September 1996 arXiv papers — page 7

J. Blümlein, M. Botje, C. Pascaud, S. Riemersma

Seven next-to-leading order QCD evolution programs are compared. The deviations of the results due to different theoretical prescriptions for truncating the perturbative series are clarified, and a numerical agreement between five codes of better than 0.1% is achieved. Reference results for further comparison are provided.

D. Bardin, J. Blümlein, P. Christova, L. Kalinovskaya

We describe several numerical results for radiative corrections for deep inelastic $ep$ scattering at HERA which are calculated using the HECTOR package. We present radiative corrections for ten different choices of kinematical variables for unpolarized neutral and charged current deep inelastic scattering. Radiative corrections for neutral current scatterin

Afsar Abbas

The exact QCD is one of the cornerstones of particle physics. Hence it would appear that there should exist no physical situation where a broken version of QCD may have any relevance. However, here I shall show that a spontaneously broken version of QCD may have been significant in an early universe scenario. How this can be made compatible with the exact QC

Naoyuki Haba

We reanalyze the possibility of CP violation in the Higgs sector of the minimal supersymmetric standard model (MSSM). Contrary to the result of previous analysis, spontaneous CP violation can not occur by only chargino and neutralino radiative corrections since the vacuum does not stable. Top and stop radiative corrections are crucially needed. However even

J. Blümlein, S. Riemersma

We perform a numerical study of the QCD corrections to the structure function $F_L(x,Q^2)$ in the HERA energy range. The $K$--factors are of $O(30%)$ and larger in parts of the kinematic range. The relative corrections to $F_L^{c\overline{c}}$ turn out to be scale dependent and partially compensate contributions to the massless terms.

M. C. Gonzalez-Garcia, S. F. Novaes

We investigate the effects induced by excited leptons, at the one-loop level, in the anomalous magnetic and weak-magnetic form factors of the leptons. Using a general effective Lagrangian approach to describe the couplings of the excited leptons, we compute their contributions to the weak-magnetic moment of the $τ$ lepton, which can be measured on the $Z$ pe

A. Masiero, L. Silvestrini

B physics represents a privileged place to look for supersymmetry (SUSY) through its virtual effects. Here we discuss rare B decays ($b \to s γ$, $b \to s g$, $b \to s l^{+} l^{-}$) and $B-\bar{B}$ oscillations in the context of low-energy SUSY. We outline the variety of predictions that arise according to the choice of the SUSY extension ranging from what w

M. A. Ivanov, V. E. Lyubovitskij

Semileptonic decays of bottom and charm baryons are considered within a relativistic three-quark model with the Gaussian shape for the baryon-three-quark vertex and standard quark propagators.

Xiang-Qian Luo

We review the recent glueball mass calculations using an efficient method for solving the Schrödinger equation order by order with a scheme preserving the continuum limit. The reliability of the method is further supported by new accurate results for (1+1)-dimensional $σ$ models and (2+1)-dimensional non-abelian models. We present first and encouraging data

J. Smith, R. Vogt

The cross sections for charm and bottom quark production in the threshold region are discussed. We consider the effects of an all order resummation of initial state soft-plus-virtual gluon radiation on the total cross sections compared to the order $α_s^3$ results.

C. Alexandrou, A. Boriçi, A. Feo, Ph. de Forcrand

We present first results, for heavy to moderate quark masses, of a study of thermodynamic properties of 1-flavor QCD, using the multiboson algorithm.

H. Suganuma, S. Sasaki, H. Ichie, F. Araki

We study the relation between instantons and monopoles in the abelian gauge. First, we investigate the monopole in the multi-instanton solution in the continuum Yang-Mills theory using the Polyakov gauge. At a large instanton density, the monopole trajectory becomes highly complicated, which can be regarded as a signal of monopole condensation. Second, we st

David Gerdes

I summarize recent top quark physics results from the Fermilab Tevatron experiments. Since the observation of the top quark by CDF and D0 in 1995, the experimental focus has shifted to a detailed study of the top quark's properties. This article describes recent measurements of the top quark production cross section, mass, kinematic properties, branching

