October 2002 arXiv papers — page 11

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

We calculate the fluctuation of the energy of a system in Tsallis statistics following the finite heat bath canonical ensemble approach. We obtain this fluctuation as the second derivative of the logarithm of the partition function plus an additional term. We also find an explicit expression for the relative fluctuation as related to the number of degrees of

J. Bellissard, J. Magnen, V. Rivasseau

This work proposes a very simple random matrix model, the Flip Matrix Model, liable to approximate the behavior of a two dimensional electron in a weak random potential. Its construction is based on a phase space analysis, a suitable discretization and a simplification of the true model. The density of states of this model is investigated using the supersymm

Roberto Benzi, Itamar Procaccia

Direct Numerical Simulations established that the FENE-P model of viscoelastic flows exhibits the phenomenon of turbulent drag reduction which is caused in experiments by dilute polymeric additives. To gain analytic understanding of the phenomenon we introduce in this Letter a simple 1-dimensional model of the FENE-P equations. We demonstrate drag reduction

S. -L. Drechsler, H. Rosner, G. Paasch, J. Malek

We consider electronic structure and superconductivity aspects in field-doped polyacenes (PA) and C60. Within a modified Thomas-Fermi approach for typical experimental values of the surface charge density the injected charge is confined to a monolayer. The electron-phonon coupling constant for internal modes is estimated using the work of Devos et al. (Phys.

A. M. Dyugaev, P. D. Grigoriev, P. Wyder

Charged clusters in liquid helium in an external electric field form a two-dimensional system below the helium surface. This 2D system undergoes a phase transition from a liquid to a Wigner crystal at rather high temperatures. Contrary to the electron Wigner crystal, the Wigner lattice of charged clusters can be detected directly.

P. Karmakar, D. Ghose

A 30 nm Pt thin film evaporated onto a Si wafer was sputtered by 8 keV Ar$^{+}$ ions at various ion doses. The evolution of the modified sputtered films was monitored by atomic force microscopy (AFM), high resolution scanning electron microscopy (HRSEM) and Rutherford backscattering spectrometry (RBS). The most interesting observation was the formation of mo

H. Guillou, A. D. Kent, G. W. Stupian, M. S. Leung

The Hall response function of symmetric and asymmetric planar Hall effect devices is investigated by scanning a magnetized tip above a sensor surface while simultaneously recording the topography and the Hall voltage. Hall sensor geometries are tailored using a Focused Ion Beam, in standard symmetric and new asymmetric geometries. With this technique we are

R. Hlubina

In the tunnel limit, the current-phase relation of Josephson junctions can be expanded as $I(ϕ)=I_1\sinϕ+I_2\sin 2ϕ$. Standard BCS theory predicts that $I_1R_N\simΔ/e$ and $I_2/I_1\sim D$, where $R_N$ is the resistance of the junction in the normal state, $Δ$ is the superconducting gap, and $D\ll 1$ is the junction transparency. In the cuprates, the experime

Jaume Masoliver, Miquel Montero, George H. Weiss

We apply the formalism of the continuous time random walk to the study of financial data. The entire distribution of prices can be obtained once two auxiliary densities are known. These are the probability densities for the pausing time between successive jumps and the corresponding probability density for the magnitude of a jump. We have applied the formali

I. P. McCulloch, M. Gulacsi

Dukelsky, Martín-Delgado, Nishino and Sierra (Europhys. Lett., 43, 457 (1998) - hereafter referred to as DMNS) investigated the matrix product method (MPM), comparing it with the infinite-size density matrix renormalization group (DMRG). For equivalent basis size, the MPM produces an improved variational energy over that produced by DMRG and, unlike DMRG, pr

M. Thorwart, M. Grifoni, G. Cuniberti, H. W. Ch. Postma

We investigate correlated electronic transport in single-walled carbon nanotubes with two intramolecular tunneling barriers. We suggest that below a characteristic temperature the long range nature of the Coulomb interaction becomes crucial to determine the temperature dependence of the maximum G_max of the conductance peak. Correlated sequential tunneling d

A. V. Rodina, Al. L. Efros, A. Yu. Alekseev

The structure of the electron quantum size levels in spherical nanocrystals is studied in the framework of an eight--band effective mass model at zero and weak magnetic fields. The effect of the nanocrystal surface is modeled through the boundary condition imposed on the envelope wave function at the surface. We show that the spin--orbit splitting of the val

