April 2002 arXiv papers — page 4

A. Derdzinski, G. Maschler

A special Kähler-Ricci potential on a Kähler manifold is any nonconstant $C^\infty$ function $τ$ such that $J(\nablaτ)$ is a Killing vector field and, at every point with $dτ\ne 0$, all nonzero tangent vectors orthogonal to $\nablaτ$ and $J(\nablaτ)$ are eigenvectors of both $\nabla dτ$ and the Ricci tensor. For instance, this is always the case if $τ$ is a

G. G. Amosov

We introduce Markovian cocycle perturbations of the groups of transformations associated with the classical and quantum stochastic processes with stationary increments, which are characterized by a localization of the perturbation to the algebra of events of the past. It is namely the definition one needs because the Markovian perturbations of the Kolmogorov

Clemens Berger, Benoit Fresse

The Barratt-Eccles operad is a simplicial operad formed by the classical homogeneous bar construction of the symmetric groups. We prove that these simplicial sets decompose as unions of prisms indexed by surjections. We observe that the cellular complexes given by this prismatic structure are nothing but the components of the surjection operad (the operad in

Kyousuke Uchino

The notion of Courant algebroid was introduced by Liu, Weinstein and Xu in 1997. Its definition consists of five axioms and an assumption for a derivation. It is shown that two of the axioms and the assumption for the derivation follow from the rest of the axioms.

I. M. Narodetskii, M. A. Trusov

We present some piloting calculations of the masses of the doubly heavy baryons in the framework of the simple approximation within the nonperturbative string approach. The simple analytical results for dynamical masses of heavy and light quarks and eigenvalues of the effective QCD Hamiltonian are presented.

Qing-hua Xu, Chun-xiu Liu, Zuo-tang Liang

We calculate the longitudinal polarizations of hyperons in high $p_\perp$ jets in $pp$ collisions in which one of the protons is longitudinally polarized at RHIC energies using different models for the spin transfer in fragmentation process. The results show that the measurements of these polarizations can be used to study the spin transfer in high energy fr

Jogesh C. Pati

It is noted that a set of facts points to the relevance in four dimensions of conventional supersymmetric unification based on minimally a string-unified G(224)-symmetry, or maximally SO(10). These include: (i) the observed family- structure, (ii) quantization of electric charge, (iii) meeting of the three gauge couplings, (iv) neutrino oscillations [in part

P. P. Divakaran

The lattice of integral points of 4-dimensional Minkowski space, together with the inherited indefinite distance function, is considered as a model for discrete space-time. The Lorentz and Poincare groups of this discrete space-time are identified as subgroups of the corresponding Lie groups. The lattice Lorentz group has irreducible projective (including li

Paul R. Anderson, Carmen Molina-Paris, Emil Mottola

We propose a quantitative test for the validity of the semi-classical approximation in gravity, namely that the solutions to the semi-classical equations should be stable to linearized perturbations, in the sense that no gauge invariant perturbation should become unbounded in time. We show that a self-consistent linear response analysis of these perturbation

Francisco J. Solis

Dilute solutions of strongly charged polymer electrolytes undergo, upon addition of multivaltent salt to the solutions, a phase transition from extended conformations to collapsed or bundled ones. Upon further addition of salt they experience a second transition, a redissolution back into extended conformations. This paper presents a theoretical study of the

D. V. Dmitriev, V. Ya. Krivnov, A. A. Ovchinnikov, A. Langari

One dimensional spin-1/2 $XXZ$ model in a transverse magnetic field is studied. It is shown that the field induces the gap in the spectrum of the model with easy-plain anisotropy. Using conformal invariance the field dependence of the gap at small fields is found. The ground state phase diagram is obtained. It contains four phases with different types of the

Milind N. Kunchur, B. I. Ivlev, J. M Knight

Current-voltage characteristics were measured in the mixed state of Y1Ba2Cu3O(7-delta) superconducting films in the regime where flux flow becomes unstable and the differential conductivity dj/dE becomes negative. Under conditions where its negative slope is steep, the j(E) curve develops a pronounced staircase like pattern. We attribute the steps in j(E) to

C. Pennetta, L. Reggiani, Gy. Trefan

The degradation of ultrathin oxide layers in the presence of a stress voltage is modeled in terms of two antagonist percolation processes taking place in a random resistor network. The resistance and leakage current fluctuations are studied by MonteCarlo simulations for voltages below the breakdown threshold. An increase of excess noise together with a notic

G. G. N. Angilella, E. Piegari, A. A. Varlamov

We study the superconducting properties of a two-dimensional superconductor in the proximity to an electronic topological transition (ETT). In contrast to the 3D case, we find that the superconducting gap at T=0, the critical temperature Tc, and the impurity scattering rate are characterized by a nonmonotonic behavior, with maxima occurring close to the ETT.

