August 2003 arXiv papers — page 19

Cristian F. Moukarzel, Hector Pacheco-Martinez, J. C. Ruiz-Suarez, Ana M. Vidales

We present experimental and numerical results for displacement response functions in packings of rigid frictional disks under gravity. The central disk on the bottom layer is shifted upwards by a small amount, and the motions of disks above it define the displacement response. Disk motions are measured with the help of a still digital camera. The responses s

Zhongsheng Zhang, David A. Rabson

To test the quality of a tunnel junction, one sometimes fits the bias-dependent differential conductance to a theoretical model, such as Simmons's formula. Recent experimental work by Åkerman and collaborators, however, has demonstrated that a good fit does not necessarily imply a good junction. Modeling the electrical and thermal properties of a tunnel

Mucio A. Continentino

Near quantum Lifshitz points the stiffness of the lifetime of the spin fluctuations is very small. This gives rise to a regime where the critical fluctuations are local in space but extended along the time directions. The Fermi liquid properties in this local quantum regime is governed by a single energy scale, the coherence temperature. These results are re

P. Plochocka, P. Kossacki, W. Maslana, J. Cibert

We present an absorption study of the neutral and positively charged exciton (trion) under the influence of a femtosecond, circularly polarized, resonant pump pulse. Three populations are involved: free holes, excitons, and trions, all exhibiting transient spin polarization. In particular, a polarization of the hole gas is created by the formation of trions.

M. Matsuura, Pengcheng Dai, H. J. Kang, J. W. Lynn

We have measured the effect of a c-axis aligned magnetic field on the long-range magnetic order of insulating Nd2CuO4, as-grown nonsuperconducting and superconducting Nd1.85Ce0.15CuO4. On cooling from room temperature, Nd2CuO4 goes through a series of antiferromagnetic (AF) phase transitions with different noncollinear spin structures. In all phases of Nd2Cu

K. Ziegler

The Bose-Hubbard model of a two-fold degenerate Bose gas is studied in an optical lattice with one particle per site and virtual tunneling to empty and doubly-occupied sites. An effective Hamiltonian for this system is derived within a continued-fraction approach. The ground state of the effective model is studied in mean-field approximation for a modulated

A. M. Yakunin, A. Yu. Silov, P. M. Koenraad, W. Van Roy

We present results on the direct spatial mapping of the wave-function of a hole bound to a Mn acceptor in GaAs. To investigate individual Mn dopants at the atomic scale in both ionized and neutral configurations, we used a room temperature cross-sectional scanning tunneling microscope (X-STM). We found that in the neutral configuration manganese manifests it

Rajeev Ahluwalia, Turab Lookman, Avadh Saxena, Wenwu Cao

We study theoretically the influence of the underlying domain microstructure on the electromechanical properties of ferroelectrics. Our calculations are based on a continuum approach that incorporates the long-range elastic and electrostatic interactions. The theory is used to simulate the piezoelectric properties of a two dimensional model ferroelectric cry

K. V. Samokhin, B. Mitrovic

We show that the nodal quasiparticles have significant effect on the classical phase fluctuations in a quasi-two-dimensional d-wave superconductor. They give rise to singularities in the temperature behavior of some of the coupling constants in the phase-only effective action. One of the consequences is that the classical XY-model is not adequate for the des

A. Kesting, C. Timm

The spin configuration induced by single holes and hole pairs doped into stoichiometric, antiferromagnetic cuprates is considered. Unrestricted Hartree-Fock calculations for the three-band Hubbard model are employed to study spin-polaron and vortex-like (meron) solutions. Meron solutions for a single hole are found to be metastable with higher energy than sp

J. Vanacken, L. Weckhuysen, T. Wambecq, P. Wagner

A large positive magnetoresistivity (up to tens of percents) is observed in both underdoped and overdoped superconducting La2-xSrxCuO4 epitaxial thin films at temperatures far above the superconducting critical temperature Tc. For the underdoped samples, this magnetoresistance far above Tc cannot be described by the Kohler rule and we believe it is to be att

Dario Alfè

First principles calculations based on density functional theory, with generalised gradient corrections and ultrasoft pseudopotentials, have been used to simulate solid and liquid aluminium in direct coexistence at zero pressure. Simulations have been carried out on systems containing up to 1000 atoms for 15 ps. The points on the melting curve extracted from

