October 1998 arXiv papers — page 20

H. Albuquerque, S. Majid

We announce a new approach to the octonions as quasiassociative algebras. We strip out the categorical and quasi-quantum group considerations of our longer paper and present here (without proof) some of the more algebraic conclusions

Dmitry Kleinbock, Gregory Margulis

We present a new approach to metric Diophantine approximation on manifolds based on the correspondence between approximation properties of numbers and orbit properties of certain flows on homogeneous spaces. This approach yields a new proof of a conjecture of Mahler, originally settled by V. Sprindzhuk in 1964. We also prove several related hypotheses of A.

Georgios Daskalopoulos, Stamatis Dostoglou, Richard Wentworth

A gauge theoretic description of the Morgan-Shalen compactification of the $\SL$ character variety of the fundamental group of a hyperbolic surface is given in terms of a natural compactification of the moduli space of Higgs bundles via the Hitchin map.

Georgios Daskalopoulos, Stamatis Dostoglou, Richard Wentworth

We show that the Korevaar-Schoen limit of the sequence of equivariant harmonic maps corresponding to a sequence of irreducible $SL_2({\mathbb C})$ representations of the fundamental group of a compact Riemannian manifold is an equivariant harmonic map to an ${\mathbb R}$-tree which is minimal and whose length function is projectively equivalent to the Morgan

Georgios Daskalopoulos, Richard Wentworth

We study the behavior of the Yang-Mills flow for unitary connections on compact and non-compact oriented surfaces with varying metrics. The flow can be used to define a one dimensional foliation on the space of SU(2) representations of a once punctured surface. This foliation universalizes over Teichmüller space and is equivariant with respect to the action

Lawrence Ein, Bo Ilic, Robert Lazarsfeld

We prove an elementary but somewhat unexpected result about projective embeddings of smooth varieties X whose cotangent bundles are numerically effective. Specifically, we show that the degree of X in any projective embedding must grow (almost) exponentially in the dimension of X.

Michael Farber

In this note I use cup-products and higher Massey products to find topological lower bounds on the number of geometrically distinct critical points of any closed 1-form in a given cohomology class.

Michael Farber, Vladimir Turaev

In this paper we use the results of our previous work in order to compute the phase of the torsion of an Euler structure in terms of its characteristic class. Also, we introduce here a new notion of an absolute torsion, which does not require a choice of any additional topological information (like an Euler structure). We prove that in the case of closed 3-m

Ioseph Buchbinder, Sergei Kuzenko, Burt Ovrut

We review the background field method for general N = 2 super Yang-Mills theories formulated in the N = 2 harmonic superspace. The covariant harmonic supergraph technique is then applied to rigorously prove the N=2 non-renormalization theorem as well as to compute the holomorphic low-energy action for the N = 2 SU(2) pure super Yang-Mills theory and the lead

P. Menotti

We work out the constraints imposed by SL(2C) invariance for sphere topology and modular invariance for torus topology, on the discretized form of Liouville action in Polyakov's non local covariant form. These are sufficient to completely fix the discretized action except for the overall normalization constant and a term which in the continuum limit goes

M. D. Maia, E. M. Monte

A dynamical theory of hypersurface deformations is presented. It is shown that a (n+1)-dimensional space-time can be always foliated by pure deformations, governed by a non zero Hamiltonian. Quantum deformations states are defined by Schroedinger's equation constructed with the corresponding deformation Hamiltonian operator, interpreted as the generator

M. Golenishcheva-Kutuzova, D. Lebedev

In this paper we generalize the fermionic approach to the KP hierarchy sudgested in the papers of Kyoto school 1981-1984 (Sato,Jimbo, Miwa...). The main idea is that the components of the intertwiningoperators are in some sense a generalization of free fermions for $gl_{\infty}$. We formulate in terms of intertwining operators the integrable hierarchies rela

Robert Bluhm, Alan Kostelecky, Neil Russell

Signals for CPT and Lorentz violation at the Planck scale may arise in hydrogen and antihydrogen spectroscopy. We show that certain 1S-2S and hyperfine transitions can exhibit theoretically detectable effects unsuppressed by any power of the fine-structure constant.

