June 1996 arXiv papers — page 12

M. Rauch, W. L. W. Sargent, D. S. Womble, T. A. Barlow

We use Keck HIRES spectra of three intermediate redshift QSOs to study the physical state and kinematics of the individual components of CIV selected heavy element absorption systems. Fewer than 8 % of all CIV lines with column densities greater than 10^{12.5} cm^{-2} have Doppler parameters b < 6 km/s. A formal decomposition into thermal and non-thermal mot

Zsolt Frei

A new procedure, designed to remove foreground stars from galaxy profiles is presented. Although several programs exist for stellar and faint object photometry, none of them treat star removal from the images very carefully. I present my attempt to develop such a system, and briefly compare the performance of my software to one of the well known stellar phot

B. Fort, Y. Mellier, M. Dantel-Fort Fort

We analyse the surface density of very faint galaxies at the limit of the sky background noise in the field of the cluster of galaxies Cl0024+1654. The radial variation of their number density in the magnitude bins $B=26-28$ and $I=24-26.5$ displays an (anti)bias magnification effect for $I < 24$ which provides the redshift range of the populations seen in $

P. J. Armitage, M. Livio

We investigate the impact between the gas stream from the inner Lagrangian point and the accretion disk in interacting binaries, using three dimensional Smooth Particle Hydrodynamics simulations. We find that a significant fraction of the stream material can ricochet off the disk edge and overflow towards smaller radii, and that this generates pronounced non

Yannick Lespine, Patrick Petitjean

We present a high spectral resolution optical spectrum of the bright quasar Q~1037-2704. The large number of absorption systems suggests the presence of an intervening supercluster, but the issue remains controversial.\par We demonstrate that the strong CIV system at z=2.08 spanning more than 1500 km/s is made up of narrow components with typical Doppler par

M. S. Marley, D. Saumon, T. Guillot, R. S. Freedman

Theoretical spectra and evolutionary models that span the giant planet--brown dwarf continuum have been computed based on the recent discovery of the brown dwarf, Gliese 229 B. A flux enhancement in the 4--5 micron window is a universal feature from Jovian planets to brown dwarfs. We confirm the existence of methane and water in Gl 229 B&#39;s spectrum and f

Adam Burrows

New insights into the mechanism and character of core--collapse supernova explosions are transforming the approach of theorists to their subject. The universal realization that the direct hydrodynamic mechanism does not work and that a variety of hydrodynamic instabilities can influence the viability of theoretical explosions has ushered in a new era in supe

János Kollár

The aim of the paper is to construct examples of cyclic covers of $CP^m\times CP^n$ which are rationally connected but are not rational. The crucial point turns out to be the study of Del Pezzo surfaces over function fields in positive characteristic.

Clint McCrory, Adam Parusinski

An algebraic version of Kashiwara and Schapira&#39;s calculus of constructible functions is used to describe local topological properties of real algebraic sets, including Akbulut and King&#39;s numerical conditions for a stratified set of dimension three to be algebraic. These properties, which include generalizations of the invariants modulo 4, 8, and 16 o

Victor V. Batyrev, Yuri Tschinkel

We investigate analytic properties of height zeta functions of toric varieties. Using the height zeta functions, we prove an asymptotic formula for the number of rational points of bounded height with respect to an arbitrary line bundle whose first Chern class is contained in the interior of the cone of effective divisors

Rita Pardini

We show that infinitesimal Torelli for $n$-forms holds for abelian covers of algebraic varieties of dimension $n\ge 2$, under some explicit ampleness assumptions on the building data of the cover. Moreover, we prove a variational Torelli result for some families of abelian covers.

Tom Banks

We introduce a notion of quantum hair which completely characterizes the state of a D-brane in perturbative string theory. The hair manifests itself as a phase (more generally a unitary matrix in subspaces of degenerate string eigenstates) in the scattering amplitudes of elementary strings on the D brane. As the separation of the D-brane and the string cente

Liang-Jian Zou, X. G. Gong, Qing-Qi Zheng, C. Y. Pan

The transport and magnetic properties in ferromagnetic manganese-oxide thin films are studied based on the model of the coupling between the mobile d-electrons and the core spins in Mn ions. The spontaneous magnetization and the resistivity are obtained for various magnetic fields and temperature. The resistivity in absence of magnetic field and the magnetor

