August 1999 arXiv papers — page 15

Edward Shipwash

A method is described where the aminoacyl-tRNA synthetase system is used to create very small devices for quantitative analysis of the amino acids that occur in proteins. The basis of the method is that each of the 20 synthetases and/or a tRNA specific for a different amino acid is separated spatially (e.g. in tiny chambers or on a surface). The reactions ca

V. E. Moiseenko, V. V. Pilipenko

A new method for numerical solving of boundary problem for ordinary differential equations with slowly varying coefficients which is aimed at better representation of solutions in the regions of their rapid oscillations or exponential increasing (decreasing) is proposed. It is based on approximation of the solution to find in the form of superposition of cer

M. M. Crum

Crum's seminal result of 1955 is archived here

Gerald A. Miller

A brief introduction to light front techniques is presented. This is followed by a review of recent attempts to perform realistic, relativistic nuclear physics with those techniques.

C. W. Johnson, G. F. Bertsch, D. J. Dean, I. Talmi

We investigate the generic pairing properties of shell-model many-body Hamiltonians drawn from ensembles of random two-body matrix elements. Many features of pairing that are commonly attributed to the interaction are in fact seen in a large part of the ensemble space. Not only do the spectra show evidence of pairing with favored J=0 ground states and an ene

A. Bonasera

We discuss properties of quark matter at finite baryon densities and zero temperature in a Vlasov approach. We use a screened interquark Richardson's potential consistent with the indications of Lattice QCD calculations. We analyze the choices of the quark masses and the parameters entering the potential which reproduce the binding energy (B.E.) of infin

N. V. Shevchenko, V. B. Belyaev, S. A. Rakityansky, S. A. Sofianos

Elastic eta-d scattering is considered within the Alt-Grassberger-Sandhas (AGS) formalism for various eta-N input data. A three-body resonant state is found close to the eta-d threshold. This resonance is sustained for different choices of the two-body eta-N scattering length a_{ηN}. The position of the resonance moves towards the eta-d threshold when Re a_{

L. P. Csernai, D. Roehrich

A review of earlier fluid dynamical calculations with QGP show a softening of the directed flow while with hadronic matter this effect is absent. The effect shows up in the reaction plane as enhanced emission which is orthogonal to the directed flow. Thus, it is not shadowed by the deflected projectile and target. As both of these flow components are in the

A. N. Leznov

Generators of the quantum $SU_q(2)$ algebra are obtained in the explicit form in the basis where the operator $\exp {J_z\over 2} J_x \exp {J_z\over 2}$ is diagonal. It is shown that the solution of this problem is related to the representation theory of the two-dimensional algebra $[s,r]=\tanh t (s^2-r^2+1)$. The relevance of such basis to some problems of q

A. N. Leznov

It is shown that the Monge equation is equivalent to the ordinary differential equation $\ddot X=0$ of free motion. Equations of Monge type (with their general solutions) are connected with each ordinary differential equation of second order $\ddot X=F(\dot X,X; t)$, integrable by quadratures. The result is generalised to a system of equations of the second

A. N. Leznov

The $2n$ dimensional manifold with two mutually commutative operators of differentiation is introduced. Nontrivial multidimensional integrable systems connected with arbitrary graded (semisimple) algebras are constructed. The general solution of them is presented in explicit form.

Carl R. Seaquist

This paper constructs a continuous decomposition of the Sierpiński curve into acyclic continua one of which is an arc. This decomposition is then used to construct another continuous decomposition of the Sierpiński curve. The resulting decomposition space is homeomorphic to the continuum obtained from taking the Sierpiński curve and identifying two points on

Marc A. A. van Leeuwen

The conjugacy classes of nilpotent $n\times n$ matrices can be parametrised by partitions $λ$ of $n$, and for a nilpotent $η$ in the class parametrised by $λ$, the variety $F_η$ of $η$-stable flags has its irreducible components parametrised by the standard Young tableaux of shape $λ$. We indicate how several algorithmic constructions defined for Young table

J. M. Landsberg, L. Manivel

We connect the algebraic geometry and representation theory associated to Freudenthal's magic square. We give unified geometric descriptions of several classes of orbit closures, describing their hyperplane sections and desingularizations, and interpreting them in terms of composition algebras. In particular, we show how a class of invariant quartic poly

