August 2001 arXiv papers — page 19

S. Pakuliak, S. Sergeev

The hierarchy of the classical nonlinear integrable equations associated with relativistic Toda chain model is considered. It is formulated for the N-th powers of the quantum operators of the corresponding quantum integrable models. Following the ideas of the paper hep-th/9606144 it is shown how one can obtain such a system from 2D Toda lattice system. The r

Thomas W. Mattman

We show that the SL(2,C)-character variety of the (-2,3,n) pretzel knot consists of two (respectively three) algebraic curves when 3 does not divide n (respectively 3 divides n) and give an explicit calculation of the Culler-Shalen seminorms of these curves. Using this calculation, we describe the fundamental polygon and Newton polygon for these knots and gi

E. B. Davies

We describe the spectrum of a non-self-adjoint elliptic system on a finite interval. Under certain conditions we find that the eigenvalues form a discrete set and converge asymptotically at infinity to one of several straight lines. The eigenfunctions need not generate a basis of the relevant Hilbert space, and the larger eigenvalues are extremely sensitive

Geoffrey Grimmett, Philipp Hiemer

Techniques of `dynamic renormalization', developed earlier for undirected percolation and the contact model, are adapted to the setting of directed percolation, thereby obtaining solutions of several problems for directed percolation on $Z^d$ where $d \ge 2$. The first new result is a type of uniqueness theorem: for every pair $x$ and $y$ of vertices whi

Jae-Kwan Shim

In this article, we address one of the questions raised by Marc Rieffel in his collection of questions on deformation quantization. The question is whether the $K$-groups remain the same under flabby strict deformation quantizations. By "deforming" the question slightly, we produce a negative answer to the question.

Lajos Molnar

Let H be a separable infinite dimensional complex Hilbert space. We prove that every continuous 2-local automorphism of the poset (that is, partially ordered set) of all idempotents on H is an automorphism. Similar results concerning the orthomodular poset of all projections and the Jordan ring of all selfadjoint operators on H without the assumption on cont

Lajos Molnar

Let H be a complex Hilbert space and denote by Bs(H) the set of all self-adjoint bounded linear operators on H. In this paper we describe the form of all bijective maps (no linearity or continuity is assumed) on Bs(H) which preserve the usual order in both directions.

Lajos Molnar

Jordan isomorphisms of rings are defined by two equations. The first one is the equation of additivity while the second one concerns multiplicativity with respect to the so-called Jordan product. In this paper we present results showing that on standard operator algebras over spaces with dimension at least 2, the bijective solutions of that second equation a

Felix Cabello Sanchez, Lajos Molnar

We investigate the reflexivity of the isometry group and the automorphism group of some important metric linear spaces and algebras. The paper consists of the following sections: 1. Preliminaries. 2. Sequence spaces. 3. Spaces of measurable functions. 4. Hardy spaces. 5. Banach algebras of holomorphic functions. 6. Frechet algebras of holomorphic functions.

Lajos Molnar

In this paper we characterize the automorphisms of Hilbert space effect algebras by means of their preserving properties which concern certain relations and quantities appearing in quantum measurement theory.

Dinakar Ramakrishnan, Song Wang

The main objects of study in this article are two classes of Rankin-Selberg L-unctions, namely L(s, f \times g) and L(s, sym^2(g) \times sym^2(g)), where f, g are newforms, holomorphic or of Maass type, on the upper half plane, and sym^2(g) denotes the symmetric square lift of g to GL(3). We prove that in general, i.e., when these L-functions are not divisib

Siddhartha Gadgil

We relate the Andrews-Curtis conjecture to the triviality problem for balanced presentations of groups using algorithms from 3-manifold topology. Implementing this algorithm could lead to counterexamples to the Andrews-Curtis conjecture.

Yuri Berest, George Wilson

Let R be the set of isomorphism classes of ideals in the Weyl algebra $A=A_{1}$, and let C be the set of isomorphism classes of triples (V; X, Y), where V is a finite-dimensional (complex) vector space, and X, Y are endomorphisms of V such that [X,Y]+I has rank 1. Following a suggestion of L. Le Bruyn, we define a map $θ: R \to C$ by appropriately extending

I. Klich, A. Mann, M. Revzen

We consider the Casimir energy of a thick dielectric-diamagnetic shell under a uniform velocity light condition, as a function of the radii and the permeabilities. We show that there is a range of parameters in which the stress on the outer shell is inward, and a range where the stress on the outer shell is outward. We examine the possibility of obtaining an

