May 2006 arXiv papers — page 16

J. Borissova, V. D. Ivanov, D. Minniti, D. Geisler

Massive clusters are more often found in actively star forming galaxies than in quiescent ones, similar to the Milky Way. We have carried out an extensive survey of obscured Milky Way clusters to determine whether our Galaxy is still forming such objects. Near-infrared spectral classification of some probable cluster members was used to derive the distances

Erik Brubaker

The mass of the top quark M_top is interesting both as a fundamental parameter of the standard model and as an important input to precision electroweak tests. The Collider Detector at Fermilab (CDF) has a robust program of top quark mass analyses, including the most precise single measurement, M_top = 173.4 +/- 2.8 GeV/c^2, using 680 pb^-1 of ppbar collision

Fionn Murtagh

We begin with pervasive ultrametricity due to high dimensionality and/or spatial sparsity. How extent or degree of ultrametricity can be quantified leads us to the discussion of varied practical cases when ultrametricity can be partially or locally present in data. We show how the ultrametricity can be assessed in text or document collections, and in time se

Concezio Bozzi

Recent results on inclusive and exclusive semileptonic B decays from B Factories are presented. The status and perspectives of the determination of the CKM matrix elements Vub and Vcb with semileptonic B decays is discussed.

D. Bar

We have previously discussed the characteristics of the gravitational waves (GW) and have, theoretically, shown that, like the corresponding electromagnetic (EM) waves, they also demonstrate, under certain conditions, holographic properties. In this work we have expanded this discussion and show that the assumed gravitational holographic images may, theoreti

Matthew Ando, Christopher P. French, Nora Ganter

We explain the relationship between the sigma orientation and Witten genus on the one hand and the two-variable elliptic genus on the other. We show that if E is an elliptic spectrum, then the Theorem of the Cube implies the existence of canonical SU-orientation of the associated spectrum of Jacobi forms. In the case of the elliptic spectrum associated to th

Washington Taylor

This elementary introduction to string field theory highlights the features and the limitations of this approach to quantum gravity as it is currently understood. String field theory is a formulation of string theory as a field theory in space-time with an infinite number of massive fields. Although existing constructions of string field theory require expan

X. F. Wang, Tapash Chakraborty

Coulomb screening and excitation spectra of electrons in a graphene layer with spin-orbit interaction (SOI) is studied in the random phase approximation. The SOI opens a gap between the valence and conduction bands of the semi-metal Dirac system and reshapes the bottom and top of the bands. As a result, we have observed a dramatic change in the long-waveleng

Daniel S. Freed, Gregory W. Moore, Graeme Segal

We develop a group-theoretical approach to the formulation of generalized abelian gauge theories, such as those appearing in string theory and M-theory. We explore several applications of this approach. First, we show that there is an uncertainty relation which obstructs simultaneous measurement of electric and magnetic flux when torsion fluxes are included.

Leonid Chuzhoy, Marcelo A. Alvarez, Paul R. Shapiro

At the beginning of the reionization epoch, radiation sources produce fluctuations in the redshifted 21-cm background. We show that different types of sources (such as miniquasars, Pop II and III stars, supernovae, etc.) produce distinct signatures in the 21-cm signal radial profiles and statistical fluctuations, through which they can be identified. Further

Keshav Dasgupta, Marc Grisaru, Rhiannon Gwyn, Sheldon Katz

In this work we explore many directions in the framework of gauge-gravity dualities. In type IIB theory we give an explicit derivation of the local metric for five branes wrapped on rigid two-cycles. Our derivation involves various interplays between warp factors, dualities and fluxes and the final result confirms our earlier predictions. We also find a nove

Daniel S. Freed, Gregory W. Moore, Graeme Segal

In the ordinary quantum Maxwell theory of a free electromagnetic field, formulated on a curved 3-manifold, we observe that magnetic and electric fluxes cannot be simultaneously measured. This uncertainty principle reflects torsion: fluxes modulo torsion can be simultaneously measured. We also develop the Hamilton theory of self-dual fields, noting that they

Ben Craps

These proceedings are based on lectures delivered at the "RTN Winter School on Strings, Supergravity and Gauge Theories", CERN, January 16 - January 20, 2006. The school was mainly aimed at Ph.D. students and young postdocs. The lectures start with a brief introduction to spacetime singularities and the string theory resolution of certain static sing

