arXiv papers from October 2000

Lingling Wu

The domain wall fermion formulation exhibits full chiral symmetry for finite lattice spacing except for the effects of mixing between the domain walls. Close to the continuum limit these symmetry breaking effects should be described by a single residual mass. We determine this mass from the conservation law obeyed by the conserved axial current in quenched s

Yi-Fang Wang

We propose here a large homogeneous calorimeter as the next generation neutrino detector for $\nu$ factories and/or conventional $\nu$ beams. The active media is chosen to be water for obvious economical reasons. The \v Cerenkov light produced in water is sufficient to have good energy resolution, and the pattern recognition is realized by a modular water ta

J. L. Hewett, F. J. Petriello, T. G. Rizzo

Recent theoretical results have demonstrated that non-commutative geometries naturally appear within the context of string/M-theory. One consequence of this possibility is that QED takes on a non-abelian nature due to the introduction of 3- and 4-point functions. In addition, each QED vertex acquires a momentum dependent phase factor. We parameterize the eff

M. Drndic, C. S. Lee, R. M. Westervelt

Three-dimensional (3D) micro-electromagnets were developed to control particle motion in magnetic field landscapes in vacuum near a chip. Multiple layers of micron-scale conductors separated by transparent insulators create particle containers with deep, symmetric and time-dependent potentials, suitable for integration in quantum circuits. Single and coupled

D. Bullock, C. Frohman, J. Kania-Bartoszynska

We prove that the Kauffman bracket skein algebra of a cylinder over a surface with boundary, defined over complex numbers, is isomorphic to the observables of an appropriate lattice gauge field theory.

Ashwin Nayak, Ashvin Vishwanath

Motivated by the immense success of random walk and Markov chain methods in the design of classical algorithms, we consider_quantum_ walks on graphs. We analyse in detail the behaviour of unbiased quantum walk on the line, with the example of a typical walk, the ``Hadamard walk''. We show that after t time steps, the probability distribution on the line indu

Valeri A. Gritsenko, Viacheslav V. Nikulin

This is the announcement and partly the review of our results about classification of Lorentzian Kac-Moody algebras of the rank three. One of our results gives the classification of Lorentzian Kac-Moody algebras with denominator identity functions which are holomorphic reflective automorphic forms with respect to paramodular groups. Almost all of them were f

J. C. Osborn

The meron-cluster algorithm was previously used to extensively study the physics associated with the spontaneous breaking of a discrete symmetry. We recently discovered that a larger class of models with spontaneous breaking of continuous symmetries can also be simulated using the meron-cluster algorithm. Here we study one of these new models which belongs t

Yasufumi Yamashita, Kazuo Ueda

The ground-state properties of the spin-1 antiferromagnetic Heisenberg model on the corner-sharing tetrahedra, pyrochlore lattice, is investigated. By breaking up each spin into a pair of 1/2-spins, the problem is reduced to the equivalent one of the spin-1/2 tetrahedral network in analogy with the valence bond solid state in one dimension. The twofold degen

Dean Lee

We review the method of stochastic error correction which eliminates the truncation error associated with any subspace diagonalization. Monte Carlo sampling is used to compute the contribution of the remaining basis vectors not included in the initial diagonalization. The method is part of a new approach to computational quantum physics which combines both d

Dean Lee

We discuss a method called quasi-sparse eigenvector diagonalization which finds the most important basis vectors of the low energy eigenstates of a quantum Hamiltonian. It can operate using any basis, either orthogonal or non-orthogonal, and any sparse Hamiltonian, either Hermitian, non-Hermitian, finite-dimensional, or infinite-dimensional. The method is pa

Guido Berlin, J. Aliaga

In this paper we study a two-photon time-dependent Jaynes-Cummings model interacting with a Kerr-like medium. We assumed that the electromagnetic field is in different states such as coherent, squeezed vacuum and pair coherent, and that the atom is initially in the excited state. We studied the temporal evolution of the population of the excited level, and t

Chulwoo Jung, Robert G. Edwards, Xiangdong Ji, Valeriya Gadiyak

We study the effective quark mass induced by the finite separation of the domain walls in the domain-wall formulation of chiral fermion as the function of the size of the fifth dimension ($L_s$), the gauge coupling ($\beta$) and the physical volume ($V$). We measure the mass by calculating the small eigenvalues of the hermitian domain-wall Dirac operator ($H

C. Frohman, J. Kania-Bartoszynska

We describe a topological ribbon Hopf algebra whose elements are sequences of matrices. The algebra is a quantum version of U(sl_2).

