December 2000 arXiv papers — page 12

D. J. Bicout, A. M. Berezhkovskii, Attila Szabo

The reaction A+B --> B is studied when the reactants diffuse in phase space, i.e. their dynamics is described by the Langevin equation. The steady-state rate constants are calculated for both the target (static A and mobile B's) and trapping (mobile A and static B's) problems when the reaction is assumed to occur at the first contact. For Brownian dy

Stephen Roberts, Boris Muzykantskii

Spectral decompositions for the evolution operator on an energy shell in phase space are constructed for the free motion on compact 2D surfaces of constant negative curvature. Applications to quantum chaos and in particular to the recently proposed ballistic sigma-model are briefly discussed.

R. Bulla, T. A. Costi, D. Vollhardt

Wilson's numerical renormalization group (NRG) method for the calculation of dynamic properties of impurity models is generalized to investigate the effective impurity model of the dynamical mean field theory at finite temperatures. We calculate the spectral function and self-energy for the Hubbard model on a Bethe lattice with infinite coordination numb

G. Parisi, M. Ratieville

We consider a class of random matching problems where the distance between two points has a probability law which, for a small distance l, goes like l^r. In the framework of the cavity method, in the limit of an infinite number of points, we derive equations for p_k, the probability for some given point to be matched to its k-th nearest neighbor in the optim

M. Jamet, M. Negrier, V. Dupuis, J. Tuaillon-Combes

A low concentration of cobalt clusters with a fcc structure and containing almost one thousand atoms are embedded in two different metallic matrices: platinum and niobium. Samples have been prepared using a co-deposition technique. Cobalt clusters preformed in the gas phase and matrix atoms are simultaneously deposited on a silicon substrate under Ultra High

A. V. Nikolaev, K. H. Michel

We have calculated the crystal electric field of TmTe (T>T_Q) and have obtained that the ground state of a Tm 4f hole is the $Γ_7$ doublet in agreement with Mossbauer experiments. We study the quadrupole interactions arising from quantum transitions of 4f holes of Tm. An effective attraction is found at the L point of the Brillouin zone, $\vec{q}_L$. Assumin

E. L. Nagaev

The possibility of the slab or stripe phase separation (alternating ferromagnetic highly- conductive and insulating antiferromagnetic layers) is proved for isotropic degenerate antiferromagnetic semiconductors. This type of phase separation competes with the droplet phase separation (ferromagnetic droplets in the antiferromagnetic host or vice versa). The in

P. C. Haljan, B. P. Anderson, I. Coddington, E. A. Cornell

A vortex in a condensate in a nonspherical trapping potential will in general experience a torque. The torque will induce tilting of the direction of the vortex axis. We observe this behavior experimentally and show that by applying small distortions to the trapping potential, we can control the tilting behaviour. By suppressing vortex tilt, we have been abl

Jean-Philippe Bouchaud, Irene Giardina, Marc Mezard

We propose a general interpretation for long-range correlation effects in the activity and volatility of financial markets. This interpretation is based on the fact that the choice between `active' and `inactive' strategies is subordinated to random-walk like processes. We numerically demonstrate our scenario in the framework of simplified market mod

U. Oberlack, E. Aprile, A. Curioni, K. Giboni

LXeGRIT is a balloon-borne Compton telescope for MeV gamma-ray astrophysics, based on a liquid xenon time projection chamber with charge and light readout. The energy and direction of an incident gamma-ray is reconstructed from the three-dimensional locations and energy deposits of individual interactions taking place in the homogeneous detector volume. Whil

Monica Colpi, Andrea Possenti, S. B. Popov, Fabio Pizzolato

The thermal, spin and magnetic evolution of neutron stars in the old low mass binaries is first explored. Recycled to very short periods via accretion torques, the neutron stars lose their magnetism progressively. If accretion proceeds undisturbed for 100 Myrs these stars can rotate close to break up with periods far below the minimum observed of 1.558 ms. W

Allyn F. Tennant, Kinwah Wu, Kajal K. Ghosh, Jeffery J. Kolodziejczak

The Chandra X-ray Observatory obtained a 50-ks observation of the central region of M81 using the ACIS-S in imaging mode. The global properties of the 97 x-ray sources detected in the inner 8.3x8.3 arcmin field of M81 are examined. Roughly half the sources are concentrated within the central bulge. The remainder are distributed throughout the disk with the b