Borun D. Chowdhury

It is shown that $exp(-2 Im(\int p dr))$ is not invariant under canonical transformations in general. Specifically for shells tunneling out of black holes, this quantity is not invariant under canonical transformations. It can be interpreted as the transmission coefficient only in the cases in which it is invariant under canonical transformations. Although s

Igor Belegradek, Denis Osin

We show that for any non--elementary hyperbolic group $H$ and any finitely presented group $Q$, there exists a short exact sequence $1\to N\to G\to Q\to 1$, where $G$ is a hyperbolic group and $N$ is a quotient group of $H$. As an application we construct a hyperbolic group that has the same $n$--dimensional complex representations as a given finitely genera

Sudip Bhattacharyya

We analyze archival Rossi X-ray Timing Explorer (RXTE) Proportional Counter Array (PCA) data of the low mass X-ray binary (LMXB) system XB 1254-690. We calculate colour-colour diagram, hardness-intensity diagram and power spectra of this source, associate its broad low-frequency timing features with the portions of the colour-colour diagram, and establish th

Stefan Hollands, Akihiro Ishibashi, Robert M. Wald

A key result in the proof of black hole uniqueness in 4-dimensions is that a stationary black hole that is ``rotating''--i.e., is such that the stationary Killing field is not everywhere normal to the horizon--must be axisymmetric. The proof of this result in 4-dimensions relies on the fact that the orbits of the stationary Killing field on the horiz

Eanna E. Flanagan

The fourth order Weyl gravity theory of Mannheim and Kazanas is based on replacing the Einstein-Hilbert action with the square of the Weyl tensor, and on modifying the matter action of the standard model of particle physics to make it conformally invariant. This theory has been suggested as a model of both dark matter and dark energy. We argue that the confo

Abdul Salam Jarrah, Reinhard Laubenbacher, Brandilyn Stigler, Michael Stillman

Multivariate polynomial dynamical systems over finite fields have been studied in several contexts, including engineering and mathematical biology. An important problem is to construct models of such systems from a partial specification of dynamic properties, e.g., from a collection of state transition measurements. Here, we consider static models, which are

Gabor Csardi, Katherine Strandburg, Laszlo Zalanyi, Jan Tobochnik

In this paper we present the application of a novel methodology to scientific citation and collaboration networks. This methodology is designed for understanding the governing dynamics of evolving networks and relies on an attachment kernel, a scalar function of node properties, which stochastically drives the addition and deletion of vertices and edges. We

Maxim Pospelov

We point out that the existence of metastable, tau > 10^3 s, negatively charged electroweak-scale particles (X^-) alters the predictions for lithium and other primordial elemental abundances for A>4 via the formation of bound states with nuclei during BBN. In particular, we show that the bound states of X^- with helium, formed at temperatures of about T=10^8

Steven B. Giddings

The black hole information paradox apparently indicates the need for a fundamentally new ingredient in physics. The leading contender is nonlocality. Possible mechanisms for the nonlocality needed to restore unitarity to black hole evolution are investigated. Suggestions that such dynamics arises from ultra-planckian modes in Hawking's derivation are inv

Sourav Chatterjee, Jason Fulman, Adrian Rollin

General Berry-Esseen bounds are developed for the exponential distribution using Stein's method. As an application, a sharp error term is obtained for Hora's result that the spectrum of the Bernoulli-Laplace Markov chain has an exponential limit. This is the first use of Stein's method to study the spectrum of a graph with a non-normal limit.

Christopher P. Herzog

We investigate some universal features of AdS/CFT models of heavy quark energy loss. In addition, as a specific example, we examine quark damping in the spinning D3-brane solution dual to N=4 SU(N_c) super Yang-Mills at finite temperature and R-charge chemical potential.

G. G. Amosov

We investigate the Weyl channels being covariant with respect to the maximum commutative group of unitary operators. This class includes the quantum depolarizing channel and the "two-Pauli" channel as well. Then, we show that our estimation of the output entropy for a tensor product of the phase damping channel and the identity channel based upon the

Mariana P. Lima, Daniel Muller

As it is well known the topology of space is not totally determined by Einstein's equations. It is considered a massless scalar quantum field in a static Euclidean space of dimension 3. The expectation value for the energy density in all compact orientable Euclidean 3-spaces are obtained in this work as a finite summation of Epstein type zeta functions.

