#34; neighbours of the actual state, i.e., it does not go back along the preceding edge to the preceding state. This is not a Markov chain, but can be turned into a Markov chain whose state

Pierre Guillot

We compute the cobordism ring $MU^*(BG)\otimes \mathbb{F}_p$ when $G$ is a Chevalley group. In the particular case of the general linear group, we prove that it agrees with the Chow ring (as defined by Totaro).

Nicolas Roy

Nondegeneracy conditions need to be imposed in K.A.M. theorems to insure that the set of diophantine tori has a large measure. Although they are usually expressed in action coordinates, it is possible to give a geometrical formulation using the notion of regular completely integrable systems defined by a fibration of a symplectic manifold by lagrangian tori

Nicolas Roy

Given a fibration of a symplectic manifold by lagrangian tori, we show that each symplectic vector field splits into two parts : the first is Hamiltonian and the second is symplectic and preserves the fibration. We then show an application of this result in the study of the regular deformations of completely integrable systems.

Yael Fregier

We study non-trivial deformations of the natural imbedding of the Lie algebra $\fh_1$ of lower triangular matrices (the Heisenberg Lie algebra) into $gl(3,\mathbb{K})$, where $\mathbb{K}=\mathbb{R}$ or $|mathbb{C}$. Our first result is the calculation of the first cohomology space $H^1(\fh_1;gl(3,\mathbb{K}))$. We prove that there are no obstructions for int

Rikard Bögvad, Rolf Källström

We study, in the setting of algebraic varieties, finite-dimensional spaces of functions V that are invariant under a ring D^V of differential operators, and give conditions under which D^V acts irreducibly. We show how this problem, originally formulated in physics (Kamran-Milson-Olver), is related to the study of principal parts bundles and Weierstrass poin

N. Bergeron

Let $G$ be a connected semisimple group over ${\Bbb Q}$. Given a maximal compact subgroup $K\subset G({\Bbb R})$ such that $X=G({\Bbb R})/K$ is a Hermitian symmetric domain, and a convenient arithmetic subgroup $Γ\subset G({\Bbb Q})$, one constructs a (connected) Shimura variety $S=S(Γ)=Γ\backslash X$. If $H\subset G$ is a connected semisimple subgroup such

Laszlo Lempert, Ning Zhang

The loop space LP_1 of the Riemann sphere is an infinite dimensional complex manifold consisting of maps (loops) from S^1 to P_1 in some fixed C^k or Sobolev W^{k,p} space. In this paper we compute the Dolbeault cohomology groups H^{0,1}(LP_1).

Victor J. W. Guo, Jiang Zeng

Lin and Chang gave a generating function of convex polyominoes with an $m+1$ by $n+1$ minimal bounding rectangle. Gessel showed that their result implies that the number of such polyominoes is $$ \frac{m+n+mn}{m+n}{2m+2n\choose 2m}-\frac{2mn}{m+n}{m+n\choose m}^2. $$ We show that this result can be derived from some binomial coefficients identities related t

E. Glasner, B. Tsirelson, B. Weiss

Classical ergodic theory deals with measure (or measure class) preserving actions of locally compact groups on Lebesgue spaces. An important tool in this setting is a theorem of Mackey which provides spatial models for Boolean G-actions. We show that in full generality this theorem does not hold for actions of Polish groups. In particular there is no Borel m

Makoto Sakaguchi, Kentaroh Yoshida

We promote a study of D-branes of type IIB string on the AdS_5 x S^5 background. The possible D-branes preserving half of supersymmetries were classified up to and including the fourth order of fermionic variable þin our previous work [hep-th/0310228]. In this paper we show that our classification is still valid even at the full order of þ. This proof supple

R. Manvelyan, W. Ruehl

The higher spin interaction currents for the conformally coupled scalar in $AdS_{4}$ space for both regular and irregular boundary condition corresponding to the free and interacting critical point of the boundary O(N) sigma model are constructed. The explicit form of the linearized interaction of the scalar and spin two and four gauge fields in the $AdS_{D}

Hideo Kodama

The present status of the uniqueness and stability issue of black holes in four and higher dimensions is overviewed with focus on the perturbative analysis of this issue for static black holes in higher dimensions as well as for those in four dimensions with cosmological constant.