A. A. Tsvetkov, F. P. Mena, P. H. M. van Loosdrecht, D. van der Marel

Optical and magneto-optical properties of YVO$_3$ single crystal were studied in FIR, visible, and UV regions. Two structural phase transitions at 75 K and 200 K were observed and established to be of the first and second order, respectively. The lattice has an orthorhombic $Pbnm$ symmetry both above 200 K as well as below 75 K, and is found to be dimerized

M. Sigrist, A. Fuhrer, T. Ihn, K. Ensslin

The Aharonov-Bohm effect is measured in a four-terminal open ring geometry based on a Ga[Al]As heterostructure. Two quantum dots are embedded in the structure, one in each of the two interfering paths. The number of electrons in the two dots can be controlled independently. The transmission phase is measured as electrons are added to or taken away from the i

Moshe Goldstein, Richard Berkovits

In this paper we study the orbital weak-field susceptibility of two-dimensional diffusive mesoscopic systems. For the previously unstudied regime of temperatures lower than the mean level spacing we find unexpected strong temperature as well as statistical ensemble dependence of the average and typical susceptibilities. An explanation for these features is g

Francesco Rao, Andrea Crisanti, Felix Ritort

The time-dependent susceptibility for the finite-size mean-field Random Orthogonal model (ROM) is studied numerically for temperatures above the mode-coupling temperature. The results show that the imaginary part of the susceptibility $χ''(ν)$ obeys the scaling form proposed for glass-forming liquids with the peak frequency decreasesing as the temper

Z. G. Yu, W. H. Lau, M. E. Flatte'

We calculate circularly polarized luminescence emitted parallel (vertical emission) and perpendicular (edge emission) to the growth direction from a quantum well in a spin light-emitting diode (spin-LED) when either the holes or electrons are spin polarized. It is essential to account for the orbital coherence of the spin-polarized holes when they are captur

M. Sigrist, A. Fuhrer, T. Ihn, K. Ensslin

We use the Aharonov-Bohm effect in a four-terminal ring based on a Ga[Al]As heterostructure for the measurement of the relative transmission phase. In each of the two interfering paths we induce a quantum dot. The number of electrons in the two dots can be controlled independently. The transmission phase is measured as electrons are added to or taken away fr

Ellak Somfai, Robin C. Ball, Jason P. DeVita, Leonard M. Sander

We performed extensive numerical simulation of diffusion-limited aggregation in two dimensional channel geometry. Contrary to earlier claims, the measured fractal dimension D = 1.712 +- 0.002 and its leading correction to scaling are the same as in the radial case. The average cluster, defined as the average conformal map, is similar but not identical to Saf

S. Park, D. N. Burrows, S. A. Zhekov, E. Michael

We report on the results of our monitoring program of the X-ray remnant of supernova 1987A with the {\it Chandra X-Ray Observatory}. We have performed two new observations during the {\it Chandra} Cycle 3 period, bringing the total to six monitoring observations over the past three years. These six observations provide a detailed time history of the birth of

F. D'Amico, W. A. Heindl, R. E. Rothschild

We have analyzed the long pointed observations of the Z sources in the Rossi X-Ray Timing Explorer (RXTE) public archive to study the high energy emission in those sources. Our analysis is concentrated on the High Energy X--Ray Timing Experiment (HEXTE) waveband, since we are primarily interested in studying the hard X-ray (i.e., E > 20 keV) production in th

Bing Zhang, Steinn Sigurdsson

Planet-planet collisions are expected during the early stages of the formation of extra-solar planets, and are also possible in mature planetary systems through secular planet-planet perturbations. We investigate the electromagnetic signals accompanied with these planetary collisions and their event rate, and explore the possibility of directly detecting suc

S. P. Reynolds

Recent observations of non-thermal X-rays from supernova remnants have been attributed to synchrotron radiation from the loss-steepened tail of a non-thermal distribution of electrons accelerated at the remnant blast wave. In diffusive shock acceleration, the maximum particle energy depends on the energy-dependence of the diffusion coefficient kappa. Most wo

S. Parete-Koon, W. R. Hix, M. S. Smith, S. Starrfield

Proton capture by 17F plays an important role in the synthesis of nuclei in nova explosions. A revised rate for this reaction, based on a measurement of the 1H(17F,p)17F excitation function using a radioactive 17F beam at ORNL's Holifield Radioactive Ion Beam Facility, is used to calculate the nucleosynthesis in nova outbursts on the surfaces of 1.25 and

