September 2000 arXiv papers — page 19

Hyunji Cho, Moataz Emam, David Kastor, Jennie Traschen

We show that a class of spacetimes introduced by Fayyazuddin and Smith to describe intersecting M5-branes admit a generalized Kahler calibration. Equipped with this understanding, we are able to construct spacetimes corresponding to further classes of calibrated $p$-brane world-volume solitons. We note that these classes of spacetimes also describe the field

Gary Gibbons, Kentaro Hori, Piljin Yi

We consider Sen's effective action for unstable D-branes, and study its classical dynamics exactly. In the true vacuum, the Hamiltonian dynamics remains well-defined despite a vanishing action, and is that of massive relativistic string fluid of freely moving electric flux lines. The energy(tension) density equals the flux density in the local co-moving

H. W. Braden, A. Marshakov

We consider the singular phases of the smooth finite-gap integrable systems arising in the context of Seiberg-Witten theory. These degenerate limits correspond to the weak and strong coupling regimes of SUSY gauge theories. The spectral curves in such limits acquire simpler forms: in most cases they become rational, and the corresponding expressions for coup

S. Nojiri, S. D. Odintsov, K. E. Osetrin

d5 dilatonic gravity action with surface counterterms motivated by AdS/CFT correspondence and with contributions of brane quantum CFTs is considered around AdS-like bulk. The effective equations of motion are constructed. They admit two (outer and inner) or multi-brane solutions where brane CFTs may be different. The role of quantum brane CFT is in inducing

Mirna Džamonja, Saharon Shelah

This paper investigates a connection between the ordering triangleleft^ast among theories in model theory and the (N)SOP_n hierarchy of Shelah. It introduces two properties which are natural extensions of this hierarchy, called SOP_2 and SOP_1, and gives a strong connection between SOP_1 and the maximality in Keisler ordering. Together with the known results

Ilhan Icen

This is an introduction to the notion of local subgroupoid introduced by the author and R. Brown. It can also serve as an introduction to an application of sheaf theory, and so could be useful to beginners in that theory. The main results are the construction of the holonomy groupoid and the notion of s-sheaf for certain local subgroupoids s.

Binoy Krishna Patra, Dinesh Kumar Srivastava

We evaluate the suppression of $J/ψ$ production in an equilibrating quark gluon plasma for two competing mechanisms: Debye screening of colour interaction and dissociation due to energetic gluons. Results are obtained for $S+S$ and $Au+Au$ collisions at RHIC and LHC energies. At RHIC energies the gluonic dissociation of the charmonium is found to be equally

Eva Silverstein

We study the massive spectrum of fully wrapped branes in warped M-theory compactifications, including regimes where these states are parametrically lighter than the Planck scale or string scale. We show that many such states behave classically as extended objects in the noncompact directions in the sense that their mass grows with their size as measured alon

L. Feher, R. Rimanyi

In this paper we propose a systematic study of Thom polynomials for group actions defined by M. Kazarian. On one hand we show that Thom polynomials are first obstructions for the existence of a section and are connected to several problems of topology, global geometry and enumerative algebraic geometry. On the other hand we describe a way to calculate Thom p

K. O. E. Henriksson, T. A. Lahde, C. J. Nyfalt, D. O. Riska

The pionic decay rates of the excited $L=0,1$ $D$ mesons are calculated with a Hamiltonian model within the framework of the covariant Blankenbecler-Sugar {equation.} The interaction between the light quark and charm antiquark is described by a linear scalar confining and a screened one-gluon exchange interaction. The decay widths of the $D^*$ mesons obtain

N. Cretton, T. Naab, H. -W. Rix, A. Burkert

We test the formation of low-luminosity elliptical galaxies through collisionless mergers of unequal-mass disk galaxies. The kinematic properties of a small survey of simulated merger end-products with initial disk mass ratios of 3:1 is compared to a sample of seven low-luminosity galaxies observed by Rix et al. that were chosen photometrically to be "el

C. van de Bruck, M. Dorca, C. J. A. P. Martins, M. Parry

We investigate cosmological consequences arising from the interaction between a homogeneous and isotropic brane-universe and the bulk. A Friedmann equation is derived which incorporates both the brane and bulk matter contributions, which are both assumed to be of arbitrary fluid form. In particular, new terms arise which describe the energy flow onto (or awa