Micho Durdevich

Quantum affine bundles are quantum principal bundles with affine quantum structure groups. A general theory of quantum affine bundles is presented. In particular, a detailed analysis of differential calculi over these bundles is performed, including the description of a natural differential calculus over the structure affine quantum group. A particular atten

Piotr Pragacz

Let V be a 2n-dimensional complex symplectic space. Let G' be the Lagrangian Grassmannian of maximal isotropic subspaces of V embedded via the inclusion i into the Grassmannian G of all n-dimensional subspaces of V. We discuss the restriction via i* of a Schubert class from H(G), as an integral linear combination of Schubert classes in H(G'). Among t

Terry Gannon

In these notes, based on lectures given in Istanbul, we give an introduction both to Monstrous Moonshine and to the classification of rational conformal field theories, using this as an excuse to explore several related structures and go on a little tour of modern math. We will discuss Lie algebras, modular functions, the finite simple group classification,

Alain Lascoux, Piotr Pragacz

We give closed-form formulas for the fundamental classes of degeneracy loci associated with vector bundle maps given locally by (not necessary square) matrices which are symmetric (resp. skew-symmetric) w.r.t. the main diagonal. Our description uses essentially Schur Q-polynomials of a bundle, and is based on a certain push-forward formula for these polynomi

Mike Zabrocki

We present two symmetric function operators $H_3^{qt}$ and $H_4^{qt}$ that have the property $H_{3}^{qt} H_{(2^a1^b)}[X;q,t] = H_{(32^a1^b)}[X;q,t]$ and $H_4^{qt} H_{(2^a1^b)}[X;q,t] = H_{(42^a1^b)}[X;q,t]$. These operators are generalizations of the analogous operator $H_2^{qt}$ and also have expressions in terms of Hall-Littlewood vertex operators. We also

V. E. Rochev

A mechanism for the dynamical mass generation of a non-Abelian gauge field which is based on taking into account the contributions of the gauge field vacuum configurations into the formation of the physical vacuum is considered. For a model of the physical vacuum as a superposition of Abelian configurations the gauge field propagator is calculated in the lea

Atish Dabholkar, Sandip P. Trivedi

We investigate Yang-Mills theory on a spatial torus at finite temperature in the presence of discrete electric and magnetic fluxes using the AdS/CFT correspondence. We calculate the leading dependence of the partition function on the fluxes using the dual supergravity theory and comment upon the interpretation of these fluxes as discrete quantum hair for bla

Joseph Lykken, Lisa Randall

In a nontrivial background geometry with extra dimensions, gravitational effects will depend on the shape of the Kaluza-Klein excitations of the graviton. We investigate a consistent scenario of this type with two positive tension three-branes separated in a five-dimensional Anti-de Sitter geometry. The graviton is localized on the ``Planck'' brane,

V. P. Gusynin, V. A. Miransky, I. A. Shovkovy

The theory of the magnetic catalysis of chiral symmetry breaking in QED is developed. An approximation for the Schwinger-Dyson equations describing reliably this phenomenon is established, i.e., it is shown that there exists a consistent truncation of those equations in this problem. The equations are solved both analytically and numerically, and the dynamic

M. Eidemuller, H. G. Dosch, M. Jamin

The gauge invariant two-point correlator for the gluon field strength tensor in analysed by means of the QCD sum rule method. To this end, we make use of a relation of this correlator to a two-point function for a quark-gluon hybrid in the limit of the quark mass going to infinity. From the sum rules a relation between the gluon correlation length and the gl

Kari Enqvist, John McDonald

In the MSSM, cosmological scalar field condensates formed along flat directions of the scalar potential (Affleck-Dine condensates) are typically unstable with respect to formation of Q-balls, a type of non-topological soliton. We consider the dynamical evolution of the Affleck-Dine condensate in the MSSM. We discuss the creation and linear growth, in F- and

Andreas Vogt

Previous studies of the kinematic coverage for measuring the photon structure function F_2^gamma at a future 500 GeV e^+e^- linear collider are updated using current estimates of luminosities and important detector parameters. The perturbative expansion for the evolution of F_2^gamma is briefly recalled in view of a recent claim that all existing next-to-lea

G. W. Carter, D. Diakonov

We consider the finite density, zero-temperature behaviour of quark matter in the instanton picture. Since the instanton-induced interactions are attractive in both $\bar{q}q$ and $qq$ channels, a competition ensues between phases of matter with condensation in either or both. It results in chiral symmetry restoration due to the onset of diquark condensation

Bo-Qiang Ma

The generalized Crewther relation relates the cross section ratio $R=σ(e^+e^- \to {\rm hadrons})/σ(e^+e^- \to μ^+ μ^-)$ in $e^+e^-$ annihilation with the Bjorken sum rule or the Gross-Llewellyn Smith sum rule in deep inelastic scattering and provides a fundamental connection for observables in Quantum Chromodynamics (QCD) without scale or scheme ambiguities.