A. K. Harding, P. L. Gonthier, I. A. Grenier, C. A. Perrot

The EGRET telescope on the Compton Gamma-Ray Observatory detected over 200 sources and the majority of these are still unidentified. At least three subpopulations of EGRET sources have been associated with the Galaxy: bright sources lying along the Galactic plane, weaker sources spatially correlated with the Gould Belt and a high-latitude, halo population. M

M. P. Redman, Z. A. Al-Mostafa, J. Meaburn, M. Bryce

Echelle spectroscopy has been carried out towards a sample region of the halo of the giant HII region 30 Doradus in the Large Magellanic Cloud. This new kinematical data is the amongst the most sensitive yet obtained for this nebula and reveals a wealth of faint, complex high speed features. These are interpreted in terms of localised shells due to individua

T. J. -L. Courvoisier, V. Beckmann, G. Bourban, J. Chenevez

INTEGRAL has observed the bright quasar 3C 273 on 3 epochs in January 2003 as one of the first observations of the open programme. The observation on January 5 was simultaneous with RXTE and XMM-Newton observations. We present here a first analysis of the continuum emission as observed by these 3 satellites in the band from 3 keV to 500 keV. The continuum sp

Vladislav V. Izmodenov, Dmitry B. Alexashov

Physical processes in the tail of the solar wind interaction region with the partially ionized local interstellar medium are investigated in a framework of the self-consistent kinetic-gas dynamic model. It is shown that the charge exchange process of the hydrogen atoms with the plasma protons results in suppression of the gas dynamic instabilities and disapp

Vlad Izmodenov, Yury G. Malama, George Gloeckler, Johannes Geiss

The Sun is moving through a warm ($\sim$6500 K) and partly ionized local interstellar cloud (LIC) with a velocity of $\sim$26 km/s. Recent measurements of the ionization of the LIC (Wolff et al., 1999) suggest that interstellar helium in the vicinity of the Sun is 30-40 % ionized, while interstellar hydrogen is less ionized. Consequently, interstellar helium

J. H. van Gorkom

In recent years a wealth of data and detailed hydrodynamical simulations have appeared that show the effects of interactions between the ICM and galaxies. Single dish observations show that cluster galaxies are deficient in their HI content out to 2 Abell radii. The deficient galaxies tend to be on radial orbits. Imaging of the HI distribution in individual

W. K. M. Rice, P. J. Armitage, I. A. Bonnell, M. R. Bate

It has already been shown, using a local model, that accretion discs with cooling times t_cool <= 3 Omega^-1 fragment into gravitationally bound objects, while those with cooling times t_cool > 3 Omega^-1 evolve into a quasi-steady state. We present results of three-dimensional simulations that test if the local result still holds globally. We find that the

E. T. Polehampton, J. M. Brown, B. M. Swinyard, J. -P. Baluteau

The frequencies and line strengths of the 2Pi3/2 J=5/2-3/2 rotational transition of 17OH have been calculated from an analysis of its far-infrared laser magnetic resonance spectrum. These results have been used to make the first detection of a pure rotational transition of 17OH in the ISM. Two resolved components of this transition appear in absorption towar

Akio K. Inoue

This paper investigates the evolution of the dust-to-metal ratio in galaxies based on a simple evolution model for the amount of metal and dust with infall. We take into account grain formation in stellar mass-loss gas, grain growth by the accretion of metallic atoms in a cold dense cloud, and grain destruction by SNe shocks. Especially, we propose that the

Kenji Bekki, Duncan A. Forbes, Michael A. Beasley, W. J. Couch

We investigate, via numerical simulations, the tidal stripping and accretion of globular clusters (GCs). In particular, we focus on creating models that simulate the situation for the GC systems of NGC 1404 and NGC 1399 in the Fornax cluster, which have poor (specific frequency $S_{\rm N}$ $\sim$ 2) and rich ($S_{\rm N}$ $\sim$ 10) GC systems respectively. W

J. Kataoka, J. P. Leahy, P. G. Edwards, M. Kino

We report the Chandra detection of an X-ray jet in 3C 15. The peak of the X-ray emission in the jet is 4.1&#39;&#39; (a projected distance of 5.1 kpc) from the nucleus, and coincident with a component previously identified in the radio and optical jets. We examine four models for the X-ray jet emission: (I) weak synchrotron cooling in equip., (II) moderate s

