March 2001 arXiv papers — page 26

R. T. Thew, W. J. Munro

There has been much discussion recently regarding entanglement transformations in terms of local filtering operations and whether the optimal entanglement for an arbitrary two-qubit state could be realised. We introduce an experimentally realisable scheme for manipulating the entanglement of an arbitrary state of two polarisation entangled qubits. This schem

Jiangfeng Du, Hui Li, Xiaodong Xu, Mingjun Shi

Recently Quantum Battle of The Sexes Game has been studied by Luca Marinatto and Tullio Weber. Yet some important problems exist in their scheme. Here we propose a new scheme to quantize Battle of The Sexes Game, and this scheme will truly remove the dilemma that exists in the classical form of the game.

F. H. Koenemann

The thermodynamic definition of pressure P = dU/dV is one form of the principle that in a given state, the mass in V and potential are proportional. Subject of this communication is the significance of this principle for the understanding of Cauchy stress.

Ernst Karl Kunst

Beside the rise of total cross sections or interaction radii of colliding high energetic particles and the shrinkage of mean-free-paths of ultra relativistic particles (nucleii) in material media (anomalons), which have been shown to be of special relativistic origin [1], still other phenomena in high energy physics may arise from relativistic kinematics. In

Chaohong Lee, Yiwu Duan, Wing-Ki Liu, Jian-Min Yuan

Based upon our previous works (Eur.Phys.J.D 6, 319(1999); Chin.Phys.Lett. 18, 236(2001)), we develop a classical approach to calculate the high-order harmonic generation of the laser driven atoms and molecules. The Coulomb singularities in the system have been removed by a regularization procedure. Action-angle variables have been used to generate the initia

L. G. Moretto, J. B. Elliott, L. Phair, G. J. Wozniak

The origin of predicted and observed anomalies in caloric curves of nuclei and other mesoscopic systems is investigated. It is shown that a straightforward thermodynamical treatment of an evaporating liquid drop leads to a backbending in the caloric curve and to negative specific heats in the two phase coexistence region. The cause is found not in the genera

A. Stoimenow

Using the recent Gauss diagram formulas for Vassiliev invariants of Polyak-Viro-Fiedler and combining these formulas with the Bennequin inequality, we prove several inequalities for positive knots relating their Vassiliev invariants, genus and degrees of the Jones polynomial. As a consequence, we prove that for any of the polynomials of Alexander/Conway, Jon

A. Stoimenow

Using the Fiedler-Polyak-Viro Gauss diagram formulas we study the Vassiliev invariants of degree 2 and 3 on almost positive knots. As a consequence we show that the number of almost positive knots of given genus or unknotting number grows polynomially in the crossing number, and also recover and extend, inter alia to their untwisted Whitehead doubles, previo

Uli Walther

We give algorithms for the computation of the algebraic de Rham cohomology of open and closed algebraic sets inside projective space or other smooth complex toric varieties. The methods, which are based on Gröbner basis computations in rings of differential operators, can also be used to compute the cohomology of intersections of smooth closed and open subse

Hans Engler

For a class of scalar partial differential equations that incorporate convection, diffusion, and possibly dispersion in one space and one time dimension, the stability of traveling wave solutions is investigated. If the initial perturbation of the traveling wave profile decays at an algebraic rate, then the solution is shown to converge to a shifted wave pro

C. G. Madonna

In this paper we derive a list of all the possible indecomposable normalized rank--two vector bundles without intermediate cohomology on the prime Fano threefolds and on the complete intersection Calabi Yau threefolds, say $V$, of Picard number $ρ=1$. For any such bundle $\E$, if it exists, we find the projective invariants of the curves $C \subset V$ which

Stéphane Gaussent

Let $G$ denote an adjoint semi-simple group over an algebraically closed field and $T$ a maximal torus of $G$. Following Contou-Carrère [CC], we consider the Bott-Samelson resolution of a Schubert variety as a variety of galleries in the building associated to the group $G$. We first determine a cellular decomposition of this variety analogous to the Bruhat

A. Dembo, I. Kontoyiannis

We present a development of parts of rate-distortion theory and pattern- matching algorithms for lossy data compression, centered around a lossy version of the Asymptotic Equipartition Property (AEP). This treatment closely parallels the corresponding development in lossless compression, a point of view that was advanced in an important paper of Wyner and Zi

Malgorzata Rowicka-Kudlicka

We find all unitary representations of the quantum "ax+b" group. It turns out that this quantum group is selfdual in the sense that all unitary representations are 'numbered' by elements of the same group. Moreover, we discover the formula for all unitary representations involving S.L. Woronowicz's quantum exponential function.