Vladimir S. Mashkevich

This paper is a continuation of the papers [gr-qc/9409010, gr-qc/9505034, gr-qc/9603022, gr-qc/9609035] and is devoted to the riddle of the origin of the arrow of time. The problem of time orientation reduces to that of the difference between the past and the future. The riddle escapes solution in deterministic dynamics and in the dynamics of standard indete

D. K. Klimov, D. Thirumalai

We use a three dimensional cubic lattice model of proteins to study their properties that determine folding to the native state. The protein chain is modeled as a sequence of $N$ beads. The interactions between beads are taken from a Gaussian distribution of energies. We studied 56 sequences with unique ground states for $N = 15$ and $27$. Thermodynamic and

Henrik Kajueter, Gabriel Kotliar

We investigate the Mott transition in infinite dimensions in the orbitally degenerate Hubbard model. We find that the qualitative features of the Mott transition found in the one band model are also present in the orbitally degenerate case. Surprisingly, the quantitative aspects of the transition around density one are not very sensitive to orbital degenerac

C. L. Kane, Matthew P. A. Fisher

A long skinny gate across a fractional quantum Hall fluid at filling $ν=1/m$ with odd integer $m$, creates a novel one-dimensional (1d) system which is isomorphic to a disordered 1d electron gas with {\it attractive} interactions. By varying the gate potential along such a line junction, it should be possible to tune through the 1d localization transition, p

D. V. Khveshchenko, Michael Reizer

The method of the quantum kinetic equation is applied to the problem of renormalization of the conductivity of normal metals by gauge electron-electron interactions. It is shown that in the three-dimensional case the relativistic electromagnetic interaction (vector interaction of electrons with transverse photons) leads to an unusual temperature dependence,

Yupeng Wang, Johannes Voit

The single impurity Kondo problem in the one-dimensional $δ$-potential Fermi gas is exactly solved for two sets of special coupling constants via Bethe ansatz. It is found that ferromagnetic Kondo screening does occur in one case which confirms the Furusaki-Nagaosa conjecture while in the other case it does not, which we explain in a simple physical picture.

Martin Kraus, Wolfgang Wintz, Udo Seifert, Reinhard Lipowsky

The shape dynamics of fluid vesicles is governed by the coupling of the flow within the two-dimensional membrane to the hydrodynamics of the surrounding bulk fluid. We present a numerical scheme which is capable of solving this flow problem for arbitrarily shaped vesicles using the Oseen tensor formalism. For the particular problem of simple shear flow, stat

D. Jezek, M. Guilleumas, M. Pi, M. Barranco

At low temperatures and 3He concentrations below 6.6 %, there is experimental evidence about the existence in liquid helium mixtures, of stable vortices with 3He-rich cores. When the system is either supersaturated or submitted to a tensile strength, vortices lose stability becoming metastable and eventually completely unstable, so that their cores freely ex

Hideo Yoshioka, Yoshikazu Suzumura

Two chains of Luttinger liquids coupled by both interchain hopping and interchain interaction are investigated. A degeneracy of two kinds of dominant states with in phase and out of phase ordering in the absence of the hopping is removed since the transverse fluctuation of charge density is completely gapful and that of spin density has two kinds of excitati

Lapo Casetti, Cecilia Clementi, Marco Pettini

This paper deals with the problem of analytically computing the largest Lyapunov exponent for many degrees of freedom Hamiltonian systems. This aim is succesfully reached within a theoretical framework that makes use of a geometrization of newtonian dynamics in the language of Riemannian geometry. A new point of view about the origin of chaos in these system

W. B. Landsman, A. V. Sweigart, R. C. Bohlin, S. G. Neff

We present a 1620 A image of the nearby globular cluster NGC 6752 obtained with the Ultraviolet Imaging Telescope (UIT) during the Astro-2 mission of the Space Shuttle Endeavour in 1995 March. An ultraviolet-visible color-magnitude diagram (CMD) is derived for 216 stars matched with the visible photometry of Buonanno et al. (1986). This CMD provides a nearly

S. B. Popov, M. E. Prokhorov

We present here the computer model of the distribution of the luminosity, produced by old isolated neutron stars (OINSs) accreting from the interstellar medium (ISM). We show, that for different mean velocities of OINSs the distribution of the luminosity has a torus-like structure, with the maximum at $\approx 5 kpc$.

