January 2002 arXiv papers — page 9

Hao Chen

We introduce algebriac sets in the products of complex projective spaces for multipartite mixed states, which are independent of their eigenvalues and only measure the "position" of their eigenvectors, as their non-local invariants (ie. remaining invariant after local untary transformations). These invariants are naturally arised from the physical co

Matthias Clausen, Ron MacKenzie, Robert Sass, Kenneth Underwood

All Control Systems that grow to any size have a variety of data that are stored in different formats on different nodes in the network. Examples include sensor value and status, archived sensor data, device oriented support data and relationships, message logs, application and machine configurations etc. Each type of data typically has a different programmi

Daniel M. Zuckerman, Thomas B. Woolf

Systematic inaccuracy is inherent in any computational estimate of a non-linear average, due to the availability of only a finite number of data values, N. Free energy differences (DF) between two states or systems are critically important examples of such averages in physical, chemical and biological settings. Previous work has demonstrated, empirically, th

B. Ananthanarayan, J. Meeraa, Bharti Sharma, Seema Sharma

This two-part article considers certain fundamental symmetries of nature, namely the discrete symmetries of parity (P), charge conjugation (C) and time reversal (T), and their possible violation. Recent experimental results are discussed in some depth. In this second part, we discussion CP and $T$ violation and arrive at a synthesis.

B. Ananthanarayan, J. Meeraa, Bharti Sharma, Seema Sharma

This two-part article considers certain fundamental symmetries of nature, namely the discrete symmetries of parity (P), charge conjugation (C) and time reversal (T), and their possible violation. Recent experimental results are discussed in some depth. In the first part of this article we present a general background and discuss parity violation.

E. Epelbaum, A. Nogga, W. Gloeckle, H. Kamada

Nucleon-nucleon (NN) forces from chiral perturbation theory at next-to-leading (NLO) and next-to-next-to-leading order (NNLO) are applied to systems with two, three and four nucleons. At NNLO, we consider two versions of the chiral potential which differ in the strength of the two-pion-exchange (TPE) but describe two nucleon observables equally well. The NNL

F. Gastineau, J. Aichelin

Using an extended version of the Nambu-Jona-Lasinio model we build a simple description of the baryons as diquark-quark bound states. First, a description of the diquarks in a dense and hot medium is presented. Then, we introduce the formalism for the baryons based on the Faddeev equation associated with the so-called `` static approximation'' which

J. Barea, C. E. Alonso, J. M. Arias

The boson-conserving one-nucleon transfer operator in the interacting boson model (IBA) is reanalyzed. Extra terms are added to the usual form used for that operator. These new terms change generalized seniority by one unit, as the ones considered up to now. The results obtained using the new form for the transfer operator are compared with those obtained wi

C. A. Bertulani

Giant resonances and giant resonances built on other giant resonances in nuclei are observed with very large cross sections in relativistic heavy ion collisions. A theoretical effort is underway to understand the reaction mechanism which leads to this process, as well as a better understanding of the microscopic properties of multiphonon states, e.g., their

P. Moskal, H. -H. Adam, A. Budzanowski, R. Czyzykiewicz

The production of K+ and K- mesons in elementary proton-proton collision has been investigated at the Cooler Synchrotron COSY in Juelich. A high quality proton beam with low emittance and small momentum spread permitted to study the creation of these mesons very close to the kinematical threshold. The energy dependence of the total cross section is investiga

Paul B. Slater

We accept the implicit challenge of A. Uhlmann in his 1994 paper, "Parallel Lifts and Holonomy along Density Operators: Computable Examples Using O(3)-Orbits," by, in fact, computing the holonomy invariants for rotations of certain n-level Gibbsian density matrices (n = 2,...,11). From these, we derive, by the tracing operation, the associated geomet

Eugene Lerman

These are notes for a course on contact manifolds and torus actions delivered at the summer school on Symplectic Geometry of Integrable Hamiltonian Systems at Centre de Recerca Matemàtica in Barcelona in July 2001. To be published by Birkhauser.

