April 1999 arXiv papers — page 8

Antonina N. Fedorova, Michael G. Zeitlin

In this series of eight papers we present the applications of methods from wavelet analysis to polynomial approximations for a number of accelerator physics problems. In this part we consider application of FWT to metaplectic representation(quantum and chaotical problems) and quasiclassics.

J Paret, M. C. Jullien, P Tabeling

We report the first extensive experimental observation of the two-dimensional enstrophy cascade, along with the determination of the high order vorticity statistics. The energy spectra we obtain are remarkably close to the Kraichnan Batchelor expectation. The distributions of the vorticity increments, in the inertial range, deviate only little from gaussiani

Antonina N. Fedorova, Michael G. Zeitlin

In this series of eight papers we present the applications of methods from wavelet analysis to polynomial approximations for a number of accelerator physics problems. In this part we consider the applications of discrete wavelet analysis technique to maps which come from discretization of continuous nonlinear polynomial problems in accelerator physics. Our m

Antonina N. Fedorova, Michael G. Zeitlin

In this series of eight papers we present the applications of methods from wavelet analysis to polynomial approximations for a number of accelerator physics problems. In this part we consider a model for spin-orbital motion: orbital dynamics and Thomas-BMT equations for classical spin vector. We represent the solution of this dynamical system in framework of

Antonina N. Fedorova, Michael G. Zeitlin

In this series of eight papers we present the applications of methods from wavelet analysis to polynomial approximations for a number of accelerator physics problems. In this part, assuming a sinusoidal field variation, we consider the analytical treatment of the effects of insertion devices on beam dynamics. We investigate via wavelet approach a dynamical m

Antonina N. Fedorova, Michael G. Zeitlin

In this series of eight papers we present the applications of methods from wavelet analysis to polynomial approximations for a number of accelerator physics problems. In this part we consider orbital motion in transverse plane for a single particle in a circular magnetic lattice in case when we take into account multipolar expansion up to an arbitrary finite

Antonina N. Fedorova, Michael G. Zeitlin

In this series of eight papers we present the applications of methods from wavelet analysis to polynomial approximations for a number of accelerator physics problems. In this part, according to variational approach we obtain a representation for orbital particle motion in storage rings as a multiresolution (multiscales) expansion in the base of well-localize

A. E. L. Dieperink, S. I. Nagorny

Exclusive photodisintegration of the deuteron in the 1-4GeV range is described in terms of a simple covariant and gauge invariant approach using an effective counting rule as the hard part of the d-np vertex. At a scattering angle of theta_cm=90 degrees a prescaling behavior of the differential cross section proportional to 1/s^(n-2) with n ~ 12 is obtained;

Y. G. Ma, Q. M. Su, W. Q. Shen, J. S. Wang

Thermodynamical features of Xe system is investigated as functions of temperature and freeze-out density in the frame of lattice gas model. The calculation shows different temperature dependence of physical observables at different freeze-out density. In this case, the critical temperature when the phase transition takes place depends on the freeze-out densi

Yu-Gang Ma, Qian-Min Su, Wen-Qing Shen, Jian-Song Wang

Isospin effects of the critical phenomena were studied via Xe isotopes in the frame of lattice gas model. All the critical temperatures for four Xe isotopes are close to 5.5 MeV at the same freeze-out density of about 0.39 $ρ_0$. The critical values of power law parameter of mass distribution, mean multiplicity of intermediate mass fragments (IMF), informati

K. Saito, K. Tsushima, A. W. Thomas

Using the quark-meson coupling (QMC) model, we study the longitudinal response function for quasielastic electron scattering from nuclear matter. In QMC the coupling constant between the scalar ($\sigma$) meson and the nucleon is expected to decrease with increasing nuclear density, because of the self-consistent modification of the structure of the nucleon.

Pavel Bleher, Bernard Shiffman, Steve Zelditch

We study the limit as $N\to\infty$ of the correlations between simultaneous zeros of random sections of the powers $L^N$ of a positive holomorphic line bundle $L$ over a compact complex manifold $M$, when distances are rescaled so that the average density of zeros is independent of $N$. We show that the limit correlation is independent of the line bundle and

Claude Bardos, Jean Michel Ghidaglia, Spyridon Kamvissis

The purpose of this contribution is to show that some of the basic ideas of turbulence can be addressed in a deterministic setting instead of introducing random realizations of the fluid. Weak limits of oscillating sequences of solutions are considered and along the same line the Wigner transform replaces the Kolmogorov definition of the spectra of turbulenc

Bernhard Lamel

We give an invariant nondegeneracy condition for CR--maps between generic submanifolds in different dimensions and use it to prove a reflection principle for these maps.