David Lemon, Rosemary F. G. Wyse, Jochen Liske, Simon Driver

We derive a star catalogue generated from the images taken as part of the 37.5 sq. deg Millennium Galaxy Catalogue. These data, alone and together with colours gained from the Sloan Digital Sky Survey Early Data Release, allow the analysis of faint star counts (B(MGC) < 20) at high Galactic latitude (41 < b < 63), as a function of Galactic longitude (239 < l

E. G. Berezhko, L. T. Ksenofontov, V. S. Ptuskin, V. N. Zirakashvili

We study the production of cosmic rays (CRs) in supernova remnants (SNRs), including the reacceleration of background galactic cosmic rays (GCRs) - thus refining the early considerations by Blandford & Ostriker (1980) and Wandel et al. (1987) - and the effects of the nuclear spallation inside the sources (the SNRs). This combines for the first time nuclear s

S. C. Chapman, R. Windhorst, S. Odewahn, H. Yan

We present new Hubble Space Telescope STIS, high-resolution optical imaging of a sample of 13 submillimeter (submm) luminous galaxies, for which the optical emission has been pinpointed either through radio-1.4 GHz or millimeter interferometry. We find a predominance of irregular and complex morphologies in the sample, suggesting that mergers are likely comm

Sidney van den Bergh, Weidong Li, Alexei V. Filippenko

Classifications on the DDO system are given for an additional 231 host galaxies of supernovae that have been discovered during the course of the Lick Observatory Supernova Search with the Katzman Automatic Imaging Telescope (KAIT). This brings the total number of hosts of supernovae discovered (or independently rediscovered) by KAIT, which have so far been c

Thomas Becher, Richard J. Hill, Matthias Neubert

It is argued that soft-collinear effective theory for processes involving both soft and collinear partons, such as exclusive B-meson decays, should include a new mode in addition to soft and collinear fields. These &#34;soft-collinear messengers&#34; can interact with both soft and collinear particles without taking them far off-shell. They thus can communic

L. T. Laursen, K. Z. Stanek

We report results of our precise reduction of the high signal-to-noise VRI observations of the optical afterglow of the gamma-ray burst GRB 020813 obtained by Gladders & Hall with the Magellan 6.5-m telescope 3.9-4.9 hours after the burst. These observations are very well fitted locally by a power-law curve, providing the tightest constraints yet on how smoo

G. Gour, F. C. Khanna, A. Mann, M. Revzen

Two mode squeezed vacuum states allow Bell&#39;s inequality violation (BIQV) for all non-vanishing squeezing parameter $(ζ)$. Maximal violation occurs at $ζ\to \infty$ when the parity of either component averages to zero. For a given entangled {\it two spin} system BIQV is optimized via orientations of the operators entering the Bell operator (cf. S. L. Brau

R. Stompor, M. White

We estimate the effects of low temporal frequency modes in the time stream on sky maps such as expected from the PLANCK experiment -- a satellite mission designed to image the sky in the microwave band. We perform the computations in a semi-analytic way based on a simple model of PLANCK observations, which permits an insight into the structure of noise corre

Edward Shuryak, Ismail Zahed

Recently, a number of intriguing results have been obtained for strongly coupled ${\cal N}=4$ Supersymmetric Yang-Mills theory in vacuum and matter, using the AdS/CFT correspondence. In this work, we provide a physical picture supporting and explaining most of these results within the gauge theory. The modified Coulomb&#39;s law at strong coupling forces sta

Stephen R. Sharpe, Ruth S. Van de Water

It has been proposed that partially quenched chiral perturbation theory can be used together with partially quenched lattice QCD to determine the low-energy constants of real QCD. We point out a complication of this approach and show how it can be resolved. Partial quenching changes the chiral symmetry group and introduces a new independent four-derivative o

D. H. Santamore, A. C. Doherty, M. C. Cross

We investigate a scheme that makes a quantum non-demolition measurement of the excitation level of a mesoscopic mechanical oscillator by utilizing the anharmonic coupling between two elastic beam bending modes. The non-linear coupling between the two modes shifts the resonant frequency of the readout oscillator proportionate to the excitation of the system o

