June 2002 arXiv papers — page 17

Mikhail V. Ivanov

Precise solutions of the Hartree-Fock equations for the ground state of the hydrogen molecule are obtained for a wide range of internuclear distances R by means of a two-dimensional fully numerical mesh computational method. The spatial parts of the single-electron wave functions are found to be coinciding for R<2.30a.u. At larger distances they become diffe

Er&#39;el Granot, Shmuel Sternklar

The maximum bit-rate of a slab waveguide is ultimately determined by the waveguide dispersion. We show that while the maximum bit rate in a waveguide is inversely proportional to the waveguide&#39;s width, bit rate per unit width (i.e., spatial capacity) decreases, and in the limit of a zero-width waveguide it converges to a value, which is independent of th

STAR Collaboration

Mid-rapidity transverse mass spectra and multiplicity densities of charged and neutral kaons are reported for Au+Au collisions at $\snn$=130 GeV at RHIC. The spectra are exponential in transverse mass, with an inverse slope of about 280 MeV in central collisions. The multiplicity densities for these particles scale with the negative hadron pseudo-rapidity de

Adilson E. Motter, Ying-Cheng Lai

A topological bifurcation in chaotic scattering is characterized by a sudden change in the topology of the infinite set of unstable periodic orbits embedded in the underlying chaotic invariant set. We uncover a scaling law for the fractal dimension of the chaotic set for such a bifurcation. Our analysis and numerical computations in both two- and three-degre

Y. Hiraoka, Y. Kodama

We present a review of the normal form theory for weakly dispersive nonlinear wave equations where the leading order phenomena can be described by the KdV equation. This is an infinite dimensional extension of the well-known Poincaré-Dulac normal form theory for ordinary differential equations. We also provide a detailed analysis of the interaction problem o

K. B. Blyuss

In this work the Melnikov method for perturbed Hamiltonian wave equations is considered in order to determine possible chaotic behaviour in the systems. The backbone of the analysis is the multi-symplectic formulation of the unperturbed PDE and its further reduction to travelling waves. In the multi-symplectic approach two separate symplectic operators are i

K. B. Blyuss

Stationary wave solutions of the perturbed Korteweg-de Vries equation are considered in the presence of external hamiltonian perturbations. Conditions of their chaotic behaviour are studied with the help of Melnikov theory. For the homoclinic chaos Poincaré sections are constructed to demonstrate the complicated behaviour, and Lyapunov exponents are also num

Atsushi Nagai

A new type of an integrable mapping is presented. This map is equipped with fractional difference and possesses an exact solution, which can be regarded as a discrete analogue of the Mittag-Leffler function.

A. Pogrebkov

Realizing bosonic field v(x) as current of massless (chiral) fermions we derive hierarchy of quantum polynomial interactions of the field v(x) that are completely integrable and lead to linear evolutions for the fermionic field. It is proved that in the classical limit this hierarchy reduces to the dispersionless KdV hierarchy. Application of our constructio

Peter Schupp

Contents: 1 Frustrated quantum spin systems 1.1 The Pyrochlore checkerboard 1.2 Singlets in reflection symmetric spin systems 2 Wehrl entropy of Bloch coherent states 2.1 Conjectures of Wehrl and Lieb 2.2 Proof of Lieb&#39;s conjecture for low spin 3 Symmetries of the Hubbard model 4 Quantum integrable systems 4.1 Twisted quantum Lax equations 4.2 Face algeb

Vladimir Buslaev, Alexander Fedotov

In this paper, we study entire solutions of the difference equation $ψ(z+h)=M(z)ψ(z)$, $z\in{\mathbb C}$, $ψ(z)\in {\mathbb C}^2$. In this equation, $h$ is a fixed positive parameter and $M: {\mathbb C}\to SL(2,{\mathbb C})$ is a given matrix function. We assume that $M(z)$ is a $2π$-periodic trigonometric polynomial. We construct the minimal entire solution

F. Bentosela, Ph. Briet, L. Pastur

We study the discrete Schrödinger operator $H$ in $\ZZ^d$ with the surface potential of the form $V(x)=g δ(x_1) \tan π(α\cdot x_2+ ω)$, where for $x \in \ZZ^d$ we write $x=(x_1,x_2), \quad x_1 \in \ZZ^{d_1}, x_2 \in \mathbb{Z}^{d_2}, α\in \R^{d_2}, ω\in [0,1)$. We first consider the case where the components of the vector $α$ are rationally independent, i.e.