Neal J. Fowler

To each discrete product system E of finite-dimensional Hilbert spaces we associate a C*-algebra O_E. When E is the n-dimensional product system over N, O_E is the Cuntz algebra O_n, and the irrational rotation algebras appear as O_E for certain one-dimensional product systems over N^2. We give conditions which ensure that O_E is simple, purely infinite, and

Neal J. Fowler

A Hilbert bimodule is a right Hilbert module X over a C*-algebra A together with a left action of A as adjointable operators on X. We consider families X = {X_s :s\in P} of Hilbert bimodules, indexed by a semigroup P, which are endowed with a multiplication which implements isomorphisms X_s\otimes_A X_t \to X_{st}; such a family is a called a product system.

Izu Vaisman

We show that the Gerstenhaber algebra of the 1-jet Lie algebroid of a Jacobi manifold has a canonical exact generator, and discuss duality between its homology and the Lie algebroid cohomology. We also discuss a new example of a Lie bialgebroid on Poisson manifolds.

Erik Koelink, Jasper V. Stokman

We give a detailed description of the resolution of the identity of a second order $q$-difference operator considered as an unbounded self-adjoint operator on two different Hilbert spaces. The $q$-difference operator and the two choices of Hilbert spaces naturally arise from harmonic analysis on the quantum group $SU_q(1,1)$ and $SU_q(2)$. The spectral analy

Miklós Bóna, Rodica Simion

We introduce two partially ordered sets, $P^A_n$ and $P^B_n$, of the same cardinalities as the type-A and type-B noncrossing partition lattices. The ground sets of $P^A_n$ and $P^B_n$ are subsets of the symmetric and the hyperoctahedral groups, consisting of permutations which avoid certain patterns. The order relation is given by (strict) containment of the

K. Zarembo

The AdS/CFT correspondence predicts a phase transition in Wilson loop correlators in the strong coupling N=4, D=4 SYM theory which arises due to instability of the classical string stretched between the loops. We study this transition in detail by solving equations of motion for the string in the particular case of two circular Wilson loops. The transition i

R. B. Mann

Using a boundary counterterm prescription motivated by the AdS/CFT conjecture, I evaluate the energy, entropy and angular momentum of the class of Kerr-NUT/bolt-AdS spacetimes. As in the non-rotating case, when the NUT charge is nonzero the entropy is no longer equal to one-quarter of the area due to the presence of the Misner string. When the cosmological c

Krzysztof Gawedzki

This is a set of introductory lecture notes devoted to the Wess-Zumino-Witten model of two-dimensional conformal field theory. We review the construction of the exact solution of the model from the functional integral point of view. The boundary version of the theory is also briefly discussed.

M. L. Walker, C. J. Burden

We derive the complete set of supersymmetric Ward identities involving only two- and three- point proper vertices in supersymmetric QED. We also present the most general form of the proper vertices consistent with both the supersymmetric and U(1) gauge Ward identities. These vertices are the supersymmetric equivalent of the non supersymmetric Ball-Chiu verti

F. Antonuccio, J. O. Andersen

We perform a two-loop calculation in light-front phi^4 theory to determine the effective mass renormalization of the light-front Hamiltonian. The renormalization scheme adopted here is manifestly boost invariant, and yields results that are in perfect agreement with the explicitly covariant Feynman diagram approach.

Kaustubh Agashe, Michael Graesser

In a generic supersymmetric extension of the Standard Model, there will be lepton flavor violation at a neutral gaugino vertex due to misalignment between the lepton Yukawa couplings and the slepton soft masses. Sleptons produced at the LHC through the cascade decays of squarks and gluinos can give a sizable number of events with 4 leptons. This channel coul

M. A. Ivanov, J. G. Korner, V. E. Lyubovitskij, A. G. Rusetsky

We analyze strong one-pion and radiative one-photon decays of heavy flavored baryons within a relativistic three-quark model. Employing the same parameters as were used for the description of the semileptonic decays of heavy baryons, we calculate the couplings of one-pion and one-photon transitions of both ground and excited heavy baryon states. We predict t