Pijush K. Ghosh

We show that the two dimensional Calogero-Marchioro Model (CMM) without the harmonic confinement can naturally be embedded into an extended SU(1,1|2) superconformal Hamiltonian. We study the quantum evolution of the superconformal Hamiltonian in terms of suitable compact operators of the N=2 extended de Sitter superalgebra with central charge and discuss the

A. Goksu, E. O. Iltan, L. Solmaz

We study the decay width and CP-asymmetry of the inclusive process b--> s g g (g denotes gluon) in the three and two Higgs doublet models with complex Yukawa couplings. We analyse the dependencies of the differential decay width and CP-asymmetry to the s- quark energy E_s and CP violating parameter θ. We observe that there exist a considerable enhancement in

Tetsufumi Tanamoto

Coulomb blockade effects in capacitively coupled quantum dots can be utilized for constructing an N-qubit system with antiferromagnetic Ising interactions. Starting from the tunneling Hamiltonian, we theoretically show that the Hamiltonian for a weakly coupled quantum-dot array is reduced to that for nuclear magnetic resonance (NMR) spectroscopy. Quantum ope

Eric A. Galapon

We raise the problem of constructing quantum observables that have classical counterparts without quantization. Specifically we seek to define and motivate a solution to the quantum-classical correspondence problem independent from quantization and discuss the general insufficiency of prescriptive quantization, particularly the Weyl quantization. We demonstr

Christopher Gordon, David Wands, Bruce A. Bassett, Roy Maartens

We study adiabatic (curvature) and entropy (isocurvature) perturbations produced during a period of cosmological inflation that is driven by multiple scalar fields with an arbitrary interaction potential. A local rotation in field space is performed to separate out the adiabatic and entropy modes. The resulting field equations show explicitly how on large sc

J. Richert, P. Wagner

The properties of excited nuclear matter and the quest for a phase transition which is expected to exist in this system are the subject of intensive investigations. High energy nuclear collisions between finite nuclei which lead to matter fragmentation are used to investigate these properties. The present report covers effective work done on the subject over

D. V. Khveshchenko, J. Paaske

The possibility of a second pairing transition $d\to d+is$ ($d+id^\prime$) in planar $d$-wave superconductors which occurs in the absence of external magnetic field, magnetic impurities or boundaries is established in the framework of the non-perturbative phenomenon of dynamical chiral symmetry breaking in the system of $2+1$-dimensional Dirac-like nodal qua

Ted Jacobson, David Mattingly

Short distance structure of spacetime may show up in the form of high freqency dispersion. Although such dispersion is not locally Lorentz invariant, we show in a scalar field model how it can nevertheless be incorporated into a generally covariant metric theory of gravity provided the locally preferred frame is dynamical. We evaluate the resulting energy-mo

Zoltan Haiman, Tom Abel, Piero Madau

At the earliest epochs of structure formation in cold dark matter (CDM) cosmologies, the smallest nonlinear objects are the numerous small halos that condense with virial temperatures below 10,000 K. Such ``minihalos'' are not yet resolved in large-scale three-dimensional cosmological simulations. Here we employ a semi-analytic method, combined with

Yoshihiro Nishiyama

Electron gas in a wire connected to two terminals with potential drop is studied with the Schwinger-Keldysh formalism. Recent studies, where the current is enforced to flow with a Lagrange-multiplier term, demonstrated that the current enhances the one-particle-correlation function. We report that in our model, such enhancement is not guaranteed to occur, bu

C. F. Roos, D. Leibfried, A. Mundt, F. Schmidt-Kaler

Ground state laser cooling of a single trapped ion is achieved using a technique which tailors the absorption profile for the cooling laser by exploiting electromagnetically induced transparency in the Zeeman structure of a dipole transition. This new method is robust, easy to implement and proves particularly useful for cooling several motional degrees of f