T-M. Yan

We review the development in the field of lepton pair production since proposing parton-antiparton annihilation as the mechanism of massive lepton pair production. The basic physical picture of the Drell-Yan model has survived the test of QCD, and the predictions from the QCD improved version have been confirmed by the numerous experiments performed in the l

James M. Cline

In collaboration with G.D. Moore, the electroweak phase transition in the minimal supersymmetric standard model is studied using the two-loop effective potential. We make a comprehensive search of the MSSM parameter space consistent with electroweak baryogenesis, taking into account various factors: the latest experimental constraints on the Higgs boson mass

J. A. Casas, A. Ibarra, C. Muñoz

We analyze the constraints that a correct phenomenology and the absence of dangerous charge and color breaking (CCB) minima or unbounded from below (UFB) directions impose on the parameter space of different superstring and M-theory scenarios. Namely, we analyze in detail the case where supersymmetry (SUSY) breaking is driven by non-vanishing dilaton and/or

Dietrich Bodeker

I try to explain some recent progress in understanding the non-perturbative dynamics of hot non-Abelian gauge theories. The non-perturbative physics is due to soft spatial momenta $|\vec{p}|\sim g^2 T$ where $g$ is the gauge coupling and $T$ is the temperature. An effective theory for the soft field modes is obtained by integrating out the field modes with m

Alan. R. White

A high-energy, transverse momentum cut-off, solution of QCD is outlined. Regge pole and ``single gluon'' properties of the pomeron are directly related to the confinement and chiral symmetry breaking properties of the hadron spectrum. This solution, which corresponds to a supercritical phase of Reggeon Field Theory, may only be applicable to QCD with

Alessandro Drago

A brief overview of various problems related to the description of a polarized proton in quark models is presented. Structure functions are discussed both for longitudinal and transverse polarization. A recently introduced quantity, relevant in the study of single-spin asymmetries, is shown to be in principle non-vanishing when computed in chiral models.

Jim Cline, Jose Espinosa, Guy D. Moore, Antonio Riotto

We study the scenario of electroweak baryogenesis mediated by nonsuperconducting cosmic strings. This idea relies upon electroweak symmetry being restored in a region around the core of the topological defect so that, within this region, the rate of baryon number violation is enhanced. We compute numerically how effectively baryon number is violated along a

Andrzej J. Buras, Robert Fleischer

We present a general parametrization of $B^\pm\toπ^\pm K, π^0K^\pm$ and $B_d\toπ^0 K, π^\mp K^\pm$ decays, taking into account both electroweak penguin and rescattering effects. This formalism allows -- among other things -- an improved implementation of the strategies that were recently proposed by Neubert and Rosner to probe the CKM angle $γ$ with the help

M. Jamin, A. Pich

The talk presents an update of the bottom quark mass determination from QCD moment sum rules for the Upsilon system by the authors. Employing the MS_bar scheme, we find m_b(m_b) = 4.19 +- 0.06 GeV. The differences to our previous analysis will be discussed and we comment on the determination of the pole mass for the bottom quark.

Hou Defu, Stefan Ochs, Li Jiarong

We calculate the relaxation time self-consistently to study the damping of collective color modes and the color conductivity in a QGP by deriving self-consistent equations for the damping rates of gluons and quarks to leading order QCD by TFD including a chemical potential for quarks. We show that the damping rates are not sensitive to the chemical potential

Shi-Lin Zhu

The light cone QCD sum rules are employed to calculate the $πN N(1535)$ coupling $g_{πN N^\ast}$. We study the two point correlation function of two nucleon currents sandwiched between the vacuum and the pion state. The contribution from the excited states and the continuum is subtracted cleanly through double Borel transformation with respect to the nucleon

Tianjun Li

This paper has been withdrawn by the author(s), due a crucial sign error in Eqn. 1.

A. V. Kotikov, G. Parente

We investigate the Q2 evolution of parton distributions at small x values, recently obtained in the case of soft initial conditions. The results are in excellent agreement with deep inelastic scattering experimental data from HERA.

Cheuk-Yin Wong

We use the Drell-Yan differential distribution dN_{DY}^{AB}/dE_T in high-energy nucleus-nucleus collisions to obtain a relation between the transverse energy E_T and the impact parameter b. Such a relation is then utilized to study the transverse-energy dependence of J/psi production in Pb-Pb collisions, using the J/psi absorption model presented previously.

