April 2000 arXiv papers — page 12

S. C. C. Ng

We study observational constraints on cosmological models with a quintessence arising from moduli fields. The scalar field potential is given by a double exponential potential V=V_0 exp(-A e^{sqrt{2} kappa phi}). After reviewing the properties of the solutions, from a dynamical systems phase space analysis, we consider the constraints on parameter values imp

J. Kluson

In this short note we would like to propose a form for the action of a non-BPS D-brane, which will be manifestly supersymmetric invariant and T-duality covariant. We also explicitly show that tachyon condensation on the world-volume of this brane leads to the Dirac-Born-Infeld action for BPS D(p-1)-brane.

Nobuhisa Fujita, Komajiro Niizeki

One-dimensional quasilattices, namely, the geometrical objects to represent quasicrystals, are classified into mutual local-derivability (MLD) classes. Besides the familiar class, there exist an infinite number of new MLD classes, and different MLD classes are distinguished by the inflation rules of their representatives. It has been found that electronic pr

N. Gisin, A. Go

We present a unified formalism describing EPR test using spin 1/2 particles, photons and kaons. This facilitates the comparison between existing experiments using photons and kaons. It underlines the similarities between birefringence and polarization dependent losses that affects experiments using optical fibers and mixing and decay that are intrinsic to th

John W. Norbury

A discussion of Lagrangian and Hamiltonian dynamics is presented at a level which should be suitable for advanced high school students. This is intended for those who wish to explore a version of mechanics beyond the usual Newtonian treatment in high schools, but yet who do not have advanced mathematical skills.

John W. Norbury, G. Sudhakaran

This article describes the successful revitalization of an undergraduate physics program. The areas of curriculum development, undergraduate research experiences and advising and retention, to name a few, are emphasized in this interconnecting and systematic approach whereby each and every effort combines to get results. The program can be used by other phys

Tom Ostoma, Mike Trushyk

We provide a quantum derivation of Einstein's Weak Equivalence Principle (WEP) of general relativity using a new quantum gravity theory proposed by the authors called Electro-Magnetic Quantum Gravity or EMQG (ref. 1). Newtonian Inertia is a property of matter due to the strictly local electrical force interactions contributed by each of the (electrically

Alexander A. Vlasov

Motion of a charged particle with finite size, described by Sommerfeld model, in static magnetic field has two peculiar features: 1.) there is the effect of tunneling - Sommerfeld particle overcomes the barrier and finds itself in the forbidden, from classical point of view, area; 2.) the untwisting of trajectory in cyclotron for Sommerfeld particle is stron

B. Krippa

The constraints imposed by chiral symmetry on hadron correlation functions in nuclear medium are discussed. It is shown that these constraints imply a certain structure for the in-medium hadron correlators and lead to the cancelation of the order $ρm_π$ term in the in-medium nucleon correlator. We also consider the effect of mixing of the chiral partners cor

Alessandro La Piana, Winfried Leidemann

The longitudinal structure function of the d(e,e'p) exclusive cross section is calculated with the Lorentz integral transform method. In this approach final state interaction is fully taken into account, but without using a final state wave function. Cross sections are obtained via the inversion of the transform. It is shown that the inversion results ar

S. Yu. Sakovich, Takayuki Tsuchida

A new integrable system of two symmetrically coupled derivative nonlinear Schroedinger equations is detected by means of the singularity analysis. A nonlinear transformation is proposed which uncouples the equations of the new system.

W. E. Bies, L. Kaplan, M. R. Haggerty, E. J. Heller

We present a systematic survey of scarring and symmetry effects in the stadium billiard. The localization of individual eigenfunctions in Husimi phase space is studied first, and it is demonstrated that on average there is more localization than can be accounted for on the basis of random-matrix theory, even after removal of bouncing-ball states and visible

Caroline Grant Melles, Pierre Milman

We construct complete Kahler metrics of Saper type on the nonsingular set of a subvariety X of a compact Kahler manifold using (a) a method for replacing a sequence of blow-ups along smooth centers, used to resolve the singularities of X, with a single blow-up along a product of coherent ideals corresponding to the centers and (b) an explicit local formula f