R. Jackiw

I recall my collaboration with David Gross. A result about descendants of the chiral anomaly is presented: Chern-Simons terms can be written as total derivatives.

J. Kamnitzer, R. B. Mann

We describe in superspace a classical theory of of two dimensional $(1,1)$ dilaton supergravity coupled to a super-Liouville field, and find exact super black hole solutions to the field equations that have non-constant curvature. We consider the possibility that a gravitini condensate forms and look at the implications for the resultant spacetime structure.

Lies De Fosse, Paul Koerber, Alexander Sevrin

Starting from BPS solutions to Yang-Mills which define a stable holomorphic vector bundle, we investigate its deformations. Assuming slowly varying fieldstrengths, we find in the abelian case a unique deformation given by the abelian Born-Infeld action. We obtain the deformed Donaldson-Uhlenbeck-Yau stability condition to all orders in alpha'. This resul

Alejandro Ayala, Adnan Bashir

We evaluate the fermion-photon vertex in QED at the one loop level in Hard Thermal Loop approximation and write it in covariant form. The complete vertex can be expanded in terms of 32 basis vectors. As is well known, the fermion-photon vertex and the fermion propagator are related through a Ward-Takahashi Identity (WTI). This relation splits the vertex into

Antonio Palazzo

Large mixing MSW solutions to the solar neutrino problem appear to be currently favored by the data. We discuss the possibility of discriminating them by means of present and future experiments. In particular, we show that the study of energy and time dependence of the Earth regeneration effect can be useful in this respect.

A. Marrone

Solutions to the atmospheric neutrino anomaly which smoothly interpolate between nu_mu -> nu_tau and nu_mu -> nu_s oscillations are studied. It is shown that, although the Super-Kamiokande data disfavor the pure nu_mu -> nu_s channel, one cannot exclude sizable amplitude for the nu_mu -> nu_s channel in addition to nu_mu -> nu_tau oscillations.

I. Dadic

We continue to study out of equilibrium TFT with switching on the interaction occurring at finite time. We exploit the concept of projected function (PF) and Wigner transform of projected function (WTPF). WTPF's are bare propagators, one-loop self-energies, retarded and advanced components of the resummed propagator. Among WTPF's convolution product

M. Koike, T. Ota, J. Sato

We study the optimal setup for observation of the CP asymmetry in neutrino factory experiments --- the baseline length, the muon energy and the analysis method. First, we point out that the statistical quantity which has been used in previous works doesn't represent the CP asymmetry. Then we propose the more suitable quantity, $\equiv χ^{2}_{2} $, which

Thomas J. Weiler

The observation of twenty cosmic-ray air-showers at and above 10^{20} eV poses fascinating problems for particle astrophysics: how the primary particles are accelerated to these energies, how the primaries get here through the 2.7K microwave background filling the Universe, and how the highest-energy events exhibit clustering on few-degree angular scales on

Guo-Li Wang, Tai-Fu Feng, Chao-Hsi Chang

The radiative corrections to the pure leptonic decay $D_s{\longrightarrow} {\ell}{ν}_{\ell}$ up-to one-loop order is presented. We find the virtual photon loop corrections to $D_s{\longrightarrow} τ{ν}_τ$ is negative and the corresponding branching ratio is larger than $3.51\times 10^{-3}$. Considering the possible experimental resolutions, our prediction of

Michael Creutz

After mentioning some of the difficulties arising in lattice gauge theory from chiral symmetry, I discuss one of the recent attempts to resolve these issues using fermionic surface states in an extra space-time dimension. This picture can be understood in terms of end states on a simple ladder molecule.

K. Abe, M. Satpathy, H. Yamamoto

When both B0 and B0bar can decay to the same final state composed of two vectors, the interference between them and those among three polarization states result in intricate phenomena. In this note we derive the time and angular distributions for general B to Va Vb processes in a form convenient for actual analyses. We then apply them to specific examples an

Lior M. Burko, Yuk Tung Liu

We study the self force acting on a particle endowed with scalar charge, which is held static (with respect to an undragged, static observer at infinity) outside a stationary, axially-symmetric black hole. We find that the acceleration due to the self force is in the same direction as the black hole's spin, and diverges when the particle approaches the o

L. Herrera, A. Di Prisco, J. Ibanez

Two possible interpretations of FRW cosmologies (perfect fluid or dissipative fluid)are considered as consecutive phases of the system. Necessary conditions are found, for the transition from perfect fluid to dissipative regime to occur, bringing out the conspicuous role played by a particular state of the system (the ''critical point '').