C. L. Gerardy, R. A. Fesen, K. Nomoto, P. Garnavich

Near-Infrared (NIR) observations are presented for five Type IIn supernovae (SN 1995N, SN 1997ab, SN 1998S, SN 1999Z, and SN 1999el) that exhibit strong infrared excesses at late times (t >= 100 d). H- and K-band emission from these objects is dominated by a continuum that rises toward longer wavelengths. The data are interpreted as thermal emission from dus

L. Testi, A. Natta, E. Oliva, F. D'Antona

We present a complete low-resolution (R~100) near-infrared spectrum of the substellar object GY11, member of the rho-Ophiuchi young association. The object is remarkable because of its low estimated mass and age and because it is associated with a mid-infrared source, an indication of a surrounding dusty disk. Based on the comparison of our spectrum with sim

Peter Teuben

Two dimensional velocity fields have been an important tool for nearly 30 years and are instrumental in understanding galactic mass distributions and deviations from an ideal galactic disk. Recently a number of new instruments have started to produce more detailed velocity fields of the disks and nuclear regions of galaxies. This paper summarizes some of the

Leonid Gurvits, Howard Barnum

For finite-dimensional bipartite quantum systems, we find the exact size of the largest balls, in spectral $l_p$ norms for $1 \le p \le \infty$, of separable (unentangled) matrices around the identity matrix. This implies a simple and intutively meaningful geometrical sufficient condition for separability of bipartite density matrices: that their purity $\tr

J. E. Cabanela, J. M. Dickey

We have successfully constructed a catalog of HI-rich galaxies selected from the Minnesota Automated Plate Scanner Catalog of the Palomar Observatory Sky Survey (POSS I) based solely on optical criteria. We identify HI-rich candidates by selecting the bluest galaxies at a given apparent magnitude, those galaxies on the "blue edge" of POSS I color-mag

A. P. Baeta Scarpelli, H. Belich, J. L. Boldo, J. A. Helayel-Neto

The gauge-invariant Chern-Simons-type Lorentz- and CPT-breaking term is here reassessed and a spin-projector method is adopted to account for the breaking (vector) parameter. Issues like causality, unitarity, spontaneous gauge-symmetry breaking and vortex formation are investigated, and consistency conditions on the external vector are identified.

Yan V. Fyodorov, Eugene Strahov

We have found an exact formula expressing a general correlation function containing both products and ratios of characteristic polynomials of random Hermitian matrices. The answer is given in the form of a determinant. An essential difference from the previously studied correlation functions (of products only) is the appearance of non-polynomial functions al

Yu. I. Latyshev, A. A. Sinchenko, L. N. Bulaevskii, V. N. Pavlenko

Characteristic features of transverse transport along the $a^*$ axis in the NbSe$_3$ charge-density-wave conductor are studied. At low temperatures, the $I$-$V$ characteristics of both layered structures and NbSe$_3$-NbSe$_3$ point contacts exhibit a strong peak of dynamic conductivity at zero bias voltage. In addition, the $I$-$V$ characteristics of layered

Sergio Doplicher, Gherardo Piacitelli

The assignment of local observables in the vacuum sector, fulfilling the standard axioms of local quantum theory, is known to determine uniquely a compact group G of gauge transformations of the first kind together with a central involutive element k of G, and a complete normal algebra of fields carrying the localizable charges, on which k defines the Bose/F

Fabio L. Braghin

Symmetry energy coefficients of explicitly isospin asymmetric nuclear matter at variable densities (from .5$ρ_0$ up to 2 $ρ_0$) are studied as generalized screening functions. An extended stability condition for asymmetric nuclear matter is proposed. We find the possibility of obtaining stable asymmetric nuclear matter even in some cases for which the symmet

O. V. Pavlovsky

Finite-energy topological spherically symmetrical solutions of Chiral Born-Infeld Theory are studied. Properties of these solution are obtained, and a possible physical interpretation is also given.