John F. Tighe

We investigate the convergence of the derivative expansion of the exact renormalisation group, by using it to compute the beta function of scalar theory. We demonstrate that the derivative expansion of the Polchinski flow equation converges at one loop for certain fast falling smooth cutoffs. The derivative expansion of the Legendre flow equation trivially c

Wang-Chang Su

The gauge equivalent formulation of the Faddeev-Skyrme model is used for the study of the quantum theory. The rotational quantum excitations around the soliton solution of Hopf number unity are investigated by the method of collective coordinates. The quantum Hamiltonian of the system is found to coincide with the Hamiltonian of a symmetrical top rotating in

I. Martin, A. Restuccia

In built noncommutativity of supermembranes with central charges in eleven dimensions is disclosed. This result is used to construct an action for a noncommutative supermembrane where interesting topological terms appear. In order to do so, we first set up a global formulation for noncommutative Yang Mills theory over general symplectic manifolds. We make th

Zhang Benwei, Hou Defu, Li Jiarong

We investigate the self-consistency condition (SCC) of mean-field theory in Walecka model and find that the solutions of the SCC are multiple at high temperature and chemical potential. Using the effective Lagrangian approach, we study medium effects on the $ω$ meson mass by taking into account of vacuum effects. We show that the $ω$ meson mass decreases wit

R. Arnowitt, B. Dutta, B. Hu, Y. Santoso

The SUSY contribution to the muon magnetic moment anomaly, a_mu^SUGRA, and the electron electric dipole moment, d_e, is discussed within the framework of a modified mSUGRA model where the magnitudes of the soft breaking masses are universal, but arbitrary phases are allowed. It is shown analytically how the cancellation mechanism can allow for large phases (

Xavier Calmet

The leptons are viewed as composite objects, exhibiting anomalous magnetic moments and anomalous flavor-changing transition moments. The decay μ\to e γis expected to occur with a branching ratio of the same order as the present experimental limit. The first order QED radiative correction is considered.

Nicola Bianchi, Rainer Jakob

The contributions to the Spin Physics WG are summarized. Several new experimental results and plans for new measurements have been reported. An improved theoretical understanding of the most recent hot topics in spin physics has been discussed by many authors especially in the new fields of the transversity and generalized parton distributions.

V. A. Korotkov, W. -D. Nowak

Prospects for future measurements of Deeply Virtual Compton Scattering at HERMES are studied using different simple models for parameterizations of generalized parton distributions (GPDs). Measurements of the lepton charge and lepton beam helicity asymmetry will yield important input for theoretical models towards the future extraction of GPDs.

N. N. Nikolaev

Virtual photons have both the transverse and longitudinal polarization. In the inclusive DIS the impact of longitudinal photons, quantified by R=sigmaL/\igmaT sim 0.2, is marginal, but in diffractive DIS with excitation of small mass hadronic states or exclusive diffraction into vector mesons, QCD predicts R >> 1 in agreement with the experiment. After a bri

UKQCD Collaboration, A. Hart, M. Teper

We study the topological susceptibility, chi, in QCD with two quark flavours using the lattice field configurations recently produced by the UKQCD collaboration. We find clear evidence for the expected suppression at small quark mass, and examine the variation of chi with this mass. The resulting estimate of the pion decay constant, f_pi = 105 +/- 5 +18/-10

D0 Collaboration, V. M. Abazov

We have performed a search for scalar top quark (stop) pair production in the inclusive electron-muon-missing transverse energy final state, using a sample of $p \bar{p}$ events corresponding to 108.3 pb$^{-1}$ of data collected with the DØdetector at Fermilab. The search is done in the framework of the minimal supersymmetric standard model assuming that the

Sergio M. C. V. Goncalves

We study the curvature strength and visibility of the central singularity arising in Tolman-Bondi-de Sitter collapse. We find that the singularity is visible and Tipler strong along an infinite number of timelike geodesics, independently of the initial data, and thus stable against perturbations of the latter.

Gerard Clement, Sean A. Hayward

We show that the black hole perturbations of the Hayward static solution to the massless Einstein-Klein-Gordon equations are actually gauge artifacts resulting from the linearization of a coordinate transformation.

