October 1999 arXiv papers — page 12

Yoshinobu Kuramashi

Recent developments in lattice QCD calculation of weak matrix elements involving light quarks are described. We focus on four topics: $B_K$ with the Kogut-Susskind and Wilson quark actions, $ΔI=1/2$ rule, proton decay matrix elements and the application of domain wall QCD to calculation of weak matrix elements.

John Ellison

We present recent results from CDF and D0 on W and Z production cross sections, the width of the W boson, tau-e universality in W decays, trilinear gauge boson couplings, and on the observation of Z -> b bbar.

G. D'Agostini

This paper is meant as a contribution to the often debated subject of how to combine data which appear to be in mutual disagreement. As a practical example, the epsilon-prime/epsilon determinations have been considered.

D. Abbaneo

Studies od the production of orbitally excited charmed and charmed strange mesons in e+e- collisions, performed by the LEP collaborations are reviewed. Measurements of the production rates of orbitally excited charmed mesons in semileptonic b decays are presented. Searches for charmed meson radial excitations are also briefly discussed.

Hiroki Yajima, Kei-ichi Maeda, Hidetoshi Ohkubo

In one-loop string effective action, we study a generality of non-singular cosmological solutions found in the isotropic and homogeneous case. We discuss Bianchi I and IX type spacetimes. We find that nonsingular solutions still exist in Bianchi I model around nonsingular flat Friedmann solutions. On the other hand, we cannot find any nonsingular solutions i

Olivier Sarbach, Markus Heusler, Othmar Brodbeck

A gauge and coordinate invariant perturbation theory for self-gravitating non-Abelian gauge fields is developed and used to analyze local uniqueness and linear stability properties of non-Abelian equilibrium configurations. It is shown that all admissible stationary odd-parity excitations of the static and spherically symmetric Einstein-Yang-Mills soliton an

P. Fröbrich, P. J. Jensen, P. J. Kuntz

The reorientation of the magnetization of a ferromagnetic monolayer is calculated with the help of many-body Green's function theory. This allows, in contrast to other spin wave theories, a satisfactory calculation of magnetic properties over the entire temperature range of interest since interactions between spin waves are taken into account. A Heisenbe

C. A. Bustamante, M. I. Molina

We show that nonlinear tight-binding lattices of different geometries and dimensionalities, display an universal selftrapping behavior. First, we consider the single nonlinear impurity problem in various tight-binding lattices, and use the Green's function formalism for an exact calculation of the minimum nonlinearity strength to form a stationary bound

Matteo Palassini, A. P. Young

We investigate the ground state structure of Ising spin glasses in zero magnetic field by determining how the ground state changes in a fixed finite block far from the boundaries when the boundary conditions are changed. We find, both in two and three dimensions, that the probability of a change in the block ground state configuration tends to zero as the sy

K. Park, N. Meskini, J. K. Jain

The activation gaps for fractional quantum Hall states at filling fractions $ν=n/(2n+1)$ are computed for heterojunction, square quantum well, as well as parabolic quantum well geometries, using an interaction potential calculated from a self-consistent electronic structure calculation in the local density approximation. The finite thickness is estimated to

Jian-Xin Zhu, C. S. Ting

The proximity effect, quasiparticle transport, and local magnetic moment in ferromagnet--d-wave superconductor junctions with {110}-oriented interface are studied by solving self-consistently the Bogoliubov-de Gennes equations within an extended Hubbard model. It is found that the proximity induced order parameter oscillates in the ferromagnetic region. The

Wannapong Triampo, Timo Aspelmeier, Beate Schmittmann

We investigate the disordering of an initially phase-segregated binary alloy, due to a highly mobile defect which couples to an electric or gravitational field. Using both mean-field and Monte Carlo methods, we show that the late stages of this process exhibit dynamic scaling, characterized by a set of exponents and scaling functions. A new scaling variable

Tomohiro Sasamoto

The one-dimensional partially asymmetric simple exclusion process with open boundaries is considered. The stationary state, which is known to be constructed in a matrix product form, is studied by applying the theory of q-orthogonal polynomials. Using a formula of the q-Hermite polynomials, the average density profile is computed in the thermodynamic limit.