Vitaly Linchenko, Susan Montgomery

In this note we prove a generalization of the Frobenius-Schur theorem for finite groups for the case of semisimple Hopf algebra over an algebraically closed field of characteristic 0. A similar result holds in characteristic $p > 2$ if the Hopf algebra is also cosemisimple. In fact we show a more general version for any finite-dimensional semisimple algebra

Christine Lescop

We refine a Le and Murakami uniqueness theorem for the Kontsevich Integral in order to specify the relationship between the two (possibly equal) main universal link invariants: the Kontsevich Integral and the perturbative expression of the Chern-Simons theory. As a corollary, we prove that the Altschuler and Freidel anomaly (that groups the Bott and Taubes a

Isabel M. C. Salavessa, Giorgio Valli

We define broadly-pluriminimal immersed 2n-submanifold F: M --> N into a Kaehler-Einstein manifold of complex dimension 2n and scalar curvature R. We prove that, if M is compact, n \geq 2, and R < 0, then: (i) Either F has complex or Lagrangian directions; (ii) If n = 2, M is oriented, and F has no complex directions, then it is a Lagrangian submanifold, gen

Yujiro Kawamata

Let $X$ be a complete normal variety, $B$ an effective $\mathbb{R}$-divisor on $X$, and $D$ a Cartier divisor on $X$. Assume that the pair $(X, B)$ is log terminal. We consider the problem whether $H^0(X, D) \ne 0$ and obtain some results in lower dimensions.

Isabel M. C. Salavessa, Giorgio Valli

We consider $F: M \to N$ a minimal oriented compact real 2n-submanifold M, immersed into a Kaehler-Einstein manifold N of complex dimension 2n, and scalar curvature R. We assume that $n \geq 2$ and F has equal Kaehler angles. Our main result is to prove that, if n = 2 and $R \neq 0$, then F is either a complex submanifold or a Lagrangian submanifold. We also

I. Ya. Aref&#39;eva, M. G. Ivanov, W. Mueck, K. S. Viswanathan

A globally consistent treatment of linearized gravity in the Randall-Sundrum background with matter on the brane is formulated. Using a novel gauge, in which the transverse components of the metric are non-vanishing, the brane is kept straight. We analyze the gauge symmetries and identify the physical degrees of freedom of gravity. Our results underline the

M. Cadoni, P. Carta, S. Mignemi

We discuss the possibility of realizing the infinite dimensional symmetries of conformal mechanics as time reparametrizations, generalizing the realization of the SL(2,R) symmetry of the de Alfaro, Fubini, Furlan model in terms of quasi--primary fields. We find that this is possible using an appropriate generalization of the transformation law for the quasi-

C. Van Den Broeck

Withdrawn due to the absence of an important shear term in Eq. (6), which cancels the other term.

R. Martinez, J. -Alexis Rodriguez, M. Vargas

We study the dominant decays of the lightest Higgs boson in models with 2 and 3 Higgs doublets, for the case when its couplings to fermions are absent at tree-level. It is found that the branching ratio for the decay $H\to γγ$ is above the one into fermion pairs, which is evaluated also at the 1-loop level.

Ph. Brax, C. A. Savoy

We study the decoupling of the first two squark and slepton families in order to lower the flavour changing neutral current effects. Models with inverse sfermion mass hierarchy based upon gauged U(1) flavour symmetries provide a natural framework where decoupling can be implemented. Decoupling requires a large gap between the Fermi scale and the supersymmetr

Patrik Eden

I discuss a Monte Carlo algorithm for hadronization in the Lund string fragmentation picture, which conserves energy and momentum exactly as is proposed by the model. An embryo to this Monte Carlo is used to calculate the total decay density of a string. This is found to reach its predicted asymptotic behaviour already at a string energy of about six hadron

V. M. Strakhovenko

The density matrix is obtained for short-wavelength photons passing through a medium. For sufficiently large thicknesses of a target this matrix is expressed by the forward scattering amplitude of a photon. For multi-GeV photons scattering via virtual electron-positron pairs is the most important process. Its amplitude in a crystal is calculated. The results

Alex Krasnitz, Raju Venugopalan

The dynamics of low-x partons in the transverse plane of a high-energy nuclear collision is classical, and therefore admits a fully non--perturbative numerical treatment. We report results of a recent study estimating the initial energy density in the central region of a collision. Preliminary estimates of the number of gluons per unit rapidity, and the init

