October 1998 arXiv papers — page 10

R. Erichsen, W. K. Theumann

The principle of adaptation in a noisy retrieval environment is extended here to a diluted attractor neural network of Q-state neurons trained with noisy data. The network is adapted to an appropriate noisy training overlap and training activity which are determined self-consistently by the optimized retrieval attractor overlap and activity. The optimized st

J. J. Rodríguez--Núñez, H. Ghosh

Using the Dyson equation of motion for both the diagonal one-particle Green function, $G(\vec{k},ω)$ and off--diagonal Green function, $F(\vec{k},ω)$, at the level of the Hubbard--I decoupling scheme, we have found that they have four poles symmetric in pairs, justifying a more elaborated calculation done by the Zürich group by means of the $T$-Matrix approa

T. P. C. van Noije, M. H. Ernst, E. Trizac, I. Pagonabarraga

The nonequilibrium steady state of a granular fluid, driven by a random external force, is demonstrated to exhibit long range correlations, which behave as $\sim 1/r$ in three and $\sim \ln(L/r)$ in two dimensions. We calculate the corresponding structure factors over the whole range of wave numbers, and find good agreement with two-dimensional molecular dyn

G. G. N. Angilella, R. Pucci, F. Siringo, A. Sudbo

We study the k-dependence of the gap function of a bilayer superconductor, using standard mean-field techniques applied to a 2D extended Hubbard model, in the presence of coherent interlayer pair-tunneling and quenched coherent single-particle tunneling. The intralayer pairing potential thus defined is expandable in a finite number of basis functions for the

I. V. Krive, E. R. Mucciolo

We consider the ballistic transport of quasiparticles with exclusion statistics through a 1D wire within the Landauer-Buttiker approach. We demonstrate that quasiparticle transport coefficients (electrical and heat conductance, as well as thermopower) are determined by the same general formulae as for particles with normal statistics. By applying the develop

C. Groeber, M. G. Zacher, R. Eder

We study the transition from paramagnetic metal to paramagnetic insulator by finite temperature Quantum Monte-Carlo simulations for the 2D Hubbard model at half-filling. Working at the moderately high temperature T=0.33*t where the spin correlation length has dropped to 1.5 lattice spacings, and scanning the interaction strength U, we observe an unambiguous

Teemu Pohjola, Jürgen König, Herbert Schoeller, Gerd Schön

We study the electron transport through a system of two low-capacitance metal islands connected in series between two electrodes. The work is motivated in part by experiments on semiconducting double-dots, which show intriguing effects arising from coherent tunneling of electrons and mixing of the single-electron states across tunneling barriers. In this art

T. G. Sokolovska, R. O. Sokolovskii

We present the theoretical phase diagrams of the classical Heisenberg fluid in an external magnetic field. A consistent account of correlations is carried out by the integral equation method. A nonmonotoneous effect of fields on the temperature of the gas-liquid critical point is found. Within the mean spherical approximation this nonmonotoneous behavior dis

P. R. C. Kent, Randolph Q. Hood, A. J. Williamson, R. J. Needs

Further developments are introduced in the theory of finite size errors in quantum many-body simulations of extended systems using periodic boundary conditions. We show that our recently introduced Model Periodic Coulomb interaction [A. J. Williamson et al., Phys. Rev. B 55, R4851 (1997)] can be applied consistently to all Coulomb interactions in the system.

Marcin Mierzejewski, Maciej M. Maska

We address a problem of the upper critical field in a lattice described by a two-dimensional tight-binding model with the on-site pairing. We develop a finite-system-approach which enables investigation of magnetic and superconducting properties of electrons on clusters, consisting of a few thousand sites. We discuss how the quasiparticle density of states c

H. Takasaki, T. Hikihara, T. Nishino

The density matrix renormalization group (DMRG) is a numerical method that optimizes a variational state expressed by a tensor product. We show that the ground state is not fully optimized as far as we use the standard finite system algorithm, that uses the block structure B**B. This is because the tensors are not improved directly. We overcome this problem

Jian-Sheng Wang

We analyze a new Monte Carlo method which uses transition matrix in the space of energy. This method gives an efficient reweighting technique. The associated artificial dynamics is a constrained random walk in energy, producing the result that correlation time is proportional to the specific heat.