Christian von Ferber, Yurij Holovatch, Arben Jusufi, Christos N. Likos

We derive the short distance interaction of star polymers in a colloidal solution. We calculate the corresponding force between two stars with arbitrary numbers of legs f_1 and f_2. We show that a simple scaling theory originally derived for high f_1, f_2 nicely matches with the results of elaborated renormalization group analysis for f_1 + f_2 =< 6 generali

Christian von Ferber, Yurij Holovatch

We study the properties of diffusion controlled reactions with traps or reaction sites attached to polymer chains or to a star polymer. Using a field theoretical renormalization group approach we obtain the scaling of the moments of concentration of diffusing particles near the core of a star polymer and calculate numerical values of the exponents governing

F. Agullo-Rueda, E. E. Mendez, N. Bojarczuk, S. Guha

We have used Raman spectroscopy to study indium nitride thin films grown by molecular beam epitaxy on (111) silicon substrates at temperatures between 450 and 550 C. The Raman spectra show well defined peaks at 443, 475, 491, and 591 cm{-1}, which correspond to the A_1(TO), E_1(TO), E_2^{high}, and A_1(LO) phonons of the wurtzite structure, respectively. In

A. G. Mal&#39;shukov, K. A. Chao

We have shown that in narrow 2D semiconductor channels the D&#39;yakonov-Perel&#39; spin relaxation rate is strongly reduced. This relaxation slowdown appears in special waveguide diffusion modes which determine the propagation of spin density in long channels. Experiments are suggested to detect the theoretically predicted effects. A possible application is

R. Lopez-Sandoval, G. M. Pastor

A density functional theory for many-body lattice models is considered in which the single-particle density matrix is the basic variable. Eigenvalue equations are derived for solving Levy&#39;s constrained search of the interaction energy functional W, which is expressed as the sum of Hartree-Fock energy and the correlation energy E_C. Exact results are obta

Brandon Carter, David Langlois, Reinhard Prix

This work is the sequel of a previous investigation of stationary and cylindrically symmetric vortex configurations for simple models representing an incompressible non-relativistic superconductor in a rigidly rotating background. In the present paper, we carry out our analysis with a generalized Ginzburg-Landau description of the superconductor, which provi

J. A. Sauls, Y. Lee, T. M. Haard, W. P. Halperin

In superfluid 3He-B the off-resonant coupling of the J=2-, M=+/- 1 order parameter collective modes to transverse current excitations stabilizes propagating transverse waves with low damping for frequencies above that of the J=2- modes. Right- (RCP) and left circularly polarized (LCP) transverse modes are degenerate in zero field; however, a magnetic field w

E. Z. Kuchinskii, M. V. Sadovskii

We analyze superconducting state (both s and d - wave) in a simple exactly solvable model of pseudogap state, induced by short - range order fluctuations (e.g. antiferromagnetic), which is based upon model Fermi - surface with &#34;hot patches&#34;. It is shown that superconducting energy gap averaged over these fluctuations is non zero even for the temperat

Stefan Wessel, Stephan Haas

A theoretical description is presented for low-temperature magnetic-field induced three-dimensional (3D) ordering transitions in strongly anisotropic quantum antiferromagnets, consisting of weakly coupled antiferromagnetic spin-1/2 chains and ladders. First, effective continuum field theories are derived for the one-dimensional subsystems. Then the Luttinger

M. Pustilnik, Y. Avishai, K. Kikoin

We study a small spin-degenerate quantum dot with even number of electrons, weakly connected by point contacts to the metallic electrodes, and subject to an external magnetic field. If the Zeeman energy B is equal to the single-particle level spacing $Δ$ in the dot, the ground state of the dot becomes doubly degenerate, and the system exhibits Kondo effect,

Shin-itiro Goto, Kazuhiro Nozaki

By means of an updated renormalization method, we construct asymptotic expansions for unstable manifolds of hyperbolic fixed points in the double-well map and the dissipative Hénon map, both of which exhibit the strong homoclinic chaos. In terms of the asymptotic expansion, a simple formulation is presented to give the first homoclinic point in the double-we

Fei Zhang, Dennis J. Isbister, Denis J. Evans

We study the use of the Evans Nonequilibrium Molecular Dynamics (NEMD) heat flow algorithm for the computation of the heat conductivity in one-dimensional lattices. For the well-known Fermi-Pasta-Ulam (FPU) model, it is shown that when the heat field strength is greater than a certain critical value (which depends on the system size) solitons can be generate

