August 2000 arXiv papers — page 6

Takeo Inami, Yorinori Saito, Masayoshi Yamamoto

We construct the {\cal N}=4 supersymmetric nonlinear sigma model in three dimensions which can be expanded in 1/N. We evaluate the effective action at leading order in the 1/N expansion and show the finiteness of the model to this order.

E. Z. Kuchinskii, M. V. Sadovskii

We analyze the anomalies of superconducting state (s and d-wave pairing) in a simple model of pseudogap state, induced by fluctuations of short - range order (e.g. antiferromagnetic), based on the model Fermi surface with "hot patches". We derive a system of recursion relations for Gorkov's equations which take into account all diagrams of pertur

Ruediger Schack, Todd A. Brun, Carlton M. Caves

We state a quantum version of Bayes's rule for statistical inference and give a simple general derivation within the framework of generalized measurements. The rule can be applied to measurements on N copies of a system if the initial state of the N copies is exchangeable. As an illustration, we apply the rule to N qubits. Finally, we show that quantum s

Royal Skousen

This paper serves as a bridge between quantum computing and analogical modeling (a general theory for predicting categories of behavior in varying contexts). Since its formulation in the early 1980s, analogical modeling has been successfully applied to a variety of problems in language. Several striking similarities between quantum mechanics and analogical m

W. Hänsel, J. Reichel, P. Hommelhoff, T. W. Hänsch

We demonstrate an integrated magnetic ``atom chip'' which transports cold trapped atoms near a surface with very high positioning accuracy. Time-dependent currents in a lithographic conductor pattern create a moving chain of magnetic potential wells; atoms are transported in these wells while remaining confined in all three dimensions. We achieve flu

J. F. Du, M. J. Shi, J. H. Wu, X. Y. Zhou

In this paper, we present the experimental realization of multi-qubit gates $% Λ_n(not) $ in macroscopic ensemble of three-qubit and four-qubit molecules. Instead of depending heavily on the two-bit universal gate, which served as the basic quantum operation in quantum computing, we use pulses of well-defined frequency and length that simultaneously apply to

Hagen Kleinert

Starting from a forward--backward path integral of a point particle in a bath of harmonic oscillators, we derive the Fokker-Planck and Langevin equations with and without inertia. Special emphasis is placed upon the correct operator order in the time evolution operator. The crucial step is the evaluation of a Jacobian with a retarded time derivative by analy

G. S. Agarwal, J. Banerji

We show that in parametrically driven systems and, more generally, in systems in coherent states, off-resonant pumping can cause a transition from a continuum energy spectrum of the system to a discrete one, and result in quantum revivals of the initial state. The mechanism responsible for quantum revivals in the present case is different from that in the no

Howard A. Smith

Space Science enjoys broad public support in the US. People say they follow developments with interest, and that the programs are worth their cost. This attitude seems to arise in part because of the intrinsic accessibility and appeal of the subject matter. Yet at the same time the public is often disturbingly ignorant about basic facts. In this article I su

A. L. Sorokin

We propose new construction of dependent variables for equations of an ideal barotropic fluid. This construction is based on a direct generalization of the known connection between Schroedinger equation and a system of Euler-type equations. The system for two complex-valued functions is derived that is equivalent to Euler equations. Possible advantages of th

K. Bennaceur, J. Dobaczewski, M. Ploszajczak

We discuss pairing correlations in weakly bound neutron rich nuclei, by using the coordinate-space Hartree-Fock-Bogolyubov approach which allows to take properly into account the coupling to particle continuum. We show that the additional pairing binding energy acts against a development of an infinite rms radius, even in situations when an l=0 single-partic

Ziwei Lin, C. M. Ko

An effective hadronic Lagrangian including the charm mesons is introduced to study their interactions in hadronic matter. Using coupling constants that are determined either empirically or by the SU(4) symmetry, we have evaluated the absorption cross sections of $J/ψ$ and the scattering cross sections of $D$ and $D^*$ by $π$ and $ρ$ mesons.