Stephen D. H. Hsu, Myckola Schwetz

We investigate the effect of long range magnetic interactions on the renormalization group (RG) evolution of local Cooper pairing interactions near the Fermi surface in high density QCD. We use an explicit cut-off on momentum modes, with special emphasis on screening effects such as Landau damping, to derive the RG equations in a gauge invariant, weak coupli

Olaf Kaczmarek, Frithjof Karsch, Edwin Laermann, Martin Lutgemeier

Heavy quark potentials are investigated at high temperatures. The temperature range covered by the analysis extends from $T$ values just below the deconfinement temperature up to about $4 T_c$ in the deconfined phase. We simulated the pure gauge sector of QCD on lattices with temporal extents of 4, 6 and 8 with spatial volumes of $32^3$. On the smallest latt

Michael L. Kelly

The experimental problem of converting a measured binomial quantity, the fraction of events in a sample that pass a cut, into a physical binomial quantity, the fraction of events originating from a signal source, is described as a system of linear equations. This linear system illustrates several familiar aspects of experimental data analysis. Bayesian proba

S. Ahmed, CLEO Collaboration

We present preliminary results on $b \to s γ$ from the CLEO experiment. An updated result on the branching fraction is reported at $\cal{B}$$(b \to s γ) = (3.15 \pm 0.35 \pm 0.32 \pm 0.26)\times 10^{-4}$, where the first uncertainty is statistical, the second is systematic, and the third for model dependence. We also describe a new analysis performed to sear

A. J. Berlinsky, D. A. Bonn, R. Harris, C. Kallin

The self-consistent t-matrix approximation for impurity scattering in unconventional superconductors is used to interpret recent measurements of the temperature and frequency dependence of the microwave conductivity of YBCO crystals below 20K. In this theory, the conductivity is expressed in terms of a fequency dependent single particle self-energy, determin

A. J. Williamson, Alex Zunger

Excitonic spectra are calculated for free-standing, surface passivated InAs quantum dots using atomic pseudopotentials for the single-particle states and screened Coulomb interactions for the two-body terms. We present an analysis of the single particle states involved in each excitation in terms of their angular momenta and Bloch-wave parentage. We find tha

K. A. Snyder, T. R. Kirkpatrick

A one-dimensional system of masses with nearest-neighbor interactions and periodic boundary conditions is used to study mode decay and ergodicity in nonlinear, disordered systems. The system is given an initial periodic displacement, and the total system energy within a specific frequency channel is measured as a function of time. Results indicate that the r

M. P. Raphael, M. E. Reeves, E. F. Skelton, C. Kendziora

One of the important problems of high-temperature superconductivity is to understand and ultimately to control fluxoid motion. We present the results of a new technique for measuring the pressure dependence of the transition to superconductivity in a diamond anvil cell. By measuring the third harmonic of the {\it ac} susceptibility, we determine the onset of

A. Hanke, M. Krech, F. Schlesener, S. Dietrich

Symmetry breaking surface fields give rise to nontrivial and long-ranged order parameter profiles for critical systems such as fluids, alloys or magnets confined to wedges. We discuss the properties of the corresponding universal scaling functions of the order parameter profile and the two-point correlation function and determine the critical exponents eta_p

S. Sanvito, Y. -K. Kwon, D. Tománek, C. J. Lambert

Using a scattering technique based on a parametrized linear combination of atomic orbitals Hamiltonian, we calculate the ballistic quantum conductance of multi-wall carbon nanotubes. We find that inter-wall interactions not only block some of the quantum conductance channels, but also redistribute the current non-uniformly over the individual tubes across th