Masa-Hiko Saito, Hitomi Terajima

In this paper, we study Riccati solutions of Painlevé equations from a view point of geometry of Okamoto-Painlevé pairs $(S,Y)$. After establishing the correspondence between (rational) nodal curves on $S-Y$ and Riccati solutions, we give the complete classification of the configurations of nodal curves on $S-Y$ for each Okamoto-Painlevé pair $(S, Y)$. As an

O. I. Mokhov

We solve the problem of description for nonsingular pairs of compatible flat metrics in the general N-component case. The integrable nonlinear partial differential equations describing all nonsingular pairs of compatible flat metrics (or, in other words, nonsingular flat pencils of metrics) are found and integrated. The integrating of these equations is base

O. I. Mokhov

We solve the problem of reducing to the simplest and convenient for our purposes, canonical form for an arbitrary pair of compatible nonlocal Poisson brackets of hydrodynamic type generated by metrics of constant Riemannian curvature in order to get an effective construction of the integrable hierarchies related to all these compatible Poisson brackets.

Antonio J. B. Lopes-Pinto, Diana Aldea Mendes

Let $X,Y$ be topological vector spaces or metric spaces, and let {$f:X\times Y \to \Re $} be a real function lower semicontinuous in the first variable and upper semicontinuous in the second one. It is proved that $f$ is globally measurable. Sierpinski (1925) has been raised this question in the case $X=Y=\Re $. This particular case was solved by Kempisty (1

Sema Salur

The purpose of this paper is to give an application of the gluing theorem for special Lagrangian submanifolds of a Calabi-Yau 3-fold. We proved a gluing theorem before to smooth a codimension-two singularity of a particular special Lagrangian submanifold. In this paper we will show that this theorem can be applied to more general cases where different specia

Charles P. Boyer, Krzysztof Galicki, Michael Nakamaye

We discuss the Sasakian geometry of odd dimensional homotopy spheres. In particular, we give a completely new proof of the existence of metrics of positive Ricci curvature on exotic spheres that can be realized as the boundary of a parallelizable manifold. Furthermore, it is shown that on such homotopy spheres $\scriptstyle{Σ^{2n+1}}$ the moduli space of Sas

Eugene Lerman

We complete the classification of compact connected contact toric manifolds initiated by Banyaga and Molino and by Galicki and Boyer. As an application we prove the conjectures of Toth and Zelditch on toric integrable systems on the n-torus and the 2-sphere.

Arundhati Dasgupta, Hermann Nicolai, Jan Plefka

We review aspects of quantisation of the 11-dimensional supermembrane world volume theory. We explicitly construct vertex operators for the massless states and study interactions of supermembranes. The open supermembrane and its vertex operators are discussed. We show how our results have direct applications to Matrix theory by appropriate regularisation of

A. D'Adda, P. Provero

Branched n-coverings of Riemann surfaces are described by a 2d lattice gauge theory of the symmetric group S(n) defined on a cell discretization of the surface. We study the theory in the large-n limit, and we find a rich phase diagram with first and second order transition lines. The various phases are characterized by different connectivity properties of t

Y. M. Cho

Based on the gauge independent decomposition of the non-Abelian gauge field into the dual potential and the valence potential, we calculate the one loop effective action of SU(2) QCD in an arbitrary constant monopole background, using the background field method. Our result provides a strong evidence for a dynamical symmetry breaking through the monopole con

Thomas G. Rizzo

We examine the rates for the production of black holes(BH) at the LHC in light of the exponential suppression of the geometric cross section estimate recently proposed by Voloshin. We show that the resulting production rates will still be quite large over a reasonably wide range of model parameters. While BH production may no longer be the dominant collider

U. Baur, R. Brock, J. Parsons, M. Albrow

We discuss the physics opportunities and detector challenges at future hadron colliders. As guidelines for energies and luminosities we use the proposed luminosity and/or energy upgrade of the LHC (SLHC), and the Fermilab design of a Very Large Hadron Collider (VLHC). We illustrate the physics capabilities of future hadron colliders for a variety of new phys

Ernest Ma

In view of the recently reported evidence for a nonzero Majorana mass of the electron neutrino, together with the established phenomena of atmospheric and solar neutrino oscillations, the case of three nearly mass-degenerate Majorana neutrinos is now a distinct possibility. I show in this paper how a natural pattern of symmetry breaking in the recently propo

H. V. Klapdor-Kleingrothaus, U. Sarkar

Recently a positive indication of the neutrinoless double beta decay has been announced. We study the implications of this result taking into consideration earlier results on atmospheric neutrinos and solar neutrinos. We also include in our discussions the recent results from SNO and K2K. We point out that on the confidence level given for the double beta si