J. M. Tuwankotta, G. R. W. Quispel

In this paper we study the performance of a symplectic numerical integrator based on the splitting method. This method is applied to a subtle problem i.e. higher order resonance of the elastic pendulum. In order to numerically study the phase space of the elastic pendulum at higher order resonance, a numerical integrator which preserves qualitative features

Kenneth S. Alexander, Nobuo Yoshida

We establish upper bounds for the spectral gap of the stochastic Ising model at low temperatures in an n-by-n box with boundary conditions which are not purely plus or minus; specifically, we assume the magnitude of the sum of the boundary spins over each interval of length n in the boundary is bounded by δn, where δ< 1. We show that for any such boundary co

A. M. Garsia, Mike Zabrocki

Let $K(q,t)= \|K_{\laμ}(q,t)\|_{\la,μ}$ be the Macdonald q,t-Kostka matrix and $K(t)=K(0,t)$ be the matrix of the Kostka-Foulkes polynomials K_{\laμ}(t). In this paper we present a new proof of the polynomiality of the q,t-Kostka coefficients that is both short and elementary. More precisely, we derive that $K(q,t)$ has entries in \ZZ[q,t] directly from the

Thomas A. Nevins

Fix a ruled surface S obtained as the projective completion of a line bundle L on a complex elliptic curve; we study the moduli problem of parametrizing certain pairs consisting of a sheaf E on S and a map of E to a fixed reference sheaf on S. We prove that the full moduli stack for this problem is representable by a scheme in some cases. Moreover, the modul

Abdellatif Bourhim

We study in this paper the concept of bounded point evaluations for cyclic operators. We give a negative answer to a question of L.R. Williams {\it Dynamic Systems and Apllications} 3(1994) 103-112. Furthermore, we generalize some results of Williams and give a simple proof of theorem 2.5 of L.R. Williams (The Local Spectra of Pure Quasinormal Operators J. M

H. Ahmedov, I. H. Duru

Using the representation of E_q(2) on the non-commutative space zz^*-qz^*z=σ; q<1, σ>0 summation formulas for the product of two, three and four q-Kummer functions are derived.

I. Heckenberger, A. Schueler

Let G=G(t,z) be one of the N^2-dimensional bicovariant first order differential calculi for the quantum groups GL_q(N), SL_q(N), O_q(N), or Sp_q(N), where q is a transcendental complex number and z is a regular parameter. It is shown that the de Rham cohomology of Woronowicz&#39; external algebra G^ coincides with the de Rham cohomologies of its left-coinvar

Doug Pickrell, Eugene Z. Xia

The mapping class group of a compact oriented surface of genus greater than one with boundary acts ergodically on connected components of the representation variety corresponding to a connected compact Lie group, for every choice of conjugacy class boundary condition.

Alexander Isaev

We show that if the group of holomorphic automorphisms of a connected Stein manifold $M$ is isomorphic to that of ${\bf C}^n$ as a topological group equipped with the compact-open topology, then $M$ is biholomorphically equivalent to ${\bf C}^n$.

P. E. T. Jorgensen, A. Paolucci

We identify multiresolution subspaces giving rise via Hankel transforms to Bessel functions. They emerge as orthogonal systems derived from geometric Hilbert-space considerations, the same way the wavelet functions from a multiresolution scaling wavelet construction arise from a scale of Hilbert spaces. We study the theory of representations of the C*-algebr

A. C. Petkou, G. Siopsis

We discuss the relevance of the Lee-Yang edge singularity to the finite-temperature Z_2-symmetry restoration transition of the Gross-Neveu model in three dimensions. We present an explicit result for its large-N free energy density in terms of Zeta(3) and the absolute maximum of Clausen&#39;s function.

K. Uzawa, J. Soda

Recently, the self-tuning mechanism of cancellation of vacuum energy has been proposed in which our universe is a flat 3-brane in a 5-dimensional spacetime. In this letter, the self-tuning mechanism of dark energy is proposed by considering the cosmological matter in the brane world. In our model, the bulk scalar field takes the role of the dark energy and i

A. Iorio, L. O&#39;Raifeartaigh, S. Wolf

The purpose of this paper is twofold. The first purpose is to review a systematic construction of Noether currents for supersymmetric theories, especially effective supersymmetric theories. The second purpose is to use these currents to derive the mass-formula for the quantized Seiberg-Witten model from the supersymmetric algebra. We check that the mass-form