Michael K. Kinyon, J. D. Phillips

The purpose of this brief note is to sharpen a result of Kepka about the axiomization of the variety of trimedial quasigroups.

Michael Atiyah, Jurgen Berndt

A classical result asserts that the complex projective plane modulo complex conjugation is the 4-dimensional sphere. We generalize this result in two directions by considering the projective planes over the normed real division algebras and by considering the complexifications of these four projective planes.

R. Carmona, L. Koralov, S. Molchanov

We find the asymptotics for the almost sure Lyapunov exponent for the solution of the parabolic Anderson problem as the molecular diffusivity tends to zero.

David Angeli, Eduardo D. Sontag

Monotone systems constitute one of the most important classes of dynamical systems used in mathematical biology modeling. The objective of this paper is to extend the notion of monotonicity to systems with inputs and outputs, a necessary first step in trying to understand interconnections, especially including feedback loops, built up out of monotone compone

Igor V. Dolgachev

We study families of elliptic curves of degree n+1 in $P^n$ containing a fixed set of m points. In the case m = n+3 we show that this family is birationally isomorphic to a smooth complete intersection of n-2 diagonal quadrics in $P^{n+2}$. We also describe an action of the 2-elementary abelian group $2^{n+2}$ on this family via Cremona transformations in $P

Stephen L. Adler

We consider the classical dynamics of bosonic and fermionic matrix variables in complex Hilbert space, defined by a trace action, assuming cyclic invariance under the trace and the presence of a global unitary invariance. With plausible and explicitly stated assumptions, including the existence of a large hierarchy of scale between the underlying dynamics an

T. Banks

I present a heuristic calculation of the critical exponent relating the gravitino mass to the cosmological constant in a de Sitter universe. The ingredients for the calculation are the area law for entropy, an R symmetry of the low energy effective Lagrangian, and a crude picture of the degenerate levels of the cosmological horizon.

M. Axenides, E. G. Floratos, L. Perivolaropoulos

In the lightcone frame, where the supermembrane theory and the Matrix model are strikingly similar, the equations of motion admit an elegant complexification in even dimensional spaces. Although the explicit rotational symmetry of the target space is lost, the remaining unitary symmetries apart from providing a simple and unifying description of all known so

E. Elizalde, F. C. Santos, A. C. Tort

We evaluate the fermionic Casimir effect associated with a massive fermion confined within a planar (d+1) dimensional slab-bag, on which MIT bag model boundary conditions of standard type, along a single spatial direction, are imposed. A simple and effective method for adding up the zero-point energy eigenvalues, corresponding to a quantum field under the in

R. E. Browne, J. A. Gracey

Massive quarks are included in the Curci-Ferrari model and the theory is renormalized at two loops in the MSbar scheme in an arbitrary covariant gauge.

Gregory Gabadadze, M. Shifman

A deeper understanding of the vacuum structure in QCD invites one to rethink certain aspects of the axion physics. The recent advances are mostly due to developments in supersymmetric gauge theories and the brane theory, in which QCD can be embedded. They include, but are not limited to, the studies of metastable vacua in multicolor gluodynamics, and the dom

Laura Covi, Leszek Roszkowski, Michael Small

We investigate the role of an effective dimension-4 axino-quark-squark coupling in the thermal processes producing stable cold axino relics in the early Universe. We find that, while the induced squark and quark scattering processes are always negligible, squark decays become important in the case of low reheat temperature and large gluino mass. The effect c

S. Munier

Through an analysis of diffractive vector meson production, we show that the proton appears quite dense to a small size probe at present HERA energies. This means that saturation effects are already important.

Stefano Bertolini

I shortly review the present status of the theoretical calculations of eps&#39;/eps and the comparison with the present experimental results. I discuss the role of higher order chiral corrections and in general of non-factorizable contributions for the explanation of the Delta I = 1/2 selection rule and direct CP violation in kaon decays. Still lacking satis

Peter Orland

The first and second Griffiths inequalities are proved for some classical O($n$)-invariant spin models (including Euclidean quantum field theories) for any $n$. The proof assumes a certain condition on an integral transform of the measure. Some examples are discussed.