I. P. Lokhtin

The angular structure of collisional and radiative energy losses of a hard parton jet propagating through the quark-gluon plasma is analyzed. The possibility to observe the energy losses of quark- and gluon-initiated jets in dense QCD-matter (jet quenching) measuring the characteristics of real hadronic jets in ultra-relativistic collisions of nuclei is inve

A. Bartl, H. Eberl, K. Hidaka, S. Kraml

We perform a detailed study of the decays of the heavier tau slepton (stau_2) and tau-sneutrino (snu_tau) in the Minimal Supersymmetric Standard Model (MSSM). We show that the decays into Higgs or gauge bosons, i.e. stau_2 -> stau_1 + (h^0, H^0, A^0 or Z^0), stau_2 -> snu_tau + (H^- or W^-), and snu_tau -> stau_1 + (H^+ or W^+), can be very important due to

Michael Krämer

We have calculated the next-to-leading order perturbative QCD corrections to the photon energy spectrum in radiative Upsilon decays. The higher-order corrections significantly modify the shape of the spectrum, in particular at large photon energies, and thereby reduce the discrepancy between experimental data and previous leading-order predictions. The next-

A. Nicolaidis, G. Tsirigoti, J. Hansson

The dispersion relation of energetic (few TeV) neutrinos traversing a medium is studied. We use the real time formalism of thermal field theory and we include the effects from the propagator of the W gauge boson. We consider then the MSW oscillations for cosmic neutrinos traversing the Earth, adopting for the neutrino parameters values suggested by the LSND

D0 Collaboration, B. Abbott et al

We report on a search for second generation leptoquarks (LQ) produced in $p\bar{p}$ collisions at sqrt{s} = 1.8 TeV using the D0 detector at Fermilab. Second generation leptoquarks are assumed to be produced in pairs and to decay to either μor νand either a strange or a charm quark (q). Limits are placed on σ(p-pbar -> LQ-LQbar -> μν+ jets) as a function of

Kamiokande Collaboration, Y. Hayato, M. Earl

We present results of a search for proton decays, $p \to \barν K^+$, using data from a 33 kton$\cdot$year exposure of the Super-Kamiokande detector. Two decay modes of the kaon, $K^+ \to μ^+ ν_μ$ and $K^+ \to π^+ π^0$, were studied. The data were consistent with the background expected from atmospheric neutrinos; therefore a lower limit on the partial lifeti

Yasusada Nambu, Yoshiyuki Y. Yamaguchi

Using the renormalization group method, we improved the first order solution of the long-wavelength expansion of the Einstein equation. By assuming that the renormalization group transformation has the property of Lie group, we can regularize the secular divergence caused by the spatial gradient terms and absorb it to the background seed metric. The solution

Stephen F. Bush, Victor S. Frost, Joseph B. Evans

There is a trend toward the use of predictive systems in communications networks. At the systems and network management level predictive capabilities are focused on anticipating network faults and performance degradation. Simultaneously, mobile communication networks are being developed with predictive location and tracking mechanisms. The interactions and s

Stephen F. Bush

This paper introduces a novel algorithm, the Active Virtual Network Management Protocol (AVNMP), for predictive network management. It explains how the AVNMP facilitates the management of an active network by allowing future predicted state information within an active network to be available to network management algorithms. This is accomplished by coupling

Yin Zhang

WebScript is a scripting language for processing Web documents. Designed as an extension to Jacl, the Java implementation of Tcl, WebScript allows programmers to manipulate HTML in the same way as Tcl manipulates text strings and GUI elements. This leads to a completely new way of writing the next generation of Web applications. This paper presents the motiv

Xunya Jiang, Qiming Li, C. M. Soukoulis

We address the issue of whether amplification, like absorption, suppresses wave transmission at large gain, as has been claimed in previous studies of wave propagation in active random media. A closer examination reveals that the paradoxical symmetry between absorption and amplification is an artifact of unphysical solutions from the time-independent wave eq

Valery I. Rupasov

We reexamine the Yang-Yang-Takahashi method of deriving the thermodynamic Bethe ansatz equations which describe strongly correlated electron systems of fundamental physical interest, such as the Hubbard, $s-d$ exchange (Kondo) and Anderson models. It is shown that these equations contain some additional terms which may play an important role in the physics o

Marco Fornari, David J. Singh

First principles calculations are used to investigate the band structure and the transport related properties of unfilled and filled 4d skutterudite antimonides. The calculations show that, while RhSb3 and p-type La(Rh,Ru)4Sb12 are unfavorable for thermoelectric application, n-type La(Rh,Ru)4Sb12 is very likely a high figure of merit thermoelectric material