T. J. Davidge

Near-infrared images obtained with the Canada-France-Hawaii Telescope (CFHT) Adaptive Optics Bonnette (AOB) are used to investigate the stellar content within 18 arcsec of the center of the Local Group spiral galaxy M33. AGB stars with near-infrared spectral-energy distributions similar to those of giants in the solar neighborhood and Baade&#39;s Window are

J. Perea, A. del Olmo, L. Verdes-Montenegro, M. S. Yun

New redshift surveys of galaxies in the field of compact groups have discovered a population of faint galaxies which act as satellites orbiting in the potential well of the bright group. Here we analyze the mass distribution of the groups by comparing the mass derived from the bright members and the mass obtained from the satellite galaxies. Our analysis ind

Steven P. Ruden

This paper reviews the dynamics of the growth of solid particles from micron-sized dust grains to planets in protostellar accretion disks. The formation and orbital evolution of giant protoplanets is also discussed.

A. van Teeseling, B. T. Gaensicke, K. Beuermann, S. Dreizler

We present ultraviolet observations of the supersoft X-ray source RXJ0439.8-6809 obtained with the Hubble Space Telescope Imaging Spectrograph. The ultraviolet spectrum is a very blue continuum overlayed with interstellar absorption lines. The observed broad Lyman alpha absorption line is consistent with an interstellar column density of neutral hydrogen Nh=

Pablo Dmitruk, Daniel Gomez

We report preliminary results from a series of numerical simulations of the reduced magnetohydrodynamic equations, used to describe the dynamics of magnetic loops in active regions of the solar corona. A stationary velocity field is applied at the photospheric boundaries to imitate the driving action of granule motions. A turbulent stationary regime is reach

Malcolm Fairbairn

The C(12)+C(12) => Ne(20)+He(4) fusion reaction rate is shown to be extremely sensitive to variations in the strong coupling constant. Connection with the strong coupling constant is established by using the one boson exchange potential for the nuclear forces and then relating the meson masses and coupling constants of this model to QCD. The implications of

Mikhail V. Medvedev

We demostrate that the measurement of fluctuations of polarization due to the galactic interstellar scintillations may be used to study the structure of the radiation field at compact radio sources. We develop a mathematical formalism and demonstrate it on a simple analytical model in which the scale of the polarization variation through the source is compar

Eric S. Perlman

With their rapid, violent variability and broad featureless continuum emission, blazars have puzzled astronomers for over two decades. Today blazars represent the only extragalactic objects detected in high-energy gamma-rays. Their spectral energy distributions (SEDs) are characteristically double-humped, with lower-energy emission originating as synchrotron

S. B. Popov, M. Colpi, A. Treves, R. Turolla

The paucity of old isolated accreting neutron stars in ROSAT observations is used to derive a lower limit on the mean velocity of neutron stars at birth. The secular evolution of the population is simulated following the paths of a statistical sample of stars for different values of the initial kick velocity, drawn from an isotropic Gaussian distribution wit

A. Georgakakis, B. Mobasher, L. Cram, A. Hopkins

Using the Phoenix radio survey, a homogeneous survey selected at 1.4GHz and covering an area of ~3deg^2, we analyse the clustering of the sub-mJy radio population using angular correlation function analysis. Extensive simulations are carried out to investigate the significance of the estimated angular correlation amplitudes. Our analysis show that for the S_

Barbara Lanzoni, Gary A. Mamon, Bruno Guiderdoni

The merging history of dark matter halos is computed with the Merging Cell Model proposed by Rodrigues & Thomas (1996). While originally discussed in the case of scale-free power spectra, it is developed and tested here in the framework of the cold dark matter cosmology. The halo mass function, the mass distribution of progenitors and child halos, as well as

A. Biviano, L. Metcalfe, B. Altieri, K. Leech

We present imaging results and source counts from a deep ISOCAM cosmological survey at 15 microns, through gravitationally lensing galaxy clusters. We take advantage of the cluster gravitational amplification to increase the sensitivity of our survey. We detect a large number of luminous mid-IR sources behind the cluster lenses, down to very faint fluxes, wh