Elina Keihanen

We present a study of inhomogeneous big bang nucleosynthesis with emphasis on transport phenomena. We combine a hydrodynamic treatment to a nuclear reaction network and compute the light element abundances for a range of inhomogeneity parameters. We find that shortly after annihilation of electron-positron pairs, Thomson scattering on background photons prev

Russell Lyons, Jeffrey E. Steif

We study a class of stationary processes indexed by $\Z^d$ that are defined via minors of $d$-dimensional (multilevel) Toeplitz matrices. We obtain necessary and sufficient conditions for phase multiplicity (the existence of a phase transition) analogous to that which occurs in statistical mechanics. Phase uniqueness is equivalent to the presence of a strong

A. Bill, H. Morawitz, V. Z. Kresin

An essential property of layered systems is the dynamical nature of the screened Coulomb interaction. Low energy collective modes appear as a consequence of the layering and provide for a superconducting-pairing channel in addition to the electron-phonon induced attractive interaction. We show that taking into account this feature allows to explain the high

C. Hernandez-Monteagudo, A. Kashlinsky, F. Atrio-Barandela

We implement and further refine the recently proposed method (Kashlinsky, Hernández-Monteagudo & Atrio-Barandela, 2001 - KHA) for a time efficient extraction of the power spectrum from future cosmic microwave background (CMB) maps. The method is based on the clustering properties of peaks and troughs of the Gaussian CMB sky. The procedure takes only ${1/2}[f

Russell Lyons

Determinantal point processes have arisen in diverse settings in recent years and have been investigated intensively. We study basic combinatorial and probabilistic aspects in the discrete case. Our main results concern relationships with matroids, stochastic domination, negative association, completeness for infinite matroids, tail triviality, and a method

M. P. Hobson, C. McLachlan

A Bayesian approach is presented for detecting and characterising the signal from discrete objects embedded in a diffuse background. The approach centres around the evaluation of the posterior distribution for the parameters of the discrete objects, given the observed data, and defines the theoretically-optimal procedure for parametrised object detection. Tw

Borut Bajc, Pavel Fileviez Perez, Goran Senjanovic

We systematically study proton decay in the minimal supersymmetric SU(5) grand unified theory. We find that although the available parameter space of soft masses and mixings is quite constrained, the theory is still in accord with experiment.

D. Barquilla-Cano, A. J. Buchmann, E. Hernández

We discuss the axial form factors of the nucleon within the context of the nonrelativistic chiral quark model. Partial conservation of the axial current (PCAC) imposed at the quark operator level enforces an axial coupling for the constituent quarks which is smaller than unity. This leads to an axial coupling constant of the nucleon $g_A$ in good agreement w

Avishai Dekel, Jonathan Devor, Guy Hetzroni

We explain in simple terms how the buildup of dark haloes by merging compact satellites, as in the CDM cosmology, inevitably leads to an inner cusp of density profile $ρ\propto r^{-α}$ with $α\gsim 1$, as seen in cosmological N-body simulations. A flatter halo core with $α<1$ exerts on the satellites tidal compression in all directions, which prevents deposi

Tomohiro Matsuda

In generic models for grand unified theories(GUT), various types of baryon number violating processes are expected when quarks and leptons propagate in the background of GUT strings. On the other hand, in models with large extra dimensions, the baryon number violation in the background of a string is not trivial because it must depend on the mechanism of the

Vladimir I. Korobov

The helium ground state nonrelativistic energy with 24 significant digits is presented. The calculations are based on variational expansion with randomly chosen exponents. This data can be used as a benchmark for other approaches for many electron and/or three-body systems.