Frederic C. Marton, Joel Ita, Ronald E. Cohen

The composition of the lower mantle can be investigated by examining densities and seismic velocities of compositional models as functions of depth. In order to do this it is necessary to know the volumes and thermoelastic properties of the compositional constituents under lower mantle conditions. We determined the thermal equation of state (EOS) of MgSiO3 p

M. Sako, S. M. Kahn, E. Behar, J. S. Kaastra

The luminous infrared-loud quasar IRAS 13349+2438 was observed with the XMM-Newton Observatory as part of the Performance Verification program. The spectrum obtained by the Reflection Grating Spectrometer (RGS) exhibits broad (v ~ 1400 km/s FWHM) absorption lines from highly ionized elements including hydrogen- and helium-like carbon, nitrogen, oxygen, and n

J. Cottam, S. M. Kahn, A. C. Brinkman, J. W. den Herder

We present initial results from observations of the low-mass X-ray binary EXO 0748-67 with the Reflection Grating Spectrometer on board the XMM-Newton Observatory. The spectra exhibit discrete structure due to absorption and emission from ionized neon, oxygen, and nitrogen. We use the quantitative constraints imposed by the spectral features to develop an em

D. O. Caldwell, R. N. Mohapatra, S. J. Yellin

Solar, atmospheric and LSND neutrino oscillation results require a light sterile neutrino, $\nu_B$, which can exist in the bulk of extra dimensions. Solar $\nu_e$, confined to the brane, can oscillate in the vacuum to the zero mode of $\nu_B$ and via successive MSW transitions to Kaluza-Klein states of $\nu_B$. This new way to fit solar data is provided by b

Cameron McA. Gordon, Ying-Qing Wu

We show that if a simple 3-manifold $M$ has two Dehn fillings at distance $\Delta \geq 4$, each of which contains an essential annulus, then $M$ is one of three specific 2-component link exteriors in $S^3$. One of these has such a pair of annular fillings with $\Delta = 5$, and the other two have pairs with $\Delta = 4$.

J. R. Peterson, F. B. S. Paerels, J. S. Kaastra, M. Arnaud

We present detailed spatially-resolved spectroscopy results of the observation of Abell 1835 using the European Photon Imaging Cameras (EPIC) and the Reflection Grating Spectrometers (RGS) on the XMM-Newton observatory. Abell 1835 is a luminous ($10^{46}$ ergs ${s}^{-1}$), medium redshift ($z=0.2523$), X-ray emitting cluster of galaxies. The observations sup

David L. Olmsted, Kedar Y. Hardikar, Rob Phillips

Atomistic computations of the Peierls stress in fcc metals are relatively scarce. By way of contrast, there are many more atomistic computations for bcc metals, as well as mixed discrete-continuum computations of the Peierls-Nabarro type for fcc metals. One of the reasons for this is the low Peierls stresses in fcc metals. Because atomistic computations of t

M. Carena, J. S. Conway, H. E. Haber, J. D. Hobbs

This report presents the theoretical analysis relevant for Higgs physics at the upgraded Tevatron collider and documents the Higgs Working Group simulations to estimate the discovery reach in Run 2 for the Standard Model and MSSM Higgs bosons. Based on a simple detector simulation, we have determined the integrated luminosity necessary to discover the SM Hig

Ph. de Forcrand, M. Pepe

We exhibit the connection between local gauge singularities in the Laplacian gauge and topological charge, which opens the possibility of studying instanton excitations without cooling. We describe our version of Laplacian gauge-fixing for SU(N).

Yi-Zhi Huang

For a finitely-generated vertex operator algebra of central charge c, a locally convex topological completion is constructed. We construct on the completion a structure of an algebra over the operad of the c/2-th power of the determinant line bundle over the moduli space of genus-zero Riemann surfaces with ordered analytically parametrized boundary component

A. Rebei, J. de Pablo

A new mean-field type theory is proposed to study order-disorder transitions (ODT) in block copolymers. The theory applies to both the weak segregation (WS) and the strong segregation (SS) regimes. A new energy functional is proposed without appealing to the random phase approximation (RPA). We find new terms unaccounted for within RPA. We work out in detail

Keivan G. Stassun, Robert D. Mathieu, Frederick J. Vrba, Tsevi Mazeh

We use mid-IR (primarily 10 $\mu$m) photometry as a diagnostic for the presence of disks with inner cavities among 32 pre-main sequence stars in Orion and Taurus-Auriga for which rotation periods are known and which do not show evidence for inner disks at near-IR wavelengths. Disks with inner cavities are predicted by magnetic disk-locking models that seek t

Alex Clark

Generalizing a construction of A. Weil, we introduce a topological invariant for flows on compact, connected, finite dimensional, abelian, topological groups. We calculate this invariant for some examples and compare the invariant with other flow invariants.