J. C. B. Papaloizou, Caroline Terquem

Following the suggestion of Black (1997) that some massive extrasolar planets may be associated with the tail of the distribution of stellar companions, we investigate a scenario in which 5 < N < 100 planetary mass objects are assumed to form rapidly through a fragmentation process occuring in a disc or protostellar envelope on a scale of 100 au. These are a

T. R. Marsh

I consider the effect of the gravitational deflection of light upon the light curves of eclipsing binary stars, focussing mainly upon systems containing at least one white dwarf component. In absolute terms the effects are small, however they are strongest at the time of secondary eclipse when the white dwarf transits its companion, and act to reduce the dep

R. A. Johnson, S. F. Beaulieu, G. F. Gilmore, J. Hurley

We present colour-magnitude diagrams for two rich (~10^4 Msun) Large Magellanic Cloud star clusters with ages ~10^7 years, constructed from optical and near-infrared data obtained with the Hubble Space Telescope. These data are part of an HST project to study LMC clusters with a range of ages. In this paper we investigate the massive star content of the youn

Daniel A. Dale, Riccardo Giovanelli, Martha P. Haynes, Eduardo Hardy

The environmental dependencies of the characteristics of spiral galaxy rotation curves are studied in this work. We use our large, homogeneously collected sample of 510 cluster spiral galaxy rotation curves to test the claim that the shape of a galaxy&#39;s rotation curve strongly depends on its location within the cluster, and thus presumably on the strengt

M. R. Garcia, S. S. Murray, F. A. Primini, W. R. Forman

As part of the Chandra GTO program we are monitoring and surveying M31 using the HRC and ACIS cameras. These observations have resolved the nuclear X-ray source into five separate sources, one of which is very soft and may (or may not!) be associated with the central super-massive black hole. In addition, the superb spatial resolution and low scattering of t

B. Vollmer, M. Marcelin, P. Amram, C. Balkowski

New H-alpha Fabry-Perot interferometer observations of the Virgo cluster spiral galaxy NGC 4522 are presented. A velocity field up to a radius of 60&#39;&#39; was obtained. The observed rotation curve is symmetric. It is not perturbed in the inner disk. For radii >50&#39;&#39; it shows a solid body rotation. We compare these data with a numerical model which

Eric van der Swaluw, Abraham Achterberg, Yves A. Gallant

The cosmic-ray spectrum up to the knee ($E\sim 10^{15}$ eV) is attributed to acceleration processes taking place at the blastwaves which bound supernova remnants. Theoretical predictions give a similar estimate for the maximum energy which can be reached at supernova remnant shocks by particle acceleration. Electrons with energies of the order $\sim 10^{15}$

J Bordes, HM Chan, ST Tsou

A procedure is suggested for systematically narrowing the choice of possible primaries for (UHECR) air showers with energies beyond the Greisen-Zatsepin-Kuz&#39;min cut-off of $4 \times 10^{19} eV$.

L. Sidoli, A. N. Parmar, T. Oosterbroek, L. Stella

We have performed a detailed study of the broadband spectra of the luminous globular cluster X-ray sources using BeppoSAX. With the exception of X2127+119, located in NGC7078, all the other spectra are well represented by a two component model consisting of a disk-blackbody and Comptonized emission. The measured low-energy absorptions are in good agreement w

T. X. Thuan, Y. I. Izotov

A review of the latest measurements of the primordial abundances of the light nuclei D, 3He, 4He and 7Li is given. We discuss in particular the primordial abundance Yp of 4He as measured in blue compact dwarf galaxies. We argue that the best measurements now give a ``high&#39;&#39; value of Yp along with a ``low&#39;&#39; value of D/H, and that the two indep

Ortwin Gerhard, Andi Kronawitter, R. P. Saglia, Ralf Bender

Based on a uniform dynamical analysis of line-profile shapes for 21 luminous round elliptical galaxies, we have investigated the dynamical family relations of ellipticals: (i) The circular velocity curves (CVCs) of elliptical galaxies are flat to within ~10% for R>~0.2R_e. (ii) Most ellipticals are moderately radially anisotropic; their dynamical structure i

