March 2002 arXiv papers — page 26

Martin A. Guerrero, Robert A. Gruendl, You-Hua Chu

XMM-Newton EPIC observations of the planetary nebula (PN) NGC 7009, the Saturn Nebula, have detected extended X-ray emission in its central cavity. The diffuse X-ray emission must originate in the shocked fast stellar wind. The spectra show that the temperature of the hot gas is 1.8*10^6 K. The rms density derived from the volume emission measure is a few te

Laura Ferrarese

The purpose of this contribution is to review the current status of black hole demographics in light of recent advances in the study of high redshift QSOs (section 2), local AGNs (section 3) and local quiescent galaxies (section 4). I will then outline the prospects for future progress (section 5), and discuss what I believe will be the challenges for the ye

Henric Krawczynski

We report on spectroscopic imaging observations of the nearby (z=0.022) galaxy cluster 3C 129 performed with the ACIS detector on board of the Chandra X-ray observatory. Applying a deprojection analysis which fully takes into account the spatially resolved X-ray energy spectra we investigate the radial variation of temperature and particle density of the Int

Stephen L. W. McMillan

The past few years have seen dramatic improvements in the scope and realism of star cluster simulations. Accurate treatments of stellar evolution, coupled with robust descriptions of all phases of binary evolution, have been incorporated self-consistently into several dynamical codes, allowing for the first time detailed study of the interplay between stella

G. L. Israel, W. Hummel, S. Covino, S. Campana

We carried out optical observations of the field of the X-ray pulsator RXJ0806.3+1527. A blue V=21.1 star was found to be the only object consistent with the X-ray position. VLT FORS spectra revealed a blue continuum with no intrinsic absorption lines. Broad (v~1500 km/s), low equivalent width (about -1/-6A) emission lines from the HeII Pickering series were

Roberto G. Abraham, Sidney van den Bergh

The morphologies of disk galaxies begin to deviate systematically from those of nearby galaxies at surprisingly low redshifts, possibly as low as z=0.3. This corresponds to a time ~3.5 Gyr in the past, which is only one quarter of the present age of the Universe. Beyond z = 0.5 (a look-back time of 5 Gyr) the effects of evolution on spiral structure are rath

E. Di Carlo, F. Massi, G. Valentini, A. Di Paola

Optical and near-infrared light curves of the Type IIn supernova 1999el in NGC 6951 are presented. A period of 220 days (416 days in the near-infrared) is covered from the first observation obtained a few days before maximum light. Spectroscopic observations are also discussed. Using as a distance calibrator the Type Ia SN 2000E, which occurred some months l

F. M. Zerbi, P. Spano', P. Conconi, E. Molinari

A way to fully exploit the large collecting area of modern 8-10m class telescopes is high resolution spectroscopy. Many astrophysical problems from planetary science to cosmology benefit from spectroscopic observations at the highest resolution currently achievable and would benefit from even higher resolutions. Indeed in the era of 8-10m class telescopes no

A. Pizzella, E. M. Corsini, L. Morelli, M. Sarzi

We report evidence for nuclear stellar disks in 3 early-type spirals, namely NGC 1425, NGC 3898 and NGC 4698, revealed by WFPC2/F606W images out of a sample of 38 spiral galaxies, selected from the Hubble Space Telescope Data Archive. Adopting the photometric method introduced by Scorza & Bender we derived their central surface brightness and scalelength by

Paola Marigo

We investigate the effects of molecular opacities on the evolution of TP-AGB stars that experience the third dredge-up, i.e. with surface abundances of carbon and oxygen varying with time. To this aim, a routine is constructed to derive the molecular concentrations through dissociation equilibrium calculations, and estimate the opacities due to H2, H2O, OH,

S. Takagi, H. Murakami, K. Koyama

We report the X-ray population study in the giant molecular cloud Sagittarius B2 (SgrB2). More than a dozen of X-ray cloud members (and candidates) are discovered with Chandra. Two bright X-ray sources are located near Sgr B2 Main, the most copious complex of the ultra compact HII sources. The X-ray spectra are fitted with a thin thermal plasma model of 5-10