Myfanwy Bryce, Garrelt Mellema

In this paper we describe the results of the first optical kinematic study of the planetary nebula BD+30 3639. This system has a central star of the Wolf-Rayet type and is believed to be fairly young. Emission line spectra were obtained at high spectral and spatial resolution using the Utrecht echelle spectrometer at the William Herschel Telescope. These spe

Francesca D&#39;Antona

I list the characteristic features of Globular Cluster (GC) HR diagrams which provide a complete test of the stellar evolution of low mass stars: morphologies describing the different evolutionary phases, number ratios and luminosity functions, which add quantitative information. Then I explore the stage of todays&#39; understanding of the classical distance

Wil van Breugel, Carlos De Breuck, Adam Stanford, Huub Röttgering

Radio sources have traditionally provided convenient beacons for probing the early Universe. Hy Spinrad was among the first of the tenacious breed of observers who would attempt to obtain optical identifications and spectra of the faintest possible `radio galaxies&#39; to investigate the formation and evolution of galaxies at hy redshift. Modern telescopes a

T. M. Herbst, D. Thompson, R. Fockenbrock, H. -W. Rix

We report preliminary results of a deep near-infrared search for methane-absorbing brown dwarfs; almost five years after the discovery of Gl 229b, there are only a few confirmed examples of this type of object. New J band, wide-field images, combined with pre-existing R band observations, allow efficient identification of candidates by their extreme (R-J) co

P. Fosalba, E. Gaztanaga, E. Elizalde

The gravitational evolution of the cosmic one-point Probability Distribution Function (PDF) can be estimated using an analytic approximation that combines gravitational Perturbation Theory (PT) with the Edgeworth expansion around a Gaussian PDF. We present an alternative to the Edgeworth series based on an expansion around the Gamma PDF, which is more approp

D. P. Schneider, Gary J. Hill, X. Fan, L. W. Ramsey

This paper describes spectra of quasar candidates acquired during the commissioning phase of the Low-Resolution Spectrograph of the Hobby-Eberly Telescope. The objects were identified as possible quasars from multicolor image data from the Sloan Digital Sky Survey. The ten sources had typical r&#39; magnitudes of 19-20, except for one extremely red object wi

K. S. Cheng, Z. G. Dai

We here propose a two-step model for gamma-ray bursts (GRBs) associated with supernovae. In the first step, the core collapse of a star with mass $\ge 19M_\odot$ leads to a massive neutron star and a normal supernova, and subsequently hypercritical accretion of the neutron star from the supernova ejecta may give rise to a jet through neutrino annihilation an

M. E. J. Newman

This article gives a brief introduction to the mathematical modeling of large-scale biological evolution and extinction. We give three examples of simple models in this field: the coevolutionary avalanche model of Bak and Sneppen, the environmental stress model of Newman, and the increasing fitness model of Sibani, Schmidt, and Alstrom. We describe the featu

A. B. Larionov, W. Cassing, M. Effenberger, U. Mosel

The proton - charged pion correlated emission is studied in the reactions Au (1.06 AGeV) + Au, Ni (1.06 and 1.93 AGeV) + Ni and Ni (1.97 AGeV) + Cu within the BUU approach. The associated invariant mass distributions are shifted to smaller energies with respect to the free $Δ(1232)$ mass distribution due to kinematical reasons. We find that the existing and

A. P. Balachandran, S. Vaidya

In continuum physics, there are important topological aspects like instantons, theta-terms and the axial anomaly. Conventional lattice discretizations often have difficulties in treating one or the other of these aspects. In this paper, we develop discrete quantum field theories on fuzzy manifolds using noncommutative geometry. Basing ourselves on previous t

Piotr Bizoń

We prove existence of a countable family of spherically symmetric self-similar wave maps from 3+1 Minkowski spacetime into the 3-sphere. These maps can be viewed as excitations of the ground state wave map found previously by Shatah. The first excitation is particularly interesting in the context of the Cauchy problem since it plays the role of a critical so

Ikuo Ichinose, Keiichi Nagao

We generalize overlap fermion by Narayanan and Neuberger by introducing a hopping parameter t. This lattice fermion has desirable properties as the original overlap fermion. We expand &#34;Dirac&#34; operator of this fermion in powers of t. Higher-order terms of t are long-distance terms and this t-expansion is a kind of the hopping expansion. It is shown th