R. L. Graham, J. C. Lagarias, C. L. Mallows, A. R. Wilks

This paper gives $n$-dimensional analogues of the Apollonian circle packings in parts I and II. We work in the space $\sM_{\dd}^n$ of all $n$-dimensional oriented Descartes configurations parametrized in a coordinate system, ACC-coordinates, as those $(n+2) \times (n+2)$ real matrices $\bW$ with $\bW^T \bQ_{D,n} \bW = \bQ_{W,n}$ where $Q_{D,n} = x_1^2 +... +

Daniel Sanchez-Portal, Emilio Artacho, Javier Junquera, Alberto Garcia

We have applied first-principles density-functional calculations to the study of the energetics, and the elastic and electronic properties of monatomic wires of Au, Cu, K, and Ca in linear and a planar-zigzag geometries. For Cu and Au wires, the zigzag distortion is favorable even when the linear wire is stretched, but this is not observed for K and Ca wires

Renyue Cen, Greg L. Bryan

Hydrodynamic simulations of Lyman alpha clouds based on ab inito cosmological models have produced results that are in broad agreement with observations. However, further analyses have revealed that, with progressively higher numerical resolution, the median or cutoff line width of the simulated Lyman alpha clouds (i.e. the Doppler parameter) appears to conv

N. Mirabal, J. P. Halpern

In the error box of 3EG J1835+5918, the brightest as-yet unidentified EGRET source at intermediate Galactic latitude, we find a weak, ultrasoft X-ray source at energies E < 0.3 keV in the ROSAT All-Sky Survey. Deep optical imaging at the location of this source, as pinpointed by an observation with the ROSAT HRI, reveals a blank field to a limit of V > 25.2.

Daniel Sanchez-Portal, Emilio Artacho, J. I. Pascual, J. Gomez-Herrero

The adsorption of C60 on Si(111) has been studied by means of first-principles density functional calculations. A 2x2 adatom surface reconstruction was used to simulate the terraces of the 7x7 reconstruction. The structure of several possible adsorption configurations was optimized using the ab initio atomic forces, finding good candidates for two different

A. V. Kotikov, G. Parente

We investigate the Q^2 evolution of parton distributions at small x values, obtained in the case of flat initial conditions. The results are in excellent agreement with deep inelastic scattering experimental data from HERA.

G. Akemann, E. Kanzieper

The microscopic spectral eigenvalue correlations of QCD Dirac operators in the presence of dynamical fermions are calculated within the framework of Random Matrix Theory (RMT). Our approach treats the low--energy correlation functions of all three chiral symmetry breaking patterns (labeled by the Dyson index $\beta=1,2$ and 4) on the same footing, offering a

JLQCD Collaboration, S. Aoki, R. Burkhalter, M. Fukugita

We report on our study of light hadron spectrum and quark masses in QCD with two flavors of dynamical quarks. Simulations are made with the plaquette gauge action and the non-perturbatively $O(a)$ improved Wilson quark action. We simulate 5 sea qaurk masses corresponding to $m_{PS}/m_{V} \simeq 0.8$--0.6 at $\beta=5.2$ on $12^3 \times 48$, $16^3 \times 48$ a

Shao-Hsuan Chiu, T. K. Kuo

See math-ph/0205036 for an expanded version.

P. Busch

This is an essay review of the book by D. Home: "Conceptual Foundations of Quantum Physics: An Overview from Modern Perspectives" (New York: Plenum Press, 1997), xvii+386 pp., ISBN 0-306-45660-5.