Annette M. N. Ferguson, Rosemary F. G. Wyse, J. S. Gallagher

We present deep Halpha+[NII], [SII] (6716,6731A) and [OII] (3726,3729A) images of the highly inclined, actively star--forming SBm galaxy NGC 55, located in the nearby Sculptor Group. Due to its proximity, NGC 55 provides a unique opportunity to study the disk--halo interface in a late--type galaxy with unprecedented spatial resolution. Our images reveal a sp

Terry P. Walker

In this manifesto I review the status of standard BBN in light of recent observational data (e.g., QSO deuterium and Izotov etal. helium-4).

K. Subramanian

Magnetic fields correlated on several kiloparsec scales are seen in spiral galaxies. Their origin could be due to the winding up of a primordial cosmological field or due to amplification of a small seed field by a turbulent galactic dynamo. Both options have difficulties: There is no known battery mechanism for producing the required primordial field. Equal

N. Metcalfe, T. Shanks, A. Campos, R. Fong

Sensitive optical surveys have revealed a large population of `faint blue galaxies' which are believed to be young galaxies, observed close to their time of formation. But there has been considerable uncertainty regarding the epochs at which these galaxies are observed, owing to the difficulties inherent in determining spectroscopic redshifts for very fa

Roy Maartens

I review the causal relativistic thermodynamics developed by Israel and Stewart, and discuss some applications in cosmology and astrophysics. The lectures begin with an overview of relativistic fluid dynamics (in a covariant formalism) and equilibrium thermodynamics. Causal bulk viscosity in cosmology is considered in detail, including some new results.

J. -C. Cuillandre, Y. Mellier, J. -P. Dupin, P. Tilloles

We describe a new 4096x4096 pixel CCD mosaic camera (MOCAM) available at the prime focus of the Canada-France-Hawaii Telescope (CFHT). The camera is a mosaic of four 2048x2048$ Loral frontside-illuminated CCDs with 15 $μ$m pixels, providing a field of view of 14'x14' at a scale of 0.21''/pixel. MOCAM is equipped with B, V, R and I filters and

J. E. J. Lovell, J. E. Reynolds, D. L. Jauncey, P. R. Backus

Measurements of the properties of gravitational lenses have the power to tell us what sort of universe we live in. The brightest known radio Einstein ring/gravitational lens PKS 1830-211 (Jauncey et al., 1991), whilst obscured by our Galaxy at optical wavelengths, has recently been shown to contain absorption at the millimetre waveband at a redshift of 0.89

A. Brandhuber, S. Stieberger

We determine the mass dependence of the coupling constant for N=2 SYM with N_f=1,2,3 and 4 flavours. All these cases can be unified in one analytic expression, given by a Schwarzian triangle function. Moreover we work out the connection to modular functions which enables us to give explicit formulas for the periods. Using the form of the J-functions we are a

John C. Baez

A 2-Hilbert space is a category with structures and properties analogous to those of a Hilbert space. More precisely, we define a 2-Hilbert space to be an abelian category enriched over Hilb with a *-structure, conjugate-linear on the hom-sets, satisfying <fg,h> = <g,f*h> = <f,hg*>. We also define monoidal, braided monoidal, and symmetric monoidal versions o

Xiangdong Ji

We study in QCD the physics of deeply-virtual Compton scattering (DVCS)---the virtual Compton process in the large s and small t kinematic region. We show that DVCS can probe a new type of off-forward parton distributions. We derive an Altarelli-Parisi type of evolution equations for these distributions. We also derive their sum rules in terms of nucleon for

J. R. Reyes Martínez

The correlation functions of the Z-invariant Ising model are calculated explicitly using the Vertex Operators language developed by the Kyoto school.