Paul M. Aoki, Ian E. Smith, James D. Thornton

The Harland document management system implements a data model in which document (object) structure can be altered by mixin-style multiple inheritance at any time. This kind of structural fluidity has long been supported by knowledge-base management systems, but its use has primarily been in support of reasoning and inference. In this paper, we report our ex

Leonid Peshkin, Nicolas Meuleau, Leslie Kaelbling

In order for an agent to perform well in partially observable domains, it is usually necessary for actions to depend on the history of observations. In this paper, we explore a {\it stigmergic} approach, in which the agent's actions include the ability to set and clear bits in an external memory, and the external memory is included as part of the input t

Petro M. Gopych

A new three-stage computer artificial neural network model of the tip-of-the-tongue phenomenon is proposed. Each word's node is build from some interconnected learned auto-associative two-layer neural networks each of which represents separate word's semantic, lexical, or phonological components. The model synthesizes memory, psycholinguistic, and me

Yi-Dong Shen, Li-Yan Yuan, Jia-Huai You

Global SLS-resolution and SLG-resolution are two representative mechanisms for top-down evaluation of the well-founded semantics of general logic programs. Global SLS-resolution is linear for query evaluation but suffers from infinite loops and redundant computations. In contrast, SLG-resolution resolves infinite loops and redundant computations by means of

Kwangsik Nho, Efstratios Manousakis

We have studied the thermal conductivity of confined superfluids on a bar-like geometry. We use the planar magnet lattice model on a lattice $H\times H\times L$ with $L \gg H$. We have applied open boundary conditions on the bar sides (the confined directions of length $H$) and periodic along the long direction. We have adopted a hybrid Monte Carlo algorithm

Jairo Sinova, Geoff Canright

We investigate the phase structure of the random-field Ising model with a bimodal random field distribution. Our aim is to test for the possibility of an equilibrium spin-glass phase, and for replica symmetry breaking (RSB) within such a phase. We study a low-temperature region where the spin-glass phase is thought to occur, but which has received little num

J. D. Jorgensen, D. G. Hinks, S. Short

We have determined the structural properties of the superconducting compound MgB2 as a function of temperature from 11 K to 297 K and as a function of hydrostatic pressure up to 0.62 GPa using neutron powder diffraction. This compound, when compared to other diborides with the same structure, is characterized by unusually large anisotropies of both the therm

J. K. Freericks, B. K. Nikolic, P. Miller

We tune the barrier of a Josephson junction through a zero-temperature metal-insulator transition and study the thermodynamic behavior of the junction in the proximity of the quantum-critical point. We examine a short-coherence-length superconductor and a barrier (that is described by a Falicov-Kimball model) using the local approximation and dynamical mean-

Corey W. Bettenhausen, Wade C. Bowie, Michael R. Geller

Elasticity theory provides an accurate description of the long-wavelength vibrational dynamics of homogeneous crystalline solids, and with supplemental boundary conditions on the displacement field can also be applied to abrupt heterojunctions and interfaces. The conventional interface boundary conditions, or connection rules, require that the displacement f

A. E. Allahverdyan, Th. M. Nieuwenhuizen

The kinetic theory of a self-gravitating system is considered in the framework of Bhatnager-Gross-Krook model. This approach offers a unique and tractable setup for studying the central, collision-dominated region of the system, as well as its outer almost collisionless part. Stationary non-equilibrium states of the system are considered and several differen

R. Osborn, E. A. Goremychkin, A. I. Kolesnikov, D. G. Hinks

We report inelastic neutron scattering measurements of the phonon density-of-states in Mg11B2, which has a superconducting transition at 39.2 K. The acoustic phonons extend in energy to 36 meV, and there are highly dispersive optic branches peaking at 54, 78, 89 and 97 meV. A simple Born-von Karman model is able to reproduce the mode energies, and provides a

Th. M. Nieuwenhuizen

A framework for the non-equilibrium thermodynamics of glasses is discussed. It also explains the non-equilibrium thermodynamics of a black hole isolated from matter. The first and second laws of black dynamics and black hole thermodynamics are shown to coincide, while the third laws deal with different issues.