Jorge Iniguez, Alberto Garcia, J. M. Perez-Mato

We present a new scheme for the construction of highly localized lattice Wannier functions. The approach is based on a heuristic criterion for localization and takes the symmetry constraints into account from the start. We compare the local modes thus obtained with those generated by other schemes and find that they also provide a better description of the r

Ewald Schachinger, Jules P. Carbotte

The quasiparticle density of states in a two-dimensional d-wave superconductor depends on the orientation of the in-plane external magnetic field H. This is because. in the region of the gap nodes, the Doppler shift due to the circulating supercurrents around a vortex depend on the direction of H. For a tetragonal system the induced pattern is four-fold symm

Mark A. Miller, David J. Wales

The potential energy surface of an off-lattice model protein is characterized in detail by constructing a disconnectivity graph and by examining the organisation of pathways on the surface. The results clearly reveal the frustration exhibited by this system and explain why it does not fold efficiently to the global potential energy minimum. In contrast, when

A. Torcini, Ch. Dellago, H. A. Posch

In a recent Letter, Barnett, Tajima, Nishihara, Ueshima and Furukawa obtained a theoretical expression for the maximum Lyapunov exponent $λ_1$ of a dilute gas. They conclude that $λ_1$ is proportional to the cube root of the self-diffusion coefficient $D$, independent of the range of the interaction potential. They validate their conjecture with numerical da

J. J. Koonen, H. Buhmann, L. W. Molenkamp

We report direct observations of the scattering potentials in a two-dimensional electron-gas using electron-beam diffaction-experiments. The diffracting objects are local density-fluctuations caused by the spatial and charge-state distribution of the donors in the GaAs-(Al,Ga)As heterostructures. The scatterers can be manipulated externally by sample illumin

Xunya Jiang, C. M. Soukoulis

The transmission (T) and reflection (R) coefficients are studied in periodic systems and random systems with gain. For both the periodic electronic tight-binding model and the periodic classical many-layered model, we obtain numerically and theoretically the dependence of T and R. The critical length of periodic system L[sub c][sup 0], above which T decrease

V. A. Vdovenkov

The adiabatic cristal model is offered. It is shown that springy nuclei oscillations relatively electronic envelops and waves of such oscillations (inherent oscillations and waves) may exist in crystals. The analysis of experimental temperature dependencies of resistivity in semiconductors with electron-vibrational centres has shown that inherent oscillation

P. Mendels, J. Bobroff, G. Collin, H. Alloul

We present SQUID susceptibility data on Zn and Ni substituted YBa_{2}Cu_{3}O_{6+x}. Cross-checks with NMR yield an unprecedented accuracy in the estimate of the magnetic susceptibility associated with the substituants, from the underdoped to the lightly overdoped case. This allows us to determine the Weiss temperature θfor YBCO: its value is very small for a

Niurka R. Quintero, Angel Sanchez, Franz G. Mertens

We study the sine-Gordon kink diffusion at finite temperature in the overdamped limit. By means of a general perturbative approach, we calculate the first- and second-order (in temperature) contributions to the diffusion coefficient. We compare our analytical predictions with numerical simulations. The good agreement allows us to conclude that, up to tempera

G. Goldoni

We calculate the differential cross-section of the direct double photo-ionization of He physisorbed on a polarizable surface. By including the influence of the surface potential in the correlated two-electron final state wavefunction, we show that the differential cross-section carries detailed information on the electronic correlations at the surface. In pa

Hiroaki Kusunose, Yoshio Kuramoto

We show that a Kondo-type model with an orbital degeneracy has a new non-Fermi-liquid fixed point. Near the fixed point the spin degrees of freedom are completely quenched, and the residual charge degrees of freedom lead to the multi-channel Kondo effect. Anomalous behavior appears in electric and thermal properties, but the magnetic susceptibility should sh

F. Bagnoli, M. Bezzi

We introduce a toy model for interacting populations connected by mutations and limited by a shared resource. We study the presence of Eigen's error threshold and mutational meltdown. The phase diagram of the system shows that the extinction of the whole population due to mutational meltdown can occur well before an eventual error threshold transition.