P. Massey, K. DeGioia-Eastwood, E. Waterhouse

Here we examine 12 Galactic clusters and OB associations containing Wolf-Rayet stars (W-Rs) and/or Luminous Blue Variables (LBVs), in order to assess the progentor masses of these evolved massive stars. We find that in the Milky Way, early-type WN stars evolve from stars with masses as low as 20Mo. Some early-type WN stars are found in clusters with very hig

Lee Lindblom, Joel E. Tohline, Michele Vallisneri

The evolution of a neutron-star r-mode driven unstable by gravitational radiation (GR) is studied here using numerical solutions of the full non-linear fluid equations. The amplitude of the mode grows to order unity before strong shocks develop which quickly damp the mode. In this simulation the star loses about 40% of its initial angular momentum and 50% of

Ping Sun, D. Schmeltzer, A. R. Bishop

We use the two cut-off renormalization group (RG) method to study the spin-Peierls model in one-dimension for the entire phonon frequency range. We integrate out the phonon and solve the effective Fermion system via mean field and RG methods. We make use of the symmetry that the Neel, dimerization, and spin current order parameters form an SU(2) triplet base

Leonardo F. Guidi, Domingos H. U. Marchetti

We consider a quasilinear parabolic differential equation associated with the renormalization group transformation of the two-dimensional hierarchical Coulomb system in the limit as the size of the block L goes to 1. We show that the initial value problem is well defined in a suitable function space and the solution converges, as t goes to infinity, to one o

Anirvan Mayukh Sengupta, Partha Pratim Mitra

We study memoryless, discrete time, matrix channels with additive white Gaussian noise and input power constraints of the form $Y_i = \sum_j H_{ij} X_j + Z_i$, where $Y_i$ ,$X_j$ and $Z_i$ are complex, $i=1..m$, $j=1..n$, and $H$ is a complex $m\times n$ matrix with some degree of randomness in its entries. The additive Gaussian noise vector is assumed to ha

David Bessis

Empirical properties of generating systems for complex reflection groups and their braid groups have been observed by Orlik-Solomon and Brou\'e-Malle-Rouquier, using Shephard-Todd classification. We give a general existence result for presentations of braid groups, which partially explains and generalizes the known empirical properties. Our approach is invar

D. Schmeltzer

We show that the macroscopic current and charge can be formulated as a Quantum Mechanical zero mode problem. We find that the current is given by the velocity operator of a particle restricted to move around a circle. As an explicit example we investigate a Luttinger liquid of length $L$ which is perturbed by a time dependent impurity. Using the statistical

T. Abu-Zayyad, K. Belov, D. J. Bird, J. Boyer

We study the spectrum and average mass composition of cosmic rays with primary energies between 10^{17} eV and 10^{18} eV using a hybrid detector consisting of the High Resolution Fly's Eye (HiRes) prototype and the MIA muon array. Measurements have been made of the change in the depth of shower maximum as a function of energy. A complete Monte Carlo simulat

Vyacheslav M. Futorny, Duncan J. Melville, Alexander N. Grishkov

Let g be an untwisted affine Kac-Moody algebra and M_J(lambda) a Verma-type module for g with J-highest integral weight lambda. We construct quantum Verma-type modules M_J^q(lambda) over the quantum group U_q(g), investigate their properties and show that M_J^q(lambda) is a true quantum deformation of M_J(\l) in the sense that the weight structure is preserv

Christian Korff

A new set of exact scattering matrices in 1+1 dimensions is proposed by solving the bootstrap equations. Extending earlier constructions of colour valued scattering matrices this new set has its colour structure associated to non simply-laced Lie algebras. This in particular leads to a coupling of different affine Toda models whose fusing structure has to be

Boris Shoikhet

We extend the Kontsevich formality $L_\infty$-morphism $\U\colon T^\ndot_\poly(\R^d)\to\D^\ndot_\poly(\R^d)$ to an $L_\infty$-morphism of an $L_\infty$-modules over $T^\ndot_\poly(\R^d)$, $\hat \U\colon C_\ndot(A,A)\to\Omega^\ndot(\R^d)$, $A=C^\infty(\R^d)$. The construction of the map $\hat \U$ is given in Kontsevich-type integrals. The conjecture that such

Arash Mafi

We present a solution to the $\mu$ problem in an SO(10) supersymmetric grand unified (SUSY GUT) model with gauge mediated (GMSB) and D-term supersymmetry breaking. A Peccei-Quinn ({\bf PQ}) symmetry is broken at the messenger scale and enables the generation of the $\mu$ term. The invisible axion (Goldstone boson of {\bf PQ} symmetry breaking) is a cold dark