Nuno Barros e Sa

A modified definition of quantum mechanical uncertainty D for spin systems, which is invariant under the action of SU(2), is suggested. Its range is shown to be h^2j<D<h^2j(j+1) within any irreducible representation j of SU(2) and its mean value in Hilbert space computed using the Fubini-Study metric is determined to be mean(D)=h^2j(j+1/2). The most used set

H. Rohde, S. T. Gulde, C. F. Roos, P. A. Barton

We have cooled a two-ion-crystal to the ground state of its collective modes of motion. Laser cooling, more specific resolved sideband cooling is performed sympathetically by illuminating only one of the two $^{40}$Ca$^+$ ions in the crystal. The heating rates of the motional modes of the crystal in our linear trap have been measured, and we found them consi

M. Genovese, C. Novero

In this proceeding we describe various proposals of application of an high coefficient Kerr cell to quantum states manipulation, ranging from fast modulation of quantum interference, GHZ states generation, Schroedinger cats creation, translucent eavesdropping, etc.

Ilya Nemenman

We try to establish a unified information theoretic approach to learning and to explore some of its applications. First, we define {\em predictive information} as the mutual information between the past and the future of a time series, discuss its behavior as a function of the length of the series, and explain how other quantities of interest studied previou

Z. Li, N. T. Folwell, K. Ko, R. J. Loewen

The complexity of the Round Damped Detuned Structue (RDDS) for the JLC/NLC main linac is driven by the considerations of rf efficiency and dipole wakefield suppression. As a time and cost saving measure for the JLC/NLC, the dimensions of the 3D RDDS cell are being determined through computer modeling to within fabrication precision so that no tuning may be n

J. B. Kirk, C. R. Bennett, M. Babiker, S. Al-Awfi

A theory of evanescent mode atomic mirrors utilising a metallic sheet on a dielectric substrate is described. The emphasis here is on the role of the metallic sheet and on the evaluation of atomic trajectories using the field- dipole orientation picture. At low intensity, the atomic reflection process is controlled by two separate mechanisms both of which ar

Miguel Alcubierre, Bernard F. Schutz

Moving grids are of interest in the numerical solution of hydrodynamical problems and in numerical relativity. We show that conventional integration methods for the simple wave equation in one and more than one dimension exhibit a number of instabilities on moving grids. We introduce two techniques, which we call causal reconnection and time-symmetric ADI, w

Arindam Mitra

A simple unbreakable cipher system is presented which uses the concept of &#34;pseudo-bits&#34; that has never been used in either classical or quantum cryptography.

Friedrich W. Hehl, Yuri N. Obukhov

The axiomatic structure of the electromagnetic theory is outlined. We will base classical electrodynamics on (1) electric charge conservation, (2) the Lorentz force, (3) magnetic flux conservation, and (4) on the Maxwell-Lorentz spacetime relations. This yields the Maxwell equations. The consequences will be drawn, inter alia, for the interpretation and the

Jianzhong Gu, H. A. Weidenmueller

We implement the Brink-Axel hypothesis for the excitation of the double giant dipole resonance (DGDR): The background states which couple to the one-phonon giant dipole resonance are themselves capable of dipole absorption. These states (and the ones which couple to the two-phonon resonance) are described in terms of the Gaussian Orthogonal Ensemble of rando

Alfred Svarc, Sasa Ceci

A short, and definitely not a complete representation of ηproduction processes on hadrons is given. First of all, the different ways of obtaining the πN \to ηN and πN \to ηN amplitudes are presented. After that, an overview of results obtained using these amplitudes as input for calculating processes like: NN \to ηNN, pd \to η^{3}He, πd \to ηNN and ηd, η^{3}

E850 Collaboration, A. Tang, J. Alster, G. Asryan

Recently, a new technique for measuring short-range NN correlations in nuclei (NN SRCs) was reported by the E850 collaboration, using data from the EVA spectrometer at the AGS at Brookhaven Nat. Lab. In this talk, we will report on a larger set of data from new measurement by the collaboration, utilizing the same technique. This technique is based on a very