Michel Fioc, Brigitte Rocca-Volmerange

Growth curves of the near-infrared (NIR) magnitude as a function of the aperture have been built and used to derive NIR total magnitudes from aperture data taken from the literature. By cross-correlating with optical and redshift data, absolute magnitudes and optical-to-NIR colors have been computed for some 1000 galaxies of different types. Significant colo

Lev Titarchuk, Vladimir Osherovich

We present a dimensional analysis of two characteristic time scales in the boundary layer where the disk adjusts to the rotating neutron star (NS). The boundary layer is treated as a transition region between the NS surface and the first Keplerian orbit. The radial transport of the angular momentum in this layer is controlled by a viscous force defined by th

D. B. Sanders

Deep surveys at 850microns from Mauna Kea using the SCUBA camera on the JCMT appear to have discovered a substantial population of ultraluminous infrared galaxies (ULIGs: L_ir > 10^{12} L_sun). The cumulative space density of these sources (~10,000 per sq.deg with S_850 > 1mJy) is sufficient to account for nearly all of the extragalactic background light at

Brian D. Fields, Katherine Freese, David S. Graff

We examine the chemical abundance constraints on a population of white dwarfs in the Halo of our Galaxy. We are motivated by microlensing evidence for massive compact halo objects (Machos) in the Galactic Halo, but our work constrains white dwarfs in the Halo regardless of what the Machos are. We focus on the composition of the material that would be ejected

V. I. Savchenko

We solve the quasiclassical problem of tunneling through an external potential barrier in a dense plasma, where the tunneling particles undergo simultaneous collisions with other particles in thermodynamic equilibrium. Under such conditions the spectral density of states available to the particle has a Lorentz shape, rather than the delta function, which lea

Adam Frank, Thomas A. Gardiner, Guy Delemarter, Thibaut Lery

We address the issue of ambipolar diffusion in Herbig-Haro jets. The current consensus holds that these jets are launched and collimated via MHD forces. Observations have, however, shown that the jets can be mildly to weakly ionized. Beginning with a simple model for cylindrical equilibrium between neutral, plasma and magnetic pressures we calculate the char

T. Antoni, J. R. Hoerandel

Using the large hadron calorimeter of the KASCADE experiment, hadronic cores of extensive air showers have been studied. The hadron lateral and energy distributions have been investigated in order to study the reliability of the shower simulation program CORSIKA with respect to particle transport, decays, treatment of low-energy particles, etc. A good descri

P. M. Vreeswijk, T. J. Galama, A. Owens, T. Oosterbroek

We report on X-ray, optical and infrared follow-up observations of GRB 980703. We detect a previously unknown X-ray source in the GRB error box; assuming a power law decline we find for its decay index alpha < -0.91 (3-sigma). We invoke host galaxy extinction to match the observed spectral slope with the slope expected from `fireball&#39; models. We find no

Carl H. Gibson

The Jeans criterion for the minimum self-gravitational condensation scale is extended to include the possibility of condensation on non-acoustic density nuclei at Schwarz scales, where structure formation begins in the plasma epoch at proto-supercluster masses about 10,000 years after the Big Bang, decreasing to galaxy masses at 300,000 years. Then the plasm

Carl H. Gibson

Dark matter appears in two forms as a consequence of the fluid mechanics of self-gravitational condensation. Condensation occurs primarily on non-acoustic nuclei rather than on the acoustic nuclei of the Jeans (1902) criterion, leading to a very different scenario for structure formation. Viscous forces at 10^12 s (30,000 y) after the big bang permit deceler

J. R. Walsh, N. A. Walton, G. H. Jacoby, R. F. Peletier

Low dispersion spectra have been obtained of five planetary nebulae in the elliptical galaxy NGC 5128 (Centaurus-A) from the catalogue of Hui et al. (1993). The planetary nebulae (PN) cover a range of galactocentric radius from 7.9 to 17.7 arcmin (8 to 18Kpc). The spectra display typical emission lines of H I, He I, He II, [O III], [N II] and [S II] and appe

Reynier Peletier

Although evidence is accumulating that abundance ratios in galaxies are often non-solar, they are far from understood. I resume the current evidence for non-solar abundance ratios, supplementing the recent review by Worthey (1998) with some new results. It appears that the Mg/Fe abundance ratio only depends on the mass of the galaxy, not on the formation tim

P. A. Sturrock, J. D. Scargle, G. Walther, M. S. Wheatland

Recent analysis of the Homestake data indicates that the solar neutrino flux contains a periodic variation that may be attributed to rotational modulation occurring deep in the solar interior, either in the tachocline or in the radiative zone. This paper presents an analysis of GALLEX data that yields supporting evidence of this rotational modulation at the