A. Johansen, D. Sornette

We perform an extended analysis of the distribution of drawdowns in the two leading exchange markets (US dollar against the Deutsmark and against the Yen), in the major world stock markets, in the U.S. and Japanese bond market and in the gold market, by introducing the concept of ``coarse-grained drawdowns,'' which allows for a certain degree of fuzz

L. M. Hernandez, Kevin A. Parendo, A. M. Goldman

Measurements of resistance vs. temperature have been carried out on a sequence of quench-condensed ultrathin films of amorphous bismuth (a-Bi). The resistance below about 0.1K was found to be temperature independent in a range of films with thicknesses spanning the superconductor-to-insulator transition that would be inferred by analyzing data obtained above

L. S. Metlov

Kinetics of dislocations is studied by means of computer simulation during intensive plastic deformation. The dynamical effect in the form of soliton-like wave of sharply disrupted interparticle bonds is observed. Along with it, micropores similar to steam bubbles at water boiling are formed. After some deformation the solid takes an ideal structure again ow

F. A. Akeroyd, S. I. Campbell, C. M. Moreton-Smith

In this paper we present the new PC-VME based data acquisition system which is now being used on the ISIS Engineering diffractometer instrument, ENGIN-X.

A. J. Silvestre, O. Conde

Results on the chemical composition, structure and growth kinetics of titanium nitride (TiN) films deposited on mild steel substrates by pyrolytic laser-induced chemical vapour deposition (LCVD) are presented. Golden coloured lines of TiN were deposited from a reactive gas mixture of TiCl4, N2 and H2 using a continuous wave TEM00 CO2 laser beam as heat sourc

A. I. D'yachenko, V. Yu. Tarenkov, R. Szymczak, H. Szymczak

We have measured the temperature dependence of gap features revealed by Andreev reflection Delta_s and by tunneling Delta in the ab-plane of optimal and slightly overdoped microcrystals of (BiPb)2Sr2Ca2Cu3O10 (Bi2223) with critical temperature Tc=110-115 K, and Bi2Sr2CaCu2O8 (Bi2212) with Tc=80-84 K. The tunneling conductance of Bi2223-Insulator-Bi2223 junct

B. Hoeneisen

We discuss the future evolution of the universe in the light of recent observations. The apparent luminosity vs. redshift of supernovae favor an accelerating universe. However an Einstein-de Sitter critical universe should not be ruled out yet.

Peter D. Edmonds

Binary stars have long been considered to play a crucial role in globular cluster evolution, and offer the advantages of studying systems at the same, well-determined distances. However, early search attempts were consistently thwarted by crowding (particularly in the optical) and initial detections were limited to small numbers of low-mass X-ray binaries (L

Lynne A. Hillenbrand

A detailed understanding of the physics of star and planet formation requires study of individual objects as well as statistical assessment of global properties and evolutionary trends. Observational investigations of circumstellar material surrounding young stars have matured to the point that both spectral energy distributions sampled over more than four d

C. L. Brogan, W. M. Goss

The unusual supernova remnant candidate G357.7-0.1 and the compact source G357.63-0.06 have been observed with the Very Large Array at 1.4 and 8.3 GHz. The H92$α$ line (8.3 GHz) was detected from the compact source with a surprising velocity of about -210 km/s indicating that this source is an \HII region, is most likely located at the Galactic center, and i

Jean-Pierre De Villiers, John F. Hawley

This paper describes the development and testing of a general relativistic magnetohydrodynamic (GRMHD) code to study ideal MHD in the fixed background of a Kerr black hole. The code is a direct extension of the hydrodynamic code of Hawley, Smarr, and Wilson, and uses Evans and Hawley constrained transport (CT) to evolve the magnetic fields. Two categories of

F. Vignarca, S. Migliari, T. Belloni, D. Psaltis

We investigated the relation between the centroid frequency of the quasi-periodic oscillation observed in the power density spectra of a sample of galactic black-hole candidates with the power-law photon index obtained from spectral fits. Our aim is to avoid inner accretion disk radius determination directly from spectral fits, given the uncertainties of the

Ana Palacios, Suzanne Talon, Corinne Charbonnel, Manuel Forestini

We present a first set of results concerning stellar evolution of rotating low-mass stars. Our models include fully consistent transport of angular momentum and chemicals due to the combined action of rotation induced mixing (according to Maeder & Zahn 1998) and element segregation. The analysis of the effects of local variations of molecular weight due to t