D. A. Ross, L. J. Weston

We evolve virtual photon parton densities up to the SUSY threshold and higher using coupled inhomogeneous DGLAP differential equations. Reliable input parameterizations were available from the c-quark threshold. Limited $P^2$ ( target photon virtuality ) dependence is observed. The difference to the photon structure function is shown to be significant with t

Andrzej J. Buras, Robert Buras

We point out that there exists an absolute lower bound on sin 2βin all models with minimal flavour violation (MFV), that do not have any new operators beyond those present in the Standard Model and in which all flavour changing transitions are governed by the CKM matrix with no new phases beyond the KM phase. This bound depends only on V_{cb}, V_{ub} and the

Th. Feldmann

Recently it has been shown that in the large-recoil limit new symmetries emerge which impose various relations on form factors that parametrise the decay of heavy B mesons into light mesons. These symmetry relations are broken by radiative QCD corrections. We show that these corrections are perturbatively calculable, and present results to first order in the

W. Bernreuther, A. Brandenburg, Z. G. Si

Future hadron collider experiments will allow for a detailed investigation of $t\bar{t}$ spin correlation effects. In this talk, recent progress in the theoretical description of these effects is reported. In particular, next-to-leading order results for the $t\bar t$ spin correlations in $q\bar{q}\to t\bar{t}X$ are presented, using various spin quantization

M. F. McDermott

A personal summary of the discussions which took place at the informal meeting in Amirim, Israel from June 1-4 2000, concerning the dipole picture of small-$x$ physics is presented. The broad aim of the meeting was to address the question ``Has HERA reached a new QCD regime (at small $x$) ?&#39;&#39;. The new regime in question is the high-density, but weak-

Stefan Groote, Oleg Yakovlev

Starting from general considerations about the different concepts which exist for the definition of the quark mass near the pair production threshold, we introduce the definition of a mass with a dynamic degree of freedom that extends the previously given concept of the static PS mass.

M. Engelhardt, M. Faber, H. Reinhardt

A model for the infrared sector of SU(2) Yang-Mills theory, based on magnetic vortices represented by (closed) random surfaces, is presented. The model quantitatively describes both confinement and the topological aspects of Yang-Mills theory. Details (including an adequate list of references) can be found in hep-lat/9912003 and hep-lat/0004013, both to appe

L. Mikaelyan

This is a report on recent progress and developments since the NANP&#39;99 Conference in current and future long baseline (~1 km) and very long baseline (~100 - 800 km) oscillation experiments at reactors. These experiments, under certain assumptions, can fully reconstruct the internal mass structure of the electron neutrino and provide laboratory test of so

A. O. Barvinsky, D. V. Nesterov

We develop a general framework for effective equations of expectation values in quantum cosmology and pose for them the quantum Cauchy problem with no-boundary and tunneling wavefunctions. Cosmological configuration space is decomposed into two sectors that give qualitatively different contributions to the radiation currents in effective equations. The field

Mark Johnson, Stefan Riezler

This paper describes a method for estimating conditional probability distributions over the parses of ``unification-based&#39;&#39; grammars which can utilize auxiliary distributions that are estimated by other means. We show how this can be used to incorporate information about lexical selectional preferences gathered from other sources into Stochastic ``Un

Mark Johnson, Stuart Geman, Stephen Canon, Zhiyi Chi

Log-linear models provide a statistically sound framework for Stochastic ``Unification-Based&#39;&#39; Grammars (SUBGs) and stochastic versions of other kinds of grammars. We describe two computationally-tractable ways of estimating the parameters of such grammars from a training corpus of syntactic analyses, and apply these to estimate a stochastic version

G. P. Kubalski, M. Napiorkowski

The shape of a liquid drop placed in a cone is analyzed macroscopically. Depending on the values of the cone opening angle, the Young angle and the line tension four different interfacial configurations may be realized. The phase diagram in these variables is constructed and discussed; it contains both the first- and the second-order transition lines. In par

M. Hart, P. Jefferies, P. M. Hui, N. F. Johnson

We present a dynamical theory of a multi-agent market game, the so-called Minority Game (MG), based on crowds and anticrowds. The time-averaged version of the dynamical equations provides a quantitatively accurate, yet intuitively simple, explanation for the variation of the standard deviation (`volatility&#39;) in MG-like games. We demonstrate this for the