Dominic J. Benford, Pierre Cox, Alain Omont, Thomas G. Phillips

We report observations of a sample of high redshift sources (1.8<z<4.7), mainly radio-quiet quasars, at 350 microns using the SHARC bolometer camera at the Caltech Submillimeter Observatory. Nine sources were detected (>4-sigma) and upper limits were obtained for 11 with 350 micron flux density limits (3-sigma) in the range 30-125mJy. Combining published res

V. Korchagin, E. I. Vorobyov, Y. D. Mayya

Ring waves of star formation, propagating outwardly in the galactic disks, leave chemical abundance gradients in their wakes. We show that the relative [Fe/O] abundance gradients in ring galaxies can be used as a tool for determining the role of the SNIa explosions in their chemical enrichment. We consider two mechanisms which can create outwardly propagatin

Geoffrey W. Marcy, R. Paul Butler, Steven S. Vogt, Debra Fischer

Doppler measurements of two G-type main-sequence stars, HD210277 and HD168443, reveal Keplerian variations that imply the presence of companions with masses (M sin i) of 1.28 and 5.04 M_Jup and orbital periods of 437 d and 58 d, respectively. The orbits have large eccentricities of e=0.45 and e=0.54, respectively. All 9 known extrasolar planet candidates wit

Eelco van Kampen, Raul Jimenez, John A. Peacock

We show that the discrepancy between the Tully-Fisher relation and the luminosity function predicted by most phenomenological galaxy formation models is mainly due to overmerging of galaxy haloes. We have circumvented this overmerging problem, which is inherent in both the Press-Schechter formalism and dissipationless N-body simulations, by including a speci

C. W. Churchill, R. R. Mellon, J. C. Charlton, B. T. Jannuzi

We have examined Faint Object Spectrograph data from the Hubble Space Telescope Archive for CIV 1548,1550 absorption associated with 40 MgII 2796,2803 absorption-selected galaxies at 0.4 < z < 1.4. We report a strong correlation between MgII kinematics, measured in 6 km/s resolution HIRES/Keck spectra, and W_r(1548); this implies a physical connection betwee

Wil van Breugel, Carlos De Breuck, S. A. Stanford, Dan Stern

We report the discovery of the most distant known AGN, the radio galaxy TN J0924-2201 at z = 5.19. The radio source was selected from a new sample of ultra-steep spectrum (USS) sources, has an extreme radio spectral index alpha_365MHz^1.4GHz = -1.63, and is identified at near-IR wavelengths with a very faint, K = 21.3 +- 0.3 object. Spectroscopic observation

Brad K. Gibson, Michelle Buxton, Emanuel Vassiliadis, Maartje N. Sevenster

We have examined the success rates of 19 American, Canadian, Australian, and Dutch graduate programs in producing astronomers. A 20-year baseline was considered (1975-1994), incorporating 897 PhD recipients. The major conclusion from our study is that the fraction of PhD graduates still involved in astronomical research is surprisingly insensitive to the ins

Shiraz Minwalla, Nathan Seiberg

We study $N$ coincident IIA NS5-branes at large $N$ using supergravity. We show that the absorption cross section for gravitons in this background does not vanish at zero string coupling for energies larger than $m_s/\sqrt{N}$ ($m_s$ is the string scale). Using a holographic description of the intrinsic theory of the IIA NS5-branes, we find an expression for

Carl H. Gibson

Kolmogorov&#39;s three universal similarity hypotheses are extrapolated to describe scalar fields like temperature mixed by turbulence. By the analogous Kolmogorov third hypothesis for scalars, temperature dissipation rates chi averaged over lengths r > L_K should be lognormally distributed with intermittency factors I that increase with increasing turbulenc

P. Kumar, Donavan Hall, R. G. Goodrich

We suggest that the transition to superconductivity in a single crystal of Ba_{0.6}K_{0.4}BiO_3 with a T_c = 32K, and having critical fields with anomalous temperature dependencies and vanishing discontinuities in specific heat and magnetic susceptibility, may well be an example of a fourth order (in Ehrenfest&#39;s sense) phase transition. We have derived a