G. S. Sharov

For the relativistic string with massive ends the small disturbances of its rotational motion (quasirotational states) are investigated. They are presented in the form of Fourier series with the two types of oscillatory modes. They have the form of stationary waves correspondently in the rotational plane and in the orthogonal direction. The calculated values

Marc Sher, Shuquan Nie

In many models of CP violation, the electric dipole moment (EDM) of a heavy charged or neutral lepton could be very large. We present an explicit model in which a heavy neutrino EDM can be as large as $10^{-16}$ e-cm, or even a factor of ten larger if fine-tuning is allowed, and use an effective field theory argument to show that this result is fairly robust

F. Boudjema, A. Semenov

We address the issue of the reconstruction of the scalar potential of a two-Higgs doublet model having in mind that of the MSSM. We first consider the general CP conserving dim-4 effective potential. To fully reconstruct this potential, we show that even if all the Higgs masses and their couplings to the standard model particles are measured one needs not on

D. Ebert, R. N. Faustov, V. O. Galkin, A. P. Martynenko

Mass spectra of baryons consisting of two heavy (b or c) and one light quarks are calculated in the framework of the relativistic quark model. The light quark-heavy diquark structure of the baryon is assumed. Under this assumption the ground and excited states of both the diquark and quark-diquark bound system are considered. The quark-diquark potential is c

Yong-Jun Zhang, Bing-Song Zou, Li-Ming Yang

Taking proton as an ensemble of quark-gluon Fock states and using the principle of detailed balance, we construct a simple statistical model for parton distribution of proton. The recent observed Bjorken-$x$ dependent light flavor sea quark asymmetry $\bar{d}(x)-\bar{u}(x)$ can be well reproduced by Monte Carlo simulation as a pure statistical effect.

Yong-Jun Zhang, Bo-Qiang Ma, Li-Ming Yang

In this study, the proton is taken as an ensemble of quark-gluon Fock states. Using the principle of detailed balance, we find $\bar{d}-\bar{u} \approx 0.124$, which is in surprisingly agreement with the experimental observation.

John N. Bahcall, V. Barger, Danny Marfatia

We show that the combined data from solar neutrino experiments and from the KamLAND reactor neutrino experiment can establish an upper limit on, or detect, potential CPT violation in the neutrino sector of order 10^{-20} GeV to 10^{-21} GeV.

G. Corcella, I. G. Knowles, G. Marchesini, S. Moretti

A new release of the Monte Carlo program HERWIG (version 6.4) is now available. The main new features are: spin correlations between the production and decay of heavy fermions, i.e. top quarks, tau leptons and SUSY particles; polarization effects in SUSY production processes in lepton-lepton collisions; an interface to TAUOLA for tau decays; MSSM Higgs proce

Yu-Ping Kuang

We briefly review the recent developments of probing the electroweak symmetry breaking mechanism at high energy colliders such as the CERN LEP2, the Fermilab Tevatron, the CERN LHC and the e(+)e(-) linear colliders. Both weakly interacting and strongly interacting electroweak symmetry breaking mechanisms are concerned.

Yu-Ping Kuang

We sketch some of our recent studies on probing strongly interacting electroweak symmetry breaking mechanism at high energy colliders such as the CERN LHC and the future e(+)e(-) linear collider. The study includes both model-dependent and model-independent probes.

V. Mandic, A. T. Pierce, P. Gondolo, H. Murayama

We examine if there is a lower bound on the direct detection cross section for the neutralino dark matter in the MSSM. If we impose the minimal supergravity boundary conditions as well as the &#34;naturalness&#34; condition, in particular m_{1/2} < 300 GeV, we show that there is a lower bound of 10^{-46}cm^2 on the cross section for neutralino scattering off

Uta Stosslein

Recent progress in the field of spin physics of high energy particle interactions is reviewed with particular emphasis on the spin structure functions as measured in polarized deep inelastic lepton-nucleon scattering (DIS). New measurements are presented to obtain more direct information on the composition of the nucleon angular momentum, with results from s

D. Fayolle

In its second phase, LEP has allowed to study four fermion processes never observed before. Results are presented on the charged triple gauge boson couplings (TGC) from the W-pair, Single W and Single gamma production. The anomalous quartic gauge couplings (QGC) are constrained using production of WWgamma, nunubargammagamma and Zgammagamma final states. Fina

Marc Mars

We present a new non-diagonal G2 inhomogeneous perfect-fluid solution with barotropic equation of state p=rho and positive density everywhere. It satisfies the global hyperbolicity condition and has no curvature singularity anywhere. This solution is very simple in form and has two arbitrary constants.