D. A. Brown, P. Danielewicz

We examine the possibility of extracting non-Gaussian sources from two-particle correlations in heavy-ion reactions. Non-Gaussian sources have been predicted in a variety of model calculations and may have been seen in various like-meson pair correlations. As a tool for this investigation, we have developed an improved imaging method that relies on a Basis s

M. Della Morte, R. Frezzotti, J. Heitger, S. Sint

We present a scaling study of lattice QCD with O(a) improved Wilson fermions and a chirally twisted mass term. In order to get precise results with a moderate computational effort, we have considered a system of physical size of 0.75^3 * 1.5 fm^4 with Schroedinger functional boundary conditions in the quenched approximation. Looking at meson observables in t

A. Chuvakin, J. Smith, B. W. Harris

Data for D*(2010) meson electroproduction in the range 10 < Q2 < 1350 GeV^2 has recently been presented by the ZEUS collaboration at HERA. We use these results together with previously published data for Q2 > 1 GeV^2 to test whether one can distinguish between different theoretical schemes for charm quark electroproduction. We find that up to the largest Q2

P. P. Kulish, N. Manojlovic

The eigenvectors of the osp(1|2) invariant Gaudin hamiltonians are found using explicitly constructed creation operators. Commutation relations between the creation operators and the generators of the loop superalgebra are calculated. The coordinate representation of the Bethe states is presented. The relation between the Bethe vectors and solutions to the K

F. Planas-Vilanova

In his paper "Residues of a Pfaff system relative to an invariant subscheme" in Trans. Amer. Math. Soc. 352, 2000, 4019-4035, F. Sancho de Salas defines the universal Koszul complex of a module $M$ over a sheaf of rings $\mathcal{O}$ as ${\rm Kos}(M)=\Lambda (M)\otimes_{\mathcal{O}}S(M)$, where $\Lambda (M)$ and $S(M)$ stand for the exterior and symmetric al

J. Bartels, H. Kowalski

We discuss HERA data on the high energy behavior of the total gamma*p cross section and on diffraction in deep inelastic scattering. We outline their novelty in comparison with diffraction in high energy hadron hadron scattering. As a physical picture, we propose an interpretation in terms of QCD radiation at small and large distances: a careful study of the

T. Umeda, R. Katayama, H. Matsufuru, O. Miyamura

We study hadron properties near the deconfining transition in the finite temperature lattice QCD. This paper focus on the heavy quarkonium states, such as $J/\psi$ meson. We compare the meson correlators above and below $T_c$ and discuss the possibility of the $c\bar{c}$ bound state by observing the wave function.

Anton Kapustin, Dmitri Orlov

A vertex algebra is an algebraic counterpart of a two-dimensional conformal field theory. We give a new definition of a vertex algebra which includes chiral algebras as a special case, but allows for fields which are neither meromorphic nor anti-meromorphic. To any complex torus equipped with a flat Kahler metric and a closed 2-form we associate an N=2 super

Bernard de Wit

We discuss toroidal compactifications of maximal supergravity coupled to an extended configuration of BPS states which transform consistently under the U-duality group. Under certain conditions this leads to theories that live in more than eleven spacetime dimensions, with maximal supersymmetry but only partial Lorentz invariance. We demonstrate certain feat

Joseph O'Rourke

It has recently been established by Below, De Loera, and Richter-Gebert that finding a minimum size (or even just a small) triangulation of a convex polyhedron is NP-complete. Their 3SAT-reduction proof is discussed.

Chun-Min Chang, A. H. Castro Neto, A. R. Bishop

We study the problem of one-dimensional (1D) Luttinger liquids in the insulating Mott-Hubbard phase in the presence of acoustic phonons in the semiclassical limit. We show that solitonic excitations can propagate freely in the system and the energy required to produce a soliton is reduced by a polaronic effect. We find a critical value of the electron-phonon

K. Lechner, P. A. Marchetti

We analyse spin and statistics of quantum dyon fields, i.e. fields carrying both electric and magnetic charge, in 3+1 space-time dimensions. It has been shown long time ago that, at the quantum mechanical level, a composite dyon made out of a magnetic pole of charge g and a particle of electric charge e possesses half-integral spin and fermionic statistics,

Marc Ruhlander, C. M. Soukoulis

The probability distribution of the conductance p(g) of disordered 2d and 3d systems is calculated by transfer matrix techniques. As expected, p(g) is Gaussian for extended states while for localized states it is log-normal. We find that at the mobility edge p(g) is highly asymmetric and universal.