I. Kh. Zharekeshev, M. Batsch, B. Kramer

We investigate numerically the statistical properties of spectra of two-dimensional disordered systems by using the exact diagonalization and decimation method applied to the Anderson model. Statistics of spacings calculated for system sizes up to 1024 $\times$ 1024 lattice sites exhibits a crossover between Wigner and Poisson distributions. We perform a sel

J. de Boer, M. B. Halpern

The Virasoro master equation (VME) describes the general affine-Virasoro construction $T=L^{ab}J_aJ_b+iD^a \dif J_a$ in the operator algebra of the WZW model, where $L^{ab}$ is the inverse inertia tensor and $D^a $ is the improvement vector. In this paper, we generalize this construction to find the general (one-loop) Virasoro construction in the operator al

Hitoshi Murayama, Michael E. Peskin

We describe the anticipated experimental program of an e+e- linear collider in the energy range 500 GeV -- 1.5 TeV. We begin with a description of current collider designs and the expected experimental environment. We then discuss precision studies of the W boson and top quark. Finally, we review the range of models proposed to explain the physics of electro

C. B. Muratov

An asymptotic equation of motion for the pattern interface in the domain-forming reaction-diffusion systems is derived. The free boundary problem is reduced to the universal equation of non-local contour dynamics in two dimensions in the parameter region where a pattern is not far from the points of the transverse instabilities of its walls. The contour dyna

Nir J. Shaviv, Arnon Dar

We propose that repeated photoexcitation/ionization of high Z atoms of highly relativistic flows by star light in dense stellar regions followed by emission of decay/recombination photons, which are beamed and boosted to gamma ray energies in the observer frame, produce gamma ray bursts (GRBs). We show that this overlooked mechanism, which is able to convert

Satish D. Joglekar, Bhabani Prssad Mandal

We formulate the WT identity for proper vertices in a simple and compact form $\partial Γ/ {\partial θ} =0 $ in a superspace formulation of gauge theories proposed earlier. We show this WT identity (together with a subsidiary constraint) lead, in transparent way, the superfield superspace multiplet renormalizations formulated earlier (and shown to explain sy

Pierluigi Monaco

The statistical tools needed to obtain a mass function from realistic collapse time estimates are presented. Collapse dynamics has been dealt with in paper I of this series by means of the powerful Lagrangian perturbation theory and the simple ellipsoidal collapse model. The basic quantity considered here is the inverse collapse time F; it is a non-linear fu

Pierluigi Monaco

A new theory for determining the mass function of cosmic structures is presented. It relies on a realistic treatment of collapse dynamics. Gravitational collapse is analyzed in the Lagrangian perturbative framework. Lagrangian perturbations provide an approximation of truncated type, i.e. small-scale structure is filtered out. The collapse time is suitably d

Stephen L. Adler, L. P. Horwitz

It has recently been shown, by application of statistical mechanical methods to determine the canonical ensemble governing the equilibrium distribution of operator initial values, that complex quantum field theory can emerge as a statistical approximation to an underlying generalized quantum dynamics. This result was obtained by an argument based on a Ward i

D. B. Fairlie, I. A. B. Strachan

The algebraic and Hamiltonian structures of the multicomponent dispersionless Benney and Toda hierarchies are studied. This is achieved by using a modified set of variables for which there is a symmetry between the basic fields. This symmetry enables formulae normally given implicitly in terms of residues, such as conserved charges and fluxes, to be calculat

Laszlo E. Szabo

It is argued that quantum logic and quantum probability theory are fascinating mathematical theories but without any relevance to our real world.

A. Y. Shiekh

It is well known that Einstein gravity is non-renormalizable; however a generalized approach is proposed that leads to Einstein gravity {\it after} renormalization. This them implies that at least one candidate for quantum gravity treats all matter on an equal footing with regard to the gravitational behaviour.

B. Machet

I study the scalar representations of the electroweak group of the Standard Model, which is a subgroup of the chiral group U(N)L x U(N)R with N flavours, for N even, with a special emphasis on their chiral properties and on their behaviour by the discrete symmetries P and CP. They exhaust the $2N^2$ scalar and pseudoscalar degrees of freedom of the chiral gr

George M. Fuller, Christian Y. Cardall

Recent determinations of the deuterium abundance, $^2$H/H, in high redshift Lyman limit hydrogen clouds challenge the usual picture of primordial nucleosynthesis based on \lq\lq concordance\rq\rq\ of the calculated light element ($^2$H, $^3$He, $^4$He, $^7$Li) nucleosynthesis yields with the observationally-inferred abundances of these species. Concordance i

Yuri B. Suris

A new integrable lattice system is introduced, and its integrable discretizations are obtained. A Bäcklund transformation between this new system and the Toda lattice, as well as between their discretizations, is established.