Kouichi Okunishi, Yasuhiro Hieida, Yasuhiro Akutsu

We study the asymptotic behavior of the eigenvalue distribution of the Baxter's corner transfer matrix (CTM) and the density matrix (DM) in the White's density-matrix renormalization group (DMRG), for one-dimensional quantum and two-dimensional classical statistical systems. We utilize the relationship ${\rm DM}={\rm CTM}^4$ which holds for non-criti

T. Senthil, Matthew P. A. Fisher

We study the density of quasiparticle states of dirty d-wave superconductors. We show the existence of singular corrections to the density of states due to quantum interference effects. We then argue that the density of states actually vanishes in the localized phase as $|E|$ or $E^2$ depending on whether time reversal is a good symmetry or not. We verify th

A. Kaminski, L. I. Glazman

We study fluctuations of conductance of two connected in series dots in the Coulomb blockade regime. The pattern of the fluctuations turns out to be extremely sensitive to a magnetic field. These conductance fluctuations also provide information about the mesoscopic fluctuations of charge of a partially-opened single quantum dot, which are hard to measure di

Itai Arad, Victor S. L'vov, Itamar Procaccia

The theory of fully developed turbulence is usually considered in an idealized homogeneous and isotropic state. Real turbulent flows exhibit the effects of anisotropic forcing. The analysis of correlation functions and structure functions in isotropic and anisotropic situations is facilitated and made rational when performed in terms of the irreducible repre

A. Crider, E. P. Liang, R. D. Preece, M. S. Briggs

We have analyzed the evolution of the spectral hardness parameter Epk as a function of fluence in gamma-ray bursts. We fit 41 pulses within 26 bursts with the trend reported by Liang & Kargatis (1996) which found that Epk decays exponentially with respect to photon fluence. We also fit these pulses with a slight modification of this trend, where Epk decays l

K. Sakamoto, N. Z. Scoville, M. S. Yun, M. Crosas

The ultraluminous infrared galaxy Arp 220 has been observed at 0.5" resolution in CO(2-1) and 1 mm continuum using the newly expanded Owens Valley Millimeter Array. The CO and continuum peaks at the double nuclei and the surrounding molecular gas disk are clearly resolved. We find steep velocity gradients across each nucleus (dV ~ 500 km/s within r= 0.3&

Eve C. Ostriker

Using time-dependent linear perturbation theory, we evaluate the dynamical friction force on a massive perturber M_p traveling at velocity V through a uniform gaseous medium of density rho_0 and sound speed c_s. This drag force acts in the direction -\hat V, and arises from the gravitational attraction between the perturber and its wake in the ambient medium

Joel Wm. Parker, S. Alan Stern, G. Randall Gladstone, J. Michael Shull

Direct measurements of the abundance of argon in the lunar atmosphere were made in 1973 by instruments placed on the Moon during the Apollo 17 mission, but the total daytime abundance is unknown due to instrument saturation effects; thus, until we are able to return to the Moon for improved direct measurements, we must use remote sensing to establish the day

Eve C. Ostriker, Charles F. Gammie, James M. Stone

The molecular component of the Galaxy is comprised of turbulent, magnetized clouds, many of which are self-gravitating and form stars. To understand how these clouds' evolution may depend on their level of turbulence, mean magnetization, and degree of self-gravity, we perform a survey of direct numerical MHD simulations in 2.5 dimensions. Two of our inde

Walter Dehnen

From the tangential velocities of stars all over the sky, one can, in a statistical way, infer their 3D velocity distribution. An application to Hipparcos data reveals rich structure in the planar stellar motions: there are several moving groups, increasing in number with stellar type but decreasing in importance. A distinct group of outward moving stars wit

Rita M. Sambruna, G. Ghisellini, Eric Hooper, R. I. Kollgaard

We present ASCA observations of the radio-selected BL Lacertae objects 1749+096 (z=0.32) and 2200+420 (BL Lac, z=0.069) performed in 1995 Sept and Nov, respectively. The ASCA spectra of both sources can be described as a first approximation by a power law with photon index Gamma ~ 2. This is flatter than for most X-ray-selected BL Lacs observed with ASCA, in

J. G. Bartlett, A. Blanchard, M. Douspis, M. Le Dour

We discuss the constraints one can place on cosmological parameters using current cosmic microwave background data. A standard $χ^2$--minimization over band--power estimates is first presented, followed by a discussion of the more correct likelihood approach. We propose an approximation to the complete likelihood function of an arbitrary experiment requiring

Ulrich Kolb

Relativistic jets can extract mass-energy from a black hole. In semi-detached black hole binaries the jet ejection process constitutes a `consequential angular momentum loss' (CAML) process. The effect of this jet-induced CAML is to lower the transfer rate below the value set by systemic driving and to stabilize otherwise unstable systems. Implications o

