May 2003 arXiv papers — page 4

V. V. Vassiliev

During the 2002-2003 observing season the Whipple 10m imaging atmospheric Cerenkov telescope was used to search for dark matter annihilation radiation in four nearby galaxies: M32, M33, Draco, and Ursa Minor. Scientific motivations for this choice of targets are discussed as well as accumulated exposure. The analysis results are to be reported in the confere

P. Rebillot

We report on observations of Markarian 421 made with the Whipple 10m Cerenkov telescope and the RXTE satellite during a multi-wavelength campaign in December 2002 and January 2003, initiated by a Whipple target of opportunity. The observations revealed several flares with flux levels between 1 and 2 times the flux of the Crab Nebula. We will discuss the temp

S. LeBohec

The Whipple 10-m telescope was used to observe M87 since 2000. No significant gamma-ray signal was found and upper limits compared to the HEGRA detection suggest the source may be variable. We found weak evidence for a correlation with the X-ray activity in 2000-2001 but this tendency did not persist in 2002-2003.

S. LeBohec

The Whipple 10m Very High Energy gamma-ray telescope has been used to search for indications of WIMP annihilation in the direction of the globular cluster M15. The upper limits derived constrain the amount of super-symmetric dark matter that may reside in globular clusters.

J. Kildea

We present the results of a search for pulsed TeV emission from the Crab pulsar using 97 hours of data recorded with the high-resolution GRANITE III camera of the Whipple 10 m gamma-ray telescope.

D. Horan

The BL Lacertae object H1426+428 is the most distant, confirmed source of TeV gamma rays. At a redshift of 0.129, its detection at TeV energies has important implications for estimating the density of the extragalactic infra-red background radiation. H1426+428 was observed extensively during the 2001/2002 observing season with the Whipple 10 m gamma-ray tele

D. Horan

The results of observations of 29 BL Lacertae objects taken with the Whipple Observatory 10 m gamma-ray Telescope between 1995 and 2000 are presented.

J. Holder

Strong flares of TeV gamma-ray emission up to a level of ~5 Crab were detected by the Whipple 10 m atmospheric Cerenkov telescope from the BL Lacertae object 1ES1959+650 during May - July 2002. We report here the results of follow up observations during 2002 - 2003.

T. A. Hall

To date three plerionic systems have been detected as emitters of very energetic photons. As part of an ongoing study of pulsar systems at the Whipple observatory, observations of the plerion PSR B1823-13 are being conducted. Observations were made with the Whipple 10 m gamma-ray telescope utilizing the high resolution, 490 pixel camera.

A. Falcone

A recent report from the Milagro collaboration included an all-sky map created using one year of data from Milagro (peak sensitivity at 3-4 TeV for Crab-like spectra). This map included an unidentified excess that was brighter than the Crab and was the second brightest spot on the map. The hot spot was within the error box of the EGRET unidentified source 3E

I. de la Calle Perez

In recent years, blazar surveys at radio and X-ray energies have greatly increased our understanding of this type of active galaxy. The combination of multi-wavelength data has shown that blazars follow a well defined sequence in terms of their broad band spectral properties. Together with increasingly detailed emission models, this information has provided

Steve Kortenkamp, Renu Malhotra, Tatiana Michtchenko

We investigate the survivability of Trojan-type companions of Neptune during primordial radial migration of the giant planets Jupiter, Saturn, Uranus, and Neptune. Loss of Neptune Trojans during planetary migration is not a random diffusion process. Rather, losses occur almost exclusively during discrete episodes when Trojan particles are swept by secondary

Antony A. Stark

Technological advances will allow the placement of many Terahertz detectors at the focal plane of a single telescope. For a telescope of a given diameter and wavelength of operation, there is a limit to the number of usable detectors imposed by diffraction and optical aberrations. These effects can be ameliorated through an optical design where the magnifica

Edwin Bergin, Nuria Calvet, Paola D'Alessio, Gregory J. Herczeg

We show in this Letter that the spectral details of the FUV radiation fields have a large impact on the chemistry of protoplanetary disks surrounding T Tauri stars. We show that the strength of a realistic stellar FUV field is significantly lower than typically assumed in chemical calculations and that the radiation field is dominated by strong line emission

Stephen Hawking

Cosmology from the Top Down.