Dominic W. Berry, Mark R. Dowling

We have found that for a wide range of two-qubit Hamiltonians the canonical-ensemble thermal state is entangled in two distinct temperature regions. In most cases the ground state is entangled; however we have also found an example where the ground state is separable and there are still two regions. This demonstrates that the qualitative behavior of entangle

Min-xin Huang, Albrecht Klemm

We use the holomorphic anomaly equation to solve the gravitational corrections to Seiberg-Witten theory and a two-cut matrix model, which is related by the Dijkgraaf-Vafa conjecture to the topological B-model on a local Calabi-Yau manifold. In both cases we construct propagators that give a recursive solution in the genus modulo a holomorphic ambiguity. In t

M. Blanke, A. J. Buras, A. Poschenrieder, C. Tarantino

We calculate a number of observables related to particle-antiparticle mixing in the Littlest Higgs model with T-parity (LHT). The resulting effective Hamiltonian for Delta F=2 transitions agrees with the one of Hubisz et al., but our phenomenological analysis goes far beyond the one of these authors. In particular, we point out that the presence of mirror fe

D. Reese, F. Lignières, M. Rieutord

Context: With the launch of space missions devoted to asteroseismology (like COROT), the scientific community will soon have accurate measurements of pulsation frequencies in many rapidly rotating stars. Aims: The present work focuses on the effects of rotation on pulsations of rapidly rotating stars when both the Coriolis and centrifugal accelerations requi

Mordecai-Mark Mac Low, Jayashree Toraskar, Jeffrey S. Oishi, Tom Abel

The nature of ultracompact H II regions (UCHRs) remains poorly determined. In particular, they are about an order of magnitude more common than would be expected if they formed around young massive stars and lasted for one dynamical time, around 10^4 yr. We here perform three-dimensional numerical simulations of the expansion of an H II region into self-grav

R. N. Ghalati, N. Kiriushcheva, S. V. Kuzmin

Using the Gitman-Lyakhovich-Tyutin generalization of the Ostrogradsky method for analyzing singular systems, we consider the Hamiltonian formulation of metric and tetrad gravities in two-dimensional Riemannian spacetime treating them as constrained higher-derivative theories. The algebraic structure of the Poisson brackets of the constraints and the correspo

D. Buchholz

We present recent DO results based on approximately 1 fb$^{-1}$ of $p \bar{p}$ collisions at $\sqrt{s} = 1.96$ TeV recorded at the Fermilab Tevatron. Preliminary results on a search for the flavor changing neutral current process $D^+\to \pi^+\mu^+\mu^-$, a measurement of the CP violation parameter in $B$ mixing, $\epsilon_B$, and a two sided limit on the $B

UTfit Collaboration, M. Bona, M. Ciuchini, E. Franco

The status of the Unitarity Triangle beyond the Standard Model including the most recent results on Delta m_s, on dilepton asymmetries and on width differences is presented. Even allowing for general New Physics loop contributions the Unitarity Triangle must be very close to the Standard Model result. With the new measurements from the Tevatron, we obtain fo

Lorenzo Iorio

In this paper we address the following question: do the recent advances in the orbit determination of the major natural satellites of Saturn obtained with the analysis of the first data sets from the Cassini mission allow to detect the general relativistic gravitoelectric orbital precessions of such moons? The answer is still negative. The present-day down-t

Troels Harmark, Vasilis Niarchos, Niels A. Obers

We study a set of asymmetric deformations of non-critical superstring theories in various dimensions. The deformations arise as Kaehler and complex structure deformations of an orthogonal two-torus comprising of a parallel and a transverse direction in the near-horizon geometry of NS5-branes. The resulting theories have the following intriguing features: Spa

D. Besson, S. Razzaque, J. Adams, P. Harris

We present limits on ultra-high energy (UHE; E(nu)>1 PeV) neutrino fluxes from gamma-ray bursts (GRBs), based on recently presented data, limits, and simulations from the RICE experiment. We use data from five recorded transients with sufficient photon spectral shape and redshift information to derive an expected neutrino flux, assuming that the observed pho

L. Ladino, J. W. Brill, M. Freamat, M. Uddin

We have studied the charge density wave (CDW) repolarization dynamics in blue bronze by applying square-wave voltages of different frequencies to the sample and measuring the changes in infrared transmittance, proportional to CDW strain. The frequency dependence of the electro-transmittance was fit to a modified harmonic oscillator response and the evolution