J. G. Bartlett, A. Blanchard, M. Douspis, M. Le Dour

We discuss the problem of constraining cosmological parameters with cosmic microwave background band--power estimates. Because these latter are variances, they do not have gaussian distribution functions and, hence, the standard $χ^2$--approach is not strictly applicable. A general purpose approximation to experimental band--power likelihood functions is pro

Ulrich Kolb, Isabelle Baraffe

Using improved, up-to-date stellar input physics tested against observations of low-mass stars and brown dwarfs we calculate the secular evolution of low-mass donor CVs, including those which form with a brown dwarf donor star. Our models confirm the mismatch between the calculated minimum period (P_min ~ 70min) and the observed short-period cut-off (~80min)

A. Orr, A. N. Parmar, M. Orlandini, F. Frontera

We report results of two BeppoSAX observations of the transient X-ray source XTE J0421+560 during the outburst that started in March 1998. The source exhibits radio jets and coincides with the binary system CI Cam. The 0.1--50 keV spectrum is unlike those of other X-ray transients, and cannot be fit with any simple model. The spectra can be represented by an

Tsutomu T. Takeuchi, Hiroyuki Hirashita

We analyzed 10 dwarf spheroidal galaxies (dSphs) in the Local Group, and found two distinct sequences on the $M_{\rm vir} / L$ -- $M_{\rm vir}$ plane: $M_{\rm vir} / L \propto M_{\rm vir}^{1.6}$ for $M_{\rm vir} < 10^8 M_\odot$ whereas $M_{\rm vir} / L \simeq {\rm const.}$ for $M_{\rm vir} > 10^8 M_\odot$ ($M_{\rm vir}$ and $L$ are the virial mass and the to

Sergio Ortolani, Stefano Covino, Giovanni Carraro

The globular cluster Omega Centauri (NGC 5139) is the most massive and brightest cluster in our Galaxy. It has also a moderately high mass to light ratio (3.6) and an anomalous flattening (0.83) for a globular cluster. This cluster is also very interesting because it is one of a few examples of globular clusters with a measurable spread in the metal abundanc

Nahum Arav, Kirk T. Korista, Martijn de Kool, Vesa T. Junkkarinen

We analyze HST and ground based spectra of the brightest BALQSO in the UV: PG~0946+301. A detailed study of the absorption troughs as a function of velocity is presented, facilitated by the use of a new algorithm to solve for the optical depth as a function of velocity for multiplet lines. We find convincing evidence for saturation in parts of the troughs. T

S. Scopel, I. G. Irastorza, S. Cebrian, E. Garcia

A calculation of the expected signal due to Primakov coherent conversion of solar axions into photons via Bragg scattering in several solid--state detectors is presented and compared with present and future experimental sensitivities. The axion window m_a>~0.03 eV (not accessible at present by other techniques) could be explored in the foreseeable future wit

J. Kerp, W. B. Burton, R. Egger, M. J. Freyberg

We correlate the ROSAT 1/4 keV all-sky survey with the Leiden/Dwingeloo HI survey, looking for soft X-ray signatures of prominent high-velocity-cloud (HVC) complexes. We study the transfer of 1/4 keV photons through the interstellar medium in order to distinguish variations in the soft X-ray background (SXRB) intensity caused by photoelectric absorption effe

Eric Emsellem, Herwig Dejonghe, Roland Bacon

We present new dynamical models of the S0 galaxy N3115, making use of the available published photometry and kinematics as well as of two-dimensional TIGER spectrography. We first examined the kinematics in the central 40 arcsec in the light of two integral f(E,J) models. Jeans equations were used to constrain the mass to light ratio, and the central dark ma

L. Feretti, R. Perley, G. Giovannini, H. Andernach

In this paper we present multifrequency VLA observations of the giant radio galaxy 3C 449, obtained with high sensitivity and resolution in total intensity and polarized flux. These images show the source morphology in great detail, in particular we detect plumes and wiggles in the low brightness lobes. The source is considerably polarized at all frequencies

Alvio Renzini

Clusters of galaxies allow a direct estimate of the metallicity and metal production yield on the largest scale so far. It is argued that cluster metallicity ($\sim 1/3$ solar) should be taken as representative of the low-$z$ universe as a whole. There is now compelling evidence that the bulk of stars not only in cluster ellipticals but also in field ellipti