Nicolai Reshetikhin, Alexander A. Voronov, Alan Weinstein

In this paper we study associative algebras with a Poisson algebra structure on the center acting by derivations on the rest of the algebra. These structures, which we call Poisson fibred algebras, appear in the study of quantum groups at roots of 1 and related algebras, as well as in the representation theory of affine Lie algebras at the critical level. Po

Alexander Varchenko

It is known that solutions of the Knizhnik-Zamolodchikov differential equations are given by integrals of closed differential forms over suitable cycles. In this paper a quantization of this geometric construction is described leading to solution of the quantized Knizhnik-Zamolodchikov difference equations.

Giovanni Felder, Alexander Varchenko, Vitaly Tarasov

We give an integral representation for solutions of the elliptic quantum Knizhnik-Zamolodchikov-Bernard difference equations, in the case of sl(2). The result is based on a geometric construction of highest weight representations of the elliptic quantum group associated to sl(2). We also obtain Bethe ansatz eigenfunctions for the corresponding integrable sys

Benjamin Enriquez, Edward Frenkel

The equivalence between the approaches of Drinfeld-Sokolov and Feigin-Frenkel to the mKdV hierarchies is established. A new derivation of the mKdV equations in the zero curvature form is given. Connection with the Baker-Akhiezer function and the tau-function is also discussed.

Sarath G. K. Tennakoon, C. David Andereck, John. J. Hegseth, Hermann Riecke

The effect of temporal modulation on traveling waves in the flows in two distinct systems of rotating cylinders, both with broken azimuthal symmetry, has been investigated. It is shown that by modulating the control parameter at twice the critical frequency one can excite phase-locked standing waves and standing-wave-like states which are not allowed when th

P. Wilhelm, H. Arenhoevel

Within a dynamical model, rescattering effects are studied in coherent pion photoproduction on the deuteron in the $Δ$(1232) resonance region. The model consists of a system of coupled equations for the N$Δ$, NN$π$ and NN channels. Pion rescattering leads in general to a significant reduction of total and differential cross sections resulting in a better des

C. B. Dover, A. Gal, J. M. Richard

We discuss some aspects of possible neutron--antineutron oscillations in nuclei. The phenomenon occurs mostly at the surface of nuclei, and hence {\sl i)} is not very sensitive to medium corrections and {\sl ii)} makes use of the antinucleon-nucleus interaction in a region probed by experiments at CERN.

Axel Bender, David Blaschke, Yuri Kalinovsky, Craig D. Roberts

Deconfinement and chiral symmetry restoration are explored in a confining, renormalisable, Dyson-Schwinger equation model of two-flavour QCD. An order parameter for deconfinement is introduced and used to establish that, in the chiral limit, deconfinement and chiral symmetry restoration are coincident at $T_c\approx 150\,$MeV. The transitions are second orde

V. P. Gudkov

The relations between the value of T- and P-violating correlations in neutron scattering and different models of CP violation are discussed. It is shown that a specific structure of CP-odd interactions gives the possibility to obtain the essential information about CP-odd interaction at the quark-gluon level from nuclear experimental data. The up-to-date est

R. I. Eglitis, A. V. Postnikov, G. Borstel

In applying the semiempirical intermediate neglect of differential overlap (INDO) method based on the Hartree-Fock formalism to a cubic perovskite-based ferroelectric material KNbO3, it was demonstrated that the accuracy of the method is sufficient for adequately describing the small energy differences related to the ferroelectric instability. The choice of

Robert Judd, Edward Odell

A well known argument of James yields that if a Banach space $X$ contains $\ell_1^n$&#39;s uniformly then $X$ contains $\ell_1^n$&#39;s almost isometrically. In the first half of the paper we extend this idea to the ordinal $\ell_1$-indices of Bourgain. In the second half we use our results to calculate the $\ell_1$-index of certain Banach spaces. Furthermor