Stephen R. Sharpe

The pseudoscalar ``hairpin&#39;&#39; vertex (i.e. quark-disconnected vertex) plays a key role in quenched chiral perturbation theory. Direct calculations using lattice simulations find that it has a significant dependence on quark mass. I show that this mass dependence can be used to determine the quenched Gasser-Leutwyler constant L5. This complements the c

David Gomez-Ullate, Niky Kamran, Robert Milson

We investigate the backward Darboux transformations (addition of a lowest bound state) of shape-invariant potentials on the line, and classify the subclass of algebraic deformations, those for which the potential and the bound states are simple elementary functions. A countable family, $m=0,1,2,...$, of deformations exists for each family of shape-invariant

V. P. Goncalves, M. V. T. Machado

We calculate the photonuclear production of heavy quarks in ultraperipheral heavy ion collisions. The integrated cross section and the rapidity distribution are computed employing sound high energy QCD formalisms as the collinear and semihard approaches as well as the saturation model. In particular, the color glass condensate (CGC) formalism is also conside

Takashi Hiramatsu, Kazuya Koyama, Atsushi Taruya

We study the evolution of gravitational waves(GWs) after inflation in a brane-world cosmology embedded in five-dimensional anti-de Sitter spacetime. Contrary to the standard four-dimensional results, the GWs at the high-energy regime in brane-world model suffer from the effects of the non-standard cosmological expansion and the excitation of the Kaluza-Klein

Donatella Romano, Monica Tosi, Francesca Matteucci, Cristina Chiappini

The recent determination of the baryon-to-photon ratio from WMAP data by Spergel et al. (2003) allows one to fix with unprecedented precision the primordial abundances of the light elements D, 3He, 4He and 7Li in the framework of the standard model of big bang nucleosynthesis. We adopt these primordial abundances and discuss the implications for Galactic che

Victor Eliashberg

A class of analog computers built from large numbers of microscopic probabilistic machines is discussed. It is postulated that such computers are implemented in biological systems as ensembles of protein molecules. The formalism is based on an abstract computational model referred to as Protein Molecule Machine (PMM). A PMM is a continuous-time first-order M

G. Pacelli Bessa, J. Fabio Montenegro

We prove an extension of a theorem of Barta then we make few geometric applications. We extend Cheng&#39;s lower eigenvalue estimates of normal geodesic balls. We generalize Cheng-Li-Yau eigenvalue estimates of minimal submanifolds of the space forms. We prove an stability theorem for minimal hypersurfaces of the Euclidean space, giving a converse statement

Abhay Ashtekar, Badri Krishnan

A detailed description of how black holes grow in full, non-linear general relativity is presented. The starting point is the notion of dynamical horizons. Expressions of fluxes of energy and angular momentum carried by gravitational waves across these horizons are obtained. Fluxes are local and the energy flux is positive. Change in the horizon area is rela

Y. Koma, M. Koma, E. -M. Ilgenfritz, T. Suzuki

The color-electric flux tube of Abelian-projected (AP) SU(2) lattice gauge theory in the maximally Abelian gauge (MAG) is revisited. It is shown that the lattice Gribov copy effect in the MAG is crucial for the monopole-related parts of the flux-tube profiles. Taking into account both the gauge fixing procedure and the effect of finite quark-antiquark distan

P. Lougovski, E. Solano, H. Walther

We present a probabilistic scheme for generating and purifying maximally-entangled states of two atoms inside an optical cavity via no-photon detection in the output cavity mode, where ideal detectors may not be required. The intermediate mixed states can be continuously &#34;filtered&#34; so as to violate Bell inequalities in a parametrized manner. The sche

G. Laveissiere

Exclusive electroproduction of pi0 mesons on protons in the backward hemisphere has been studied at Q**2 = 1.0 GeV**2 by detecting protons in the forward direction in coincidence with scattered electrons from the 4 GeV electron beam in Jefferson Lab&#39;s Hall A. The data span the range of the total (gamma* p) center-of-mass energy W from the pion production

J. Servantie, P. Gaspard

In this work we develop theoretical and numerical methods of calculation of a dynamic friction coefficient. The theoretical method is based on an adiabatic approximation which allows us to express the dynamic friction coefficient in terms of the time integral of the autocorrelation function of the force between both sliding objects. The motion of the objects

A. Lakhtakia, C. M. Krowne

The time-harmonic electromagnetic responses of (a) a bilayer made of an epsilon-negative layer and a mu-negative layer, and (b) a single layer of a negative phase-velocity material are compared. Provided all layers are electrically thin, a restricted equivalence between (a) and (b) exists. The restricted equivalence depends on the linear polarization state a