Rajan Gupta

We present evidence for improvement with tadpole improved clover fermions based on an analysis of the chiral behavior of $B_K$ and the quark condensate. Also presented are a comparison of the mass splittings in the baryon octet and decuplet, a calculation of $c_A$ using standard 2-point correlation functions, and the problem of zero modes of the Dirac operat

Tanmoy Bhattacharya

This talk summarizes the quenched calculation of $f_B$ and $f_{B_s}$ presented in hep-lat/9801038. The heavy quark is simulated using an $O(1/M^2)$ improved NRQCD action, and the tadpole improved clover action is used for the light quarks. The axial current includes the $O(1/M)$ corrections in one-loop perturbation theory and the $O(1/M^2)$ ones at tree-leve

CDF Collaboration, D0 Collaboration

We have combined recently published leptoquark results from the CDF and D0 Collaborations which yielded 95% CL lower limits on the first generation scalar leptoquark mass of 213 GeV and 225 GeV, respectively, under assumption of 100% branching fraction of the leptoquark decay into the eq channel. The combined limit from the two experiments is 242 GeV. This i

T. Montaruli, R. Bellotti, F. Cafagna, M. Circella

The design of an Airwatch type space mission can greatly benefit from a flexible simulation code for establishing the values of the main parameters of the experiment. We present here a code written for this purpose. The cosmic ray primary spectrum at very high energies, the atmosphere modelling, the fluorescence yield, the photon propagation and the detector

VES collaboration

The results of patial wave analysis of the omega pi- pi0 system, produced in the reaction pi- Be --> pi+ 2pi- 2pi0 Be at beam momentum of 37 GeV are presented. An indication of the resonant type structure with mass near 1.74 GeV and JpMetha=0-0+ in the omega rho- system was found. The decay branching ratio of a2(1320)- to omega pi- pi0 was measured. A wave w

Helia R. Hollmann, Ruth M. Williams

The initial data in the polygon approach to (2+1)D gravity coupled to point particles are constrained by the vertex equations and the particle equations. We establish the hyperbolic nature of the vertex equations and derive some consequences. In particular we are able to identify the hyperbolic group of motions as discrete analogues of the diffeomorphisms in

L. Herrera, A. Di Prisco

We obtain an expression for the active gravitational mass of a relativistic heat conducting fluid, just after its departure from hydrostatic equilibrium, on a time scale of the order of relaxation time. It is shown that an increase of a characteristic parameter leads to larger (smaller) values of active gravitational mass of collapsing (expanding) spheres, e

M. Yu. Konstantinov

We examine the recent statement by A. Dolgov and I. Novikov that superluminal propagation of light, which is induced by the quantum corrections to the photon propagation in gravitational field, permits non-causal signal propagation. For this purpose we examine the possibility of the existence of non-causal signals in the model case, when characteristic cone

C. -C. Li, J. Yoon, L. W. Engel, D. Shahar

Microwave frequency conductivity, Re($σ_{xx}$), of high quality two-dimensional hole systems (2DHS) in a large perpendicular magnetic field (B) is measured with the carrier density ($n_s$) of the 2DHS controlled by a backgate bias. The high B insulating phase of the 2DHS exhibits a microwave resonance that remains well-defined, but shifts to higher peak freq

Lev P. Gor`kov, J. R. Schrieffer

We argue that inhomogeneity inherent to the presence of periodic supercurrents in the vortex lattice sorts excitations by energies into the ones that are spatially localized and those that perform motion along large Larmour orbits. This energy threshold results in a new mechanism for the de Haas-van Alphen oscillations which enhances oscillations at B<<Hc2,

S-K. Yip, Tin-Lun, Ho

Motivated by the recent success of optical trapping of alkali bosons, we have studied the zeroth sound modes of dilute Fermi gases with arbitrary spin-f, which are spin-S excitations ($0\leq S\leq 2f$). The dispersion of the mode (S) depends on a single Landau parameter $F^{(S)}$, which is related to the scattering lengths of the system through a simple form

A. E. Koshelev, H. Nordborg

Using numerical results obtained within two models describing vortex matter (interacting elastic lines (Bose model) and uniformly frustrated XY-model) we establish universal properties of the melting transition within the linelike regime. These properties, which are captured correctly by both models, include the scaling of the melting temperature with anisot