F. M. Zerbi, G. Chincarini, G. Ghisellini, M. Rodono'

Observations of the prompt afterglow of Gamma Ray Burst events are unanimously considered of paramount importance for GRB science and related cosmology. Such observations at NIR wavelengths are even more promising allowing one to monitor high-z Ly-alpha absorbed bursts as well as events occurring in dusty star-forming regions. In these pages we present REM (

T. Harko, K. S. Cheng

The Chandrasekhar limit for strange stars described by a linear equation of state (describing quark matter with density-dependent quark masses) is evaluated. The maximum mass and radius of the star depend on the fundamental constants and on the energy density of the quark matter at zero pressure. By comparing the expression for the mass of the star with the

Andrei Gruzinov

Effective heat conduction in a random variable magnetic field should be equal to one third of the Spitzer's value. Recent observations indicate that this heat conduction is sufficient to account for the bremsstrahlung in cooling X-ray clusters.

Mitchell C. Begelman

Radiation pressure-dominated accretion disks are predicted to exhibit strong density inhomogeneities on scales much smaller than the disk scale height, due to the nonlinear development of photon bubble instability. Radiation would escape from such a "leaky" disk at a rate higher than that predicted by standard accretion disk theory. The disk scale he

Adrian A. Dragulescu, Victor M. Yakovenko

We study the Heston model, where the stock price dynamics is governed by a geometrical (multiplicative) Brownian motion with stochastic variance. We solve the corresponding Fokker-Planck equation exactly and, after integrating out the variance, find an analytic formula for the time-dependent probability distribution of stock price changes (returns). The form

Aditi Sen De, Ujjwal Sen

We use a recently proposed measure of quantum correlations (work deficit), to measure the strength of the nonlocality of an equal mixture of two bipartite, orthogonal, but locally indistinguishable separable states. This gives supporting evidence of nonzero value for a separable state, for this measure of nonlocality. We also show that this measure of quantu

M. Banados, O. Chandia, A. Ritz

In two dimensional conformal field theory the generating functional for correlators of the stress-energy tensor is given by the non-local Polyakov action associated with the background geometry. We study this functional holographically by calculating the regularized on-shell action of asymptotically AdS gravity in three dimensions, associated with a specifie

Johanna Erdmenger, Zachary Guralnik, Ingo Kirsch

We study four-dimensional superconformal field theories coupled to three-dimensional superconformal boundary or defect degrees of freedom. Starting with bulk N=2, d=4 theories, we construct abelian models preserving N=2, d=3 supersymmetry and the conformal symmetries under which the boundary/defect is invariant. We write the action, including the bulk terms,

Z. Berezhiani, A. Gorsky, I. I. Kogan

In this note we discuss the possibility to get a time rather than space in the scenario of (de)construction of new dimension.

Vladimir Privman

In systems considered for quantum computing, i.e., for control of quantum dynamics with the goal of processing information coherently, decoherence and deviation from pure quantum states, are the main obstacles to fault-tolerant error correction. At low temperatures, usually assumed in quantum computing designs, some of the accepted approaches to evaluation o

Helge Øystein Maakestad

Let H be a closed subgroup of a linear algebraic group G defined over a field F. There is an equivalence of categories between the category of linear finite-dimensional representations of H and the category of finite rank G-homogeneous vectorbundles on G/H. In this short note we study this correspondence for the sheaves of principal parts (=jetbundles) of ho

M. Fujiwara, T. Kawabata, P. Mohr

The $α$-decay rates for the nuclides $^{168,170,171,172,173,174,176}$Yb and $^{148,150,152,154}$Gd have been estimated from transmission probabilities in a systematic $α$-nucleus potential and from an improved fit to $α$-decay rates in the rare-earth mass region. Whereas $α$-decay of $^{152}$Gd in natural gadolinium is a severe obstacle for the use of gadoli

Keshav Dasgupta, Carlos Herdeiro, Shinji Hirano, Renata Kallosh

A proposal is made for a cosmological D3/D7 model with a constant magnetic flux along the D7 world-volume. It describes an N=2 gauge model with Fayet-Iliopoulos terms and the potential of the hybrid P-term inflation. The motion of the D3-brane towards D7 in a phase with spontaneously broken supersymmetry provides a period of slow-roll inflation in the de Sit

P. Danielewicz

Extraction of bulk nuclear properties by comparing reaction observables to results from semiclassical transport-model simulations is discussed. Specific properties include the nuclear viscosity, incompressibility and constraints on the nuclear pressure at supranormal densities.