G. Andreuzzi, A. Bragaglia, M. Tosi, G. Marconi

We present CCD UBVI photometry of the intermediate age open cluster NGC 6939 for three TNG-DOLORES fields. The fields A and B cover the center of the cluster; the third one is located about 30 arcmin away, and is used for field stars decontamination. The V-I, B-V and U-B color-magnitude diagrams (CMDs), obtained joining very different exposures show: i) a Ma

L. Saggese, G. Di Sciascio, M. Iacovacci, S. Mastroianni

The ARGO-YBJ experiment is currently under construction at the Yangbajing Cosmic Ray Laboratory (4300 m a.s.l.). The detector will cover 74 X 78 m^2 with a single layer of Resistive Plate Counters (RPCs), surrounded by a partially instrumented guard ring. Signals from each RPC are picked-up with 80 read out strips 6 cm wide and 62 cm long. These strips allow

Pedro F. Gonzalez-Diaz

Phantom energy which violates the dominant-energy condition and is not excluded by current constraints on the equation of state may be dominating the evolution of the universe now. It has been pointed out that in such a case the fate of the universe may be a big rid where the expansion is so violent that all galaxies, planet and even atomic nuclei will be su

G. Di Sciascio, C. Bleve, T. Di Girolamo, D. Martello

In any EAS array, the rejection of events with shower cores outside the detector boundaries is of great importance. A large difference between the true and the reconstructed shower core positions may lead to a systematic miscalculation of some shower characteristics. Moreover, an accurate determination of the shower core position for selected internal events

Victor I. Denisov, Sergey I. Svertilov

The possibilities of observing some nonlinear electrodynamic effects, which can be manifested in hard emission of X-ray, gamma ray pulsars and magnetars by X-ray and gamma ray astronomy methods are discussed. The angular resolution and sensitivity of modern space observatories give the opportunity to study the nonlinear electrodynamic effects, which can occu

Lawrence M. Krauss

The WMAP satellite has provided a new measurement of the age of the Universe, of $13.7 \pm 0.2$ Gyr. A comparison of this limit with constraints from stellar evolution imply that the oldest globular clusters in the Milky Way galaxy have a reasonable probability of have formed significantly after reionization. At the same time, one can derive a direct {\it up

M. C. Runyan, P. A. R. Ade, J. J. Bock, J. R. Bond

We review the first science results from the Arcminute Cosmology Bolometer Array Receiver (ACBAR); a multifrequency millimeter-wave receiver optimized for observations of the Cosmic Microwave Background (CMB) and the Sunyaev-Zel'dovich (SZ) effect in clusters of galaxies. ACBAR was installed on the 2 m Viper telescope at the South Pole in January 2001 an

E. Schinnerer, T. Boeker, D. S. Meier

We present high spatial resolution (1.2") mm-interferometric observations of the CO(2-1) line emission in the central 300pc of the late-type spiral galaxy IC342. The data, obtained with the Owens Valley Radio Observatory, allow first-time detection of a molecular gas disk that coincides with the luminous young stellar cluster in the nucleus of IC342. The

Jeremy Darling

We investigate the constraints that OH microwave transitions in megamasers and molecular absorbers at cosmological distances may place on the evolution of the fine structure constant alpha=e^2/(hbar c). The centimeter OH transitions are a combination of hyperfine splitting and lambda-doubling that can constrain the cosmic evolution of alpha from a single spe

A. Yoshisato, M. Morikawa, H. Mouri

According to N-body numerical simulations, the radial pairwise velocities of galaxies have negative skewness in the quasi-nonlinear regime. To understand its origin, we calculate the probability distribution function of the radial pairwise velocity using the Zel'dovich approximation, i.e., an analytical approximation for gravitational clustering. The cal

J. S. Arabadjis, M. W. Bautz, G. Arabadjis

Knowledge of the structure of galaxy clusters is essential for an understanding of large scale structure in the universe, and may provide important clues to the nature of dark matter. Moreover, the shape of the dark matter distribution in the cluster core may offer insight into the structure formation process. Unfortunately, cluster cores also tend to be the

