March 1996 arXiv papers — page 3

Mary Alberg, Ernest M. Henley

We propose a flavor asymmetry in the light quark sea of $Σ^{\pm}$, which can be measured in Drell-Yan experiments using charged hyperon beams on proton and deuteron targets. Such a measurement would help to reinforce the presence of pseudoscalar mesons in a quark model of baryons.

Christoph Greub, Tobias Hurth, D. Wyler

We present in detail the calculation of the $O(\a_s)$ virtual corrections to the matrix element for $b \to s \g$. Besides the one-loop virtual corrections of the electromagnetic and color dipole operators $O_7$ and $O_8$, we include the important two-loop contribution of the four-Fermi operator $O_2$. By applying the Mellin-Barnes representation to certain i

M. Beneke, I. Z. Rothstein

We analyze charmonium and bottomonium production at fixed target experiments. We find that inclusion of color octet production channels removes large discrepancies between experiment and the predictions of the color singlet model for the total production cross section. Furthermore, including octet contributions accounts for the observed direct to total $J/ψ$

D. H. Saxon

Particle Physics in International Collaboration. Talk given at Kolloquiumstag ``125 Jahre Teilchenphysik in Aachen", October 1995

S. Carlip

Although we know that black holes are characterized by a temperature and an entropy, we do not yet have a satisfactory microscopic ``statistical mechanical'' explanation for black hole thermodynamics. I describe a new approach that attributes the thermodynamic properties to ``would-be gauge'' degrees of freedom that become dynamical on the ho

F. Ya. Khalili, Yu. Levin

Quantum noise is an important issue for advanced LIGO. Although it is in principle possible to beat the Standard Quantum Limit (SQL), no practical recipe has been found yet. This paper dicusses quantum noise in the context of speedmeter-a devise monitoring the speed of the testmass. The scheme proposed to overcome SQL in this case might be more practical tha

Thomas Leness

The wall-crossing formula for Donaldson invariants of smooth, simply connected four manifolds with $b^+=1$ is shown to be a topological invariant of the manifold for reducible connections with two or fewer singular points. The explicit formulas derived agree with those of Ellingsrud and Gottische and Friedman and Qin for algebraic manifolds.

Eugene Lerman, Eckhard Meinrenken, Sue Tolman, Chris Woodward

In this paper we extend the results of Kirwan et alii on convexity properties of the moment map for Hamiltonian group actions, and on the connectedness of the fibers of the moment map, to the case of non-compact orbifolds. Our motivation is twofold. First, the category of orbifolds is important in symplectic geometry because, generically, the symplectic quot

V. E. Kravtsov

The statistics of energy levels of electrons in a random potential is considered in the critical energy window near the mobility edge. It is shown that the multifractality of critical wave functions results in the violation of the normalization sum rule in the thermodynamic limit and leads to the quasi-Poisson linear term in the level number variance. The sl

Naomichi Hatano, David R. Nelson

We study the localization transitions which arise in both one and two dimensions when quantum mechanical particles described by a random Schrödinger equation are subjected to a constant imaginary vector potential. A path-integral formulation relates the transition to flux lines depinned from columnar defects by a transverse magnetic field in superconductors.

Daisy M. Luz, Raimundo R. dos Santos

We study the effects of bond-charge interaction (or correlated hopping) on the properties of the extended ({\it i.e.,} with both on-site ($U$) and nearest-neighbor ($V$) repulsions) Hubbard model in one dimension at half-filling. Energy gaps and correlation functions are calculated by Lanczos diagonalization on finite systems. We find that, irrespective of t

P. Pieri, S. Daul, D. Baeriswyl, M. Dzierzawa

A single-band Hubbard model with nearest and next-nearest neighbour hopping is studied for $d=1$, 2, 3, using both analytical and numerical techniques. In one dimension, saturated ferromagnetism is found above a critical value of $U$ for a band structure with two minima and for small and intermediate densities. This is an extension of a scenario recently pro

S. Ramasesha, Swapan K. Pati, H. R. Krishnamurthy, Z. Shuai

We extend the density matrix renormalization group method to exploit Parity, $C_2$ (rotation by $π$) and electron-hole symmtries of model Hamiltonians. We demonstrate the power of this method by obtaining the lowest energy states in all the eight symmetry subspaces of Hubbard chains with upto 50 sites. The ground-state energy, optical gap and spin gap of reg