P. Lemmens, M. Fischer, G. Els, G. Güntherodt

Raman scattering in the quarter-filled spin ladder system alpha&#39;-NaV_2O_5 shows in the dimerized singlet ground state ($T \leq T_{SP}=35K$) an unexpected sequence of three magnetic bound states. Our results suggest that the recently proposed mapping onto an effective spin chain for $T > T_{SP}$ has to be given up in favor of the full topology and exchang

A. Frydman, R. C. Dynes

We have observed a superparamagnetic to ferromagnetic transition in films of isolated Ni grains covered by non-magnetic overlayers. The magnetoresistance (MR) of the films was measured as a function of the overlayer thickness. Initially, the granular Ni films exhibited negative MR curves peaked at H=0. As different materials were deposited onto the grains hy

C. Donati, S. C. Glotzer, P. H. Poole, W. Kob

Using extensive molecular dynamics simulations of an equilibrium, glass-forming Lennard-Jones mixture, we characterize in detail the local atomic motions. We show that spatial correlations exist among particles undergoing extremely large (``mobile&#39;&#39;) or extremely small (``immobile&#39;&#39;) displacements over a suitably chosen time interval. The imm

A. Puglisi, V. Loreto, U. Marini Bettolo Marconi, A. Vulpiani

We address the problem of the so-called ``granular gases&#39;&#39;, i.e. gases of massive particles in rapid movement undergoing inelastic collisions. We introduce a class of models of driven granular gases for which the stationary state is the result of the balance between the dissipation and the random forces which inject energies. These models exhibit a g

G. T. Barkema, Normand Mousseau

Structural mechanisms in disordered materials like amorphous semi-conductors and glasses can be explored with the activation-relaxation technique (ART). The application of a sequence of such mechanisms allows for the generation of well-relaxed structures. The method and its application in the study of the microscopic changes in amorphous silicon and silica g

Robert Shrock, Shan-Ho Tsai

We present exact calculations of the zero-temperature partition function, $Z(G,q,T=0)$, and ground-state degeneracy (per site), $W({G},q)$, for the $q$-state Potts antiferromagnet on a number of families of graphs ${G}$ for which the boundary ${\cal B}$ of regions of analyticity of $W$ in the complex $q$ plane is noncompact and has the properties that (i) in

Kikuo Harigaya

The optical excitations in C$_{60}$ and higher fullerenes, including isomers of C$_{76}$, C$_{78}$, and C$_{84}$, are theoretically investigated. We use a tight binding model with long-range Coulomb interactions, treated by the Hartree-Fock and configuration-interaction methods. We find that the optical excitations in the energy region smaller than about 4 e

Arnaud Buhot

In this paper, I relate the phase separation transition in binary hard-core mixtures in the limit of small size ratio to a bond percolation transition. It allows to estimate the critical packing fraction at the transition as a function of the size ratio and the composition of the mixture for different shapes of objects. The theoretical predictions are in exc

S. Watanabe, Y. Kuramoto, T. Nishino, N. Shibata

The ground state properties of the one-dimensional Kondo lattice with an f^2 configuration at each site are studied by the density matrix renormalization group method. At half-filling, competition between the Kondo exchange J and the antiferromagnetic intra f-shell exchange I leads to reduction of energy gaps for spin, quasi-particle and charge excitations.

E. Kanzieper, V. Freilikher

Higher order parametric level correlations in disordered systems with broken time-reversal symmetry are studied by mapping the problem onto a model of coupled Hermitian random matrices. Closed analytical expression is derived for parametric density-density correlation function which corresponds to a perturbation of disordered system by a multicomponent flux.

D. Andru Vangheli, H. Covlescu, Gh. Ardelean, C. Stelia

Magnetic fluids are colloidal suspensions of ferromagnetic particles covered with a surfactant layer, dispersed in a host liquid. The existence of cooperative phenomena in such magnetic colloidal systems, makes the determining of their physical properties a difficult task. In the framework of statistical mechanics, taking into consideration interparticle int

K. Binder, M. Mueller, F. Schmid, A. Werner

We consider an interface between two demixed A and B phases, confined in a thin film between two antisymmetric walls, one of which prefers A and the other B. Above the wetting transition, the interface is stabilized in the center of the film. Based on a suitable extension of the Cahn-Hilliard gradient-square theory in combination with the capillary wave theo