Ana Laura Garcia-Perciante, Alfredo Sandoval-Villalbazo, L. S. Garcia-Colin

Maxwell's equations can be obtained in generalized coordinates by considering the electromagnetic field as an external agent. The work here presented shows how to obtain the electrodynamics for a charged particle in generalized coordinates eliminating the concept of external force. Based on Kaluza's formalism, the one here presented extends the 5x5 m

Ioannis Kouletsis

The incompatibility between the treatment of time in the classical and in the quantum theory results in the so-called problem of time in canonical quantum gravity. For this reason, attempts have been made to devise algorithms of quantization which accomodate the covariance of the classical theory from the outset. One of the most prominent of these attempts i

Filippo Menczer

The latest generation of Web search tools is beginning to exploit hypertext link information to improve ranking\cite{Brin98,Kleinberg98} and crawling\cite{Menczer00,Ben-Shaul99etal,Chakrabarti99} algorithms. The hidden assumption behind such approaches, a correlation between the graph structure of the Web and its content, has not been tested explicitly despi

R. B. Pandey, J. F. Gettrust, D. Stauffer

The interacting lattice gas model is used to simulate fluid flow through an open percolating porous medium with the fluid entering at the source-end and leaving from the opposite end. The shape of the steady-state concentration profile and therefore the gradient field depends on the is found to scale with the porosity according to porosity p. The root mean s

Paul E. Lammert, Daniel S. Rokhsar

It has been suggested that the ``pseudogap'' regime in cuprate superconductors, extending up to hudreds of degrees into the normal phase, reflects an incoherent d-wave pairing, with local superconducting order coherent over a finite length scale $ξ$, insufficient to establish superconductivity. We calculate the single-particle spectral density in suc

T. F. Nagy, P. M. Duxbury

We present large scale simulations of the diffusion constant $D$ of a random composite consisting of aligned platelets with aspect ratio $a/b>>1$ in a matrix (with diffusion constant $D_0$) and find that $D/D_0 = 1/(1+ c_1 x + c_2 x^2)$, where $x= a v_f/b$ and $v_f$ is the platelet volume fraction. We demonstrate that for large aspect ratio platelets the pai

Baruch Horovitz, Pierre Le Doussal

Using an exact mapping to disordered Coulomb gases, we introduce a novel method to study two dimensional Dirac fermions with quenched disorder in two dimensions which allows to treat non perturbative freezing phenomena. For purely random gauge disorder it is known that the exact zero energy eigenstate exhibits a freezing-like transition at a threshold value

Cristiano L. Dias, Laurent J. Lewis, S. Roorda

We have used tight-binding molecular-dynamics simulations to investigate the role of point defects (vacancies and interstitials) on structural relaxation in amorphous silicon. Our calculations give unambiguous evidence that point defects can be defined in the amorphous solid, showing up as anomalies in the valence-charge/Voronoi-volume relation. The changes

M. Jarrell, Th. Maier, C. Huscroft, S. Moukouri

We present the algorithmic details of the dynamical cluster approximation (DCA), with a quantum Monte Carlo (QMC) method used to solve the effective cluster problem. The DCA is a fully-causal approach which systematically restores non-local correlations to the dynamical mean field approximation (DMFA) while preserving the lattice symmetries. The DCA becomes

Z. Hu, M. Knupfer, M. Kielwein, U. K. Roessler

A strong anisotropic distribution of the holes in Ni 3d and O 2p orbitals is observed in the polarization dependent O1s and Ni2p3/2 x-ray absorption spectroscopy of the linear-chain nickelate Y1-xCaxBaNiO5 (x = 0, 0.05, 0.1, 0.2), which demonstrates the one-dimensional nature of the electronic state in these compounds. Furthermore, the additional holes intro

Z. Hu, S. -L. Drechsler, J. Malek, H. Rosner

We present a joint experimental and theoretical study of the electronic structure of the cuprate chain systems A_(1-x)CuO_2 (A=Ca,Sr,Ba), as measured using O-K and Cu-L_3 x-ray absorption spectroscopy. The doping-dependent behaviour in these systems is radically different to that in conventional 2D cuprate networks formed from corner sharing CuO_4 plaquettes

Jiri Hoogland, Dimitri Neumann, Michel Vellekoop

It is a well known fact that local scale invariance plays a fundamental role in the theory of derivative pricing. Specific applications of this principle have been used quite often under the name of `change of numeraire', but in recent work it was shown that when invoked as a fundamental first principle, it provides a powerful alternative method for the

S. Pleutin, A. A. Ovchinnikov

The possibility for carbon materials such as activated carbon fibers or graphite ribbons, to support edge-states could change drastically their magnetic properties. The purpose of this work is to propose a novel way to identify the existence of those states by considering the behaviour of the static electric polarizability under a perpendicular magnetic fiel