E850 Collaboration, A. Leksanov, J. Alster, G. Asryan

We present a new measurement of the energy dependence of nuclear transparency from AGS experiment E850, performed using the EVA solenoidal spectrometer, upgraded since 1995. Using a secondary beam from the AGS accelerator, we simultaneously measured $pp$ elastic scattering from hydrogen and $(p,2p)$ quasi-elastic scattering in carbon at incoming momenta of 5

E850 Collaboration, D. Zhalov, S. Heppelmann, J. Alster

We present an analysis of new data from Experiment E850 at BNL. We have characterized the inclusive cross section near the endpoint for pp exclusive scattering in Hydrogen and in Carbon with incident beam energy of 6 GeV. We select events with a pair of back-to-back hadrons at large transverse momentum. These cross sections are parameterized with a form $\fr

Michael Blank

For a family of $n*n$ left triangular matrices with binary entries we derive asymptotically exact (as $n\to\infty$) representation for the complete eigenvalues-eigenvectors problem. In particular we show that the dependence of all eigenvalues on $n$ is asymptotically linear for large $n$. A similar result is obtained for more general (with specially scaled e

Ph. Feinsilver, J. Kocik, R. Schott

We examine the Schrodinger algebra in the framework of Berezin quantization. First, the Heisenberg-Weyl and sl(2) algebras are studied. Then the Berezin representation of the Schrodinger algebra is computed. In fact, the sl(2) piece of the Schrodinger algebra can be decoupled from the Heisenberg component. This is accomplished using a special realization of

Elliott H. Lieb

Now that the properties of the ground state of quantum-mechanical many-body systems (bosons) at low density, $ρ$, can be examined experimentally it is appropriate to revisit some of the formulas deduced by many authors 4-5 decades ago. One of these is that the leading term in the energy/particle is $4πa ρ$ where $a$ is the scattering length of the 2-body pot

Hajime Tsuji

We prove the finite generation of canonical rings of projective variety of general type defined over complex numbers.

A. Verra

Refereed version to appear on Journal of Algebraic Geometry. Unchanged content. Strongly ameliorated presentation thanks to referee&#39;s action.

J. Cortes, S. Martinez

We investigate local configuration controllability for mechanical control systems within the affine connection formalism. Extending the work by Lewis for the single-input case, we are able to characterize local configuration controllability for systems with $n$ degrees of freedom and $n-1$ input forces.

Laurent Vuillon

In this article, we count the number of return words in some infinite words with complexity 2n+1. We also consider some infinite words given by codings of rotation and interval exchange transformations on k intervals. We prove that the number of return words over a given word w for these infinite words is exactly k.

O. Garcia-Prada, S. Ramanan

We study polystable Higgs bundles twisted by a line bundle over a compact Kähler manifold. These form a Tannakian category when the first and second Chern classes of the bundle are zero. In this paper we identify the corresponding Tannaka group in the case in which the line bundle is of finite order. This group is described in terms of the pro-reductive comp

E. Peyre, Y. Tschinkel

We consider diagonal cubic surfaces defined by an equation of the form ax^3+by^3+cz^3+dt^3 = 0. Numerically, one can find all rational points of height < B for B in the range of up to 100 000, thanks to a program due to D. J. Bernstein. On the other hand, there are precise conjectures concerning the constants in the asymptotics of rational points of bounded

Rüdiger Göbel, Saharon Shelah

Philip Hall raised around 1965 the following question which is stated in the Kourovka Notebook: Is there a non-trivial group which is isomorphic with every proper extension of itself by itself? We will decompose the problem into two parts: We want to find non-commutative splitters, that are groups G not= 1 with Ext(G,G)=1 . The class of splitters fortunately

Jeffrey Shallit, Ming-wei Wang

H. Friedman obtained remarkable results about the longest finite sequence $x$ such that for all $i \not= j$ the word $x[i..2i]$ is not a subsequence of $x[j..2j]$. In this note we consider what happens when ``subsequence&#39;&#39; is replaced by ``subword&#39;&#39;.

Rüdiger Göbel, Saharon Shelah

A group homomorphism eta:A-> H is called a localization of A if every homomorphism phi:A-> H can be `extended uniquely&#39; to a homomorphism Phi:H-> H in the sense that Phi eta = phi. This categorical concepts, obviously not depending on the notion of groups, extends classical localizations as known for rings and modules. Moreover this setting has interesti

Rüdiger Göbel, Agnes T. Paras, Saharon Shelah

In answer to a question of P. Hall, we supply another construction of a group which is isomorphic to each of its non-trivial normal subgroups.