Nikita Sidorov

This survey paper is aimed to describe a relatively new branch of symbolic dynamics which we call Arithmetic Dynamics. It deals with explicit arithmetic expansions of reals and vectors that have a "dynamical" sense. This means precisely that they (semi-) conjugate a given continuous (or measure-preserving) dynamical system and a symbolic one. The cla

F. Bakharev, K. Kokhas, F. Petrov

We prove configuration theorems that generalize the Desargues, Pascal, and Pappus theorems. Our generalization of the Desargues theorem allows us to introduce the structure of an Abelian group on the (properly extended) set of triangles which are perspective from a point. In barycentric coordinates, the corresponding group operation becomes the addition in R

Olaf Müller

A new class of 3-manifold invariants is constructed from representations of the category of framed tangles.

Ilya Kapovich

We show that if $H$ is a quasiconvex subgroup of infinite index in a non-elementary hyperbolic group $G$ then the Schreier coset graph $X$ for $G$ relative to $H$ is non-amenable (that is, $X$ has positive Cheeger constant). We present some corollaries regading the Martin boundary and Martin compactification of $X$ and the co-growth of $H$ in $G$.

Fritz DeJongh

We have investigated the physics potential of very long baseline experiments designed to measure nu_mu to nu_e oscillation probabilities. The principles of our design are to tune the beam spectrum to the resonance energy for the matter effect, and to have the spectrum cut off rapidly above this energy. The matter effect amplifies the signal, and the cut-off

James V. Lindesay, Harry L. Morrison

A system of equations is developed for a fluid with non-abelian local gauge symmetry. Anisotropy is introduced by requiring that the symmetry breaking preserves a restricted local gauge symmetry about a given direction in the gauge parameter space. A set of equations is proposed for the 3He-A system. Topological quantization conditions are discussed.

Marcus Kasner

Two-dimensional interacting electron systems become strongly correlated if the electrons are subject to a perpendicular high magnetic field. After introducing the physics of the quantum Hall regime the incompressible many- particle ground state and its excitations are studied in detail at fractional filling factors for spin-polarized electrons. The spin degr

D. Andrienko, G. Germano, M. P. Allen

We propose a simple and reliable method to measure the liquid crystal surface anchoring strength by molecular simulation. The method is based on the measurement of the long-range fluctuation modes of the director in confined geometry. As an example, molecular simulations of a liquid crystal in slab geometry between parallel walls with homeotropic anchoring h

Kamal Krishna Saha, Tanusri Saha-Dasgupta, Abhijit Mookerjee, Sonali Saha

In this communication we suggest a formulation of the optical conductivity as a convolution of an energy resolved joint density of states and an energy-frequency labelled transition rate. Our final aim is to develop a scheme based on the augmented space recursion for random systems. In order to gain confidence in our formulation, we apply the formulation to

Yukitoshi Motome, Nobuo Furukawa

Spin excitation spectrum of the double-exchange model is studied in the presence of randomness. Spin wave approximation in the ground state shows that the randomness significantly modifies the spectrum from the cosine-like one in the pure system to that with anomalies such as broadening, anti-crossing and gap opening. The origin of anomalies is speculated to

K. V. Krutitsky, K. -P. Marzlin, J. Audretsch

Starting from the first principles of nonrelativistic QED we have derived the system of Maxwell-Schrödinger equations, which can be used for theoretical description of atom optical phenomena at high densities of atoms and high intensities of the laser radiation. The role of multiple atomic transitions between ground and excited states in atom optics has been

H. B. Ann

We have conducted a $UBVRI$ and $H_α$ CCD photometry of 5 barred galaxies, NGC 2523, NGC 2950, NGC 3412, NGC 3945 and NGC 5383, along with SPH simulations, in order to understand the origin of young stellar populations in the nuclei of barred galaxies. The $H_α$ emissions which are thought to be emitted by young stellar populations are either absent or stron