T. H. Stoof, Yu. V. Nazarov

We have extended the circuit theory of Andreev conductance [Phys.~Rev.~Lett. {\bf 73}, 1420 (1994)] to diffusive superconducting hybrid structures that contain an Aharonov-Bohm ring. The electrostatic potential distribution in the system is predicted to be flux-dependent with a period of the superconducting flux quantum $Φ_{0}=h/2e$. When at least one tunnel

A. Kashuba, Ar. Abanov, V. L. Pokrovsky

In the ordered phase of 2D XY ferromagnet the dipolar interaction between spins induces a strong, relevant interaction between spin-waves. We study quasi-excitations of the interacting spin-wave 'liquid' in the long wavelength limit. We employ the Janssen-De-Dominicis method for classical Langevin equation to find the transformation of the spin-wave

T. Garel, H. Orland

A disorder-dependent Gaussian variational approach is applied to the problem of a $d$ dimensional polymer chain in a random medium (or potential). Two classes of variational solutions are obtained. For $d<2$, these two classes may be interpreted as domain and domain wall. The critical exponent $ν$ describing the polymer width is $ν={1\over (4-d)}$ (domain so

Peter Kopietz, Guillermo E. Castilla

We develop a systematic method to treat the effect of non-linearity in the energy dispersion on the usual bosonization result for the single-particle Green&#39;s function of fermions in arbitrary dimension. The leading corrections due to the quadratic term in the energy dispersion are explicitly calculated. In the Chern-Simons theory for half-filled quantum

R. T. Boreiko, A. L. Betz

We have used a laser heterodyne spectrometer to resolve the emission line profile of the 63 micron 3P1 - 3P2 fine-structure transition of O I at two locations in M42. Comparison of the peak antenna temperature with that of the 158 micron C II fine-structure line shows that the gas kinetic temperature in the photodissociation region near theta1C is 175 - 220

S. W. Hawking, C. J. Hunter

This paper generalizes earlier work on Hamiltonian boundary terms by omitting the requirement that the spacelike hypersurfaces $Σ_t$ intersect the timelike boundary $\cal B$ orthogonally. The expressions for the action and Hamiltonian are calculated and the required subtraction of a background contribution is discussed. The new features of a Hamiltonian form

Ali Mostafazadeh

The general features of the degeneracy structure of ($p=2$) parasupersymmetric quantum mechanics are employed to yield a classification scheme for the form of the parasupersymmetric Hamiltonians. The method is applied to parasupersymmetric systems whose Hamiltonian is the square root of a forth order polynomial in the generators of the parasupersymmetry. The

A. Y. Potekhin

Transport properties of degenerate relativistic electrons along quantizing magnetic fields in neutron star crusts are considered. A kinetic equation is derived for the spin polarization density matrix of electrons. Its solution does not depend on the choice of basic electron wave functions unlike previous solutions of the traditional kinetic equation for the

Jae-weon Lee, In-guy Koh

We study fermion reflection at a phase wave which is formed during a bubble collision in a first order phase transition. We calculate the reflection and the transmission coefficients by solving the Dirac equation with the phase wave background. Using the results we analyze the damping and the velocity of the wave.

Eduardo Fradkin, Steven Kivelson

We investigate the problem of the superuniversality of the phase transition between different quantum Hall plateaus. We construct a set of models which give a qualitative description of this transition in a pure system of interacting charged particles. One of the models is manifestly invariant under both Duality and Periodic shifts of the statistical angle a

Giuseppe Tormen, Francois R. Bouchet, Simon D. M. White

(Shortened) We use N-body simulations to investigate the structure and dynamical evolution of dark matter halos in galaxy clusters. Our sample consists of nine massive halos from an EdS universe with scale free power spectrum and n = -1. Halos are resolved by ~20000 particles each, with a dynamical resolution of 20-25 kpc. Large scale tidal fields are includ

U. Lisenfeld, H. J. Voelk, C. Xu

This paper investigates the physical reasons for the existence, the tightness and the near universality of the FIR/radio correlation for late-type field galaxies. We develop theoretical models for the radio and far-infrared (FIR) emission of normal galaxies and study the influence of their main parameters on the ratio of the two emissions. In addition, data

Xiang-Qian Luo

I derive the equation of motion in molecular dynamics for doing full lattice QCD simulations with clover quarks. The even-odd preconditioning technique, expected to significantly reduce the computational effort, is further developed for the simulations.