K. Kral, Z. Khas

Electron relaxation in quantum dots is studied theoretically in polar semiconductor materials, with an emphasis put on the phonon-bottleneck problem and electron-LO-phonon coupling. The theory is based on multiphonon states of the electron-LO-phonon system and the self-consistent Tamm-Dancoff approximation is used for the electronic self-energy. Electronic r

C. Panagopoulos, B. D. Rainford, T. Xiang, C. A. Scott

We have measured the magnetic penetration depth of the recently discovered binary superconductor MgB_2 using muon spin rotation and low field $ac$-susceptibility. From the damping of the muon precession signal we find the penetration depth at zero temperature is about 85nm. The low temperature penetration depth shows a quadratic temperature dependence, indic

X. -W. Guan, A. Foerster, J. Links, H. -Q Zhou

A new integrable model which is a variant of the one-dimensional Hubbard model is proposed. The integrability of the model is verified by presenting the associated quantum R-matrix which satisfies the Yang-Baxter equation. We argue that the new model possesses the SO(4) algebra symmetry, which contains a representation of the $η$-pairing SU(2) algebra and a

L. M. Fisher, P. E. Goa, M. Baziljevich, T. H. Johansen

The macroturbulence instability observed in fluxline systems during remagnetization of superconductors is explained. It is shown that when a region with flux is invaded by antiflux the interface can become unstable if there is a relative tangential flux motion. This condition occurs at the interface when the viscosity is anisotropic, e.g., due to flux guidin

G. Jackeli, J. Ranninger

We study the superfluid properties of a system of interacting bosons on a lattice which, moreover, are coupled to the vibrational modes of this lattice, treated here in terms of Einstein phonon model. The ground state corresponds to two correlated condensates: that of the bosons and that of the phonons. Two competing effects determine the common collective s

J. D. M. Champion, S. T. Bramwell, P. C. W. Holdsworth, M. J. Harris

The Ising-like spin ice model, with a macroscopically degenerate ground state, has been shown to be approximated by several real materials. Here we investigate a model related to spin ice, in which the Ising spins are replaced by classical Heisenberg spins. These populate a cubic pyrochlore lattice and are coupled to nearest neighbours by a ferromagnetic exc

Fabio Bernardini, Vincenzo Fiorentini

We study the dependence of macroscopic polarization on composition and strain in wurtzite III-V nitride ternary alloys using ab initio density-functional techniques. The spontaneous polarization is characterized by a large bowing, strongly dependent on the alloy microscopic structure. The bowing is due to the different response of the bulk binaries to hydros

E. Schachinger, J. P. Carbotte, D. N. Basov

We report an Eliashberg analysis of the electron dynamics in YBa_2Cu_3O_6.95. The magnetic resonance at 41 meV couples to charge carriers and defines the characteristic shape in energy of the scattering rate τ^{-1}(T,ω) which allows us to construct the charge-spin spectral density I^2χ(ω,T) at temperature T. The T dependence of the weight under the resonance

D. H. Lu, D. L. Feng, N. P. Armitage, K. M. Shen

With significantly improved sample quality and instrumental resolution, we clearly identify in the (pi,0) ARPES spectra from YBa2Cu3O6.993, in the superconducting state, the long-sought `peak-dip-hump' structure. This advance allows us to investigate the large a-b anisotropy of the in-plane electronic structure including, in particular, a 50% difference

Eric Li, J. J. Li, R. P. Sharma, S. B. Ogale

Femto-second optical pair breaking spectroscopy is performed on optimally doped YBa2Cu3O7-delta near 1.5eV. Dramatic photon energy dependence with a sharp triplet fine structure is seen for the first time. The peak separations are attributable to the reported phonon and magnetic excitations in the system. The power dependence is non-linear with differing exp

Kicheon Kang, Luis Craco

Phase-sensitive transport through a quantum dot coupled to an Aharonov-Bohm ring is analyzed. In this geometry the spectral density of states is directly related to the conductance. It is shown that the Kondo resonance depends on the phase and on the total number of electrons (modulo 4) in the mesoscopic ring. The effect of the discrete level spacing in the

Robert Konik, Hubert Saleur, Andreas Ludwig

In this work we exploit the integrability of the two-lead Anderson model to compute transport properties of a quantum dot, in and out of equilibrium. Our method combines the properties of integrable scattering together with a Landauer-Buttiker formalism. Although we use integrability, the nature of the problem is such that our results are not generically exa