Janusz Szczepanski

Investigations of complexity of sequences lead to important applications such as effective data compression, testing of randomness, discriminating between information sources and many others. In this paper we establish formulas describing the distribution functions of random variables representing the complexity of finite sequences introduced by Lempel and Z

Stefan Kebekus

Classification theory and the study of projective varieties which are covered by rational curves of minimal degrees naturally leads to the study of families of singular rational curves. Since families of arbitrarily singular curves are hard to handle, it has been shown in a previous paper that there exists a partial resolution of singularities which transfor

Nathanial P. Brown

Let T be a quasidiagonal operator on a separable Hilbert space. Then T is the norm limit of operators, each of which generate a finite dimensional C*-algebra, if and only if the C*-algebra generated by T is exact.

Ernst Heintze, Xiaobo Liu, Carlos Olmos

We define and study isoparametric submanifolds of general ambient spaces and of arbitrary codimension. In particular we study their behaviour with respect to Riemannian submersions and their lift into a Hilbert space. These results are used to prove a Chevalley type restriction theorem which relates by restriction eigenfunctions of the Laplacian on a compact

Katherine Brading, Harvey R. Brown

Consideration of the Noether variational problem for any theory whose action is invariant under global and/or local gauge transformations leads to three distinct theorems. These include the familiar Noether theorem, but also two equally important but much less well-known results. We present, in a general form, all the main results relating to the Noether var

Jean-Pierre Derendinger, Roger Sauser

Five-branes lead in four dimensions to massless N=1 supermultiplets if M-theory is compactified on S1/Z2 x (a Calabi-Yau threefold). One of them describes the modulus associated with the position of the five-brane along the circle S1. We derive the effective four-dimensional supergravity of this multiplet and its coupling to bulk moduli and to Yang-Mills and

Valerio Faraoni

Nonminimal coupling of the inflaton field to the Ricci curvature of spacetime is generally unavoidable, and the paradigm of inflation should be generalized by including the corresponding term in the Lagrangian of the inflationary theory. This paper reports on the status of the programme of generalizing inflation. First, the problem of finding the correct val

Takeshi Sato

We discuss the relations of the M-9-brane with other branes via dimensional reductions, mainly focusing on their Wess-Zumino (WZ) actions. It is shown that on three kinds of dimensional reductions, the WZ action of the M-9-brane respectively gives those of the D-8-brane, the ``KK-8A brane&#39;&#39; (which we regard as a kind of D-8-brane) and the ``NS-9A bra

Ethan Honda

This dissertation discusses solutions to the nonlinear Klein-Gordon equation with symmetric and asymmetric double-well potentials, focusing on the collapse and collision of bubbles and critical phenomena found therein. A new method is presented that allows the solution of massive field equations on a (relatively) small static grid. A coordinate transformatio

L. Bourhis, M. Fontannaz, J. Ph. Guillet, M. Werlen

We analyse LEP and PETRA data on single inclusive charged hadron cross-sections to establish new sets of Next-to-Leading order Fragmentation Functions. Data on hadro-production of large-$p_{\bot}$ hadrons are also used to constrain the gluon Fragmentation Function. We carry out a critical comparison with other NLO parametrizations.

E. E. Boos

A review of results on top quark physics expected at the Photon Linear Colliders is presented.

H. Satz

Over the past 15 years, an extensive program of high energy nuclear collisions at BNL and CERN has been devoted to the experimental search for the quark-gluon plasma predicted by QCD. The start of RHIC this year will increase the highest available collision energy by a factor 10. This seems a good time for a critical assessment: what have we learned so far a

B. Guberina, B. Melic, H. Stefancic

We discuss the lifetime pattern of weakly decaying heavy hadrons.