S. Ahmed, CLEO Collaboration

We present new measurements of branching fractions for the color-favored decays B^- --> D^0 pi^- and Bbar^0 --> D^+ pi^-. Using 9.67 x 10^6 BBbar pairs collected with the CLEO detector, we obtain the branching fractions BR(B^- --> D^0 pi^- =3D (49.7 +/- 1.2 +/- 2.9 +/- 2.2) x 10^{-4} and BR(Bbar^0 --> D^+ pi^- =3D (26.8 +/- 1.2 +/- 2.4 +/- 1.2) x 10^{-4}. Th

Alberto Lobo, Massimo Cerdonio, Alvaro Montero

This paper analyses in quantitative detail the effect caused by a moving mass on a spherical gravitational wave detector. This applies to situations where heavy traffic or similar disturbances happen near the GW antenna. Such disturbances result in quadrupole tidal stresses in the antenna mass, and they therefore precisely fake a real gravitational signal. T

Thomas Thiemann

Recently, substantial amount of activity in Quantum General Relativity (QGR) has focussed on the semiclassical analysis of the theory. In this paper we want to comment on two such developments: 1) Polymer-like states for Maxwell theory and linearized gravity constructed by Varadarajan which use much of the Hilbert space machinery that has proved useful in QG

Vladimir Gudkov, Joseph E. Johnson

An approach for real-time network monitoring in terms of numerical time-dependant functions of protocol parameters is suggested. Applying complex systems theory for information f{l}ow analysis of networks, the information traffic is described as a trajectory in multi-dimensional parameter-time space with about 10-12 dimensions. The network traffic descriptio

Weiping Zhang, Han Pu, Chris P. Search, Pierre Meystre

A nonlinear Schrödinger equation is derived for the dynamics of a beam of ultracold fermionic atoms traversing a Bose-Einstein condensate. The condensate phonon modes are shown to provide a nonlinear medium for the fermionic atoms. A two-fermion bound state is predicted to arise, and the signature of the bound state in a nonlinear atom optics experiment is d

C. D. Santangelo, P. Pincus

Myelin figures are densely packed stacks of coaxial cylindrical bilayers that are unstable to the formation of coils or double helices. These myelin figures appear to have no intrinsic chirality. We show that such cylindrical membrane stacks can develop an instability when they acquire a spontaneous curvature or when the equilibrium distance between membrane

Smitha Vishveshwara, Cristina Bena, Leon Balents, Matthew P. A. Fisher

We investigate the effect of interactions on Andreev current at a normal-superconducting junction when the normal phase is a Luttinger liquid with repulsive interactions. In particular, we study the system of a finite sized carbon nanotube placed between one metallic and one superconducting lead. We show that interactions and finite size effects give rise to

D. Blume

The diffusion quantum Monte Carlo technique is used to solve the many-body Schroedinger equation fully quantum mechanically and nonperturbatively for bosonic atomic gases in cigar-shaped confining potentials. By varying the aspect ratio of the confining potential from 1 (spherical trap) to 10000 (highly elongated trap), we characterize the transition from th

M. P. Almeida, F. Q. Potiguar, U. M. S. Costa

It is presented a microscopic interpretation for the temperature within Tsallis thermostatistics, generalizing the classical derivation based on the Boltzmann-Gibbs statistics. It is shown that with this definition the zeroth law and the equipartition theorem are valid in their classical form. Moreover, it is observed that the equation of state for an ideal

S. Cocco, R. Monasson

The analysis of the solving complexity of random 3-SAT instances using the Davis-Putnam-Loveland-Logemann (DPLL) algorithm slightly below threshold is presented. While finding a solution for such instances demands exponential effort with high probability, we show that an exponentially small fraction of resolutions require a computation scaling linearly in th

A. Carpio, L. L. Bonilla

Propagation of pulses in myelinated fibers may be described by appropriate solutions of spatially discrete FitzHugh-Nagumo systems. In these systems, propagation failure may occur if either the coupling between nodes is not strong enough or the recovery is too fast. We give an asymptotic construction of pulses for spatially discrete FitzHugh-Nagumo systems w

X. Guardiola, R. Guimera, A. Arenas, A. Diaz-Guilera

A challenging problem in the social sciences is the characterization of the formation of ``social capital&#39;&#39;. It is believed that societies with more social capital are more democratic and economically developed than societies with little social capital. However, social capital is a concept hard to quantify and measure in a ``real-word&#39;&#39; conte