Benjamin C. Bromley, Max Tegmark

Two recent papers have claimed detection of non-Gaussian features in the COBE DMR sky maps of the cosmic microwave background. We confirm these results, but argue that Gaussianity is still not convincingly ruled out. Since a score of non-Gaussianity tests have now been published, one might expect some mildly significant results even by chance. Moreover, in t

A. Alan Middleton

The effect of open boundary conditions for four models with quenched disorder are studied in finite samples by numerical ground state calculations. Extrapolation to the infinite volume limit indicates that the configurations in ``windows&#39;&#39; of fixed size converge to a unique configuration, up to global symmetries. The scaling of this convergence is co

Julien Lesgourgues, Sergio Pastor

We consider some consequences of the presence of a cosmological lepton asymmetry in the form of neutrinos. Relic neutrino degeneracy enhances the contribution of massive neutrinos to the present energy density of the Universe, and modifies the power spectrum of radiation and matter. Comparing with current observations of cosmic microwave background anisotrop

Arjun Berera, Thomas W. Kephart

A string theory based inflationary model is developed where the inflaton interacts with a multitude of massive string level states causing dissipation of vacuum energy. Inflation terminates in a warm Universe without the need for reheating.

Arjun Berera

Warm inflation is examined in a multi-field model. Solutions are obtained for expansion e-folds and scalar density perturbations. Nonequilibrium dynamics is restricted to a regime that is displaced only slightly from thermal equilibrium and in which all macroscopic motion is adiabatic. In such a regime, nonequilibrium dynamics is well defined, provided macro

Jan M. L. Martin, Glenisson de Oliveira

Two new schemes for computing molecular total atomization energies (TAEs) and/or heats of formation ($ΔH^\circ_f$) of first-and second-row compounds to very high accuracy are presented. The more affordable scheme, W1 (Weizmann-1) theory, yields a mean absolute error of 0.30 kcal/mol and includes only a single, molecule-independent, empirical parameter. It re

C. Chryssomalakos, J. A. de Azcárraga, J. M. Izquierdo, J. C. Pérez Bueno

We argue that a description of supersymmetric extended objects from a unified geometric point of view requires an enlargement of superspace. To this aim we study in a systematic way how superspace groups and algebras arise from Grassmann spinors when these are assumed to be the only primary entities. In the process, we recover generalized spacetime superalge

Andre de Gouvea, Alexander Friedland, Hitoshi Murayama

Measuring the 7Be solar neutrino flux is crucial towards solving the solar neutrino puzzle. The Borexino experiment, and possibly the KamLAND experiment, will be capable of studying the 7Be neutrinos in the near future. We discuss (1) how the seasonal variation of the Borexino and KamLAND data can be used to measure the 7Be solar neutrino flux in a backgroun

Y. Mizuno, T. Tohyama, S. Maekawa

An effective Hamiltonian is constructed for an insulating cuprate with edge-sharing chains Li2CuO2.The Hamiltonian contains the nearest and next-nearest neighboring intrachain and zigzag-type interchain interactions.The values of the interactions are obtained from the analysis of the magnetic susceptibility, and this system is found to be described as couple

Stephen Bigelow

The Burau representation is a natural action of the braid group B_n on the free Z[t,t^{-1}]-module of rank n-1. It is a longstanding open problem to determine for which values of n this representation is faithful. It is known to be faithful for n=3. Moody has shown that it is not faithful for n>8 and Long and Paton improved on Moody&#39;s techniques to bring

M. Cvetic, H, Lu, J. F. Vazquez-Poritz

We study the absorption probability of minimally-coupled massive scalars by extremal p-branes. In particular, we find that the massive scalar wave equation under the self-dual string background has the same form as the massless scalar wave equation under the dyonic string background. Thus it can be cast into the form of a modified Mathieu equation and solved

M. A. De Andrade, F. Toppan

Clifford algebras and Majorana conditions are analyzed in any spacetime. An index labeling inequivalent $Γ$-structures up to orthogonal conjugations is introduced. Inequivalent charge-operators in even-dimensions, invariant under Wick rotations, are considered. The hermiticity condition on free-spinors lagrangians is presented. The constraints put by the Maj

Simona Cocco, Remi Monasson

A unifying theory of the denaturation transition of DNA, driven by temperature T or induced by an external mechanical torque Gamma is presented. Our model couples the hydrogen-bond opening and the untwisting of the helicoidal molecular structure. We show that denaturation corresponds to a first-order phase transition from B-DNA to d-DNA phases and that the c