Jeroen B. A. N. van Hoof, Kees M. Schep, Arne Brataas, Gerrit E. W. Bauer

Electron transport limited by the rotating exchange-potential of domain walls is calculated in the ballistic limit for the itinerant ferromagnets Fe, Co, and Ni. When realistic band structures are used, the domain wall magnetoresistance is enhanced by orders of magnitude compared to the results for previously studied two-band models. Increasing the pitch of

Colin Denniston, Hao Li

We study, using simulations, the steady-state flow of dry sand driven by gravity in two-dimensions. An investigation of the microscopic grain dynamics reveals that grains remain separated but with a power-law distribution of distances and times between collisions. While there are large random grain velocities, many of these fluctuations are correlated across

S. Gluzman, V. I. Yukalov

A general analytical method is developed for describing crossover phenomena of arbitrary nature. The method is based on the algebraic self-similar renormalization of asymptotic series, with control functions defined by crossover conditions. The method can be employed for such difficult problems for which only a few terms of asymptotic expansions are availabl

Hiroyuki Mori

We studied effects of random potentials and roles of electron-electron interactions in the gapless phase of coupled Hubbard chains, using a renormalization group technique. For non-interacting electrons, we obtained the localization length proportional to the number of chains, as already shown in the other approaches. For interacting electrons, the localizat

J. M. Deutsch

The equilibrium properties of isolated ring molecules were investigated using an off-lattice model with no excluded volume but with dynamics that preserve the topological class. Using an efficient set of long range moves, chains of more than 2000 monomers were studied. Despite the lack of any excluded volume interaction, the radius of gyration scaled like th

J. R. Bond, L. Kofman, D. Pogosyan, J. Wadsley

We review the main theoretical aspects of the structure formation paradigm which impinge upon wide angle surveys: the early universe generation of gravitational metric fluctuations from quantum noise in scalar inflaton fields; the well understood and computed linear regime of CMB anisotropy and large scale structure (LSS) generation; the weakly nonlinear reg

Uros Seljak, Matias Zaldarriaga

We propose a method to extract the projected power spectrum of density perturbations from the distortions in the cosmic microwave background (CMB). The distortions are imprinted onto the CMB by the gravitational lensing effect and can be extracted using a combination of products of CMB derivatives. We show that future CMB experiments such as Planck will be a

L. Guzzo, J. G. Bartlett, A. Cappi

We discuss the behaviour of the redshift- and real-space correlation functions from the ESO Slice Project (ESP) galaxy redshift survey. xi(s) for the whole survey is positive out to ~80/h Mpc, with a smooth break from a shallow power law. Comparison to xi(s) from two other wide-angle, moderately deep surveys, the LCRS and Stromlo-APM, shows a very good agree

E. Zucca, G. Zamorani, P. Vettolani

We summarise the main results obtained over the last two years by the ESO Slice Project (ESP) redshift survey, concerning the luminosity function and mean density of galaxies, and their implications for the galaxy number counts at bright magnitudes. The bj-band luminosity function is characterised by a steep faint-end, which raises above a &#34;global&#34; S

Reuven Ramaty, Natalie Mandzhavidze

We briefly review the theory of gamma ray production in solar flares and present the highlights of the observations and their implications. Specifically: (i) the gamma ray data show that a large fraction of the released flare energy is in accelerated ions, mostly around 1 MeV/nucleon; (ii) the accelerated He-3, heavy ion, and relativistic electron abundances

Robert A. Benjamin, Evan D. Skillman, Derck P. Smits

We have combined the detailed He I recombination model of Smits with the collisional transitions of Sawey & Berrington in order to produce new accurate helium emissivities that include the effects of collisional excitation from both the 2 (3)S and 2 (1) S levels. We present a grid of emissivities for a range of temperature and densities along with analytical

M. Guainazzi, G. Vacanti, A. Malizia, K. S. O&#39;Flaherty

The BL Lac object Mkn~421 was observed three times by the X-ray observatory BeppoSAX in consecutive days during 1997 April and May. The source was in a quiescent state, with an average 2-10 keV flux of 9.0 x 10^(-11) erg/cm/cm/s. Flux variation by a factor of ~2 on timescales as short as a few 10 ks were more pronounced in the hard (i.e. above ~3 keV) than i