N. Kalton, S. V. Konyagin, L. Vesely

A continuous quadratic form ("quadratic form", in short) on a Banach space $X$ is: (a) delta-semidefinite (i.e., representable as a difference of two nonnegative quadratic forms) if and only if the corresponding symmetric linear operator $T\colon X\to X^*$ factors through a Hilbert space; (b) delta-convex (i.e., representable as a difference of two c

P. G. Jonker, G. Nelemans, C. G. Bassa

In this Paper we report on phase resolved I-band optical spectroscopic and photometric observations of CirX-1 obtained with the Very Large Telescope. The spectra are dominated by Paschen absorption lines at nearly all orbital phases except near phase zero (coinciding with the X-ray dip) when the absorption lines are filled-in by broad Paschen emission lines.

H. Ohta, Y. Itoh, C. Michioka, K. Yoshimura

We report 23Na NMR studies of the polycrystalline samples of double-layer hydrated cobalt oxides NaxCoO2.yH2O (x ~ 0.35 and y ~ 1.3) with the superconducting transition temperatures Tc < 1.8K and ~4.5K, and the dehydrated NaxCoO2 (x ~ 0.35). The hyperfine field and the electric field gradient at the Na sites in the non-hydrated Na0.7CoO2 and the dehydrated N

M. LUCA

EDELWEISS is a direct dark matter search using cryogenic germanium heat-ionisation detectors, located in the Modane underground laboratory beneath the Alps. We summarize the final results of EDELWEISS I, which deployed up to almost one kg of detectors in its final stage. EDELWEISS II recently started commissioning runs. With an increased detection mass and b

M. Grajcar, Yu-xi Liu, Franco Nori, A. M. Zagoskin

We propose a coupling scheme, where two or more flux qubits with different eigenfrequencies share Josephson junctions with a coupler loop devoid of its own quantum dynamics. Switchable two-qubit coupling is realized by tuning the frequency of the AC magnetic flux through the coupler to a combination frequency of two of the qubits. The coupling allows any or

Gioacchino Ranucci, Marco Rovere

In this work a detailed spectral analysis for periodicity search of the time series of the 8B solar neutrino flux released by the SNO Collaboration is presented. The data have been publicly released with truncation of the event times to the unit of day (1 day binning); they are thus suited to undergo the traditional Lomb-Scargle analysis for periodicity inve

M. Csanad, T. Csorgo, R. A. Lacey, B. Lorstad

Recent PHOBOS measurements of the excitation function for the pseudo-rapidity dependence of elliptic flow in Au+Au collisions at RHIC, have posed a significant theoretical challenge. We show here that these data are described by the Buda-Lund model. A universal scaling curve, predicted by the Buda-Lund hydro model, describes not only PHOBOS data, but also re

Takehiko Asaka, Mikko Laine, Mikhail Shaposhnikov

Sterile neutrinos with masses in the keV range are considered to be a viable candidate for warm dark matter. The rate of their production through active-sterile neutrino transitions peaks, however, at temperatures of the order of the QCD scale, which makes it difficult to estimate their relic abundance quantitatively, even if the mass of the sterile neutrino

Bassam Kojok

We prove global well-posedness for the Cauchy problem associated with the Kadomotsev-Petviashvili-Burgers equation (KPBII) in $\mathbb R^2$ when the initial value belongs to the anisotropic Sobolev space $H^{s_1,s_2}(\mathbb R^2)$ for all $s_1>-\frac12$ and $s_2\geq0$. On the other hand, we prove in some sense that our result is sharp.

Shahid N. Afridi, Khalid Khan

We have derived generalized ideal gas equations for a structureful universe consisting of all forms of matters. We have assumed a universe that contains superclusters. Superclusters are then made of clusters. Each cluster can be further divided into smaller ones and so on. We have derived an expression for the entropy of such a universe. Our model is rather

Henry Wilton

A celebrated theorem of Marshall Hall Jr. implies that finitely generated free groups are subgroup separable and that all of their finitely generated subgroups are retracts of finite-index subgroups. We use topological techniques inspired by the work of Stallings to prove that all limit groups share these two properties. This answers a question of Sela.