Antony Lewis

The full sky cosmic microwave background polarization field can be decomposed into 'electric' (E) and 'magnetic' (B) components that are signatures of distinct physical processes. We give a general construction that achieves separation of E and B modes on arbitrary sections of the sky at the expense of increasing the noise. When E modes are p

Jonathan L. Rosner

Examples are given of some current questions in $b$ physics to which LHC experiments may provide answers. These include (i) the precise determination of parameters of the Cabibbo-Kobayashi-Maskawa (CKM) matrix; (ii) measurements of CKM phases using B decays to CP eigenstates; (iii) the search for direct CP asymmetries in B decays; (iv) rare radiative B decay

D. Besson

Using 13.5 inverse fb of e+e- annihilation data collected with the CLEO II detector we have observed a narrow resonance in the Ds*+pi0 final state, with a mass near 2.46 GeV. The search for such a state was motivated by the recent discovery by the BaBar Collaboration of a narrow state at 2.32 GeV, the DsJ*(2317)+ that decays to Ds+pi0. Reconstructing the Ds+

Graeme Lufkin, Thomas Quinn, James Wadsley, Joachim Stadel

We present three-dimensional self-gravitating smoothed-particle hydrodynamics (SPH) simulations of an isothermal gaseous disc interacting with an embedded planet. Discs of varying stability are simulated with planets ranging from 10 Earth-masses to 2 Jupiter-masses. The SPH technique provides the large dynamic range needed to accurately capture the large sca

F. Canfora, H. -J. Schmidt

A vacuum solution of the Einstein gravitational field equation is given that follows from a general ansatz but fails to follow from it if a certain symmetric matrix is assumed to be in diagonal form from the beginning.

Leszek Szybisz, Ignacio Urrutia

The thickness $W$ and the surface energy $σ_A$ at the free interface of superfluid $^4$He are studied. Results of calculations carried out by using density functionals for cylindrical and spherical systems are presented in a unified way, including a comparison with the behavior of planar slabs. It is found that for large species $W$ is independent of the geo

Henriette Elvang

We construct a supergravity solution describing a charged rotating black ring with S^2xS^1 horizon in a five dimensional asymptotically flat spacetime. In the neutral limit the solution is the rotating black ring recently found by Emparan and Reall. We determine the exact value of the lower bound on J^2/M^3, where J is the angular momentum and M the mass; th

Marcelo D. Marucho, C. A. Garcia Canal, H. Fanchiotti

The Landau distribution as well as its first and second momenta are well suited for describing the energy loss of charged particles traversing a thin layer of matter. At present, just rational approximations and asymptotic expressions for these functions were obtained. In this paper we present a direct calculation of the integral representation of these func

R. Bernabei, P. Belli, F. Cappella, R. Cerulli

DAMA is an observatory for rare processes based on the development and use of various kinds of radiopure scintillators. Several low background set-ups have been realized with passing and many rare processes have been investigated. Main activities are briefly summarized in the following and the main arguments on the results achieved in the investigation of th

A. R. King, K. A. Pounds

We show that black holes accreting at or above the Eddington rate probably produce winds which are optically thick in the continuum, whether in quasars or X-ray binaries. The photospheric radius and outflow speed are proportional to \mo^2 and \mo^-1 respectively, where \mo is the mass outflow rate. The outflow momentum rate is always of order L_Edd/c. Blackb

Olof Barring

The EU DataGrid project workpackage 4 has as an objective to provide the necessary tools for automating the management of medium size to very large computing fabrics. At the end of the second project year subsystems for centralized configuration management (presented at LISA'02) and performance/exception monitoring have been delivered. This will soon be

S. Barsov, I. Lehmann, R. Schleichert, C. Wilkin

The first measurement of the p n -> d omega total cross section has been achieved at mean excess energies of Q = 28 and 57 MeV by using a deuterium cluster-jet target. The momentum of the fast deuteron was measured in the ANKE spectrometer at COSY-Juelich and that of the slow "spectator" proton p(sp) from the p d -> p(sp) d omega reaction in a silico

M. Gurses, Y. Ipekoglu, A. Karasu, C. Senturk

The collision of pure electromagnetic plane waves with collinear polarization in N-dimensional (N=2+n) Einstein-Maxwell theory is considered. A class of exact solutions for the higher dimensional Bell-Szekeres metric is obtained and its singularity structure is examined.