O. Khovanskaya

The stability under small time perturbations of the dilatonic black hole solution near the determinant curvature singularity is proved. This fact gives the additional arguments that the investigated topological configuration can realise in nature. In the frames of this model primordial black hole remnants are examined as time stable objects, which can form a

Philippe Jehiel, Dov Samet

A valuation for a player in a game in extensive form is an assignment of numeric values to the players moves. The valuation reflects the desirability moves. We assume a myopic player, who chooses a move with the highest valuation. Valuations can also be revised, and hopefully improved, after each play of the game. Here, a very simple valuation revision is co

Churn-Jung Liau

This paper is aimed at providing a uniform framework for reasoning about beliefs of multiple agents and their fusion. In the first part of the paper, we develop logics for reasoning about cautiously merged beliefs of agents with different degrees of reliability. The logics are obtained by combining the multi-agent epistemic logic and multi-sources reasoning

Philip W. Anderson

In recent years a fashion has grown up to ascribe great importance to ``quantum critical points&#39;&#39; at T=0, at the boundary between the basins of attraction to the stable fixed points of ordered ground states. I argue that more physical significance in connecting microscopic interactions with observed phenomena lies in the common phenomenon of partiall

Jonathan P. K. Doye

Here we analyze the topology of the network formed by the minima and transition states on the potential energy landscape of small clusters. We find that this network has both a small-world and scale-free character. In contrast to other scale-free networks, where the topology results from the dynamics of the network growth, the potential energy landscape is a

Philip W. Anderson

I discuss various direct calculations of the properties of the one-band Hubbard model on a square lattice and conclude that these properties sufficiently resemble those of the cuprate superconductors that no more complicated interactions are necessary to cause high Tc superconductivity.. In particular, I discuss phonon effects and conclude that these may be

Th. Proffen, V. Petkov, S. J. L. Billinge, T. Vogt

Many crystalline materials show chemical short range order and relaxation of neighboring atoms. Local structural information can be obtained by analyzing the atomic pair distribution function (PDF) obtained from powder diffraction data. In this paper, we present the successful extraction of chemical short range order parameters from the x-ray PDF of a quench

Steven T. Bramwell, Michel J. -P. Gingras

A frustrated system is one whose symmetry precludes the possibility that every pairwise interaction (``bond&#39;&#39;) in the system can be satisfied at the same time. Such systems are common in all areas of physical and biological science. In the most extreme cases they can have a disordered ground state with ``macroscopic&#39;&#39; degeneracy, that is, one

Anil Gannepalli, Surya K. Mallapragada

Atomistic studies are carried out to investigate the formation and evolution of defects during nanoindentation of a gold crystal. The results in this theoretical study complement the experimental investigations [J. D. Kiely and J. E. Houston, Phys. Rev. B, v57, 12588 (1998)] extremely well. The defects are produced by a three step mechanism involving nucleat

Z. G. Yu, M. E. Flatte

We derive a drift-diffusion equation for spin polarization in semiconductors by consistently taking into account electric-field effects and nondegenerate electron statistics. We identify a high-field diffusive regime which has no analogue in metals. In this regime there are two distinct spin diffusion lengths. Furthermore, spin injection from a ferromagnetic

D. F. Agterberg, Matthew J. W. Dodgson

For multi-component superconductors, it is known that the presence of symmetry breaking fields can lead to multiple superconducting phase transitions. This phenomenon is best illustrated in UPt$_3$. Motivated by recent small angle neutron scattering experiments on the vortex state of UPt$_3$, the London theory in the vicinity of such phase transitions is det

Wen Dong, Dong-Lai Yao, Yin-Zhong Wu, Zhen-Ya Li

Long-range effects on the pyroelectric coefficient of a ferroelectric superlattice consisting of two different ferroelectric materials are investigated based on the Transverse Ising Model. The effects of the interfacial coupling and the thickness of one period on the pyroelectric coefficient of the ferroelectric superlattice are studied by taking into accoun

Stefano Mossa, Marc Barthelemy, H. Eugene Stanley, Luis A. Nunes Amaral

We formulate a general model for the growth of scale-free networks under filtering information conditions--that is, when the nodes can process information about only a subset of the existing nodes in the network. We find that the distribution of the number of incoming links to a node follows a universal scaling form, i.e., that it decays as a power law with