S. Cocco, J. F. Marko, R. Monasson

We review statistical-mechanical theories of single-molecule micromanipulation experiments on nucleic acids. First, models for describing polymer elasticity are introduced. We then review how these models are used to interpret single-molecule force-extension experiments on single-stranded and double-stranded DNA. Depending on the force and the molecules used

R. Folch, M. Plapp

We develop a phase-field model of eutectic growth that uses three phase fields, admits strictly binary interfaces as stable solutions, and has a smooth free energy functional. We use this model to simulate oscillatory limit cycles in two-dimensional lamellar growth, and find a continuous evolution from low-amplitude oscillations to successive invasions of on

German Drazer, Boris Khusid, Joel Koplik, Andreas Acrivos

Using molecular dynamics simulations, we study the motion of a closely fitting nanometer-size solid sphere in a fluid-filled cylindrical nanochannel at low Reynolds numbers and for a wide range of fluid-solid interactions corresponding to different wetting situations. For fluids that are not completely wetting we observe an interesting and novel adsorption p

N. Katz, J. Steinhauer, R. Ozeri, N. Davidson

We report a measurement of the suppression of collisions of quasi-particles with ground state atoms within a Bose-Einstein condensate at low momentum. These collisions correspond to Beliaev damping of the excitations, in the previously unexplored regime of the continuous quasi-particle energy spectrum. We use a hydrodynamic simulation of the expansion dynami

F. Gomory, R. Tebano, A. Sanchez, E. Pardo

The case of a hard type II superconductor in the form of strip with elliptic cross-section when placed in transverse magnetic field is studied. We approach the problem in two steps, both based on the critical-state model. First we calculate numerically the penetrated current profiles that ensure complete shielding in the interior, without assuming an a prior

Michael L. Hart, David Lamper, Neil F. Johnson

Complex systems can exhibit unexpected large changes, e.g. a crash in a financial market. We examine the large endogenous changes arising within a non-trivial generalization of the Minority Game: the Grand Canonical Minority Game (GCMG). Using a Markov Chain description, we study the many possible paths the system may take. This `many-worlds&#39; view not on

A. Wallraff, T. Duty, A. Lukashenko, A. V. Ustinov

The escape of a small current-biased Josephson tunnel junction from the zero voltage state in the presence of weak microwave radiation is investigated experimentally at low temperatures. The measurements of the junction switching current distribution indicate the macroscopic quantum tunneling of the phase below a cross-over temperature of $T^{\star} \approx

S. Rogge, M. Durkut, T. M. Klapwijk

Thin films of potassium doped C60, an organic semiconductor, have been grown on silicon. The films were grown in ultra-high vacuum by thermal evaporation of C60 onto oxide-terminated silicon as well as reconstructed Si(111). The substrate termination had a drastic influence on the C60 growth mode which is directly reflected in the electrical properties of th

A. E. Nikiforov, A. Yu. Zaharov, V. A. Chernyshev, M. Yu. Ougrumov

Within the framework of the virtual crystal method implemented in the shell model and pair potential approximation the crystal structure of mixed fluorites Ca(1-x)Sr(x)F(2) and Sr(1-x)Ba(x)F(2) has been calculated. The impurity center Eu(2+) and the distance Eu(2+)-F in this crystals have been also calculated. The low level position of excited 4f65d configur

Rene Messina

The effects of image charges (i.e., induced surface charges of polarization) in spherical geometry and their implication for charged colloidal systems are investigated. We study analytically and exactly a single microion interacting with a dielectric sphere and discuss the similarities and discrepancies with the case of a planar interface. By means of extens

C. E. Yasin, M. Y. Simmons, A. R. Hamilton, N. E. Lumpkin

We investigate the relationship between the quantum Hall extended states and the apparent B=0 `metal&#39;-insulator transition in extremely low density, high quality two-dimensional n-GaAs systems (μ_{peak} ~ 2 x 10^7 cm^2/Vs). The combination of small effective mass and high quality allow us to resolve the continued floating up in energy of the extended sta

Patrick B. Warren

A simple extension of existing models for protein crystallisation is described, in which salt ions and charge neutrality are explicitly incorporated. This provides a straightforward explanation for the shape of protein crystallisation boundaries, the associated scaling properties seen for lysozyme, and can also explain much of the salt dependence of the seco