M. Dakna, L. Knoll, D. -G. Welsch

Using coherent phase states, parameterized phase state distributions for a single-mode radiation field are introduced and their integral relation to the phase-parameterized field-strength distributions is studied. The integral kernel is evaluated and the problem of direct sampling of the coherent phase state distributions using balanced homodyne detection is

J. Blümlein, N. Kochelev

The twist-2 contributions to the polarized structure functions in deep inelastic lepton--hadron scattering are calculated including the exchange of weak bosons and using both the operator product expansion and the covariant parton model. A new relation between two structure functions leading to a sequence of new sum rules is found. The light quark mass corre

Christof Zalka

We show that the time evolution of the wave function of a quantum mechanical many particle system can be implemented very efficiently on a quantum computer. The computational cost of such a simulation is comparable to the cost of a conventional simulation of the corresponding classical system. We then sketch how results of interest, like the energy spectrum

Elchanan Almoznino, Noah Brosch

We study star-formation-inducing mechanisms in galaxies through multi- wavelength measurements of a sample of dwarf galaxies in the Virgo cluster described in paper I. Our main goal is to test how star formation inducing mechanisms depend on several parameters of the galaxies, such as morphological type and hydrogen content. We derive the star formation rate

David R. Morrison, Cumrun Vafa

We continue our study of compactifications of F-theory on Calabi--Yau threefolds. We gain more insight into F-theory duals of heterotic strings and provide a recipe for building F-theory duals for arbitrary heterotic compactifications on elliptically fibered manifolds. As a byproduct we find that string/string duality in six dimensions gets mapped to fiber/b

Kiyoshi Okuyama, Hiroshi Suzuki

When the path integral method of anomaly evaluation is applied to chiral gauge theories, two different types of gauge anomaly, i.e., the consistent form and the covariant form, appear depending on the regularization scheme for the Jacobian factor. We clarify the relation between the regularization scheme and the Pauli--Villars--Gupta (PVG) type Lagrangian le

Pavel Etingof, Konstantin Styrkas

In this paper we construct examples of commutative rings of difference operators with matrix coefficients from representation theory of quantum groups, generalizing the results of our previous paper to the $q$-deformed case. A generalized Baker-Akhiezer function $Ψ$ is realized as a matrix character of a Verma module and is a common eigenfunction for a commu

Moti Gitik, Saharon Shelah

We construct two universes V_1, V_2 satisfying the following: GCH below \aleph_ω, 2^{\aleph_ω} = \aleph_{ω+2} and the topological density of the space 2^{\aleph_ω} with \aleph_0 box product topology is \aleph_{ω+1} in V_1 and \aleph_{ω+2} in V_2. Further related results are discussed as well.

J. M. F. Labastida, M. Mariño

We present an equivariant extension of the Thom form with respect to a vector field action, in the framework of the Mathai-Quillen formalism. The associated Topological Quantum Field Theories correspond to twisted $N=2$ supersymmetric theories with a central charge. We analyze in detail two different cases: topological sigma models and non-abelian monopoles

Ioannis Giannakis

We implement the O(d,d,Z) transformations of T-duality as automorphisms of the operator algebras of Conformal Field Theories. This extends these transformations to arbitrary field configurations in the deformation class.

