November 1996 arXiv papers — page 6

Ulrich Bilstein, Birgit Wehefritz

The spectrum of the non-hermitian asymmetric XXZ-chain with additional non-diagonal boundary terms is studied. The lowest lying eigenvalues are determined numerically. For the ferromagnetic and completely asymmetric chain that corresponds to a reaction-diffusion model with input and outflow of particles the smallest energy gap which corresponds directly to t

C. Bulutay, M. Tomak

A quasi-two-dimensional (Q2D) electron liquid (EL) is formed at the interface of a semiconductor heterojunction. For an accurate characterization of the Q2D EL, many-body effects need to be taken into account beyond the random phase approximation. In this theoretical work, the self-consistent static local-field correction known as STLS is applied for the ana

N. S. Branco

Using a real-space renormalization group procedure with no adjustable parameters, we investigate the Blume-Emery-Griffiths model on the square lattice. The formalism respects sublattice symmetry, allowing the study of both signs of K, the biquadratic exchange coupling. Our results for K>0 are compared with other renormalization group calculations and with ex

Robert Benoist, Wilhelm Zwerger

Recent measurements have shown oscillations in the upper critical field of simply connected mesoscopic superconductors. A quantitative theory of these effects is given here on the basis of a Ginzburg-Landau description. For small fields, the $H-T$ phase boundary exhibits a cusp where the screening currents change sign for the first time thus defining a lower

Masanori Ichioka, Nobuhiko Hayashi, Kazushige Machida

Local density of states (LDOS) in the triangular vortex lattice is investigated based on the quasi-classical Eilenberger theory. We consider the case of an isotropic s-wave superconductor with the material parameter appropriate to NbSe_2. At a weak magnetic field, the spatial variation of the LDOS shows cylindrical structure around a vortex core. On the othe

Qisu Zou, Xiaoyi He

Pressure (density) and velocity boundary conditions inside a flow domain are studied for 2-D and 3-D lattice Boltzmann BGK models (LBGK) and a new method to specify these conditions are proposed. These conditions are constructed in consistency of the wall boundary condition based on an idea of bounceback of non-equilibrium distribution. When these conditions

Guy Worthey

Star formation in elliptical galaxies (Es) was and is mostly dominated by mergers and accretions with many suggestive examples seen among local galaxies. Present day star formation in Es is easily measurable in two thirds of Es and appears bursty in character. Direct age determinations from integrated light indicate real age scatter. If one assumes the oldes

M. Tavani, J. E. Grove, W. Purcell, W. Hermsen

We report the results of a CGRO 3-week observation of the binary system containing the 47 ms pulsar PSR B1259-63 orbiting around a Be star companion in a very eccentric orbit. The PSR B1259-63 binary is a unique system for the study of the interaction of a rapidly rotating pulsar with time-variable nebular surroundings. CGRO observed the PSR B1259-63 system

Martin Elvis, Giuseppina Fabbiano

X-ray astronomy needs to set bold, science driven goals for the next decade. Only with defined science goals can we know what to work on, and a funding agency appreciate the need for significant technology developments. To be a forefront science the scale of advance must be 2 decades of sensitivity per decade of time. To be stable to new discoveries these sh

Peter Englmaier, Ortwin Gerhard

We investigate stationary gas flows in a fixed, rotating barred potential. The gas is assumed to be isothermal with an effective sound speed c_s, and the equations of motion are solved with smoothed particle hydrodynamics (SPH). Since the thermal energy in cloud random motions is negligible compared to the orbital kinetic energy, no dependence of the flow on

A. Lindner

A Monte-Carlo study is presented using ground based measurements of the electromagnetic part of showers initiated in the atmosphere by high energetic cosmic rays to reconstruct energy and mass of primary particles with energies above 300 TeV. With two detector arrays measuring Cherenkov light and particle densities as realized in the HEGRA experiment shower

B. Grossan, R. A. Remillard, H. V. Bradt, R. J. V. Brissenden

We present multi-frequency spectra of the Seyfert 1 galaxy H2106-099, from radio to hard X-rays, spanning over a decade of observations. The hard X-ray (2-20 keV) spectrum measured with Ginga had a Log slope of -0.80 +/- 0.02 on 1988 May 18 and -1.02 +/- 0.10 on 1988 May 22 / 23 UT, with no observed flux changes. Other measurements showed variability and unu

Colin A. Norman, Marco Spaans

We study the formation of molecular hydrogen, after the epoch of re-ionization, in the context of canonical galaxy formation theory due to hierarchical clustering. There is an initial epoch of $H_2$ production in the gas phase through the $H^-$ route which ends at a redshift of order unity. Star formation in the protogalactic disks can become self-regulated.

