November 1996 arXiv papers — page 10

V. Dobrosavljevic, G. Kotliar

We present a theory for disordered interacting electrons that can describe both the Mott and the Anderson transition in the respective limits of zero disorder and zero interaction. We use it to investigate the T=0 Mott-Anderson transition at a fixed electron density, as a the disorder strength is increased. Surprisingly, we find two critical values of disord

O. Biham, I. Furman, M. Karimi, G. Vidali

A model that describes self diffusion, island nucleation and film growth on FCC(001) metal substrates is presented. The parameters of the model are optimized to describe Cu diffusion on Cu(001), by comparing activation energy barriers to a full set of barriers obtained from semi-empirical potentials via the embedded atom method. It is found that this model (

I. Furman, O. Biham

The effects of mobility of small islands on island growth in molecular beam epitaxy are studied. It is shown that small island mobility affects both the scaling and morphology of islands during growth. Three microscopic models are considered, in which the critical island sizes are $i^*=1,2$ and 3 (such that islands of size $s \le i^*$ are mobile while island

D. Belitz, T. R. Kirkpatrick, Thomas Vojta

The wavevector and temperature dependent static spin susceptibility, χ_s(Q,T), of clean interacting Fermi systems is considered in dimensions 1\leq d \leq 3. We show that at zero temperature χ_s is a nonanalytic function of |Q|, with the leading nonanalyticity being |Q|^{d-1} for 1<d<3, and Q^2\ln|Q| for d=3. For the homogeneous spin susceptibility we find a

A. E. Trumper, L. O. Manuel, C. J. Gazza, H. A. Ceccatto

We compute the Gaussian-fluctuation corrections to the saddle-point Schwinger-boson results using collective coordinate methods. Concrete application to investigate the frustrated J1-J2 antiferromagnet on the square lattice shows that, unlike the saddle-point predictions, there is a quantum nonmagnetic phase for 0.53 < J2/J1 < 0.64. This result is obtained b

J. Oukbir, A. Blanchard

We use a self-consistent modeling of x-ray cluster properties to constrain cosmological scenarios of structure formation in the case of open cosmological models. We first show that an unbiased open model can reproduce present day observations, provided that the density parameter is in the range 0.15-0.4. Although this estimate is derived in a rather differen

L. S. Georgiev, I. T. Todorov

The Wen-Wu c=-2 model describes the d-wave paired singlet factor of the Haldane-Rezayi (quantum Hall) wave function in terms of an SU(2) doublet of dimension 1 fermions. The resulting CFT involves an infinite sequence of Virasoro primary fields. The superalgebra generated by these fields, on the other hand, admits a set of ground state representations giving

F. Brosens, J. T. Devreese, L. F. Lemmens

Based on the Hellman-Feynman theorem it is shown that the average square radius of a cloud of interacting bosons in a parabolic well can be derived from their free energy. As an application, the temperature dependence of the moment of inertia of non-interacting bosons in a parabolic trap is determined as a function of the number of bosons. Well below the cri

Jan de Boer, Laszlo Feher

A generalized Wakimoto realization of $\widehat{\cal G}_K$ can be associated with each parabolic subalgebra ${\cal P}=({\cal G}_0 +{\cal G}_+)$ of a simple Lie algebra ${\cal G}$ according to an earlier proposal by Feigin and Frenkel. In this paper the proposal is made explicit by developing the construction of Wakimoto realizations from a simple but unconve

J. Kroha, P. Wölfle, T. A. Costi

We show that the presence of Fermi or non-Fermi liquid behavior in the SU(N) x SU(M) Anderson impurity models may be read off the infrared threshold exponents governing the spinon and holon dynamics in a slave boson representation of these models. We construct a conserving T-matrix approximation which recovers the exact exponents with good numerical accuracy

Tomohiro Harada, Takeshi Chiba, Ken-ichi Nakao, Takashi Nakamura

Unlike general relativity, scalar-tensor theories of gravity predict scalar gravitational waves even from a spherically symmetric gravitational collapse. We solve numerically the generation and propagation of the scalar gravitational wave from a spherically symmetric and homogeneous dust collapse under the approximation that we can neglect the back reaction

F. Ghaboussi

We formulate according to the quantum mechanical uncertainty relation a new quantum electrodynamical uncertainty relation $Δ\breve{A} . Δl \sim \hbar/e$ where $\breve{A}$ and $Δl \geq l_B$ are the electromagnetic pure gauge potential, the position uncertainty and the magnetic length, respectively. Then, we show that the observed potential drops on the edge o

C. Devchand, Jeremy Schiff

By relating the two-dimensional U(N) Principal Chiral Model to a simple linear system we obtain a free-field parametrisation of solutions. Obvious symmetry transformations on the free-field data give symmetries of the model. In this way all known `hidden symmetries&#39; and Bäcklund transformations, as well as a host of new symmetries, arise.