Sara Seager, Gabriela Mallen-Ornelas

There is a unique solution of the planet and star parameters from a planet transit light curve with two or more transits if the planet has a circular orbit and the light curve is observed in a band pass where limb darkening is negligible. The existence of this unique solution is very useful for current planet transit surveys for several reasons. First, there

K. Rines, M. J. Geller, A. Diaferio, A. Mahdavi

Using a redshift survey of 1323 galaxies (1092 new or remeasured) in a region of 95 square degrees centered on the nearby galaxy cluster Abell 2199, we analyze the supercluster containing A2199, A2197, and an X-ray group. The caustic technique accurately reproduces the true mass profiles of simulated simple superclusters (i.e., superclusters where the virial

Michael A. Strauss, David H. Weinberg, Robert H. Lupton, Vijay K. Narayanan

We describe the algorithm that selects the main sample of galaxies for spectroscopy in the Sloan Digital Sky Survey from the photometric data obtained by the imaging survey. Galaxy photometric properties are measured using the Petrosian magnitude system, which measures flux in apertures determined by the shape of the surface brightness profile. The metric ap

D. Jain, A. Dev, J. S. Alcaniz

Brane world cosmologies seem to provide an alternative explanation for the present accelerated stage of the Universe with no need to invoke either a cosmological constant or an exotic \emph{quintessence} component. In this paper we investigate statistical properties of gravitational lenses for some particular scenarios based on this large scale modification

T. J. Turner, R. F. Mushotzky, T. Yaqoob, I. M. George

We present results from a simultaneous Chandra HETG and XMM-Newton observation of NGC 3516. We find evidence for several narrow components of Fe Kalpha along with a broad line. We consider the possibility that the lines arise in an blob of material ejected from the nucleus with velocity ~0.25c. We also consider an origin in a neutral accretion disk, sufferin

Laura Ferrarese, David Merritt

After a brief historical introduction, we summarize current efforts and accomplishments in the study of supermassive black holes.

Arunav Kundu, Tom Maccarone, Steve Zepf

We have analyzed the low mass X-ray binary (LMXB) candidates in a Chandra observation of the giant elliptical galaxy NGC 4472. In a region observed by the Hubble Space Telescope, approximately 40% of the bright (L_X >= 10^37 ergs/s) LMXBs are associated with optically identified globular clusters (GC). This is significantly higher than the fraction of bright

F. Camilo, D. R. Lorimer, N. D. R. Bhat, E. V. Gotthelf

We report the discovery of a pulsar with period P = 136 ms and dispersion measure 308 pc/cc in a deep observation of the supernova remnant (SNR) G54.1+0.3 with the Arecibo radio telescope. Timing measurements of the new pulsar, J1930+1852, reveal a characteristic age of Pdt/2dP = 2900 yr and spin-down luminosity dE/dt = 1.2e37 erg/s. We have subsequently sea

P. F. Weck, A. Schweitzer, P. C. Stancil, P. H. Hauschildt

A new, complete, theoretical rotational and vibrational line list for the A-X electronic transition in MgH is presented. The list includes transition energies and oscillator strengths for all possible allowed transitions and was computed using the best available theoretical potential energies and dipole transition moment function with the former adjusted to

Guillaume Dubus

Accretion onto a compact object must occur through a disc when the material has some initial angular momentum. Thin discs and the thicker low radiative efficiency accretion flows are solutions to this problem that have been widely studied and applied. This is an introduction to these accretion flows within the context of X-ray binaries and cataclysmic variab

Nickolay Y. Gnedin, Sergei F. Shandarin

We show how the morphological analysis of the maps of the secondary CMB anisotropies can detect an extended period of ``smoldering&#39;&#39; reionization, during which the universe remains partially ionized. Neither radio observations of the redshifted 21cm line nor IR observations of the redshifted Lyman-alpha forest will be able to detect such a period. Th

Hugh R. A. Jones, R. Paul Butler, Geoffrey W. Marcy, Chris G. Tinney

We report precise Doppler measurements of the stars HD 216437, HD 196050 and HD 160691 obtained with the Anglo-Australian Telescope using the UCLES spectrometer together with an iodine cell as part of the Anglo-Australian Planet Search. Our measurements reveal periodic Keplerian velocity variations that we interpret as evidence for planets in orbit around th