Idris Assani

Let $(X,\mathcal{B},μ, T)$ be a measure preserving system. We prove the pointwise convergence of averages along cubes of $2^{k}-1$ bounded and measurable functions for all $k$.

Stefan Friedl

We give a useful classification of the metabelian unitary representations of pi_1(M_K), where M_K is the result of zero-surgery along a knot K in S^3. We show that certain eta invariants associated to metabelian representations pi_1(M_K) --> U(k) vanish for slice knots and that even more eta invariants vanish for ribbon knots and doubly slice knots. We show

C. P. Dettmann, J. P. Keating, S. D. Prado

The stability of photon trajectories in models of the Universe that have constant spatial curvature is determined by the sign of the curvature: they are exponentially unstable if the curvature is negative and stable if it is positive or zero. We demonstrate that random fluctuations in the curvature provide an additional stabilizing mechanism. This mechanism

Feng Yuan

In a previous paper, we presented the global solution of a new accretion flow model, namely luminous hot accretion flows (LHAFs). In this {\em Letter}, we first show the corresponding thermal equilibrium curve of LHAFs in the mass accretion rate vs. surface density diagram. Then we examine its thermal stability again local perturbations. We find that LHAFs a

Subrata Pal, Scott Pratt

A fast jet propagating through partonic matter loses energy by medium-induced gluon radiation. We propose a method to detect the energy loss of jets and the final-state interaction of the radiated gluons and the jets with the partonic medium. By embedding jets and radiated energy into a parton cascade, we find that the fate of lost jets can be studied by ana

A. G. Doroshkevich, P. D. Naselsky, O. V. Verkhodanov, D. I. Novikov

A new scheme of sky pixelization is developed for CMB maps. The scheme is based on the Gauss--Legendre polynomials zeros and allows one to create strict orthogonal expansion of the map. A corresponding code has been implemented and comparison with other methods has been done.

Won-Ho Kye, Muhan Choi, Myung-Woon Kim, Soo-Young Lee

We investigate synchronization in the presence of delay time modulation for application to communication. We have observed that the robust synchronization is established by a common delay signal and its threshold is presented using Lyapunov exponents analysis. The influence of the delay time modulation in chaotic oscillators is also discussed.

W. Grimus, L. Lavoura

We discuss a neutrino mass matrix $\mathcal{M}_ν$ originally found by Babu, Ma, and Valle (BMV) and show that this mass matrix can be characterized by a simple algebraic relation. From this relation it follows that atmospheric neutrino mixing is exactly maximal while at the same time an arbitrary mixing angle $θ_{13}$ of the lepton mixing matrix $U$ is allow

M. Brunner, C. Bechinger, U. Herz, H. H. von Grunberg

We use video microscopy to study a two-dimensional (2D) model fluid of charged colloidal particles suspended in water and compute the pressure from the measured particle configurations. Direct experimental control over the particle density by means of optical tweezers allows the precise measurement of pressure as a function of density. We compare our data wi

M. Martins Afonso, A. Celani, R. Festa, A. Mazzino

The issue of the parameterization of small scale (``subgrid'') turbulence is addressed in the context of passive scalar transport. We focus on the Kraichnan advection model which lends itself to the analytical investigation of the closure problem. We derive systematically the dynamical equations which rule the evolution of the coarse-grained scalar f

Yoshiaki Kobayashi, Mai Yokoi, Masatoshi Sato

Layered Co oxide NaxCoO2.yH2O with a superconducting transition temperature Tc =4.5 K has been studied by 59Co NQR. The nuclear spin relaxation rate 1/59T1 is nearly proportional to temperature T in the normal state. In the superconducting state, it exhibits the coherence peak and decreases with decreasing T below ~0.8Tc. Detailed comparison of the 1/T1T val