Valeriy P. Polulyakh

The nature of the physical space seems the most important subject in physics. A present paper proceeds from the assumption of physical reality of space contrary to the standard view of the space as a purely relational nonexistence - void. The space and its evolution are the primary sources of phenomena in Mega- and micro-worlds. Thus cosmology and particle p

R. F. Werner

In a recent paper [quant-ph/9910066], Arens and Varadarajan gave a characterization of what they call EPR-states on a bipartite composite quantum system. By definition, such states imply perfect correlation between suitable pairs of observables in the two subsystems, and the task is to determine all such correlated pairs for a given state. In this note the a

Klaus Jungmann

The electromagnetic interactions of electrons and muons can be described to very high accuracy within the framework of standard theory, in particular within the hydrogen-like muonium atom. Therefore precision measurements allow to test basic interactions in physics and to search for yet unknown forces. Accurate values for fundamental constants can be obtaine

W. Woelfli, W. Baltensperger

The astronomical theory of Milankovitch relates the changes of Earth&#39; past climate to variations in insolation caused by oscillations of the orbital parameters. However, this theory has problems to account for some major observed phenomena of the past few million years. Here, we present an alternative explanation for these phenomena. It is based on the i

Taras E. Panov

A quasitoric manifold is a smooth 2n-manifold M^{2n} with an action of the compact torus T^n such that the action is locally isomorphic to the standard action of T^n on C^n and the orbit space is diffeomorphic, as manifold with corners, to a simple polytope P^n. The name refers to the fact that topological and combinatorial properties of quasitoric manifolds

Carlo Rovelli

In fundamental physics, this has been the century of quantum mechanics and general relativity. It has also been the century of the long search for a conceptual framework capable of embracing the astonishing features of the world that have been revealed by these two ``first pieces of a conceptual revolution&#39;&#39;. I discuss the general requirements on the

Gh. Zet, M. C. Neacsu

A model of SU(2) gauge theory in the space-time $R\times S^3$ is constructed in terms of local gauge-invariant variables. A metric tensor $g_{μν}$ is defined starting with the components of the strength tensor $F_{μν}^k$ and of its dual $\widetilde{F}_{μν}^k$. It is shown that the components $g_{μν}$ determine the gauge field equations if some supplementary

George Sterman, Werner Vogelsang

Threshold resummation for factorizable cross sections in hadron-hadron collisions has a number of applications and extensions. We discuss factorization scale dependence, resummation at nonleading power in the moment variable, and the implications of resummation for power corrections in the hard momentum scale.

M. V. Galynsky, M. I. Levchuk

We have studied the reaction $ep \to ep γ$ in the kinematics corresponding to electron scattering at small angles and photon scattering at large angles, where proton bremsstrahlung dominates. The analysis is based on the direct evaluation method of the matrix elements in the so-called diagonal spin basis. The results of numerical calculations for electron be

Maria C. Neacsu

5D theory is an alternative model for understanding gravitational and electromagnetic interactions together. In this work we used the correspondence between 5D Einstein field equations with cosmological constant and the 4D Einstein equations with sources. We started with the principal fiber bundle P(M/F,U(1)) metric and studied the case when the gauge potent

Shinsuke Kawai, Jiro Soda

We propose novel structure formation scenarios based on a non-singular higher curvature cosmological model. The model is motivated by the $R^2$ coupling of a scalar field appearing in the string theory, and in our scenarios the universe has no beginning and no end. We give two examples with explicit parameter values which are consistent with present observat

Y. Naveh, K. K. Likharev

We have performed numerical modeling of dual-gate ballistic n-MOSFET&#39;s with channel length of the order of 10 nm, including the effects of quantum tunneling along the channel and through the gate oxide. Our analysis includes a self-consistent solution of the full (two-dimensional) electrostatic problem, with account of electric field penetration into the

Masashige Matsumoto, Manfred Sigrist

The electronic states near a surface or a domain wall in the p_x \pm i p_y -wave superconductor are studied. This state has been recently suggested as the superconducting state of Sr_2 Ru O_4. The p_x \pm i p_y-wave paring state breaks the time reversal symmetry and induces a magnetic field. The obtained temperature dependence of the magnetic field is consis