Jelle P. Boersma

We study the effect of non-vanishing surface terms at spatial infinity on the dynamics of a scalar field in an open FLRW spacetime. Starting from the path-integral formulation of quantum field theory we argue that classical physics is described by field configurations which extremize the action functional in the space of field configurations for which the va

Alan D. Rendall

Fuchsian equations provide a way of constructing large classes of spacetimes whose singularities can be described in detail. In some of the applications of this technique only the analytic case could be handled up to now. This paper develops a method of removing the undesirable hypothesis of analyticity. This is applied to the specific case of the Gowdy spac

Michael Fisher, Clare Dixon, Martin Peim

In this article, we examine how clausal resolution can be applied to a specific, but widely used, non-classical logic, namely discrete linear temporal logic. Thus, we first define a normal form for temporal formulae and show how arbitrary temporal formulae can be translated into the normal form, while preserving satisfiability. We then introduce novel resolu

D. B. Saakian

A quadratic extension of REM has been treated. Discussed here is the origin of relation of REM to strings and other complex physical phenomena. Two basic features of the REM class of complex phenomena were identified: the double thermodynamic reflection (a hierarchy of free energies) including the strong reflection at the upper level (the free energy on the

S. R. Krishnakumar, N. Shanthi, Priya Mahadevan, D. D. Sarma

We investigate the electronic structure of the metallic NiS$_{1-x}$Se$_x$ system using various electron spectroscopic techniques. The band structure results do not describe the details of the spectral features in the experimental spectrum, even for this paramagnetic metallic phase. However, a parameterized many-body multi-band model is found to be successful

Juana Moreno, J. A. Sauls

We discuss possible magnetic structures in UPt$_3$ based on our analysis of elastic neutron-scattering experiments in high magnetic fields at temperatures $T<T_N$. The existing experimental data can be explained by a single-{\bf q} antiferromagnetic structure with three independent domains. For modest in-plane spin-orbit interactions, the Zeeman coupling bet

Alessio Filippetti, Nicola A. Hill

We show that the observed transition from rocksalt to orthorhombic P$_{nma}$ symmetry in CrN can be understood in terms of stress anisotropy. Using local spin density functional theory, we find that the imbalance between stress stored in spin-paired and spin-unpaired Cr nearest neighbors causes the rocksalt structure to be unstable against distortions and ju

Timothy Halpin-Healy, Rachayl Novoseller

Because of a close blood relationship between directed percolation & directed polymers in random media, the latter&#39;s journey to asymptotic scaling can be greatly retarded by an uninformed choice of departure point; i.e., the bare-bond PDF employed in the transfer matrix study. Bisecting a gaussian noise distribution, examining DPRM scaling for left & rig

A. A. Zvyagin, H. Johannesson, M. Granath

This is an addendum to our previous work cond-mat/9705048 (published in Europhysics Letters 41, 213 (1998)), clarifying the construction of the two-particle scattering matrices used for studying the magnetic impurity behavior in a multichannel correlated host.

A. A. Zvyagin, H. Johannesson

We present the exact solution of a one-dimensional model of a spin-gapped correlated electron system with hybridization impurities exhibiting both magnetic and mixed-valence properties. The host supports superconducting fluctuations, with a spin gap. The localized electrons create a band of antiferromagnetic spin excitations inside the gap for concentrations

Michael Stone, Kee-Su Park, Anupam Garg

We use a continuous-time path integral to obtain the semiclassical propagator for minimal-spread spin coherent states. We pay particular attention to the ``extra phase&#39;&#39; discovered by Solari and Kochetov, and show that this correction is related to an anomaly in the fluctuation determinant. We show that, once this extra factor is included, the semicl

Oscar Sotolongo-Costa, Arezky H. Rodriguez, G. J. Rodgers

Experiments in which thick clay plates and glass rods are fractured have revealed different behavior of fragment mass distribution function in the small and large fragment regions. In this paper we explain this behavior using non-extensive Tsallis statistics and show how the crossover between the two regions is caused by the change in the fragments&#39; dime