C. Done

I review observations of the X-ray spectra of Galactic Black Hole Candidates, and theoretical ideas as to how these can be produced. X-ray reflection should enable different source geometries to be distinguished, but the ionisation instability of X-ray irradiated material in hydrostatic equilibrium gives rise to large ambiguities in interpretation. It is not

R. Stehle, A. King, C. Rudge

We consider accretion discs in close binary systems. We show that heating of a disc at the impact point of the accretion stream contributes significantly to the local energy budget at its outer edge. As a result the thermal balance relation between local accretion rate and surface density (the `S-curve&#39;) changes; the critical mass transfer rate above whi

Heon-Young Chang

If a supermassive black hole resides in the centers of galaxies, there are several effects expected to be observed. It is likely that accretion disks are around the supermassive black hole. Stellar interactions with the accretion flows around the supermassive black hole play a role in that an flying-by star may cool a hot accretion disk as a result of Compto

Jeffrey A. Newman, Laura Ferrarese, Peter B. Stetson, Eyal Maoz

In a previous paper (Maoz et al. 1999), we reported a Hubble Space Telescope (HST) Cepheid distance to the galaxy NGC 4258 obtained using the calibrations and methods then standard for the Key Project on the Extragalactic Distance Scale. Here, we reevaluate the Cepheid distance using the revised Key Project procedures described in Freedman et al. (2001). The

W. L. Freedman, B. F. Madore, B. K. Gibson, L. Ferrarese

We present here the final results of the Hubble Space Telescope Key Project to measure the Hubble constant. We summarize our method, the results and the uncertainties, tabulate our revised distances, and give the implications of these results for cosmology. The analysis presented here benefits from a number of recent improvements and refinements, including (

Piero Madau, Francesco Haardt, Lucia Pozzetti

The optical/far-IR extragalactic background light (EBL) from both resolved and unresolved extragalactic sources is an indicator of the total luminosity of cosmic structures, as the cumulative emission from young and evolved galactic systems, as well as from active galactic nuclei (AGNs), is recorded in this radiation. This is a brief review of some of the im

Carl H. Gibson

Self-gravitational structure formation theory for astrophysics and cosmology is revised using nonlinear fluid mechanics. Gibson&#39;s 1996-2000 theory balances fluid mechanical forces with gravitational forces and density diffusion with gravitational diffusion at critical viscous, turbulent, magnetic, and diffusion length scales termed Schwarz scales. Instab

Ralf Hofmann, Panagiota Kanti, Maxim Pospelov

We study the stabilization of one spatial dimension in (p+1+1)-dimensional spacetime in the presence of $p$-dimensional brane(s), a bulk cosmological constant and the Casimir force generated by a conformally coupled scalar field. We find general static solutions to the metric which require the fine-tuning of the inter-brane distance and the bulk cosmological

Avshalom C. Elitzur, Shahar Dolev

Any theory that states that the basic laws of physics are time-symmetric must be strictly deterministic. Only determinism enables time reversal of entropy increase. A contradiction therefore arises between two statements of Hawking. A simulation of a system under time reversal shows how an intrinsic time arrow re-emerges, destroying the time reversal, when e

A. Ali, A. Ya. Parkhomenko

We study the $η^\prime g^* g^*$ vertex for arbitrary gluon virtualities in the time-like and space-like regions, using the perturbative QCD hard scattering approach and an input wave-function of the $η^\prime$-meson consistent with the measured $η^\prime γ^* γ$ transition form factor. The contribution of the gluonic content of the $η^\prime$-meson is taken i

Mao-Zhi Yang, Ya-Dong Yang

We have studied charmless two-body B decays involving $η$ and $η&#39;$ in the framework of QCD improved factorization appraoch. The spectator hard scattering mechanism for $η&#39;$ production have been re-examined and extended, which contributions are incorporated consistently into the factorizable leading contributions. It is found that the conventional mec

V. Karimipour, A. Ramezanpour

We analyze the effect of correlations in a simple model of small world network by obtaining exact analytical expressions for the distribution of shortest paths in the network. We enter correlations into a simple model with a distinguished site, by taking the random connections to this site from an Ising distribution. Our method shows how the transfer matrix

W. Bietenholz, J. Nishimura

The Ginsparg-Wilson relation, if written in a suitable form, can be used as a condition for lattice Dirac operators of massless fermions also in odd dimensions. The fermion action with such a Dirac operator is invariant under a generalized parity transformation, which reduces to the ordinary parity transformation in the (naive) continuum limit. The fermion m