I. Bojak, M. Ernst

It has been observed recently that a consistent LO BFKL gluon evolution leads to a steep growth of F_2(x,Q^2) for x -> 0 almost independently of Q^2. We show that current data from the DESY HERA collider are precise enough to finally rule out a pure BFKL behaviour in the accessible small x region. Several attempts have been made by other groups to treat the

B. -D. Doerfel, St. Meissner

In this paper we calculate the finite-size corrections of an anisotropic integrable spin chain, consisting of spins s=1 and s=1/2. The calculations are done in two regions of the phase diagram with respect to the two couplings $\bar{c}$ and $\tilde{c}$. In case of conformal invariance we obtain the final answer for the ground state and its lowest excitations

John Cardy, Uwe C. Täuber

A systematic theory for the diffusion--limited reaction processes $A + A \to 0$ and $A \to (m+1) A$ is developed. Fluctuations are taken into account via the field--theoretic dynamical renormalization group. For $m$ even the mean field rate equation, which predicts only an active phase, remains qualitatively correct near $d_c = 2$ dimensions; but below $d_c&

N. David Mermin

I list several strong requirements for what I would consider a sensible interpretation of quantum mechanics and I discuss two simple theorems. One, as far as I know, is new; the other was only noted a few years ago. Both have important implications for such a sensible interpretation. My talk will not clear everything up; indeed, you may conclude that it has

Zdenek Hradil

New algorithm for quantum state estimation based on the maximum likelihood estimation is proposed. Existing techniques for state reconstruction based on the inversion of measured data are shown to be overestimated since they do not guarantee the positive definiteness of the reconstructed density matrix.

W-S. Chung

In this paper the coherent state for $gl_q(n)$-covariant oscillators is constructed and is shown to satisfy the completeness relation. And the q-analogue of quantum mechanics in n dimensions is obtained by using $gl_q(n)$ oscillators.

W-S. Chung

Two types of the coherent states for two parameter deformed multimode oscillator system are investigated. Moreover, two parameter deformed $gl(n)$ algebra and deformed symmetric states are constructed.

W-S. Chung

In this paper Witten type deformation of osp(1/2) algbera is introduced and its realization and matrix representation are obtained. The matrix representation is shown to be possible only when the dimension is odd.

M. Chiapparini, A. Delfino, M. Malheiro, A. Gattone

We study finite nuclei, at the mean-field level, using the Zimanyi-Moskowski model and one of its variations (the ZM3 model). We calculate energy levels and ground-state properties in nuclei where the mean-field approach is reliable. The role played by the spin-orbit potential in sorting out mean-field model descriptions is emphasized.

Vladimir A. Zorich

An intrinsic definition in terms of conformal capacity is proposed for the conformal type of a Carnot--Carathéodory space (parabolic or hyperbolic). Geometric criteria of conformal type are presented. They are closely related to the asymptotic geometry of the space at infinity and expressed in terms of the isoperimetric function and the growth of the area of

Valeri V. Dvoeglazov

This is a brief introduction on the graduate level to recent ideas in the Weinberg $(j,0)\oplus (0,j)$ formalism, appearing after presentation of the Bargamann-Wightman-Wigner-type quantum field theory by D. V. Ahluwalia {\it et al.}

Valeri V. Dvoeglazov

This is a brief introduction on the graduate level to mechanics of various spin relativistic particles with oscillatorlike interaction. This mathematical model proposed by M. Moshinsky could have considerable physical applications for describing processes mediated by tensor fields and in bound state theory.

Valeri V. Dvoeglazov

The Majorana discernment of neutrality is applied to the solutions of $j=1$ Weinberg equations in the $(j,0)\oplus (0,j)$ representation of the Poincarè group.