Christian Knetter, Goetz S. Uhrig

We reconsider the 2d model for CuGeO_3 introduced previously (Phys. Rev. Lett. 79, 163 (1997)). Using a computer aided perturbation method based on flow equations we expand the 1-triplet dispersion up to 10th order. The expansion is provided as a polynom in the model parameters. The latter are fixed by fitting the theoretical result to experimental data obta

Michela Rossi, Romualdo Pastor-Satorras, Alessandro Vespignani

We investigate the critical behavior of systems exhibiting a continuous absorbing phase transition in the presence of a conserved field coupled to the order parameter. The results obtained point out the existence of a new universality class of nonequilibrium phase transitions that characterizes a vast set of systems including conserved threshold transfer pro

Ulrich Bilstein, Vladimir Rittenberg

It is shown that an operator (in general non-local) commutes with the Hamiltonian describing the finite XX quantum chain with certain non-diagonal boundary terms. In the infinite volume limit this operator gives the &#34;topological&#34; charge.

I. Sarria, C. Henriques, C. Fiolhais, J. M. Pitarke

We examine thin films of two simple metals (aluminum and lithium) in the stabilized jellium model, a modification of the regular jellium model in which a constant potential is added inside the metal to stabilize the system for a given background density. We investigate quantum-size effects on the surface energy and the work function. For a given film thickne

H. Rosner, S. -L. Drechsler, K. Koepernik, R. Hayn

Electronic structure calculations are presented for the well-known CuGeO3 and the recently discovered isostructural CuSiO3 compounds. The magnitude of the dispersion in chain direction is considerably smaller for CuSiO3, whereas the main interchain couplings are rather similar in both compounds. Starting from extended one-band tight-binding models fitted to

M. J. Martins, B. Nienhuis

We establish exact results for the one-dimensional spin-orbital model for special values of the four-spin interaction $V$ and dimerization parameter $δ$. The first exact result is at $δ=1/2$ and $V=-2$. Because we find a very small but finite gap in this dimerized chain, this can serve as a very strong test case for numerical and approximate analytical techn

Gabriele Ferrari

We propose a new method to cool gaseous samples of neutral atoms. The gas is confined in a non dissipative optical trap in the presence of an homogeneous magnetic field. The method accumulates atoms in the $m_F=0$ Zeeman sub-level. Cooling occurs via collisions that produce atoms in $m_F\neq 0$ states. Thanks to the second order Zeeman effect kinetic energy

Pietro Gianinetti, Alberto Parola

A novel approach for studying phase transitions in systems with quantum degrees of freedom is discussed. Starting from the microscopic hamiltonian of a quantum model, we first derive a set of exact differential equations for the free energy and the correlation functions describing the effects of fluctuations on the thermodynamics of the system. These equatio

V. T. Dolgopolov, A. Gold

The conductivity of a two-dimensional electron gas in a parallel magnetic field is calculated. We take into account the magnetic field induced spin-splitting, which changes the density of states, the Fermi momentum and the screening behavior of the electron gas. For impurity scattering we predict a positive magnetoresistance for low electron density and a ne

Hiroki Nakano, Yukitoshi Motome, Masatoshi Imada

A minimal model is proposed for the perovskite manganese oxides showing the strongly incoherent charge dynamics with a suppressed Drude weight in the ferromagnetic and metallic phase near the insulator. We investigate a generalized double-exchange model including three elements; the orbital degeneracy of $e_g$ conduction bands, the Coulomb interaction and fl

Enrico Celeghini, Mario Rasetti

A quantitative description of the whole process of condensation of bosons in an harmonic trap is given resorting only to Gibbs and Bose postulates, without assuming equipartition nor continuum statistics. Below Tc discrete spectrum theory predicts for the thermo-dynamical variables a behavior different from the continuum case. In particular a new critical te

Lars Bergstrom, Martin Goliath, Ariel Goobar, Edvard Moertsell

Recently, Holz & Wald have presented a new method for determining gravitational lensing effects on, e.g., supernova luminosity versus redshift measurements in inhomogeneous universes. In this paper, their method is generalized in several ways: First, the matter content is allowed to consist of several different types of fluids, possibly with non-vanishing pr

Maxim Lyutikov, Eric G. Blackman

Poynting flux driven outflows from magnetized rotators are a plausible explanation for gamma-ray burst engines. We suggest a new possibility for how such outflows might transfer energy into radiating particles. We argue that the Poynting flux drives non-linearly unstable large amplitude electromagnetic waves (LAEMW) which ``break&#39;&#39; at radii $r_t \sim