Guang-Ming Zhang, Shun-Qing Shen

We consider a superexchange Hamiltonian, $H=-\sum_{<i,j>}(2{\bf S}_i\cdot {\bf S}_j-\frac 12)(2{\bf T}_i\cdot {\bf T}_j-\frac 12)$, which describes systems with orbital degeneracy and strong electron-phonon coupling in the limit of large on-site repulsion. In an SU(4) Schwinger boson representation, a reduced spin-orbital interaction is derived {\it exactly}

R. Giraud, W. Wernsdorfer, A. M. Tkachuk, D. Mailly

Strong hyperfine coupling in a 0.2% Holmium doped LiYF_4 single crystal induces staircaselike hysteresis loops of the magnetization at very low temperatures. The field sweep rate dependence of hysteresis loops allows the study of two different regimes in the magnetic relaxation of these weakly coupled magnetic moments. At slow field sweep rates, quantum tunn

S. Pleutin, A. A. Ovchinnikov

The static polarizability of cylindrical systems is shown to have a strong dependence on a uniform magnetic field applied parallel to the tube axis. This dependence is demonstrated by performing exact numerical diagonalizations of simple cylinders (rolled square lattices), armchair and zig-zag carbon nanotubes (rolled honeycomb lattices) for different electr

M. Andersson, J. C. Cuevas, M. Fogelstrom

The coupling of two s-wave superconductors through a small magnetic dot is discussed. Assuming that the dot charging energy is small compared to the superconducting gap, $E_c\ll Δ$, and that the moment of the dot is classical, we develop a simple theory of transport through the dot. The presence of the magnetic dot will position Andreev bound states within t

H. Fukazawa, R. G. Melko, R. Higashinaka, Y. Maeno

We report magnetization and ac susceptibility of single crystals of the spin ice compound Dy2Ti2O7. Saturated moments at 1.8 K along the charasteristic axes [100] and [110] agree with the expected values for an effective ferromagnetic nearest-neighbor Ising pyrochlore with local <111> anisotropy, where each magnetic moment is constrained to obey the `ice-rul

T. Adachi, T. Noji, Y. Koike

We have attempted the crystal growth by the traveling-solvent floating-zone (TSFZ) method of La_{2-x}Ba_xCuO_4 with x~1/8, where the superconductivity is strongly suppressed. Under flowing O_2-gas of a high pressure (4 bars), we have succeeded in growing single crystals of x=0.11 with 5 mm in diameter and 20 mm in length. It has been found that both in-plane

S. S. Indrakanti, V. F. Nesterenko, M. B. Maple, N. A. Frederick

Two different hot isostatic pressing cycles (HIPing) were investigated to synthesize bulk MgB2 samples: a &#34;standard&#34; cycle where a low vessel pressure is maintained while heating to the process temperature with a subsequent simultaneous pressure and temperature decrease and a new method - dense material cooling under pressure (DMCUP). The latter meth

Dennis Zaritsky, Amy E. Nelson, Luc Simard, Anthony H. Gonzalez

We present our study of the evolution of brightest cluster galaxies based on data from the Las Campanas Distant Cluster Survey (Gonzalez et al. 2001) and HST optical and IR imaging. We briefly discuss the technique that enabled us to use short (~ 3 min) exposures and a small (1m) telescope to efficiently survey about 130 sq. deg. of sky for high-z galaxy clu

G. G. Pavlov, D. Sanwal, B. Kiziltan, G. P. Garmire

The central region of the recently discovered supernova remnant RX J0852.0-4622 was observed with the ACIS detector aboard the Chandra X-ray Observatory. We found only one relatively bright source, about 4&#39; north of the SNR center, with a flux of $\sim 2\times 10^{-12}$ erg s$^{-1}$ cm$^{-2}$ in the 0.5--10 keV band. The position of this point-like sourc

Claes Fransson, Roger A. Chevalier, Alexei V. Filippenko, Bruno Leibundgut

Optical and ultraviolet observations of the Type IIn supernova 1995N at epochs between 321 and 1799 days after the explosion show three distinct velocity components. The narrow lines come from circumstellar gas and show both low and high ionization. This component has a low filling factor, and is photoionized by X-rays from the shock. The intermediate compon

Gary Steigman

In the framework of the standard, hot big bang cosmological model the dynamics of the early evolution of the universe is controlled by the energy density of relativistic particles, among which neutrinos play an important role. In equilibrium, the energy density contributed by one flavor of relativistic neutrinos is 7/8 of that of the cosmic background radiat

David B. Cline, Hanguo Wang, Y. Seo

We present a concept of a one ton two-phase liquid Xenon detector based on the concept of the ZEPLIN II detector currently under construction by a UCLA/Torino/UKDM team. The ZEPLIN II detector may be installed in the Boulby laboratory early in 2002. The one ton detector design will benefit from the initial operations of ZEPLIN II.