M. V. Mostovoy, D. I. Khomskii

We consider the superexchange in `frustrated&#39; Jahn-Teller systems, such as the transition metal oxides NaNiO_2, LiNiO_2, and ZnMn_2O_4, in which transition metal ions with doubly degenerate orbitals form a triangular or pyrochlore lattice and are connected by the 90-degree metal-oxygen-metal bonds. We show that this interaction is much different from a m

Mario Jose de Oliveira, Alberto Petri

We investigate the quenching process in lattice systems with short range interaction and several crystalline states as ground states. We consider in particular the following systems on square lattice: - hard particle (exclusion) model; - q states planar Potts model. The system is initially in a homogeneous disordered phase and relaxes toward a new equilibriu

S. Fabris, S. Nufer, C. Elsaesser

The microscopic structure of a prismatic $Σ3$ $(10\bar{1}0)$ twin boundary in \aal2o3 is characterized theoretically by ab-initio local-density-functional theory, and experimentally by spatial-resolution electron energy-loss spectroscopy in a scanning transmission electron microscope (STEM), measuring energy-loss near-edge structures (ELNES) of the oxygen $K

M. R. Norman, C. Pepin

Using a simple model for the frequency dependent scattering rate, we evaluate the in-plane optical integral for cuprate superconductors in the normal and superconducting states. In the overdoped region, this integral is conserved. In the optimal and underdoped region, though, the optical integrals differ, implying a lowering of the in-plane kinetic energy in

S. De Palo F. Rapisarda Gaetano Senatore

Using Diffusion Monte Carlo simulations we have investigated the ground state of a symmetric electron-hole bilayer and determined its phase diagram at T=0. We find clear evidence of an excitonic condensate, whose stability however is affected by in-layer electronic correlation. This stabilizes the electron-hole plasma at large values of the density or inter-

A. A. Ovchinnikov

It has been shown that under joint action of DC magnetic and AC electric fields neutral particles (atoms,molecules,nano-size particles etc.) nearby interface move with permanent velocity along the surface. The driving force depends on non-linear dynamical properties of polarization of the particles and a coupling between the polarisation and the position of

V. Charbois, V. V. Naletov, J. Ben Youssef, O. Klein

The ferromagnetic resonance spectrum of a normally magnetized YIG disk, with thickness of 4.75$μ$m and radius of 80$μ$m, is measured at room temperature both by magnetic resonance force microscopy and by standard detection of the microwave susceptibility. The comparison indicates that MRFM represents one of the most potent means of obtaining the \emph{comple

A. E. Allahverdyan, Th. M. Nieuwenhuizen

The spin-boson model, often used in NMR and ESR physics, quantum optics and spintronics, is considered in a solvable limit to model a spin one-half particle interacting with a bosonic thermal bath. By applying external pulses to a non-equilibrium initial state of the spin, work can be extracted from the thermalized bath. It occurs on the timescale $\T_2$ inh

Rong Lu, Hui Pan, Jia-Lin Zhu, Bing-Lin Gu

The tunneling of a giant spin at excited levels is studied theoretically in mesoscopic magnets with a magnetic field at an arbitrary angle in the easy plane. Different structures of the tunneling barriers can be generated by the magnetocrystalline anisotropy, the magnitude and the orientation of the field. By calculating the nonvacuum instanton solution expl

Subir Sachdev, Shou-Cheng Zhang

This article presents our perspective on STM measurements by Hoffman et al. (cond-mat/0201348) of the vortex lattice in BSCCO. We discuss implications of these measurements for various theories of the cuprate superconductors.

Simon P. Driver

Here we present a pilot study into whether elliptical galaxy counts alone, can place a useful constraint on the Omega_M - Omega_Lambda-plane. The elliptical galaxy counts are drawn from three surveys: The Millennium Galaxy Catalogue (16 > B_KPNO > 20), the B-band Parallel Survey (20 > B_AB >24) and the Hubble Deep Fields (23 > B_AB > 28). The elliptical lumi

Laird M. Close, Nick Siegler, Dan Potter, Wolfgang Brandner

Use of the highly sensitive Hokupa&#39;a/Gemini curvature wavefront sensor has allowed for the first time direct adaptive optics (AO) guiding on M8-M9 very low mass (VLM) stars. An initial survey of 20 such objects (SpT=M8-M9) discovered 4 binaries. Three of the systems have separations of less than 4.2 AU and similar mass ratios (Delta K<0.8 mag; 0.85<q<1.0