P. Werner, W. Zwerger

We investigate quantum effects in the mechanical properties of elastic beams on the nanoscale. Transverse quantum and thermal fluctuations and the nonlinear excitation energies are calculated for beams compressed in longitudinal direction. Near the Euler instability, the system is described by a one dimensional Ginzburg-Landau model where the order parameter

Somdatta Bhattacharya, Sudipta Mukherji, Shibaji Roy

Starting from the non-BPS D$(p+1)$-brane action we derive an effective action in $(p+1)$ space dimensions by studying the fluctuations of various bosonic fields around the time-like tachyonic kink solution (obtained by Wick rotation of the space-like tachyonic kink solution) of the non-BPS brane. In real time this describes the dynamics of a space-like or Eu

Joy Christian

It is argued that the `problem of time&#39; in quantum gravity necessitates a refinement of the local inertial structure of the world, demanding a replacement of the usual Minkowski line element by a 4+2n dimensional pseudo-Euclidean line element, with the extra 2n being the number of internal phase space dimensions of the observed system. In the refined str

James Binney

Evidence is summarized that suggests that when a protogalaxy collapses, a fraction $f$ of its gas fails to heat to the virial temperature, where $f$ is large for haloes less massive than the value $M^*$ associated with $L^*$ galaxies. Stars and galaxies form only from the cool gas fraction. Hot gas is ejected from low-mass systems as in conventional semi-ana

Shouchuan Zhang, Yao-Zhong Zhang

Braided m-Lie algebras induced by multiplication are introduced, which generalize Lie algebras, Lie color algebras and quantum Lie algebras. The necessary and sufficient conditions for the braided m-Lie algebras to be strict Jacobi braided Lie algebras are given. Two classes of braided m-Lie algebras are given, which are generalized matrix braided m-Lie alge

Motoi Endo, Yutaka Sakamura

We estimate contributions of the goldstino supermultiplet to the electric dipole moment (EDM) in the case that the SUSY breaking scale Λ_S is of order the TeV scale. We found that such contributions can saturate the experimental bound if Λ_S is close to the soft mass scale. We also discuss EDM in the gaugino mediated scenario on the warped geometry as an exa

Shinji Tsujikawa, Roy Maartens, Robert Brandenberger

Non-commutative inflation is a modification of standard general relativity inflation which takes into account some effects of the space-time uncertainty principle motivated by ideas from string theory. The corrections to the primordial power spectrum which arise in a model of power-law inflation lead to a suppression of power on large scales, and produce a s

Michal Praszalowicz

The mass of the newly discovered pentaquark is calculated within the framework of the SU(3) Skyrme Model. Various estimates based on the \emph{model independent} approach are compared with the model results and with the Chiral Quark Model. Our discussion shows that $Θ^{+}$ is light with the mass of the order 1.5 GeV.

M. Viel, S. Matarrese, A. Heavens, M. G. Haehnelt

We present a determination of the bispectrum of the flux in the Lyman-alpha forest of QSO absorption spectra obtained from LUQAS which consists of spectra observed with the high resolution Echelle spectrograph UVES. Typical errors on the observed bispectrum as obtained from a jack-knife estimator are ~ 50%. For wavenumbers in the range 0.03 s/km <k < 0.1 s/k

E. Friedman, A. Gal

The energy dependence of chirally expanded pi N isoscalar and isovector amplitudes b_0(E) and b_1(E) respectively, for zero-momentum off shell pions near threshold, is used to impose the minimal substitution requirement E -> E - V_c on the properly constructed pion optical potential within a large-scale fit to 100 pionic-atom data across the periodic table w

Hiroyuki Nakano, Norichika Sago, Misao Sasaki

We discuss the gravitational self-force on a particle in a black hole space-time. For a point particle, the full (bare) self-force diverges. It is known that the metric perturbation induced by a particle can be divided into two parts, the direct part (or the S part) and the tail part (or the R part), in the harmonic gauge, and the regularized self-force is d

Takahiro Miura, Tetsuo Shindou, Eiichi Takasugi

We discuss whether the bi-maximal mixing given at GUT is consistent with the solar mixing at the normal side at the low energy. We consider the radiative corrections due to the tau-Yukawa, the neutrino-Yukawa and the slepton threshold corrections and discuss in what situation the maximal solar angle rotates towards the normal side. In this scheme, the |V_{13

H. Zaraket, V. Bagnulo, J. Kettner, R. Kobes

We present a new adiabatic quantum algorithm for searching over structured databases. The new algorithm is optimized using a simplified complexity analysis.