Rosalba Perna, Abraham Loeb

The degree of beaming in Gamma-Ray Bursts (GRBs) is currently unknown. The uncertainty in the gamma-ray beaming angle, theta, leaves the total energy release (proportional to theta^2) and the event rate per galaxy (proportional to 1/theta^2) unknown to within orders of magnitude. Since the delayed radio emission of GRB sources originates from a mildly relati

Henry E. Kandrup, John Drury

This paper summarises a numerical investigation which aimed to identify and characterise regular and chaotic behaviour in time-dependent Hamiltonians H(r,p,t) = p^2/2 + U(r,t), with U=R(t)V(r) or U=V[R(t)r], where V(r) is a polynomial in x, y, and/or z, and R = const * t^p is a time-dependent scale factor. When p is not too negative, one can distinguish betw

G. Fiorentini, V. Berezinsky, S. Degl&#39;Innocenti, B. Ricci

The excess of highest energy solar-neutrino events recently observed by Superkamiokande can be in principle explained by anomalously high $hep$-neutrino flux $Φ_ν(hep)$. Without using SSM calculations, from the solar luminosity constraint we derive that $Φ_ν(hep)/S_{13}$ cannot exceed the SSM estimate by more than a factor three. If one makes the additional

D. Grupe, Beverley J. Wills, D. Wills, Karen M. Leighly

We have surveyed the optical linear polarimetric properties of 65 soft X-ray selected ROSAT Active Galactic Nuclei (AGN). Most of these sources show low polarization (<1%) and no optical reddening. This is in agreement with the X-ray results suggesting a direct view on the center. However, two of our AGN show polarization as high as 7--8% and high reddening.

Jens Kube, Boris T. Gaensicke, Klaus Beuermann

We have developed a 3D computer model of polars which includes the accretion stream, the accretion column, the secondary star, and the white dwarf. Each component is represented by a fine grid of surface elements. With brightness values attributed to each surface element, this model generates synthetic light curves of the various components. As a first appli

Biman Nath, Shiv Sethi, Yuri Shchekinov

Lyman-$α$ absorption systems at $z \sim 3$ with $N_{HI} \ga 3 \times 10^{14}$ cm$^{-2}$ have been found to be enriched with a mean metallicity of $Z/Z_{\odot} \sim 10^{-2.5}$, and a large scatter in the metallicity. It is reasonable to assume that the process of initial enrichment of the intergalactic medium (IGM) at $z \ga 3$ also produced dust grains. We e

O. Bienaymé

The velocity distribution of neighbouring stars is deduced from the Hipparcos proper motions. We have used a classical Schwarzschild decomposition and also developed a dynamical model for quasi-exponential stellar discs. This model is a 3-D derivation of Shu&#39;s model in the framework of Stäckel potentials with three integrals of motion. We determine the s

Reuven Ramaty, Richard Lingenfelter

Be abundances of old, low metallicity halo stars have major implications on cosmic-ray origin, requiring acceleration out of fresh supernova ejecta. The observed, essentially constant Be/Fe fixes the Be production per SNII, allowing the determination of the energy supplied to cosmic rays per SNII. The results rule out acceleration out of the metal-poor ISM,

J. Wilms, M. A. Nowak, J. B. Dove, K. Pottschmidt

Of all known persistent stellar-mass black hole candidates, only LMC X-1 and LMC X-3 consistently show spectra that are dominated by a soft, thermal component. We present results from long (170ksec) Rossi X-ray Timing Explorer (RXTE) observations of LMC X-1 and LMC X-3 made in 1996 December. The spectra can be described by a multicolor disk blackbody plus an

AAke Nordlund, Paolo Padoan

The question of the shape of the density PDF for supersonic turbulence is addressed, using both analytical and numerical methods. For isothermal supersonic turbulence, the PDF is Log-Normal, with a width that scales approximately linearly with the Mach number. For a polytropic equation of state, with an effective gamma smaller than one, the PDF becomes skewe

Sebastian M. Pascarelle, Kenneth M. Lanzetta, Alberto Fernandez-Soto

Studies of the Hubble Deep Field (HDF) and other deep surveys have revealed an apparent peak in the ultraviolet (UV) luminosity density, and therefore the star-formation rate density, of the Universe at redshifts 1<z<2. We use photometric redshifts of galaxies in the HDF to determine the comoving UV luminosity density and find that, when errors (in particula