V. Kataev, A. Validov, M. Huecker, H. Berg

Measurements of the static magnetization, susceptibility and ESR of Gd spin probes have been performed to study the properties of antiferromagnetically ordered La_{2-x-y}Eu_ySr_xCuO_4 (x less or equal 0.02) with the low temperature tetragonal structure. According to the static magnetic measurements the CuO_2 planes are magnetically decoupled in this structur

P. R. A. Campos, N. G. F. de Medeiros, R. N. Onody

Recently we reported some interesting features of the Wolff's algorithm behavior when applied to the site-bond-correlated Ising model.Our main results were that a stronger correlation diminishes the autocorrelation time but it does not change or affectthe critical dynamic exponent.In this paper, we analyse the Wolff's cluster structure and how it var

D. Hinzke, U. Nowak

With decreasing particle size, different mechanisms dominate the thermally activated magnetization reversal in ferromagnetic particles. We investigate some of these mechanisms for the case of elongated, single-domain nanoparticles which we describe by a classical Heisenberg spin chain driven by an external magnetic field. For sufficiently small system size t

R. A. Zara, R. N. Onody

We study the optimized version of the multiple invasion percolation model. Some topological aspects as the behavior of the acceptance profile, coordination number and vertex type abundance were investigated and compared to those of the ordinary invasion. Our results indicate that the clusters show a very high degree of connectivity, spoiling the usual nodes-

R. N. Onody, N. G. F. de Medeiros

We introduce an age-structured asexual population model containing all the relevant features of evolutionary ageing theories. Beneficial as well as deleterious mutations, heredity and arbitrary fecundity are present and managed by natural selection. An exact solution without ageing is found. We show that fertility is associated with generalized forms of the

Luca Salasnich

We discuss the mean-field approximation for a trapped weakly-interacting Bose-Einstein condensate (BEC) and its connection with the exact many-body problem by deriving the Gross-Pitaevskii action of the condensate. The mechanics of the BEC in a harmonic potential is studied by using a variational approach with time-dependent Gaussian trial wave-functions. In

L. Salasnich, A. Parola, L. Reatto

We study the Bose-Einstein condensate in the MIT double-well trap. We calculate the ground state density profile of $^{23}$Na atoms and the Bogoliubov spectrum of the elementary excitations as function of the strength of the double-well barrier. In particular, we analyze the behavior of quantum-mechanical collective excitations. Finally, we discuss the obser

J. Zeman, G. Martinez, P. H. M. van Loosdrecht, G. Dhalenne

The H-T phase diagram of CuGeO$_3$ has been determined, for different values of the hydrostatic pressure, utilizing optical absorption spectroscopy on the Cu$^{2+}$ d-d transitions. It is shown that the intensity of the related zero phonon line transition is very sensitive to the local environment of Cu$^{2+}$, allowing for precise determination of all phase

Yuuki Watanabe, Seiji Miyashita

In order to study conditions for the appearance of ferromagnetism in a wide filling region, we investigate numerically three types of one-dimensional Lieb-ferrimagnetic Hubbard models: a periodic diamond (PD) chain, a periodic alternately-attached leg (PAAL) chain and an open diamond (OD) chain. All of these models have a flat band (or equivalently, degenera

Yuli V. Nazarov

We present here a novel approach to evaluation of the weak localization correction (WLC) to transport properties of a mesoscopic conductor. It is based on an extension of Keldysh technique and allows one to evaluate the full counting statistics of the current in the conductor. In our opinion, it provides a fresh look on the theory of weak localization.

F. Restagno, H. Gayvallet, L. Bocquet, E. Charlaix

We present a study of humidity effects on the maximum stability angle in granular media. We show that a granular medium of small glass beads exhibits aging properties : the first avalanche angle increases logarithmically with the resting time of the pile. This aging behavior is found to depend on the relative humidity of the surrounding atmosphere. A short i

F. Restagno, L. Bocquet, T. Biben, E. Charlaix

This paper is devoted to the thermally activated dynamics of the capillary condensation. We present a simple model which enables us to identify the critical nucleus involved in the transition mechanism. This simple model is then applied to calculate the nucleation barrier from which we can obtain informations on the nucleation time. We present a simple estim

B. Ludoph, J. M. van Ruitenbeek

Recently it has been observed that the conductance fluctuations of atomic size gold contacts are suppressed when the conductance is equal to an integer multiple of the conductance quantum. The fact that these contacts tend to consist exclusively of fully open or closed modes has been argued to be the origin for this suppression. Here, the experiments have be