Vladimir Kanovei

We prove that in the Solovay model every OD graph G on reals satisfies one and only one of the following two conditions: (I) G admits an OD colouring by ordinals; (II) there exists a continuous homomorphism of G_0 into G, where G_0 is a certain F_sigma locally countable graph which is not R-OD colourable by ordinals in the Solovay model. If the graph G is lo

R. Banerjee, P. Mukherjee

We study the Galilean symmetry in a nonrelativistic model, recently advanced by Bak, Jackiw and Pi, involving the coupling of a nonabelian Chern-Simons term with matter fields. The validity of the Galilean algebra on the constraint surface is demonstrated in the gauge independent formalism. Then the reduced space formulation is discussed in the axial gauge u

J. Kijowski, G. Rudolph, M. Rudolph

We apply an earlier formulated programme for quantization of nonabelian gauge theories to one-flavour chromodynamics. This programme consists in a complete reformulation of the functional integral in terms of gauge invariant quantities. For the model under consideration two types of gauge invariants occur -- quantities, which are bilinear in quarks and antiq

M I Vysotsky, V A Novikov, L B Okun, A N Rozanov

Contribution to A.D.Sakharov memorial volume. A detailed review of the electroweak radiative corrections to the Z-boson decays in the framework of the Minimal Standard Modelm (MSM) is presented. After a short historical introduction we describe the optimal parametrization of the MSM, especially of the Born approximation, and derive expressions for the one-lo

Ephraim Fischbach

The exchange of massless neutrinos between heavy fermions (e.g. $e,p,n$) gives rise to a long-range 2-body force. It is shown that the analogous many-body force can lead to an unphysically large energy density in white dwarfs and neutron stars. To reduce the energy density to a physically acceptable value, the neutrino must have a {\it minimum mass}, which i

Ephraim Fischbach, Carrick Talmadge

The suggestion in 1986 of a possible gravity-like ``fifth&#34; fundamental force renewed interest in the question of whether new macroscopic forces are present in nature. Such forces are predicted in many theories which unify gravity with the other known forces, and their presence can be detected by searching for apparent deviations from the predictions of N

Isard Dunietz

It is demonstrated that charm is systematically undercounted in various experiments. Via a process of elimination, $B(D^0 \rightarrow K^- π^+ )$ is identified as the culprit. It calibrates essentially all charmed meson production and decay properties, and thus is central to the physics of heavy flavors. We predict it to decrease significantly below currently

M. Kuhlen

Hadron transverse momentum spectra are proposed as a means to probe the underlying partonic dynamics in deep inelastic scattering. The BFKL evolution equation, postulated for small Bjorken-$x$, leads to an enhanced parton emission over the conventional DGLAP ansatz, and can thus be tested.

A. E. Bergan, J. O. Eeg

We have considered the penguin interaction contribution to $K \rightarrow 2 π$ decays. In particular, we have investigated the effect of the momentum dependence of the penguin coefficient. Our analysis is performed within the Chiral Quark Model where quarks are coupled to the pseudoscalar mesons, which means that hadronic matrix elements can be calculated in

F. A. Berends, A. I. Davydychev, V. A. Smirnov

An algorithm to construct analytic approximations to two-loop diagrams describing their behaviour at small non-zero thresholds is discussed. For some special cases (involving two different-scale mass parameters), several terms of the expansion are obtained.

Borut Bajc, Saša Prelovšek, Mitja Rosina

The $γγ\toρ^0ρ^0\to 4 π$ reaction shows a broad peak at 1.5 GeV in the $(J^P,J_z)=(2^+,2)$ channel which has no counterpart in the $ρ^+ρ^-$ channel. This &#34;resonance&#34; is considered as a candidate for a $qq\bar q\bar q$ state in the &#34;s-channel&#34;. We show, however, that it can also be explained by potential scattering of $ρ^0ρ^0$ via the $σ$- exc

Stefan Herrlich

I present the calculation of the QCD short distance coefficient $η_3$ of the $|ΔS|=2$-hamiltonian in the next-to-leading order (NLO) of renormalization group improved perturbation theory. It involves the two-loop mixing of bilocal structures composed of two $|ΔS|=1$ operators into $|ΔS|=2$ operators. The next-to-leading order corrections enhance $η_3$ by 27\