C. S. Reynolds, A. J. Loan, A. C. Fabian, K. Makishima

We present ASCA observations of the nearby galaxies Dwingeloo 1 (Dw1) and Maffei 1 (Mf1). X-ray sources are clearly detected within 3 arcminutes of the optical nuclei of both galaxies. Despite the low Galactic latitude of these fields ($|b|<1\degmark$) we conclude, on probability and spectral grounds, that the detected sources are intrinsic to these galaxies

Vijay Balasubramanian, Robert G. Leigh

We study toroidal compactifications of Type II string theory with D-branes and nontrivial antisymmetric tensor moduli and show that turning on these fields modifies the supersymmetry projections imposed by D-branes. These modifications are seen to be necessary for the consistency of T-duality. We also show the existence of unusual BPS configurations of brane

Martin Cederwall, Alexander von Gussich, Bengt E. W. Nilsson, Per Sundell

We give the full supersymmetric and kappa-symmetric actions for the Dirichlet p-branes, including their coupling to background superfields of ten-dimensional type IIA and IIB supergravity.

Nickolay Y. Gnedin

A possible inconsistency arising when a radiative cooling term is incorporated in a finite resolution self-gravitating hydrodynamic code is discussed. The inconsistency appears when the heating-cooling balance within the cooling and collapsing gas cloud is broken near the resolution limit of a numerical code. As the result, the cooling time of a fluid elemen

J. P. Rodriguez

The two-dimensional quantum ferromagnet filled with a liquid of skyrmions is studied theoretically in the context of the quantum Hall effect near electronic filling factor $ν= 1$. A cross-over between the classical ferromagnetic phase at $ν=1$ and a classical paramagnetic phase at $ν\neq 1$ is obtained, which is consistent with recent Knight-shift measuremen

G. Cynolter, G. Pocsik

Motivated by the fact that the Higgs is not seen, we have proposed a version of the standard model where the scalar doublet is replaced by a vector doublet and its neutral member forms a nonvanishing condensate. Gauge fields are coupled to the new vector fields B in a gauge invariant way leading to mass terms for the gauge fields by condensation. B-particles

John N. Bahcall, Sofia Kirhakos, David H. Saxe, Donald P. Schneider

Observations with the Wide-Field Camera of the Hubble Space Telescope are presented for a representative sample of 20 intrinsically luminous quasars with redshifts smaller than 0.30. These observations show that luminous quasars occur in diverse environments that include ellipticals as bright as the brightest cluster galaxies (2), apparently normal elliptica

S. Roesler, R. Engel, J. Ranft

High energy multiparticle photoproduction off nuclear targets is studied. The photon is assumed to interact in direct scattering processes or as a resolved $q\bar{q}$-state according to the Generalized Vector Dominance Model. In the description of resolved interactions multiple soft and hard processes in each $q\bar{q}$--nucleon interaction are taken into co

E. L. Bratkovskaya, W. Cassing

We present a nonperturbative dynamical study of $e^+e^-$ production in proton-nucleus and nucleus-nucleus collisions from AGS to SPS energies on the basis of the covariant transport approach HSD. For p + Be reactions the dilepton yield for invariant masses $M \leq 1.4$ GeV is found to be dominated by the decays of the $η, ρ, ω$ and $Φ$ mesons at all energies

Jung Kon Kim, Sang Pyo Kim

We study a massive inflaton minimally coupled to the FRW Universe using the semiclassical gravity derived from canonical quantum gravity. It is found that the semiclassical quantum gravity leads to the power-law expansion $t^{2/3}$ in an oscillatory phase of the inflaton. The particle production of the inflaton in the expanding Universe restricts the duratio