Uma Mahanta

In this paper we express the effect of new physics on gauge boson self energy corrections through non-renormalizable dimension six operators. Using the precision electroweak data we then determine a lower bound on the scale $ł$ associated with the underlying new physics. The lower bound on $ł$ is then used to derive an upper bound on $m_h$ through the trivia

UKQCD Collaboration, A. Hart, M. Teper

We study the topological susceptibility, chi, in two flavour lattice QCD. We find clear evidence for the expected suppression of chi at small quark mass. The estimate of the pion decay constant, f_pi = 105 +/-5 +18/-10 MeV, is consistent with the experimental value of approximately 93 MeV. We compare chi to the large-N_c prediction and find consistency over

David A. Sanders

I briefly review the results of recent searches for flavor-changing neutral current and lepton-flavor and lepton-number violating decays of D+, Ds, and D0 mesons (and their antiparticles) into modes containing muons and electrons. The primary focus is the results from Fermilab charm hadroproduction experiment E791. E791 examined 24 pi,l,l and K,l,l decay mod

Marco Battaglia

Recent analyses of the LEP and Y(4S) data have better outlined the picture of semileptonic B decays. Results on inclusive and exclusive decay branching fractions and on the extraction of the Vub and Vcb elements of the CKM mixing matrix are discussed, together with some of the still open questions and the sources of model systematics.

Stefan Soldner-Rembold

The structure of the photon is probed in photon-photon interactions at LEP and in photon-proton interactions at HERA.

Luis O. Pimentel, Cesar Mora

The Wheeler-DeWitt equation is solved for the Bergmann-Wagoner scalar-tensor gravitational theory in the case of Friedmann-Robertson- Walker cosmological model. We present solutions for several cosmological functions: i) λ(ϕ)=0, ii) λ(ϕ)=3Λ_0ϕand iii) a more complex λ(ϕ), that depends on the choice of the coupling function, considering closed, flat and hyper

Luis O. Pimentel, Cesar Mora

We study the third quantization of a Brans-Dicke toy model, we calculate the number density of the universes created from nothing and found that it has a Planckian form. Also, we calculated the uncertainty relation for this model by means of functional Schr&#34;odinger equation and we found that fluctuations of the third-quantized universe field tends to a f

I. G. Dymnikova, M. L. Fil&#39;chenkov

We consider quantum birth of a hot Universe in the framework of quantum qeometrodynamics in the minisuperspace model. The energy spectrum of the Universe in the pre-de-Sitter domain naturally explains the cosmic microwave background (CMB) anisotropy. The false vacuum where the Universe tunnels from the pre-de-Sitter domain is assumed to be of a Grand Unifica

Philippos Papadopoulos, Jose A. Font

Black holes are superb sources of gravitational wave signals, for example when they are born in stellar collapse. We explore the subtleties that may emerge if mass accretion events increase significantly the mass of the black hole during its gravitational wave emission. We find the familiar damped-oscillatory radiative decay but now both decay rate and frequ

Reginald T. Cahill, Christopher M. Klinger, Kirsty Kitto

The new Process Physics models reality as self-organising relational information and takes account of the limitations of logic, discovered by Godel and extended by Chaitin, by using the concept of self-referential noise. Space and quantum physics are emergent and unified, and described by a Quantum Homotopic Field Theory of fractal topological defects embedd

Anoop Sarkar, Daniel Zeman

We present some novel machine learning techniques for the identification of subcategorization information for verbs in Czech. We compare three different statistical techniques applied to this problem. We show how the learning algorithm can be used to discover previously unknown subcategorization frames from the Czech Prague Dependency Treebank. The algorithm

John Watrous

In this paper we consider a quantum computational variant of nondeterminism based on the notion of a quantum proof, which is a quantum state that plays a role similar to a certificate in an NP-type proof. Specifically, we consider quantum proofs for properties of black-box groups, which are finite groups whose elements are encoded as strings of a given lengt

A. E. Koshelev, I. S. Aranson

We investigate dynamics of Josephson vortex lattice in layered high T$_{c}$ superconductors at high magnetic fields. It is shown that the average electric current depends on the lattice structure and is resonantly enhanced when the Josephson frequency matches the frequency of the plasma mode. We find the stability regions of moving lattice. It is shown that