Ewan D. Stewart

I show that a classical scalar potential with $ V&#39;&#39;/V \sim 1 $ can be sufficiently flattened by quantum corrections to give rise to slow-roll inflation. This provides perhaps the simplest way to generate an inflationary potential without fine tuning. The most natural implementation of this idea produces an unviably small spectral index, but, for exam

Krzysztof Kurek

The semi-analytical approach to the model independent leptonic QED corrections to exclusive $ρ^0$ meson leptoproduction (i.e. electron and muon scattering experiments) is presented. The corrections to $ρ^0$ production at large $Q^2$ as well as to $ρ^0$ photoproduction are studied in details. The numerical results are calculated for two different experimental

K. G. Chetyrkin, J. H. Kuehn, M. Steinhauser

The three-loop vacuum polarization function $\Pi(q^2)$ induced by a massive quark is calculated. A comprehensive description of the method is presented. From the imaginary part the ${\cal O}(\alpha_s^2)$ result for the production of heavy quarks $R(s)=\sigma(e^+e^-\to \mbox{hadrons})/\sigma(e^+e^-\to \mu^+\mu^-)$ can be extracted. Explicit formulae separated

Tigran Aivazian

It is shown that well-known Vlasov equation can be derived by adding &#34;hidden&#34; degrees of freedom and subsequent quantization. The Shrodinger equation obtained in this manner coincides (in x-representation) with the kinetic equation for the original dynamical system

N. E. Mavromatos

I discuss a recent analytic proof of bypassing the no-hair conjecture for two interesting (and quite generic) cases of four-dimensional black holes: (i) black holes in Einstein-Yang-Mills-Higgs (EYMH) systems and (ii) black holes in higher-curvature (Gauss-Bonnet (GB) type) string-inspired gravity. Both systems are known to possess black-hole solutions with

Yoshiaki Ohkuwa, Tetsuro Kitazoe

We consider a quantum cosmology with a massless background scalar field $\pb$ and adopt a wave packet as the wave function. This wave packet is a superposition of the WKB form wave functions, each of which has a definite momentum of the scalar field $\pb$. In this model it is shown that to trace the formalism of the WKB time is seriously difficult without in

Liang-Jian Zou, X. G. Gong, Qing-Qi Zheng, C. Y. Pan

The formation of local magnetic moments and its size effect in one- and three-dimension finite systems with magnetic impurity are investigated based on the Anderson hybridizing model in real space. By the exact diagonalization within the self-consistent mean field approximation, it is found that as contrast to that in infinite system, the formation of the lo

Liang-Jian Zou

Temperature-dependence and magnetic field-dependence of the Hall effect and the magnetic property in manganese-oxide thin films are studied. The spontaneous magnetization and the Hall resistivity are obtained for a various of magnetic fields over all the temperature. It is shown that the Hall resistivity in small magnetic field is to exhibit maximum near the

T. V. Shahbazyan, S. E. Ulloa

We study collective and single-particle intersubband excitations in a system of quantum wires coupled via weak tunneling. For an isolated wire with parabolic confinement, the Kohn&#39;s theorem guarantees that the absorption spectrum represents a single sharp peak centered at the frequency given by the bare confining potential. We show that the effect of wea

M. Marsili, A. Maritan, F. Toigo, J. R. Banavar

It is shown that, by imposing reparametrization invariance, one may derive a variety of stochastic equations describing the dynamics of surface growth and identify the physical processes responsible for the various terms. This approach provides a particularly transparent way to obtain continuum growth equations for interfaces. It is straightforward to derive

David R. Nelson, Leo Radzihovsky

A scaling theory of vortex motion in Bose glass superconductors with currents parallel to the common direction of the magnetic field and columnar defects is presented. Above the Bose-glass transition the longitudinal DC resistivity $ρ_{||}(T)\sim (T-T_{BG})^{ν&#39; z&#39;}$ vanishes much faster than the corresponding transverse resistivity $ρ_{\perp}(T)\sim

V. A. Kashurnikov, N. V. Prokof&#39;ev, B. V. Svistunov, I. S. Tupitsyn

By means of exact diagonalization we study the low-energy states of seven electrons in the lowest Landau level which are confined by a cylindric external potential modelling the rest of a macroscopic system and thus controlling the filling factor $ν$. Wigner crystal is found to be the ground state for filling factors between $ ν= 1/3$ and $ ν= 1/5$ provided