P. Markos

We present numerical results for the statistics of $z$'s ($z$'s are defined as logarithm of eigenvalues of the transfermatrix $T^†T$) at the critical points of Anderson transition in 3D and 4D. The change of the density of $z$ due to the crossover from the metallic to the localized regime is described. Linear behavior $ρ(z)= z$ at the critical point

Ben Yu-Kuang Hu

I investigate the possibility of using Coulomb drag to detect a precursor of the predicted (but as yet not definitively observed) superfluid transition in electron-hole coupled quantum wells. The drag transresisitivity $ρ_{21}$ is shown to be significantly enhanced above the transition temperature $T_c$ and to diverge logarithmically as $T\to T_c^+$, due to

Michael W. Regan, Kartik Sheth, Stuart N. Vogel

To quantify the effect that bar driven mass inflow can have on the evolution of a galaxy requires an understanding of the dynamics of the inflowing gas. In this paper we study the kinematics of the dense molecular gas in a set of seven barred spiral galaxies to determine which dynamical effects dominate. The kinematics are derived from observations of the CO

R. D. Preece, M. S. Briggs, R. S. Mallozzi, G. N. Pendleton

This is the first in a series of gamma-ray burst spectroscopy catalogs from the Burst And Transient Source Experiment (BATSE) on the Compton Gamma Ray Observatory, each covering a different aspect of burst phenomenology. In this paper, we present time-sequences of spectral fit parameters for 156 bursts selected for either their high peak flux or fluence. All

René A. Méndez, Imants Platais, Terrence M. Girard, Vera Kozhurina-Platais

Predictions from a Galactic Structure and Kinematic model are compared to the absolute proper-motions of about 30,000 randomly selected stars with $9 < B_{\rm J} \le 19$ derived from the Southern Proper-Motion Program (SPM) toward the South Galactic Pole. The absolute nature of the SPM proper-motions allow us to measure not only the relative motion of the Su

M. Landgraf, W. J. Baggaley, E. Grün, H. Krüger

The in-situ detection of interstellar dust grains in the Solar System by the dust instruments on-board the Ulysses and Galileo spacecraft as well as the recent measurements of hyperbolic radar meteors give information on the properties of the interstellar solid particle population in the solar vicinity. Especially the distribution of grain masses is indicati

Evonne Marietta, Adam Burrows, Bruce Fryxell

One method of discriminating between the many Type Ia progenitor scenarios is by searching for contaminating hydrogen and helium stripped from the companion star. We present several high-resolution 2-D numerical simulations of the impact of a Type Ia supernova explosion with hydrogen-rich main sequence, subgiant, and red giant companions. The binary paramete

Julio F. Navarro, Matthias Steinmetz

We compare the central mass concentration of Cold Dark Matter halos found in cosmological N-body simulations with constraints derived from the Milky Way disk dynamics and from the Tully-Fisher relation. For currently favored values of the cosmological parameters ($Ω_0 \sim 0.3$; $Λ_0=1-Ω_0 \sim 0.7$; $h \sim 0.7$; COBE- and cluster abundance-normalized $σ_8$

James S. Graber

A red hole is &#34;just like a black hole&#34; except it lacks an event horizon and a singularity. As a result, a red hole emits much more energy than a black hole during a collapse or accretion event. We consider how a red hole solution can solve the &#34;energy crisis&#34; and power extremely energetic gamma ray bursts and hypernovae.

Maxim Lyutikov

We show that intensity dependent depolarization of single pulses (e.g., Xiluoris et al. 1994) may be due to the nonlinear decay of the &#34;upper&#34; ordinary mode into an unpolarized extraordinary mode and a backward propagating wave. The decay occurs in the innermost parts of the pulsar magnetosphere for obliquely propagating O waves.