I. A. Lubshevsky, V. V. Gafiychuk, M. G. Keijan

Within the framework of the frozen temperature approximation we develop a strongly-nonlinear theory of one-dimensional pattern formation during directional solidification of binary mixture under nonequilibrium segregation. In the case of small partition coefficient the full problem is reduced to the system of two ordinary differential equations describing th

K. Jacobs

In this thesis we consider primarily the dynamics of quantum systems subjected to continuous observation. In the Schr\"{o}dinger picture the evolution of a continuously monitored quantum system, referred to as a `quantum trajectory', may be described by a stochastic equation for the state vector. We present a method of deriving explicit evolution operators f

Itzhak Bars

The massive non-relativistic free particle in d-1 space dimensions has an action with a surprizing non-linearly realized SO(d,2) symmetry. This is the simplest example of a host of diverse one-time-physics systems with hidden SO(d,2) symmetric actions. By the addition of gauge degrees of freedom, they can all be lifted to the same SO(d,2) covariant unified t

M. S. Marley, C. Gelino, D. Stephens, J. Lunine

The reflected spectra of extrasolar giant planets are primarily influenced by Rayleigh scattering, molecular absorption, and atmospheric condensates. We present model geometric albedo and phase integral spectra and Bond albedos for planets and brown dwarfs with masses between 0.8 and 70 Jupiter masses. Rayleigh scattering predominates in the blue while molec

Wu Zhong Chao

In the absence of a general no-boundary proposal for open creation, the complex constrained instanton is used as the seed for the open pair creations of black holes in the Kerr-Newman-anti-de Sitter family. The relative probability of the chargeless and nonrotating black hole pair is the exponential of the negative of the entropy, and that of the charged and

Vladimir A. Kazakov, Ivan K. Kostov, Nikita Nekrasov

We study the regularized correlation functions of the light-like coordinate operators in the reduction to zero dimensions of the matrix model describing $D$-particles in four dimensions. We investigate in great detail the related matrix model originally proposed and solved in the planar limit by J. Hoppe. It also gives the solution of the problem of 3-colori

Mira Dey, Ignazio Bombaci, Jishnu Dey, Subharthi Ray

We derive an equation of state (EOS) for strange matter, starting from an interquark potential which (i) has asymptotic freedom built into it, (ii) shows confinement at zero baryon density and deconfinement at high density and (iii) gives a stable configuration for chargeless, beta--stable quark matter. This EOS is then used to calculate the structure of Str

M. Boettcher, E. P. Liang

The time-dependent Comptonized output of a cool soft X-ray source drifting inward through an inhomogeneous hot inner disk or corona is numerically simulated. We propose that this scenario can explain from first principles the observed trends in the hard time lags and power spectra of the rapid aperiodic variability of the X-ray emission of Galactic black-hol

Todd L. Veldhuizen, Dennis Gannon

We describe Active Libraries, which take an active role in compilation. Unlike traditional libraries which are passive collections of functions and objects, Active Libraries may generate components, specialize algorithms, optimize code, configure and tune themselves for a target machine, and describe themselves to tools (such as profilers and debuggers) in a

I. Amirkhanov, I. Puzynin, A. Tarasov, O. Voskresenskaya

The influence of strong $π^+π^-$ interaction of the behaviour of pionium nS-state wave functions at small distance are investigated both analytically (perturbatively) and so numerically. It is shown that in the whole the accounting of strong interaction results in multiplying of pure Coulomb pionium wave functions by some function practically independent on

Zhi-zhong Xing

We show that new physics, either from CPT violation in B^0-\bar{B}^0 mixing or from ΔB = -ΔQ transitions, may lead to an opposite-sign dilepton asymmetry of neutral B-meson decays. Both effects have the same time-dependent behavior and therefore are in general indistinguishable from each other. We also clarify some ambiguity associated with the constraint on

Toshiya Suzuki

We investigate BPS properties of the charged soliton solutions of D-brane worldvolume theory, which is described by the supersymmetric Dirac-Born-Infeld action, by means of the N=2 target-space supersymmetry algebra. Our results agree with those obtained previously. We also extend our BPS analysis to the case where axion background exists.