Erik Koch

To understand the electronic shell- and supershell-structure in large metal clusters we have performed self-consistent calculations in the homogeneous, spherical jellium model for a variety of different materials. A scaling analysis of the results reveals a surprisingly simple dependence of the supershells on the jellium density. It is shown how this can be

Ch. Brouder, M. Alouani, K. H. Bennemann

An implementation of the multiple-scattering approach to x-ray magnetic circular dichroism (XMCD) in K-edge x-ray absorption spectroscopy is presented. The convergence problems due to the cluster size and the relativistic corrections are solved using an expansion of the Dirac Green function for complex energies up to the second order in 1/$c$. The Fermi ener

Choon-Lin Ho, V. R. Khalilov, Chi Yang

The thermodynamic potential of an ideal nonrelativistic gas of two-dimensional electrons in crossed uniform magnetic and electric fields is constructed. For low temperatures and very weak electric fields, it is shown that the Hall conductance is always quantized at integral multiples of $e^2/h$ over a large range of strong magnetic fields. This could be view

K. Schoenhammer, V. Meden

The theoretical description of interacting fermions in one spatial dimension is simplified by the fact that the low energy excitations can be described in terms of bosonic degrees of freedom. This fermion-boson transmutation (FBT) which lies at the heart of the Luttinger liquid concept is presented in a way which does not require a knowledge of quantum field

N. B. Wilding, K. Binder

We consider the application of finite-size scaling methods to isothermal-isobaric (constant-NpT) simulations of pure continuum fluids. A finite-size scaling ansatz is made for the dependence of the relevant scaling operators on the particle number. To test the proposed scaling form, constant pressure simulations of the Lennard-Jones fluid at its liquid-vapou

Karl-Peter Marzlin, Juergen Audretsch

The cyclic motion of particles in a periodic potential under the influence of a constant external force is analyzed in an atom optical approach based on Landau-Zener transitions between two resonant states. The resulting complex picture of population transfers can be interpreted in an intuitive diagrammatic way. The model is also applied to genuine atom opti

Reuven Ramaty

Evidence for the existence of low energy cosmic rays in the Galaxy comes from the COMPTEL observations of gamma ray line emission from Orion, and also from light element abundance data which seem to suggest a low energy rather than a relativistic Galactic cosmic ray origin for most of the light elements. The Orion and light isotope data are more consistent w

Luis C. Ho, Alexei V. Filippenko

We present evidence that some of the compact, luminous, young star clusters recently discovered through images taken with the Hubble Space Telescope (HST) have masses comparable to those of old Galactic globular clusters. The &#34;super star cluster&#34; in the center of the nearby amorphous galaxy NGC 1705 has been observed with high dispersion at optical w

G. Bono, F. Caputo, V. Castellani, M. Marconi

We present a theoretical investigation on periods and amplitudes of RR Lyrae pulsators by adopting stellar parameters which cover the range of theoretical evolutionary expectations. Extensive grids of nonlinear, nonlocal and time-dependent convective RR Lyrae envelope models have been computed to investigate the pulsational behavior in both fundamental and f

J. A. Grifols, E. Masso, R. Toldra

A light pseudoscalar coupled to two photons would be copiously emitted by the core of a supernova. Part of this flux would be converted to $γ-$rays by the galactic magnetic field. Measurements on the SN1987A $γ-$ray flux by the Gamma-Ray Spectrometer on the Solar Maximum Mission satellite already imply a bound on the coupling $g < 3 \times 10^{-12}$ GeV$^{-1

Ruediger Kneissl

Statistical comparisons of microwave maps in the GHz range and X-ray maps at around 1 keV are an interesting probe to constrain different astrophysical phenomena. Possible correlations on various angular scales and with different frequency (energy) dependences, although not expected at present day experimental sensitivity, could in principle be due to Galact

Christian Y. Cardall, George M. Fuller

The reported signal at the LSND experiment, when interpreted as neutrino mixing with $δm^2 = 6 \;\rm{eV}^2$, provides evidence for neutrinos with a cosmologically significant mass. However, attempts to reconcile this interpretation of the experiment with other hints about neutrino properties require a (sterile) fourth neutrino and/or an ``inverted&#39;&#39;