Andrew W. Blain, Ian Smail, Rob Ivison, Jean-Paul Kneib

The first generation of submillimeter(submm)-wave surveys are being carried out using the 450/850-micron SCUBA camera at the JCMT on Mauna Kea. These surveys are potentially sensitive to galaxies at very high redshift, and the galaxies that have been detected so far appear to contribute the greater fraction of the mm/submm-wave background radiation intensity

F. Combes

Interactions between galaxies have spectacular effects on gas dynamics, and small galaxy groups are a privileged place to investigate them. In particular, they could test the existence of cold H2 gas as dark matter in the outer parts of galaxies. HI observations have revealed that galaxies in small groups are deficient in atomic gas, like in richer galaxy cl

N. Magnussen

Currently three ground-based Air Cherenkov detectors with energy thresholds below 50 GeV are being commissioned (CELESTE and STACEE) or under construction (MAGIC Telescope). Based on the expected performance of the MAGIC Telescope and with an emphasis on those physics questions which are unique to the energy domain below 50 GeV an overview of the scientific

F. Herwig, T. Bloecker, N. Langer, T. Driebe

We present an evolutionary sequence of a low mass star from the Asymptotic Giant Branch (AGB) through its post-AGB stage, during which its surface chemical composition changes from hydrogen-rich to strongly hydrogen-deficient as consequence of a very late thermal pulse, following the so-called born-again scenario. The internal structure and abundance changes

Matt J. Jarvis, Steve Rawlings, Chris J. Willott, Katherine M. Blundell

We use three samples (3CRR, 6CE and 6C*) to investigate the radio luminosity function (RLF) for the `most powerful&#39; low-frequency selected radio sources. We find that the data are well fitted by a model with a constant co-moving space density at high redshift as well as by one with a declining co-moving space density above some particular redshift. This

Walter Dehnen

Most late-type stars in the solar neighborhood have velocities similar to the local standard of rest (LSR), but there is a clearly separated secondary component corresponding to a slower rotation and a mean outward motion. Detailed simulations of the response of a stellar disk to a central bar show that such a bi-modality is expected from outer-Lindblad reso

J. H. Fan, R. G. Lin

In this paper, the historical infrared (JHK) data compiled from the published literature are presented in electronic form for 40 radio selected BL Lacertae objects (RBLs) for the first time. Largest variations are found and compared with the largest optical variation. Relations between color index and magnitude and between color-color indices are discussed i

Patrick Hall, Marcin Sawicki, C. J. Pritchet, F. D. A. Hartwick

We present new data on several z=1.54 radio-loud quasar fields from a sample of 31 at z=1-2 in which we have previously identified an excess population of predominantly red galaxies. Narrow-band H-alpha observations detect five candidate galaxies at the quasar redshifts in three fields totaling 10.156 arcmin^2, a surface density 30 times higher than in previ

Andrei Gruzinov

A Kerr black hole can flare quasi-periodically, if it is magnetically connected to the accretion disk. The flares extract the rotational energy of the hole. The flaring occurs because the hole twists the magnetic field lines beyond the threshold of the screw instability.

Donu Arapura, Pramathanath Sastry

Let SU_X(n,L) be the moduli space of rank n semistable vector bundles with fixed determinant L on a smooth projective genus g>1 curve X. Let SU_X^s(n,L) denote the open subset parameterizing stable bundles. We show that for small i, the mixed Hodge structure on H^i(SU_X^s(n, L), Q) is independent of the degree of L, and hence pure of weight i. Moreover any s

G. Aldazabal, A. M. Uranga

We derive the rules to construct type IIB compact orientifolds in six and four dimensions including D-branes and anti-D-branes. Even though the models are non-supersymmetric due to the presence of the anti-D-branes, we show that it is easy to construct large classes of models free of tachyons. Brane-antibrane annihilation can be prevented for instance by con

Masaru Shibata

We present our first successful numerical results of 3D general relativistic simulations in which the Einstein equation as well as the hydrodynamic equations are fully solved. This paper is especially devoted to simulations of test problems such as spherical dust collapse, stability test of perturbed spherical stars, and preservation of (approximate) equilib

D. Augier, J. Riera, D. Poilblanc

The introduction of modified bond-defects in spin-Peierls systems is investigated in a model of antiferromagnetic Heisenberg spin chains coupled to adiabatic phonons. Generically, new low-energy magnetic or non-magnetic excitations appear below the bulk spin gap energy. When two adjacent bonds are modified, these excitations can be interpreted in terms of bo

Donal O&#39;Driscoll

We consider the construction of a general tree level amplitude for the interactions between dynamical D-branes where the configurations have non-zero odd spin structure. Using Riemann Theta Identities we map the conditions for the preservation of some supersymmetry to a set of integer matrices satisfying a simple but non-trivial equation. We also show how th