Heng Fan

Quantum cloning machine for arbitrary mixed states in symmetric subspace is proposed. This quantum cloning machine can be used to copy part of the output state of another quantum cloning machine and is useful in quantum computation and quantum information. The shrinking factor of this quantum cloning achieves the well-known upper bound. When the input is ide

Vladimir V. Kassandrov

Single- and multi-valued solutions of homogeneous Maxwell equations in vacuum are considered, with &#39;&#39;sources&#39;&#39; formed by the (point- or string-like) singularities of the field strengths and, generally, irreducible to any delta-functions&#39; distribution. Maxwell equations themselves are treated as consequences (say, integrability conditions)

John Marriner

The status of stochastic cooling and developments over the years are reviewed with reference to much of the original work. Both theoretical and technological subjects are considered.

A. Loinger

I prove that &#34;quantum&#34; and &#34;Einsteinian gravity&#34; are incompatible concepts. Accordingly, the graviton is a mere object of science fiction.

W. Liu, C. M. Ko

Using hadronic Lagrangians that include the interaction of pentaquark $Θ^+$ baryon with $K$ and $N$, we evaluate the cross sections for its production from meson-proton, proton-proton, and photon-proton reactions near threshold. With empirical coupling constants and form factors, the predicted cross sections are about 1.5 mb in kaon-proton reactions, 0.1 mb

Jiunn-Wei Chen, Martin J. Savage

We examine soft-pion emission in deeply virtual Compton scattering. Contrary to previous claims, we find that the amplitude for soft-pion emission is not directly related to the generalized parton distributions in the nucleon.

J. Adam,, M. T. Pena, A. Stadler

The 3N forces due to pi-rho, pi-sigma and pi-omega exchanges following from the nucleon Born diagrams and diagrams with an intermediate N^{*}(1440) are re-analyzed. The cancellation between pi-sigma and pi-omega forces is rather sensitive to the values of the coupling constants and to the form of the piNN vertex. Experimental uncertainties in the parameters

S. J. Lee, A. Z. Mekjian

The thermodynamic properties of proton rich systems are explored in a mean field approach which is generated from a Skyrme interaction. The addition of Coulomb interactions result in asymmetries which modify the chemical and mechanical instability of the system and its equilibrium properties. These properties are studied for systems with proton fraction $y$

Gabor Szirtes, Zsolt Palotai, Andras Lorincz

The fundamental `plasticity&#39; of the nervous system (i.e high adaptability at different structural levels) is primarily based on Hebbian learning mechanisms that modify the synaptic connections. The modifications rely on neural activity and assign a special dynamic behavior to the neural networks. Another striking feature of the nervous system is that spi

Pavel M. Bleher, Xiaojun Di

The existence of the scaling limit and its universality, for correlations between zeros of {\it Gaussian} random polynomials, or more generally, {\it Gaussian} random sections of powers of a line bundle over a compact manifold has been proved in a great generality in the works [BBL2], [Ha], [BD], [BSZ1]-[BSZ4], and others. In the present work we prove the ex

Adrian Clingher, John W. Morgan

One of the dualities in string theory, the F-theory/heterotic string duality in eight dimensions, predicts an interesting correspondence between two seemingly disparate geometrical objects. On one side of the duality there are elliptically fibered K3 surfaces with section. On the other side, one finds elliptic curves endowed with certain flat connections and

Chunhui Lai

A sequence $S$ is potentially $K_4-e$ graphical if it has a realization containing a $K_4-e$ as a subgraph. Let $σ(K_4-e, n)$ denote the smallest degree sum such that every $n$-term graphical sequence $S$ with $σ(S)\geq σ(K_4-e, n)$ is potentially $K_4-e$ graphical. Gould, Jacobson, Lehel raised the problem of determining the value of $σ(K_4-e, n)$. In this

William Arveson

We show that many invariant subspaces M for d-shifts (S_1,...,S_d) of finite rank have the property that the projection P onto M almost commutes with the S_k in the sense that the commutators PS_k - S_kP belong to the Schatten-von Neumann class L^p for every p > d. In such cases the d-tuple of operators (T_1,...,T_d) obtained by compressing (S_1,...,S_d) to

Anders S. Buch, Richard Rimanyi

We prove a formula for double Schubert and Grothendieck polynomials specialized to two rearrangements of the same set of variables. Our formula generalizes the usual formulas for Schubert and Grothendieck polynomials in terms of RC-graphs, and it gives immediate proofs of many other important properties of these polynomials.