Alaa I. Ibrahim, Jean H. Swank, William Parke

A great deal of evidence has recently been gathered in favor of the picture that Soft Gamma Repeaters and Anomalous X-Ray Pulsars are powered by ultra-strong magnetic fields (B > 10^{14} G; i.e. magnetars). Nevertheless, present determination of the magnetic field in such magnetar candidates has been indirect and model dependent. A key prediction concerning

Jesper Sommer-Larsen, Sune Toft, Jesper Rasmussen, Kristian Pedersen

The X-ray properties of the haloes of disk galaxies formed in fully cosmological, hydro/gravity simulations are discussed. The results are found to be consistent with observational X-ray detections and upper limits. Disk galaxy haloes are predicted to be about an order of magnitude brighter in soft X-rays at z~1 than at z=0. The Ly-alpha and H-alpha surface

Alaa I. Ibrahim, Samar Safi-Harb, Jean H. Swank, William Parke

We report evidence of cyclotron resonance features from the Soft Gamma Repeater SGR 1806-20 in outburst, detected with the Rossi X-ray Timing Explorer in the spectrum of a long, complex precursor that preceded a strong burst. The features consist of a narrow 5.0 keV absorption line with modulation near its second and third harmonics (at 11.2 keV and 17.5 keV

T. K. Gaisser, Todor Stanev

We calculate the intensities and angular distributions of positive and negative muons produced by atmospheric neutrinos. We comment on some sources of uncertainty in the charge ratio. We also draw attention to a potentially interesting signature of neutrino oscillations in the muon charge ratio, and we discuss the prospects for its observation (which are not

P. Wozniak, K. Borozdin, M. Galassi, W. Priedhorsky

The mining of Virtual Observatories (VOs) is becoming a powerful new method for discovery in astronomy. Here we report on the development of SkyDOT (Sky Database for Objects in the Time domain), a new Virtual Observatory, which is dedicated to the study of sky variability. The site will confederate a number of massive variability surveys and enable explorati

Sonia Temporin, Stefano Ciroi

We have identified a new group of galaxies, CG J0247+44.9, at low Galactic latitude (l=143.64 deg, b=-13.29 deg), which satisfies Hickson's criteria (Hickson 1997) for Compact Groups (CGs). Our group consists of six members, two of which are in close interaction (IRAS 02443+4437). We present here optical photometry (BVRI) and low resolution spectroscopy

M. Miyazaki, K. Shimasaku, T. Kodama, S. Okamura

We study the evolution of elliptical galaxies at z >~ 1 on the basis of a sample of 247 Extremely Red Objects (EROs) with R-Ks >= 3.35 (AB) and Ks <= 22.1 (AB) constructed from BVRi&#39;z&#39;JHKs multicolor data of a 114 arcmin2 area in the Subaru/XMM Deep Survey Field. By fitting template spectra of old ellipticals (OEs) and young, dusty starbursts (DSs) t

Tsuyoshi Sakamoto, Masashi Chiba, Timothy C. Beers

We set new limits on the mass of the Milky Way, making use of the latest kinematic information for Galactic satellites and halo objects. In order to bind these sample objects to the Galaxy, their rest-frame velocities must be lower than their escape velocities at their estimated distances. This constraint enables us to show that the mass estimate of the Gala

Atsushi Taruya, Takashi Hamana, Issha Kayo

We present a simple model based on the dark halo approach which provides a useful way to understand key points determining the shape of the non-Gaussian tails of the dark matter one-point probability distribution function(PDF). In particular, using the scale-free models with power-law profile of dark halos, we derive a simple analytic expression for the one-

Peter G. Jonker, Michiel van der Klis, Paul J. Groot

Using phase resolved spectroscopic observations obtained with the Ultraviolet and Visual Echelle Spectrograph on ESO&#39;s Kueyen Very Large Telescope supplemented by spectroscopic observations obtained with the Boller and Chivens Spectrograph on the Walter Baade Magellan telescope, we found sinusoidal radial-velocity variations with a semi-amplitude 327+-17

J. Mikolajewska, E. Brandi, L. Garcia, O. Ferrer

We present and discuss a hundred year history of activity of the hot component of RX Pup based on optical photometry and spectroscopy. The outburst evolution of RX Pup resembles that of other symbiotic novae whereas at quiescence the hot component shows activity (high and low activity states) resembling that of symbiotic recurrent novae T CrB and RS Oph.