Daniel B. Nestor, Sandhya M. Rao, David A. Turnshek, Eric Monier

Images of five QSO fields containing six damped Lyman alpha (DLA) systems at redshifts 0.09<z<0.53 are presented. Identifications for the DLA galaxies giving rise to the DLA systems are made. The observed and modeled characteristics of the DLA galaxies are discussed. The DLA galaxies have impact parameters ranging from < 4 kpc to \approx 34 kpc and luminosit

Tomonori Totani, Yuzuru Yoshii, Fumihide Iwamuro, Toshinori Maihara

We report observational analyses and theoretical interpretations of unusually red galaxies in the Subaru Deep Field (SDF). A careful analysis of the SDF data revealed a population with unusually red near-infrared (NIR) colors of J - K >~ 3-4, with higher confidence than the previous SDF result. Their surface number density drastically increases at K >~ 22 an

David A. Turnshek, Sandhya M. Rao, Daniel B. Nestor

We compare the properties of a sample of local (z=0) gas-rich galaxies studied in 21 cm emission to a sample of 13 low-redshift (z < 1) damped Lyman alpha (DLA) galaxies identified as the counterparts of low-redshift DLA systems found in QSO absorption-line surveys. This absorption-selected sample has average redshift <z> = 0.5. We find that many of the prop

Sandhya M. Rao, David A. Turnshek

We discuss our recent results on the statistical properties of damped Lyman alpha systems (DLAs) at low redshift (z<1.65) (Rao & Turnshek 2000). Contrary to expectations, we found that the cosmological neutral gas mass density as traced by DLAs, $Ω_{DLA}$, does not evolve from redshifts $z \approx 4$ to $z \approx 0.5$ and that extrapolation to z=0 results i

T. Richtler, B. Dirsch, D. Geisler, K. Gebhardt

We performed spectroscopy of globular clusters associated with NGC 1399 and measured radial velocities of more than 400 clusters, the largest sample ever obtained for dynamical studies. In this progress report, we present the sample and the first preliminary results. Red and blue clusters have slightly different velocity dispersions in accordance with their

J. M. Torrejon, A. Orr

We present a BeppoSAX survey of five Be/X-ray binary candidates. We report on the identification of two of them, HD 110432 and HD 141926, as low luminosity Be/X-ray binaries. For HD 110432 we report on the detection of a pulsation period of ~14 ks. Because the luminosity of these sources is low and their spectra do not require non-thermal emission models, th

A. Cimatti

The results and the present limits of the observations of high-z ellipticals are discussed in the framework of VLT imminent and future instruments.

Y. N. Fu, J. H. Huang, Z. G. Deng

The dynamical evolution of super star clusters (SSCs) moving in the background of dark matter halo has been investigated as a possible event causing the observed correlation between the mass of galactic bulge, $M_{bulge}$, and the mass of its central black hole, $M_{BH}$. The involved physical processes are the sinking of SSCs due to the dynamical friction,

Takaaki Takeda, Shigeru Ida

We numerically calculated angular momentum transfer processes in a dense particulate disk within Roche limit by global $N$-body simulations, up to $N=10^5$, for parameters corresponding to a protolunar disk generated by a giant impact on a proto-Earth. In the simulations, both self-gravity and inelastic physical collisions are included. We first formalized e

Alin Panaitescu, Pawan Kumar, Ramesh Narayan

If the efficiency for producing $γ$-rays is the same in short duration ($\siml 2$ s) Gamma-Ray Bursts (GRBs) as in long duration GRBs, then the average kinetic energy of short GRBs must be $\sim 20$ times less than that of long GRBs. Assuming further that the relativistic shocks in short and long duration GRBs have similar parameters, we show that the afterg

D. Lutz, J. S. Dunlop, O. Almaini, P. Andreani

The IRAM Plateau de Bure mm interferometer and deep K-band imaging have been used to identify the brightest submm source detected in the Lockman field of the UK 8mJy SCUBA survey. The near infrared counterpart is an extended (20-30kpc), clumpy, and extremely red object. The spectral energy distribution suggests it to be a dusty star forming object at a redsh