Winfried Bruns, Aldo Conca

We give an introduction to the theory of initial ideals and initial algebras with emphasis on the transfer of structural properties.

A. Alekseev, A. Lachowska

We give an explicit formula for invariant *-products on a wide class of coadjoint orbits. The answer is expressed in terms of the Shapovalov pairing for generalized Verma modules.

Martin Henk

We show that for every lattice packing of $n$-dimensional spheres there exists an $(n/\log_2(n))$-dimensional affine plane which does not meet any of the spheres in their interior, provided $n$ is large enough. Such an affine plane is called a free plane and our result improves on former bounds.

Andrei Okounkov, Rahul Pandharipande

We prove generalized Virasoro constraints for the relative Gromov-Witten theories of all nonsingular target curves. Descendents of the even cohomology classes are studied first by localization, degeneration, and completed cycle methods. Descendents of the odd cohomology are then controlled by monodromy and geometric vanishing relations. As an outcome of our

Joon Hyuk Kang

This paper explains the uniqueness of positive steady state of general Lotka-Volterra competition model of two species of animals in the same environment.

Matilde N. Lalin

The Mahler measures of certain polynomials of up to five variables are given in terms of multiple polylogarithms. Each formula is homogeneous and its weight coincides with the number of variables of the corresponding polynomial.

Guenther Hoermann

We consider the Cauchy problem for a hyperbolic pseudodifferential operator whose symbol is generalized, resembling a representative of a Colombeau generalized function. Such equations arise, for example, after a reduction-decoupling of second-order model systems of differential equations in seismology. We prove existence of a unique generalized solution und

Andrés Viña

Let ${\cal O}$ be a quantizable coadjoint orbit of a semisimple Lie group $G$. Under certain hypotheses we prove that $#(π_1(\text{Ham}({\cal O})))\geq #(Z(G))$, where $\text{Ham}({\cal O})$ is the group of Hamiltonian symplectomorphisms of ${\cal O}$.

Ben Green

Given a set A in Z/NZ we may form a Cayley sum graph G_A on vertex set Z/NZ by joining i to j if and only if i + j is in A. We investigate the extent to which performing this construction with a random set A simulates the generation of a random graph, proving that the clique number of G_A is a.s. O(log N). This shows that Cayley sum graphs can furnish good e

W. Bruns, A Conca

We give an introduction to the theory of determinantal ideals and rings, their Groebner bases, initial ideals and algebras, respectively. The approach is based on the straightening law and the Knuth-Robinson-Schensted correspondence. The article contains a section treating the basic results about the passage to initial ideals and algebras.

Niklas Beisert

In this note we consider higher-loop contributions to the planar dilatation operator of N=4 SYM in the su(2) subsector of two complex scalar fields. We investigate the constraints on the form of this object due to interactions of two excitations in the BMN limit. We then consider two scenarios to uniquely fix some higher-loop contributions: (i) Higher-loop i

David Kutasov, Andrei Parnachev, David A. Sahakyan

We use recent results of Intriligator and Wecht [hep-th/0304128] to study the phase structure of $\NN=1$ super Yang-Mills theory with gauge group $SU(N_c)$, a chiral superfield in the adjoint, and $N_f$ chiral superfields in the fundamental representation of the gauge group. Our discussion sheds new light on [hep-th/0304128] and supports the conjecture that

S. S. Xulu

Energy-momentum is an important conserved quantity whose definition has been a focus of many investigations in general relativity. Unfortunately, there is still no generally accepted definition of energy and momentum in general relativity. Attempts aimed at finding a quantity for describing distribution of energy-momentum due to matter, non-gravitational and

Ashoke Sen

Recent investigations involving the decay of unstable D-branes in string theory suggest that the tree level open string theory which describes the dynamics of the D-brane already knows about the closed string states produced in the decay of the brane. We propose a specific conjecture involving quantum open string field theory to explain this classical result