H. Fujii, T. Matsui

The transmission amplitude of a color dipole through a random external color field is computed in the eikonal approximation in order to study the absorption of high energy quarkonium by nuclear target. It is shown that the internal color state of the dipole becomes randomized and all possible color states are eventually equi-partitioned, while the probabilit

Svjetlana Fajfer, Anita Prapotnik, Paul Singer

The weak radiative Cabibbo allowed decays D^+ -> anti K^0 pi^+ gamma and D^0 -> K^- pi^+ gamma with nonresonant K pi are investigated by relying on the factorization approximation for the nonleptonic weak transitions and the model which combines the heavy quark effective theory and the chiral Lagrangian approach. The dominant contributions to the amplitudes

Anjan S. Joshipura, Subhendra Mohanty

Solar neutrinos with non-zero magnetic moments will contribute to the electron scattering rates in the Super-Kamiokande experiment. The magnetic moment scattering events in Super-K can be accommodated in the standard VO or MSW solutions by a change of the parameter space of mass square difference and mixing angle-but the shifted neutrino parameters obtained

Ugur Tirnakli

The mixing properties (or sensitivity to initial conditions) of two-dimensional Henon map have been explored numerically at the edge of chaos. Three independent methods, which have been developed and used so far for the one-dimensional maps, have been used to accomplish this task. These methods are (i)measure of the divergence of initially nearby orbits, (ii

Kang Young Lee, Wan Young Song

We explore the anomalous right-handed $\bar{t}sW$ and $\bar{t}bW$ couplings using $ B \to X_s γ$ and $B \to X_s l^+ l^-$ decays induced by the flavour-changing penguin diagrams. The anomalous $\bar{t}sW$ coupling can yield 10% enhancement of the $B \to X_s l^+ l^-$ decay rate under the constraint from the present $B \to X_s γ$ data, while it does not affect

V. Bartsch, W. de Boer, J. Bol, A. Dierlamm

Future experiments will use silicon sensors in the harsh radiation environment of the LHC (Large Hadron Collider) and high magnetic fields. The drift direction of the charge carriers is affected by the Lorentz force due to the high magnetic field. Also the resulting radiation damage changes the properties of the drift. In this paper measurements of the Loren

Kenji Fukushima

We investigate QCD in the canonical ensemble with respect to the quark number. We reveal that the canonical description in which the quark number is fixed would be reduced to the grand canonical description under the thermodynamic limit. Since the grand canonical ensemble contains fluctuations of the quark number, the idea of the canonical ensemble is of no

Ivone F. M. Albuquerque, Jodi Lamoureux, George F. Smoot

The nature of the dark matter of the Universe is yet unknown and most likely is connected with new physics. The search for its composition is under way through direct and indirect detection. Fundamental physical aspects such as energy threshold, geometry and location are taken into account to investigate proposed neutrino telescopes of km^3 volume sensitivit

S. Giacomini, F. Sciarrino, E. Lombardi, F. De Martini

We report the experimental realization of the &#39;&#39;active&#39;&#39; quantum teleportation (QST) of a one-particle entangled qubit. This demonstration completes the original QST protocol and renders it available for actual implementation in quantum computation networks. It is accomplished by implementing a 8m optical delay line and a single-photon trigge

M. Shifman

This article is a slightly expanded version of the talk I delivered at the Special Plenary Session of the 46-th Annual Meeting of the Israel Physical Society (Technion, Haifa, May 11, 2000) dedicated to Misha Marinov. In the first part I briefly discuss quantum tunneling, a topic which Misha cherished and to which he was repeatedly returning through his care

Joonwoo Bae, Younghun Kwon

In this letter, we show that the laser Hamiltonian can perform the quantum search. We also show that the process of quantum search is a resonance between the initial state and the target state, which implies that Nature already has a quantum search system to use a transition of energy. In addition, we provide the particular scheme to implement the quantum se

E. A. Kuznetsov

A sufficient integral criterion for a blow-up solution of the Hopf equations (the Euler equations with zero pressure) is found. This criterion shows that a certain positive integral quantity blows up in a finite time under specific initial conditions. Blow-up of this quantity means that solution of the Hopf equation in 3D can not be continued in the Sobolev

Rinat G. Ragachurin

The possibility of the fundamental interactions unification arises at the consideration of the field equation of the energy conservation if one takes into account Salam&#39;s effect. Such account results in the functional division between gravitational, strong and electromagnetic interactions. The division has the differential nature which is connected with

J. Adam,, Franz Gross, Sabine Jeschonnek, Paul Ulmer

Using the covariant spectator theory and the transversity formalism, the unpolarized, coincidence cross section for deuteron electrodisintegration, $d(e,e&#39;p)n$, is studied. The relativistic kinematics are reviewed, and simple theoretical formulae for the relativistic impulse approximation (RIA) are derived and discussed. Numerical predictions for the sca