A. D. Biggs, D. Rusin, I. W. A. Browne, A. G. de Bruyn

We report the discovery of a new gravitational lens system from the CLASS survey. Radio observations with the VLA, the WSRT and MERLIN show that the radio source B0850+054 is comprised of two compact components with identical spectra, a separation of 0.7 arcsec and a flux density ratio of 6:1. VLBA observations at 5 GHz reveal structures that are consistent

H. R. de Ruiter, P. Parma, A. Capetti, R. Fanti

Almost 60% of the B2 low luminosity radio galaxies have been observed with the Hubble Space Telescope. We present an analysis of the dust features, which are often present in the form of circum-nuclear disks or lanes, and show that there are correlations between radio source and dust properties. It is found that nearby radio sources in which a jet has been d

L. Staveley-Smith, S. Kim, M. R. Calabretta, R. F. Haynes

We present a Parkes multibeam \HI survey of the Large Magellanic Cloud (LMC). This survey, which is sensitive to spatial structure in the range 200 pc to 10 kpc, complements the Australia Telescope Compact survey, which is sensitive to structure in the range 15 pc to 500 pc. With an rms column density sensitivity of 8 x 10^16/cm^2 for narrow lines and 4 x 10

Eniko Regos, Christopher A. Tout, Dayal Wickramasinghe, Jarrod R. Hurley

The progenitors of Type Ia supernovae (SNe Ia) have not been identified. Though they are no longer fashionable we investigate the consequences if a significant number of SNe Ia were edge-lit detonations (ELDs) of carbon/oxygen white dwarfs that have accreted a critical mass of helium. Our best understanding of the Phillips relation between light curve speed

Vittorio Giovannetti, Stefano Mancini, David Vitali, Paolo Tombesi

We derive a separability criterion for bipartite quantum systems which generalizes the already known criteria. It is based on observables having generic commutation relations. We then discuss in detail the relation among these criteria.

G. Policastro, D. T. Son, A. O. Starinets

As a non-trivial check of the non-supersymmetric gauge/gravity duality, we use a near-extremal black brane background to compute the retarded Green&#39;s functions of the stress-energy tensor in N=4 super-Yang-Mills (SYM) theory at finite temperature. For the long-distance, low-frequency modes of the diagonal components of the stress-energy tensor, hydrodyna

Emil A. Yuzbashyan, William Happer, Boris L. Altshuler, B. Sriram Shastry

In this paper we revisit the problem of finding hidden symmetries in quantum mechanical systems. Our interest in this problem was renewed by nontrivial degeneracies of a simple spin Hamiltonian used to model spin relaxation in alkali-metal vapors. We consider this spin Hamiltonian in detail and use this example to outline a general approach to finding symmet

Kristen Menou, James Y-K. Cho, Sara Seager, Brad Hansen

Shallow-water numerical simulations show that the atmospheric circulation of the close-in extrasolar giant planet (EGP) HD 209458b is characterized by moving circumpolar vortices and few bands/jets (in contrast with ~10 bands/jets and absence of polar vortices on cloud-top Jupiter and Saturn). The large spatial scales of moving circulation structures on HD 2

Gábor Lukács

A topological group $G$ is {\em sequentially $h$-complete} if all the continuous homomorphic images of $G$ are sequentially complete. In this paper we give necessary and sufficient conditions on a complete group for being compact, using the language of sequential $h$-completeness. In the process of obtaining such conditions, we establish a structure theorem

Olaf Müller

In this note a proof is given for global existence and uniqueness of minimal surfaces of Lorentzian type from a cylinder into globally hyperbolic Lorentzian manifolds for given initial values up to the first derivatives.

Adam N. Davis, Dragan Huterer, Lawrence M. Krauss

We use the statistics of strong gravitational lensing from the CLASS survey to impose constraints on the velocity dispersion and density profile of elliptical galaxies. This approach differs from much recent work, where the luminosity function, velocity dispersion and density profile were typically {\it assumed} in order to constrain cosmological parameters.

Arjun Berera, Rudnei O. Ramos

A dissipative mechanism is presented, which emerges in generic interacting quantum field systems and which leads to robust warm inflation. An explicit example is considered, where using typical parameter values, it is shown that considerable radiation can be produced during inflation. The extension of our results to expanding spacetime also is discussed.