U. Feichtinger, O. Moritsch, J. Rant, M. Schweda

A renormalizable rigid supersymmetry for the four dimensional antisymmetric tensor field model in a curved space-time background is constructed. A closed algebra between the BRS and the supersymmetry operators is only realizable if the vector parameter of the supersymmetry is a covariantly constant vector field. This also guarantees that the corresponding tr

J. I. Cirac, P. Zoller, H. J. Kimble, H. Mabuchi

We propose a scheme to utilize photons for ideal quantum transmission between atoms located at spatially-separated nodes of a quantum network. The transmission protocol employs special laser pulses which excite an atom inside an optical cavity at the sending node so that its state is mapped into a time-symmetric photon wavepacket that will enter a cavity at

Daniel I. Fivel

We show that there is essentially only one way to construct a stochastic Schrodinger equation that gives a dynamical account of the transformation of entangled into factorized states and is consistent both with quantum mechanics and required symmetries. The noisy, non-linear term is a unimodular scalar multiple of the time reversal operator that must be pres

A. Kazarnovski-Krol

In this paper we calculate some Generalized Selberg integrals. The answer is expressed in terms of $Γ$-functions. Integrals of this type serve as normalization constants or directly via undoing 2-D integrals for determination of structural constants of operator algebra.

Fred James, Jiri Hoogland, Ronald Kleiss

We discuss the problem of defining an estimate for the error in quasi-Monte Carlo integration. The key issue is the definition of an ensemble of quasi-random point sets that, on the one hand, includes a sufficiency of equivalent point sets, and on the other hand uses information on the degree of uniformity of the point set actually used, in the form of a dis

Martin J. Savage

We examine the role of the Delta-Delta intermediate state in low energy NN scattering using effective field theory. Theories both with and without pions are discussed. They are regulated with dimensional regularization and MSbar subtraction. We find that the leading effects of the Delta-Delta state can be absorbed by a redefinition of the contact terms in a

D. Hüber, H. Witała, A. Nogga, W. Glöckle

We demonstrate that the partial wave decomposition of three-nucleon forces used up to now in momentum space has to be necessarily unstable at high partial waves. This does not affect the applications performed up to now, which were restricted to low partial waves. We present a new way to perform the partial wave decomposition which is free of that defect. Th

Amand Faessler, A. J. Buchmann, M. I. Krivoruchenko, B. V. Martemyanov

If sufficiently light dibaryon resonances exist, a Bose condensate of dibaryons can occur in nuclear matter before the quark-hadron phase transition. Within a relativistic mean-field model we show that heterophase nuclear-dibaryon matter is for a wide set of parameters energetically more favorable than normal nuclear matter. Production of dibaryons is, howev

David Hoffman

Recent uses of differential geometry in materials science are reviewed here, in particular the September issue of the Phil. Trans. Royal Soc., entitled ``Curvature and chemical Structure.&#39;&#39;

Christoph Schweigert

We consider the moduli space of flat G-bundles over the twodimensional torus, where G is a real, compact, simple Lie group which is not simply connected. We show that the connected components that describe topologically non-trivial bundles are isomorphic as symplectic spaces to moduli spaces of topologically trivial bundles with a different structure group.