Michail P. Rekalo, Egle Tomasi-Gustafsson

We analyze $J/ψ-$ production in nucleon-nucleon collisions near threshold in the framework of a general model independent formalism, which can be applied to any reaction $N+N\to N+N+V^0$, where $V^0=ω$, $ϕ$, or $J/ψ$. Such reactions show large isotopic effects: a large difference for $pp$- and $pn$-collisions, which is due to the different spin structure of

Lars Hufnagel, Roland Ketzmerick, Marc-Felix Otto, Holger Schanz

We report the failure of the semiclassical eigenfunction hypothesis if regular classical transport coexists with chaotic dynamics. All eigenstates, instead of being restricted to either a regular island or the chaotic sea, ignore these classical phase-space structures. We argue that this is true even in the semiclassical limit for extended systems with trans

Ashok Das, Sergey Krivonos, Ziemowit Popowicz

We present a systematic procedure for obtaining the dispersionless limit of a class of N=1 supersymmetric systems starting from the Lax description of their dispersive counterparts. This is achieved by starting with an N=2 supersymmetric system and scaling the fields in an alternative manner so as to maintain N=1 supersymmetry. We illustrate our method by wo

A. P. Veselov

It is proved that if the Schrödinger equation $L ψ= λψ$ of Calogero-Moser-Sutherland type with $$L = -Δ+ \sum\limits_{α\in{\cal A}_{+}} \frac{m_α(m_α+1) (α,α)}{\sin^{2}(α,x)}$$ has a solution of the product form $ψ_0 = \prod_{α\in {\cal {A}_+}} \sin^{-m_α}(α,x),$ then the function $F(x) =\sum\limits_{α\in \cal {A}_{+}} m_α (α,x)^2 {\rm log} (α,x)^2$ satisfie

David Krejcirik

Motivated by the theory of quantum waveguides, we investigate the spectrum of the Laplacian, subject to Dirichlet boundary conditions, in a curved strip of constant width that is defined as a tubular neighbourhood of an infinite curve in a two-dimensional Riemannian manifold. Under the assumption that the strip is asymptotically straight in a suitable sense,

Bruce W. Jordan, Ron Livné, Yakov Varshavsky

Using the p-adic uniformization of Shimura varieties we determine, for some of them, over which local fields they have rational points. Using this we show in some new curve cases that the jacobians are even in the sense of Poonen and Stoll.

Geoffrey Mason, Michael P. Tuite

We obtain explicit expressions for all genus one chiral n-point functions for free bosonic and lattice vertex operator algebras. We also consider the elliptic properties of these functions.

Andrei Moroianu, Uwe Semmelmann

Twistor forms are a natural generalization of conformal vector fields on Riemannian manifolds. They are defined as sections in the kernel of a conformally invariant first order differential operator. We study twistor forms on compact Kaehler manifolds and give a complete description up to special forms in the middle dimension. In particular, we show that the

Yuichiro Takeda

In this paper a concrete definition of higher K-theory in Arakelov geometry is given. The K-thoery defined in this paper is a higher extension of the arithmetic K_0 group of an arithmetic variety defined by Gillet and Soule. Products and direct images in this K-theory are discussed.

Gregory F. Lawler, Oded Schramm, Wendelin Werner

A planar self-avoiding walk (SAW) is a nearest neighbor random walk path in the square lattice with no self-intersection. A planar self-avoiding polygon (SAP) is a loop with no self-intersection. In this paper we present conjectures for the scaling limit of the uniform measures on these objects. The conjectures are based on recent results on the stochastic L

Marc Arnold Nieper-Wisskirchen

Let $A^{[[n]]}$ denote the $2(n - 1)$-dimensional generalised Kummer variety constructed from the abelian surface $A$. Further, let $X$ be an arbitrary smooth projective surface with $\int_X c_1(X)^2 \neq 0$, and $X^{[k]}$ the Hilbert scheme of zero-dimensional subschemes of $X$ of length $k$. We give a formula which expresses the value of any complex genus

Eduard Looijenga

We define a new class of completions of locally symmetric varieties of type IV which interpolates between the Baily-Borel compactification and Mumford&#39;s toric compactifications. An arithmetic arrangement in a locally symmetric variety of type IV determines such a completion canonically. This completion admits a natural contraction that leaves the complem

Rutwig Campoamor-Stursberg

We prove that if $\frak{g}^{\prime}$ is a contraction of a Lie algebra $\frak{g}$ then the number of functionally independent invariants of $\frak{g}^{\prime}$ is at least that of $\frak{g}$. This allows to determine explicitly the number of invariants of Lie algebras carrying a supplementary structure, such as linear contact or linear forms whose differenti

A. A. Rosly, K. G. Selivanov

We prove that the helicity is preserved in the scattering of photons in the Born-Infeld theory (in 4d) on the tree level.