Vania E. Barlette, Marcelo M. Leite, Sadhan K. Adhikari

A self-contained discussion of nonrelativistic quantum scattering is presented in the case of central potentials in one space dimension, which will facilitate the understanding of the more complex scattering theory in two and three dimensions. The present discussion illustrates in a simple way the concept of partial-wave decomposition, phase shift, optical t

S. J. van Enk, O. Hirota

When a superposition $(|α>-|-α>)$ of two coherent states with opposite phase falls upon a 50-50 beamsplitter, the resulting state is entangled. Remarkably, the amount of entanglement is exactly 1 ebit, irrespective of $α$, as was recently discovered by O. Hirota and M. Sasaki. Here we discuss decoherence properties of such states and give a simple protocol t

Mang Feng

Raman interaction of a trapped ultracold ion with two traveling wave lasers has been used extensively in the ion trap experiments. We solve this interaction in the absence of the rotating wave approximation by a continued fraction, without considering the restriction of the Lamb-Dicke limit and the weak excitation regime. Some interesting characteristics of

Richard Jozsa

Amongst the most remarkable successes of quantum computation are Shor&#39;s efficient quantum algorithms for the computational tasks of integer factorisation and the evaluation of discrete logarithms. In this article we review the essential ingredients of these algorithms and draw out the unifying generalization of the so-called abelian hidden subgroup probl

Abir Bandyopadhyay, Jagdish Rai

A simple, and elegant geometrical representation is developed to describe the concept of coherence and squeezing for angular momentum operators. Angular momentum squeezed states were obtained by applying Bogoliubov transformation on the angular momentum coherent states in Schwinger representation [Phys. Rev. {\bf{A 51}} (1995)]. We present the geometrical ph

Martin Schaden, Larry Spruch

We study the dependence on the temperature T of Casimir effects for a range of systems, and in particular for a pair of ideal parallel conducting plates, separated by a vacuum. We study the Helmholtz free energy, combining Matsubara&#39;s formalism, in which the temperature appears as a periodic Euclidean fourth dimension of circumference 1/T, with the semic

Sadhan K. Adhikari

We report results of differential cross sections for elastic scattering, target-elastic Ps excitations and target-inelastic excitation of hydrogen in a five-state coupled-channel model allowing for Ps(1s)H(2s,2p) and Ps(2s,2p)H(1s) excitations using a recently proposed time-reversal-symmetric regularized electron-exchange model potential. The present model y

P. K. Biswas, Sadhan K. Adhikari

The scattering of ortho positronium (Ps) by H$_2$ has been investigated using a three-Ps-state [Ps(1s,2s,2p)H$_2($X $^1Σ_g^+$)] coupled-channel model and using Born approximation for higher excitations and ionization of Ps and B $^1Σ_u^+$ and b $^3Σ_u^+$ excitations of H$_2$. We employ a recently proposed time-reversal-symmetric nonlocal electron-exchange mo

Renat A. Sultanov, Sadhan K. Adhikari

We perform dynamical calculations of direct muon-transfer rates from thermalized muonic hydrogen isotopes to bare nuclei C$^{6+}$ and O$^{8+}$. For these three-body charge-transfer reactions with Coulomb interaction in the final state we use two-component integro-differential Faddeev-Hahn-type equations in configuration space using close-coupling approximati

Sadhan K. Adhikari

Scattering of positronium (Ps) by helium atom has been investigated in a three-Ps-state coupled-channel model including Ps(1s,2s,2p) states using a recently proposed time-reversal-symmetric regularized electron-exchange model potential. Specifically, we report results of differential cross sections for elastic scattering and target-elastic Ps excitations. We

A. Yu. Illarionov, G. I. Lykasov

The elastic backward proton-deuteron scattering is analyzed within a fully covariant approach based on the invariant expansion of the reaction amplitude. The method of calculation of any observables for any reaction mechanism is developed. The cross section and spin observables, like tensor analyzing power and polarization transfer coefficient etc., are inve

S. Moghimi-Araghi, S. Rouhani, M. Saadat

We propose a general frame work for deriving the OPEs within a logarithmic conformal field theory (LCFT). This naturally leads to the emergence of a logarithmic partner of the energy momentum tensor within an LCFT, and implies that the current algebra associated with an LCFT is expanded. We derive this algebra for a generic LCFT and discuss some of its impli