Makoto Umeki

The cascade-shell model of turbulence with six real variables originated by Gledzer is studied numerically using Mathematica 5.1. Periodic, doubly-periodic and chaotic solutions and the routes to chaos via both frequency-locking and period-doubling are found by the Poincaré plot of the first mode $v_1$. The circle map on the torus is well approximated by the

J. Salo, F. W. J. Hekking, J. P. Pekola

We present a general formalism based on scattering theory to calculate quantum correlation functions involving several time-dependent current operators. A key ingredient is the causality of the scattering matrix, which allows one to deal with arbitrary correlation functions. Our formalism might be useful in view of recent developments in full counting statis

Benno List

The production of charm and beauty quarks in ep collisions at HERA has been studied by the H1 and ZEUS collaborations. Charm production is generally well described in total rate and in shape by next to leading order (NLO) calculations in perturbative quantum chromodynamics (QCD), although in specific phase space corners the NLO calculations underestimate the

Edward M. Cackett, Rudy Wijnands, Manuel Linares, Jon M. Miller

We present Chandra and XMM-Newton X-ray observations that monitor the neutron star cooling of the quasi-persistent neutron star X-ray transients KS 1731-260 and MXB 1659-29 for approximately 4 years after these sources returned to quiescence from prolonged outbursts. In both sources the outbursts were long enough to significantly heat the neutron star crust

Vincent Guirardel, Gilbert Levitt

Let G be a finitely generated group. Two simplicial G-trees are said to be in the same deformation space if they have the same elliptic subgroups (if H fixes a point in one tree, it also does in the other). Examples include Culler-Vogtmann&#39;s outer space, and spaces of JSJ decompositions. We discuss what features are common to trees in a given deformation

Yury A. Koksharov

Examining textbooks of thermodynamics we have not able to find a proof of increasing of entropy under free adiabatic expansion in vacuum based on the state equation of the Van der Waals gas. This communication remedies the situation. During proving we faced with an amusing example of apparent violation of thermodynamics second law.

E. Alvarez, J. Bernabeu, M. Nebot

In this paper we discuss experimental consequences of a novel kind of CPT violation which would manifest itself in the symmetry of the entangled initial state of $B ^0$ and $\bar B ^0$ through their loss of indistinguishability. The ``wrong&#39;&#39; symmetry component is proportional to $ω$. We focus our theoretical study on the $Δt$-dependence of observabl

Andrey Katz, Yael Shadmi

We consider Lorentz violation in supersymmetric extensions of the standard model. We perform a spurion analysis to show that, in the simplest natural constructions, the resulting supersymmetry-breaking masses are tiny. In the process, we argue that one of the strongest bounds on Lorentz violation in the photon Lagrangian, which comes from the absence of bire

Nachum Dershowitz, Ziyad Hanna, Alexander Nadel

We propose a new algorithm for minimal unsatisfiable core extraction, based on a deeper exploration of resolution-refutation properties. We provide experimental results on formal verification benchmarks confirming that our algorithm finds smaller cores than suboptimal algorithms; and that it runs faster than those algorithms that guarantee minimality of the

Kalle Kytölä, Antti Kemppainen

We study SLE reversibility and duality using the Virasoro structure of the space of local martingales. For both problems we formulate a setup where the questions boil down to comparing two processes at a stopping time. We state algebraic results showing that local martingales for the processes have enough in common. When one has in addition integrability, th

Indranil Biswas, Vicente Muñoz

We study the rational homotopy of the moduli space ${\mathcal N}_X$ of stable vector bundles of rank two and fixed determinant of odd degree over a compact connected Riemann surface $X$ of genus $g\geq 2$. The symplectic group $Aut(H_1(X,{\mathbb Z}))=Sp(2g,{\mathbb Z})$ has a natural action on the rational homotopy groups $π_n({\mathcal N}_X) \otimes {\math

Kouji Nakamura

Gauge invariant treatments of the second order cosmological perturbation in a four dimensional homogeneous isotropic universe filled with the perfect fluid are completely formulated without any gauge fixing. We derive all components of the Einstein equations in the case where the first order vector and tensor modes are negligible. These equations imply that

Fumiko Takagi, Macoto Kikuchi

We investigated the structural relaxation of myosin motor domain from the pre-power stroke state to the near-rigor state using molecular dynamics simulation of a coarse-grained protein model. To describe the structural change, we propose a &#34;dual Go-model,&#34; a variant of the Go-like model that has two reference structures. The nucleotide dissociation p

Kouji Nakamura

Along the general framework of the gauge invariant perturbation theory developed in the papers [K. Nakamura, Prog. Theor. Phys. {\bf 110} (2003), 723; {\it ibid}, {\bf 113} (2005), 481.], we formulate the second order gauge invariant cosmological perturbation theory in a four dimensional homogeneous isotropic universe. We consider the perturbations both in t