H. B. Ann, S. H. Lee, H. Sung, M. G. Lee

We have initiated a long-term project, the BOAO photometric survey of open clusters, to enlarge our understanding of galactic structure using UBVI CCD photometry of open clusters which have been little studied before. This is the second paper of the project in which we present the photometry of 12 open clusters. We have determined the cluster parameters by f

H. B. Ann

We performed SPH simulations to study the nuclear morphology of a barred galaxy NGC 4314. We have constructed the mass models based on the results of a profile decomposition into disk, bulge, and bar components. Our models have three different nuclear structures according to the assumption about the nuclear bar: no nuclear bar, a synchronous nuclear bar and

A. Comastri, M. Brusa, P. Ciliegi, M. Mignoli

Multiwavelength observations of the hard X-ray selected sources by Chandra and XMM-Newton surveys have significantly improved our knowledge of the objects responsible of the hard X-ray background. A surprising finding is the discovery of a population of optically dull, X-ray bright galaxies emerging at 2-10 keV fluxes of the order of 10^{-14} erg cm^{-2} s^{

Ramesh Narayan, Eliot Quataert, Igor V. Igumenshchev, Marek A. Abramowicz

Radiatively inefficient accretion flows onto black holes are unstable due to both an outwardly decreasing entropy (`convection') and an outwardly decreasing rotation rate (the `magnetorotational instability'; MRI). Using a linear magnetohydrodynamic stability analysis, we show that long-wavelength modes are primarily destabilized by the entropy gradi

NuTeV Collaboration, G. P. Zeller, K. S. McFarland

The NuTeV collaboration recently reported a value of sin2thetaW measured in neutrino-nucleon scattering that is 3 standard deviations above the standard model prediction. This result is derived assuming that (1) the strange sea is quark-antiquark symmetric, s(x)=sbar(x), and (2) up and down quark distributions are symmetric under the simultaneous interchange

Kim Hyeon-Deuk, Hisao Hayakawa

We examine information theory using the steady-state Boltzmann equation. In a nonequilibrium steady-state system under steady heat conduction, the thermodynamic quantities from information theory are calculated and compared with those from the steady-state Boltzmann equation. We have found that information theory is inconsistent with the steady-state Boltzma

Jeong-Hyuck Park

We elaborate the idea that the matrix models equipped with the gauge symmetry provide a natural framework to describe identical particles. After demonstrating the general prescription, we study an exactly solvable harmonic oscillator type gauged matrix model. The model gives a generalization of the Calogero-Sutherland system where the strength of the inverse

J. C. Lopez Vieyra, A. V. Turbiner

The existence of the molecular ion $H_3^{++}$ in a magnetic field in a triangular configuration is revised. Variational method with an optimization of the form of the vector potential (gauge fixing) is used. It is shown that in the range of magnetic fields $10^8 < B < 10^{11} G$ the system $(pppe)$, with protons forming an equilateral triangle perpendicular

C. Altafini

In all the various proposals for quantum computers, a common feature is that the quantum circuits are expected to be made of cascades of unitary transformations acting on the quantum states. A framework is proposed to express these elementary quantum gates directly in terms of the control inputs entering into the continuous time forced Schrodinger equation.

Ulrich Mohrhoff

Quantum &#34;states&#34; are objective probability measures. Because their dependence on a time is not the time dependence of an evolving state, they are neither states of Nature nor &#34;states of knowledge.&#34; There is no such thing as an evolving state. This disposes of the problem posed by the apparent existence of two modes of evolution. What essentia

F. Marica, R. F. Snider

An exact expression for the cross polarization between two spin-1/2 particles is derived from the quantum Liouville equation. This is given in the form of two integrodifferential equations. These can be solved exactly in the static case (no sample spinning) and a powder average performed numerically. With magic angle spinning, the neglect of certain interfer

Paul E. Schupp

We show that all groups in a very large class of Coxeter groups are locally quasiconvex and have uniform membership problem solvable in quadratic time. If a group in the class satisfies a further hypothesis it is subgroup separable and relevant homomorphisms are also calculable in quadratic time. The algorithm also decides if a finitely generated subgroup ha

A. Vershik

The general class of the graded Lie algebras is defined. These algebras could be constructed using an arbitrary dynamical systems with discrete time and with invarinat measure. In this papers we consider the case of the central extension of Lie algebras which corresponds to the ordinary crossed product (as associative algebra) - series A. The structure of th

Krzysztof Burdzy

We present a new method for locating the nodal line of the second eigenfunction for the Neumann problem in a planar domain. The technique is based on the `mirror coupling&#39; of reflected Brownian motions.