D. J. Broadhurst, D. Kreimer

The Hopf algebra of undecorated rooted trees has tamed the combinatorics of perturbative contributions, to anomalous dimensions in Yukawa theory and scalar $ϕ^3$ theory, from all nestings and chainings of a primitive self-energy subdivergence. Here we formulate the nonperturbative problems which these resummations approximate. For Yukawa theory, at spacetime

A. Gorsky, A. Mironov

The review studies connections between integrable many-body systems and gauge theories. It is shown how the degrees of freedom in integrable systems are related with topological degrees of freedom in gauge theories. The relations between families of integrable systems and N=2 supersymmetric gauge theories are described. It is explained that the degrees of fr

Nora Brambilla

Heavy quark bound states are used as significative probes of the QCD vacuum and the mechanism of confinement.

F. V. Tkachov

This postscriptum to the theory of jet definition [hep-ph/9901444] summarizes the points which did not find their way into the main text.

D. Yu. Bardin, L. V. Kalinovskaya, F. V. Tkachov

We report our experiences with the generalized integration-by-parts algorithm [hep-ph/9609429] in the context of calculations of a realistic one-loop subset of diagrams.

G. M. Shore

The nature of superluminal photon propagation in the gravitational field describing radiation from a time-dependent, isolated source (the Bondi-Sachs metric) is considered in an effective theory which includes interactions which violate the strong equivalence principle. Such interactions are, for example, generated by vacuum polarisation in conventional QED

S. K. Moayedi, F. Darabi

Three families of exact solutions for 2-dimensional gravity minimally coupled to electrodynamics are obtained in the context of ${\cal R}=T$ theory. It is shown, by supersymmetric formalism of quantum mechanics, that the quantum dynamics of a neutral bosonic particle on static backgrounds with both varying curvature and electric field is exactly solvable.

Ignacio Olabarrieta

We perform a numerical study of the critical regime for the general relativistic collapse of collisionless matter in spherical symmetry. The evolution of the matter is given by the Vlasov equation (or Boltzmann equation) and the geometry by Einstein&#39;s equations. This system of coupled differential equations is solved using a particle-mesh (PM) method. Th

Colin Denniston, Enzo Orlandini, J. M. Yeomans

Lattice Boltzmann simulations are used to explore the behavior of liquid crystals subject to Poiseuille flow. In the nematic regime at low shear rates we find two possible steady state configurations of the director field. The selected state depends on both the shear rate and the history of the sample. For both director configurations there is clear evidence

Michael Stone

I provide a pedagogical introduction to the notion of pseudomomentum for waves in a medium, and show how changes in pseudomomentum may sometimes be used to compute real forces. I then explain how these ideas apply to sound waves in a fluid. When the background fluid is in motion, the conservation laws for pseudomomentum and pseudoenergy are most easily obtai

M. Mueller, D. Gorokhov, G. Blatter

Using a dynamic functional renormalization group treatment of driven elastic interfaces in a disordered medium, we investigate several aspects of the creep-type motion induced by external forces below the depinning threshold $f_c$: i) We show that in the experimentally important regime of forces slightly below $f_c$ the velocity obeys an Arrhenius-type law $

A. B. Zorin

A quantum-limited electrometer based on charge modulation of the Josephson supercurrent in the Bloch transistor inserted into a superconducting ring is proposed. As this ring is inductive coupled to a high-Q resonance tank circuit, the variations of the charge on the transistor island (input signal) are converted into variations of amplitude and phase of rad

S. H. Curnoe, A. E. Jacobs

We study numerically the time evolution of two-dimensional (2D) domain patterns in proper tetragonal-orthorhombic (T-O) ferroelastics. Our results, found by solving equations of motion derived from classical elasticity theory, disagree with those found by other methods. We study first the growth of the 2D nucleus resulting from homogeneous nucleation events.