A. E. Rastegin

In the present paper, the trace distance is exposed within the quantum operations formalism. The definition of the trace distance in terms of a maximum over all quantum operations is given. It is shown that for any pair of different states, there are an uncountably infinite number of maximizing quantum operations. Conversely, for any operation of the describ

Matthew Kahle

In a seminal paper, Erdos and Renyi identified the threshold for connectivity of the random graph G(n,p). In particular, they showed that if p >> log(n)/n then G(n,p) is almost always connected, and if p << log(n)/n then G(n,p) is almost always disconnected, as n goes to infinity. The clique complex X(H) of a graph H is the simplicial complex with all comple

Kazuhide Ichikawa, Masahiro Kawasaki, Toyokazu Sekiguchi, Tomo Takahashi

We investigate how the nature of dark energy affects the determination of the curvature of the universe from recent observations. For this purpose, we consider the constraints on the matter and dark energy density using observations of type Ia supernovae, baryon acoustic oscillation peak and cosmic microwave background with several types of dark energy equat

Tao Qin, Meisheng Zhao, Yongde Zhang

The process of quantum teleportation can be considered as a quantum channel. The exact classical capacity of the continuous variable teleportation channel is given. Also, the channel fidelity is derived. Consequently, the properties of the continuous variable quantum teleportation are discussed and interesting results are obtained.

Yong Hu, Zheng-Wei Zhou, Guang-Can Guo

We investigate the non-nearest-neighbor interaction effect in 1-D spin-1/2 chain model. In many previous schemes this long-range coupling is omitted because of its relative weak strength compared with the nearest-neighbor coupling. We show that the quantum gate deviation induced by the omitted long-range interaction depends on not only its strength but also

O. Arcizet, P. -F. Cohadon, T. Briant, M. Pinard

We experimentally demonstrate the high-sensitivity optical monitoring of a micro-mechanical resonator and its cooling by active control. Coating a low-loss mirror upon the resonator, we have built an optomechanical sensor based on a very high-finesse cavity (30000). We have measured the thermal noise of the resonator with a quantum-limited sensitivity at the

Indranil Chakrabarty, A. K. Pati, Satyabrata Adhikari

It is known that the stronger no-cloning theorem and the no-deleting theorem taken together provide the permanence property of quantum information. Also, it is known that the violation of the no-deletion theorem would imply signalling. Here, we show that the violation of the stronger no-cloning theorem could lead to signalling. Furthermore, we prove the stro

J. Britton, D. Leibfried, J. Beall, R. B. Blakestad

The prospect of building a quantum information processor underlies many recent advances ion trap fabrication techniques. Potentially, a quantum computer could be constructed from a large array of interconnected ion traps. We report on a micrometer-scale ion trap, fabricated from bulk silicon using micro-electromechanical systems (MEMS) techniques. The trap g

Mathias Kuhnt, Ingmar Glauche, Martin Greiner

The observed structure of protein interaction networks is corrupted by many false positive/negative links. This observational incompleteness is abstracted as random link removal and a specific, experimentally motivated (spoke) link rearrangement. Their impact on the structural properties of gene-duplication-and-mutation network models is studied. For the deg

S. L. Arsenjev

A fluid motion through the flow element is presented in the kind of an autooscillating system with the distributed parameters: mass, elasticity, viscosity. The system contains a self-excited oscillator and possesses a self-regulation on base of the intrinsic voluntary negative servo output feedback. The interaction dynamics of the submerged jet, out-flowing

S. C. Hsu, X. Z. Tang

A spherical tokamak (ST) with a plasma center column (PCC) can be formed via driven magnetic relaxation of a screw pinch plasma. An ST-PCC could in principle eliminate many problems associated with a material center column, a key weakness of the ST reactor concept. This work summarizes the design space for an ST-PCC in terms of flux amplification, aspect rat

E. N. Egorov, Yu. A. Kalinin, A. A. Koronovskii, A. E. Hramov

The power of microwave generation in a nonrelativistic electron beam with virtual cathode formed in a static retarding electric field (low-voltage vircator system) has been studied experimentally and by means of numerical simulation within the framework of a one-dimensional theory. The limits of applicability of the one-dimensional theory have been experimen