Monika Marquart, Daniel Waldram

In this note, we use results of Aspinwall and Morrison to discuss the F-theory duals of certain $T^4/\bbZ_N$ orbifold compactifications of Hořava--Witten theory. In the M-theory limit an interesting set of rules, based on anomaly cancellation, has been developed for what gauge and matter multiplets must be present on the various orbifold fixed planes. Here w

Patrick Peter, Jerome Martin, Nelson Pinto-Neto, Dominik J. Schwarz

With the new cosmological data gathered over the last few years, the inflationary paradigm has seen its predictions largely unchallenged. A recent proposal, called the ekpyrotic scenario, was argued to be a viable competitor as it was claimed that the spectrum of primordial perturbations it produces is scale invariant. By investigating closely this scenario,

A. M. Kotzinian, O. Yu. Shevchenko, A. N. Sissakian

It is shown that the evaluation of the expectation value (EV) of topological charge density over $θ$-vacuum is reduced to investigation of the Chern-Simons term EV. An equation for this quantity is established and solved. EV of the topological charge density at an arbitrary $θ$ occurs equal to zero and, as a consequence, topological susceptibility of both QC

Joel Giedt

A review of orbifold geometry is given, followed by a review of the construction of four-dimensional heterotic string models by compactification on a six-dimensional Z_3 orbifold. Particular attention is given to the details of the transition from a classical theory to a first-quantized theory. Subsequently, a discussion is given of the systematic enumeratio

Enrico Meggiolaro

We discuss the role of the U(1) axial symmetry for the phase structure of QCD at finite temperature. We expect that, above a certain critical temperature, also the U(1) axial symmetry will be restored. We will try to see if this transition has (or has not) anything to do with the usual chiral transition: various possible scenarios are discussed. In particula

B. M. Gripaios

The Lorentz-invariant gluon correlation functions, corresponding to scalar and pseudo-scalar glueballs, are calculated for Kogan&#39;s and Kovner&#39;s variational ansatz for the pure SU(N) Yang-Mills wavefunctional. One expects that only one dynamical mass scale should be present in QCD; the ansatz generates the expected scale for both glueballs, as well as

H. -Th. Elze

Relativistic quantum transport theory has begun to play an important role in the space-time description of matter under extreme conditions of high energy density in out-of-equilibrium situations. The following introductory lectures on some of its basic concepts and methods comprise the sections: 1. Introduction; 2. Aims of transport theory (classical); 3. Qu

Daniele Binosi, Joannis Papavassiliou

The generalization of the two-loop Pinch Technique to the Electroweak Sector of the Standard Model is presented. We restrict ourselves to the case of conserved external currents, and provide a detailed analysis of both the charged and neutral sectors. The crucial ingredient for this construction is the identification of the parts discarded during the pinchin

Eugeny Babichev, Vyacheslav Dokuchaev

Chiral cosmic string loop tends to the stationary (vorton) configuration due to the energy loss into the gravitational and electromagnetic radiation. We describe the asymptotic behaviour of near stationary chiral loops and their fading to vortons. General limits on the gravitational and electromagnetic energy losses by near stationary chiral loops are found.

J. Greensite

I describe how the gluon chain model of QCD string formation meets a number of criteria which are required of any theory of the confining force, including: the correct center dependence and (at large-N) Casimir scaling of the string tension, the logarithmic broadening of the QCD flux tube, and the existence of a Luscher term in the static quark potential.