Frank Sottile

We give a characteristic-free proof that general codimension-1 Schubert varieties meet transversally in a Grassmannian and in some related varieties. Thus the corresponding intersection numbers computed in the Chow (and quantum Chow) rings of these varieties are enumerative in all characteristics. We show that known transversality results do not apply to the

Ken Kashima

We consider the effective action of M-theory compactified on a S^1/Z_2 orbifold with R^2 interaction in the Gauss-Bonnet combination. We derive equations of motion with source terms arising from the Gauss-Bonnet terms and find the M2-brane solution up to order \kappa^{2/3}. It receives a correction which depends on the orbifold coordinate in the same form as

JLQCD Collaboration, N. Yamada, S. Aoki, R. Burkhalter

We present our recent results for the B-parameters, which parameterize the \Delta B=2 transition amplitudes. Calculations are made in quenched QCD at \beta=5.7, 5.9, and 6.1, using NRQCD for heavy quark and the $O(a)$-improved action for light quark. The operators are perturbatively renormalized including corrections of O(\alpha_s/am_Q). We examine scaling b

Merced Montesinos, Jose David Vergara

In this paper it is implemented how to make compatible the boundary conditions and the gauge fixing conditions for complex general relativity written in terms of Ashtekar variables using the Henneaux-Teitelboim-Vergara approach. Moreover, it is found that at first order in the gauge parameters, the Hamiltonian action is (on shell) fully gauge-invariant under

D. Becirevic, V. Lubicz, G. Martinelli, F. Mescia

We present the first lattice calculation of the matrix element of the electromagnetic operator <pi0|Q+|K0>, where Q+ = (Q_d e/16 pi^2)* (\bar s_L sigma{mu,nu} F{mu,nu} d_R + \bar s_R sigma{mu,nu} F{mu,nu} d_L). This matrix element plays an important role, since it contributes to enhance the CP violating part of the K_L -> pi0 e+ e- amplitude in supersymmetri

Daniel A. Stariolo

We show results of simulations of a weakly driven four dimensional Edwards- Anderson spin glass, which presents clear signatures of dynamical ultrametricity at low temperatures. The presence of a hierarchical organization of time scales is evident from the appearance of a triangular relation between correlations at three characteristic long times in the asym

F. Shoji

We formulate a stochastic gauge fixing method to study the gauge dependence of Abelian projection. In this method, one can change the gauge from the maximally Abelian one to no gauge fixing continuously. We have found that the linear part of the heavy quark potential from Abelian contribution depends little on the gauge parameter. Similar results have been o

Y. Levinson, O. Entin-Wohlman, P. Wolfle

We consider pumping through a small quantum dot separated from the leads by two point contacts, whose conductances, $G_{1}$ and $G_{2}$, serve as pumping parameters. When the dot is pincched, we find that there is a "resonance line" in the parameter plane $\{G_{1}, G_{2}\}$ along which the Fermi energy in the leads aligns with the energy of the quasi-bound s

Tomek Plewa, Ewald Mueller

Implementation details and test cases of a newly developed hydrodynamic code, AMRA, are presented. The numerical scheme exploits the adaptive mesh refinement technique coupled to modern high-resolution schemes which are suitable for relativistic and non-relativistic flows. Various physical processes are incorporated using the operator splitting approach, and

J. Sato, K. Tobe, T. Yanagida

We present a new constraint on a lepton mixing matrix $V$ from lepton-flavor violating (LFV) processes in supersymmetric standard models with massive neutrinos. Here, we assume Yukawa-coupling unification $f_{\nu 3}\simeq f_{\rm top}$, in which $\tau$-neutrino Yukawa coupling $f_{\nu 3}$ is unified into top-quark Yukawa coupling $f_{\rm top}$ at the unificat

Pushan Majumdar, Dong-Shin Shin

Recently Anishetty, Majumdar and Sharatchandra have proposed a way of characterizing topologically non-trivial configurations for 2+1-dimensional Yang-Mills theory in a local and manifestly gauge invariant manner. Here we develop criteria to locate such objects in lattice gauge theory and find them in numerical simulations.