Peter Berczik

A new Chemo -- Dynamical Smoothed Particle Hydrodynamic (CD -- SPH) code is presented. The disk galaxy is described as a multi -- fragmented gas and star system, embedded into the cold dark matter halo. The star formation (SF) process, SNII, SNIa and PN events as well as chemical enrichment of gas have been considered within the framework of standard SPH mod

Mordehai Milgrom

The Modified dynamics (MOND) has been propounded as an alternative to Dark matter. It imputes the mass discrepancy in galaxy systems to failure of standard dynamics in the limit of small accelerations. After a brief description of the MOND tenets, I discuss how its predictions now compare with the data. I put special emphasis on rotation-curve analysis--when

Noah Brosch

Dwarf galaxies (DGs) are more numerous than large galaxies. Most dwarfs in clusters are dEs, but in the field they belong mostly to late types. The importance of late-type DGs in the context of the intergalactic medium (IGM) lies in the fact that (at least some) are probably ``young&#39;&#39; galaxies forming stars for the first time. Many DGs have significa

Bruno Leibundgut, J. Gordon Robertson

We present new spectroscopic observations of the quasar Q2059-360, confirming the existence of an emission feature within the Damped Lyman Alpha (DLA) absorption trough. By observing also at slit positions offset from the quasar, we show that the emission is spatially extended by at least a few arcseconds, and hence confirm that the feature seen must be due

Taft E. Armandroff, James E. Davies, George H. Jacoby

By applying a digital filtering technique to 1550 square degrees of the POSS-II in the vicinity of M31, we found two previously unidentified very low surface brightness dwarf galaxies which we designate And V and VI. Follow-up imaging with the KPNO 4-m telescope resolved these into stars easily. The V- and I- band images of And V indicate a distance similar

R. Brent Tully, Edward J. Shaya

Modeling of the velocity field of the Local Supercluster leads to the conclusion that there must be a substantial differential between the mass-to-light ratios of most galaxies and those in a small number of special places. Specifically, M/L=1000 is indicated for the full Virgo Cluster while M/L=150 is appropriate for most environments. It is argued that a h

Marc Verheijen, Brent Tully

A complete sample of spiral galaxies in the Ursa Major cluster is imaged at various optical wavelengths and in the Near-Infrared K&#39;-band. HI rotation curves were obtained for all gas rich systems. The Near-Infrared surface brightness distribution of disk galaxies turns out to be bimodal; galaxies avoid a domain around a face-on disk central surface brigh

M. J. Drinkwater, S. Phillipps, J. B. Jones

The Fornax Spectroscopic Survey is a large optical spectroscopic survey of ALL 14,000 objects with 16.5<Bj<19.7 in a 12 sq.deg area of sky centered on the Fornax Cluster. We are using the 400-fibre Two Degree Field spectrograph on the Anglo-Australian Telescope: the multiplex advantage of this system allows us to observe objects conventionally classified as

M. J. Drinkwater, S. Phillipps, J. B. Jones, M. D. Gregg

We are using the 2dF spectrograph to make a survey of all objects (`stars&#39; and `galaxies&#39;) in a 12 sq.deg region towards the Fornax cluster. We have discovered a population of compact emission-line galaxies unresolved on photographic sky survey plates and therefore missing in most galaxy surveys based on such material. These galaxies are as luminous

C. Firmani, V. Avila-Reese

Making use of a seminumerical method we develop a scenario of disk galaxy formation and evolution in the framework of inflationary cold dark matter (CDM) cosmologies. Within the virializing dark matter halos, disks in centrifugal equilibrium are built-up and their galactic evolution is followed through an approach which considers the gravitational interactio

M. Ramella, M. Nonino, W. Boschin, D. Fadda

We propose an automated method for detecting galaxy clusters in imaging surveys based on the Voronoi tessellation technique. It appears very promising, expecially for its capability of detecting clusters indipendently from their shape. After a brief explanation of our use of the algorithm, we show here an example of application based on a strip of the ESP Ke

A. Bezryadin, R. M. Westervelt, M. Tinkham

We report a technique which allows self-assembly of conducting nanoparticles into long continuous chains. Transport properties of such chains have been studied at low temperatures. At low bias voltages, the charges are pinned and the chain resistance is exponentially high. Above a certain threshold ($V_{T}$), the system enters a conducting state. The thresho

M. M. Guzzo, H. Nunokawa

We discuss the current status of the resonant spin-flavor precession (RSFP) solution to the solar neutrino problem. We perform a fit to all the latest solar neutrino data for various assumed magnetic field profiles in the sun. We show that the RSFP can account for all the solar neutrino experiments, giving as good fit as other alternative solutions such as M