W. F. Chen. H. C. Lee, Z. Y. Zhu

We consider quantum holonomy of some three-dimensional general covariant non-Abelian field theory in Landau gauge and confirm a previous result partially proven. We show that quantum holonomy retains metric independence after explicit gauge fixing and hence possesses the topological property of a link invariant. We examine the generalized quantum holonomy de

Philip R. Page

We introduce strong interaction selection rules for the two-body decay and production of hybrid and conventional mesons coupling to two S-wave hybrid or conventional mesons. The rules arise from symmetrization in states in the limit of non-relativistically moving quarks. The conditions under which hybrid coupling to S-wave states is suppressed are determined

A. A. Bytsenko, S. D. Odintsov

The problem of asymptotic density of quantum states of fundamental extended objects is revised in detail. We argue that in the near-extremal regime the fundamental $p$-brane approach can yield a microscopic interpretation of the black hole entropy. The asymptotic behavior of partition functions, associated with the $p$-branes, and the near-extremal entropy o

Matteo G. A. Paris, Alexei V. Chizhov, Ole Steuernagel

A wide class of phase space distributions of a single mode radiation field is shown to be directly accessible to measurement by linear symmetric three-port optical couplers.

Howard M. Wiseman

An atom laser is a hypothetical device which would produce an atomic field analogous to the electromagnetic field of a photon laser. Here I argue that for this analogy to be meaningful it is necessary to have a precise definition of a laser which applies equally to photon or atom lasers. The definition I propose is based upon the principle that the output of

Johan Kustermans, Alfons Van Daele

We associate to an algebraic quantum group a C^*-algebraic quantum group and prove that this C^*-algebraic quantum group satisfies an upcoming definition of Masuda, Nakagami & Woronowicz.

Frank Sander, Thibaut Devolder, Tilman Esslinger, Theodor W. Hansch

We experimentally study the motion of atoms interacting with a periodically pulsed near resonant standing wave. For discrete pulse frequencies we observe a comb-like momentum distribution. The peaks have widths of 0.3 recoil momenta and a spacing which is an integer multiple of the recoil momentum. The atomic population is trapped in ground states which peri

Gerald A. Miller

The experimental discovery that the nucleus is approximately transparent to low energy pions is reviewed. The consequences of this for nuclear deep inelastic scattering and Drell-Yan interactions are discussed. I argue that low energy nucleus data imply that there is little nuclear enhancement of the pion cloud of a nucleon, and try to interpret this in term

D. K. Srivastava, M. G. Mustafa, B. Müller

We investigate the chemical equilibration of the parton distributions in collisions of two heavy nuclei. We use initial conditions obtained from a self-screened parton cascade calculation and, for comparison, from the HIJING model. We consider a one-dimensional, as well as a three-dimensional expansion of the parton plasma and find that the onset of the tran

Tim Hsu

Let $L$ be a Moufang loop which is centrally nilpotent of class 2. We first show that the nuclearly-derived subloop (normal associator subloop) $L^*$ of $L$ has exponent dividing 6. It follows that $L_p$ (the subloop of $L$ of elements of $p$-power order) is associative for $p>3$. Next, a loop $L$ is said to be a {\it small Frattini Moufang loop}, or SFML, i

Falk Rohsiepe

Motivated by the necessity to include so-called logarithmic operators in conformal field theories (Gurarie, 1993) at values of the central charge belonging to the logarithmic series c_{1,p}=1-6(p-1)^2/p, reducible but indecomposable representations of the Virasoro algebra are investigated, where L_0 possesses a nontrivial Jordan decomposition. After studying

I. Krichever

Algebraic-geometrical n-orthogonal curvilinear coordinate systems in a flat space are constructed. They are expressed in terms of the Riemann theta function of auxiliary algebraic curves. The exact formulae for the potentials of algebraic geometrical Egoroff metrics and the partition functions of the corresponding topological field theories are obtained.