Ilya Kapovich, Richard Weidmann

We show that for any positive integer $n$ there exists a constant $C(n)>0$ such that any $n$-generated group $G$, which acts by isometries on a $δ$-hyperbolic space (with $δ>0$), is either free or has a nontrivial element with translation length at most $δC(n)$.

Vladimir Dergachev

In this paper we explore a new method of analysis of associative algebras.

G. J. Chaitin

This article discusses what can be proved about the foundations of mathematics using the notions of algorithm and information. The first part is retrospective, and presents a beautiful antique, Godel&#39;s proof, the first modern incompleteness theorem, Turing&#39;s halting problem, and a piece of postmodern metamathematics, the halting probability Omega. Th

Volker Runde

Let $A$ be a Banach algebra. The flip on $A \otimes A^\op$ is defined through $A \otimes A^\op \ni a \tensor b \mapsto b \tensor a$. If $A$ is ultraprime, $\El(A)$, the algebra of all elementary operators on $A$, can be algebraically identified with $A \otimes A^\op$, so that the flip is well defined on $\El(\A)$. We show that the flip on $\El(A)$ is discont

V. N. Oraevsky, V. B. Semikoz, A. S. Volokitin

The spin effects on electromagnetic waves in a strongly magnetized plasma with rare collisions is considered with the help of relativistic kinetic equations, which takes into account the electron spin dynamics in the selfconsistent electric and magnetic fields. It is shown that for electromagnetic waves propagating almost perpendicular to ambient magnetic fi

Yu. S. Surovtsev, D. Krupa, M. Nagy

In a combined analysis of the experimental data on the coupled processes $ππ\toππ,K\bar{K}$ in the channel with $I^GJ^{PC}=0^+0^{++}$, the following results are obtained in a model-independent way: 1) The $f_0(665)$ state with properties of the $σ$-meson is proved to exist; 2) it is shown that the ${f_0}(980)$ and especially ${f_0}(1370)$ (if exists) have a

Da-Xin Zhang

A class of $|Δs|=1$ transition is analyzed in the $D_s^+-D^+$ and $\bar B_s^0-\bar B^0$ systems. Short distance Wilson coefficients are calculated within HQET. Novel features of the transitions are discussed. We find that these transitions are unobservable in the standard model.

Harleen Dahiya, Manmohan Gupta

Octet baryon magnetic moments are calculated within \chiQM, respecting color spin spin forces (Szczepaniak et al., PRL 87, 072001(2001)), incorporating the orbital angular momentum as well as the quark sea contribution through the Cheng and Li mechanism (PRL 80, 2789(1998)). Using configuration mixing generated by color spin spin forces as well as the concep

A. Bashir, A. Huet, A. Raya

We study three dimensional quenched Quantum Electrodynamics in the bare vertex approximation. We investigate the gauge dependence of the dynamically generated Euclidean mass of the fermion and the chiral condensate for a wide range of values of the covariant gauge parameter $ξ$. We find that (i) away from $ξ=0$, gauge dependence of the said quantities is con

Y. J. Zhang, B. S. Zou, L. M. Yang

This paper has been withdrawn by the authors. due fail of replacement of the paper. new version is hep-ph/0201214.