Sheldon Katz, Cumrun Vafa

We construct local geometric model in terms of F- and M-theory compactification on Calabi-Yau fourfolds which lead to N=1 Yang-Mills theory in d=4 and its reduction on a circle to d=3. We compute the superpotential in d=3, as a function of radius, which is generated by the Euclidean 5-brane instantons. The superpotential turns out to be the same as the poten

C. Aragone, P. J. Arias, A. Khoudeir

We show that locally Lorentz invariant, third order, topological massive gravity can not be broken down neither to the local diffeomorphism subgroup nor to the rigid Poincaré group. On the other hand, the recently formulated, locally diffeomorphism invariant, second order massive triadic (translational) Chern-Simons gravity breaks down on rigid Minkowski spa

Jacques Distler, Andreas Karch

We discuss our attempts to generalize the known examples of dualities in N=1 supersymmetric gauge theories to exceptional gauge groups. We derive some dual pairs from known examples connected to exceptional groups and find an interesting phenomenon: sometimes the full global symmetry is ``hidden&#39;&#39; on the magnetic side. It is not realized as a symmetr

Ranabir Dutt, Asim Gangopadhyaya, Uday P. Sukhatme

It is shown that the operator methods of supersymmetric quantum mechanics and the concept of shape invariance can profitably be used to derive properties of spherical harmonics in a simple way. The same operator techniques can also be applied to several problems with non-central vector and scalar potentials. As examples, we analyze the bound state spectra of

Asim Gangopadhyaya, Uday P. Sukhatme

Motivated by the concept of shape invariance in supersymmetric quantum mechanics, we obtain potentials whose spectrum consists of two shifted sets of equally spaced energy levels. These potentials are similar to the Calogero-Sutherland model except the singular term $αx^{-2}$ always falls in the transition region $-1/4 < α< 3/4$ and there is a delta-function

P. O. Hess, J. C. López Vieyra, C. R. Stephens

A boson mapping of pair field operators is presented. The mapping preserves all hermiticity properties and the Poisson bracket relations between fields and momenta. The most practical application of the boson mapping is to field theories which exhibit bound states of pairs of fields. As a concrete application we consider, in the low energy limit, the Wick-Cu

Brandon Carter, David Langlois

The macroscopic dynamics of a rotating superfluid deviates from that of a simple perfect fluid due to the effect of vorticity quantisation, which gives rise to a substructure of cosmic string type line defects that results in a local anisotropy whereby the effective average pressure in the direction of the vortex lines is reduced below its value in lateral d

Jianming Li, Xingchang Song

Based on the generalized gauge theory on $M^4\times Z_2\times Z_3$, we reconstructed the realistic SU(5) Grand Unified model by a suitable assignment of fermion fields. The action of group elements $Z_2$ on fermion fields is the charge conjugation while the action of $Z_3$ elements represent generation translation. We find that to fit the spontaneous symmetr

Ya. Azimov

We reconsider Hara&#39;s theorem in its relation to the well-known properties of beta-decay. All assumptions necessary for the theorem to be true are explicitly formulated. Further, we study the W-exchange contribution to weak radiative decays and show that it does not violate Hara&#39;s theorem. However, this contribution reveals the essential role of parti

Gary R. Goldstein

Top-antitop quark pairs produced at the Tevatron have a sizeable spin correlation. That correlation feeds into the angular distribution of the decay products, particularly in the dilepton channel. Including the expected correlation in an overall analysis of a handful of actual dilepton events continues to favor a lower top mass (centered on 155 GeV) than the

Patrick Labelle, S. Mohammad Zebarjad

We rederive the $O(α^5)$ shift of the hydrogen levels in the non-recoil ($m_e/m_P \to 0$) limit using Nonrelativistic QED (NRQED), an effective field theory developed by Caswell and Lepage (Phys. Lett. 167B, 437 (1986)). Our result contains the Lamb shift as a special case. Our calculation is far simpler than traditional approaches and has the advantage of b

Duane A. Dicus, S. Nandi

In supergravity theories with a very light gravitino, the gluino decays dominantly to a gluon and a gravitino. This results in a much larger missing $E_T$ for the multijet final states in hadronic colliders. We use the latest Tevatron data for the multijet final states to set a new absolute lower bound of 3.0 x 10^{-13} GeV for the light gravitino mass.