R. J. Reynolds, L. M. Haffner, G. J. Madsen

The Wisconsin H-Alpha Mapper (WHAM) is a high throughput Fabry-Perot facility developed specifically to detect and explore the warm, ionized component of the interstellar medium at high spectral resolution. It began operating at Kitt Peak, Arizona in 1997 and has recently completed the WHAM Northern Sky Survey (WHAM-NSS), providing the first global view of t

C. Tadhunter, R. Dickson, R. Morganti, T. G. Robinson

We present spectroscopic and polarimetric observations of a complete, optically unbiased sample of 2Jy radio galaxies at intermediate redshifts (0.15 < z < 0.7). These data -- which cover the nuclear regions of the target galaxies -- allow us to quantify for the first time the various components that contribute to the UV excess in the population of powerful,

Reba M. Bandyopadhyay, Philip A. Charles, Tariq Shahbaz, R. Mark Wagner

We present infrared photometry of the Galactic Bulge X-ray binary systems GX13+1 and GX17+2 obtained in 1997 July and August using OSIRIS on the 1.8m Perkins Telescope at Lowell Observatory. GX13+1 clearly varies over ~0.6 magnitudes in the K-band. Our light curve suggests a modulation on a timescale of ~20 days, which is in agreement with previously propose

Javier Trujillo-Bueno, Roberto Casini, Marco Landolfi, Egidio Landi Degl&#39;Innocenti

We demonstrate that the atomic alignment of the hyperfine-structure components of the ground level S$_{1/2}$ of Na {\sc i} and of the upper level P$_{1/2}$ of the D$_1$ line are practically negligible for magnetic strengths $B>10 \rm G$, and virtually zero for $B\ga 100 \rm G$. This occurs independently of the magnetic-field inclination on the stellar surfac

Attila Grandpierre

In a Dynamic Solar Model (DSM) the temperature dependences of the pp cycle neutrinos will be different from the ones determined by solar model calculations with the luminosity constraint. Instead of the usual neutrino fluxes pp ~ T^{-1/2}, Be ~ T^8, B ~ T^{18}, we determined by the nuclear reaction rates formulas pp ~ T^{4.2}, Be ~ T^{-1/2}, B ~ T^{13.5}, fo

M. Salaris, S. Cassisi, A. Weiss

Theoretical predictions of Red Giant Branch stars&#39; effective temperatures, colors, luminosities and surface chemical abundances are a necessary tool for the astrophysical interpretation of the visible--near infrared integrated light from unresolved stellar populations, the Color-Magnitude-Diagrams of resolved stellar clusters and galaxies, and spectrosco

A. C. Fabian

The gas temperature in the cores of many clusters of galaxies drops inward by about a factor of three or more within the central 100kpc radius. The radiative cooling time drops over the same region from 5 or more Gyr down to about 10^8 yr. Although it would seem that cooling has taken place, XMM and Chandra spectra show no evidence for strong mass cooling ra

F. Camilo, R. N. Manchester, B. M. Gaensler, D. R. Lorimer

We report the discovery with the Parkes radio telescope of a pulsar associated with the ~ 1700 yr-old oxygen-rich composite supernova remnant G292.0+1.8. PSR J1124-5916 has period 135 ms and period derivative 7.4e-13, implying characteristic age 2900 yr, spin-down luminosity 1.2e37 erg/s, and surface magnetic field strength 1.0e13 G. Association between the

Michael A. Nowak, Joern Wilms, James B. Dove

We present spectral fits and timing analysis of Rossi X-ray Timing Explorer observations of GX339-4. These observations were carried out over a span of more than two years and encompassed both the soft/high and hard/low states. Hysteresis in the soft state/hard state transition is observed. The hard state exhibits a possible anti-correlation between coronal

Adam J. Burgasser, James Liebert, J. Davy Kirkpatrick, John E. Gizis

We present spectroscopic and imaging observations of the active T dwarf 2MASS 1237+6526, intended to investigate the emission mechanism of this cool brown dwarf. The H$α$ emission line first detected in 1999 July appears to be persistent over 1.6 years, with no significant variation from $\log_{10}(L_{Hα}$/L$_{bol}$) = $-$4.3, ruling out flaring as a possibl