Oleg Zaboronsky

A class of quantum field theories invariant with respect to the action of an odd vector field Q on a source supermanifold $Σ$ is considered. We suppose that Q satisfies the conditions under which an integral of any Q-invariant function over $Σ$ localizes to the zero locus of Q. The Q-invariant sector of a field theory from the class above is shown then to be

C. Anastopoulos

In this paper we are interested in the studying coarse-graining in field theories using the language of quantum open systems. Motivated by the ideas of Calzetta and Hu on correlation histories we employ the Zwanzig projection technique to obtain evolution equations for relevant observables in self-interacting scalar field theories. Our coarse-graining operat

C. Anastopoulos

We give an exposition of a technique, based on the Zwanzig projection formalism, to construct the evolution equation for the reduced density matrix corresponding to the n-particle sector of a field theory. We consider the case of a scalar field with a $g ϕ^3$ interaction as an example and construct the master equation at the lowest non-zero order in perturba

A. A. Slavnov

Problems in lattice gauge models with fermions are discussed. A new bosonic Hermitean effective action for lattice QCD with dynamical quarks is presented. In distinction of the previous version, it does not include constraints and is better suited for Monte-Carlo simulations.

Amit Giveon

Some notions in non-perturbative dynamics of supersymmetric gauge theories are being reviewed. This is done by touring through a few examples.

R Delbourgo, D Elliott, D McAnally

The sum of all ladder and rainbow diagrams in $ϕ^3$ theory near 6 dimensions leads to self-consistent higher order differential equations in coordinate space which are not particularly simple for arbitrary dimension D. We have now succeeded in solving these equations, expressing the results in terms of generalized hypergeometric functions; the expansion and

F. Myhrer

From recent charge exchange measurements in the extreme forward direction, an independent and precise determination of the pion nucleon coupling constant is possible. This determination has reopened the debate on the value of this fundamental coupling constant of nuclear physics. Precise measurements of charge exchange observables at forward angles below 900

L. Brücher, J. Franzkowski, A. Frink, D. Kreimer

The program package XLOOPS calculates massive one- and two-loop Feynman diagrams. It consists of five parts: i) a graphical user interface ii) routines for generating diagrams from particle input iii) procedures for calculating one-loop integrals both analytically and numerically iv) routines for massive two-loop integrals v) programs for numerical integrati

A. Capella

In the first part, I give a brief description of the quark-gluon plasma search at CERN and of some experimental results. In the second part, I review a dynamical model of nucleus-nucleus interactions and propose a physical interpretation of those results.

S. Moretti, K. Odagiri

We study integrated and differential rates for the production of charged Higgs bosons $H^\pm$ of the Minimal Supersymmetric Standard Model via b-quark initiated subprocesses in pp collisions at the Large Hadron Collider. In detail, we compute cross sections and distributions of the reactions: $bU \to bDH^+ \to bDτ^+ν_τ\oplus C.C.$ and $bU \to bDH^+ \to bD t\

T. E. Browder

We review recent experimental results on hadronic decays and lifetimes of hadrons containing b and c quarks. We discuss charm counting and the semileptonic branching fraction in B decays, the color suppressed amplitude in B and D decay, and the search for gluonic penguins in B decay.

Rudolph C. Hwa

The critical behavior of quarks undergoing phase transition to hadrons is considered in the framework of the Ising model. It is found that spatial fluctuations do not alter the F-scaling result obtained earlier in the Ginzberg-Landau formalism. For the study of chaos a new measure must be found for the quark-gluon system, for which the usual description appr

Jonathan M Flynn

After a brief discussion of the promise and limitations of the lattice technique, I review lattice QCD results for several quantities of phenomenological interest. These are: matrix elements for heavy-to-light meson decays, leptonic decay constants f_B and f_D, the parameters B_B and B_K for neutral B and K meson mixing respectively, the strong coupling cons

Gerhard K. Mallot

The recently proposed COMPASS experiment at CERN attempts a measurement of the gluon polarisation with a precision of delta(Delta g/g) = 0.1. The experiment uses open charm muoproduction to tag the photon-gluon fusion process.

Michael Kobel, representing the four LEP collaborations ALEPH, DELPHI, L3

Four-fermion production via electroweak neutral currents has been measured by all four LEP collaborations at center-of-mass energies near the Z resonance and for the first time also at energies well above the Z peak. Essentially all possible final states have been covered in four different topologies.

Carlos Pinheiro, Gentil O. Pires, Fernando A. B. Rabelo de Carvalho

We discuss some features of Einstein-Proca gravity in D=3 and 4 space-times. Our study includes a discussion on the tree-level unitarity and on the issue of light deflection in 3D gravity in the presence of a mass term.