Hilmar Forkel, Marina Nielsen

We study isospin breaking instanton corrections to the operator product expansion of the nucleon correlation functions. After a comparison with quark model calculations based on the &#39;t Hooft interaction, we examine the role of instantons in the corresponding QCD sum rules. Instanton contributions are found to be absent in the chirally even sum rule, but

Adam P. Szczepaniak, Eric S. Swanson

The Dirac structure of confinement is shown to be of timelike-vector nature in the heavy quark limit of QCD. This stands in contradiction with the phenomenological success of the Dirac scalar confining potential. A resolution is achieved through the demonstration that an effective scalar interaction is dynamically generated by nonperturbative mixing between

Csaba Csaki

A promising solution to the doublet-triplet splitting problem of SUSY GUT&#39;s is the Higgs as pseudo-Goldstone boson mechanism. We present two models which naturally implement this idea and extend one of them to include fermion masses. We examine the phenomenological consequences of this mechanism and present the favored parameter region.

Wolfgang Ochs

The perturbative QCD approach to multiparticle production assuming Local Parton Hadron Duality (LPHD) and some recent results are discussed. Finite asymptotic scaling limits are obtained for various observables, after an appropriate rescaling, in the Double Logarithmic Approximation (DLA). Non-asymptotic corrections are also known in some cases. The DLA appl

Torben Hannah

The inverse-amplitude method is applied to the one-loop chiral expansion of the pion, kaon, and $K_{l3}$ form factors. Since these form factors are determined by the same chiral low-energy constants, it is possible to obtain finite predictions for the inverse-amplitude method. It is shown that this method clearly improves one-loop chiral perturbation theory,

J. Kwiecinski

Elements of the pomeron phenomenology within the Regge pole exchange picture are recalled. This includes discussion of the high energy behaviour of total cross-sections, the triple pomeron limit of the diffractive dissociation and the single particle distributions in the central region. The BFKL pomeron and QCD expectations for the small $x$ behaviour of the

K. Schertler, C. Greiner, M. H. Thoma

We investigate the properties of strange quark matter at zero temperature including medium effects. The quarks are considered as quasiparticles which acquire an effective mass generated by the interaction with the other quarks of the dense system. The effective quark masses are derived from the zero momentum limit of the dispersion relations following from a

Tsutom Hasuike, Toshihiko Hattori, Toshio Hayashi, Seiichi Wakaizumi

Due to the large mass of top quark, CP violation in the top-quark decay is sensitive to the interactions mediated by Higgs bosons. We consider CP violation in $t\rightarrow W^+ b$ decay by calculating consistently in unitary gauge the CP-violating up-down asymmetry of the leptons from $W$ boson decays in $t\rightarrow W^+ b$, defined by Grzcadkowski and Guni

Janet L. Houser, Joan M. Centrella

We carry out 3-D numerical simulations of the dynamical instability in rapidly rotating stars initially modeled as polytropes with n = 1.5, 1.0, and 0.5. The calculations are done with a SPH code using Newtonian gravity, and the gravitational radiation is calculated in the quadrupole limit. All models develop the global m=2 bar mode, with mass and angular mo

P. T. Chrusciel, G. J. Galloway

It is folklore knowledge amongst general relativists that horizons are well behaved, continuously differentiable hypersurfaces except perhaps on a negligible subset one needs not to bother with. We show that this is not the case, by constructing a Cauchy horizon, as well as a black hole event horizon, which contain no open subset on which they are differenti

Priya Mahadevan, N. Shanthi, D. D. Sarma

We have analyzed the ab-initio local density approximation band structure calculations for the family of perovskite oxides, La$M$O$_3$ with $M$=Ti-Ni within a parametrized nearest neighbor tight-binding model and extracted various interaction strengths. We study the systematics in these interaction parameters across the transition metal series and discuss th

F. W. J. Hekking, L. I. Glazman

We study the oscillatory flux dependence of the supercurrent in a thin superconducting loop, closed by a Josephson junction. Quantum fluctuations of the order parameter in the loop affect the shape and renormalize the amplitude of the supercurrent oscillations. In a short loop, the amplitude of the sinusoidal flux dependence is suppressed. In a large loop, t

P. Beran

The 2D system of electron confined to the lowest Landau level is described using a representation of the density matrix depending both on electron and hole coordinates. Condensation of the electron system into a fractional quantum Hall state is associated to clustering of particle and hole coordinates. The correlation of particle and hole coordinates is stud