Hanno Hammer

We investigate the possibility of semigroup extensions of the isometry group of an identification space, in particular, of a compactified spacetime arising from an identification map $p: \RR^n_t \to \RR^n_t / Γ$, where $\RR^n_t$ is a flat pseudo-Euclidean covering space and $Γ$ is a discrete group of primitive lattice translations on this space. We show that

Mirjam Cvetic

We review the status of microscopic counting of rotating black hole degrees of freedom. We present two complementary approaches which both utilize the near-horizon geometry and precisely reproduce the Bekenstein Hawking entropy for near-extreme rotating black holes in D=4 and D=5. The first one, proposed by Strominger, is applicable for the Ramond-Ramond sec

Mario Triantafillou, Randall D. Kamien

We calculate the second and third virial coefficients of the effective sphere-sphere interaction due to polymer depletion. By utilizing the anisotropy of a typical polymer conformation, we can consider polymers that are roughly the same size as the spherical inclusions. We argue that recent experiments can confirm this anisotropy.

Szu-yuan Chen, Anatoly Maksimchuk, Donald Umstadter

A century ago, J. J. Thomson showed that the scattering of low-intensity light by electrons was a linear process (i.e., the scattered light frequency was identical to that of the incident light) and that light&#39;s magnetic field played no role. Today, with the recent invention of ultra-high-peak-power lasers it is now possible to create a sufficient photon

S. Pleutin, J-L Fave

Starting from the $π$-electron Pariser-Parr-Pople (PPP) Hamiltonian which includes both strong electron-phonon and electron-electron interactions, we propose some strongly correlated wave functions of increasing quality for the ground state of conjugated polymers. These wavefunctions are built by combining different finite sets of local configurations extend

Filipe Bonjour, Roberto Emparan, Ruth Gregory

It has been claimed that extreme black holes exhibit a phenomenon of flux expulsion for abelian Higgs vortices, irrespective of the relative width of the vortex to the black hole. Recent work by two of the authors showed a subtlety in the treatment of the event horizon, which cast doubt on this claim. We analyse in detail the vortex/extreme black hole system

P. O. Hess, A. Weber, C. R. Stephens, S. A. Lerma H.

Using simple and general arguments we propose an effective Hamiltonian for the description of low-energy pure QCD. The Hamiltonian is a function of spatially constant collective modes. Its eigenstates can be organized into bands classified by the irreducible representations of an O(8) group. The latter also determine parity and charge conjugation of the stat

Oktay K. Pashaev, Jyh-Hao Lee

A new resonance version of NLS equation is found and embedded to the reaction-diffusion system, equivalent to the anti-de Sitter valued Heisenberg model, realizing a particular gauge fixing condition of the Jackiw-Teitelboim gravity. The space-time points where dispersion change the sign correspond to the event horizon, and the soliton solutions to the AdS b

Ulrich Heinz

Thermal models are commonly used to interpret heavy-ion data on particle yields and spectra and to extract the conditions of chemical and thermal freeze-out in heavy-ion collisions. I discuss the usefulness and limitations of such thermal model analyses and review the experimental and theoretical evidence for thermalization in nuclear collisions. The crucial

V. Berezinsky, A. Mikhailov

The harmonic analysis of anisotropy of Ultra High Energy Cosmic Rays is performed for the Dark Matter halo model. In this model the relic superheavy particles comprise part of the Dark Matter and are concentrated in the Galactic halo. The Ultra High Energy Cosmic Rays are produced by the decays of these particles. Anisotropy is caused by the non-central posi

H. Potempa, L. Schweitzer

We investigate numerically the influence of Dirichlet boundary conditions on the nearest neighbor level spacing distribution $P(s)$ of a two-dimensional disordered tight-binding model in the presence of a strong perpendicular magnetic field. From the calculation of the second moment of $P(s)$ it is shown that for Dirichlet boundary conditions, due to the pre

R. M. Noack, F. Gebhard

We calculate the zero-temperature gap and quasiparticle weight of the half-filled Hubbard model with a random dispersion relation. After extrapolation to the thermodynamic limit, we obtain reliable bounds on these quantities for the Hubbard model in infinite dimensions. Our data indicate that the Mott-Hubbard transition is continuous, i.e., that the quasipar

T. Giamarchi, A. M. Tsvelik

We investigate the phase transitions in two-leg ladders systems in the incommensurate phase, for which the gap is destroyed by a magnetic field ($h_{c1}< h$) and the ladder is not yet totally saturated ($h < h_{c2}$). We compute quantitatively the correlation functions as a function of the magnetic field for an isolated strong coupling ladder $J_\perp \gg J_