Allan Sandage, A. Saha

Please note that this abstract has been shortened from that found in the paper. A brief history is given of the development of the correction for observation selection bias inherent in the calibration of absolute magnitudes using trigonometric parallaxes. As a tutorial to gain an intuitive understanding of several complicated trigonometric bias problems, we

P. R. Wozniak, A. Udalski, M. Szymanski, M. Kubiak

We present the first edition of a catalog of variable stars from OGLE-II Galactic Bulge data covering 3 years: 1997-1999. Typically 200-300 I band data points are available in 49 fields between -11 and 11 degrees in galactic longitude, totaling roughly 11 square degrees in sky coverage. Photometry was obtained using the Difference Image Analysis (DIA) softwa

Clifford Henry Taubes

This article explains how to construct immersed Lagrangian submanifolds in C^2 that are asymptotic at large distance from the origin to a given braid in the 3-sphere. The self-intersections of the Lagrangians are related to the crossings of the braid. These Lagrangians are then used to construct immersed Lagrangians in the vector bundle O(-1) oplus O(-1) ove

Wynn C. G. Ho, Dong Lai

We study the effect of vacuum polarization on the atmosphere structure and radiation spectra of neutron stars with surface magnetic fields B=10^14-10^15 G, as appropriate for magnetars. Vacuum polarization modifies the dielectric property of the medium and gives rise to a resonance feature in the opacity; this feature is narrow and occurs at a photon energy

J. D. Silverman, P. J. Green, D. W. Kim, B. J. Wilkes

We present X-ray and optical observations of CXOMP J213945.0-234655, a high redshift (z=4.93) quasar discovered through the Chandra Multiwavelength Project (ChaMP). This object is the most distant X-ray selected quasar published, with an X-ray luminosity of L(X)=5.9x10^44 erg/s (measured in the 0.3-2.5 keV band and corrected for Galactic absorption). CXOMP J

Yu-Ping Kuang

The psi(1P1) state can be produced at the Beijing Electron-Positron Collider (BEPC) in the process psi&#39;-->psi(1P1)+pi(0). We calculate the rate of this process taking account of the S-D mixing effect in psi&#39;. It is shown that the rate is about a factor of 3 smaller than the simple result without considering the S-D mixing effect. Possible detecting c

A. A. Burkov, A. H. MacDonald

We report on a theoretical study of $ν=2$ bilayer quantum Hall systems with a magnetic field that has a component parallel to the layers. As in the $ν=1$ case, interlayer phase coherence is closely coupled to electron correlations and the Aharonov-Bohm phases introduced by a parallel magnetic field can have a strong influence on the ground state of the syste

R. van Zon, H. van Beijeren

A kinetic approach is adopted to describe the exponential growth of a small deviation of the initial phase space point, measured by the largest Lyapunov exponent, for a dilute system of hard disks, both in equilibrium and in a uniform shear flow. We derive a generalized Boltzmann equation for an extended one-particle distribution that includes deviations fro

David Merritt, Milos Milosavljevic, Licia Verde, Raul Jimenez

The annihilation rate of weakly interacting cold dark matter particles at the galactic center could be greatly enhanced by the growth of a density spike around the central supermassive black hole (SBH). Here we discuss the effects of hierarchical mergers on the central spike. Mergers between halos containing SBHs lead to the formation of SBH binaries which t

B. N. Narozhny, Gábor Zala, I. L. Aleiner

We calculate the temperature dependence of the weak localization correction in a two dimensional system at arbitrary relation between temperature, $T$ and the elastic mean free time. We describe the crossover in the dephasing time ${τ_ϕ(T)}$ between the high temperature, $1/τ_ϕ\simeq T^2 \ln T$, and the low temperature $1/τ_ϕ\simeq T$ behaviors. The prefacto

Pengjie Zhang, Ue-Li Pen, Benjamin Wang

The Sunyaev Zel'dovich effect (SZ effect) is a complete probe of ionized baryons, the majority of which are likely hiding in the intergalactic medium. We ran a $512^3$ $\Lambda$CDM simulation using a moving mesh hydro code to compute the statistics of the thermal and kinetic SZ effect such as the power spectra and measures of non-Gaussianity. The thermal SZ

Yasuaki Hikida

The orientifolds of SU(2)/U(1) gauged WZW models are investigated. In particular, we construct the new type orientifolds and identify their geometries. We closely follow the analysis of D-branes in the SU(2)/U(1) WZW models, which was given by Maldacena, Moore and Seiberg.