Sandro Scandolo, Jorge Kohanoff

An efficient method for calculating the electronic structure of systems that need a very fine sampling of the Brillouin zone is presented. The method is based on the variational optimization of a &#34;single&#34; (i.e. common to all points in the Brillouin zone) basis set for the expansion of the electronic orbitals. Considerations from k.p-approximation the

V. Janis, D. Vollhardt

The electrical {\em dc}-conductivity of disordered, non-interacting electrons is calculated in the asymptotic limit of high lattice dimensions $d\to \infty$. To go beyond the lowest-order contribution in the expansion parameter $1/d$ of the single bubble diagram, vertex corrections are calculated from an asymptotic expression for the two-particle vertex. A m

Aleksey D. Drozdov

Constitutive equations are derived for the viscoelastoplastic response of amorphous glassy polymers at isothermal loading with small strains. A polymer is treated as an ensemble of cooperatively relaxing regions (CRR) which rearrange at random times as they are thermally agitated. Rearrangement of CRRs reflects the viscoelastic response of the bulk medium. A

L. Didukh, V. Hankevych, Yu. Skorenkyy

In the present paper we study some correlation effects in a generalized Hubbard model with correlated hopping within low-temperature region using a generalized mean-field approximation. It is shown that in a series of cases the model leads to consequences deviating essentially from those of the Hubbard model. We consider the possibility of applying the resul

A. S. Alexandrov, A. M. Bratkovsky

The semi-classical Lifshitz-Kosevich (LK) description of quantum oscillations is extended to a multiband two-dimensional Fermi liquid with a constant number of electrons. The amplitudes of novel oscillations with combination frequencies, recently predicted and observed experimentally, are analytically derived and compared with the single-band amplitudes. The

H. Mathur, Harold U. Baranger

The effect of silicon-oxide interface roughness on the weak-localization magnetoconductance of a silicon MOSFET in a magnetic field, tilted with respect to the interface, is studied. It is shown that an electron picks up a random Berry&#39;s phase as it traverses a closed orbit. Effectively, due to roughness, the electron sees an uniform field parallel to th

C. D. Batista, G. Ortiz

We introduce a new spin-fermion mapping, for arbitrary spin $S$ generating the SU(2) group algebra, that constitutes a natural generalization of the Jordan-Wigner transformation for $S=1/2$. The mapping, valid for regular lattices in any spatial dimension $d$, serves to unravel hidden symmetries in one representation that are manifest in the other. We illust

S. Lubeck, D. Dhar

We consider the directed Abelian sandpile model in the presence of sink sites whose density f_t at depth t below the top surface varies as c~1/t^chi. For chi>1 the disorder is irrelevant. For chi<1, it is relevant and the model is no longer critical for any nonzero c. For chi=1 the exponents of the avalanche distributions depend continuously on the amplitude

J. E. Larkin, T. M. Glassman, P. Wizinowich, D. S. Acton

We report on the first observation of cosmologically distant field galaxies with an high order Adaptive Optics (AO) system on an 8-10 meter class telescope. Two galaxies were observed at 1.6 microns at an angular resolution as high as 50 milliarcsec using the AO system on the Keck-II telescope. Radial profiles of both objects are consistent with those of loc

D. W. Fox, W. H. G. Lewin, A. Fabian, K. Iwasawa

We report on multi-epoch X-ray observations of the Type IIn (narrow emission line) supernova SN 1995N with the ROSAT and ASCA satellites. The January 1998 ASCA X-ray spectrum is well fitted by a thermal bremsstrahlung (kT~10 keV, N_H~6e20 cm^-2) or power-law (alpha~1.7, N_H~1e21 cm^-2) model. The X-ray light curve shows evidence for significant flux evolutio

J. Poirier

The theoretical calculations of the production of neutrinos via cosmic rays incident upon the earth&#39;s atmosphere (Barr et al., 1989; Becker-Szendy et al., 1992; Bugaev & Naumov, 1989; Gaisser et al, 1988; Honda et al., 1995) are examined. These calculations use a one-dimensional approximation in the production, transport, and decay of the produced partic

J. Poirier

The theoretical Monte Carlo calculations of the production of neutrinos via cosmic rays incident upon the earth&#39;s atmosphere are examined. The calculations are sensitive to the assumed ratio of pi+ / pi- production cross sections; this ratio appears to be underestimated in the theory relative to the experimentally measured ratio. Since the neutrino detec