I. L. Aleiner, B. L. Altshuler, Y. M. Galperin

We discuss the comment by Zarand and Zawadowski (cond-mat/0009283) on our preprint cond-mat/0007430 where it has been shown that the strong coupling regime for the two-channel Kondo model of two level system can be never realized for any realistic microscopic description. The authors of the comment state that the Kondo temperature can be substantially increa

Liang-Xin Li

We have studied the band and optical properties of self-assembled quantum wires. In particular, the band structures and optical matrix elements of strained multiple quantum-wires (QWR's) are investigated theoretically via the effective bond-orbital model(EBOM), which takes into account the effects of valence-band anisotropy and the band mixing. It is fou

Wei Bao, P. G. Pagliuso, J. L. Sarrao, J. D. Thompson

Magnetic structure of the heavy fermion antiferromagnet Ce2RhIn8 is determined using neutron diffraction.

J. H. Fan, K. S. Cheng, L. Zhang

BL Lacertae objects are an extreme subclass of AGNs showing rapid and large-amplitude variability, high and variable polarization, and core-dominated radio emissions. If a strong beaming effect is the cause of the extreme observation properties, one would expect that these properties would be correlated with each other. Based on the relativistic beaming mode

J. E. McClintock, C. A. Haswell, M. R. Garcia, J. J. Drake

The X-ray nova XTE J1118+480 suffers minimal extinction (b = 62 degrees) and therefore represents an outstanding opportunity for multiwavelength studies. Hynes et al. (2000) conducted the first such study, which was centered on 2000 April 8 using UKIRT, EUVE, HST and RXTE. On 2000 April 18, the Chandra X-ray Observatory obtained data coincident with a second

Zoltan Haiman, Rennan Barkana, Jeremiah P. Ostriker

Warm Dark Matter (WDM) models have recently been resurrected to resolve apparent conflicts of Cold Dark Matter (DM) models with observations. Endowing the DM particles with non-negligible velocities causes free-streaming, which suppresses the primordial power spectrum on small scales. The choice of a root-mean-square velocity dispersion v(rms) = 0.05 km/s at

Zoltan Haiman, Joseph J. Mohr, Gilbert P. Holder

Over the coming decade, the observational samples available for studies of cluster abundance evolution will increase from tens to hundreds, or possibly to thousands, of clusters. Here we assess the power of future surveys to determine cosmological parameters. We quantify the statistical differences among cosmologies, including the effects of the cosmic equat

R. R. J. Antonucci

Optical spectropolarimetry and broadband polarimetry in other wavebands has been a key to understanding many diverse aspects of AGN. In some cases polarization is due to synchrotron radiation, and in other cases it's due to scattering. Recognition of relativistically beamed optical synchrotron emission by polarization was vital for understanding blazars

Michael E. Jones, Alastair C. Edge, Keith Grainge, William F. Grainger

We have observed the Sunyaev-Zel'dovich effect in a sample of five moderate-redshift clusters with the Ryle Telescope, and used them in conjunction with X-ray imaging and spectral data from ROSAT and ASCA to measure the Hubble constant. This sample was chosen with a strict X-ray flux limit using both the BCS and NORAS cluster catalogues to be well above

Jerome A. Orosz, Erik Kuulkers, Michiel van der Klis, Jeffrey E. McClintock

(shortened) Spectroscopic observations of the fast X-ray transient and superluminal jet source SAX J1819.3-2525 (V4641 Sgr) reveal a best fitting period of P_spect=2.81678 +/- 0.00056 days and a semiamplitude of K_2=211.0 +/- 3.1 km/sec. The optical mass function is f(M)=2.74 +/- 0.12 solar masses. We find a photometric period of P_photo=2.81730 +/- 0.00001

A. A. Esin, J. E. McClintock, J. J. Drake, M. R. Garcia

Based on recent multiwavelength observations of the new X-ray nova XTE J1118+480, we can place strong constraints on the geometry of the accretion flow in which a low/hard state spectrum, characteristic of an accreting black hole binary, is produced. We argue that the absence of any soft blackbody-like component in the X-ray band implies the existence of an

Nicholas D. Morgan, George Chartas, Michael Malm, Mark W. Bautz

We present results from X-ray observations of the quadruply lensed quasar RX J0911.4+0551 using data obtained with the Advanced CCD Imaging Spectrometer (ACIS) on board the Chandra X-ray Observatory. The 29 ks observation detects a total of ~404 X-ray photons (0.3 to 7.0 keV) from the four images of the lensed quasar. Deconvolution of the aspect corrected da