A. Dumitru, J. Brachmann, E. S. Fraga, W. Greiner

A generic property of a first-order phase transition in equilibrium, and in the limit of large entropy per unit of conserved charge, is the smallness of the isentropic speed of sound in the ``mixed phase''. A specific prediction is that this should lead to a non-isotropic momentum distribution of nucleons in the reaction plane (for energies around 40 AGeV in

J. Vernet, R. A. E. Fosbury, M. Villar-Martin, M. H. Cohen

In classifying the ensemble of powerful extragalactic radio sources, considerable evidence has accumulated that radio galaxies and quasars are orientation-dependent manifestations of the same parent population: massive spheroidal galaxies containing correspondingly massive black holes. [...] In this study, we exploit the opportunity to eliminate the quasar g

Anvar R. Mavlyutov

We study the B-model chiral ring of Calabi-Yau hypersurfaces in Batyrev's mirror construction. The main result is an explicit description of a subring of the chiral ring of semiample regular (transversal to torus orbits) Calabi-Yau hypersurfaces. This subring includes the marginal operators and contains all information about the correlation functions used by

Y. G. Yi

An electron may interact with itself through the vacuum polarization induced in the vacuum electrons due to the electron.

Igor Bayak

It is shown in what way monomial group connects Abelian group Z^{n} and total linear group GL(n). It is shown that any subgroup of Abelian group Z^{n} induces subgroup of monomial group $S_{2}\wr S_n}$, which in its turn induces corresponding subgroup of GL_{n}(R).

M. Artuso, CLEO Collaboration

Using 13.7 fb^{-1} of data recorded by the CLEO detector at CESR, we investigate the spectrum of charmed baryons which decay into Lambda_c^+ pi^- pi^+ and are more massive than the Lambda_{c1} baryons. We find evidence for two new states: one is broad and has an invariant mass roughly 480 MeV above that of the Lambda_c^+; the other is narrow with an invarian

Gregory Leibon

In this paper a new connection between the discrete conformal geometry problem of disk pattern construction and the continuous conformal geometry problem of metric uniformization is presented. In a nutshell, we discuss how to construct disk patterns by optimizing an objective function, which turns out to be intimately related to hyperbolic volume. With the u

Karim A. Malik, D. Wands, D. H. Lyth, A. R. Liddle

We discuss the evolution of linear perturbations about a Friedmann-Robertson-Walker background metric, using only the local conservation of energy-momentum. We show that on sufficiently large scales the curvature perturbation on spatial hypersurfaces of uniform-density is constant when the non-adiabatic pressure perturbation is negligible. We clarify the con

Simon Hands, Istvan Montvay, Manfred Oevers, Luigi Scorzato

We study the global symmetries of SU(2) gauge theory with N flavors of staggered fermions in the presence of a chemical potential. We motivate the special interest of the case N=1 (staggered) with fermions in the adjoint representation of the gauge group. We present results from numerical simulations with both hybrid Monte Carlo and the Two-Step Multi-Bosoni

M. A. Barstow, Howard E. Bond, M. R. Burleigh, J. B. Holberg

We present initial results from a Hubble Space Telescope ultraviolet imaging survey of stars known to have hot white-dwarf companions which are unresolved from the ground. The hot companions, discovered through their EUV or UV emission, are hidden by the overwhelming brightnesses of the primary stars at visible wavelengths. Out of 17 targets observed, we hav

A. Rajantie, P. M. Saffin, E. J. Copeland

It has recently been suggested that the baryon washout problem of standard electroweak baryogenesis could be avoided if inflation ends at a low enough energy density and a parametric resonance transfers its energy repidly into the standard model fields. We present preliminary results of numerical simulations in a SU(2)xU(1) gauge-Higgs model in which this pr

Th. Boller, M. Gliozzi, G. Griffiths, S. Sembay

We report on the XMM-Newton observations of the BL Lac object MS 0737.9+7441 during the performance verification phase. A simple power-law fit provides an adequate description of the integrated spectrum in the 0.2-10 keV energy band. The photon index is slightly steeper in the EPIC pn data with 2.38+-0.01 compared to the EPIC MOS data (2.28+-0.01). The diffe

Henry E. Kandrup

This paper explores the phenomenon of energy relaxation for stars in a galaxy embedded in a high density environment that is subjected continually to perturbations reflecting the presence of other nearby galaxies and/or incoherent internal pulsations. The analysis is similar to earlier analyses of energy relaxation induced by binary encounters between nearby

Bert Schroer

In conformally invariant quantum field theories one encounters besides the standard DHR superselection theory based on spacelike (Einstein-causal) commutation relations and their Haag duality another timelike (''Huygens'') based superselection structure. Whereas the DHR theory based on spacelike causality of observables confirmed the Lagrangian internal symm