Xiao-Gang He

Several methods proposed to measure the angle $γ$ in the KM unitarity triangle assumed that the tree contribution to $B^-\to π^-\bar K^0 $ is purely due to annihilation contributions and is negligibly small. This assumption has to be tested in order to have a correct interpretation of the experimental data. In this paper we show that using SU(3) symmetry, th

Yuji Satoh

We investigate the connection between the BTZ black holes and the near-horizon geometry of higher-dimensional black holes. Under mild conditions, we show that (i) if a black hole has a global structure of the type of the non-extremal Reissner-Nordstrom black holes, its near-horizon geometry is $AdS_2$ times a sphere, and further (ii) if such a black hole is

A. González-Villanueva, E. Guillaumín-España, R. P. Martínez-y-Romero, H. N. Núñez-Yépez

The hodograph, i.e. the path traced by a body in velocity space, was introduced by Hamilton in 1846 as an alternative for studying certain dynamical problems. The hodograph of the Kepler problem was then investigated and shown to be a circle, it was next used to investigate some other properties of the motion. We here propose a new method for tracing the hod

M. J. Ablowitz, Y. Ohta, A. D. Trubatch

Two discretizations of the vector nonlinear Schrodinger (NLS) equation are studied. One of these discretizations, referred to as the symmetric system, is a natural vector extension of the scalar integrable discrete NLS equation. The other discretization, referred to as the asymmetric system, has an associated linear scattering pair. General formulae for soli

M. Ardehali

Bell&#39;s theorem of 1965 is a proof that all realistic interpretations of quantum mechanics must be non-local. Bell&#39;s theorem consists of two parts: first a correlation inequality is derived that must be satisfied by all local realistic theories; second it is demonstrated that quantum mechanical probabilities violate this inequality in certain cases. I

A. E. Allahverdyan, D. B. Saakian

We consider the problem of a state determination for a two-level quantum system which can be in one of two nonorthogonal mixed states. It is proved that for the two independent identical systems the optimal combined measurement (which considers the pair as one system) cannot be less optimal than the corresponding sequential one (local measurements, accompany

Shi-Hai Dong, Zhong-Qi Ma

Making use of an ${\it ansatz}$ for the eigenfunctions, we obtain an exact closed form solution to the non-relativistic Schrödinger equation with the anharmonic potential, $V(r)=a r^2+b r^{-4}+c r^{-6}$ in two dimensions, where the parameters of the potential $a, b, c$ satisfy some constraints.

Li Weigang

A Parallel Self-Organizing Map (Parallel-SOM) is proposed to modify Kohonen&#39;s SOM in parallel computing environment. In this model, two separate layers of neurons are connected together. The number of neurons in both layers and connections between them is the product of the number of all elements of input signals and the number of possible classification

K. Hamacher, W. Wenzel

We determined scaling laws for the numerical effort to find the optimal configurations of a simple model potential energy surface (PES) with a perfect funnel structure that reflects key characteristics of the protein interactions. Generalized Monte-Carlo methods(MCM, STUN) avoid an enumerative search of the PES and thus provide a natural resolution of the Le

M. Ardehali

The crucial role that Ions Energy Distribution Function (IEDF) at the electrodes plays in plasma processing of semiconductor materials demands that this quantity be predicted with high accuracy and with low noise levels in any plasma simulator. In this work, an efficient Particle-in-cell/Monte-Carlo (PIC/MC) simulator is developed to model IEDF at the electr

Dipendra Prasad, C. S. Yogananda

Merel has shown that the order of torsion subgroup of an elliptic curve over a number field can be bounded in terms of only the degree of the number field. The purpose of this note is to investigate what could be the `right bound&#39;. In this paper we use the result of Deuring on the supersingular primes for a CM elliptic curves to give estimate on the numb

Richard D. Canary, Yair N. Minsky, Edward C. Taylor

Let M be a compact 3-manifold whose interior admits a complete hyperbolic structure. We let Lambda(M) be the supremum of the bottom eigenvalue of the Laplacian of N, where N varies over all hyperbolic 3-manifolds homeomorphic to the interior of M. Similarly, we let D(M) be the infimum of the Hausdorff dimensions of limit sets of Kleinian groups whose quotien