Y. Naveh

A short summary of the drift-diffusion-Langevin formalism for calculating finite-frequency shot noise in diffusive conductors is presented. Two new results are included in this presentation. First, we arrive at a simple (but accurate) phenomenological expression for the semiclassical distribution function of electrons in the presence of electron-electron sca

C. Giardina&#39;, R. Livi, A. Politi, M. Vassalli

We discuss the thermal conductivity of a chain of coupled rotators, showing that it is the first example of a 1d nonlinear lattice exhibiting normal transport properties in the absence of an on-site potential. Numerical estimates obtained by simulating a chain in contact with two thermal baths at different temperatures are found to be consistent with those o

Lieven M. K. Vandersypen, Matthias Steffen, Mark H. Sherwood, Costantino S. Yannoni

We report the experimental implementation of Grover&#39;s quantum search algorithm on a quantum computer with three quantum bits. The computer consists of molecules of $^{13}$C-labeled CHFBr$_2$, in which the three weakly coupled spin-1/2 nuclei behave as the bits and are initialized, manipulated, and read out using magnetic resonance techniques. This quantu

Ting-Wai Chiu

The role of R in the solutions of the Ginsparg-Wilson relation is discussed.

Carl Heiles

This is a revision. The revisions are minor. The new version of the catalog should be used in preference to the old. The most serious error in the older version was that $θ_diff$ was incorrect, being sometimes far too large, for Reiz and Franco entries; the correct values are all zero for that reference. We present an agglomeration of stellar polarization ca

Enke Wang, Ulrich Heinz

Starting from the Kubo formula we calculate the shear viscosity in hot phi**4 theory nonperturbatively by resumming ladders with a real-time version of the Bethe-Salpeter equation at finite temperature. In the weak coupling limit, the generalized Fluctuation-Dissipation Theorem is shown to decouple the Bethe-Salpeter equations for the different real-time com

Gui Lu Long, Yan Song Li, Wei Lin Zhang, Chang Cun Tu

It is found that Grover&#39;s quantum search algorithm is not robust against phase inversion and Hadmard transformation inaccuracies. Imperfect phase inversions and Hadmard-Walsh transformations in Grover&#39;s quantum search algorithm lead to reductions in the maximum probability of the marked state and affect the efficiency of the algorithm. even in the ab

S. Ansoldi, A. Aurilia, E. Spallucci

This paper suggests a new way to compute the path integral for simple quantum mechanical systems. The new algorithm originated from previous research in string theory. However, its essential simplicity is best illustrated in the case of a free non relativistic particle, discussed here, and can be appreciated by most students taking an introductory course in

Koen J. van Vlaenderen

The wave function $ψ$ is interpreted as charge density, or charge distribution, at each point in space. This is a physical interpretation of $ψ$. The notion of speed can be associated with $ψ$, which leads to the concept of conduction currents and (displacement) convection currents. The charge distribution is the origin of electrical and mechanical sources,

Rebecca B. Hoyle

The Cross-Newell equations for hexagons and triangles are derived for general real gradient systems, and are found to be in flux-divergence form. Specific examples of complex governing equations that give rise to hexagons and triangles and which have Lyapunov functionals are also considered, and explicit forms of the Cross-Newell equations are found in these

A. Misra, D. S. Koltun

One-loop corrections at the two-nucleon level to Pion Double Charge exchange (DCX) scattering off a nuclear target at threshold, are calculated within the framework of Heavy Baryon Chiral Perturbation Theory (HBChPT). An estimate for the (2-nucleon) 1-loop correction is obtained in the static limit and using an impulse approximation. We find a small (1.6%) i

O. M. Kiselev

The dromion of the Davey-Stewartson-1 equation is studied under perturbation on the large time.

L. R. U. Manssur

By performing the canonical quantization of the Abelian Chern-Simons model on the light-front (as suggested by Dirac), we clarify some controversies appearing in recent papers that discuss the relation between the existence of excitations carrying fractional spin and statistics (anyons) and this model. Properties of the Chern-Simons model on the light-front

Barry R. Holstein

A range of issues in the field of hyperon physics is presented, together with an assessment of where important challenges remain.