Gungwon Kang

Complex frequency modes occur for a scalar field near a rapidly rotating star {\it with ergoregion but no event horizon}. Such complex frequency modes must be included in the quantization of the field. As a model for this system, we have investigated a real scalar field with mass $μ$ in a one-dimensional square-well potential. If the depth of the potential i

Phil E. Gibbs

In this sequel to my previous paper, &#34;Is String Theory in Knots?&#34; I explore ways of constructing symmetries through an algebraic stepping process using knotted graphs. The hope is that this may lead to an algebraic formulation of string theory. In the conclusion I speculate that the stepping process is a form of quantisation for which the most genera

E. Calzetta, B-L. Hu

We explore how the existence of a field with a heavy mass influences the low energy dynamics of a quantum field with a light mass by expounding the stochastic characters of their interactions which take on the form of fluctuations in the number of (heavy field) particles created at the threshold, and dissipation in the dynamics of the light fields, arising f

J. M. Maillard, C. M. Viallet

We analyze free-fermion conditions on vertex models. We show --by examining examples of vertex models on square, triangular, and cubic lattices-- how they amount to degeneration conditions for known symmetries of the Boltzmann weights, and propose a general scheme for such a process in two and more dimensions.

Akifumi Sako

It is known that if gauge conditions have Gribov zero modes, then topological symmetry is broken. In this paper we apply it to topological gravity in dimension $n \geq 3$. Our choice of the gauge condition for conformal invariance is $R+α=0$ , where $R$ is the Ricci scalar curvature. We find when $α\neq 0$, topological symmetry is not broken, but when $α=0$

A. Delfino, Jishnu Dey, Mira Dey, M. Malheiro

The models of translationally invariant infinite nuclear matter in the relativistic mean field models are very interesting and simple, since the nucleon can connect only to a constant vector and scalar meson field. Can one connect these to the complicated phase transitions of QCD ? For an affirmative answer to this question, one must consider models where th

Horace W. Crater, Chun Wa Wong, Cheuk-Yin Wong

We examine the relation between two approaches to the quantum relativistic two-body problem: (1) the Breit equation, and (2) the two-body Dirac equations derived from constraint dynamics. The Breit equation is known to be pathological when singularities appear at finite separations $r$ in the reduced set of coupled equations for attractive potentials even wh

Raimo Vuopionperä

This thesis concerns the testing of the SM and its extensions in e+e- collisions, the main emphasis being on neutrino physics (abridged abstract).

V. Driesen, W. Hollik, A. Kraft

The effect of virtual electroweak corrections to $e^+e^- \rightarrow t \bar{t}$ and the contribution of the radiation processes $e^+e^- \rightarrow t\bar{t}Z, t\bar{t}H$ to the inclusive top pair production cross section and forward-backward asymmetry are discussed in the high energy regime.

Tamas G. Kovacs

We propose a mechanism that can create a mass gap in the SU(2) chiral spin model at arbitrarily small temperatures. We give a sufficient condition for the mass gap to be non-zero in terms of the behaviour of an external Z(2) flux introduced by twisted boundary conditions. This condition in turn is transformed into an effective dual Ising model with an extern

Andre&#39; Lukas, Rudolf Poppe

We analyze the quantum cosmology of the simplest pre--big--bang model without dilaton potential. In addition to the minisuperspace variables we include inhomogeneous dilaton fluctuations and determine their wave function on a semiclassical background. This wave function is used to calculate the reduced density matrix and to find criteria for the loss of deco

C. J. Fewster, A. Higuchi, C. G. Wells

We study the classical and quantum theory of a class of nonlinear differential equations on chronology violating spacetime models in which space consists of finitely many discrete points. Classically, in the linear and weakly nonlinear regimes (for generic choices of parameters) we prove existence and uniqueness of solutions corresponding to initial data spe

Eduard Prugovecki

The physical concept of locality is first analyzed in the special relativistic quantum regime, and compared with that of microcausality and the local commutativity of quantum fields. Its extrapolation to quantum general relativity on quantum bundles over curved spacetime is then described. It is shown that the resulting formulation of quantum-geometric local

R. Rieth, G. Schäfer

The Wilson approximate dynamics and the Einstein dynamics are compared for binary systems. At the second post-Newtonian approximation, genuine two-body aspects are found to differ by up to 114\%. In the regime of a formal innermost stable circular orbit (ISCO) the both dynamics differ by up to 7\%.