Sanjeev Kumar, Pinaki Majumdar

We study the nanoscale phase coexistence of ferromagnetic metallic (FMM) and antiferromagnetic insulating (AFI) regions by including the effect of AF superexchange and weak disorder in the double exchange model. We use a new Monte Carlo technique, mapping on the disordered spin-fermion problem to an effective short range spin model, with self-consistently co

H. -S. Sim, M. Kataoka, Hangmo Yi, N. Y. Hwang

We propose a general capacitive model for an antidot, which has two localized edge states with different spins in the quantum Hall regime. The capacitive coupling of localized excess charges, which are generated around the antidot due to magnetic flux quantization, and their effective spin fluctuation can result in Coulomb blockade, h/(2e) Aharonov-Bohm osci

B. Jancovici, G. Téllez

The classical (i.e. non-quantum) equilibrium statistical mechanics of a Coulomb fluid living on a pseudosphere (an infinite surface of constant negative curvature) is considered. The Coulomb fluid occupies a large disk communicating with a reservoir (grand-canonical ensemble). The total charge $Q$ on the disk fluctuates. In a macroscopic description, the cha

K. B. Chong, L. B. Kong, LinFeng Chen, L. Yan

Al2O3-Ba0.5Sr0.5TiO3 (Al2O3-BST) thin films, with different Al2O3 contents, were deposited on (100) LaAlO3 substrate by pulsed laser deposition (PLD) technique. The Al2O3-BST films was demosnstrated to be a suitable systems to fabricate ferroelectric thin films with low dielectric loss and higher figure of merit for tunable microwave devices. Pure BST thin f

John McDonald

In hybrid inflation and running mass inflation models it is possible that the inflaton field will fragment into non-topological solitons, resulting in a highly inhomogeneous post-inflation era prior to reheating. In supersymmetric models with a conventional homogeneous post-inflation era, the dynamics of flat direction scalars are determined by cH^{2} correc

Soon-Tae Hong, Joohan Lee, Tae Hoon Lee, Phillial Oh

We study the Hamiltonian structure of the gauge symmetry enhancement in the enlarged CP(N) model coupled with U(2) Chern-Simons term, which contains a free parameter governing explicit symmetry breaking and symmetry enhancement. After giving a general discussion of the geometry of constrained phase space suitable for the symmetry enhancement, we explicitly p

Sera Cremonini

We consider a quantum deformation of the wave equation on a cosmological background as a toy-model for possible trans-Planckian effects. We compute the power spectrum of scalar and tensor fluctuations for power-law inflation, and find a noticeable deviation from the standard result. We consider de Sitter inflation as a special case, and find that the resulti

Won-Ho Kye, Dae-Sic Lee, Sunghwan Rim, Chil-Min Kim

We investigate the characteristics of temporal phase locking states observed in the route to phase synchronization. It is found that before phase synchronization there is a periodic phase synchronization state characterized by periodic appearance of temporal phase locking state and that the state leads to local negativeness in one of the vanishing Lyapunov e

J. F. Corney, Ole Bang

We consider plane waves propagating in quadratic nonlinear slab waveguides with nonlinear quasi-phase-matching gratings. We predict analytically and verify numerically the complete gain spectrum for transverse modulational instability, including hitherto undescribed higher order gain bands.

Daegene Song

We report two key distribution schemes achieved by swapping quantum entanglement. Using two Bell states, two bits of secret key can be shared between two distant parties that play symmetric and equal roles. We also address eavesdropping attacks against the schemes.

S. I. Ipatov, J. C. Mather

The orbital evolution of more than 22000 Jupiter-crossing objects under the gravitational influence of planets was investigated. We found that the mean collision probabilities of Jupiter-crossing objects (from initial orbits close to the orbit of a comet) with the terrestrial planets can differ by more than two orders of magnitude for different comets. For i

Dae-Yup Song, John R. Klauder

The Darbroux transformation is generalized for time-dependent Hamiltonian systems which include a term linear in momentum and a time-dependent mass. The formalism for the $N$-fold application of the transformation is also established, and these formalisms are applied for a general quadratic system (a generalized harmonic oscillator) and a quadratic system wi

F. Herbut

Necessary and sufficient conditions for the existence of a composite-system statistical operator, and, separately, for the possibility of its being correlated or uncorrelated, are derived in terms of its range dimension and the range dimensions of its reduced statistical operators.