Simon Morris, Robert Content, Ray Sharples, Richard Bower

We describe an instrument concept that will provide simultaneous spectra for a million spatial samples on the sky. With the proposed field of view and spectral resolution, it will be able to measure redshifts and line strengths for around 2-4000 z~3-7 galaxies in a 16 night campaign. The main science driver is to obtain a complete census of the star formatio

Simon L. Morris, Buell Jannuzi, Ray Weymann

We review the ongoing debate about the relationship between low redshift Lyman Alpha absorbers and luminous galaxies. In particular, we discuss the difficulty of `assigning&#39; a particular absorber to a particular galaxy, and consider methods of circumventing this problem. We also provide a status report on an ongoing project collecting more data to addres

J. Patrick Henry

Whether the X-ray luminosities of clusters of galaxies evolve has been a contentious issue for over ten years. However, the data available to address this issue have improved dramatically as cluster surveys from the ROSAT archive near completion. There are now three samples of nearby clusters and seven distant cluster samples. We present a uniform analysis o

Yoshiaki Taniguchi, Youichi Ohyama, Takashi Murayama, Michitoshi Yoshida

We present new optical spectroscopy of the high-redshift powerful radio galaxy MRC 0406$-$244 at redshift of 2.429. We find that the two extensions toward NW and SE probed in the rest-frame ultraviolet image are heated mainly by the nonthermal continuum of the active galactic nucleus. However, each extension shows a shell-like morphology, suggesting that the

Robert E. Rutledge, Lars Bildsten, Edward F. Brown, George G. Pavlov

(Abridged). The type-I X-ray bursting low mass X-ray binary KS 1731-260 was recently detected for the first time in quiescence by Wijnands et al., following an approximately 13 yr outburst which ended in Feb 2001. Unlike all other known transient neutron stars, the duration of this recent outburst is as long as the thermal diffusion time of the crust. The la

N. Manset, P. Bastien

We present numerical simulations of the periodic polarimetric variations produced by a binary star placed at the center of an empty spherical cavity inside a circumbinary ellipsoidal and optically thin envelope made of dust grains. Mie single-scattering is considered along with pre- and post-scattering extinction factors which produce a time-varying optical

B. Aubert

We present the results of searches for B decays to charmless two-body final states containing $η^\prime$ or $ω$ mesons, based on 20.7 fb$^{-1}$ of data collected with the BABAR detector. We find the branching fractions ${\cal B}(B^+\toη^\prime K^+) = (70\pm 8\pm 5)\times 10^{-6}$, ${\cal B}(B^0\toη^\prime K^0) = (42^{+13}_{-11}\pm 4)\times 10^{-6}$, and ${\c

Luis M. A. Bettencourt, Greg J. Stephens

Using both analytical arguments and detailed numerical evidence we show that the first order transition in the type-I 2D Abelian Higgs model can be understood in terms of the statistical mechanics of vortices, which behave in this regime as an ensemble of attractive particles. The well-known instabilities of such ensembles are shown to be connected to the pr

Lawrence Hall, Yasunori Nomura, Takemichi Okui, David Smith

We construct supersymmetric models of SO(10) unification in which the gauge symmetry is broken by orbifold compactification. We find that using boundary conditions to break the gauge symmetry down to $SU(3)_C \otimes SU(2)_L \otimes U(1)_Y \otimes U(1)_X$ without leaving unwanted massless states requires at least two extra dimensions, motivating us to work w

C. J. Horowitz

The neutrino driven wind during a core collapse supernova is an attractive site for r-process nucleosynthesis. The electron fraction $Y_e$ in the wind depends on observable neutrino energies and luminosities. The mean antineutrino energy is limited by supernova SN1987A data while lepton number conservation constrains the ratio of antineutrino to neutrino lum

Carl H. Albright, S. Geer

Within the framework of an SO(10) GUT model that can accommodate both the atmospheric and the LMA solar neutrino mixing solutions, we present explicit predictions for the neutrino oscillation parameters \sin^2 2θ_{13}, \sin^2 2θ_{12}, \sin^2 2θ_{23}, and Δm^2_{21}. Precise measurements of \sin^2 2θ_{12} and Δm^2_{21} by KamLAND can be used to precisely deter

E. N. Archibald, J. S. Dunlop, R. Jimenez, A. C. S. Friaca

We use a simple model of spheroid formation to explore the relationship between the creation of stars and dust in a massive proto galaxy and the growth of its central black hole. This model predicts that sub-mm luminosity peaks after only ~ 0.2 Gyr. However, without a very massive seed black hole, Eddington-limited growth means that a black hole mass of 10^9