M. Bruni, S. Matarrese, S. Mollerach, S. Sonego

We present the results of a study of the gauge dependence of spacetime perturbations. In particular, we consider gauge invariance in general, we give a generating formula for gauge transformations to an arbitrary order n, and explicit transformation rules at second order.

Osamu Iguchi, Hideki Ishihara

We study how the initial inhomogeneities of the universe affect the onset of inflation in the closed universe. We consider the model of a chaotic inflation which is driven by a massive scalar field. In order to construct an inhomogeneous universe model, we use the long wavelength approximation ( the gradient expansion method ). We show the condition of the i

Y. -K. Zhou, M. -T. Batchelor

The analytic, nonlinear integral equation approach is used to calculate the finite-size corrections to the transfer matrix eigen-spectra of the critical dilute O(n) model on the square periodic lattice. The resulting bulk conformal weights extend previous exact results obtained in the honeycomb limit and include the negative spectral parameter regimes. The r

Gerald A. Miller, Larry B. Sorensen

Quantum electrodynamics (qed) is used to derive the differential cross sections measured in the three new experimental internal source ensemble x-ray holographies: bremsstrahlung (BXH), fluorescence (XFH), and multiple-energy (MEXH) x-ray holography. The polarization dependence of the BXH cross section is also obtained. For BXH, we study analytically and num

N. Rajewsky, M. Schreckenberg

We study two common types of time-noncontinuous updates for one dimensional stochastic cellular automata with arbitrary nearest neighbor interactions and arbitrary open boundary conditions. We first construct the stationary states using the matrix product formalism. This construction then allows to prove a general connection between the stationary states whi

A. I. Buzdin, H. Kachkachi

We derive a generalized Ginzburg-Landau (GL) functional near the tricritical point in the (T,H)-phase diagram for the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) superconducting state, in 1,2, and 3 dimensions. We find that the transition from the normal to the FFLO state is of second order in 1 and 2 dimensions, and the order parameter with one-coordinate sine

Fevzi Buyukkilic, Dogan Demirhan, Ugur Tirnakli

In this study, the mean-field Ising model, using the Bogolyubov inequality which has been obtained in the frame of the generalized statistics, has been investigated.

Olle Gunnarsson

Experimental studies of superconductivity properties of fullerides are briefly reviewed. Theoretical calculations of the electron-phonon coupling, in particular for the intramolecular phonons, are discussed extensively. The calculations are compared with coupling constants deduced from a number of different experimental techniques. It is discussed why the A_

G. M. Minkov, O. E. Rut, A. V. Germanenko

We present results of tunneling studies of p-Hg_{1-x}Cd_{x}Te-oxide-Al structures with 0.165<x<0.2 in a magnetic field up to 6 T. The tunneling conductivity oscillations resulting from the Landau quantization of the energy spectrum in the semiconductor volume are investigated. Under an in-plane magnetic field the amplitudes of tunneling conductivity maxima c

K. Imura, N. Nagaosa

We study the effect of backward scatterings in the tunneling at a point contact between the edges of a second level hierarchical fractional quantum Hall states. A universal scaling dimension of the tunneling conductance is obtained only when both of the edge channels propagate in the same direction. It is shown that the quasiparticle tunneling picture and th

E. Aurell, U. Frisch, A. Noullez, M. Blank

It is shown that the inverse Lagrangian map for the solution of the Burgers equation (in the inviscid limit) with Brownian initial velocity presents a bifractality (phase transition) similar to that of the Devil&#39;s staircase for the standard triadic Cantor set. Both heuristic and rigorous derivations are given. It is explained why artifacts can easily mas

Lapo Casetti, Alessandro Macchi

We present a detailed description of how a differential geometric approach to Hamiltonian dynamics can be used for determining the existence of a crossover between different dynamical regimes in a realistic system, a model of a rare gas solid. Such a geometric approach allows to locate the energy threshold between weakly and strongly chaotic regimes, and to

Allan Sandage, G. A. Tammann

The status of the determination of the Hubble constant is reviewed, setting out the evidence for the long distance scale with H_0=55+/-5. In parallel, various precepts said to favor the short distance scale with H_0>70 are discussed. The strongest evidence for the long scale are (1) the calibration of the peak absolute magnitude of type Ia supernovae with th