Valeri V. Dvoeglazov

We analyze dispersion relations of the equations recently proposed by Ahluwalia for describing neutrino. Equations for type-II spinors are deduced on the basis of the Wigner rules for left- and right- 2-spinors and the Ryder-Burgard relation. It is shown that equations contain acausal solutions which are similar to those of the Dirac-like second-order equati

Eric D&#39;Hoker, I. M. Krichever, D. H. Phong

We calculate the effective prepotentials for N=2 supersymmetric SO(N_c) and Sp(N_c) gauge theories, with an arbitrary number of hypermultiplets in the defining representation, from restrictions of the prepotentials for suitable N=2 supersymmetric gauge theories with unitary gauge groups. (This extends previous work in which the prepotential for N=2 supersymm

Valeri V. Dvoeglazov

In the first part of this paper we review several formalisms which give alternative ways for describing the light. They are: the formalism `baroque&#39; and the Majorana-Oppenheimer form of electrodynamics, the Sachs&#39; theory of Elementary Matter, the Dirac-Fock-Podol&#39;sky model, its development by Staruszkiewicz, the Evans-Vigier ${\bf B}^{(3)}$ field

Valeri V. Dvoeglazov

Results of the work of S. Bruce [{\it Nuovo Cimento} {\bf 110}B (1995) 115] are compared with those of recent papers of D. V. Ahluwalia and myself, devoted to describing neutral particles of spin $j=1/2$ and $j=1$.

Valeri V. Dvoeglazov

We present another concrete realization of a quantum field theory, envisaged many years ago by Bargmann, Wightman and Wigner. Considering the special case of the $(1/2,0)\oplus (0,1/2)$ field and developing the Majorana-McLennan-Case-Ahluwalia construct for neutrino we show that fermion and its antifermion can have same intrinsic parities. The construct can

S. James Gates, Sergei M. Kuzenko, Alexander G. Sibiryakov

We present N=2 supersymmetry transformations, both in N=1, D=4 Minkowski and anti-de Sitter superspaces, for higher superspin massless theories. It is noted that the existence of dual versions of massless supermultiplets with arbitrary superspin s may provide a basis for understanding duality in N=1, D=4 superstring theory. We further conjecture that the N=1

Gary McCartor

I shall recall a number of solutions to the Schwinger model in different gauges, having different boundary conditions and using different quantization surfaces. I shall discuss various properties of these solutions emphasizing the degrees of freedom necessary to represent the solution, the way the operator products are defined and the effects these features

S. A. Pernice, G. Oleaga

The mechanism underlying the divergence of perturbation theory is exposed. This is done through a detailed study of the violation of the hypothesis of the Dominated Convergence Theorem of Lebesgue using familiar techniques of Quantum Field Theory. That theorem governs the validity (or lack of it) of the formal manipulations done to generate the perturbative

S. Deser

We present a brief review of some recent results on conformal anomalies in four and more dimensions. The discussion is intended for relativists, so some background on the quantum origin of anomalies and of their simple properties in D=2 is also provided. Topics treated include a critical review of the effective gravitational action uniqueness problem and the

Kimyeong Lee

The self-dual systems are constrained and so are simpler to understand. In recent years there have been several studies on the self-dual Chern-Simons systems. Here I present a brief survey of works done by my collaborators and myself. I also discuss several questions related to these self-dual models.

Conor Houghton, Paul Sutcliffe

We consider 3-monopoles symmetric under inversion symmetry. We show that the moduli space of these monopoles is an Atiyah-Hitchin submanifold of the 3-monopole moduli space. This allows what is known about 2-monopole dynamics to be translated into results about the dynamics of 3-monopoles. Using a numerical ADHMN construction we compute the monopole energy d

S. L. Lyakhovich, A. A. Sharapov, K. M. Shekhter

Massive spinning particle in $6d$-Minkowski space is described as a mechanical system with the configuration space $R^{5,1} \times CP^3$. The action functional of the model is unambiguously determined by the requirement of identical (off-shell) conservation for the phase-space counterparts of three Casimir operators of Poincaré group. The model proves to be

Hidenori Sonoda

As is well known, one can arrange the parameters of the O(N) non-linear sigma model to reproduce the low energy S-matrix elements of the renormalizable O(N) linear sigma model. In this note we provide details which are necessary in order to obtain the off-shell equivalence between the two theories.