Dana E. Lehr, Robert V. Wagoner, Joern Wilms

We report the development of a new tool to determine the origin of quasi-periodic oscillations (QPOs) in accretion disk systems. The technique uses the source energy spectrum and the energy dependence of the QPO fractional amplitude to restrict the location of the emission region of the modulated photons, which are assumed to originate in the inner accretion

Andrea Dieball, Eva K. Grebel

Binary clusters account for more than 10 % of the cluster population in the Magellanic Clouds. Statistically fewer than 50 % of the found pairs are expected to be chance superpositions. We estimated the cluster encounter rate and suggest that tidal capture is an unlikely formation scenario for the formation of binary clusters. Thus, most true binary clusters

Stephane Rauzy, Martin A. Hendry

We present a new method for fitting peculiar velocity models to complete flux limited magnitude-redshifts catalogues, using the luminosity function of the sources as a distance indicator.The method is characterised by its robustness. In particular, no assumptions are made concerning the spatial distribution of sources and their luminosity function. Moreover,

M. Magliocchetti, S. J. Maddox, J. V. Wall, C. R. Benn

We present spectra for a sample of radio sources from the FIRST survey, and use them to define the form of the redshift distribution of radio sources at mJy levels.We targeted 365 sources and obtained 46 redshifts (13 per cent of the sample). We find that our sample is complete in redshift measurement to R $\sim 18.6$, corresponding to $z\sim 0.2$. Early-typ

Andre Maeder, Georges Meynet

First, we review the main physical effects to be considered in the building of evolutionary models of rotating stars on the Upper Main-Sequence (MS). The internal rotation law evolves as a result of contraction and expansion, meridional circulation, diffusion processes and mass loss. In turn, differential rotation and mixing exert a feedback on circulation a

P. Battinelli, R. Capuzzo-Dolcetta, P. W. Hodge, A. Vicari

We present multiband photometric observations of three spiral galaxies selected in a sample suited for the study of young stellar groupings and their relationship with the parent galaxy and the galactic environment. Star forming regions have been identified using an objective technique based on a multivariate statistical analysis. Maps of young star grouping

R. B. Barreiro, M. P. Hobson, A. N. Lasenby, A. J. Banday

We investigate the Gaussianity of the 4-year COBE-DMR data (in HEALPix pixelisation) using an analysis based on spherical Haar wavelets. We use all the pixels lying outside the Galactic cut and compute the skewness, kurtosis and scale-scale correlation spectra for the wavelet coefficients at each scale. We also take into account the sensitivity of the method

Simon P. Driver, Nicholas Cross

We discuss the optical parameter space (luminosity and surface brightness) over which galaxies are known to exist and report on the results from three recent datasets: the Two-degree Field Galaxy Redshift Survey, the Hubble Deep Field north, and the Local Group. These data are combined to provide a unique and comprehensive insight into the luminosity distrib

Norman Gray, Iain J. Coleman

Inverse Problem techniques offer powerful tools which deal naturally with marginal data and asymmetric or strongly smoothing kernels, in cases where parameter-fitting methods may be used only with some caution. Although they are typically subject to some bias, they can invert data without requiring one to assume a particular model for the source. The Backus-

G. Beekman, M. Somers, T. Naylor, C. Hellier

We present red spectra in the region 7000-8300A of the eclipsing dwarf nova IP Peg, with simultaneous narrow-band photometry centered at 7322A. We show that by placing a second star on the slit we can correct for the telluric absorption bands which have hitherto made the TiO features from the secondary star unusable. We use these TiO features to carry out a

F. K. Sutaria

The detection of a pulsed X-ray counterpart (RX J1824.2-2R52P) of the 3.05 ms pulsar PSR 1821-24, suggests the possibility of a part of the rotational energy loss of this high spindown rate pulsar being in the optical band. Archival HST data for M28 is used here to set upper limits on the optical V-band magnitude of PSR 1821-24. The optical limit extends the