Vahagn Nazaryan

Carlson, Carone and Lebed have derived the Feynman rules for a consistent formulation of noncommutative QCD. The results they obtained were used to constrain the noncommutativity parameter in Lorentz violating noncommutative field theories. However, their constraint depended upon an estimate of the matrix element of the quark level operator (gamma.p - m) in

Scott A. Hughes

The LIGO (Laser Interferometer Gravitational-Wave Observatory) detectors have just completed their first science run, following many years of planning, research, and development. LIGO is a member of what will be a worldwide network of gravitational-wave observatories, with other members in Europe, Japan, and -- hopefully -- Australia. Plans are rapidly matur

O. Zubelevich

We prove that the evolutionary Navier-Stokes equation in n-D torus with initial data in the class of distributions has an unique solution (local in t) that is analytic by all variables. This solution presents as a series globally.

N. Fusco, M. Zannetti

The problem of the equivalence of the spherical and mean spherical models, which has been thoroughly studied and understood in equilibrium, is considered anew from the dynamical point of view during the time evolution following a quench from above to below the critical temperature. It is found that there exists a crossover time $t^* \sim V^{2/d}$ such that f

Sean A. Hartnoll, Carlos Nunez

We show that the $E-S \sim \log S$ behaviour found for long strings rotating on $AdS_5\times S^5$ may be reproduced by membranes rotating on $AdS_4\times S^7$ and on a warped $AdS_5$ M-theory solution. We go on to obtain rotating membrane configurations with the same $E-K \sim \log K$ relation on $G_2$ holonomy backgrounds that are dual to ${\mathcal{N}}=1$

D. Bailin, G. V. Kraniotis, A. Love

We construct intersecting D5-brane orbifold models that yield the (non-supersymmetric) standard model up to vector-like matter and charged-singlet scalars. The models are constrained by the requirement that twisted tadpoles cancel, and that the gauge boson coupled to the weak hypercharge $U(1)_Y$ does not get a string-scale mass via a generalised Green-Schwa

Frank C. van den Bosch, Xiaohu Yang, H. J. Mo

(Abridged) Using data from the 2dFGRS we compute the conditional luminosity functions (CLFs) of early- and late-type galaxies. These functions give the average number of galaxies with luminosity L that reside in a halo of mass M, and are a powerful statistical tool to link the distribution of galaxies to that of dark matter haloes. We find that the average m

E. Fiorani, G. Giachetta, G. Sardanashvily

Under ceratin conditions, generalized action-angle coordinates can be introduced near non-compact invariant manifolds of completely and partially integrable Hamiltonian systems.

Florian Conrady, Christoph Schweigert

We analyze and compare two families of topologies that have been proposed for representation spaces of chiral algebras by Huang and Gaberdiel & Goddard respectively. We show, in particular, that for suitable pairs the topology of Gaberdiel & Goddard is coarser. We also give a new proof that the chiral two-point blocks are continuous in the topology of Huang.

N. Ya. Ivanov, P. E. Bosted, K. Griffioen, S. E. Rock

We analyze the possibility of measuring the single spin asymmetry (SSA) in open charm production by linearly polarized photons in the planned E160/E161 experiments at SLAC using the inclusive spectra of secondary (decay) leptons. In leading order pQCD, the SSA in the azimuthal distribution of the charged decay lepton is predicted to be about 0.2 for SLAC kin

S. E. Derkachov, G. P. Korchemsky, A. N. Manashov

We construct representation of the Separated Variables (SoV) for the quantum SL(2,R) Heisenberg closed spin chain and obtain the integral representation for the eigenfunctions of the model. We calculate explicitly the Sklyanin measure defining the scalar product in the SoV representation and demonstrate that the language of Feynman diagrams is extremely usef

C. Ratti

The stability of strange quark matter is studied within the Nambu Jona-Lasinio model with three different parameter sets. The model Lagrangian contains 4-fermion (with and without vector interaction) and 6-fermion terms; the minimum energy per baryon number as a function of the strangeness fraction of the system is compared to the masses of hyperons having t

T. V. Dudnikova, A. I. Komech, H. Spohn

We consider the dynamics of a harmonic crystal in $d$ dimensions with $n$ components, $d,n$ arbitrary, $d,n\ge 1$, and study the distribution $μ_t$ of the solution at time $t\in\R$. The initial measure $μ_0$ has a translation-invariant correlation matrix, zero mean, and finite mean energy density. It also satisfies a Rosenblatt- resp. Ibragimov-Linnik type m