J. M. Tranquada, P. Wochner, A. R. Moodenbaugh, D. J. Buttrey

At low temperature the holes doped into the NiO(2) planes of La(2)NiO(4.133) by the excess oxygen collect in diagonal stripes that separate narrow antiferromagnetic domains. The magnetic order drops abruptly to zero at T_m = 110.5 K, but charge order remains with a period of 3a/2. We show that application of a magnetic field in the regime T > T_m induces sta

G. Foltin, R. Bausch, R. Blossey

The profile of a critical hole in an undercooled wetting layer is determined by the saddle-point equation of a standard interface Hamiltonian supported by convenient boundary conditions. It is shown that this saddle-point equation can be mapped onto an autonomous dynamical system in a three-dimensional phase space. The corresponding flux has a polynomial for

K. Ziegler

A two-dimensional lattice system of non-interacting electrons in a homogeneous magnetic field with half a flux quantum per plaquette and a random potential is considered. For the large scale behavior a supersymmetric theory with collective fields is constructed and studied within saddle point approximation and fluctuations. The model is characterized by a br

Heinz-Olaf Muller, K. A. Chao

The qualities of electron refrigeration by means of tunnel junctions between superconducting and normal--metal electrodes are studied theoretically. A suitable approximation of the basic expression for the heat current across those tunnel junctions allows the investigation of several features of the device such as its optimal bias voltage, its maximal heat c

Haye Hinrichsen, Joshua S. Weitz, Eytan Domany

We present a general definition of damage spreading in a pair of models. Using this general framework, one can define damage spreading in an objective manner, that does not depend on the particular dynamic procedure that is being used. The formalism is applied to the Domany-Kinzel cellular automaton in one dimension; the active phase of this model is shown t

S. Curnoe, P. C. E. Stamp

We consider the self-energy and quasiparticle spectrum, for both electrons interacting with phonons, and composite fermions interacting with gauge fluctuations. In both cases we incorporate the singular structure arising from Landau level quantization in a finite field. This is then used to determine the renormalised gap between the Fermi energy and the firs

A. V. Puchkov, D. N. Basov, T. Timusk

We report on a study of the electromagnetic response of three different families of high-T_c superconductors that in combination allowed us to cover the whole doping range from under- to overdoped. The discussion is focused on the ab-plane charge dynamics in the {\it pseudogap state} which is realized in underdoped materials below a characteristic temperatur

Carl de Marcken

This thesis presents a computational theory of unsupervised language acquisition, precisely defining procedures for learning language from ordinary spoken or written utterances, with no explicit help from a teacher. The theory is based heavily on concepts borrowed from machine learning and statistical estimation. In particular, learning takes place by fittin

Markus Walther

This paper details a simple approach to the implementation of Optimality Theory (OT, Prince and Smolensky 1993) on a computer, in part reusing standard system software. In a nutshell, OT&#39;s GENerating source is implemented as a BinProlog program interpreting a context-free specification of a GEN structural grammar according to a user-supplied input form.

Heino Falcke, Fulvio Melia

The evolution of an accretion disk can be influenced significantly by the deposition of mass and angular momentum by an infalling Bondi-Hoyle wind. Such a mass influx impacts the long-term behavior of the disk by providing additional sources of viscosity and heating. In this paper, we derive and solve the disk equations when these effects are taken into acco

Y. -Z. Qian, S. E. Woosley

During the first 20 seconds of its life, the enormous neutrino luminosity of a neutron star drives appreciable mass loss from its surface. Previous investigations have shown that this neutrino-driven wind could be the site where the r-process occurs. The nucleosynthesis is sensitive to four physical parameters characterizing the wind: its mass loss rate, the

Ofer Lahav

We discuss cosmological inference from galaxy surveys at low and high redshifts. Studies of optical and IRAS redshift surveys with median redshift ${\bar z} \sim 0.02$ yield measurements of the density parameter $Ω$ and the power-spectrum of density fluctuations, but both cannot easily be related to the properties of the underlying mass distribution due to t

Stephane Courteau

Recent ground-based photometric investigations suggest that central regions of late-type spirals are closely coupled to the inner disk and probably formed via secular evolution. Evidence presented in support of this model includes the predominance of exponential bulges, the correlation of bulge and disk scale lengths, blueness of the bulge and small differen