H. R. Schmitt, A. L. Kinney, T. Storchi-Bergmann, R. Antonucci

We use the radio axis as an indicator of the orientation of the obscuring torus in Seyfert galaxies, and analyze the difference between the position angles of extended radio structures and host galaxy major axis of Seyfert 1 and Seyfert 2 galaxies. We find that Seyfert 1&#39;s are less likely to have extended radio structures along the host galaxy major axis

Zacharias A. M. Protogeros, Adrian L. Melott, Robert J. Scherrer

We test tree-level perturbation theory for Gaussian initial conditions with power spectra $P(k)\propto k^n$ by comparing the probability distribution function (PDF) for the density predicted by the Local Lagrangian Approximation (LLA) with the results of numerical gravitational clustering simulations. Our results indicate that our approximation correctly rep

J. E. Horvath, J. A. de Freitas Pacheco

We report new calculations of the physical properties of a quark-diquark plasma. A vacuum contribution is taken into account and is responsible for the appearance of a stable state at zero pressure and at a baryon density of about 2.2 times the nuclear matter density in this model. The resulting equation of state was used to integrate numerically the Tolman-

Keith A. Olive, Evan Skillman, Gary Steigman

We include new data in an updated analysis of helium in low metallicity extragalactic HII regions with the goal of deriving the primordial abundance of He4 (Y_P). We show that the new observations of Izotov et al (ITL) are consistent with previous data. However they should not be taken in isolation to determine (Y_P) due to the lack of sufficiently low metal

S. J. Desch, W. G. Roberge

We describe an implicit prediction of the accretion disk models constructed by Wardle and Konigl (1990) for the circumnuclear disk (CND) of gas and dust near the Galactic center: supersonic ambipolar diffusion, an essential dynamical ingredient of the Wardle-Konigl disks, will cause the alignment of dust grains due to a process described by Roberge, Hanany,

N. W. Evans, R. M. Häfner, P. T. de Zeeuw

The Jeans equations give the second moments or stresses required to support a stellar population against the gravity field. A general solution of the Jeans equations for arbitrary axisymmetric scale-free densities in flattened scale-free potentials is given. A two-parameter subset of the solution for the second moments for the self-consistent density of the

Wyn Evans

Microlensing has established itself as a powerful new method for the detection of baryonic dark matter in the Galaxy. The theory of microlensing is sketched and its similarity with the optical effect of twinkling is explained. The bulk of the article presents a new analysis of the data-set on microlensing towards the Large Magellanic Cloud. The extent, flatt

G. Tagliaferri, S. Covino, T. A. Fleming, M. Gagnè

We present the analysis of the X-ray data of the young active star HD35850 obtained with ASCA and ROSAT. Our main goal was to see if there is a difference in the elemental abundances of active stars between young and more evolved objects. A two temperature plasma with subsolar abundances, of the order of Z = 0.15 - 0.3, is required to fit the SIS spectra. Si

A. O. Jaunsen, J. Hjorth

The gravitationally lensed quasar B1600+434 (z=1.61, mV=21.6) has been observed at the 2.56m Nordic Optical Telescope (NOT). In this Letter we report the discovery of an edge-on late-type galaxy located between the two lensed components (separation 1\farcs4), close to the fainter image. The galaxy photometry indicates that its redshift is approximately 0.4.

Slavek M. Rucinski

Light curves of the contact systems visible in the direction of Baade&#39;s Window have been analyzed using the first coefficients of the Fourier representation. The results confirm that the geometric contact between components is usually weak. Systems showing significant differences in the depths of eclipses are very rare in the volume-limited sample to 3 k

Andrew Gould, John N. Bahcall, Chris Flynn

We analyze the disk M dwarfs found in 31 new fields observed with the Wide Field Camera (WFC2) on the Hubble Space Telescope (HST) together with the sample previously analyzed from 22 WFC2 fields and 162 prerepair Planetary Camera (PC1) fields. The new observations, which include the 28 high-latitude fields comprising the Large Area Multi-Color Survey (``Gro