R. Werner, C. Gros, M. Braden

Using RPA results, mean field theory, and refined data for the polarization vectors we determine the coupling constants of the four Peierls-active phonon modes to the spin chains of CuGeO_3. We then derive the values of the coupling of the spin system to the linear ionic displacements, the bond lengths and the angles between bonds. Our values are consistent

S. Chaturvedi, V. Srinivasan, G. S. Agarwal

It is shown that the the quantum phase space distributions corresponding to a density operator $ρ$ can be expressed, in thermofield dynamics, as overlaps between the state $\mid ρ>$ and &#34;thermal&#34; coherent states. The usefulness of this approach is brought out in the context of a master equation describing a nonlinear oscillator for which exact expres

J. Blümlein, S. Kurth

A systematic study is performed on the finite harmonic sums up to level four. These sums form the general basis for the Mellin transforms of all individual functions $f_i(x)$ of the momentum fraction $x$ emerging in the quantities of massless QED and QCD up to two--loop order, as the unpolarized and polarized splitting functions, coefficient functions, and h

Shi-Lin Zhu, Yuan-Ben Dai

The radiative decays of heavy baryons and lowest three doublets of heavy mesons are studied with the light cone QCD sum rules in the leading order of heavy quark effective theory.

T. Timberlake, L. E. Reichl

Avoided crossings are common in the quasienergy spectra of strongly driven nonlinear quantum wells. In this paper we examine the sinusoidally driven particle in a square potential well to show that avoided crossings can alter the structure of Floquet states in this system. Two types of avoided crossings are identified: on type leads only to temporary changes

C. Cabrillo, J. I. Cirac, P. Garcia-Fernandez, P. Zoller

We propose a scheme to create distant entangled atomic states. It is based on driving two (or more) atoms with a weak laser pulse, so that the probability that two atoms are excited is negligible. If the subsequent spontaneous emission is detected, the entangled state is created. We have developed a model to analyze the fidelity of the resulting state as a f

J. Dittmann

The Riemannian Bures metric on the space of (normalized) complex positive matrices is used for parameter estimation of mixed quantum states based on repeated measurements just as the Fisher information in classical statistics. It appears also in the concept of purifications of mixed states in quantum physics. Here we determine its scalar curvature and Ricci

Sanjay Kumar, D. Mathur

The possibility of electron attachment to the valence $^{3}Π$ state of CO is examined using an {\it ab initio} bound-state multireference configuration interaction approach. The resulting resonance has $^{4}Σ^{-}$ symmetry; the higher vibrational levels of this resonance state coincide with, or are nearly coincident with, levels of the parent $a^{3}Π$ state.

Dirk Kreimer

We report on some conceptual changes in our present understanding of Quantum Field Theory and muse about possible consequences for the understanding of $v>c$ signals.

Zhou Haijun, Ou-Yang Zhong-can

The Kirchhoff elastic theory of thin filaments with spontaneous curvature is employed in the understanding of the onset of the kink transitions observed in short DNA rings. Dynamical analysis shows that when its actual curvature is less than some threshold value determined by the spontaneous curvature, a circular DNA will begin to buckle to other shapes. The

Ulf-G. Meißner

I critically review the status of computations of threshold pion production in proton-proton collisions in the framework of effective field theory approaches or variants thereof. I also present the results of a novel diagrammatic scheme.

A. Ramos, E. Oset

The s-wave meson-nucleon interaction in the S=-1 sector is studied by means of a coupled-channel Lippmann Schwinger equation, using the lowest order chiral Lagrangian and a cut off to regularize the loop integrals. The position and width of the Lambda(1405) resonance and the K^- p scattering cross sections at low energies are well reproduced. The inclusion o

R. L. Workman

Recent determinations of the E2/M1 ratio are reviewed. Many aspects of these studies have been questioned. Here we focus on the selection of a database, methods used in the extraction of this ratio, and interpretation(s) of the results.

Angsula Ghosh, Sadhan K. Adhikari, B. Talukdar

The role of dimensional regularization is discussed and compared with that of cut-off regularization in some quantum mechanical problems with ultraviolet divergence in two and three dimensions with special emphasis on the nucleon-nucleon interaction. Both types of renormalizations are performed for attractive divergent one- and two-term separable potentials,