S. Krasnikov

Paradoxes that can supposedly occur if a time machine is created are discussed. It is shown that the existence of trajectories of ``multiplicity zero&#39;&#39; (i.e. trajectories that describe a ball hitting its younger self so that the latter cannot fall into the time machine) is not paradoxical by itself. This {\em apparent paradox} can be resolved (at lea

M. Tsuda, T. Shirafuji

We consider the supersymmetry (SUSY) transformations in the chiral Lagrangian for $N = 1$ supergravity (SUGRA) with the complex tetrad following the method used in the usual $N = 1$ SUGRA, and present the explicit form of the SUSY trasformations in the first-order form. The SUSY transformations are generated by two independent Majorana spinor parameters, whi

K. Ramachandran, Akhil Ranjan

In this note we shall show that the sectional curvature of a harmonic manifold is bounded on both sides. In fact we shall give a pinching constant for all harmonic manifolds. We shall use the imbedding theorem for harmonic manifolds proved by Z.I.Szabo and the description of screw lines in hilbert spaces to prove the result.

M. V. N. Murthy, R. K. Bhaduri, Diptiman Sen

We construct a new many-body Hamiltonian with two- and three-body interactions in two space dimensions and obtain its exact many-body ground state for an arbitrary number of particles. This ground state has a novel pairwise correlation. A class of exact solutions for the excited states is also found. These excited states display an energy spectrum similar to

Kent Bækgaard Lauritsen, Stefano Zapperi, H. Eugene Stanley

We explore in the mean-field approximation the robustness with respect to dissipation of self-organized criticality in sandpile models. To this end, we generalize a recently introduced self-organized branching process, and show that the model self-organizes not into a critical state but rather into a subcritical state: when dissipation is present, the dynami

G. Chiappe, J. A. Vergés, E. Louis

Persistent currents in mesoscopic metallic rings induced by static magnetic fields are investigated by means of a Hamiltonian which incorporates diagonal disorder and the electron-electron interaction through a Hubbard term ($U$). Correlations are included up to second order perturbation theory which is shown to work accurately for $U$ of the order of the ho

M. E. Zhitomirsky, Kazuo Ueda

We propose a new type of magnetically disordered ground state for a frustrated quantum antiferromagnet. This disordered state is an array of spin singlets spontaneously formed on four spin plaquettes. Both perturbation results and bond-operator calculations show that this phase has lower energy than the columnar dimer state. Analysis of available numerical d

M. Apostol

The thermodynamical potential for dilute solutions is rederived, generalized and applied to defects in solids. It is shown that there are always defects in solids, i.e. there is no perfect solid at any finite temperature. Apart from the temperature- dependent concentration of defects, another case is presented, where the defect concentration does not depend

E. Ben-Naim, J. B. Knight, E. R. Nowak

Experimental studies show that the density of a vibrated granular material evolves from a low density initial state into a higher density final steady state. The relaxation towards the final density value follows an inverse logarithmic law. We propose a simple stochastic adsorption-desorption process which captures the essential mechanism underlying this rem

M. Apostol

It is shown that the C60-fullerene anion has a hydrogen-like spectrum.

P. J. Forrester

The Dyson Brownian motion model for transistions to the CUE is considered. For initial eigenvalue probability density functions corresponding to the COE and CSE, the density-density correlation function between an eigenvalue at position lambda&#39; initially (tau = 0) and an eigenvalue at position lambda for general tau, is calculated. Theoretical prediction

M. Apostol

New, approximate, two-electron wavefunctions are introduced for the two-electron atoms (cations), which account remarkably well for the ground-state energies and the lowest-excxited states (where available). A new scheme of electronic configurations is also proposed for the multi-electron atoms.

V. Celebonovic

This is a review of the main physical ideas and examples of applicability in astrophysics and pure physics of a semiclassical theory of dense matter proposed by Pavle Savic and Radivoje Kasanin in the early sixties. A hypothesis, advanced by Savic with the aim of solving the problem of the origin of rotation of celestical bodies,will also be discussed. The p

Feng Ma, Bingrong Xie

When a spinning-down neutron star undergoes a phase transition that produces quark matter in its core, a Super-Giant Glitch of the order $Δ Ω/Ω\sim 0.3$ occurs on time scales from 0.05 seconds to a few minutes. The energy released is about $10^{52}$ ergs and can account for Gamma Ray Bursts at cosmological distances. The estimated burst frequency, $10^{-6}$