Kurt Langfeld

The SU(2) Yang-Mills gluon and ghost Green-functions are studied in Landau gauge by means of lattice gauge simulations. A focal point is their low energy behavior since in particular the Kugo-Ojima confinement criterion relates a diverging ghost form factor at vanishing momentum transfer to the confining capabilities of the theory. This divergence is verifie

Daisuke Ida, Ken-ichi Nakao

The initial data sets for the five-dimensional Einstein equation have been examined. The system is designed such that the black hole ($\simeq S^3$) or the black ring ($\simeq S^2\times S^1$) can be found. We have found that the typical length of the horizon can become arbitrarily large but the area of characteristic closed two-dimensional submanifold of the

Thomas W. Kephart, Y. Jack Ng

Vast amounts of entropy are produced in black hole formation, and the amount of entropy stored in supermassive black holes at the centers of galaxies is now much greater than the entropy free in the rest of the universe. Either mergers involved in forming supermassive black holes are rare,or the holes must be very efficient at capturing nearly all the entrop

Ramesh Narayan, Jeremy S. Heyl

Roughly a dozen X-ray binaries are presently known in which the compact accreting primary stars are too massive to be neutron stars. These primaries are identified as black holes, though there is as yet no definite proof that any of the candidate black holes actually possesses an event horizon. We discuss how Type I X-ray bursts may be used to verify the pre

Renaud Parentani

The study of acoustic black holes has been undertaken to provide new insights about the role of high frequencies in black hole evaporation. Because of the infinite gravitational redshift from the event horizon, Hawking quanta emerge from configurations which possessed ultra high (trans-Planckian) frequencies. Therefore Hawking radiation cannot be derived wit

Filippo Menczer

Can a Web crawler efficiently locate an unknown relevant page? While this question is receiving much empirical attention due to its considerable commercial value in the search engine community [Cho98,Chakrabarti99,Menczer00,Menczer01], theoretical efforts to bound the performance of focused navigation have only exploited the link structure of the Web graph,

Chris Bailey-Kellogg, Naren Ramakrishnan

Correspondence identifies relationships among objects via similarities among their components; it is ubiquitous in the analysis of spatial datasets, including images, weather maps, and computational simulations. This paper develops a novel multi-level mechanism for qualitative analysis of correspondence. Operators leverage domain knowledge to establish corre

Pawel Wocjan, Dominik Janzing, Thomas Beth

Learning joint probability distributions on n random variables requires exponential sample size in the generic case. Here we consider the case that a temporal (or causal) order of the variables is known and that the (unknown) graph of causal dependencies has bounded in-degree Delta. Then the joint measure is uniquely determined by the probabilities of all (2

Magnus Boman, Stefan Johansson, David Lyback

On markets with receding prices, artificial noise traders may consider alternatives to buy-and-hold. By simulating variations of the Parrondo strategy, using real data from the Swedish stock market, we produce first indications of a buy-low-sell-random Parrondo variation outperforming buy-and-hold. Subject to our assumptions, buy-low-sell-random also outperf

Thomas Eiter, Georg Gottlob, Kazuhisa Makino

We consider the problem of dualizing a monotone CNF (equivalently, computing all minimal transversals of a hypergraph), whose associated decision problem is a prominent open problem in NP-completeness. We present a number of new polynomial time resp. output-polynomial time results for significant cases, which largely advance the tractability frontier and imp

E. Menendez-Proupin, Nana Cabo-Bisset

The adiabatic theory of resonance one-phonon Raman scattering in semiconductor nanocrystals is revised and extended with perturbative non-adiabatic corrections, given by the Albrecht&#39;s B term. This theory is confronted with the time-dependent perturbation approach, pointing at their differences and similarities. It is shown that both theories are equival

Angel J. Garcia-Adeva, Dylan R. Conradson, Phillip Villella, Steven D. Conradson

The effects of periodic and aperiodic distortions on the structure factor and radial distribution function of single-component lattices are investigated. To this end, different kinds of distortions are applied to the otherwise perfect square lattice and the corresponding radial distribution function and structure factor for the resulting lattices are calcula

Weidong Sheng, Jean-Pierre Leburton

We report significant deviations from the usual quadratic dependence of the ground state interband transition energy on applied electric fields in InAs/GaAs self-assembled quantum dots. In particular, we show that conventional second-order perturbation theory fails to correctly describe the Stark shift for electric field below $F = 10$ kV/cm in high dots. Ei

Nizam A. Taylanov, G. R. Berdiyorov

Nonlinear dynamics of the thermal and electromagnetic instabilities of the mixed state in type II superconductors has been analysed taking into account the effect of dissipation and dispersion. The existence of nonlinear running waves describing the final stage of evolution of the thermomagnetic instability in superconductors is demonstrated analytically.