Eanna E. Flanagan, Donald Marolf, Robert M. Wald

Bousso has conjectured that in any spacetime satisfying Einstein&#39;s equation and satisfying the dominant energy condition, the &#34;entropy flux&#34; S through any null hypersurface L generated by geodesics with non-positive expansion starting from some spacelike 2 surface of area A must satisfy S<=A/4. This conjecture reformulates earlier conjectured ent

Erich J. Mueller, Gordon Baym

We study the mechanical stability of the weakly interacting Bose gas with attractive interactions, and construct a unified picture of the collapse valid from the low temperature condensed region to the high temperature classical regime. As we show, the non-condensed particles play a crucial role in determining the region of stability. We extend our results t

M. Spada, A. Panaitescu, P. Meszaros

In a recent paper we have calculated the power density spectrum of Gamma-Ray Bursts arising from multiple shocks in a relativistic wind. The wind optical thickness is one of the factors to which the power spectrum is most sensitive, therefore we have further developed our model by taking into account the photon down-scattering on the cold electrons in the wi

David A. Brown, Fuqiang Wang, Pawel Danielewicz

The recent NA49 measurement of two-proton correlation function shows an interesting and unexpected structure at large relative momentum. Applying source imaging techniques to the measurement, we find an unusually steep drop-off in the two-proton source function. We show that the steep drop-off is due to the structure in the correlation and the drop-off canno

Alexander K. Hartmann

In cond-mat/9907125 the low-temperature behavior of a model for RNA secondary structure was studied. It is claimed that the model exhibits a breaking of the replica symmetry, since the width of the distribution P(q) of overlaps may converge to a finite value at T=0. The authors used an exact enumeration method to obtain all ground states for a given RNA sequ

Luis Ibanez, Fernando Quevedo

We consider the most general generation-independent U(1) gauge symmetry consistent with the presence of Yukawa couplings for all quarks and leptons in the SUSY version of the Standard Model. This U(1) has generically mixed anomalies with SM groups, which cannot be cancelled by the Green-Schwarz mechanism of heterotic D=4 strings. We argue that these anomalie

E. Kanzieper

Recent developments [Kamenev and Mezard, cond-mat/9901110, cond-mat/9903001; Yurkevich and Lerner, cond-mat/9903025; Zirnbauer, cond-mat/9903338] have revived a discussion about applicability of the replica approach to description of spectral fluctuations in the context of random matrix theory and beyond. The present paper, concentrating on invariant non-Gau

John McDonald

A large neutrino asymmetry is an interesting possibility for cosmology, which can have significant observable consequences for nucleosynthesis and the cosmic microwave background. However, although it is a possibility, there is no obvious reason to expect the neutrino asymmetry to be observably large. Here we note that if the baryon asymmetry originates via

Damien J. Holden, David Wands

We present self-similar cosmological solutions for a barotropic fluid plus scalar field with Brans-Dicke-type coupling to the spacetime curvature and an arbitrary power-law potential energy. We identify all the fixed points in the autonomous phase-plane, including a scaling solution where the fluid density scales with the scalar field&#39;s kinetic and poten

Rob Clifton, Adrian Kent

No physical measurement can be performed with infinite precision. This leaves a loophole in the standard no-go arguments against non-contextual hidden variables. All such arguments rely on choosing special sets of quantum-mechanical observables with measurement outcomes that cannot be simulated non-contextually. As a consequence, these arguments do not exclu

Wei Chen, Kazuo Hida, Bryan C. Sanctuary

One dimensional S=1 antiferromagnetic Heisenberg chains with bond alternation and uniaxial single-ion-type anisotropy are studied by numerical exact diagonalization of finite size systems. We calculate the ground state phase diagram using the twisted boundary condition method for $D\geq 0$. The ground states of this model contain the Haldane state, large-D s

V. Gogohia

The validity of the ladder approximation (LA) in QCD and QED in the context of the corresponding Schwinger-Dyson (SD) equations and Slavnov-Taylor (ST) and Ward-Takahashi (WT) identities is investigated. In contrast to QED, in QCD bacause of color degrees of freedom the summation of the ladder diagrams within the Bethe-Salpeter (BS) integral equation for the