Matthieu Wyart, Jean-Philippe Bouchaud

We study Sutton&#39;s `microcanonical&#39; model for the internal organisation of firms, that leads to non trivial scaling properties for the statistics of growth rates. We show that the growth rates are asymptotically Gaussian in this model, at variance with empirical results. We also obtain the conditional distribution of the number and size of sub-sectors

Aleksandar Ivić

Asymptotic formulas for $\sum_{κ_j\le K}α_j H_j^k(1/2)$ are proved when $k = 3,4$, where $H_j(s)$ is the Hecke series.

Atish Dabholkar, Chris Hull

We investigate compactifications with duality twists and their relation to orbifolds and compactifications with fluxes. Inequivalent compactifications are classified by conjugacy classes of the U-duality group and result in gauged supergravities in lower dimensions with nontrivial Scherk-Schwarz potentials on the moduli space. For certain twists, this mechan

Rong-Gen Cai, Jian-Xin Lu, Nobuyoshi Ohta

We study noncommutative open string (NCOS) theories realized in string theory with time-dependent backgrounds. Starting from a noncommutative Yang-Mills theory (NCYM) with a constant space-space noncommutativity but in a time-dependent background and making an S-dual transformation, we show that the resulting theory is an NCOS also in a time-dependent backgr

T. Kurimoto, Hsiang-nan Li, A. I. Sanda

We calculate the $B\to D^{(*)}$ form factors in the heavy-quark and large-recoil limits in the perturbative QCD framework based on $k_T$ factorization theorem, assuming the hierachy $M_B\gg M_{D^{(*)}}\gg \barΛ$, with the $B$ meson mass $M_B$, the $D^{(*)}$ meson mass $M_{D^{(*)}}$, and the heavy meson and heavy quark mass difference $\barΛ$. The qualitative

M. Hirata, N. Katagiri, T. Takaki

Effects of non-resonant photoproductions arising from two different $πNN$ couplings are investigated in the $γN\toππN$ reaction. We find that the pseudoscalar (PS) $πNN$ coupling is generally preferable to the pseudovector (PV) $πNN$ coupling and particularly the total cross sections are successfully described by the model with the PS $πNN$ coupling. In orde

L. Stodolsky, Pierre van Baal, V. I. Zakharov

It is shown how in principle for non-abelian gauge theories it is possible in the finite volume hamiltonian framework to make sense of calculating the expectation value of ||A||^2=\int d^3x(A^a_i(x))^2. Gauge invariance requires one to replace ||A||^2 by its minimum over the gauge orbit, which makes it a highly non-local quantity. We comment on the difficult

I. V. Moskalenko, A. W. Strong, S. G. Mashnik, J. F. Ormes

Recent measurements of the cosmic ray (CR) antiproton flux have been shown to challenge existing CR propagation models. It was shown that the reacceleration models designed to match secondary to primary nuclei ratios (e.g., boron/carbon) produce too few antiprotons. Matching both the secondary to primary nuclei ratio and the antiproton flux requires artifici

Claus Kiefer

A central feature in the Copenhagen interpretation is the use of classical concepts from the outset. Modern developments show, however, that the emergence of classical properties can be understood within the framework of quantum theory itself, through the process of decoherence. This fact becomes most crucial for the interpretability of quantum cosmology - t

V. V. Belokurov, O. A. Khrustalev, V. A. Sadovnichy, O. D. Timofeevskaya

A new quantum mechanical notion -- Conditional Density Matrix -- is discussed and is applied to describe some physical processes. This notion is a natural generalization of von Neumann density matrix for such processes as divisions of quantum systems into subsystems and reunifications of subsystems into new joint systems. Conditional Density Matrix assigns a

V. N. Gorbachev, A. I. Zhiliba, A. I. Trubilko

A master equation for light generated by atoms, which states are prepared by a pumping mechanism that produces atomic correlations, is derived in the Fokker-Planck approximation. It has been found that two-particle correlations only play the role under this approach. Then the equation is applied for describing micromaser operations and light noise is discuss

C. E. Aguiar, F. Laudares

We show that a well known method for measuring the coefficient of restitution of a bouncing ball can also be used to obtain the gravitational acceleration.