Anne M Green, Anupam Mazumdar

In low scale quantum gravity scenarios the fundamental scale of nature can be as low as TeV, in order to address the naturalness of the electroweak scale. A number of difficulties arise in constructing specific models; stabilisation of the radius of the extra dimensions, avoidance of overproduction of Kaluza Klein modes, achieving successful baryogenesis and

Maurice Goldhaber

Although there have been many experimental and theoretical efforts to measure and interpret small deviations from the standard model of particle physics, the gap that the model leaves in understanding why there are only three generations of elementary fermions, with hierarchical masses, has not received the attention it deserves. I present here an attempt to

Karl Gerd H. Vollbrecht, Michael M. Wolf

We show that bipartite quantum states of any dimension, which do not have a positive partial transpose, become 1-distillable when one adds an infinitesimal amount of bound entanglement. To this end we investigate the activation properties of a new class of symmetric bound entangled states of full rank. It is shown that in this set there exist universal activ

Edi Halyo

Asymptotically de Sitter spaces can be described by Euclidean boundary theories with entropies given by the modified Cardy--Verlinde formula. We show that the Cardy--Verlinde formula describes a string with a rescaled tension which in fact is a string at the stretched cosmological horizon as seen from the boundary. The temperature of the boundary theory is t

Robert V. Harlander, William B. Kilgore

The Higgs boson production cross section at pp and p\bar{p} colliders is calculated in QCD at next-to-next-to-leading order (NNLO). We find that the perturbative expansion of the production cross section is well behaved and that scale dependence is reduced relative to the NLO result. These findings give us confidence in the reliability of the prediction. We

N. R. Claussen, E. A. Donley, S. T. Thompson, C. E. Wieman

An initially stable 85Rb Bose-Einstein condensate (BEC) was subjected to a carefully controlled magnetic field pulse in the vicinity of a Feshbach resonance. This pulse probed the strongly interacting regime for the condensate, with calculated values for the diluteness parameter (na^3) ranging from 0.01 to 0.5. The field pulse was observed to cause loss of a

P. Kinsler, W. Th. Wenckebach

It should be possible to improve hot-hole laser performance by moving from bulk materials to a quantum well structure. The extra design parameters enable us to alter the band structure by changing the crystal orientation of the growth direction; to use the well width to shift the subband offsets, enabling the effect of the LO phonon scattering cut-off to be

C. Forssen, V. D. Efros, M. V. Zhukov

An analytical model, recently developed to study the electromagnetic dissociation (EMD) energy spectra of two-neutron halo nuclei, is applied to 11-Li and 14-Be. We find that a reliable set of experimental data on EMD could help to resolve the problem concerning the structure of the 11-Li ground state. For 14-Be we find a mutual inconsistency between the exi

N. R. Ikhsanov, S. Jordan, N. G. Beskrovnaya

The reported nightly mean value of the circular polarization of optical emission observed from the close binary system AE Aqr is 0.06% (+-) 0.01%. We discuss a possibility that the observed polarized radiation is emitted mainly by the white dwarf or its vicinity. We demonstrate that this hypothesis is rather unlikely since the contribution of the white dwarf

Keiji Saito, Seiji Miyashita

We study mechanism of magnetic energy transport, motivated by recent measurements of the thermal conductivity in low dimensional quantum magnets. We point out a possible mechanism of enhancement of the thermal conductivity in gapped magnetic system, where the magnetic energy transport plays a crucial role. This mechanism gives an interpretation for the recen

S. E. Massen, Ch. C. Moustakidis, C. P. Panos

It is shown that a similar functional form $S=a+b\ln N$ holds approximately for the information entropy S as function of the number of particles N for atoms, nuclei and atomic clusters (fermionic systems) and correlated boson-atoms in a trap (bosonic systems). It is also seen that rigorous inequalities previously found to hold between S and the kinetic energ

Fabrizio Dolcini, Arianna Montorsi

We investigate the one-dimensional Hubbard model with an additional bond-charge interaction, recently considered in the description of compounds that exhibit strong 1D features above the temperature of ordered phases. The partition function of the model is exactly calculated for a value of the bond-charge coupling; the behavior of the specific heat and spin

Vladimir Baryshevsky

New experiment arrangement to study spin rotation and oscillation of particles of gas target through which beam of high energy particles passes is discussed. Such experiment arrangement make it realizable for storage ring and allows to study zero-angle scattering amplitude at highest possible energies. Life-time of particle beam in storage ring can reach sev