V. Gogohia, H. Toki

Using the trace anomaly relation, low-energy theorem and Witten-Veneziano formula, we have developed an analytical formalism which allows one to calculate the gluon condensate, the topological susceptibility and the mass of the $η&#39;$ meson in the chiral limit as functions of the non-perturbative vacuum energy density. It is used for numerical evaluation o

Markus Buttiker

We evaluate the RC-time of edge states capacitively coupled to a gate located away from a QPC which allows for partial transmission of an edge channel. At long times or low frequencies the RC-time governs the relaxation of charge and current and governs the fluctuations of the equilibrium electrostatic potential. The RC-time in mesoscopic structures is deter

Shin&#39;ichi Nojiri, Sergei D. Odintsov

We study the role of higher derivative terms (Riemann curvature squared ones) in thermodynamics of SCFTs via AdS/CFT correspondence. Using IIB string effective action (d5 AdS gravity) with such HD terms deduced from heterotic string via duality we calculate strong coupling limit of ${\cal N}=2$ SCFT free energy with the account of next to leading term in lar

Carlo Angelantonj

We study the effect of a non-vanishing flux for the NS-NS antisymmetric tensor in open-string orbifolds. As in toroidal models, the total dimension of the Chan-Paton gauge group is reduced proportionally to the rank of $B_{ab}$, both on D9 and on D5-branes, while the Moebius amplitude involves some signs that, in the $Z_2$ case, allow one to connect continuo

Fernando Cornet, Monica Relano, Javier Rico

We study the bounds that can be obtained on four-fermion contact terms from the experimental data for (e+ p -> \bar{nu} X) obtained at HERA and (p \bar{p} -> e ν), measured at TEVATRON. We compare these bounds with the ones available in the literature. Finally, we apply these results to study the compactification radius in theories with large extra dimension

Wen-Xiu Ma, Ruguang Zhou

A coupled AKNS-Kaup-Newell hierarchy of systems of soliton equations is proposed in terms of hereditary symmetry operators resulted from Hamiltonian pairs. Zero curvature representations and tri-Hamiltonian structures are established for all coupled AKNS-Kaup-Newell systems in the hierarchy. Therefore all systems have infinitely many commuting symmetries and

Tommaso Calarco, Marcello Cini, Roberto Onofrio

The possibility of observing violations of temporal Bell inequalities, originally proposed by Leggett as a mean of testing the quantum mechanical delocalization of suitably chosen macroscopic bodies, is discussed by taking into account the effect of the measurement process. A general criterion quantifying this possibility is defined and shown not to be fulfi

Stephen M. Barnett, Anthony Chefles

This paper has been withdrawn by the authors.

C. Kuhrts, M. Beyer, G. Roepke

We investigate deuteron formation in nuclear matter at finite temperatures within a systematic quantum statistical approach. We consider formation through three-body collisions relevant already at rather moderate densities because of the strong correlations. The three-body in-medium reaction rates driven by the break-up cross section are calculated using exa

I. Passchier, L. D. van Buuren, D. Szczerba, R. Alarcon

We report on the first measurement of spin-correlation parameters in quasifree electron scattering from vector-polarized deuterium. Polarized electrons were injected into an electron storage ring at a beam energy of 720 MeV. A Siberian snake was employed to preserve longitudinal polarization at the interaction point. Vector-polarized deuterium was produced b

Donu Arapura

This is primarily an expository piece and the first sentence of the introduction pretty much sums it up: This article is aimed at people who already know what mixed Hodge structures are and what they are good for, but who are not sure how to construct them.

M. Lubke

A flat complex vector bundle (E,D) on a compact Riemannian manifold (X,g) is stable (resp. polystable) in the sense of Corlette [C] if it has no D-invariant subbundle (resp. if it is the D-invariant direct sum of stable subbundles). It has been shown in [C] that the polystability of (E,D) in this sense is equivalent to the existence of a so-called harmonic m

Akira Higuchi, Hiroyuki Miyoshi, Toru Tsujishita

We introduce higher dimensional hypergraphs, which is a generalization of Baez-Dolans&#39;s opetopic sets and Hermida-Makkai-Power&#39;s multigraphs. This is based on a simple combinatorial structure called shells and the formal composites of pasting diagrams based on the closure of open shells. We give two types of graphical representation of higher dimensi