E. D. Goldmann, S. R. Renn

Quantum dots in the fractional quantum Hall regime are studied using a Hartree formulation of composite fermion theory. Under appropriate conditions the chemical potential of the dots will oscillate periodically with B due to the transfer of composite fermions between quasi-Landau bands. This effect is analogous to the addition spectrum oscillations which oc

James B. Hartle, Zoltan Perjes

Simplicial geometries are collections of simplices making up a manifold together with an assignment of lengths to the edges that define a metric on that manifold. The simplicial analogs of the Einstein equations are the Regge equations. Solutions to these equations define the semiclassical approximation to simplicial approximations to a sum-over-geometries i

Stephen L. Adler, L. P. Horwitz

We study here the algebraic structure of the conserved generators from which the microcanonical and canonical ensembles are constructed on an underlying generalized quantum dynamics, and the flows they induce on the phase space. We also discuss briefly the structure of the microcanonical and canonical ensembles.

Jon Pumplin

Mass measurements of objects that decay into hadronic jets, such as the top quark, are shown to be improved by using a variant of the $k_t$ jet algorithm in place of standard cone algorithms. The possibility and importance of better estimating the neutrino component in tagged $b$ jets is demonstrated. These techniques will also be useful in the search for Hi

Michael Joyce

The standard requirement for the production of baryons at the electroweak phase transition, that the phase transition be first order and the sphaleron bound be satisfied, is predicated on the assumption of a radiation dominated universe at that epoch. One simple alternative - domination by the energy in a kinetic mode of a scalar field which scales as $1/a^6

E. R. Takano Natti, A. F. R de Toledo Piza

A general time-dependent projection technique is applied to the study of the dynamics of quantum correlations in a system consisting of interacting fermionic and bosonic subsystems, described by the Jaynes-Cummings Hamiltonian. The amplitude modulation of the Rabi oscillations which occur for a strong, coherent initial bosonic field is obtained from the spin

P. Bamert

In this talk I summarize a part of the work done in a recent collaboration with C. Burgess, J. Cline, D. London and E. Nardi \cite{b96}. We analyze the observed discrepancy between $R_b(\equiv\gb /\ghad )$ as measured at LEP and its standard model value for signals of new physics. The focus is thereby put on new physics that manifests itself through heavy qu

Nathan Seiberg

We consider the type I theory compactified on $T^3$. When the D5-brane wraps the $T^3$ it yields a D2-brane in seven dimensions. In the leading approximation the moduli space of vacua of the three dimensional field theory on the brane is $T^4/\ZZ_2$. The dual M theory description of this theory is a compactification on K3 and our 2-brane is the eleven dimens

James M. Cline

I summarize a part of the work done with Bamert, Burgess, London and Nardi (hep-ph/9602438) in which we find simplified expressions for the possible one-loop contributions to the $R_b$ parameter from new virtual particles, including supersymmetric ones. Our expressions make it easier to identify which models and choices of parameters are best able to solve t

Andrew Strominger

The Bekenstein-Hawking entropy for certain BPS-saturated black holes in string theory has recently been derived by counting internal black hole microstates at weak coupling. We argue that the black hole microstate can be measured by interference experiments even in the strong coupling region where there is clearly an event horizon. Extracting information whi

Xavier Martin, Alex Vilenkin

We investigate the spectrum of stochastic gravitational wave background generated by hybrid topological defects: domain walls bounded by strings and monopoles connected by strings. Such defects typically decay early in the history of the universe, and their mass scale is not subject to the constraints imposed by microwave background and millisecond pulsar ob

Preeti Parashar

New deformations of the Poincare group $Fun(P(1+1))$ and its dual enveloping algebra $U(p(1+1))$ are obtained as a contraction of the $h$-deformed (Jordanian) quantum group $Fun(SL_h(2))$ and its dual. A nonstandard quantization of the Heisenberg algebra $U(h(1))$ is also investigated.

Bambi Hu, Jian Zhou

A discrete Frenkel-Kontorova model with two alternate spring constants $k_{1}$ and $k_{2}$ is studied. It is found that this model has many surprising behaviours. The continuum version of this model is different from the sine-Gordon equation, which is the continuum version of the standard FK model. More interestingly, it has an unpinned commensurate phase wh

Arttu K. Rajantie

The two point integrals contributing to the self energy of a particle in a three dimensional quantum field theory are calculated to two loop order in perturbation theory as well as the vacuum ones contributing to the effective potential to three loop order. For almost every integral an expression in terms of elementary and dilogarithm functions is obtained.