Allan P. Donsig, S. C. Power

We obtain a complete classification of the locally finite algebras and the operator algebras, given as algebraic inductive limits and Banach algebraic inductive limits respectively, of direct systems: A_1 contained in A_2 contained in A_3 and so on. Here the A_k are 2n-cycle algebras, where n is at least 3 and the inclusions are of rigid type. The complete i

Jean-Claude Hausmann, Allen Knutson

We calculate the Riemann-Roch number of some of the pentagon spaces defined in [Klyachko,Kapovich-Millson,HK1]. Using this, we show that while the regular pentagon space is diffeomorphic to a toric variety, even symplectomorphic to one under arbitrarily small perturbations of its symplectic structure, it does not admit a symplectic circle action. In particul

Klaus Hulek, Kristian Ranestad

(1,d)-polarized abelian surfaces in P^(d-1) with two plane cubic curve fibrations lie in two elliptic P^2-scrolls. The union of these scrolls form a reducible Calabi-Yau 3-fold. In this paper we show that this occurs when d<10 and analyse the family of such surfaces and 3-folds in detail when d=6. In particular, the reducible Calabi-Yau 3-folds deform in tha

Yongluo Cao, Shin Kiriki

In this paper, we consider a smooth arc of diffeomorphisms which has a saddle-node bifurcation inside a nontrivial invariant set which is a deformation of a horseshoe. We show that this saddle-node bifurcation is isolated, that is, its hyperbolicity is maintained before and after the saddle-node bifurcation. Moreover we construct a $C^2$-open set of arcs hav

Lin Weng

In this paper, we introduce six axioms for relative Bott-Chern secondary characteristic classes and prove the uniqueness and existence theorem for them. Such a work provides us a natural way to understand and hence to prove the arithmetic Grothendieck-Riemann-Roch theorem.

Lin Weng

For singular metrics, there is no Quillen metric formalism on cohomology determinant. In this paper, we develop an admissible theory, with which the arithmetic Deligne-Riemann-Roch isometry can be established for singular metrics. As an application, we first study Weil-Petersson metrics and Takhtajan-Zograf metrics on moduli spaces of punctured Riemann surfa

Jin Hong

We construct a nondegenerate symmetric bilinear form on quantized enveloping algebras associated to Borcherds superalgebras. With this, we study its center and its universal R-matrix.

Uli Walther

Let $X=\C^n$. In this paper we present an algorithm that computes the de Rham cohomology groups $H^i_{dR}(U,\C)$ where $U$ is the complement of an arbitrary Zariski-closed set $Y$ in $X$. Our algorithm is a merger of the algorithm given by T.~Oaku and N.~Takayama (\cite{O-T2}), who considered the case where $Y$ is a hypersurface, and our methods from \cite{W

Allan P. Donsig, Tim D. Hudson, Elias G. Katsoulis

We prove that algebraic isomorphisms between limit algebras are automatically continuous, and consider consequences of this result. In particular, we give partial solutions to a conjecture of Power [Limit Algebras, Longman, 1992, Notes to Chapter 8] and to an open problem [op. cit., Problem 7.8]. As a further consequence, we describe epimorphisms between var

L. P. Colatto, M. A. De Andrade, F. Toppan

A manifestly Lorentz-covariant calculus based on two matrix-coordinates and their associated derivatives is introduced. It allows formulating relativistic field theories in any even-dimensional spacetime. The construction extends a single-coordinate matrix formalism based on coupling spacetime coordinates with the corresponding Gamma-matrices. A 2D matrix-ca

D. -S. Lee, P. N. McGraw, Y. J. Ng, I. A. Shovkovy

The effective potential for the composite fields responsible for chiral symmetry breaking in weakly coupled QED in a magnetic field is derived. The global minimum of the effective potential is found to acquire a non-vanishing expectation value of the composite fields that leads to generating the dynamical fermion mass by an external magnetic field. The resul

Fiorenzo Bastianelli

The proper definition and evaluation of the configuration space path integral for the motion of a particle in curved space is a notoriously tricky problem. We discuss a consistent definition which makes use of an expansion in Fourier sine series of the particle paths. Salient features of the regularization are the Lee-Yang ghosts fields and a specific effect

Sudipta Mukherji, Sudhakar Panda

We analyse the world-sheet perturbations of string theory formulated around $AdS_3$ background. We identify a set of operators that, while added to the world-sheet action, generate the boundary fluctuations of $AdS_3$. The effect of these operators can be collectively defined in terms of Liouville field living on the $AdS_3$ boundary. We then study various d