Karl Svozil

In this speculative note some of the conceivable options of supercavitation in the vacuum of quantized field theory are discussed. The resulting modes of propagation could in principle be faster than the velocity of light in unbounded space-time.

Spiros Skourtis, Abraham Nitzan

The dependence of electron transfer rates and yields in bridged molecular systems on the bridge length, and the dependence of the zero-bias conduction of molecular wires on wire length are discussed. Both phenomena are controlled by tunneling across the molecular bridge and are consequently expected to show exponential decrease with bridge length that is ind

Andrew E. Chubykalo, Rolando Alvarado Flores

In this brief note we critically examine the process of partial and of total differentiation, showing some of the problems that arise when we relate both concepts. A way to solve all the problems is proposed.

Yuichi Togashi, Kunihiko Kaneko

We study an autocatalytic system consisting of several interacting chemical species. We observe a strong dependence of the concentrations of the chemicals on the size of the system. This dependence is caused by the discrete nature of the molecular concentrations. Two basic mechanisms responsible for them are identified and elucidated. The relevance of the tr

R. A. Gherghescu

A highly specialized two-center shell model has been developed accounting for the splitting of a deformed parent nucleus into two ellipsoidaly deformed fragments. The potential is based on deformed oscillator wells in direct correspondance with the shape change of the nuclear system. For the first time a potential responsible for the necking part between the

Harald A. Posch, William G. Hoover

Thermostated tethered harmonic lattices provide good illustrations of the phase-space dimensionality loss which occurs in the strange-attractor distributions characterizing stationary nonequilibrium flows. We use time-reversible nonequilibrium molecular dynamics, with two Nose-Hoover thermostats, one hot and one cold, to study a family of square heat-conduct

Srihari Keshavamurthy

In this letter we study dynamical tunneling in highly excited symmetric molecules. The role of classical phase space structures like resonances and chaos on the tunneling splittings are illustrated using the water molecule as an example. It is argued that the enhancements in the splittings due to resonances (near-integrable phase space) and due to chaos (mix

A. H. Vartanian

For Lax-pair isospectral deformations whose associated spectrum, for given initial data, consists of the disjoint union of a finitely denumerable discrete spectrum (solitons) and a continuous spectrum (continuum), the matrix Riemann-Hilbert problem approach is used to derive the leading-order asymptotics as $| t | \to \infty$ $(x/t \sim \mathcal{O} (1))$ of

Manuel Blickle

In this paper I show that, just as in the smooth case, the Cartier operator induces an isomorphism on the Zariski-deRham complex of any toric variety.

Ralph L. Cohen, John D. S Jones, Jun Yan

Chas and Sullivan recently defined an intersection product on the homology $H_*(LM)$ of the space of smooth loops in a closed, oriented manifold $M$. In this paper we will use the homotopy theoretic realization of this product described by the first two authors to construct a second quadrant spectral sequence of algebras converging to the loop homology multi

Ralph L. Cohen, Andrew Stacey

In this paper we investigate bundles whose structure group is the loop group LU(n). Our main result is to give a necessary and sufficient criterion for there to exist a Fourier type decomposition of such a bundle $ξ$. This is essentially a decomposition of $ξ$ as $ζ\otimes L\mathbb C$, where $ζ$ is a finite dimensional subbundle of $ξ$ and $L\mathbb C$ is th

Raf Cluckers

We study Grothendieck rings (in the sense of logic) of fields. We prove the triviality of the Grothendieck rings of certain fields by constructing definable bijections which imply the triviality. More precisely, we consider valued fields, for example, fields of Laurent series over the real numbers, over p-adic numbers and over finite fields, and construct de

V. Beresnevich, V. Bernik, D. Kleinbock, G. A. Margulis

The main objective of this paper is to prove a Khintchine type theorem for divergence for linear Diophantine approximation on non-degenerate manifolds, which completes earlier results for convergence.

Cinzia Casagrande

We give a structure theorem for n-dimensional smooth toric Fano varieties whose associated polytope has &#34;many&#34; pairs of centrally symmetric vertices.