Veit Elser

A recent proposal by Maris[1], that single electron bubbles in helium might fission into separate, particle-like entities, does not properly take into account the failure of the adiabatic approximation when, due to tunneling, there is a long electronic time scale. The point along the fission pathway of a photoexcited p-state bubble, where the adiabatic appro

D. E. Harris

A list is presented of known extragalactic radio jets which also have associated X-ray emission. The canonical emission processes for the production of X-rays are reviewed and the sources are categorized on the basis of our current understanding. Although it seems clear that the X-ray emission is non-thermal, the two competing processes, synchrotron and inve

E. Xanthopoulos, I. W. A. Browne, A. R. Patnaik, P. N. Wilkinson

We present VLA and MERLIN monitoring data of the JVAS gravitational lens system B1030+074. The system was monitored with the VLA from February 1998 to October 1998 at 8.4-GHz during which the VLA was at its A, BnA and B configuration. The 47 epochs of observations have an average spacing of approximately 5 days. Ten MERLIN snapshots were obtained in the L-ba

Fabio Bresolin, Rolf-Peter Kudritzki, Roberto H. Mendez, Norbert Przybilla

Multi-object spectroscopic observations of blue supergiants in NGC 3621, a spiral galaxy at a distance of 6.7 Mpc, carried out with the ESO VLT and FORS are presented. We demonstrate the feasibility of quantitative stellar spectroscopy at distances approaching a ten-fold increase over previous investigations by determining chemical composition, stellar param

M. Faber, A. N. Ivanov, N. I. Troitskaya

We evaluate the evolution operator Z_Reg(R_2,R_1) introduced by Diakonov and Petrov for the definition of the Wilson loop in terms of a path integral over gauge degrees of freedom. We use the procedure suggested by Diakonov and Petrov (Phys. Lett. B224 (1989) 131) and show that the evolution operator vanishes.

Mei Xiaochun

The asymmetrical path interference test of light is put forward in the paper. In the test, two different results would arise under the same experimental conditions if light is regarded as wave or particle. Therefore, the test can help us to comprehend which concept, wave or particle, is more essential for micro-particles.

Mei Xiaochun

It is pointed that we now actually have no enough proofs to prove that time reversal symmetry is universally obeyed in the processes of particle interactions. The analyses show that the time reversal symmetry is obviously violated at least in the decay processes of particles, especially in the decay processes of strange particles, and some resonance states w

Alexandros Pertsinidis, X. S. Ling

We demonstrate a novel method of introducing point defects (mono and di-vacancies) in a confined mono-layer colloidal crystal by manipulating individual particles with optical tweezers. Digital video microscopy is used to study defect dynamics in real space and time. We analyze the topological arrangements of the particles in the defect core and establish th

A. Konechny, A. Schwarz

Noncommutative geometry is based on an idea that an associative algebra can be regarded as &#34;an algebra of functions on a noncommutative space&#34;. The major contribution to noncommutative geometry was made by A. Connes, who, in particular, analyzed Yang-Mills theories on noncommutative spaces, using important notions that were introduced in his papers (

Avshalom C. Elitzur, Shahar Dolev

Time&#39;s apparent passage has long been debated by philosophers, with no decisive argument for or against its objective existence. In this paper we show that introducing the issue of determinism gives the debate a new, empirical twist. We prove that any theory that states that the basic laws of physics are time-symmetric must be strictly deterministic. It

D. L. Zhou, S. Y. Yu, C. P. Sun

A practical method is developed to deal with the second quantization of the many-body system containing the composite particles. In our treatment, the modes associated with composite particles are regarded approximately as independent ones compared with those of unbound particles. The field operators of the composite particles thus arise naturally in the sec

Edo Waks, Assaf Zeevi, Yoshihisa Yamamoto

Security of the Ekert protocol is proven against individual attacks where an eavesdropper is allowed to share any density matrix with the two communicating parties. The density matrix spans all of the photon number states of both receivers, as well as a probe state of arbitrary dimensionality belonging to the eavesdropper. Using this general eavesdropping st

Shahar Dolev, Avshalom C. Elitzur

It is probably not a coincidence that two of the pioneers of thermodynamics, Helmholtz and Mayer, were physicians. Thermodynamics studies the transformations of energy, and such transformations ceaselessly take place in all living systems (probably with important differences between the states of health and disease). Moreover, thermodynamics studies the elus

Metod Saniga

It is hypothetized that the algebra of the configuration of twenty-seven lines lying on a general cubic surface underlines the dimensional hierarchy of heterotic string spacetimes.