Vassili Serov, Arne Keller, Osman Atabek, Nicolas Billy

A detailed theory-versus-experiment comparison is worked out for H$_2^+$ intense laser dissociation, based on angularly resolved photodissociation spectra recently recorded in H.Figger's group. As opposite to other experimental setups, it is an electric discharge (and not an optical excitation) that prepares the molecular ion, with the advantage for the

Netanel H. Lindner, Asher Peres, Daniel R. Terno

The orientation in space of a Cartesian coordinate system can be indicated by the two vectorial constants of motion of a classical Keplerian orbit: the angular momentum and the Laplace-Runge-Lenz vector. In quantum mechanics, the states of a hydrogen atom that mimic classical elliptic orbits are the coherent states of the SO(4) rotation group.It is known how

Alexei Gilchrist, G. J. Milburn, W. J. Munro, Kae Nemoto

We describe a scheme for producing an optical nonlinearity using an interaction with one or more ancilla two-level atomic systems. The nonlinearity, which can be implemented using high efficiency fluorescence shelving measurements, together with general linear transformations is sufficient for simulating arbitrary Hamiltonian evolution on a Fock state qudit.

Jian-Qi Shen

The propagation of monomode photons inside a coiled optical fibre was regarded as a time-dependent quantum evolution process, which gives rise to a geometric phase. It is well known that the investigation of non-adiabatic geometric phases ought to be performed only in the Schrödinger picture. So, the projections of photon spin operators onto the fixed frame

Harry Buhrman, Peter Hoyer, Serge Massar, Hein Roehrig

We use techniques for lower bounds on communication to derive necessary conditions (in terms of detector efficiency or amount of super-luminal communication) for being able to reproduce the quantum correlations occurring in EPR-type experiments with classical local hidden-variable theories. As an application, we consider n parties sharing a GHZ-type state an

Patrick Ilg, Iliya V. Karlin, Alexander N. Gorban

We explore a possible application of the additive generalization of the Boltzmann-Gibbs-Shannon entropy proposed in [A.N. Gorban, I.V. Karlin, Phys. Rev. E, 67:016104 (2003)] to fully developed turbulence. The predicted probability distribution functions are compared with those obtained from Tsallis' entropy and with experimental data. Consequences of th

Andrei P. Kirilyuk

The universal concept of complexity by the dynamic redundance paradigm and the ensuing concept of extended dynamic fractality (physics/9806002) are applied here to higher levels of complexity corresponding to living systems. After recalling the framework of unreduced dynamic complexity and dynamically probabilistic fractality (see also physics/0211071), we c

A. L. Khomkin, I. A. Mulenko

An expression is derived for the free energy of nonideal atomic plasma, which corresponds to exact asymptotic expansions. The analytical dependence of correction for the interaction of free charges on the partition function of atom is found. It is demonstrated that the consistent inclusion of the contribution by excited atomic states to the thermodynamic fun

Holger Mueller, Sven Herrmann, Claus Braxmaier, Stephan Schiller

We report on a new test of Lorentz invariance performed by comparing the resonance frequencies of two orthogonal cryogenic optical resonators subject to Earth's rotation over 1 year. For a possible anisotropy of the speed of light c, we obtain 2.6 +/- 1.7 parts in 10^15. Within the Robertson-Mansouri-Sexl test theory, this implies an isotropy violation p

F. Asiri, F. Le Pimpec, A. Seryi

The vibration stability requirements for the Next Linear Collider (NLC) are far more stringent than for the previous generation of Colliders. To meet these goals, it is imperative that the effects of vibration on NLC Linac components from near-field sources (e.g. compressors, high vacuum equipment, klystrons, modulators, pumps, fans, etc) be well understood.