P. V. Coveney, G. De Fabritiis, M. J. Harvey, S. M. Pickles

Coupled models are set to become increasingly important in all aspects of science and engineering as tools with which to study complex systems in an integrated manner. Such coupled, hybrid simulations typically communicate data between the component models of which they are comprised relatively infrequently, and so a Grid is expected to present an ideal arch

Vitor H. A. Dias, Jorge O. O. Franco, Andres R. R. Papa

Records of Dst, Kp and Sym-H indexes are analyzed looking for evidences of possible precursors for magnetic storms. To accomplish this task the main magnetic storms were located and some periods immediately before storms and some periods well before them studied. Statistical properties of both types of periods were then compared. In particular, were compared

G. Brodin, L. Stenflo, P. K. Shukla

The resonant coupling between Alfvén waves is reconsidered. New results are found for cold plasmas there temperature effects are negligible.

Liang Sun

The essence of shear instability is fully revealed both mathematically and physically. A general sufficient and necessary stable criterion is obtained analytically within linear context. It is the analogue of Kelvin-Arnol&#39;d theorem, i.e., the stable flow minimizes the kinetic energy associated with vorticity. Then the mechanism of shear instability is ex

Tom G. Mackay, Akhlesh Lakhtakia

A composite material comprising randomly distributed spherical particles of two different isotropic dielectric-magnetic materials is homogenized using the second-order strong-property-fluctuation theory in the long-wavelength approximation. Whereas neither of the two constituent materials by itself supports planewave propagation with negative phase velocity

Akihiro Isomura, Nobuyuki Magome, Masahiro I. Kohira, Kenichi Yoshikawa

To identify the optimum conditions for the optical trapping of a droplet under microgravity, we theoretically analyzed the efficiency of trapping with counter laser beams. We found that the distance between the two foci is an important parameter for obtaining stable trapping conditions. We also performed an optical trapping experiment with counter laser beam

Y. Tamayama, T. Nakanishi, K. Sugiyama, M. Kitano

We have experimentally realized Brewster&#39;s effect for transverse-electric waves with metamaterials. In dielectric media, Brewster&#39;s no-reflection effect arises only for transverse-magnetic waves. However, it has been theoretically predicted that Brewster&#39;s effect arises for TE waves under the condition that the relative permeability r is not equa

Boris A. Gelman, Edward V. Shuryak, Ismail Zahed

We analyze the screening and bulk energy of a classical and strongly interacting plasma of color charges, a model we recently introduced for the description of a quark-gluon plasma at T=(1-3)Tc. The partition function is organized around the Debye-Huckel limit. The linear Debye-Huckel limit is corrected by a virial expansion. For the pressure, the expansion

S. Erturk, I. Boztosun, Y. Kucuk, M. Karakoc

We present the failure of the standard coupled-channels method in explaining the inelastic scattering together with other observables such as elastic scattering, excitation function and fusion data. We use both microscopic double-folding and phenomenological deep potentials with shallow imaginary components. We argue that the solution of the problems for the

The PS185 collaboration, K . D. Paschke, B. Quinn, A. Berdoz

The reaction anti-proton + proton -> anti-Λ+ Λ-> anti-proton + π^+ + proton + π^- has been measured with high statistics at anti-proton beam momentum of 1.637 GeV/c. The use of a transversely-polarized frozen-spin target combined with the self-analyzing property of Λ/anti-Λdecay allows access to unprecedented information on the spin structure of the interact

Gabriela Ovando

The Adler Kostant Symes [A-K-S] scheme is used to describe mechanical systems for quadratic Hamiltonians of $\mathbb R^{2n}$ on coadjoint orbits of the Heisenberg Lie group. The coadjoint orbits are realized in a solvable Lie algebra $\mathfrak g$ that admits an ad-invariant metric. Its quadratic induces the Hamiltonian on the orbits, whose Hamiltonian syste

R. Cianci, S. Vignolo, D. Bruno

The formulation of General Relativity presented in math-ph/0506077 and the Hamiltonian formulation of Gauge theories described in math-ph/0507001 are made to interact. The resulting scheme allows to see General Relativity as a constrained Gauge theory.