Feryal Ozel, Dimitrios Psaltis, Ramesh Narayan

We investigate the effect of a hybrid electron population, consisting of both thermal and non-thermal particles, on the synchrotron spectrum, image size, and image shape of a hot accretion flow onto a supermassive black hole. We find two universal features in the emitted synchrotron spectrum: (i) a prominent shoulder at low (< 10^11 Hz) frequencies that is w

H. Sudou, Y. Taniguchi

We report on large-scale, regular morphological patterns found in the radio jet of the nearby radio galaxy NGC 6251. Investigating morphological properties of this radio jet from the nucleus to a radial distance of $\sim$ 300 arcsec ($\approx$ 140 kpc) mapped at 1662 MHz and 4885 MHz by Perley, Bridle, & Willis, we find three chains, each of which consists o

E. I. Chiang, P. Goldreich

The boundaries of the Uranian epsilon, alpha, and beta rings can be fitted by Keplerian ellipses. The pair of ellipses that outline a given ring share a common line of apsides. Apse alignment is surprising because the quadrupole moment of Uranus induces differential precession. We propose that rigid precession is maintained by a balance of forces due to ring

Stephen Lawrence, Ben Sugerman, Patrice Bouchet, Arlin Crotts

We present the discovery of several new regions of interaction between the ejecta and equatorial circumstellar ring of SN1987A, an interaction leading to a much expanded development of the supernova remnant. We also trace the development of the first such &#34;hot spot,&#34; discovered in 1997, back to 1995. Later hot spots seem to have emerged by early 1999

E. L. Wright

Stellar fluxes from the 2MASS catalog are used to remove the contribution due to Galactic stars from the intensity measured by DIRBE in four regions in the North and South Galactic polar caps. After subtracting the interplanetary and galactic foregrounds, a consistent residual intensity of 14.8 +/- 4.6 kJy/sr or 20.2 +/- 6.3 nW/m^2/sr at 2.2 microns is found

Dilip Kumar Ghosh, Probir Roy, Sourov Roy

Selectron (smuon) pair-production in a next generation Linear Collider, yielding a fast electron (muon) trigger, a visible heavily ionizing track and/or a resolved soft pion impact parameter and overall $\mET$, is shown to provide a smoking gun signature for Anomaly Mediated Supersymmetry Breaking models with a neutral Wino as the Lightest Supersymmetric Par

Daniel A. Dwyer, Krishna Rajagopal

Many extensions of the standard model predict heavy metastable particles which may be modeled as solitons (skyrmions of the Higgs field), relating their particle number to a winding number. Previous work has shown that the electroweak interactions admit processes in which these solitons decay, violating standard model baryon number. We motivate the hypothesi

H. V. Klapdor-Kleingrothaus, H. Päs, U. Sarkar

We discuss violations of CPT and quantum mechanics due to interactions of neutrinos with space-time quantum foam. Neutrinoless double beta decay and oscillations of neutrinos from astrophysical sources (supernovae, active galactic nuclei) are analysed. It is found that the propagation distance is the crucial quantity entering any bounds on EHNS parameters. T

Ruth Gregory

We show how to extend the usual black string instability of vacuum or charged black p-branes to the anti-de Sitter background. The string fragments in an analogous fashion to the $Λ=0$ case, the main difference being that instead of a periodic array of black holes forming, an accumulation of ``mini&#39;&#39; black holes occurs towards the AdS horizon. In the

T. A. S. Haddad, Angsula Ghosh, S. R. Salinas

We use a mixed-spin model, with aperiodic ferromagnetic exchange interactions and crystalline fields, to investigate the effects of deterministic geometric fluctuations on first-order transitions and tricritical phenomena. The interactions and the crystal field parameters are distributed according to some two-letter substitution rules. From a Migdal-Kadanoff

Hiroki Sayama, Les Kaufman, Yaneer Bar-Yam

Sexual reproduction presents significant challenges to formal treatment of evolutionary processes. A starting point for systematic treatments of ecological and evolutionary phenomena has been provided by the gene centered view of evolution which assigns effective fitness to each allele instead of each organism. The gene centered view can be formalized as a d

H. V. Klapdor-Kleingrothaus, H. Päs, U. Sarkar

We study the experimental constraints on theories, where the equivalence principle is violated by dilaton-exchange contributions to the usual graviton-exchange gravity. We point out that in this case it is not possible to have any CPT violation and hence there is no constraint from the CPT violating measurements in the $K-$system. The most stringent bound is

Jerome Magnin

We discuss, at the mean-field level, the asymptotic shape of the reaction fronts in the general nA+mB->C reaction-diffusion processes with initially separated reactants, thus generalizing to arbitrary reaction-order kinetics the work done by Galfi and Racz for the case n=m=1. Consequences for the formation of Liesegang patterns are discussed.