Armin Bunde, Jan F. Eichner, Rathinaswamy Govindan, Shlomo Havlin

This paper has been withdrawn by the author(s), due to double submission. You can find it under: physics/0208019

P. -Y. Longaretti

The relation between rotating plane Couette and Taylor-Couette flows is clarified. The identity of their linear stability limits is explained by considering the effect of the Coriolis force in the rotating frame. Experimental data are used to quantify the behavior of the minimum Reynolds number for subcritical turbulence as a function of rotation and curvatu

Anthony J. Baltz

Coulomb corrections to perturbation theory for producing electron-positron pairs in ultrarelativistic heavy ion collisions are considered in a part-analytical, part-numerical approach. Production probabilities are reduced from perturbation theory with increasing charge of the colliding heavy ions, as has been previously argued in the literature. It is shown

Wen-Jun Guo, Huan-Qing Jiang, Jian-Ye Liu, Wei Zuo

We develop the method for the calculation of the total reaction cross sections induced by the halo nuclei and stable nuclei. This approach is based on the Glauber theory, which is valid for nuclear reactions at high energy. It is extended for nuclear reactions at low energy and intermediate energy by including both the quantum correction and Coulomb correcti

E. J. Stephenson, A. D. Bacher, C. E. Allgower, A. Gardestig

We report the first observation of the charge symmetry breaking d + d -> 4He + pi0 reaction near threshold at the Indiana University Cyclotron Facility. Kinematic reconstruction permitted the separation of 4He + pi0 events from double radiative capture 4He + gamma + gamma events. We measured total cross sections for neutron pion production of 12.7 +- 2.2 pb

Luca Salasnich

Recently we have derived an effective one-dimensional nonpolynomial Schrödinger equation (NPSE) [Phys. Rev. A {\bf 65}, 043614 (2002)] that accurately describes atomic Bose-Einstein condensates under transverse harmonic confinement. In this paper we analyze the stability of the solitary-wave solutions of NPSE by means of the Vakhitov-Kolokolov criterion. Sta

Benji N. Fisher, David A. Rabson

In 1962, Bienenstock and Ewald described the classification of crystalline space groups algebraically in the dual, or Fourier, space. Recently, the method has been applied to quasicrystals and modulated crystals. This paper phrases Bienenstock and Ewald's definitions in terms of group cohomology. A \textit{Fourier quasicrystal} is defined, along with its

James M. Belk, Kenneth S. Brown

We introduce forest diagrams to represent elements of Thompson's group F. These diagrams relate to a certain action of F on the real line in the same way that tree diagrams relate to the standard action of F on the unit interval. Using forest diagrams, we give a conceptually simple length formula for elements of F with respect to the {x_0,x_1} generating

Mark W. Meckes

We consider moments of the normalized volume of a symmetric or nonsymmetric random polytope in a fixed symmetric convex body. We investigate for which bodies these moments are extremized, and calculate exact values in some of the extreme cases. We show that these moments are maximized among planar convex bodies by parallelograms.

Mark W. Meckes

We consider the moments of the volume of the symmetric convex hull of independent random points in an $n$-dimensional symmetric convex body. We calculate explicitly the second and fourth moments for $n$ points when the given body is $B_q^n$ (and all of the moments for the case $q = 2$), and derive from these the asymptotic behavior of the expected volume of

Alexander Givental

The purpose of the notes is to reiterate and expand the viewpoint, outlined in the paper math.AG/0110142 of T. Coates and the author, which recasts the concept of Frobenius manifold in terms of linear symplectic geometry and exposes the role of the twisted loop group L^{(2)}GL_N of hidden symmetries. New applications include a several line proof of the genus

Stefan Friedl

We find full invariants for detecting non--zero elements in ${L}_0(F(t))\otimes \Q$, this group plays an important role in topology in the work done by Casson and Gordon.

Matthias Beck

We obtain a new motivated proof of the reciprocity law for Dedekind sums by computing the constant coefficient of the Ehrhart polynomial for a rectangular triangle in two ways. On the one hand, the constant term is the Euler characteristic, and on the other hand it is given by a cotangent Laurent expansion.