D. V. Bandurin, N. B. Skachkov

We study the effect of application of new set of cuts, proposed in our previous works, on the improvement of accuracy of the jet energy calibration with p p->photon+Jet+X process at Tevatron. Monte Carlo events produced by the PYTHIA 5.7 generator are used for this aim. The selection criteria for photon+Jet event samples that would provide a good balance of

Xavier Siemens, Ken D. Olum, Alexander Vilenkin

We present a method for the calculation of the gravitational back reaction cutoff on the smallest scales of cosmic string networks taking into account that not all modes on strings interact with all other modes. This results in a small scale structure cutoff that is sensitive to the initial spectrum of perturbations present on strings. From a simple model, w

Klaus Kroy, Gerd Sauermann, Hans J. Herrmann

We present a minimal model for the formation and migration of aeolian sand dunes. It combines a perturbative description of the turbulent wind velocity field above the dune with a continuum saltation model that allows for saturation transients in the sand flux. The latter are shown to provide the characteristic length scale. The model can explain the origin

A. Barone, T. Hakioglu, I. O. Kulik

We analyze the posibility of employing the mesoscopic-nanoscopic ring of a normal metal in a doubly degenerate persistent current state with a third auxihilary level and in the presence of the Aharonov-Bohm flux equal to the half of the normal flux quantum $\hbar c/e$ as a qubit. The auxiliary level can be effectively used for all fundamental quantum logic g

S. -R. Eric Yang, A. H. MacDonald

The maximum-density-droplet (MDD) state of quantum-dot electrons becomes unstable at strong magnetic fields to the addition of interior holes. Using exact diagonalization, we demonstrate that the first hole is located at the center of the dot when the number of electrons $N$ is smaller than $\sim 14$ and is located away from the center for larger dots. The s

Shan-Wen Tsai, D. L. Maslov, L. I. Glazman

Effects of the electron-electron interaction on tunneling into a metal in ultra-high magnetic field (ultra-quantum limit) are studied. The range of the interaction is found to have a decisive effect both on the nature of the field-induced instability of the ground state and on the properties of the system at energies above the corresponding gap. For a short-

Yohei Noda, Masatoshi Imada

Relationship among Wigner crystal, charge order and Mott insulator is studied by the path-integral renormalization group method for two-dimensional lattices with long-range Coulomb interaction. In contrast to Hartree-Fock results, the solid stability drastically increases with lattice commensurability. The transition to liquid occurs at the electron gas para

C. Motch, X. Barcons, F. Carrera, P. Guillout

The XMM-Newton Survey Science Center is currently conducting an optical identification programme of serendipitous EPIC sources at low galactic latitudes. The aim of this study is to quantify the various populations contributing to the overall X-ray emission of the Galaxy and elaborate identification rules that can be later applied to the bulk of the low gala

T. Tosaki, T. Hasegawa, Y. Shioya, N. Kuno

We present the results of high-resolution 13CO(1-0) mapping observations with the NRO 45m telescope of the area toward the southern bright arm region of M51, including the galactic center. The obtained map shows the central depression of the the circumnuclear ring and the spiral arm structure.The arm-to-interarm ratio of the 13CO(1-0) integrated intensity is

M. Bernardi, M. V. Alonso, L. N. da Costa, C. N. A. Willmer

In this paper R-band photometric and velocity dispersion measurements for a sample of 452 elliptical and S0 galaxies in 28 clusters are used to construct a template D_n-sigma relation. This template relation is constructed by combining the data from the 28 clusters, under the assumption that galaxies in different clusters have similar properties. The photome

M. Bernardi, M. V. Alonso, L. N. da Costa, C. N. A. Willmer

This paper presents data on the ENEARc subsample of the larger ENEAR survey of the nearby early-type galaxies. The ENEARc galaxies belong to clusters and were specifically chosen to be used for the construction of a D_n-sigma template. The ENEARc sample includes new measurements of spectroscopic and photometric parameters (redshift, velocity dispersion, line

N. Kaiser

The empirical value of the real part of the pion-deuteron scattering length can be well understood in terms of the dominant isovector $πN$-double scattering contribution. We calculate in chiral perturbation theory all one-pion loop corrections to this double scattering term which in the case of $πN$-scattering close the gap between the current-algebra predic

S. Yellin

Experimenters report an upper limit if the signal they are trying to detect is non-existent or below their experiment&#39;s sensitivity. Such experiments may be contaminated with a background too poorly understood to subtract. If the background is distributed differently in some parameter from the expected signal, it is possible to take advantage of this dif

M. Suzuki

If the vector glueball exists in the mass range that theory suggests, its resonance production cross section can be seen in e+e- annihilation only if the decay width is very narrow (< a few MeV). Otherwise it willbe observed only indirectly through its mixing with psi(2S). A few tests of the glueball-psi&#39; mixing are proposed for future charm factories.