T. J. Davidge

Images recorded through J, H, K, 2.2 micron continuum and CO filters have been obtained of a sample of metal-poor ([Fe/H] < -1.3) globular clusters in the inner spheroid of the Galaxy. The shape and color of the upper giant branch on the (K, J-K) CMD, combined with the K brightness of the RGB-tip, are used to estimate the metallicity, reddening, and distance

A. Roesch, J. Carpenter, S. Desch, J. Gress

An increased data sample of identified secondary muons is collected at detection level. Project GRAND identifies secondary cosmic ray muons from electrons utilizing a thin steel absorber and tracking (PWC) chambers. The resulting angular resolution for the primary is about +/- 5 degrees. Since there is a 1.5% probability that a 100 GeV gamma primary will pro

Toshihiro Kawaguchi, Toshiya Shimura, Shin Mineshige

We construct a disk-corona model which accounts for the optical-to-X-ray spectral properties of Seyfert nuclei and QSOs. We study emission spectrum emerging from a vertical disk-corona structure composed of two-temperature plasma by solving hydrostatic equilibrium and radiative transfer self-consistently. A fraction $f$ of viscous heating is assumed to be di

Daniela Calzetti

I review the effects of dust, both in absorption and in emission, on the spectral energy distributions (SEDs) of Local star-forming galaxies. The energy balance between the stellar light absorbed by dust at UV-optical-nearIR wavelengths and the energy re-emitted by dust in the far infrared (FIR) shows that the amount of dust extinction affecting the galaxy c

Francesca Primas, Paolo Molaro, Piercarlo Bonifacio, Vanessa Hill

We report on a attempt to detect beryllium in two dwarf stars of the Galactic halo with metallicities below one thousandth solar. The data were obtained during the Commissioning of the Ultraviolet and Visible Echelle Spectrograph (UVES) mounted on the ESO VLT Kueyen telescope, and show the potential of UVES for studies in the UV-optical domain. We claim a be

Donald P. Schneider, Xiaohui Fan, Michael A. Strauss, James E. Gunn

We report the discovery of a pair of z = 4.25 quasars with a separation of 33 arcseconds. The brighter of the two objects was identified as a high-redshift quasar candidate from Sloan Digital Sky Survey multicolor imaging data, and the redshift was measured from a spectrum obtained with the Hobby-Eberly Telescope. The slit orientation of this observation {\i

G. A. Richter, J. Greiner

We report the discovery of a new variable star, called S 10947 Aql, as the likely optical counterpart of RX J2009.8+1557. The optical variability pattern as well as the detected X-ray emission suggest that it is a chromospherically active binary of the RS Canum Venaticorum type. We discovered an occasional disappearance of the eclipsing minima as well as lar

W. Stolzmann, T. Bloecker

Starting from the Helmholtz free energy we calculate analytically first- and second-order derivatives, as internal energy and specific heats, for the ideal system and the exchange and correlation interactions covering a broad range of degeneracy and relativity. The complex physics of Coulomb interactions is expressed by Pade Approximants, which reflect the a

S. Mengel, F. Eisenhauer, M. Tecza, N. Thatte

SINFONI, the SINgle Faint Object Near-infrared Investigation, is an instrument for the Very Large Telescope (VLT), which will start its operation mid 2002 and allow for the first time near infrared (NIR) integral field spectroscopy at the diffraction limit of an 8-m telescope. SINFONI is the combination of two state-of-the art instruments, the integral field

Eric G. Blackman

Magnetic fields likely play a fundamental intermediary role between gravity and radiation in many astrophysical rotators. They can, among other things, 1) induce and be amplified by turbulence, 2) energize coronae, 3) launch and collimate outflows in ``spring&#39;&#39; or ``fling&#39;&#39; mechanisms. The first is widely recognized to be important for angula

M. S. Brotherton, Hien D. Tran, R. H. Becker, Michael D. Gregg

We present a very high signal-to-noise ratio composite spectrum created using 657 radio-selected quasars from the FIRST Bright Quasar Survey. The spectrum spans rest-frame wavelengths 900 - 7500 Angstroms. Additionally we present composite spectra formed from subsets of the total data set in order to investigate the spectral dependence on radio loudness and