Stefan Friedl

Cochran, Orr and Teichner introduced $L^2$--eta--invariants to detect highly non--trivial examples of non slice knots. Using a recent theorem by Lück and Schick we show that their metabelian $L^2$--eta--invariants can be viewed as the limit of finite dimensional unitary representations. We recall a ribbon obstruction theorem proved by the author using finite

James B. Martin

We consider a branching random walk with binary state space and index set $T^k$, the infinite rooted tree in which each node has k children (also known as the model of "broadcasting on a tree"). The root of the tree takes a random value 0 or 1, and then each node passes a value independently to each of its children according to a 2x2 transition matri

C. Landim, R. M. Sued, G. Valle

We consider the asymmetric exclusion process. We start from a profile which is constant along the drift direction and prove that the density profile, under a diffusive rescaling of time, converges to the solution of a parabolic equation.

Lars Aagaard

Dykema and Haagerup introduced the class of DT-operators and also showed that every DT-operator generate the von Neumann algebra generated by the free group on two generators. In this paper we prove that Voiculescu's non-microstates free entropy dimension is 2 for all DT-operators.

Joerg Winkelmann

We investigate conditions under which a two-dimensional complex semi-torus splits into a direct product of C^* and a one-dimensional compact complex torus.

Amitai Regev, Yuval Roichman

Natural q analogues of classical statistics on the symmetric groups $S_n$ are introduced; parameters like: the q-length, the q-inversion number, the q-descent number and the q-major index. MacMahon's theorem about the equi-distribution of the inversion number and the reverse major index is generalized to all positive integers q. It is also shown that the

P. C. Matthews

Bifurcation with symmetry is considered in the case of an isotropy subgroup with a two-dimensional fixed point subspace and non-zero quadratic terms. In general, there are one or three branches of solutions, and five qualitatively different phase portraits, provided that two non-degeneracy conditions are satisfied. Conditions are also derived to determine wh

S. Kanmani, V. Kannan

It is shown that Devaney Chaotic systems have plenty of large periodic points.

Kyeonghoon Jeong, Seok-Jin Kang, Masaki Kashiwara

In this paper, we develop the crystal basis theory for quantum generalized Kac-Moody algebras. For a quantum generalized Kac-Moody algebra $U_q(\mathfrak g)$, we first introduce the category $\mathcal O_{int}$ of $U_q(\mathfrak g)$-modules and prove its semisimplicity. Next, we define the notion of crystal bases for $U_q(\mathfrak g)$-modules in the category

Irina Katkovskaya, Veniamin Krotov

The boundary behaviour of convolutions with Poisson kernel and with square root from Poisson kernel is essentially differs. The first ones have only nontangential limit. For the last ones the convergence is over domains admittings a logarithmic order of the contact with the boundary . This result was generalized by authors on the spaces of homogeneous type.

Nathanial P. Brown

We give an elementary C*-algebraic proof of a result of Sorin Popa which is of fundamental importance to Elliott's Classification Program.

Jean-Louis Colliot-Thelene, David A. Madore

For each integer d=2,3,4, there exists a field F with cohomological dimension 1 and a del Pezzo surface of degree d over F having no rational point. Proofs use the theorem of Merkur'ev and Suslin, the Riemann-Roch theorem on a surface and Rost's degree formula. ----- Pour chaque entier d=2,3,4, il existe un corps F de dimension cohomologique 1 et une

Makoto Katori, Taro Nagao, Hideki Tanemura

Non-colliding Brownian particles in one dimension is studied. $N$ Brownian particles start from the origin at time 0 and then they do not collide with each other until finite time $T$. We derive the determinantal expressions for the multitime correlation functions using the self-dual quaternion matrices. We consider the scaling limit of the infinite particle

Alexander Givental

According to a conjecture of E. Witten proved by M. Kontsevich, a certain generating function for intersection indices on the Deligne -- Mumford moduli spaces of Riemann surfaces coincides with a certain tau-function of the KdV hierarchy. The generating function is naturally generalized under the name the {\em total descendent potential} in the theory of Gro