Marijan Ribaric, Luka Sustersic

We put forward the following, physically motivated premise for constructing a theory that underlies the standard model in four-dimensional space-time: The Euler-Lagrange equations of such a theory formally resemble some equations of motion underlying fluid-dynamics equations in the kinetic theory of gases. Following this premise, we point out Lorentz-invaria

S. James Gates,, Sergei M. Kuzenko

We consider additional properties of CNM (chiral-nonminimal) models. We show how 4D, N = 2 nonlinear sigma-models can be described solely in terms of N = 1 superfield CNM doublets. These actions are described by a Kahler potential together with an infinite number (in the general case) of terms involving its successively higher derivatives. We briefly discuss

Tadahiko Kimura

We show that the super D3-brane action on $AdS_5 \times S^5$ background recently constructed by Metsaev and Tseytlin is exactly invariant under the combination of the electric-magnetic duality transformation of the worldvolume gauge field and the SO(2) rotaion of N=2 spinor coordinates. The action is shown to satisfy the Gaillard-Zumino duality condition, wh

Sang Pyo Kim

We present the so-called Liouville-Neumann (LN) approach to nonequilibrium quantum fields. The LN approach unifies the functional Schrödinger equation and the LN equation for time-independent or time-dependent quantum systems and for equilibrium or nonequilibrium quantum systems. The LN approach is nonperturbative in that at the lowest order of coupling cons

I. Antoniadis, S. Dimopoulos, A. Pomarol, M. Quiros

We study the sparticle spectroscopy and electroweak breaking of theories where supersymmetry is broken by compactification (Scherk-Schwarz mechanism) at a TeV. The evolution of the soft terms above the compactification scale and the resulting sparticle spectrum are very different from those of the usual MSSM and gauge mediated theories. This is traced to the

Zvi Bern, Vittorio Del Duca, Carl R. Schmidt

For the case of $n$-jet production at next-to-next-to-leading order in the QCD coupling, in the infrared divergent corners of phase space where particles are collinear or soft, one must evaluate $(n+1)$-parton final-state one-loop amplitudes through $\Ord(\eps^2)$, where $\eps$ is the dimensional regularization parameter. For the case of gluons, we present t

Y. -Y. Keum

We consider penguin contributions to the lifetime splitting between the $B_s$ and the $B_d$ meson. In the Standard Model the penguin effects are found to be opposite in sign, but of similar magnitude as the contributions of the current-current operators, despite of the smallness of the penguin coefficients. We predict \begin{eqnarray} \frac{τ(B_s)}{τ(B_d)} -

Randall J. Sobie

The predictions of an isospin model are compared with the branching ratios of the 5 and 6 pion decays of the tau lepton. In both cases, the isospin model suggests that the tau favours decays in which there is an omega resonance. Recent measurements of such tau decays confirm this hypothesis. If the decay of the tau to 7 pions also proceeds through an interme

Sergio Bottini

A simple and general law of mass, intrinsically with zero freely-adaptable parameters, is shown to be valid for all the hadrons with one or more flavored (s, c, or b) quarks/antiquarks, both baryons and mesons. It establishes correspondences H-->{P_i} between these hadrons with at least one flavored constituent, H, and specific sets of lighter particles, {P_

V. Dmitrašinović

In the preceding Comment it is alleged that a &#34;hidden loophole&#34; in the proof of Hara&#39;s theorem has been found, which purportedly invalidates the conclusions of the paper commented upon. I show that there is no such loophole in the constituent quark model, and that the &#34;counterexample&#34; presented in the Comment is not gauge invariant.

Joao M. Soares

In semi-leptonic and other weak decays of mesons, the hadronic matrix elements of the operators in the weak Hamiltonian are parametrized by standard sets of independent, Lorentz invariant, form factors. For the case of pseudoscalar to vector meson transitions, it has been shown that a Quark Model description leads to relations between some of the form factor

S. L. Dubovsky, P. G. Tinyakov

We briefly review current theoretical and experimental status of Ultra-High Energy Cosmic Rays. We show that ``top-down&#39;&#39; mechanisms of UHE CR which involve heavy relic particle-like objects predict Galactic anisotropy of highest energy cosmic rays at the level of minimum $\sim 20%$. This anisotropy is large enough to be either observed or ruled out

P. Gambino, A. Kwiatkowski, N. Pott

We compute analytically the complete electroweak two-loop corrections to the $B^0-{\bar B}^0$ mixing. These corrections fix the normalization of the electroweak coupling employed in the extraction of $|V_{td}|$ and reduce the theoretical uncertainty due to higher order electroweak effects from several percent to a few parts in a thousand. If the LO result is