Tsvi Piran, Shai Ayal

The realization that GRBs are narrowly beamed implied that the actual rate of GRBs is much larger than the observed one. There are 500 unobserved GRBs for each observed one. The lack of a clear trigger makes it hard to detect these unobserved GRBs as orphan afterglows. At late time, hundreds or thousands of years after a GRB, we expect to observe a GRB remna

Steven B. Giddings

High-energy scattering in non-conformal gauge theories is investigated using the AdS/CFT dual string/gravity theory. It is argued that strong-gravity processes, such as black hole formation, play an important role in the dual dynamics. Further information about this dynamics is found by performing a linearized analysis of gravity for a mass near an infrared

Herman J. Mosquera Cuesta, André Penna-Firme, Abdel Pérez-Lorenzana

In theories with an infinite extra dimension, free particles localized on the brane can leak out to the extra space. We argue that if there were color confinement in the bulk, electrons would be more able to escape than quarks and than protons (which are composed states). Thus, this process generates an electric charge asymmetry on brane matter densities. A

M. Doran, J. Jaeckel

The stability of scalar quintessence potentials under quantum fluctuations is investigated for both uncoupled models and models with a coupling to fermions. We find that uncoupled models are usually stable in the late universe. However, the coupling to fermions is severely restricted. We check whether a graviton induced fermion-quintessence coupling is compa

M. Porrati

In both old and recent literature, it has been argued that the celebrated van Dam-Veltman-Zakharov (vDVZ) discontinuity of massive gravity is an artifact due to linearization of the true equations of motion. In this letter, we investigate that claim. First, we exhibit an explicit -albeit somewhat arbitrary- fully covariant set of equations of motion that, up

H. Reinhardt, O. Schroeder, T. Tok, V. Ch. Zhukovsky

The zero modes of the Dirac operator in the background of center vortex gauge field configurations in $\R^2$ and $\R^4$ are examined. If the net flux in D=2 is larger than 1 we obtain normalizable zero modes which are mainly localized at the vortices. In D=4 quasi-normalizable zero modes exist for intersecting flat vortex sheets with the Pontryagin index equ

T. Eggeling, R. F. Werner

We present a general technique for hiding a classical bit in multipartite quantum states. The hidden bit, encoded in the choice of one of two possible density operators, cannot be recovered by local operations and classical communication without quantum communication. The scheme remains secure if quantum communication is allowed between certain partners, and

D. Challet, N. F. Johnson

We address the question of how to make best use of imperfect objects, such as defective analog and digital components. We show that perfect, or near-perfect, devices can be constructed by taking combinations of such defects. Any remaining objects can be recycled efficiently. In addition to its practical applications, our `defect combination problem&#39; prov

H. van Hees, J. Knoll

We investigate the symmetry properties for Baym&#39;s $Φ$-derivable schemes. We show that in general the solutions of the dynamical equations of motion, derived from approximations of the $Φ$-functional, do not fulfill the Ward-Takahashi identities of the symmetry of the underlying classical action, although the conservation laws for the expectation values o

Gary W. Gibbons, Daisuke Ida, Tetsuya Shiromizu

We prove the uniqueness theorem for asymptotically flat static vacuum black hole solutions in higher dimensional space-times. We also construct infinitely many non-asymptotically flat regular static black holes on the same spacetime manifold with the same spherical topology.

Francesco Miniati

We investigate numerically the contribution to the cosmic gamma-ray background from cosmic-rays ions and electrons accelerated at intergalactic shocks associated with cosmological structure formation. We show that the kinetic energy of accretion flows in the low-red-shift inter-galactic medium is thermalized primarily through moderately strong shocks, which

L. A. S. Machado, P. A. Maia Neto

We combine linear response theory and dimensional regularization in order to derive the dynamical Casimir force in the low frequency regime. We consider two parallel plates moving along the normal direction in $D-$dimensional space. We assume the free-space values for the mass of each plate to be known, and obtain finite, separation-dependent mass correction