Ofer Lahav

The summary talk of IAU179 &#39;New Horizons from Multi-Wavelengths Sky Surveys&#39;, held in Baltimore in August 1996. First I summarize the highlights in different wavelengths as described in the oral presentations. Then I discuss the need for statistical techniques, some key astrophysical questions which should be addressed by multi-wavelength approaches,

K. D. Gordon, C. L. Mulliss

Using the 1-m telescope at Ritter Observatory, we took 36 observations of zeta^2 Coronae Borealis with a fiber-fed echelle spectrograph. From these observations, zeta^2 CrB was found to be a triple system and a new spectroscopic orbit was calculated. This orbit has two periods, a 1.72357 day period for the inner binary composed of zeta^2 CrB A & B and a 251

J. Oukbir, J. G. Bartlett, A. Blanchard

We present a self-consistent approach to the modeling of X-ray clusters of galaxies in a flat universe. Employing the Press and Schechter (1974) formalism to derive the mass function and relating the observable properties of clusters to their virial mass allows us to study the cluster X-ray distribution functions and their evolution with redshift. This appro

S. Vitale, M. Cerdonio, E. Coccia, A. Ortolan

In this paper we discuss how the standard optimal Wiener filter theory can be applied, within a linear approximation, to the detection of an isotropic stochastic gravitational-wave background with two or more detectors. We apply then the method to the AURIGA-NAUTILUS pair of ultra low temperature bar detectors, near to operate in coincidence in Italy, obtain

Tomaso Belloni, Luca Zampieri, Sergio Campana

We present the results of a systematic search for old isolated neutron stars (ONSs) in the direction of two giant molecular clouds in Cygnus (Rift and OB7). From theoretical calculations, we expect the detection of a large number of ONSs with the PSPC on board ROSAT. By analyzing the PSPC pointings in the direction of the clouds, we find four sources charact

Simon P Goodwin

N-body simulations are used to model the early evolution of globular clusters. These simulations include residual gas which was not turned into stars which is expelled from the globular cluster by the actions of massive stars. The results of these simulations are compared to observations of 8 LMC globular clusters less than 100 Myr old. These observations ar

L. Titarchuk, A. Mastichiadis, N. D. Kylafis

Spectral formation in steady state, spherical accretion onto neutron stars and black holes is examined by solving numerically and analytically the equation of radiative transfer. The photons escape diffusively and their energy gains come from their scattering off thermal electrons in the converging flow of the accreting gas. We show that the bulk motion of t

Misha Verbitsky

Let $M$ be a singular hyperkaehler variety, obtained as a moduli space of stable holomorphic bundles on a compact hyperkaehler manifold (alg-geom/9307008). Consider $M$ as a complex variety in one of the complex structures induced by the hyperkaehler structure. We show that normalization of $M$ is smooth, hyperkaehler and does not depend on the choice of ind

Klaus Altmann, Arne B. Sletsjoe

We compute the Andre-Quillen cohomology of an affine toric variety. The best results are obtained either in the general case for the first three cohomology groups, or in the case of isolated singularities for all cohomology groups, respectively.

Robert F. Coleman, Bas Edixhoven

Let $p$ be a prime number and $N$ an integer prime to $p$. We show that the operator $U_p$ on the space of cuspidal modular forms of level $pN$ and weight two is semi-simple. It follows from this that the Hecke algebra acting on the space of weight two forms of level $M$ is reduced if $M$ is cube free. Assuming Tate&#39;s conjecture for cycles on smooth proj

H. Lu, C. N. Pope

We discuss the vertical dimensional reduction of M-branes to domain walls in D=7 and D=4, by dimensional reduction on Ricci-flat 4-manifolds and 7-manifolds. In order to interpret the vertically-reduced 5-brane as a domain wall solution of a dimensionally-reduced theory in D=7, it is necessary to generalise the usual Kaluza-Klein ansatz, so that the 3-form p

Valeri V. Dvoeglazov

It is shown that the Evans-Vigier modified electrodynamics is compatible with the Relativity Theory.