Takanori Fujiwara, Hiroshi Suzuki, Ke Wu

The chiral anomaly in lattice abelian gauge theory is investigated by applying the geometric and topological method in noncommutative differential geometry(NCDG). A new kind of double complex and descent equation are proposed on infinite hypercubic lattice in arbitrary even dimensional Euclidean space, in the framework of NCDG. Using the general solutions to

Greg Landsberg

We present recent results on searches for non-SUSY new physics at the CDF and D0 Collaborations in the 1992-1996 Fermilab Tevatron run. While no compelling evidence for existence of new physics was found, the Tevatron data have excluded a significant region of the theoretically allowed phase space for a variety of non-SUSY extensions of the Standard Model. T

Milan M. Cirkovic, Nick Bostrom

The influence of recent detections of a finite vacuum energy (&#34;cosmological constant&#34;) on our formulation of anthropic conjectures, particularly the so-called Final Anthropic Principle is investigated. It is shown that non-zero vacuum energy implies the onset of a quasi-exponential expansion of our causally connected domain (&#34;the universe&#34;) a

Jeffrey L. Billeter, Robert A. Pelcovits

We performed Monte Carlo simulations of systems of wedge-shaped objects formed from Gay-Berne ellipsoids joined to Lennard-Jones spheres. We studied two different wedge shapes, one more asymmetric than the other. The bend and splay flexoelectric coefficients were measured in the isotropic and smectic phases using linear response theory, and found to be negli

S. Lubeck, N. Rajewsky, D. E. Wolf

The Bak-Tang-Wiesenfeld (BTW) sandpile model is a cellular automaton which has been intensively studied during the last years as a paradigm for self-organized criticality. In this paper, we reconsider a deterministic version of the BTW model introduced by Wiesenfeld, Theiler and McNamara, where sand grains are added always to one fixed site on the square lat

Jeroen van den Brink, Giniyat Khaliullin, Daniel Khomskii

An explanation is given for the charge order, orbital order and insulating state observed in half-doped manganese oxides, such as Nd$_{1/2}$Sr$_{1/2}$MnO$_{3}$. The competition between the kinetic energy of the electrons and the magnetic exchange energy drives the formation of effectively one-dimensional ferromagnetic zig-zag chains. Due to a topological pha

Rebecca B. Hoyle, Anita Mehta

We formulate a continuum model for aeolian sand ripples consisting of two species of grains: a lower layer of relatively immobile clusters, with an upper layer of highly mobile grains moving on top. We predict analytically the ripple wavelength, initial ripple growth rate and threshold saltation flux for ripple formation. Numerical simulations show the evolu

C. Reichhardt, C. J. Olson, Franco Nori

We investigate the pinning and driven dynamics of vortices interacting with twin boundaries using large scale molecular dynamics simulations on samples with near one million pinning sites. For low applied driving forces, the vortex lattice orients itself parallel to the twin boundary and we observe the creation of a flux gradient and vortex free region near

S. K. Saha, B. S. Nagabhushana, A. V. Ananth, P. Venkatakrishnan

An experiment for the speckle reconstruction of solar features was developed for observing the partial eclipse of the sun as viewed from Bangalore on October 24, 1995. No data could be obtained because of cloudy sky but the experimental details are described.

L. M. Boone, J. S. Bullock, J. R. Primack, D. A. Williams

This paper represents a step toward constraining galaxy formation models via TeV gamm a ray observations. We use semi-analytic models of galaxy formation to predict a spectral distribution for the intergalactic infrared photon field, which in turn yields information about the absorption of TeV gamma rays from extra-galactic sources. By making predictions for

V. Antonuccio-Delogu, U. Becciani, A. Pagliaro

Using the results of a high mass resolution ($256^{3}$ particles) N-body simulation of a cluster-forming region, we study the statistic $σ_{v}-M$ for low mass halos (${\rm M} < 10^{12} {\rm M}_{\sun}$), and we compare it with three theoretical models. At the final redshift halos are well described by the Truncated Isothermal Sphere model recently introduced

Andrei Mikhailov

Supergravity on $AdS_3\times S^3\times {\bf T}^4$ has a dual description as a conformal sigma-model with the target space being the moduli space of instantons on the noncommutative torus. We derive the precise relation between the parameters of this noncommutative torus and the parameters of the near-horizon geometry. We show that the low energy dynamics of