Ranjan Mukhopadhyay, Gerald H. W. Lim, Michael Wortis

We study the shapes of human red blood cells using continuum mechanics. In particular, we model the crenated, echinocytic shapes and show how they may arise from a competition between the bending energy of the plasma membrane and the stretching/shear elastic energies of the membrane skeleton. In contrast to earlier work, we calculate spicule shapes exactly b

J. Scott Carter, Mohamed Elhamdadi, Masahico Saito

The quandle homology theory is generalized to the case when the coefficient groups admit the structure of Alexander quandles, by including an action of the infinite cyclic group in the boundary operator. Theories of Alexander extensions of quandles in relation to low dimensional cocycles are developed in parallel to group extension theories for group cocycle

L. Giusti, G. C. Rossi, M. Testa, G. Veneziano

We show how it is possible to give a precise and unambiguous implementation of the Witten--Veneziano formula for the eta&#39; mass on the lattice, which looks like the formal continuum one, if the expression of the topological charge density operator, suggested by fermions obeying the Ginsparg--Wilson relation, is employed. By using recent numerical results

A. A. Bichl, J. M. Grimstrup, H. Grosse, E. Kraus

We show that the noncommutative Yang-Mills field forms an irreducible representation of the (undeformed) Lie algebra of rigid translations, rotations and dilatations. The noncommutative Yang-Mills action is invariant under combined conformal transformations of the Yang-Mills field and of the noncommutativity parameter θ. The Seiberg-Witten differential equat

S. Franz, R. Mulet, G. Parisi

We present new results reflecting the analogies between the Kob-Andersen model and other glassy systems. Studying the stability of the blocked configurations above and below the transition we also give arguments that supports their relevance for the glassy behaviour of the model. However we find, surprisingly, that the organization of the phase space of the

R. G. Vishwakarma

We examine the status of various dark energy-models in light of the recently observed SN 1997ff at z \approx 1.7. The modified data still fit a pure cosmological constant Λor a quintessence with an equation of state similar to that of Λ. The kinematical Λ-models, Λ\sim S^{-2} and Λ\sim H^2, also fit the data reasonably well and require less dark energy densi

Annette Ferguson, Rachel Johnson

Numerical simulations of galaxy formation within the cold dark matter (CDM) hierarchical clustering framework are unable to produce large disk galaxies without invoking some form of feedback to suppress gas cooling and collapse to a redshift of unity or below. An important observational consequence of delaying the epoch of disk formation until relatively rec

J. A. Appel, M. Artuso, J. N. Butler, G. Cancelo

The silicon pixel vertex detector is a key element of the BTeV spectrometer. Sensors bump-bonded to prototype front-end devices were tested in a high energy pion beam at Fermilab. The spatial resolution and occupancies as a function of the pion incident angle were measured for various sensor-readout combinations. The data are compared with predictions from o

Orion Ciftja, C. Wexler

We investigate broken rotational symmetry (BRS) states for the fractional quantum Hall effect (FQHE) at 1/3-filling of the valence Landau level (LL). Recent Monte Carlo calculations by Musaelian and Joynt [J. Phys.: Condens.\ Matter {\bf 8}, L105 (1996)] suggest that Laughlin&#39;s state becomes unstable to a BRS state for some critical finite thickness valu

Richard J. Szabo

The properties of brane-antibrane systems and systems of unstable D-branes in Type II superstring theory are investigated using the formalism of superconnections. The low-energy open string dynamics is shown to be probed by generalized Dirac operators. The corresponding index theorems are used to compute the chiral gauge anomalies in these systems, and hence

Bodo Geyer, Dietmar Mülsch

The Blau-Thompson N_T=2, D=3 nonequivariant topological model is extended to a N_T=4, D=3 topological theory. The latter, formally, may be regarded as a topological deformation of the N_T=2, D=4 Yamrom-Vafa-Witten theory after dimensional reduction to D=3. For completeness, also the dimensional reduction of the half-twisted N_T=2, D=4 Yamron model is explici

K. N. Anagnostopoulos, J. Nishimura

Monte Carlo simulations of a system whose action has an imaginary part are considered to be extremely difficult. We propose a new approach to this `complex-action problem&#39;, which utilizes a factorization property of distribution functions. The basic idea is quite general, and it removes the so-called overlap problem completely. Here we apply the method t