C. King, M. B. Ruskai

The capacity of a quantum channel for transmission of classical information depends in principle on whether product states or entangled states are used at the input, and whether product or entangled measurements are used at the output. We show that when product measurements are used, the capacity of the channel is achieved with product input states, so that

M. C. Chung, Ingo Peschel

For a two-dimensional system of coupled oscillators, the spectra of reduced density matrices can be obtained analytically. This provides an example where the features of these quantities, which are of central importance in numerical studies using the DMRG method, can be seen.

H. Nikolic

We study the role of acceleration in the twin paradox. From the coordinate transformation that relates an accelerated and an inertial observer we find that, from the point of view of the accelerated observer, the rate of the differential lapses of time depends not only on the relative velocity, but also on the product of the acceleration and the distance bet

Janos Torok, Supriya Krishnamurthy, Janos Kertesz, Stephane Roux

We introduce a model for the slow relaxation of an energy landscape caused by its local interaction with a random walker whose motion is dictated by the landscape itself. By choosing relevant measures of time and potential this self-quenched dynamics can be mapped on to the ``True&#39;&#39; Self-Avoiding Walk model. This correspondence reveals that the avera

O. V. Pavlovsky

A finite-energy solution of Yang-Mills theory with a nonstandard lagrangian is provided. Properties of these solution are studied and also a possible physical interpretation is given.

S. K. Adhikari, M. Casas, A. Puente, A. Rigo

Cooper pairing in two dimensions is analyzed with a set of renormalized equations to determine its binding energy for any fermion number density and all coupling assuming a generic pairwise residual interfermion interaction. \ Also considered are Cooper pairs (CPs) with nonzero center-of-mass momentum (CMM)--usually neglected in BCS theory--and their binding

Thomas Mohaupt

We give an elementary introduction to black holes in supergravity and string theory. The focus is on BPS solutions in four- and higher-dimensional supergravity and string theory. Basic ideas and techniques are explained in detail, including exercises with solutions.

X. Martinez-Hidalgo, E. M. Chudnovsky, A. Aharony

We show that the low-temperature physics of molecular nanomagnets, contrary to the prevailing one-molecule picture, must be determined by the long-range magnetic ordering due to many-body dipolar interactions. The calculations here performed, using Ewald&#39;s summation, suggest a ferromagnetic ground state with a Curie temperature of about 130 mK. The energ

Mei Xiaochun

In the current theory of non-Abelian gauge field, we only claim the invariability of Lagrangian, without claim the invariability of the motion equation. This is inconsistent and irrational. It is proved that a restriction relation between gauge potentials and group parameters must be satisfied in order to ensure the gauge invariability of the motion equation

Jun Kikuchi, Kazuhiro Ishiguchi, Kiyoichiro Motoya, Masayuki Itoh

Magnetic properties of a quasi one-dimensional magnet CuV_2O_6 have been studied by means of susceptibility measurement, NMR and powder neutron diffraction. Cu^{2+} spins (S=1/2) order antiferromagnetically below 22.6 K, and the saturation moment is about 0.70 μ_{B} at 0 K. The magnetic structure determined in the present study indicates that in CuV_2O_6 one

Joseph Katz, Isao Okamoto

Isolated isothermal spheres of N gravitationally interacting points with equal mass are believed to be stable when density contrasts do not exceed 709. That stability limit does, however, not take into consideration fluctuations of temperature near the onset of instability. These are important when N is finite. Here we correlate {\it global mean quadratic te

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

We consider brane-world universe where an arbitrary large $N$ quantum CFT is living on the domain wall. This corresponds to implementing of Randall-Sundrum compactification within the context of AdS/CFT correspondence. Using anomaly induced effective action for domain wall CFT the possibility of self-consistent quantum creation of 4d de Sitter wall Universe