P. J. E. Peebles

Correlation functions and related statistics have been favorite measures of the distributions of extragalactic objects ever since people started analyzing the clustering of the galaxies in the 1930s. I review the evolving reasons for this choice, and comment on some of the present issues in the application and interpretation of these statistics, with particu

Neil Trentham, R. Brent Tully, Marc A. W. Verheijen

Results are presented of a deep optical survey of the Ursa Major Cluster, a spiral-rich cluster of galaxies at a distance of 18.6 Mpc which contains about 30% of the light but only 5% of the mass of the nearby Virgo Cluster. Fields around known cluster members and a pattern of blind fields along the major and minor axes of the cluster were studied with mosai

Jonathan Granot, Mark Miller, Tsvi Piran, Wai-Mo Suen

We perform fully relativistic hydrodynamic simulations of the deceleration and lateral expansion of a relativistic jet as it expands into an ambient medium. The hydrodynamic calculations use a 2D adaptive mesh refinement (AMR) code, which provides adequate resolution of the thin shell of matter behind the shock. We find that the sideways propagation is diffe

R. D. Blum, A. Damineli, P. S. Conti

We present near infrared (J, H, and K) photometry and moderate resolution (lambda/Deltalambda = 3000) K-band spectroscopy of the embedded stellar cluster in the giant H II region W31. Four of the brightest five cluster members are early O--type stars based on their spectra. We derive a spectro--photometric distance for W31 of 3.4 +/- 0.3 kpc using these new

Naomi Hirano, Yoshiaki Taniguchi

We present the CO J=6-5, 4-3, and 3-2 spectra from the blueshifted gas of the outflow driven by the low-mass class 0 protostar in the L1157 dark cloud. Strong submillimeter CO emission lines with T_mb > 30 K have been detected at 63" (~0.13 pc) south from the protostar. It is remarkable that the blue wings in the submillimeter lines are stronger by a fac

S. Hony, C. Van Kerckhoven, E. Peeters, A. G. G. M. Tielens

We present 10-15 micron spectra of a sample of H II regions, YSOs and evolved stars that show strong unidentified infrared emission features, obtained with the ISO/SWS spectrograph on-board ISO. These spectra reveal a plethora of emission features with bands at 11.0, 11.2, 12.0, 12.7, 13.5 and 14.2 micron. These features are observed to vary considerably in

J. Vinko, L. L. Kiss, B. Csak, G. Furesz

We present medium resolution (lambda/Delta lambda = 2500) optical spectroscopy of SN 1999by in NGC 2841 made around its light maximum. The depth ratio of the two Si II features at 5800 AA and 6150 AA being R(SiII) approx. 0.63 at maximum indicates that this SN belongs to the peculiar, sub-luminous SNe Ia. Radial velocities inferred from the minimum of the 61

Noam Soker

I argue that the large scale departure from axisymmetry of the Eta Carinae nebula can be explained by the binary stars model of Eta Carinae. The companion diverts the wind blown by the primary star, by accreting from the wind and possibly by blowing its own collimated fast wind (CFW). The effect of these processes depends on the orbital separation, hence on

Hee-Won Lee, Yong-Woo Kang, Yong-Ik Byun

In this Letter, we report the detection of an emission feature around 6545 Åin the spectra of the bipolar planetary nebula M2-9 and the symbiotic stars RR Telescopii and He 2-106 and propose to identify it as the He II Raman scattered feature. This feature was predicted by Nussbaumer, Schmid & Vogel (1989), who suggested that it is formed through Raman scatt

L. Zhang, K. S. Cheng, J. H. Fan

Based on the $γ$-ray data of blazars in the third EGRET catalog and radio data at 5 GHz, we studied the correlation between the radio and $γ$-ray luminosities using two statistical methods. The first method was the partial correlation analysis method, which indicates that there exist correlations between the radio and $γ$-ray luminosities in both high and lo

Erin Scott Sheldon, James Annis, Hans Bohringer, Philippe Fischer

We present a lensing study of 42 galaxy clusters imaged in Sloan Digital Sky Survey (SDSS) commissioning data. Cluster candidates are selected optically from SDSS imaging data and confirmed for this study by matching to X-ray sources found independently in the ROSAT all sky survey (RASS). Five color SDSS photometry is used to make accurate photometric redshi