D. A. Gadotti, S. dos Anjos

We have done a robust statistical analysis of UBV color profiles of 257 Sbc barred and unbarred galaxies. We found that there is an excess of barred galaxies among the objects with null or positive (bluish inward) color gradients, which seems to indicate that bars act as a mechanism of homogenization of the stellar population along galaxies. Moreover, the re

Paul Fendley

A fundamental result relevant to spin chains and two-dimensional disordered systems is that the sphere sigma model with instanton coupling theta=pi has a non-trivial low-energy fixed point and a gapless spectrum. This result is extended to two series of sigma models with theta=pi: the SU(N)/SO(N) sigma models flow to the SU(N)_1 WZW theory, while the O(2N)/O

M. J. Fromerth, F. Melia, D. Leahy

Strong fluorescent Fe line emission at 6.4 keV has been observed from the Sgr B2 giant molecular cloud located in the Galactic Center region. The large equivalent width of this line and the lack of an apparent illuminating nearby object indicate that a time-dependent source, currently in a low-activity state, is causing the fluorescent emission. It has been

M. B. Hecht, C. D. Roberts, S. M. Schmidt

We calculate the pion&#39;s valence-quark momentum-fraction probability distribution using a Dyson-Schwinger equation model. Valence-quarks with an active mass of 0.30 GeV carry 71% of the pion&#39;s momentum at a resolving scale q_0=0.54 GeV = 1/(0.37 fm). The shape of the calculated distribution is characteristic of a strongly bound system and, evolved fro

C. Panagiotakopoulos, A. Pilaftsis

We consider the simplest and most economic version among the proposed non-minimal supersymmetric models, in which the $μ$-parameter is promoted to a singlet superfield, whose all self-couplings are absent from the renormalizable superpotential. Such a particularly simple form of the renormalizable superpotential may be enforced by discrete $R$-symmetries whi

J. D. Cohn, C. S. Kochanek, B. A. McLeod, C. R. Keeton

We consider a wide range of parametric mass models for B 1933+503, a ten-image radio lens, and identify shared properties of the models with the best fits. The approximate rotation curves varies by less than 8.5% from the average value between the innermost and the outermost image (1.5h^{-1} kpc to 4.1h^{-1} kpc) for models within 1 \sigma of the best fit, a

Paulo F. Farinas

It is shown that the recently observed and unexplained behavior for the spin diffusion in 3He films can be understood in terms of the Fermi liquid theory, provided nonperturbative effects characteristic of the two dimensions are taken into account. It is conjectured that such a behavior suggests the onset of a regime in which spin-current is conserved.

Anand T. N. Kumar, Florin Rosca, Allan Widom, Paul M. Champion

We present an effective linear response approach to pump-probe femtosecond coherence spectroscopy in the well separated pulse limit. The treatment presented here is based on a displaced and squeezed state representation for the non-stationary states induced by an ultrashort pump laser pulse or a chemical reaction. The subsequent response of the system to a d

A. Mennim, R. A. Battye

In this paper we study brane-world scenarios with a bulk scalar field, using a covariant formalism to obtain a 4D Einstein equation via projection onto the brane. We discuss, in detail, the effects of the bulk on the brane and how the scalar field contribute to the gravitational effects. We also discuss choice of conformal frame and show that the frame selec

K. Zarembo

The lepton asymmetry of order one is not excluded experimentally and, if present, can lead to interesting phenomena in the early Universe. It is shown that, when the temperature is above the quark-hadron transition, the lepton asymmetry induces chemical potentials for electric charge and for baryon number, and makes the quark-gluon plasma electrically charge

Viqar Husain, Michel Olivier

We describe results of a numerical calculation of circularly symmetric scalar field collapse in three spacetime dimensions with negative cosmological constant. The procedure uses a double null formulation of the Einstein-scalar equations. We see evidence of black hole formation on first implosion of a scalar pulse if the initial pulse amplitude $A$ is greate

Kei-ichi Maeda, David Wands

We derive the four-dimensional field equations for the induced metric and scalar field on the world-volume of a 3-brane in a five-dimensional bulk with Einstein gravity plus a self-interacting scalar field. We calculate the effective four-dimensional gravitational constant and cosmological constant for arbitrary forms of the brane tension and self-interactio