Vladimir L. Safonov, H. Neal Bertram

Magnetization reversal in a fine ferromagnetic grain is simulated for the case of an instantaneously applied reversal magnetic field. The Hamiltonian of the system contains the exchange interaction, the uniaxial anisotropy, the Zeeman energy and the dipole-dipole interactions. A cubic grain is discretized into 64 cubic subgrains and the coupled gyromagnetic

Sonali Mukherjee, R. E. Cohen, Oguz Gulseren

We have computed the variation of the vacancy formation energy with pressure for Ta. Total energy calculations were performed for 16 and 54 atom supercells using a mixed basis pseudopotential method which uses pseudo-atomic orbitals and low energy plane waves as the basis set, within density functional theory (LDA and GGA). The vacancy formation energy is fo

C. P. Adams, J. W. Lynn, Y. M. Mukovskii, A. A. Arsenov

Neutron scattering has been used to study the nature of the ferromagnetic transition in a single crystal of the perovskite La0.7Ca0.3MnO3. Diffuse scattering from lattice polarons develops as the Curie temperature is approached from below, along with short range polaron correlations that are consistent with stripe formation. Both the scattering due to the po

Philip Phillips

The recent observation by Batlogg and colleagues of superconductivity in an organic field-effect transistor is reviewed.

Christopher L. Henley

What is the zero-temperature ordering pattern of a Heisenberg antiferromagnet with large spin length $S$ (and possibly small dilution), on the kagome lattice, or others built from corner-sharing triangles and tetrahedra? First, I summarize the uses of effective Hamiltonians to resolve the large ground-state degeneracy, leading to long-range order of the usua

Jure Dobnikar, Rudi Podgornik

We investigate the pseudo-Casimir force in a slab of material composed of nematically ordered long polymers. We write the total mesoscopic energy together with the constraint connecting the local density and director fluctuations and evaluate the corresponding fluctuation free energy by standard methods. It leads to a pseudo-Casimir force of a different type

C. D. Batista, J. Bonča, J. E. Gubernatis

Using the constrained-path Monte Carlo method, we studied the magnetic properties of the two-dimensional periodic Anderson model for electron fillings between 1/4 and 1/2. We also derived two effective low energy theories to assist in interpreting the numerical results. For 1/4 filling we found that the system can be a Mott or a charge transfer insulator, de

H. Suderow, S. Vieira

We have fabricated superconducting connecting necks of Pb with a scanning tunneling microscope (STM) and studied their properties under magnetic fields near the transition to the resistive state. A striking phenomenology is found with two well defined conduction regimes as a function of the magnetic field. We discuss the possible origin of this behavior in t

A. K. Geim, S. V. Dubonos, I. V. Grigorieva, K. S. Novoselov

As first pointed out by Bardeen and Ginzburg in the early sixties, the amount of magnetic flux carried by vortices depends on their distance to the sample edge and can be smaller than one flux quantum, f0 = h/2e. In bulk superconductors, this reduction of flux becomes negligible already at submicron distances from the edge but, in thin films, the effect may

Boris Chirikov, Oleg Zhirov

A generalization of the fluctuation law (FL) (&#34;theorem&#34;), formulated in 1993 by Evans, Cohen and Morriss for a nonequilibrium steady state, on the chaotic Hamiltonian systems with equilibrium steady state in recent publication ba Evans, Searles and Mittag (cond-mat/0008421) is briefly discussed. We argue that the physical meaning of this law, as pres

Petra M. Gleiss, Peter F. Stadler, Andreas Wagner, David A. Fell

We characterize the distributions of short cycles in a large metabolic network previously shown to have small world characteristics and a power law degree distribution. Compared with three classes of random networks, including Erdoes-Renyi random graphs and synthetic small world networks of the same connectivity, the metabolic network has a particularly larg

T. Ohata, M. Itou, I. Matsumoto, Y. Sakurai

We report high-resolution Compton profiles (CP&#39;s) of Al along the three principal symmetry directions at a photon energy of 59.38 keV, together with corresponding highly accurate theoretical profiles obtained within the local-density approximation (LDA) based band-theory framework. A good accord between theory and experiment is found with respect to the

Mai Suan Li, Daniel Dominguez

We model d-wave ceramic superconductors with a three-dimensional lattice of randomly distributed $π$ Josephson junctions with finite self-inductance. The linear and nonlinear ac resistivity of the d-wave ceramic superconductors is obtained as function of temperature by solving the corresponding Langevin dynamical equations. We find that the linear ac resisti

Alexander L. Fetter, Anatoly A. Svidzinsky

We briefly discuss energy, normal modes and dynamics of a vortex in a trapped Bose-Einstein condensate. Theoretical results are compared with current experiments.