Ai-Hua Fan, Benoit Saussol, Joerg Schmeling

Let $β>1$ be a real number and $M: \mathbb{R}\to {\rm GL(\CC^d)}$ be a uniformly almost periodic matrix-valued function. We study the asymptotic behavior of the product $$ P_n(x) =M(β^{n-1}x)... M(βx) M(x). $$ Under some condition we prove a theorem of Furstenberg-Kesten type for such products of non-stationary random matrices. Theorems of Kingman and Oseled

Roderik Lindenbergh

In this thesis we study sets of points in the plane and their Voronoi diagrams, in particular when the points coincide. We bring together two ways of studying point sets that have received a lot of attention in recent years: Voronoi diagrams and compactifications of configuration spaces. We study moving and colliding points and this enables us to introduce `

Frederic Le Roux

The study of the dynamics of a surface homeomorphism in the neighbourhood of an isolated fixed point leads us to the following results. If the fixed point index is greater than 1, a family of attractive and repulsive petals is constructed, generalizing the Leau-Fatou flower theorem in complex dynamics. If the index is less than 1, we get a family of stable a

I. G. Korepanov, E. V. Martyushev

We construct new topological invariants of three-dimensional manifolds which can, in particular, distinguish homotopy equivalent lens spaces L(7,1) and L(7,2). The invariants are built on the base of a classical (not quantum) solution of pentagon equation, i.e.algebraic relation corresponding to a ``2 tetrahedra to 3 tetrahedra&#39;&#39; local re-building of

Pavel Grigoriev

This paper contains some estimates for the {\it integral-uniform} norm and the uniform norm of a wide class of random polynomials. The family of integral-uniform norms introduced by Kasin and Tzafriri is a natural generalization of the maximum norm taken over a net. We prove some properties of the integral-uniform norms. The given application of the establis

Pavel Grigoriev

In the paper I study properties of random polynomials with respect to a general system of functions. Some lower bounds for the mathematical expectation of the uniform and recently introduced integral-uniform norms of random polynomials are established. {\sc Key words and phrases:} Random polynomial, estimates for maximum of random process, integral-uniform n

H. -D. Doebner, T. D. Palev, N. I. Stoilova

It is shown that the Clifford superalgebra Cl(n|m) generated by m pairs of Bose operators (odd elements) anticommuting with n pairs of Fermi operators (even elements) can be deformed to Cl_q(n|m) such that the latter is a homomorphic image of the quantum superalgebra U_q[osp(2n+1|2m)]. The Fock space F(n|m) of Cl_q(n|m) is constructed. At q being a root of u

Raphael Yuster

Let $F=\{H_1,...,H_k\}$ be a family of graphs. A graph $G$ with $m$ edges is called {\em totally $F$-decomposable} if for {\em every} linear combination of the form $α_1 e(H_1) + ... + α_k e(H_k) = m$ where each $α_i$ is a nonnegative integer, there is a coloring of the edges of $G$ with $α_1+...+α_k$ colors such that exactly $α_i$ color classes induce each

Raphael Yuster

Let $TT_k$ denote the transitive tournament on $k$ vertices. Let $TT(h,k)$ denote the graph obtained from $TT_k$ by replacing each vertex with an independent set of size $h \geq 1$. The following result is proved: Let $c_2=1/2$, $c_3=5/6$ and $c_k=1-2^{-k-\log k}$ for $k \geq 4$. For every $ε> 0$ there exists $N=N(ε,h,k)$ such that for every undirected graph

Jean Bourgain, Wei-Min Wang

We prove that at large disorder, with large probability and for a set of Diophantine frequencies of large measure, Anderson localization in $\Bbb Z^d$ is {\it stable} under localized time-quasi-periodic perturbations by proving that the associated quasi-energy operator has pure point spectrum. The main tools are the Fröhlich-Spencer mechanism for the random

Kyeonghee Jo, Hyuk Kim

In this paper, we show that the Euler characteristic of an even dimensional closed projectively flat manifold is equal to the total measure which is induced from a probability Borel measure on RP^n invariant under the holonomy action, and then discuss its consequences and applications. As an application, we show that the Chern&#39;s conjecture is true for a

Alexander Gnedin

Sampling formulas describe probability laws of exchangeable combinatorial structures like partitions and compositions. We give a brief account of two known parametric families of sampling formulas and add a new family to the list.

Leovigildo Alonso, Ana Jeremias, Ma. -Jose Souto

We associate a t-structure to a family of objects in D(A), the derived category of a Grothendieck category A. Using general results on t-structures, we give a new proof of Rickard&#39;s theorem on equivalence of bounded derived categories of modules. Also, we extend this result to bounded derived categories of quasi-coherent sheaves on separated divisorial s