R. A. Laing, A. H. Bridle

We show that the principal differences in appearance of the main and counter-jets within 30 arcsec of the nucleus of the low-luminosity radio galaxy 3C 31 can result entirely from the effects of relativistic aberration in two symmetrical, antiparallel, axisymmetric, time-stationary relativistic flows. We develop empirical parameterized models of the jet geom

G. Fritz Benedict, B. E. McArthur, L. W. Fredrick, T. E. Harrison

We present an absolute parallax and relative proper motion for the fundamental distance scale calibrator, delta Cep. We obtain these with astrometric data from FGS 3, a white-light interferometer on HST. Utilizing spectrophotometric estimates of the absolute parallaxes of our astrometric reference stars and constraining delta Cep and reference star HD 213307

N. C. Santos, M. Mayor, D. Naef, F. Pepe

In this article we present the case of HD 41004 AB, a system composed of a K0V star and a 3.7-magnitude fainter M-dwarf companion separated by only 0.5 arcsec. An analysis of CORALIE radial-velocity measurements has revealed a variation with an amplitude of about 50m/s and a periodicity of 1.3days. This radial-velocity signal is consistent with the expected

K. Manolakou, J. G. Kirk

The spectral evolution of powerful double radio galaxies (FR II&#39;s) is thought to be determined by the acceleration of electrons at the termination shock of the jet, their transport through the bright head region into the lobes and the production of the radio emission by synchrotron radiation in the lobes. Models presented to date incorporate some of thes

Shaul Hanany, Daniel P. Marrone

We compare the diffraction-limited field of view (FOV) provided by four types of off-axis Gregorian telescopes: the classical Gregorian, the aplanatic Gregorian, and designs that cancel astigmatism and both astigmatism and coma. The analysis is carried out using telescope parameters that are appropriate for satellite and balloon-borne millimeter and sub-mill

D. Apai, I. Pascucci, Th. Henning, M. F. Sterzik

We present the first mid-infrared (MIR) detection of a field brown dwarf (BD) and the first ground-based MIR measurements of a disk around a young BD candidate. We prove the absence of warm dust surrounding the field BD LP 944-20. In the case of the young BD candidate Cha Ha2, we find clear evidence for thermal dust emission from a disk. Surprisingly, the ob

C. D. Rimes, E. van Kampen

We present a phenomenological model for understanding the origins and evolution of galaxy morphologies from a phenomenological perspective. The model includes an observationally motivated prescription for star formation in galaxy disks, as well as a merger-driven starburst mode of star formation. We consider the formation of bulges and ellipticals both in me

Kenji Bekki, Kenneth C. Freeman

The HI disk of the blue compact dwarf (BCD) galaxy NGC 2915 extends to 22 optical scalelengths and shows spiral arms reaching far beyond the optical component. None of the previous theories for spiral structure provide likely explanations for these very extended spiral arms. Our numerical simulations first demonstrate that such large spiral arms can form in

Kenji Bekki, Yasuhiro Shioya, Warrick J. Couch

Recent spectroscopic and high resolution $HST$-imaging observations have revealed significant numbers of ``passive&#39;&#39; spiral galaxies in distant clusters, with all the morphological hallmarks of a spiral galaxy (in particular, spiral arm structure), but with weak or absent star formation. Exactly how such spiral galaxies formed and whether they are th

E. Antonello

A short analysis is presented of the effects on the cepheid light curve shape, i.e. on the Fourier parameters usually adopted for its description, of the blending of the stellar image with other close stars. The conclusion is that, within reasonable error, the effects are in general small and the Fourier decomposition is confirmed to be a useful tool for pul

Felix Ryde, Vahe Petrosian

Several patterns have been discovered in how some spectral characteristics change during the decaying phase of long (> few s.) GRB pulses. We compare these observed signatures with those expected from a relativistically expanding shell. Within the internal shock model and assuming a short cooling time, we show that the angular dependence in arrival time can

A. J. Castro-Tirado, J. M. Castro Cerón, J. Gorosabel, P. Pata

We imaged the error box of a gamma-ray burst of the short (0.5 s), hard type (GRB 000313), with the BOOTES-1 experiment in southern Spain, starting 4 min after the gamma-ray event, in the I-band. A bright optical transient (OT 000313) with I = 9.4 +/- 0.1 was found in the BOOTES-1 image, close to the error box (3-sigma) provided by BATSE. Late time VRIK&#39;

Daniel E. Sheehy

In this work the connection between vortex condensation in a d-wave superconductor and the QED$_3$ gauge theory of the pseudogap is elucidated. The approach taken circumvents the use of the standard Franz-Tesanovic gauge transformation, borrowing ideas from the path-integral analysis of the Aharonov-Bohm problem. An essential feature of this approach is that

Tapobrata Sarkar

We study non-supersymmetric orbifold singularities from the point of view of D-brane probes. We present a description of the decay of such singularities from considerations of the toric geometry of the probe branes.