K. D. Rothe, F. G. Scholtz, A. N. Theron

The existence of several nilpotent Noether charges in the decoupled formulation of two-dimensional gauge theories does not imply that all of these are required to annihilate the physical states. We elucidate this matter in the context of simple quantum mechanical and field theoretical models, where the structure of the Hilbert space is known. We provide a sy

M. Quiros

In these lectures we present a brief review of the Higgs boson sector in the ``Standard Model&#39;&#39;, and its Minimal Supersymmetric Extension, with particular emphasis on the main mechanisms for Higgs production and decay at LEP2 and LHC, and theoretical bounds on the Higgs boson masses. In the ``Standard Model&#39;&#39; the effective potential can devel

A. Nyffeler, A. Schenk

For large values of the Higgs mass the low energy structure of the gauged linear sigma model in the spontaneously broken phase can adequately be described by an effective field theory. We present a manifestly gauge-invariant functional technique to explicitly evaluate the corresponding effective Lagrangian from the underlying theory.

Boris Kopeliovich

We consider deep-inelastic lepton scattering, Drell-Yan lepton pair and heavy quark production in the reference frame of the target. These reactions traditionally treated as hard have, however, a substantial leading twist soft contribution. One of the manifestations of such a soft component, nuclear shadowing, is overviewed.

S. J. Brodsky, A. Hebecker, E. Quack

The cross section for Drell-Yan pair production in the limit of small $x$-target is derived in the rest frame of the target hadron. Our calculation is based on the fundamental quantity $σ(ρ)$, the cross section for the scattering of a $q\bar{q}$-pair with fixed transverse separation $ρ$ off a hadronic target. As in deep inelastic scattering the result can be

Stephane Keller, Eric Laenen

We extend the phase space slicing method to allow for heavy quarks and fragmentation functions. The method can be used to calculate differential cross section in which any particular particle (massive or massless) is tagged.

Walter T. Giele, Stephane Keller

We present an alternate method to measure $M_W$ at the Tevatron with high luminosity from a direct comparison of the $W$ and $Z$ distributions.

Adam F. Falk

I discuss a variety of issues in the physics of excited bottom and charmed hadrons. Recent developments in spectroscopy, strong decays, and production in fragmentation and weak decays are reviewed.

P. J. Rijken, W. L. van Neerven

The order α_s^2 contributions to the coefficient functions corresponding to the asymmetric fragmentation function $F_A(x,Q^2)$ in $e^+e^-$ annihilation are calculated. From this calculation we infer that the order $(α_s/4π)^2$ correction to the flavour asymmetry sum rule is non vanishing and amounts to $-12β_0C_Fζ(3)$. We also study the effect of the higher

P. J. Rijken, W. L. van Neerven

We present the calculation of the order $α_s^2$ corrections to the coefficient functions contributing to the longitudinal ($F_L(x,Q^2)$) and transverse fragmentation functions ($F_T(x,Q^2)$) measured in electron-positron annihilation. The effect of these higher order QCD corrections on the behaviour of the fragmentation functions and the corresponding longit

Stefan Herrlich

We briefly sketch the calculation of the effective low-energy $|ΔS|=2$-hamiltonian in the next-to-leading order of renormalization group improved perturbation theory. The result for the coefficient $η_3^\star$ is discussed. Further we present a 1996 update of our phenomenological analysis of the unitarity triangle where we include the information available o

M. Le Bellac, C. Manuel

We compute the damping rate of a fermion in a dense relativistic plasma at zero temperature. Just above the Fermi sea, the damping rate is dominated by the exchange of soft magnetic photons (or gluons in QCD) and is proportional to $(E-μ)$, where E is the fermion energy and $μ$ the chemical potential. We also compute the contribution of soft electric photons

George W. S. Hou

From the $0^{++}$ glueball candidate we argue that the $1^{--}$ glueball $O$ to be near in mass to $J/ψ$. This is supported by the recent null search for $ψ^\prime \to ρπ, K^*\bar K$, while absence of distortion in the energy scan of $J/ψ\to ρπ$ indicates that $Γ_O \gg Γ_{J/ψ}$. $O$ may also play a role in the OZI violating $\bar p p \to ϕγ, ϕπ$ production p

H. Gausterer, M. Sammer

Under the hypothesis of no topological structure below a certain scale, we prove that any U(1) lattice configuration corresponds to a classical U(1) gauge field with zero local field strength; i.e. any local representative of the pullback connection one-form is a pure gauge and the local curvature two-form is thus identical zero. The topological information