Tapas Sil, B. K. Agrawal, J. N. De, S. K. Samaddar

The equation of state (EOS) of finite nuclei is constructed in the relativistic Thomas-Fermi theory using the non-linear $σ-ω-ρ$ model. The caloric curves are calculated by confining the nuclei in the freeze-out volume taken to be a sphere of size about 4 to 8 times the normal nuclear volume. The results obtained from the relativistic theory are not signific

S. Kamvissis, K. T. -R. McLaughlin, P. D. Miller

We present a new generalization of the steepest descent method introduced by Deift and Zhou for matrix Riemann-Hilbert problems and use it to study the semiclassical limit of the focusing nonlinear Schroedinger equation with real analytic, even, bell-shaped initial data. We provide explicit strong locally uniform asymptotics for a sequence of exact solutions

Madalena Chaves, Eduardo D. Sontag

One of the most interesting questions in control theory is that of constructing observers. Observers compute estimates of the internal states of a dynamical system, using data provided by measurement probes or partial state information. For linear systems, Luenberger observers (also known as &#34;deterministic Kalman filters&#34; since they amount to Kalman

Vincenzo Ancona, Marco Maggesi

In their paper &#34;Quantum cohomology of projective bundles over $P^n$&#34; (Trans. Am. Math. Soc. (1998)350:9 3615-3638) Z.Qin and Y.Ruan introduce interesting techniques for the computation of the quantum ring of manifolds which are projectivized bundles over projective spaces; in particular, in the case of splitting bundles they prove under some restrict

J. L. Lucio M., J. Pestieau

We consider the problem of propagation of an unstable particle in the framework of Quantum Field Theory. Using unitarity, we show that a real renormalization constant free of threshold singularities naturally arises.

Pavel Fileviez Perez

The extra particles provided by Supersymmetry (SUSY) appear as natural candidates for exotica such as the missing Dark Matter of the Universe. The particle candidates for Dark Matter, and the basic elements of the minimal supersymmetric extension of the Standard Model are reviewed. The needed elements to compute the neutralino counting rate are given, consid

Howard Baer, Csaba Balazs, Stefan Hesselbach, J. Kenichi Mizukoshi

There are many models with non-universal soft SUSY breaking sfermion mass parameters at the grand unification scale. Even in the mSUGRA model scalar mass unification might occur at a scale closer to M_Planck, and renormalization effects would cause a mass splitting at M_GUT. We identify an experimentally measurable quantity Delta that correlates strongly wit

J. J. Kirchner, U. J. Becker, R. B. Dinner, K. J. Fidkowski

Modern detectors such as ATLAS use pressurized drift tubes to minimize diffusion and achieve high coordinate accuracy. However, the coordinate accuracy depends on the exact knowledge of converting measured times into coordinates. Linear space-time relationships are best for reconstruction, but difficult to achieve in the $E \propto \frac{1}{r}$ field. Previo

2 collaboration

Using 15.1 pb^{-1} of data collected by CMD-2 in the phi-meson energy range, the branching ratios of the following conversion decays have been measured: B(ϕ\toηe^+e^-) = (1.14\pm0.10\pm0.06)\cdot10^{-4}, B(η\to e^+e^-γ) = (7.10\pm0.64\pm0.46)\cdot10^{-3}, B(η\toπ^+π^-e^+e^-) = (3.7^{+2.5}_{-1.8}\pm0.3)\cdot10^{-4}. The upper limits for the following rare con

Z. G. Zhao

We report preliminary $R$ values for all 85 energy points scanned in the energy region of 2-5 GeV with the upgraded Beijing Spectrometer (BESII) at the Beijing Electron Positron Collider (BEPC). The typical uncertainty on the R values we measured is about 7%. The new R values have a significant impact on the predicted mass of the Higgs coming from the global

James Weatherall

The measurement of sin2beta by the BABAR experiment, where beta is one of the angles of the Unitarity Triangle, is described. Some prospects for the future of the measurement are also discussed.

Avshalom C. Elitzur, Shahar Dolev

Rebilas argues that time-reversal can occur even in an indeterministic system. This hypothesis is untestable, hence lying beyond physics.