Klaus Kassner, Chaouqi Misbah

We derive amplitude equations for interface dynamics in pattern forming systems with long-range interactions. The basic condition for the applicability of the method developed here is that the bulk equations are linear and solvable by integral transforms. We arrive at the interface equation via long-wave asymptotics. As an example, we treat the Grinfeld inst

Gianluca Stefanucci, Michele Cini

As a prototype model of antiferromagnetism, we propose a repulsive Hubbard Hamiltonian defined on a graph $Ł={\cal A}\cup{\cal B}$ with ${\cal A}\cap {\cal B}=\emptyset$ and bonds connecting any element of ${\cal A}$ with all the elements of ${\cal B}$. Since all the hopping matrix elements associated with each bond are equal, the model is invariant under an

G. Cristofano, G. Maiella, V. Marotta, G. Niccoli

We analyze the modular properties of the effective CFT description for paired states, proposed in cond-mat/0003453, corresponding to the non-standard filling nu =1/(p+1). We construct its characters for the twisted and the untwisted sector and the diagonal partition function. We show that the degrees of freedom entering our partition function naturally go to

A. G. Zawadowski, R. Karadi, J. Kertesz

In this paper we compare market price fluctuations with the response to fundamental price drops within the Lux-Marchesi model which is able to reproduce the most important stylized facts of real market data. Major differences can be observed between the decay of spontaneous fluctuations and of changes due to external perturbations reflecting the absence of d

Tanya Araujo, R. Vilela Mendes, João Seixas

Small-world (SW) networks have been identified in many different fields. Topological coefficients like the clustering coefficient and the characteristic path length have been used in the past for a qualitative characterization of these networks. Here a dynamical approach is used to characterize the small-world phenomenon. Using the $β-$model, a coupled map d

R. Mahmoodi, S. N. Shevchenko, Yu. A. Kolesnichenko

A stationary Josephson effect in point contacts between triplet superconductors is analyzed theoretically for most probable models of the order parameter in UPt_{3} and Sr_{2}RuO_{4}. The consequence of misorientation of crystals in superconducting banks on this effect is considered. We show that different models for the order parameter lead to quite differe

Wu Junling, Baigeng Wang, Jian Wang

We have developed a general theory for a parametric pump consisting of a nonmagnetic system with two ferromagnetic leads whose magnetic moments orient at an angle $θ$ with respect to each other. In this theory, the leads can maintain at different chemical potential. As a result, the current is driven due to both the external bias and the pumping potentials.

Peter Teuben

Like hardware, evolution of software has had a major impact on the field of particle simulations. This paper illustrates how simulation software has evolved, and where it can go. In addition, with the various ongoing Virtual Observatory efforts, producers of theory data should think more about sharing their data! Some examples are given of what we can do wit

John J. Feldmeier, J. Christopher Mihos, Heather L. Morrison, Stephen A. Rodney

We report the initial results of a deep imaging survey of galaxy clusters. The primary goals of this survey are to quantify the amount of intracluster light as a function of cluster properties, and to quantify the frequency of tidal debris. We outline the techniques needed to perform such a survey, and we report findings for the first two galaxy clusters in

Christopher R. Eck, John J. Cowan, David Branch

We report VLA radio observations of 29 SNe with ages ranging from 10 days to about 90 years past explosion. These observations significantly contribute to the existing data pool on such objects. Included are detections of known radio SNe~1950B, 1957D, 1970G, 1983N, the suspected radio SN 1923A, and the possible radio SN 1961V. None of the remaining 23 observ

C. McCabe, G. Duchene, A. M. Ghez

We present deep, near-infrared images of the circumbinary disk surrounding the pre-main-sequence binary star, GG Tau A, obtained with NICMOS aboard the Hubble Space Telescope. The spatially resolved proto-planetary disk scatters roughly 1.5% of the stellar flux, with a near-to-far side flux ratio of ~1.4, independent of wavelength, and colors that are compar

J. V. Smoker, F. P. Keenan, N. Lehner, C. Trundle

We present echelle spectrograph observations in NaD, at resolutions of 6.2-8.5 km/s, for 11 stars located in the line-of-sight to the M15 intermediate velocity cloud, which has a radial velocity of 70 km/s. This cloud is a part of IVC Complex gp. The targets range in magnitude from V=13.3-14.8. Seven of the observed stars are in the M15 globular cluster, the