T. A. Lozinskaya, V. V. Pravdikova, A. Finoguenov

We investigated the kinematics of ionized gas in an extended (20 degrees by 15 degrees) region containing the X-ray Superbubble in Cygnus with the aim of finding the shell swept up by a strong wind from Cyg OB2. H-alpha observations were carried out with high angular and spectral resolutions using a Fabry-Perot interferometer attached to the 125-cm telescope

Jesper Dall, Michael Christensen

We analyse graphs in which each vertex is assigned random coordinates in a geometric space of arbitrary dimensionality and only edges between adjacent points are present. The critical connectivity is found numerically by examining the size of the largest cluster. We derive an analytical expression for the cluster coefficient which shows that the graphs are d

Hongwei Xiong, Shujuan Liu, Guoxiang Huang, Zhijun Xu

We investigate the evolution process of the interference pattern for a coherent array of Bose-Einstein condensates in a magnetic trap after the optical lattices are switched off. It is shown that there is a decay and revival of the density oscillation for the condensates confined in the magnetic trap. We find that, due to the confinement of the magnetic trap

E. A. Choban, G. A. Kazakov

A possibility of a verification of CPT-invariance of QED for bound states by example of muonium or antimuonium produced in reactions of scattering of electrons or positrons by nuclei is considered. The number of events of the muonium production is estimated for contemporary accelerators. The method of the detection of muonium by measuring of oscillations of

J. Cserti, A. Kormányos, Z. Kaufmann, J. Koltai

We examine the density of states of an Andreev billiard and show that any billiard with a finite upper cut-off in the path length distribution $P(s)$ will possess an energy gap on the scale of the Thouless energy. An exact quantum mechanical calculation for different Andreev billiards gives good agreement with the semi-classical predictions when the energy d

R. Benton Metcalf

When a gravitational lens produces two or more images of a quasar&#39;s radio jet the images can be compared to reveal the presence of small structures along one or more of the lines of sight. If mass is distributed smoothly on scales of <~ 10^7 Msun independent bends in the jet images on milli-arcsecond scales will not be produced. All three of the well col

Alexander Zhalij

We classify (1+3)-dimensional Pauli equations for a spin-1/2 particle interacting with the electro-magnetic field, that are solvable by the method of separation of variables. As a result, we obtain the eleven classes of vector-potentials of the electro-magnetic field A(t,x) providing separability of the corresponding Pauli equations. It is established, in pa

D. Andrienko, M. P. Allen, G. Skacej, S. Zumer

Combining molecular dynamics and Monte Carlo simulation we study defect structures around an elongated colloidal particle embedded in a nematic liquid crystal host. By studying nematic ordering near the particle and the disclination core region we are able to examine the defect core structure and the difference between two simulation techniques. In addition,

L. Stodolsky

We indicate some of the lessons learned from our work on coherence and decoherence in various fields and mention some recent work with sold state devices as elements of the ``quantum computer&#39;&#39;, including the realization of simple logic gates controlled by adiabatic processes. We correct a commonly held misconception concerning decoherence for a free

D. Andrienko, M. P. Allen

Combining molecular simulation, Onsager theory and the elastic description of nematic liquid crystals, we study the dependence of the nematic liquid crystal elastic constants and the zenithal surface anchoring coefficient on the value of the bulk order parameter.

A. V. Nikolaev, P. N. Dyachkov

We formulate a Hartree-Fock-LAPW method for electronic band structure calculations. The method is based on the Hartree-Fock-Roothaan approach for solids with extended electron states and closed core shells where the basis functions of itinerant electrons are linear augmented plane waves. All interactions within the restricted Hartree-Fock approach are analyz

Yoshiharu Kawamura

We propose a generalization of Heisenbergs&#39; matrix mechanics based on many-index objects. It is shown that there exists a solution describing a harmonic oscillator and many-index objects lead to a generalization of spin algebra.

Zhenjun Xiao, Minping Zhang

In this paper we try to extract the CKM angle $γ$ from the new &#34;mixed&#34; system of $B^+ \to π^+ K^0$ and $B_d^0 \to π^0 K^0$ decays. We also made an update for the constraints on the angle $γ$ from the observables $R$ and $A_0$. In the parametrization, the SU(2) isospin symmetry of strong interactions has been applied. We found the following results: (