Dieter Kranzlmueller, Christian Schaubschlaeger, Jens Volkert

Debugging parallel and distributed programs is a difficult activitiy due to the multiplicity of sequential bugs, the existence of malign effects like race conditions and deadlocks, and the huge amounts of data that have to be processed. These problems are addressed by the Monitoring And Debugging environment MAD, which offers debugging functionality based on

Marcus Hutter

Decision theory formally solves the problem of rational agents in uncertain worlds if the true environmental probability distribution is known. Solomonoff&#39;s theory of universal induction formally solves the problem of sequence prediction for unknown distribution. We unify both theories and give strong arguments that the resulting universal AIXI model beh

Parthapratim Biswas, G. T. Barkema, Normand Mousseau, W. F. van der Weg

While recent work towards the development of tight-binding and ab-initio algorithms has focused on molecular dynamics, Monte Carlo methods can often lead to better results with relatively little effort. We present here a multi-step Monte Carlo algorithm that makes use of the possibility of quickly evaluating local energies. For the thermalization of a 1000-a

Adam Ponzi

Single index financial market models cannot account for the empirically observed complex interactions between shares in a market. We describe a multi-share financial market model and compare characteristics of the volatility, that is the standard deviation of the price fluctuations, with empirical characteristics. In particular we find its probability distri

M. H. Ghatee, H. Shams-Abadi

The linear exp6 isotherm is presented as an approach to the thermodynamic properies of liquid alkali metals over the whole liquid range including metal-nonmetal transition. The exp6 pair interaction potential is applied to approach the underlying interplay between the characteristic soft repulsive intercation in dense, large attractive interaction in the exp

Beom Jun Kim, Mahn-Soo Choi, Petter Minnhagen, Gun Sang Jeon

We consider a Josephson-junction ladder in an external magnetic field with half flux quantum per plaquette. When driven by external currents, periodic in time and staggered in space, such a fully frustrated system is found to display spatiotemporal stochastic resonance under the influence of thermal noise. Such resonance behavior is investigated both numeric

Sudip Chakravarty, Steven A. Kivelson

On the basis of an analysis of theoretical and numerical studies of model systems, and of experiments on superconductivity in doped C$_{60}$, polyacenes, and the cuprate high temperature superconductors, we propose that a purely electronic mechanism of superconductivity requires structures at an intermediate or mesoscale. Specifically, we address the crucial

Amit Ghosal, Mohit Randeria, Nandini Trivedi

We study a simple model of a two-dimensional s-wave superconductor in the presence of a random potential in the regime of large disorder. We first use the Bogoliubov-de Gennes (BdG) approach to show that, with increasing disorder the pairing amplitude becomes spatially inhomogeneous, and the system cannot be described within conventional approaches for study

Niels Asger Mortensen, Karsten Flensberg, Antti-Pekka Jauho

We present a theory for Coulomb drag between two mesoscopic systems. Our formalism expresses the drag in terms of scattering matrices and wave functions, and its range of validity covers both ballistic and disordered systems. The consequences can be worked out either by analytic means, such as the random matrix theory, or by numerical simulations. We show th

David W. Hogg

Formulae for the line-of-sight and transverse comoving distances, proper motion distance, angular diameter distance, luminosity distance, k-correction, distance modulus, comoving volume, lookback time, age, and object intersection probability are all given, some with justifications. Some attempt is made to rationalize disparate terminologies, or at least abu

R. K. Zamanov, P. Reig, J. Marti, M. J. Coe

We present a comparative study of the circumstellar disks in Be/X-ray binaries and isolated Be stars based upon the H-alpha emission line. From this comparison it follows that the overall structure of the disks in the Be/X-ray binaries is similar to the disks of other Be stars, i.e. they are axisymmetric and rotationally supported. The factors for the line b

W. J. Altenhoff, K. M. Menten, F. Bertoldi

Using the Max-Planck Millimeter Bolometer Array (MAMBO) at the IRAM 30m telescope we detected emission at 250 GHz from the Centaur Chariklo (1997 CU26). The observed continuum flux density implies a photometric diameter of 273 km. The resulting geometric albedo is 0.055, somewhat higher than expected from a comparison with most of the other few Centaurs and

Sofia Feltzing, Guillermo Gonzalez

We provide detailed abundance analyses of 8 candidate super-metal-rich stars. Five of them are confirmed to have [Fe/H] > 0.2 dex, the generally-accepted limit for super-metal-richness. Furthermore, we derive abundances of several elements and find that the stars follow trends seen in previous studies of metal-rich stars. Ages are estimated from isochrones a