Th. Boller, R. Keil, J. Truemper, P. T. O'Brien

We have analyzed the timing properties of the Narrow-line Seyfert 1 galaxy Mrk 766 observed with XMM-Newton during the PV phase. The source intensity changes by a factor of 1.3 over the 29,000 second observation. If the soft excess is modeled by a black body component, as indicated by the EPIC pn data, the luminosity of the black body component scales with i

Eric Goles, Michel Morvan, Ha Duong Phan

In this paper, we study the dynamics of sand grains falling in sand piles. Usually sand piles are characterized by a decreasing integer partition and grain moves are described in terms of transitions between such partitions. We study here four main transition rules. The more classical one, introduced by Brylawski (1973) induces a lattice structure $L_B (n)$

Victor Kac, Jan Troost

We discuss the stability of vacua in two-dimensional gauge theory for any simple, simply connected gauge group. Making use of the representation of a vacuum in terms of a Wilson line at infinity, we determine which vacua are stable against pair production of heavy matter in the adjoint of the gauge group. By calculating correlators of Wilson loops, we reduce

S. Stoica, H. V. Klapdor-Kleingrothaus

Double-beta decay matrix elements (ME) for $^{76}Ge$ are calculated with different quasi random phase approximation (QRPA)-based methods. First, the ME for the two-neutrino mode are computed using two choices for the single particle (s.p.) basis: i) $2-4\hbar\omega$ full shells and ii) $3-4\hbar\omega$ full shells. When calculated with the renormalized QRPA

Ozay Gurtug, Mustafa Halilsoy

Single pulse of null dust and colliding null dusts both transform a regular horizon into a space-like singularity in the space of colliding waves. The local isometry between such space-times and black holes extrapolates these results to the realm of black holes. However, inclusion of particular scalar fields instead of null dusts creates null singularities r

Erwan Jahier

A program execution monitor is a program that collects and abstracts information about program executions. The "collect" operator is a high level, general purpose primitive which lets users implement their own monitors. "Collect" is built on top of the Mercury trace. In previous work, we have demonstrated how this operator can be used to efficiently collect

Daniel Grieser

R. B. Melrose's b-calculus provides a framework for dealing with problems of partial differential equations that arise in singular or degenerate geometric situations. This article is a somewhat informal short course introducing many of the basic ideas of this world, assuming little more than a basic analysis and manifold background. As examples, classical ps

Dmitrii S. Golubev, Andrei D. Zaikin

An interplay between charge discreteness, coherent scattering and Coulomb interaction yields nontrivial effects in quantum transport. We derive a real time effective action and an equivalent quantum Langevin equation for an arbitrary coherent scatterer and evaluate its current-voltage characteristics in the presence of interactions. Within our model, at larg

Umberto Straccia

In fuzzy propositional logic, to a proposition a partial truth in [0,1] is assigned. It is well known that under certain circumstances, fuzzy logic collapses to classical logic. In this paper, we will show that under dual conditions, fuzzy logic collapses to four-valued (relevance) logic, where propositions have truth-value true, false, unknown, or contradic

Charles Hellaby

We propose a method of testing source evolution theories that is independent of the effects of inhomogeneity, and thus complementary to other studies of evolution. It is suitable for large scale sky surveys, and the new generation of large telescopes. In an earlier paper it was shown that basic cosmological observations - luminosity versus redshift, area dis

Giampiero Esposito, Alexander Yu. Kamenshchik

A brief review is presented of motivations and results in one-loop supergravity on manifolds with boundary, whose consideration is suggested by quantum cosmology.

Yuri I. Izotov, Daniel Schaerer, Corinne Charbonnel

The similarity between observed velocity structures of Al III and singly ionized species in damped Lyman-alpha systems (DLAs) suggests the presence of ionized gas in the regions where most metal absorption lines are formed. A simplified model consisting of Region 1) a plane-parallel ionization bounded region illuminated by an internal radiation field, and Re

Mark Cropper, Silvia Zane, Gavin Ramsay, Frank Haberl

We model the spin pulse intensity and hardness ratio profiles of the isolated neutron star RXJ0720.4--3125 using XMM-Newton data. The observed variation is approximately sinusoidal with a peak-to-peak amplitude of 15%, and the hardness ratio is softest slightly before flux maximum. By using polar cap models we are able to derive maximum polar cap sizes and a