C. Rodrigo-Blanco, J. Pérez-Mercader

Rotation curves of spiral galaxies are known with reasonable precision for a large number of galaxies with similar morphologies. The data implies that non-Keplerian fall--off is seen. This implies that (i) large amounts of dark matter must exist at galactic scales or (ii) that Newtonian gravity must somehow be corrected. We present a method for inverting the

J. W. Moffat

The gravitational wave solutions obtained from a perturbation about conformally flat backgrounds in Einstein gravity are investigated. A perturbation theory analysis of the Lesame, Ellis and Dunsby results, based on a covariant approach, shows that for gravitational waves interacting with irrotational dust, the equations are linearization unstable. The gravi

Esteban A. Calzetta, Alejandra Kandus

We present an analytical method to extract observational predictions about non linear evolution of perturbations in a Tolman Universe. We assume no a priori profile for them. We solve perturbatively a Hamilton - Jacobi equation for a timelike geodesic and obtain the null one as a limiting case in two situations: for an observer located in the center of symme

S. Hosono, B. H. Lian, S. -T. Yau

In this note, we give a list of Calabi-Yau hypersurfaces in weighted projective 4-spaces with the property that a hypersurface contains naturally a pencil of K3 variety. For completeness we also obtain a similar list in the case K3 hypersurfaces in weighted projective 3-spaces. The first list significantly enlarges the list of K3-fibrations of \KlemmLercheMa

Elchanan Almoznino, Noah Brosch

We selected samples of late-type dwarf galaxies in the Virgo cluster with HI information. The galaxies were observed at the Wise-Observatory using several broad-band and H$α$ bandpasses. UV measurements were carried out with the IUE Observatory from VILSPA, and with the FAUST shuttle-borne UV telescope. We describe our observations in detail, paying particul

Fedor Bogomolov, Tony Pantev

The purpose of this note is to give a simple proof of the following theorem: Let $X$ be a normal projective variety over an algebraically closed field $k$, $\op{char} k = 0$ and let $D \subset X$ be a proper closed subvariety of $X$. Then there exist a smooth projective variety $M$, a strict normal crossings divisor $R \subset M$ and a birational morphism $f

S. Meljanac, M. Milekovic, A. Perica

Using deformed Green&#39;s oscillators and Green&#39;s Ansatz,we construct a multiparameter interpolation between para-Bose and para-Fermi statistics of a given order. When the interpolating parameters $q_{ij}$ satisfy $|q_{ij}|<1 (|q_{ij}|= 1)$, the interpolation statistics is &#34;infinite quon&#34;-like (anyon-like).The proposed interpolation does not con

Jim Stasheff

The ``classical BRST construction&#39;&#39; as developed by Batalin-Fradkin-Vilkovisky is a homological construction for the reduction of the Poisson algebra $P = C^\infty (W)$ of smooth functions on a Poisson manifold $W$ by the ideal $I$ of functions which vanish on a constraint locus. This ideal is called first class if $I$ is closed under the Poisson bra

M. Apostol

The stability of metallic clusters of sodium (Na) in the octahedral cages of Na-doped fullerites Na6C60 and Na11C60 is discussed within a Thomas-Fermi model. It is shown that the tetrahedral Na4-cluster in Na6C60 has an electric charge of cca. +2.7 (in electron charge units), while the body-centered cubic Na9-cluster in Na11C60 is almost electrically neutral

Michael Christ

Hypoellipticity in Gevrey classes $G^s$ is characterized for a simple family of sums of squares of vector fields satisfying the bracket hypothesis, with analytic coefficients. It is shown that hypoellipticity holds if and only if $s$ is greater than or equal to an optimal exponent that may take on any rational value.

Kenneth Intriligator, Scott Thomas

Supersymmetry breaking by the quantum deformation of a classical moduli space is considered. A simple, non-chiral, renormalizable model is presented to illustrate this mechanism. The well known, chiral, $SU(3) \times SU(2)$ model and its generalizations are shown to break supersymmetry by this mechanism in the limit $Λ_2 \gg Λ_3$. Other supersymmetry breakin

Kei-Ichi Kondo

We propose the gauged Thirring model as a natural gauge-invariant generalization of the Thirring model, four-fermion interaction of current-current type. In the strong gauge-coupling limit, the gauged Thirring model reduces to the recently proposed reformulation of the Thirring model as a gauge theory. Especially, we pay attention to the effect coming from t

Andro Barnaveli, Merab Gogberashvili

We consider interactions of fermions with the domain wall bubbles produced during the first order phase transitions. New exact solution of Dirac equations and reflection coefficient are obtained.