James E. Rhoads

The degree to which gamma ray bursts are collimated is now the dominant uncertainty in their energy requirements and event rates. In this review I begin with the reasons for studying GRB collimation, then discuss existing tests for collimation and their applications to date, and finally outline some possible future tests. The most important conclusions are t

J. P. Lloyd, M. C. Liu, J. R. Graham, M. Enoch

We have undertaken an adaptive optics (AO) imaging survey of extrasolar planetary systems and stars showing interesting radial velocity trends from high precision radial velocity searches. AO increases the resolution and dynamic range of an image, substantially improving the detectability of faint close companions. This survey is sensitive to objects less lu

T. Harada, B. J. Carr, C. A. Goymer

It has been pointed out that the value of the gravitational ``constant'' in the early universe may be different from that at present. In that case, it was conjectured that primordial black holes may ``remember'' the value of the gravitational constant in the early universe. The present analysis shows that this is not the case, at least in cer

B. L. Jensen, J. U. Fynbo, J. Gorosabel, J. Hjorth

We present Ulysses and NEAR data from the detection of the short or intermediate duration (2 s) gamma-ray burst GRB000301C (2000 March 1.41 UT). The gamma-ray burst (GRB) was localised by the Inter Planetary Network (IPN) and RXTE to an area of 50 arcmin^2. A fading optical counterpart was subsequently discovered with the Nordic Optical Telescope (NOT) about

N. Graham, R. L. Jaffe, M. Quandt, H. Weigel

We present a method for computing the one-loop, renormalized quantum energies of symmetrical interfaces of arbitrary dimension and codimension using elementary scattering data. Internal consistency requires finite-energy sum rules relating phase shifts to bound state energies.

U. Aglietti

We present a next-to-leading evaluation of the resummed coefficient function for the shape function. The results confirm our previous leading order analysis, namely that the coefficient function is short-distance-dominated, and allow relating the shape function computed with a non-perturbative technique to the physical QCD distributions.

Zoltan Ligeti, Michael Luke, Mark B. Wise

We propose studying the mechanism of factorization in exclusive decays of the form B->D(*)X by examining the differential decay rate as a function of the invariant mass of the light hadronic state X. If factorization works primarily due to the large N_c limit then its accuracy is not expected to decrease as the X invariant mass increases. However, if factori

R. Ouyed, F. Sannino

A model for Gamma ray bursts inner engine based on quark stars (speculated to exist in nature) is presented. We describe how and why these objects might constitute new candidates for GRB inner engines. At the heart of the model is the onset of exotic phases of quark matter at the surface of such stars, in particular the 2-flavor color superconductivity. A no

Xunya Jiang, C. M. Soukoulis

We demonstrate that a knowledge of the density-of-states and the eigenstates of a random system without gain, in conjunction with the frequency profile of the gain, can accurately predict the mode that will lase first. Its critical pumping rate can be also obtained. It is found that the shape of the wavefunction of the random system remains unchanged as gain

Paul Bird

It is shown that extending Osp(4/1) supergravity to quaternion co-ordinates to get HU(4/1) gives the standard model with 3 generations of fermions, U(1)xSU(2)xSU(3) bosons plus 2 gravitinos, 1 graviton, and nothing else. It is shown using the method of components that this is the largest supergravity theory possible. Briefly, we look at how this relates to 1

R. Tomas, H. Päs, J. W. F. Valle

We discuss limits on neutrino-Majoron couplings both from laboratory experiments as well as from astrophysics. They apply to the simplest class of Majoron models which covers a variety of possibilities where neutrinos acquire mass either via a seesaw-type scheme or via radiative corrections. By adopting a general framework including CP phases we generalize b

A. A. Barrientos Bendezu, B. A. Kniehl

We study the hadroproduction of two neutral Higgs bosons in the minimal supersymmetric extension of the standard model, which provides a handle on the trilinear Higgs couplings. We include the contributions from quark-antiquark annihilation at the tree level and those from gluon-gluon fusion, which proceeds via quark and squark loops. We list compact results

Christopher J. Miller, Robert C. Nichol, David J. Batuski

We present a joint analysis of the power spectra of density fluctuations from three independent cosmological redshift surveys; the PSCz galaxy catalog, the APM galaxy cluster catalog and the Abell/ACO cluster catalog. Over the range 0.03 <= k <= 0.15 h/Mpc,the amplitudes of these three power spectra are related through a simple linear biasing model with b =