Yuji Sugita, Akio Kitao, Yuko Okamoto

We have developed a new simulation algorithm for free-energy calculations. The method is a multidimensional extension of the replica-exchange method. While pairs of replicas with different temperatures are exchanged during the simulation in the original replica-exchange method, pairs of replicas with different temperatures and/or different parameters of the

Yuji Sugita, Yuko Okamoto

We propose two efficient algorithms for configurational sampling of systems with rough energy landscape. The first one is a new method for the determination of the multicanonical weight factor. In this method a short replica-exchange simulation is performed and the multicanonical weight factor is obtained by the multiple-histogram reweighting techniques. The

R. Prozorov, R. W. Giannetta, J. Schlueter, A. M. Kini

The temperature dependence of the in-plane, λ_{\parallel}, and interplane, λ_{\perp}, London penetration depth was measured in the metal-free all-organic superconductor β-ET (see title) ($T_c \approx$ 5.2 K). λ_{\parallel} ~T^3 up to 0.5 Tc, a power law previously observed only in materials thought to be p-wave superconductors. λ_{\perp} is larger than the s

I. G. Lang, L. I. Korovin, D. A. Contreras-Solorio, S. T. Pavlov

The light absorption {\cal A} and reflection{\calR} coefficients for a three-level system in a quantum well (QW) in a strong magnetic field {\bf H}, directed perpendicularly to the QW&#39;s plane, have been calculated. The energy levels correspond to the ground state and to magnetopolaron energy levels \hbarω_{1(2)} with the inverse lifetimes γ_{r1(2)} and γ

M. J. Fromerth, F. Melia

Recent work on the gas dynamics in the Galactic Center has improved our understanding of the accretion processes in galactic nuclei, particularly with regard to properties such as the specific angular momentum distribution, density, and temperature of the inflowing plasma. This information can be valuable in trying to determine the origin of the Broad Line R

Craig J. Hogan

Circumstances are described in which symmetry breaking during the formation of our three-dimensional brane within a higher-dimensional space in the early universe excites mesoscopic classical radion or brane-displacement degrees of freedom and produces a detectable stochastic background of gravitational radiation. The spectrum of the background is related to

C. Batalha, D. F. Lopes, N. M. Batalha

We present time series spectrophotometric observations of GQ Lupi, a typical representative of the YY Ori subgroup of T Tauri stars that show conspicuous inverse PCygni profiles. The data set consists of 32 exposures taken over 5 and 8 consecutive nights of May and July 1998, respectively, and covers the spectral range of 3100 Å~ $< λ< 5100 $ Å. The region r

M. I. Monteverde, A. Herrero, D. J. Lennon

We present non-LTE analyses of four M33 early B-supergiant stars and five Galactic counterparts. This is the first time that B supergiants beyond the Magellanic Clouds are analyzed by means of detailed Non-LTE techniques. Stellar temperatures, gravities, microturbulences and Si abundances are derived for all objects using the Si ionization equilibrium and th

Stephen E. Zepf, Michael A. Beasley, Terry J. Bridges, David A. Hanes

We present new radial velocities for 87 globular clusters around the elliptical galaxy NGC 4472, and combine these with our previously published data to create a data set of velocities for 144 globular clusters around NGC 4472. We utilize this data set to analyze the kinematics of the NGC 4472 globular cluster system. The new data confirms our previous disco

Andreas Albrecht

Defect models of cosmic structure formation have faced a number of difficult challenges over recent years. Yet interestingly, new CMB data does not show strong evidence for secondary oscillations in the anisotropy power. Here I review the current standing of the cosmic defect models of structure formation in light of the current data.