Han-Wen Huang, Kuang-Ta Chao

The decay rates of P-wave heavy quarkonia to light hadrons are presented to leading order in $v^2$ and next-to-leading order in $α_s$. They include contributions from both the color-singlet component and the color-octet component of quarkonia. Applying these results to charmonium and using measured decay rates for the $χ_{c1}$ and $χ_{c2}$ by E760, we determ

Ruth Gregory

We examine the possibility that time dependence might remove the singular nature of global string spacetimes. We first show that this time dependence takes a specific form -- a de-Sitter like expansion along the length of the string and give an argument for the existence of such a solution, estimating the rate of expansion. We compare our solution to the sin

A. J. Millis, H. Monien

We derive the expressions needed to interpret experiments relating to interplane magnetic coupling in YBa$_{2}$Cu$_{3}$O$_{6+x}$ and related materials, and use the results to interpret measurements of the optical magnon energy in YBa_{2}Cu_{3}O_{6.2} and of the NMR ``cross-relaxation&#34; rate in Y_2Ba_{4}Cu_{7}O_{15}. We estimate $J_{\perp}\sim 14$ meV in b

G. Barenboim, J. Bernabeu, O. Vives

We explore the sensitivity to a non vanishing neutrino mass offered by dynamical observables, i.e., branching ratios and polarizations. The longitudinal polarization in the C.M. frame decreases by a 4% for $D^+ \rightarrow τ^+ ν_τ$ and $m_{ν_τ}=24$ MeV. Taking advantage of the fact that the polarization is a Lorentz variant quantity, we study the polarizatio

Ryoji Enomoto, Masaharu Tanabashi

We investigate $B^{\pm,0}\rightarrow ρ^0 (ω)h^{\pm,0}$, where $ρ^0 (ω)$ decays to $π^+π^-$ and $h$ is any hadronic final states, such as $π$ or $K$. We find large direct $CP$ asymmetries via $ρ-ω$ interference. A possible determination of the weak phases, such as $ϕ_2={\rm arg}((V_{ud}V^*_{ub})/(V_{td}V^*_{tb}))$ and $ϕ_3={\rm arg}((V_{us}V^*_{ub})/(V_{ts}V^

Dileep P. Jatkar, S. Kalyana Rama

Starting from the type IIB Dirichlet 3-brane action, we obtain a Nambu-Goto action. It is interpreted as the world volume action of a fundamental 3-brane, and its target space theory as F-theory. The target space is twelve dimensional, with signature $(11, 1)$. It is an elliptic fibration over a ten dimensional base space. The $SL(2, Z)$ symmetry of type IIB

Damien M. Pierce, Jonathan A. Bagger, Konstantin T. Matchev, Ren-Jie Zhang

In this paper we compute one-loop corrections to masses and couplings in the minimal supersymmetric standard model. We present explicit formulae for the complete corrections and a set of compact approximations which hold over the unified parameter space associated with radiative electroweak symmetry breaking. We illustrate the importance of the corrections a

Robert B. Griffiths

A system of quantum reasoning for a closed system is developed by treating non-relativistic quantum mechanics as a stochastic theory. The sample space corresponds to a decomposition, as a sum of orthogonal projectors, of the identity operator on a Hilbert space of histories. Provided a consistency condition is satisfied, the corresponding Boolean algebra of

Dominic Mayers

We prove the unconditional security of a quantum key distribution (QKD) protocol on a noisy channel against the most general attack allowed by quantum physics. We use the fact that in a previous paper we have reduced the proof of the unconditionally security of this QKD protocol to a proof that a corresponding Quantum String Oblivious Transfer (String-QOT) p

Lars M. Johansen

We show that no local, hidden variable model can be given for two-channel states exhibiting both a sufficiently high interference visibility and a sufficient degree of anticorrelation in a Mach-Zehnder interferometer.

J. F. Cornwell

Defining conditions for irreducible tensor operators associated with the unitary irreducible corepresentations of compact quantum group algebras are deduced within the framework of the abstract carrier space formalism. It is shown that there are {\em{two}} types of irreducible tensor operator, which may be called `ordinary&#39; and `twisted&#39;. The consist