Boris Shapiro

A simple model for addition spectra in quantum dots is proposed and studied. It is an extension of the standard charging model which assumes that the charge spreads uniformely over the entire dot. The proposed model attempts to account for a nonuniform distribution of the charge, by introducing an extra parameter U. When U increases, the distribution of the

Ishwaree P. Neupane

We consider the theory of higher derivative gravity with non-factorizable Randall-Sundrum type space-time and obtain the metric solutions which characterize the $p$-brane world-volume as a curved or planar defect embedded in the higher dimensions. We consider the string inspired effective actions of the dilatonic Gauss-Bonnet type in the brane background and

G. V. Astakhov, V. A. Kosobukin, V. P. Kochereshko, D. R. Yakovlev

An approach is proposed to determine parameters of homogeneous and inhomogeneous broadening for reflection lines of quasi-two-dimensional excitons in semiconductor quantum well structures. A phenomenological model is developed taking into account fluctuations of the exciton energy which are expected to cause inhomogeneous broadening of exciton reflectivity l

James F. Lutsko

It is shown that the equilibrium Generalized Mean Spherical Model of fluid structure may be extended to nonequilibrium states with equation of state information used in equilibrium replaced by an exact condition on the two-body distribution function. The model is applied to the homogeneous cooling state of granular fluids and upon comparison to molecular dyn

James F. Lutsko

A model for the pair distribution function of nonequilibrium hard-core fluids is proposed based on a model for the effect of velocity correlations on the structure. Good agreement is found with molecular dynamics simulations of granular fluids and of sheared elastic hard spheres. It is argued that the incorporation of velocity correlations are crucial to cor

H. Czyz, J. H. Kuehn

A Monte Carlo generator has been constructed to simulate the reaction e^+e^- \to γ+ 4 π, where the photon is assumed to be observed in the detector. Only initial state radiation is considered. Additional collinear photon radiation has been incorporated with the technique of structure functions. Predictions are presented for cms energies of 1GeV, 3GeV and 10G

R. P. Croce, Th. Demma, V. Pierro, I. M. Pinto

The final inspiral phase in the evolution of a compact binary consisting of black holes and/or neutron stars is among the most probable events that a network of ground-based interferometric gravitational wave detectors is likely to observe. Gravitational radiation emitted during this phase will have to be dug out of noise by matched-filtering (correlating) t

W. Slominski, J. Szwed

Advantages of introducing the electron structure function (ESF) in electron induced processes are demonstrated. Contrary to the photon structure function it is directly measured in such processes. At present energies a simultaneous analysis of both the electron and the photon structure functions gives an important test of the experimentally applied methods.

P. Di Bari, R. Foot

We show how active-sterile neutrino oscillations in the early Universe can play an interesting role in explaining the current observations of CMBR anisotropies and light element abundances. We describe different possible phenomenological scenarios in the interpretation of present data and how active-sterile neutrino oscillations can provide a viable theoreti

X. Calmet

Inspired by the concept of complementarity, we present a illustrative model for the weak interactions with unbroken gauge symmetry and unbroken supersymmetry. The observable particles are bound states of some more fundamental particles. Supersymmetry is broken at the macroscopic scale of the observable particles by a discrete symmetry but remains exact at th

M. Beneke, Th. Feldmann

Recently it has been shown that symmetries emerging in the heavy quark and large recoil energy limit impose various relations on form factors that parametrise the decay of B mesons into light mesons. These symmetries are broken by perturbative effects. In this paper we discuss the structure of heavy-to-light form factors including such effects and compute sy

Xavier Calmet, Harald Fritzsch

We discuss an alternative version of the electroweak standard model, in which only the heavy t quark, not the light fermions, couples to the Higgs boson with a strength given by the standard model. The Higgs particle decays dominantly into two gluons jets. The branching ratio for the 2 gamma decay is about 3.5%. The Higgs particle would be a narrow object (w

Julio Gea-Banacloche

The evolution of a two-state system driven by a sequence of imperfect pi pulses (with random phase or amplitude errors) is calculated. The resulting decreased fidelity is used to derive a plausible limit on the performance of &#34;bang-bang&#34; control methods for the suppression of decoherence.