M. Spalinski, T. R. Taylor

We discuss Poincare three-brane solutions in D=5 M-Theory compactifications on Calabi-Yau (CY) threefolds with G-fluxes. We show that the vector moduli freeze at an attractor point. In the case with background flux only, the spacetime geometry contains a zero volume singularity with the three-brane and the CY space shrinking simultaneously to a point. This p

D. Rainwater

We propose a new method for measuring the H -> bb rate at the CERN LHC in a manner which would allow extraction of the b quark Yukawa coupling. Higgs boson production in purely electroweak WHjj events is calculated. The Standard Model signal rate including decays W -> l nu and H -> bb is 11 fb for M_H = 120 GeV. It is possible to suppress the principal backg

Y. S. Kim

The energy-mass content of Einstein&#39;s E = mc^{2} is well known. For a fixed value of mass, E = mc^{2} is an energy-momentum relation which takes the form E = \sqrt{m^{2} + p^{2}}. This relation was formulated in 1905 for point particles. Since then, particles have become more complicated. They have internal space-time structures. Massive particles carry

Jean-Pierre Amiet, Stefan Weigert

A general relation between the Moyal formalisms for a spin and a particle is established. Once the formalism has been set up for a spin, the phase-space description of a particle is obtained from the `contraction&#39; of the group of rotations to the group of translations. This is shown by explicitly contracting a spin Wigner-kernel to the Wigner kernel of a

J. Fiurasek, M. Dakna, T. Opatrny, D. -G. Welsch

We discuss the possibility of sampling exponential moments of the canonical phase from the s-parametrized phase space functions. We show that the sampling kernels exist and are well-behaved for any s>-1, whereas for s=-1 the kernels diverge in the origin. In spite of that we show that the phase space moments can be sampled with any predefined accuracy from t

Taksu Cheon, Pavel Exner, Petr Seba

We discuss a model in which a quantum particle passes through $δ$ potentials arranged in an increasingly sparse way. For infinitely many barriers we derive conditions, expressed in terms ergodic properties of wave function phases, which ensure that the point and absolutely continuous parts are absent leaving a purely singularly continuous spectrum. For a fin

R. Bijker, F. Iachello, A. Leviatan

The algebraic treatment of baryons is extended to strange resonances. Within this framework we study a collective string-like model in which the radial excitations are interpreted as rotations and vibrations of the strings. We derive a mass formula and closed expressions for strong and electromagnetic decay widths and use these to analyze the available exper

C. Hanhart, U. van Kolck, G. A. Miller

Production of p-wave pions in nucleon-nucleon collisions is studied according to an improved power counting that embodies the constraints of chiral symmetry. Contributions from the first two non-vanishing orders are calculated. We find reasonable convergence and agreement with data for a spin-triplet cross section in $pp\to ppπ^0$,with no free parameters. Ag

Johan van de Leur

We show that all (n-component) KP tau-functions, which are related to the twisted loop group of $GL_n$, give solutions of the Darboux-Egoroff system of PDE&#39;s. Using the Geometry of the Grassmannian we construct from the corresponding wave function the deformed flat coordinates of the Egoroff metric and from this the corresponding solution of the Witten-D

Xavier Gracia, Jesus Marin-Solano, Miguel-C. Munoz-Lecanda

We give a geometric description of variational principles in mechanics, with special attention to constrained systems. For the general case of nonholonomic constraints, a unified variational approach is given, and the equations of motion of both vakonomic and nonholonomic frameworks are obtained. We study specifically the existence of infinitesimal variation

E. Brezin, S. Hikami

We have discussed earlier the correlation functions of the random variables $\det(\la-X)$ in which $X$ is a random matrix. In particular the moments of the distribution of these random variables are universal functions, when measured in the appropriate units of the level spacing. When the $\la$&#39;s, instead of belonging to the bulk of the spectrum, approac

Terence Tao

Recently Wolff obtained a nearly sharp $L^2$ bilinear restriction theorem for bounded subsets of the cone in general dimension. We obtain the endpoint of Wolff&#39;s estimate and generalize to the case when one of the subsets is large. As a consequence, we are able to deduce some nearly-sharp $L^p$ null form estimates.

S. Ovchinnikov

We show, following W. Holsztynski, that there exists a continuous metric d on the set of real numbers R such that any finite metric space is isometrically embeddable into (R,d).