Silas R. Beane, Martin J. Savage

The dependence of the nuclear force on standard model parameters plays an important role in bounding time and space variations of fundamental couplings over cosmological time scales. We discuss the quark-mass dependence of deuteron and di-neutron binding in a systematic chiral expansion. The leading quark-mass dependence of the nuclear force arises from one-

Christos Kokorelis

We construct six stack D6-brane vacua (non-supersymmetric) that have at low energy exactly the standard model (with right handed neutrinos). The construction is based on D6-branes intersecting at angles in $D = 4$ type toroidal orientifolds of type I strings. Three U(1)&#39;s become massive through their couplings to RR fields and from the three surviving ma

Hessam Hamidi-Tehrani

Let Gamma be a group generated by two positive multi-twists. We give some sufficient conditions for Gamma to be free or have no `unexpectedly reducible&#39; elements. For a group Gamma generated by two Dehn twists, we classify the elements in Gamma which are multi-twists. As a consequence we are able to list all the lantern-like relations in the mapping clas

Lee Lindblom, Mark A. Scheel

The Einstein evolution equations may be written in a variety of equivalent analytical forms, but numerical solutions of these different formulations display a wide range of growth rates for constraint violations. For symmetric hyperbolic formulations of the equations, an exact expression for the growth rate is derived using an energy norm. This expression ag

Stephen G. Naculich, Howard J. Schnitzer, Niclas Wyllard

We study the pp-wave limits of various elliptic models with orientifold planes and D7-branes, as well as the pp-wave limit of an orientifold of adS_5 x T^{11}. Many of the limits contain both open and closed strings. We also present pp-wave limits of theories which give rise to a compact null direction and contain open strings. Maps between the string theory

Marco Matone, Luca Mazzucato, Ichiro Oda, Dmitri Sorokin

We show that the pure spinor formalism proposed by Berkovits to covariantly quantize superstrings is a gauge fixed, twisted version of the complexified n=2 superembedding formulation of the superstring. This provides the Berkovits approach with a geometrical superdiffeomorphism invariant ground. As a consequence, the absence of the worldsheet (super)diffeomo

Urbano Franca, Rogerio Rosenfeld

We explore regions of parameter space in a simple exponential model of the form $V = V_0 e^{- λ\frac{Q}{M_p}}$ that are allowed by observational constraints. We find that the level of fine tuning in these models is not different from more sophisticated models of dark energy. We study a transient regime where the parameter $λ$ has to be less than $\sqrt{3}$ a

Christof Zalka, Todd A. Brun

This is a comment on a recent publication claiming to have found a ``quantum optimization&#39;&#39; algorithm which outperforms known algorithms for minimizing some ``cost function&#39;&#39;. Unfortunately, this algorithm is no better than choosing a state at random and checking whether it has low cost.

Almut Beige, Jiannis Pachos, Herbert Walther

Motivated by a recent experiment [J. Eschner {\it et al.}, Nature {\bf 413}, 495 (2001)], we now present a theoretical study on the fluorescence of an atom in front of a mirror. On the assumption that the presence of the distant mirror and a lens imposes boundary conditions on the electric field in a plane close to the atom, we derive the intensities of the

James Isenberg, Rafe Mazzeo, Daniel Pollack

We prove that there are no restrictions on the spatial topology of asymptotically flat solutions of the vacuum Einstein equations in (n+1)-dimensions. We do this by gluing a solution of the vacuum constraint equations on an arbitrary compact manifold to an asymptotically Euclidean solution of the constraints on R^n. For any compact manifold which does not ad

John Ellis, Junji Hisano, Martti Raidal, Yasuhiro Shimizu

We present a new parametrization of the minimal seesaw model, expressing the heavy-singlet neutrino Dirac Yukawa couplings $(Y_ν)_{ij}$ and Majorana masses $M_{N_i}$ in terms of effective light-neutrino observables and an auxiliary Hermitian matrix $H.$ In the minimal supersymmetric version of the seesaw model, the latter can be related directly to other low