Farhan Saif

We investigate quantum revivals in the dynamics of an atom in an atomic Fermi accelerator. It is demonstrated that the external driving field influences the revival time significantly. Analytical expressions are presented which are based on semiclassical secular theory. These analytical results explain the dependence of the revival time on the characteristic

Farhan Saif

We study the dynamical localization of cold atoms in Fermi accelerator both in position space and in momentum space. We report the role of classical phase space in the development of dynamical localization phenomenon. We provide set of experimentally assessable parameters to perform this work in laboratory.

G. L. Klimchitskaya, S. I. Zanette, A. O. Caride

We find the lateral projection of the Casimir force for a configuration of a sphere above a corrugated plate. This force tends to change the sphere position in the direction of a nearest corrugation maximum. The probability distribution describing different positions of a sphere above a corrugated plate is suggested which is fitted well with experimental dat

Seth Lloyd, Lorenza Viola

We investigate the control resources needed to effect arbitrary quantum dynamics. We show that the ability to perform measurements on a quantum system, combined with the ability to feed back the measurement results via coherent control, allows one to control the system to follow any desired open-system evolution. Such universal control can be achieved, in pr

S. Baskal, Y. S. Kim

The ABCD matrix is one of the essential mathematical instruments in optics. It is the two-by-two representation of the group Sp(2), which is applicable to many branches of physics, including squeezed states of light, special relativity and coupled oscillators. It is pointed out that the shear representation is oriented to binary logic which may be friendly t

Shinya Watanabe, Vachtang Putkaradze, Tomas Bohr

We study laminar thin film flows with large distortions in the free surface using the method of averaging across the flow. Two concrete problems are studied: the circular hydraulic jump and the flow down an inclined plane. For the circular hydraulic jump our method is able to handle an internal eddy and separated flow. Assuming a variable radial velocity pro

P. Maris

The ladder-rainbow truncation of the set of Dyson-Schwinger equations is used to study the pion and kaon electromagnetic form factors and the $γ^\star π^0 γ$ transition form factor in impulse approximation. With model parameters previously fixed by the pseudoscalar meson masses and decay constants, the obtained form factors are in good agreement with the dat

Peter Jacobs, Glenn Cooper

The spatial distribution of interactions in high energy collisions of heavy nuclei is discussed using the wounded nucleon, binary collision, hard sphere, and colliding disk parameterizations of interaction densities. The mean radius, its dispersion, and the eccentricity of the interaction region are calculated as a function of impact parameter. The eccentric

Fridolin Okkels

The intermittent dynamics of the turbulent GOY shell-model is characterised by a single type of burst-like structure, which moves through the shells like a front. This temporal structure is described by the dynamics of the instantaneous configuration of the shell-amplitudes revealing a approximative chaotic attractor of the dynamics.

Steven Tomsovic

Over the preceeding twenty years, the role of underlying classical dynamics in quantum mechanical tunneling has received considerable attention. A number of new tunneling phenomena have been uncovered that have been directly linked to the set of dynamical possibilities arising in simple systems that contain at least some chaotic motion. These tunneling pheno

Ph. Feinsilver, J. Kocik, R. Schott

We investigate the structure of the Schrodinger algebra and its representations in a Fock space realized in terms of canonical Appell systems. Generalized coherent states are used in the construction of a Hilbert space of functions on which certain commuting elements act as self-adjoint operators. This yields a probabilistic interpretation of these operators

Alexander Schmidt

We remove the assumption &#34;let p be odd or k totally imaginary&#34; from several well-known theorems in Galois cohomology of number fields. For example, we show that the Galois group of the maximal extension of a number field k which is unramified outside 2 has a finite cohomological 2-dimension (also if k has real places). (The dvi-file requires the xypi

Jennifer M. Johnson, János Kollár

We determine the complete list of anticanonically embedded quasi smooth log Fano 3-folds in weighted projective 4-spaces. This implies that the Reid-Fletcher list of 95 types of anticanonically embedded quasi smooth terminal Fano threefolds in weighted projective 4-spaces is complete. We also prove that there are only finitely many families of quasi smooth C

I. Petras, L. Dorcak, P. O&#39;Leary, B. M. Vinagre

This paper deals with fractional-order controlled systems and fractional-order controllers in the frequency domain. The mathematical description by fractional transfer functions and properties of these systems are presented. The new ways for modelling of fractional-order systems are illustrated with a numerical example and obtained results are discussed in c