T. Senthil, Matthew P. A. Fisher

We develop a new theoretical framework for describing and analyzing exotic phases of strongly correlated electrons which support excitations with fractional quantum numbers. Starting with a class of microscopic models believed to capture much of the essential physics of the cuprate superconductors, we derive a new gauge theory - based upon a {\it discrete} I

S. Barabash, D. Stroud

Erratum: In our paper, we show that the spectral representation for isotropic two-component composites also applies to uniaxial polycrystals. We have learned that this result was, in fact, first conjectured by G.W. Milton. While our derivation is more detailed, our result for the spectral function is the same as Milton&#39;s. We very much regret not having b

N. Gurappa, Prasanta K. Panigrahi

The algebraic structure and the relationships between the eigenspaces of the Calogero-Sutherland model (CSM) and the Sutherland model (SM) on a circle are investigated through the Cherednik operators. We find an exact connection between the simultaneous non-symmetric eigenfunctions of the $A_{N-1}$ Cherednik operators, from which the eigenfunctions of the CS

Zoran Konkoli, Henrik Johannesson

We study a two-species reaction-diffusion model where A+A->0, A+B->0 and B+B->0, with annihilation rates lambda0, delta0 > lambda0 and lambda0, respectively. The initial particle configuration is taken to be randomly mixed with mean densities nA(0) > nB(0), and with the two species A and B diffusing with the same diffusion constant. A field-theoretic renorma

Andrea Cavagna

In the context of the energy landscape description of supercooled liquids, we propose an explanation for the different behaviour of fragile and strong liquids. Above the Goldstein crossover temperature Tx, diffusion is interpreted as a motion in the phase space among unstable stationary points of the potential energy, that is among saddles. In this way two m

R. Lieu, M. Bonamente, J. P. D. Mittaz, F. Durret

The EUV excess emission from the clusters A2199 and A1795 remains an unexplained astrophysical phenomenon. There has been many unsuccessful attempts to `trivialize&#39; the findings. In this Letter we present direct evidence to prove that the most recent of such attempts, which attributes the detected signals to a background non-uniformity effect, is likewis

Mark A. Pankov

The book is devoted to study so-called irregular subsets of the Grassmannian manifold $G^{n}_{k}(V)$ (this class of sets was introduced by author). In the previous variant of the book we restrict ourself only to the case when $V$ is an $n$-dimensional vector space under the field $R$. Now we consider irregular subsets of $G^{n}_{k}(V)$, where $V$ is an $n$-d

Subir Sachdev, Matthias Vojta

It was argued many years ago that translational symmetry breaking due to the appearance of spin-Peierls ordering (or bond-charge stripe order) is a fundamental property of the quantum paramagnetic states of a large class of square lattice antiferromagnets. Recently, such states were shown to be a convenient point of departure for studying translational symme

S. Y. Sazonov, R. A. Sunyaev

The frequency distribution of photons in frequency that results from single Compton scattering of monochromatic radiation on thermal electrons is derived in the mildly relativistic limit. Algebraic expressions are given for (1) the photon redistribution function, K(nu,Omega -> nu&#39;,Omega&#39;), and (2) the spectrum produced in the case of isotropic incide

Yu Shi

For a Bose condensate in a double-well potential or with two Josephson-coupled internal states, the condensate wavefunction is a superposition. Here we consider coupling two such Bose condensates, and suggest the existence of a joint condensate wavefunction, which is in general a superposition of all products of the bases condensate wavefunctions of the two

R. A. Blythe, M. R. Evans, F. Colaiori, F. H. L. Essler

We study the partially asymmetric exclusion process with open boundaries. We generalise the matrix approach previously used to solve the special case of total asymmetry and derive exact expressions for the partition sum and currents valid for all values of the asymmetry parameter q. Due to the relationship between the matrix algebra and the q-deformed quantu

M. Czakon, J. Gluza, M. Zralek

In spite of the general belief that neutrinos are Majorana particles, their character should be revealed experimentally. We begin by discussing why it is so difficult in terrestrial experiments. If neutrinos are Majorana particles, the first signal should come from neutrinoless double $β$ decay. Still the search for such a decay of various nuclei is negative