O. Lauscher, M. Reuter

A new exact renormalization group equation for the effective average action of Euclidean quantum gravity is constructed. It is formulated in terms of the component fields appearing in the transverse-traceless decomposition of the metric. It facilitates both the construction of an appropriate infrared cutoff and the projection of the renormalization group flo

Chun-Khiang Chua, Wei-Shu Hou, Shang-Yuu Tsai

We predict the rates of the charmless three-body $B^0\to ρ^-p\bar{n}$ and $π^-p\bar{n}$ modes due to weak vector current contributions to be $\sim 4\times 10^{-6}$ and $2\times 10^{-6}$, respectively. The basis is a factorization approach of current produced nucleon pairs, together with an isospin transformation that relates nucleon weak vector form factors

J. K. Bhattacharjee, Analabha Roy

We treat the double well quantum oscillator from the standpoint of the Ehrenfest equation but in a manner different from Pattanayak and Schieve. We show that for short times there can be chaotic motion due to quantum fluctuations, but over sufficiently long times the behaviour is normal.

M. Moriconi

We find new integrable boundary conditions, depending on a free parameter $g$, for the O(N) nonlinear $σ$ model, which are of nondiagonal type, that is, particles can change their ``flavor&#39;&#39; through scattering off the boundary. These boundary conditions are derived from a microscopic boundary lagrangian, which is used to establish their integrability

T. Csörgő, S. V. Akkelin, Y. Hama, B. Lukács

Single-particle spectra and two-particle Bose-Einstein correlation functions are determined analytically utilizing a self-similar solution of non-relativistic hydrodynamics for ellipsoidally-symmetric, expanding fireballs, by assuming that the symmetry axes of the ellipsoids are tilted in the frame of the observation. The directed, elliptic and third flows a

Aalok Misra

We show that in a certain region of a negative coordinate axis, the U(1amaharia) sector of the static dyonic solutions to the noncommutative U(4) N=4 Super Yang-Mills (SYM) can be consistently decoupled from the SU(4) to {\it all orders in the noncommutativity parameter}. We show the above decoupling in two ways. First, we show the noncommutative dyon being

D. A. Ryndyk, J. Keller, C. Helm

Nonequilibrium effects in layered superconductors forming a stack of intrinsic Josephson junctions are investigated. We discuss two basic nonequilibrium effects caused by charge fluctuations on the superconducting layers: a) the shift of the chemical potential of the condensate and b) charge imbalance of quasi-particles, and study their influence on IV-curve

M. Ruzzi

From a development of an original idea due to Schwinger, it is shown that it is possible to recover, from the quantum description of a degree of freedom characterized by a finite number of states (\QTR{it}{i.e}., without classical counterpart) the usual canonical variables of position/momentum \QTR{it}{and} angle/angular momentum, relating, maybe surprisingl

Roberta Zambrini, Stephen M. Barnett, Pere Colet, Maxi San Miguel

We investigate quantum effects in pattern-formation for a degenerate optical parametric oscillator with walk-off. This device has a convective regime in which macroscopic patterns are both initiated and sustained by quantum noise. Familiar methods based linearization about a pseudo-classical field fail in this regime and new approaches are required. We emplo

M. Daum, M. Finger, M. Finger,, J. Franz

The reaction ${n} {p} \to {p} {p} π^{-}$ has been studied in a kinematically complete measurement with a large acceptance time-of-flight spectrometer for incident neutron energies between threshold and 570 MeV. The proton-proton invariant mass distributions show a strong enhancement due to the pp($^{1}{S}_{0}$) final state interaction. A large anisotropy was

Oleg Y. Gnedin, HongSheng Zhao

The observed rotation curves of dark matter-dominated dwarf galaxies indicate low density cores, contrary to the predictions of CDM models. A possible solution of this problem involves stellar feedback. A strong baryonic wind driven by vigorous star formation can remove a large fraction of the gas, causing the dark matter to expand. We explore the maximum ef

L. Tewordt, D. Fay

We calculate the ultrasonic attenuation in magnetic fields for superconducting states with line nodes vertical or horizontal relative to the RuO_2 planes. This theory, which is valid for fields near Hc2 and not too low temperatures, takes into account the effects of supercurrent flow and Andreev scattering by the Abrikosov vortex lattice. For rotating in-pla

A. N. Schellekens, Ya. S. Stanev

Assuming the completeness condition for boundaries we derive trace formulas for the annulus coefficients in 2-dimensional conformal field theory. We also derive polynomial equations that relate the annulus, Moebius and Klein bottle coefficients, and conjecture an annulus trace formula that is sensitive to the orientation of the boundaries.