S. Kümmel, M. Brack

A partial differential eigenvalue equation for the density displacement fields associated with electronic excitations is derived in the framework of density functional theory. Our quantum fluid-dynamical approach is based on a variational principle and the Kohn-Sham ground-state energy functional, using only the occupied Kohn-Sham orbitals. It allows for an

S. L. Li, H. H. Wen, Z. W. Zhao, Y. M. Ni

The lower critical field $H_{c1}$ has been carefully measured on a well shaped cylindrical sample of the new superconductor $MgB_2$ fabricated by high pressure synthesis. The penetration depth $λ$ is calculated from the $H_{c1}$ data. It is found that a linear relation of $H_{c1}(T)$ appears in whole temperature region below $T_c$. Furthermore a finite slope

Xavier Calmet, Harald Fritzsch, Dirk Holtmannspotter

The leptons are viewed as composite objects, exhibiting anomalous magnetic moments and anomalous flavor-changing transition moments. The decay $μ\to e γ$ is expected to occur with a branching ratio of the same order as the present experimental limit.

M. Caffo, H. Czyz, E. Remiddi

The threshold behavior of the master amplitudes for two loop sunrise self-mass graph is studied by solving the system of differential equations, which they satisfy. The expansion at the threshold of the master amplitudes is obtained analytically for arbitrary masses.

X. H. Chen, Y. Y. Xue, R. L. Meng, C. W. Chu

The penetration depth lambda of MgB2 was deduced from both the ac susceptibility chi and the magnetization M(H) of sorted powders. The good agreement between the two sets of data without geometric correction for the grain orientation suggests that MgB2 is an isotropic superconductor.

Jens Kortus, C. Stephen Hellberg, Mark R. Pederson

We report first-principles all-electron density-functional based studies of the electronic structure, magnetic ordering and anisotropy for the V$_{15}$ molecular magnet. From these calculations, we determine a Heisenberg Hamiltonian with four antiferromagnetic and one {\em ferromagnetic} coupling. We perform direct diagonalization to determine the temperatur

M. Capdequi-Peyranère, M. C. Rodriguez

The goal of this article is to derive the Feynman rules involving charginos, neutralinos, double charged gauge bosons and sleptons in a 3-3-1 supersymmetric model. Using these Feynman rules we will calculate the production of a double charged chargino with a neutralino and also the production of a pair of single charged charginos, both in an electron- electr

P. Tozzi, P. Rosati, M. Nonino, J. Bergeron

We present results from 300 ks of X-ray observations of the Chandra Deep Field South. The field of the four combined exposures is now 0.1035 deg^2 and we reach a flux limit of 10^{-16} erg s^{-1} cm^{-2} in the 0.5-2 keV soft band and 10^{-15} erg s^{-1} cm^{-2} in the 2-10 keV hard band, thus a factor 2 fainter than the previous 120 ks exposure. The total c

A. Yu. Kamenshchik, U. Moschella, V. Pasquier

We consider a FRW cosmological model with an exotic fluid known as Chaplygin gas. We show that the resulting evolution of the universe is not in disagreement with the current observation of cosmic acceleration. The model predict an increasing value for the effective cosmological constant.

Marc G. Zacher, Robert Eder, Enrico Arrigoni, Werner Hanke

By comparing single-particle spectral functions of t-J and Hubbard models with recent angle-resolved photoemission (ARPES) results for LSCO and Nd-LSCO, we can decide where holes go as a function of doping, and more specifically, which type of stripe (bond-, site-centered) is present in these materials at a given doping. For dopings greater than about 12% ou

S. Franz, M. Mezard, F. Ricci-Tersenghi, M. Weigt

We introduce a finite-connectivity ferromagnetic model with a three-spin interaction which has a crystalline (ferromagnetic) phase as well as a glass phase. The model is not frustrated, it has a ferromagnetic equilibrium phase at low temperature which is not reached dynamically in a quench from the high-temperature phase. Instead it shows a glass transition

Marek Gazdzicki, Mark I. Gorenstein

In high energy p+p(bar) interactions the mean multiplicity and transverse mass spectra of neutral mesons from eta to Upsilon (m = 0.5 - 10 GeV/c^2) and the transverse mass spectra of pions (m_T > 1 GeV/c^2) reveal a remarkable behaviour: they follow, over more than 10 orders of magnitude, the power-law function:The parameters C and P are energy dependent, bu