R. Rylko

We analyze the possibility of studying the heavy flavour hadroproduction properties at the HERA-B experiment. In addition to the high statistics single inclusive B spectra measurements, the measurement of the BBbar meson correlations is considered. The techniques of momentum estimators, widely used in the charm sector, are demonstrated to be useful for the B

F. Abe

We have used 106 pb^-1 of data collected in proton-antiproton collisions at sqrt(s)=1.8 TeV by the Collider Detector at Fermilab to measure jet angular distributions in events with two jets in the final state. The angular distributions agree with next to leading order (NLO) predictions of Quantum Chromodynamics (QCD) in all dijet invariant mass regions. The

Ll. Bel

We present a new approach to the theory of static deformations of elastic test bodies in general relativity based on a generalization of the concept of frame of reference which we identify with the concept of quo-harmonic congruence. We argue on the basis of this new approach that weak gravitational plane waves do not couple to elastic bodies and therefore t

Yasunori Fujii

Cosmological solutions of the Brans-Dicke theory are investigated by including a quantum effect coming from 1-loop correction of matter fields that couple to the scalar field. As the most serious result we face a cosmological ``constant&#39;&#39; in the original conformal frame which is shown to be ``physical&#39;&#39; after a careful analysis of the time va

Reese Harvey, John Zweck

A canonically defined mod 2 linear dependency current is associated to each collection of m sections of a real rank n vector bundle. This current is supported on the linear dependency set of the collection of sections. It is defined whenever the collection satisfies a weak measure theoretic condition called &#34;atomicity&#34;. Essentially any reasonable col

B. Schmittmann, K. E. Bassler

We investigate the effects of quenched disorder on the universal properties of a randomly driven Ising lattice gas. The Hamiltonian fixed point of the pure system becomes unstable in the presence of a quenched local bias, giving rise to a new fixed point which controls a novel universality class. We determine the associated scaling forms of correlation and r

F. B. Anders, D. L. Cox

We consider an Anderson lattice model with a spin 1/2 degenerated conduction electron band and localized ionic CEF-levels, classified according to the irreducible representation of the point group of the lattice. We present the self-consistency equations for local approximations (&#34;$d\rightarrow\infty&#34;$ approximation) for the periodic Anderson model.

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

A symmetrized Density Matrix Renormalization Group procedure together with the correction vector approach is shown to be highly accurate for obtaining dynamic linear and third order polarizabilities of one-dimensional Hubbard and $U-V$ models. The $U-V$ model is seen to show characteristically different third harmonic generation response in the CDW and SDW p

Robert A. Wickham, Gene F. Mazenko

The gaussian closure approximation previously used to study the growth kinetics of the non-conserved O(n) model is shown to be the zeroth-order approximation in a well-defined sequence of approximations composing a more elaborate theory. This paper studies the effects of including the next non-trivial correction in this sequence for the case n=2. The scaling

J. Gonzalez, J. V. Alvarez

We study the strong coupling regime of the $t-t&#39;$ Hubbard model,filled up to the level of the van Hove singularities, by means of an exact diagonalization approach. We characterize the different phases of the model by the different sectors of the Hilbert space with given quantum numbers. By looking for the ground state of the system, we find essentially

Louis Taillefer, Brett Ellman, Benoit Lussier, Mario Poirier

We have used thermal conduction and transverse sound attenuation to probe the anisotropy of the gap structure in two superconducting phases of UPt$_3$. For the low-temperature phase B, transverse sound has in the past provided strong evidence for a line node in the basal plane. Now, from the anisotropy of the thermal conductivity we further establish the pre

A. Polimeni, A. Patanè, M. Grassi Alessi, M. Capizzi

Low temperature photoluminescence and photoluminescence excitation measurements have been performed in a set of InGaAs/GaAs samples with different indium molar fraction, well width, growth conditions and post-growth treatment. This has allowed to change in a controlled way the degree and source of disorder in the samples, thus resulting in an excitonic absor