Mareki Honma, Yoshiaki Sofue

Using an outer rotation curve of the Galaxy, we explore the galactic constants and the mass of the Galaxy. We show that Θ_0 of 200 km/s is more favorable than the IAU standard value of 220 km/s, and also show that if Θ_0 is smaller than 207 km/s the rotation curve beyond 2R_0 is declining in Keplerian fashion. In the case of Θ_0= 200 km/s and R_0= 7.6 kpc, t

S. Michael Fall

We outline a method to infer the global history of star formation in galaxies with input only from absorption-line observations of quasars. The application of the method to existing data leads to the conclusion that most stars formed at relatively low redshifts (z <~ 2). We combine the global rate of star formation with stellar population synthesis models to

Taoling Xie

We further discuss the suggestion that the chemistry in a photon-dominated region is coupled to that in the UV-shielded region behind it by turbulent t ransport processes. In addition to transport time-scales, we discuss why MHD waves/turbulence will likely cause transport instead of prohibiting it.

Taoling Xie

Under the basic assumption that the observed turbulent motions in molecular clouds are Alfvenic waves or turbulence, we emphasize that the Doppler broadening of molecular line profiles directly measures the velocity amplitudes of the waves instead of the Alfven velocity. Assuming an equipartition between the kinetic energy and the Alfvenic magnetic energy, w

K. Y. Lo, Yu Gao, Robert A. Gruendl

Arp 302, a luminous infrared source (L_{IR} = 4.2x10^{11} Lsun), consisting of two spiral galaxies (VV340A and VV340B) with nuclear separation of 40&#39;&#39;, has the highest CO luminosity known. Observations with the BIMA array at 5&#39;&#39; X 7&#39;&#39; resolution reveal that the CO emission is extended over 23.0 kpc in the edge-on spiral galaxy, VV340A

Randi L. Cohen, Puragra Guhathakurta, Brian Yanny, Donald P. Schneider

To probe the nature of stellar evolution in dense environments, we study the dense core of the globular cluster Messier 13 using pre-refurbishment Planetary Camera-I images obtained with the Hubble Space Telescope. We find 15 blue straggler star candidates and 10 other possible blue stragglers in this region of M13. Their specific frequency is in the range 0

Ivanio Puerari, Horacio Dottori

Shock induced star formation in a stellar density wave scenario produces an azimuthal gradient of ages across the spiral arms which has opposite signs on either side of the corotation resonance (CR). We present a method based on the Fourier analysis of azimuthal profiles, to locate the CR and determine the arm character (trailing or leading) in spiral galaxi

Bo Ilic, J. M. Landsberg

Let X be a nonsingular simply connected projective variety of dimension m, E a rank n vector bundle on X, and L a line bundle on X. Suppose that $S^2(E^{*}) \otimes L$ is an ample vector bundle and that there is a constant even rank $r \ge 2$ symmetric bundle map $E \to E^{*} \otimes L$. We prove that $m \le n-r$. We use this result to solve the constant ran

Massimiliano Mella

A normal projective variety X is called Fano if a multiple of the anticanonical Weil divisor, -K_X, is an ample Cartier divisor, the index of a Fano variety is the number i(X):=sup{t: -K_X= tH, for some ample Cartier divisor H}. Mukai announced, the classification of smooth Fano manifolds X of index i(X)=n-2, under the assumption that the linear system |H| c

Pierre Binetruy, Mary K. Gaillard, Yi-Yen Wu

Using the linear multiplet formulation for the dilaton superfield, we construct an effective lagrangian for hidden-sector gaugino condensation in string effective field theories with arbitrary gauge groups and matter. Nonperturbative string corrections to the Kähler potential are invoked to stabilize the dilaton at a supersymmetry breaking minimum of the pot

D. Simonian, S. V. Kravchenko, M. P. Sarachik

We report a remarkable symmetry between the resistivity and conductivity on opposite sides of the B=0 metal-insulator transition in a two-dimensional electron gas in high-mobility silicon MOSFET&#39;s. This symmetry implies that the transport mechanisms on the two sides are related.