Glenn Barnich, Viqar Husain

We give an SU(2) covariant representation of the constraints of Euclidean general relativity in the Ashtekar variables. The guiding principle is the use of triads to transform all free spatial indices into SU(2) indices. A central role is played by a special covariant derivative. The Gauss, diffeomorphism and Hamiltonian constraints become purely algebraic r

Bhuvnesh Jain, Uros Seljak

Weak lensing by large scale structure induces correlated ellipticities in the images of distant galaxies. The two-point correlation is determined by the matter power spectrum along the line of sight. We use the fully nonlinear evolution of the power spectrum to compute the predicted ellipticity correlation. We present results for different measures of the se

Zack Sullivan

We calculate the supersymmetric QCD correction to top-quark production at the Fermilab Tevatron, allowing for arbitrary left-right mixing of the squarks. We find that the correction is significant for several combinations of gluino and squark masses, e.g. +33% for m_{\tilde g}=200 GeV, m_{\tilde t} = m_{\tilde q} =75 GeV.

Ariel R. Zhitnitsky

We give some general arguments in favor of the large magnitude of matrix elements of an operator associated with nonvalence quarks in heavy hadrons. We estimate a strange matrix element for Λ_b baryon whose valence content is b, u, d quarks. We find a noticeable contribution of the strange quark into the heavy baryon mass on the level 200-300 MeV. The argume

Barry M. McCoy, William P. Orrick

We present analytic expressions for the single particle excitation energies of the 8 quasi-particles in the lattice $E_8$ Ising model and demonstrate that all excitations have an extended Brillouin zone which, depending on the excitation, ranges from 0<P < 4πto 0< P< 12 π. These are compared with exact diagonalizations for systems through size 10 and with th

Andrei Okounkov

We consider 3-parametric polynomials which replace the A-series interpolation Macdonald polynomials in the BC case. For these polynomials, we prove: an integral representation, a combinatorial formula, Pieri-type rules, Cauchy identity, and we also show that they do not satisfy any rational q-difference equation. We also prove a binomial formula for the 6-pa

H. R. Karadayi

It is shown that there are infinitely many formulas to calculate multiplicities of weights participating in irreducible representations of $A_N$ Lie algebras. On contrary to recursive character of Kostant and Freudenthal multiplicity formulas, they provide us systems of linear algebraic equations with N-dependent polinomial coefficients. These polinomial coe

Giuseppe Tormen

We use N-body simulations to study the infall of dark matter haloes onto rich clusters of galaxies. After identification of all cluster progenitors in the simulations, we select those haloes which accrete directly onto the main cluster progenitor. We construct the mass function of these merging satellites, and calculate the main orbital parameters for the ac

Lior M. Burko

The interaction of the unboundedly blue-shifted photons of the cosmic microwave background radiation with a physical object falling towards the inner horizon of a Reissner-Nordstrom black hole is analyzed. To evaluate this interaction we consider the QED effects up to the second order in the perturbation expansion. We then extrapolate the QED effects up to a

I Cassidy, D. J. Raine

We present a unified picture of active galactic nuclei which we construct from a detailed model of line emission in the active source in NGC 4151. In this scheme NGC 4151 can be regarded as a typical active nucleus, special only in its orientation. This alleviates a number of problems with a unified picture based on a dusty molecular torus with a fixed struc

Viktor L. Ginzburg

We introduce and study a new spectral sequence associated with a Poisson group action on a Poisson manifold and an equivariant momentum mapping. This spectral sequence is a Poisson analog of the Leray spectral sequence of a fibration. The spectral sequence converges to the Poisson cohomology of the manifold and has the $E_2$-term equal to the tensor product

Dao-Neng Gao, Bing An Li, Mu-Lin Yan

To one-loop order and $O(α_{em})$, the electromagnetic mass splittings of $π$, $a_1$, $K$, $K_1(1400)$, and $K^*(892)$ are calculated in the framework of $U(3)_L\times U(3)_R$ chiral field theory. The logarithmic divergences emerging in the Feynman integrations of the mesonic loops are factorized by using an intrinsic parameter $g$ of this theory. No other a

E. A. Kuraev

The result of lowest-order perturbation theory calculations of the photon and positron spectra in radiative pion(e2) decay are generalized to all orders of perturbation theory using the structure-function method. An additional source of radiative corrections to the ratio of the positron and muon channels of pion decay, due to emission of virtual and real pho

Riccardo Giannitrapani

We examine the longstanding problem of introducing a time observable in Quantum Mechanics; using the formalism of positive-operator-valued measures we show how to define such an observable in a natural way and we discuss some consequences.