Avraham Schiller, Kevin Ingersent

A generalized Anderson model for a magnetic impurity in an interacting one-dimensional electron gas is studied via a mapping onto a classical Coulomb gas. For weak potential scattering, the local-moment parameter regime expands as repulsive bulk interactions become stronger, but the Kondo scale for the quenching of the impurity moment varies nonmonotonically

V. I. Anisimov, I. S. Elfimov, M. A. Korotin, K. Terakura

The electronic structure of the doped manganites Pr$_{1-x}$Ca$_x$MnO$_3$ was calculated by the LSDA+U method which takes into account the local Coulomb interaction between d-electrons of transition metal ions. In contrast to the standard local spin density approximation (LSDA) no Jahn-Teller lattice distortions are needed to reproduce the experimentally obse

H. Meyer, J. -C. Anglès d&#39;Auriac, J. -M. Maillard

A connection between integrability properties and general statistical properties of the spectra of symmetric transfer matrices of the asymmetric eight-vertex model is studied using random matrix theory (eigenvalue spacing distribution and spectral rigidity). For Yang-Baxter integrable cases, including free-fermion solutions, we have found a Poissonian behavi

Mikhail A. Skvortsov

The problem of a massive elastic string depinning from a linear defect under the action of a small driving force is considered. To exponential accuracy the decay rate is calculated with the help of the instanton method; then, fluctuations of the quasiclassical solution are taken into account to determine the preexponential factor. The decay rate exhibits a k

D. van der Marel, A. Tsvetkov

We discuss the possible existance of transverse optical plasma modes in superlattices consisting of Josephson coupled superconducting layers. These modes appear as resonances in the current-current correlation function, as opposed to the usual plasmons which are poles in the density-density channel. We consider both bilayer superlattices, and single layer la

Hideo Yoshioka, Yoshikazu Suzumura

We study possible states at low temperatures by applying the renormalization-group method to two chains of Tomonaga-Luttinger liquids with both repulsive intrachain interactions and interchain hopping. As the energy decreases below the hopping energy, three distinct regions I, III, and II appear successively depending on properties of fluctuations. The cross

Subir Sachdev, N. Read

Recent work on the zero temperature phases and phase transitions of strongly random electronic system is reviewed. The transition between the spin glass and quantum paramagnet is examined, for both metallic and insulating systems. Insight gained from the solution of infinite range models leads to a quantum field theory for the transition between a metallic q

Gang Su

By making use of known exact results and symmetry properties for the one-band Hubbard model, we show in a somewhat exact manner that there is no phase separation on a square lattice at arbitrary fillings at finite temperature for both attractive and repulsive on-site Coulomb interaction. This result is consistent with the quantum Monto Carlo calculation.

Jan Wilhelm, Erwin Frey

We calculate the distribution function of the end--to--end distance of a semiflexible polymer with large bending rigidity. This quantity is directly observable in experiments on single semiflexible polymers (e.g., DNA, actin) and relevant to their interpretation. It is also an important starting point for analyzing the behavior of more complex systems such a

Youngkyun Jung, In-mook Kim, Yup Kim

Based on dynamical renormalization group (RG) calculations to the one-loop order, the surface growth described by a nonlinear stochastic conserved growth equation, {\partial h \over \partial t} = \pm ν_2 \nabla^2 h + λ\nabla \cdot (\nabla h)^3 + η, is studied analytically. The universality class of the growth described by the above equation with +{ν_2} (diff

Masahiko Hayashi, Hideo Yoshioka

We discuss the possibility of the ``mixed state&#39;&#39; in incommensurate charge density waves with three-dimensional order. It is shown that the mixed state can be created by applying an electric field perpendicular to the chains. This state consists of topological dislocations induced by the external field and is therefore similar to the mixed states of

D. N. Sheng, Z. Y. Weng

We show that wavefunctions in a two-dimensional (2D) electron system with spin-orbit coupling can be characterized by a topological quantity--the Chern integer due to the existence of the intrinsic Kramers degeneracy. The localization-delocalization transition in such a system is studied in terms of such a Chern number description, which reproduces the known