Gregory Mahlon, Stephen Parke

We show in single top quark production that the spin of the top quark is correlated with the direction of the d-type quark in the event. For single top production in the W* channel, the d-type quark comes dominantly from the antiproton at the Tevatron, whereas for the W-gluon fusion channel the spectator jet is the d-type quark the majority of the time at th

A. Sorin

A few new N=2 superintegrable mappings in the (1|2) superspace are proposed and their origin is analyzed. Using one of them, acting like the discrete symmetry transformation of the N=2 supersymmetric modified NLS hierarchy, the recursion operator and hamiltonian structures of the hierarchy are constructed.

Dmitri Melikhov

Semileptonic decays $D\to K,K^*,π,ρ$, $D_s\to η,η&#39;,ϕ$, and $B\to D,D^*,π,ρ$ are analyzed within the dispersion formulation of the quark model. The form factors at timelike $q$ are derived by the analytical continuation from spacelike $q$ in the form factors of the relativistic light--cone quark model. The resulting double spectral representations allow a

P. J. Mulders

I discuss inclusive and semi-inclusive lepton-hadron scattering emphasizing the importance of polarization in order to study various single or double spin asymmetries and the importance of particle identification and angular resolution in the dectection of final state particles to study azimuthal asymmetries. The observables obtained in this way enable a det

I. Antoniadis, P. O. Mazur, E. Mottola

We present a simple argument which determines the critical value of the anomaly coefficient in four dimensional conformal factor quantum gravity, at which a phase transition between a smooth and elongated phase should occur. The argument is based on the contribution of singular configurations (&#34;spikes&#34;) which dominate the partition function in the in

Yoshiaki Sofue

We have derived rotation curves of nearby galaxies, which are almost completely sampled from the inner to outer regions. We used high-resolution position-velocity diagrams in the CO line along the major axes for the inner regions, and HI-line data for the outer regions. We combined the CO and HI data to obtain total rotation curves from the nuclear to outer

Hoi-Kwong Lo

It had been widely claimed that quantum mechanics can protect private information during public decision in for example the so-called two-party secure computation. If this were the case, quantum smart-cards could prevent fake teller machines from learning the PIN (Personal Identification Number) from the customers&#39; input. Although such optimism has been

Peter Kopietz, Guillermo E. Castilla

We calculate the effect of infrared fluctuations of the Chern-Simons gauge field on the single-particle Green&#39;s function of composite fermions in the half-filled Landau level via higher-dimensional bosonization on a curved Fermi surface. We find that composite fermions remain well-defined quasi-particles, with an effective mass given by the mean-field va

Haye Hinrichsen, Sven Sandow

We study a one-dimensional anisotropic exclusion model describing particles moving deterministically on a ring with a single defect across which they move with probability 0 < q < 1. We show that the stationary state of this model can be represented as a matrix-product state.

V. A. Miransky, Koichi Yamawaki

The conception of the conformal phase transiton (CPT), which is relevant for the description of non-perturbative dynamics in gauge theories, is introduced and elaborated. The main features of such a phase transition are established. In particular, it is shown that in the CPT there is an abrupt change of the spectrum of light excitations at the critical point

Yongbin Ruan

We use virtual neighborhood technique to establish GW-invariants, Quantum cohomology, equivariant GW-invariants, equivariant quantum cohomology and Floer cohomology for general symplectic manifold. We also establish GW-invariants for a family of symplectic manifolds. As a consequence, we prove Arnold conjecture for nondegenerate Hamiltonian symplectomorphism

N. J. Cerf, C. Adami

The amount of information that can be accessed via measurement of a quantum system prepared in different states is limited by the Kholevo bound. We present a simple proof of this theorem and its extension to sequential measurements based on the properties of quantum conditional and mutual entropies. The proof relies on a minimal physical model of the measure

Martin Schlichenmaier

This talk reports on results on the deformation quantization (star products) and on approximative operator representations for quantizable compact K&#34;ahler manifolds obtained via Berezin-Toeplitz operators. After choosing a holomorphic quantum line bundle the Berezin-Toeplitz operator associated to a differentiable function on the manifold is the operator

R. Delbourgo, R. B. Zhang

The problem of how to obtain quasi-classical states for quantum groups is examined. A measure of quantum indeterminacy is proposed, which involves expectation values of some natural quantum group operators. It is shown that within any finite dimensional irreducible representation, the highest weight vector and those unitarily related to it are the quasi-clas