P. Jacob, P. Mathieu

A lattice-path description of $K$-restricted jagged partitions is presented. The corresponding lattice paths can have peaks only at even $x$ coordinate and the maximal value of the height cannot be larger than $K-1$. Its weight is twice that of the corresponding jagged partitions. The equivalence is demonstrated at the level of generating functions. A biject

Shoichi Fujimori

We give a mathematical foundation for, and numerical demonstration of, the existence of mean curvature 1 surfaces of genus 1 with either two elliptic ends or two hyperbolic ends in de Sitter 3-space. An end of a mean curvature 1 surface is an ``elliptic end&#39;&#39; (resp. a ``hyperbolic end&#39;&#39;) if the monodromy matrix at the end is diagonalizable wi

Ilya Kapovich, Martin Lustig

We prove that for $k\ge 5$ there does not exist a continuous map $\partial CV(F_k)\to\mathbb PCurr(F_k)$ that is either $Out(F_k)$-equivariant or $Out(F_k)$-anti-equivariant. Here $\partial CV(F_k)$ is the &#34;length-function&#34; boundary of Culler-Vogtmann&#39;s Outer space $CV(F_k)$, and $\mathbb PCurr(F_k)$ is the space of projectivized geodesic current

Mikhail V. Babich

The geometric model of the pathway linking Schlesinger and Garnier--Painlevé~6 systems based on an original orthonormalization of a set of elements in ${sl(2,\mathbb C)}$ is constructed. The explicit polynomial map of the Cartesian products of $n-2$ quadrics (the Zariski-topology chart of the phase space of the Garnier--Painlevé~6 system) into the phase spac

Thomas Kahl

Algebraic topological methods have been used successfully in concurrency theory, the domain of theoretical computer science that deals with parallel computing. L. Fajstrup, E. Goubault, and M. Raussen have introduced partially ordered spaces (pospaces) as a model for concurrent systems. In this paper it is shown that the category of pospaces under a fixed po

P. Ebenfelt, B. Lamel, D. Zaitsev

We introduce new biholomorphic invariants for real-analytic hypersurfaces in 2-dimensional complex space and show how they can be used to show that a hypersurface possesses few automorphisms. We give conditions, in terms of the new invariants, guaranteeing that the stability group is finite, and give (sharp) bounds on the cardinality of the stability group i

Evgeny Ivanov

We construct a nonlinear version of the d=1 off-shell N=8 multiplet (4,8,4), proceeding from a nonlinear realization of the superconformal group OSp(4*|4) in the N=8, d=1 analytic bi-harmonic superspace. The new multiplet is described by a double-charged analytic superfield q^{1,1} subjected to some nonlinear harmonic constraints which are covariant under th

M. M. Block, F. Halzen

Landshoff and Donnachie[hep-ph/0509240, (2005)] parametrize the energy behavior of pp and p\bar p scattering cross sections with five parameters, using: σ^+=56.08 s^{-0.4525}+21.70s^{0.0808} for pp, σ^-=98.39 s^{-0.4525}+21.70s^{0.0808} for p\bar p. Using the 4 analyticity constraints of Block and Halzen[M. M. Block and F. Halzen, Phys. Rev. D {\bf 72}, 0360

Piotr A. Raczka

The problem of precise evaluation of the perturbative QCD predictions at moderate energies is considered. Substantial renormalization scheme dependence of the perturbative predictions obtained with the conventional renormalization group improved perturbative approximants is discussed, using as an example the QCD effective charge appearing in the static inter

F. Spano&#39;

The current status of electroweak physics results from LEP is reviewed. Particular emphasis is placed on the latest results on the properties of the Z and W bosons. The updated status of the global electroweak fit to the standard model and the resulting standard model Higgs mass limits are presented.

Narayan Banerjee, Sudipta Das

In the present work, an attempt has been made to explain the recent cosmic acceleration with two mutually interacting scalar fields, one being the Brans-Dicke scalar field and the other a quintessence scalar field. Conditions have been derived for which the quintessence scalar field has an early oscillation and it grows during a later time to govern the dyna

A. Bhadra, K. Sarkar, D. P. Datta, K. K. Nandi

It is well known that, in contrast to general relativity, there are two conformally related frames, the Jordan frame and the Einstein frame, in which the Brans-Dicke theory, a prototype of generic scalar-tensor theory, can be formulated. There is a long standing debate on the physical equivalence of the formulations in these two different frames. It is shown

Ke Liu, Adnan Majeed, Nael B. Abu-Ghazaleh

Traffic analysis in Multi-hop Wireless Networks can expose the structure of the network allowing attackers to focus their efforts on critical nodes. For example, jamming the only data sink in a sensor network can cripple the network. We propose a new communication protocol that is part of the MAC layer, but resides conceptually between the routing layer and