Qing-Jun Liu

Multi-particle transverse energy correlation(MTEC) functions are proposed to study minijet production in high energy proton-antiproton collisions. Obtainable with both the D0 and the CDF detector, the high-order MTEC functions are shown to be sensitive probes of jet internal structure as well as promising observables of detecting minijet production in $\sqrt

Yuri N. Obukhov, Sergey I. Tertychniy

A closed explicit representation of the vacuum Einstein equations in terms of components of curvature 2-forms is given. The discussion is restricted to the case of non-vanishing cubic invariant of conformal curvature spinor. The complete set of algebraic and differential identities connecting particular equations is presented and their consistency conditions

K. Ramachandran, Akhil Ranjan

We show that noncompact simply connected harmonic manifolds with volume density $Θ_{p}(r) =\sinh ^{n-1} r$ is isometric to the real hyperbolic space and noncompact simply connected Kähler harmonic manifold with volume density $Θ_{p}(r) =\sinh ^{2n-1} r \cosh r$ is isometric to the complex hyperbolic space. A similar result is also proved for Quaternionic Käh

Rudolf Podgornik

A self-interacting polymer can undergo an orientational ordering transition, depending on the magnitude of the nematic interaction. The effect of embedding such a polymer into a flexible surface on this transition is studied on the mean-field level. Renormalized values of the elastic constants of the ``dressed&#39;&#39; surface are derived as functions of th

Makoto Kuwabara, Akira Terai, Yoshiyuki Ono

The structure of moving nonlinear excitations in one-dimensional electron-phonon systems is studied semi-phenomenologically by using an effective action in which the width of the nonlinear excitation is treated as a dynamical variable. The effective action can be derived from Su, Schrieffer and Heeger&#39;s model or its continuum version proposed by Takayama

Dan Abramovich, Johan de Jong

We provide a new proof of the following result: Let $X$ be a variety of finite type over an algebraically closed field $k$ of characteristic 0, let $Z\subset X$ be a proper closed subset. There exists a modification $f:X_1 \rar X$, such that $X_1$ is a quasi-projective nonsingular variety and $Z_1 = f^{-1}(Z)_\red$ is a strict divisor of normal crossings. Ne

Yi-Zhi Huang, James Lepowsky

In a program to formulate and develop two-dimensional conformal field theory in the framework of algebraic geometry, Beilinson and Drinfeld have recently given a notion of ``chiral algebra&#39;&#39; in terms of D-modules on algebraic curves. This definition consists of a ``skew-symmetry&#39;&#39; relation and a ``Jacobi identity&#39;&#39; relation in a categ

D. K. Hong, Y. Kim, S. -J. Sin

We perform the renormalization group analysis on the dynamical symmetry breaking under strong external magnetic field, studied recently by Gusynin, Miransky and Shovkovy. We find that any attractive four-Fermi interaction becomes strong in the low energy, thus leading to dynamical symmetry breaking. When the four-Fermi interaction is absent, the $β$-function

Vipul Periwal, Øyvind Tafjord

It is shown that there are logarithmic operators in D-brane backgrounds that lead to infrared divergences in open string loop amplitudes. These divergences can be cancelled by changing the closed string background by operators that correspond to the D-brane moving with constant velocity after some instant in time, since it is precisely such operators that gi

Patrick McGraw

We describe a method for simulating the dynamics of an $S_3$ cosmic string network. We use a lattice Monte Carlo to generate initial conditions for the network, which subsequently is allowed to relax continuously according to a simplified model of string dynamics. The dynamics incorporates some novel features which, to our knowledge, have not been studied in

J. Fujimoto, T. Ishikawa, T. Kaneko, K. Kato

grc4f is a Monte-Carlo package for generating e+e- to 4-fermion processes in the standard model. All of the 76 LEP-2 allowed fermionic final state processes evaluated at tree level are included in version 1.0. grc4f addresses event simulation requirements at e+e- colliders such as LEP and up-coming linear colliders. Most of the attractive aspects of grc4f co