Miao LI, Tamiaki Yoneya

We argue that the space-time uncertainty relation of the form $ΔX ΔT \gtrsim α&#39;$ for the observability of the distances with respect to time, $ΔT$, and space, $ΔX$, is universally valid in string theory including D-branes. This relation has been previously proposed by one (T.Y.) of the present authors as a simple qualitative representation of the perturb

Valeri V. Dvoeglazov

We find a mapping between antisymmetric tensor matter fields and the Weinberg&#39;s 2(2j+1)- component &#34;bispinor&#34; fields. Equations which describe the j=1 antisymmetric tensor field coincide with the Hammer-Tucker equations entirely and with the Weinberg ones within a subsidiary condition, the Klein-Gordon equation. The new Lagrangian for the Weinber

Janne Ruostekoski, Dan F. Walls

We calculate the spectrum of the scattered light from quantum degenerate atomic gases obeying Bose-Einstein statistics. The atoms are assumed to occupy two ground states which are optically coupled through a common excited state by two low intensity off-resonant light beams. In the presence of a Bose condensate in both ground states, the atoms may exhibit li

A. G. Bytsko, V. Schomerus

Within the framework of the discrete Wess-Zumino-Novikov-Witten theory we analyze the structure of vertex operators on a lattice. In particular, the lattice analogues of operator product expansions and braid relations are discussed. As the main physical application, a rigorous construction for the discrete counterpart g_n of the group valued field g(x) is pr

Yu. A. Krotov, D. -H. Lee, Steven G. Louie

According to band theory, an ideal undoped (n,n) carbon nanotube is metallic. We show that the electron-electron interaction causes it to become Mott insulating with a spin gap. More interestingly, upon doping it develops superconducting fluctuations.

C. R. Hu, B. Muller

We propose a formulation of the long-distance dynamics of gauge theories at finite temperature on a lattice in Minkowski space, including the effects of hard thermal loops on the dynamics of the long wavelength modes. Our approach is based on the dual classical limits of quantum fields as waves and particles in the infrared and ultraviolet limits, respective

Peter Bouwknegt, Jim McCarthy, Peter van Nieuwenhuizen

We introduce the notion of a fused quantum superplane by allowing for terms $θθ\sim x$ in the defining relations. We develop the differential calculus for a large class of fused quantum superplanes related to particular solutions of the Yang-Baxter equation.

K. K. Nwabueze

The Artin exponent induced from cyclic subgroups of finite groups was studied extensively by T.Y. Lam. A Burnside ring theoretic version of Lam&#39;s results for $p$-groups was given by the author in an earlier paper. Here we look at the Artin exponent induced from the elementary abelian subgroups of finite $p$-groups using some results of A. Dress.

V. Dzhunushaliev

The spherically and cylindrically symmetric solutions of the $SU(3)$ Yang - Mills theory are obtained. The corresponding gauge potential has the confining properties. It is supposed that: a) the spherically symmetric solution is a field distribution of the classical ``quark&#39;&#39; and in this sense it is similar to the Coulomb potential; b) the cylindrica

Kimball A. Milton

The Casimir energy or stress due to modes in a D-dimensional volume subject to TM (mixed) boundary conditions on a bounding spherical surface is calculated. Both interior and exterior modes are included. Together with earlier results found for scalar modes (TE modes), this gives the Casimir effect for fluctuating ``electromagnetic&#39;&#39; (vector) fields i

R. Banerjee, H. J. Rothe, K. D. Rothe Comments 9 pages, LaTeX

Following systematically the generalized Hamiltonian approach of Batalin and Fradkin, we demonstrate the equivalence of a self-dual model with the Maxwell-Chern-Simons theory by embedding the former second-class theory into a first-class theory.

L. Andrianopoli, R. D&#39;Auria

In this lecture moduli dependent charges for p-extended objects are analyzed for generic N-extended supergravities in dimensions 4 \leq D <10. Differential relations and sum rules among the charges are derived.

P. S. Howe, P. C. West

The superconformal invariants in analytic superspace are found. Superconformal invariance is shown to imply that the Green&#39;s functions of analytic operators are invariant holomorphic sections of a line bundle on a product of certain harmonic superspaces. It is argued that the correlation functions for a class of sufficiently low dimension gauge invariant