Yunqiang Yu, Siming Liu

It is proven that the relativistic charged ball with its charge less than its mass (in natural units) cannot have a non-singular static configuration while its radius approaches its external horizon size. This conclusion does not depend on the details of charge distribution and the equation of state. The involved assumptions are (1) the ball is made of perfe

H. Rieger, F. Igloi

We study the effect of spatial correlations in the quenched disorder on random quantum magnets at and near a quantum critical point. In the random transverse field Ising systems disorder correlations that decay algebraically with an exponent rho change the universality class of the transition for small enough rho and the off-critical Griffiths-McCoy singular

S. S. Avancini, F. F. de Souza Cruz, J. R. Marinelli, D. P. Menezes

We prove that, for the quon algebra, which interpolates between the Bose and Fermi statistics and depends on a free parameter q,it is possible to build an su(2) irreducible representation. One of the consequences of this fact is that the quons couple via the same angular momentum coupling rules obeyed by ordinary bosons and fermions.

Dong-Sheng Du, Zheng-Tao Wei

Cascade mixing provides an elegant place to study the $B^0-\bar{B^0}$ mixing. We use this idea to study the CPT violation caused by $B^0-\bar{B^0}$ mixing. An approximation method is adopted to treat the two complex $B^0-\bar{B^0}$ mixing parameters $θ$ and $ϕ$. A procedure to extract the parameters $θ$ and $ϕ$ is suggested. The feasibility of exploring the

Chong-Sun Chu, Pei-Ming Ho, Yeong-Chuan Kao

By quantizing an open string ending on a D-brane in a nontrivial supergravity background, we argue that there is a new kind of uncertainty relation on a D-brane worldvolume. Furthermore, we fix the form of the uncertainty relations and their dependence on the string coupling constant by requiring them to be consistent with various string theory and M theory

takashi Nakatsukasa, Niels R. Walet, Giu Do Dang

Methods of large amplitude collective motion in the adiabatic limit are examined with a special emphasis on conservation laws. We show that the restriction to point transformations, which is a usual assumption of the adiabatic time-dependent mean-field theory, needs to be lifted. In order to facilitate the application of large amplitude collective motion tec

Denis Bernard

We discuss two possible scenario for the direct cascade in two dimensional turbulent systems in presence of friction which differ by the presence or not of enstrophy dissipation in the inviscid limit.They are distinguished by the existence or not of a constant enstrophy transfer and by the presence of leading anomalous scaling in the velocity three point fun

Jiri Novotny, Miroslav Stohr

As an illustration of general principles, the $W$-boson loop contribution to the amplitude for the decay $H\to γγ$ is calculated within a specific model for the effective lagrangian describing the anomalous gauge boson couplings. Different approaches to the dependence of the result on the scale of new physics $Λ$ are briefly discussed.

Jean-Pierre Eckmann, Esa Jarvenpaa, Maarit Jarvenpaa

Summary of a talk at the conference The Chaotic Universe in Rome, Feb, 1999

Siang Peng Oh

The next generation of astronomical instruments will be able to detect dense pockets of ionized gas created by the first luminous objects. The integrated free-free emission from ionized halos creates a spectral distortion of the Cosmic Microwave Background, greater than the distortion due to the reionized intergalactic medium. Its detection is well within th

S. Fujiyama, M. Takigawa, Y. Ueda, T. Suzuki

We have performed copper NQR experiments in high temperature superconductors YBa_{2}Cu_{4}O_{8}, YBa_{2}Cu_{3}O_{7}, and La_{2-x}Sr_{x}CuO_{4} (x=0.12 and 0.15), using the stimulated echo technique. The stimulated echo intensity is analyzed by a model that includes the spin-lattice relaxation process (T_ {1 }-process) and the fluctuating local field due to n

Keshav Dasgupta, Sunil Mukhi

Compactifications of type IIB string theory on AdS5 x X5, where X5 is an Einstein space, can have one-fourth or half maximal supersymmetry for certain choices of X5. Some of these theories admit exotic domain walls arising from 5-branes wrapping 2-cycles in X5. We explore the relationship among these domain walls, fractional branes and branes stretched on in

Peter Coles, Adrian Melott, Dipak Munshi

It is now well established that galaxies are biased tracers of the distribution of matter, although it is still not known what form this bias takes. In local bias models the propensity for a galaxy to form at a point depends only on the overall density of matter at that point. Hierarchical scaling arguments allow one to build a fully-specified model of the u