Toshiaki Ito, Morimitsu Tanimoto

We examine the unitarity triangle of the KM matrix by using the general quark mass matrices on the NNI basis. The Fritzsch anzätz is modified by introducing four additional parameters. The KM matrix elements are expressed in terms of quark mass ratios, two phases and four additional parameters. It is found that the vertex of the unitarity triangle is predict

G. J. Stephenson, T. Goldman, B. H. J. McKellar

We consider the possibility that neutrinos are coupled very weakly to an extremely light scalar boson. We first analyze the simple problem of one generation of neutrino and show that, for ranges of parameters that are allowed by existing data, such a system can have serious consequences for the evolution of stars and could impact precision laboratory measure

J. L. Hewett, T. Takeuchi, S. Thomas

We summarize the indirect effects of new physics in a variety of processes. We consider precision electroweak measurements, the $g-2$ of the muon, rare decays, meson mixing, CP violation, lepton number violating interactions, double beta decay, and the electric dipole moments of atoms, molecules, and the neutron. We include discussions of both model independ

S. Abachi

A measurement of the cross section for production of single, isolated photons is reported for transverse energies in the range of 10-125 GeV, for two regions of pseudorapidity, |η|<0.9 and 1.6<|η|<2.5. The data represent 12.9 pb-1 of integrated luminosity accumulated in p-pbar collisions at sqrt{s} = 1.8 TeV and recorded with the D0 detector at the Fermilab

O. Yu. Shvedov

The problem of topology change transitions in quantum gravity is investigated from the Wheeler-de Witt wave function point of view. It is argued that for all theories allowing wormhole effects the wave function of the universe is exponentially large. If the wormhole action is positive, one can try to overcome this difficulty by redefinition of the inner prod

K. Ramachandran, Akhil Ranjan

In a noncompact harmonic manifold $M$ we establish finite dimensionality of the eigenspaces $V_λ$ generated by radial eigenfunctions of the form $\cosh r + c$. As a consequence, for such harmonic manifolds, we give an isometric imbedding of $M$ into $(V_λ,B)$, where $B$ is a nondegenerate symmetric bilinear indefinite form on $V_λ$ (analogous to the imbeddin

S. Kubis, M. Kutschera

Recently, Cottingham, Kalafatis and Vinh Mau proposed, in the framework of the Lee-Wick model, a scenario of formation of quark stars in the cosmological quark-hadron phase transition with high degree of supercooling. We show here that the cosmological quark-hadron phase transition in the Lee-Wick model with such a high degree of supercooling cannot be compl

J. M. Speight

A point particle approximation to the classical dynamics of well separated vortices of the abelian Higgs model is developed. A static vortex is asymptotically identical to a solution of the linearized field theory (a Klein-Gordon/Proca theory) in the presence of a singular point source at the vortex centre. It is shown that this source is a composite scalar

I. Terekhov, L. Clavelli

We consider single squark production in $p\overline{p}$ collisions at $\sqrt{s}=1800$ Gev in the light gluino scenario, where production is dominated by the parton subprocess $qg\rightarrow \tilde{q}\tilde{g}\rightarrow q\tilde{g}\tilde{g}$. Computed are the total production cross-sections as well as the contribution of such production to the dijet mass dist

Adam F. Falk

I suggest that the conventional assignment of quantum numbers to the observed charm and bottom baryons is not correct, as these assignments imply large violation of the heavy spin-flavor and light $SU(3)$ symmetries. I propose an alternative interpretation of the observed states, in which the symmetries are preserved. If these novel assignments are right, th

Kevin C. K. Chan

We investigate some modifications of the static BTZ black hole solution due to a chosen asymptotically constant dilaton/scalar. New classes of static black hole solutions are obtained. One of the solutions contains the Martinez-Zanelli conformal black hole solution as a special case. Using quasilocal formalism, we calculate their mass for a finite spatial re

F. Ghaboussi

The physical content of Chern-Simons-action is discussed and it is shown that this action is proportional to the usual charged matter interaction term in electrodynamics.