Robert D. Klauber

The experimentally determined Sagnac fringe shift dependency on angular velocity and enclosed area is derived from the rotating reference frame using non-time-orthogonal tensor analysis. The relationship for the most general case, in which the area enclosed is not circular and does not have the axis of rotation passing through its center, is determined. It i

K. A. Bugaev, M. Gazdzicki, M. I. Gorenstein

The transverse mass spectra of J/psi and psi&#39; mesons and Omega hyperons produced in central Au+Au collisions at RHIC energies are discussed within a statistical model used successfully for the interpretation of the SPS results. The comparison of the presented model with the future RHIC data should serve as a further crucial test of the hypothesis of stat

Pieter-Jan De Smet

We give a Petrov classification for five-dimensional metrics. We classify Ricci-flat metrics that are static, have an SO(3) isometry group and have Petrov type 22. We use this classification to look for the metric of a black hole on a cylinder, i.e. a black hole with asymptotic geometry four-dimensional Minkowski space times a circle. Although a black string

Jairo Bochi

We prove three inequalities relating some invariants of sets of matrices, such as the joint spectral radius. One of the inequalities, in which proof we use geometric invariant theory, has the generalized spectral radius theorem of Berger and Wang as an immediate corollary.

Iacopo Carusotto, Yvan Castin

Recently, a Quantum Monte Carlo method alternative to the Path Integral Monte Carlo method was developed for the numerical solution of the N-boson problem; it is based on the stochastic evolution of classical fields. Here we apply it to obtain exact results for the occupation statistics of the condensate mode in a weakly interacting trapped one-dimensional B

Fabio L. Braghin

The linear sigma model with pions and sigma coupled to baryons and a (massive) gauge vector meson is considered for the description of a finite baryonic density system. The stability equation for the bound system is studied in the homogeneous limit considering quantum fluctuations for the scalar and pseudo scalar fields within a variational method with trunc

Gautam Mandal, Nemani V. Suryanarayana, Spenta R. Wadia

We find an infinite number of conserved currents and charges in the semiclassical limit $λ\to \infty$ of string theory in AdS$_5 \times S^5$ and remark on their relevance to conserved charges in the dual gauge theory. We establish a general procedure of exploring the semiclassical limit by viewing the classical motion as collective motion in the relevant par

A. Rousseau, E. Teboul, N. Lang, M. Hannemann

Langmuir probe techniques have been used to study time and spatially resolved electron densities and electron temperatures in pulse-modulated hydrogen discharges in two different planar microwave reactors (fmicrowave= 2.45 GHz, tpulse= 1 ms). The reactors are (i) a standing-wave radiative slotted waveguide reactor and (ii) a modified travelling-wave radiativ

J. H. Jefferson, M. Fearn, D. L. J. Tipton, T. P. Spiller

We show that two electrons confined in a square semiconductor quantum dot have two isolated low-lying energy eigenstates, which have the potential to form the basis of scalable computing elements (qubits). Initialisation, one-qubit and two-qubit universal gates, and readout are performed using electrostatic gates and magnetic fields. Two-qubit transformation

Francisco Guinea, Robert S. Markiewicz, Maria A. H. Vozmediano

The Kohn-Luttinger mechanism for superconductivity is investigated in a model for the electron doped cuprates. The symmetry of the order parameter of the superconducting phase is determined as a function of the geometry of the Fermi surface together with the structure of the electron-hole susceptibility. It is found to remain d_{x^2-y^2} wave within a large

Guray Erkol, Gursevil Turan

We investigate the CP violating asymmetry, the forward backward asymmetry and the CP violating asymmetry in the forward-backward asymmetry for the radiative dileptonic B-meson decays $B_{d}\to γ\ell^+ \ell^-$ for the $\ell= e, μ, τ$ channels. It is observed that these asymmetries are quite sizable and $B_{d}\to γ\ell^+ \ell^-$ decays seem promising for inves

E. Tsitsishvili, R. v. Baltz, H. Kalt

The decay time of the linear polarization degree of the luminescence in strongly confined semiconductor quantum dots with asymmetrical shape is calculated in the frame of second-order quasielastic interaction between quantum dot charge carriers and LO phonons. The phonon bottleneck does not prevent significantly the relaxation processes and the calculated de