December 2005 arXiv papers — page 32

Bernardo A. Huberman, Fang Wu

We describe an efficient incentive mechanism for P2P systems that generates a wide diversity of content offerings while responding adaptively to customer demand. Files are served and paid for through a parimutuel market similar to that commonly used for betting in horse races. An analysis of the performance of such a system shows that there exists an equilib

Sebastián Bengochea, Angel Talamona, Michel Parent

A growing category of vehicle-infrastructure cooperative (VIC) applications requires telematics software components distributed between an infrastructure-based management center and a number of vehicles. This article presents an approach based on a software framework, focusing on a Telematic Management System (TMS), a component suite aimed to run inside an i

Ram Somaraju, Leif W. Hanlen

Uncertainty principles for concentration of signals into truncated subspaces are considered. The ``classic'' uncertainty principle is explored as a special case of a more general operator framework. The time-bandwidth concentration problem is shown as a similar special case. A spatial concentration of radio signals example is provided, and it is show

Elitza N. Maneva, Amin Shokrollahi

We present a new model for LT codes which simplifies the analysis of the error probability of decoding by belief propagation. For any given degree distribution, we provide the first rigorous expression for the limiting error probability as the length of the code goes to infinity via recent results in random hypergraphs [Darling-Norris 2005]. For a code of fi

Kenton K. Yee

I describe recent developments in the rules governing registration and ownership of Internet and World Wide Web addresses or "domain names." I consider the idea that "virtual" properties like domain names are more similar to real estate than to trademarks. Therefore, it would be economically efficient to grant domain name owners stronger righ

A. F. Koenderink, A. Polman

We show that guiding of optical signals in chains of metal nanoparticles is subject to a surprisingly complex dispersion relation. Retardation causes the dispersion relation to split in two anticrossing branches, as common for polaritons. While huge radiation losses occur above the light line, just below the light line the micron-sized loss lengths are much

Gerardo Aquino, Luca Leuzzi, Theo M. Nieuwenhuizen

The Kovacs protocol, based on the temperature shift experiment originally conceived by A.J. Kovacs and applied on glassy polymers, is implemented in an exactly solvable model with facilitated dynamics. This model is based on interacting fast and slow modes represented respectively by spherical spins and harmonic oscillator variables. Due to this fundamental

L. V. Pourovskii, M. I. Katsnelson, A. I. Lichtenstein, L. Havela

Ab-initio relativistic dynamical mean-field theory is applied to resolve the long-standing controversy between theory and experiment in the "simple" face-centered cubic phase of plutonium called delta-Pu. In agreement with experiment, neither static nor dynamical magnetic moments are predicted. In addition, the quasiparticle density of states reprodu

Gao Xianlong, Marco Polini, M. P. Tosi, Vivaldo L. Campo,

We present an extensive numerical study of ground-state properties of confined repulsively interacting fermions on one-dimensional optical lattices. Detailed predictions for the atom-density profiles are obtained from parallel Kohn-Sham density-functional calculations and quantum Monte Carlo simulations. The density-functional calculations employ a Bethe-Ans

A. L. Kuzemsky

A brief survey of the author's works on the quantum theory of magnetism. Theoretical foundation and applications of the generalized spin-fermion (sp-d) exchange lattice model to various magnetic systems, e.g., rare-earth metals and compounds, and magnetic and diluted magnetic semiconductors are discussed briefly. The main emphasis is put on the dynamic b

Frédéric Douarche

In this short communication, I give a very simple derivation of the Jarzynski equality, which allows to compute the free energy difference of a body, which is driven between two equilibrium states $A$ and $B$ by an external (time-dependent) force, from the probability distribution function of the work done on the system, regardless of the nature of the trans

Michael M. Wolf, Gerardo Ortiz, Frank Verstraete, J. Ignacio Cirac

We investigate quantum phase transitions (QPTs) in spin chain systems characterized by local Hamiltonians with matrix product ground states. We show how to theoretically engineer such QPT points between states with predetermined properties. While some of the characteristics of these transitions are familiar, like the appearance of singularities in the thermo

C. S. Nelson, R. M. Kolagani, M. Overby, V. N. Smolyaninova

We report structural and electronic characterization of the charge order phase in Bi0.4Ca0.6MnO3 films, in which photoinduced resistivity changes have been observed at temperatures approaching room temperature. In all films, lattice distortions associated with the charge order are observed, and both the wavevectors and displacements of the distortions are in

Elke Pahl, Uwe Birkenheuer

The frozen local hole approximation (FLHA) is an adiabatic approximation which is aimed to simplify the correlation calculations of valence and conduction bands of solids and polymers. Within this approximation correlated local hole states (CLHSs) are explicitely generated by correlating local Hartree-Fock (HF) hole states. The hole orbital and its occupancy

A. O. Gogolin, A. Komnik

We analyse the full counting statistics (FCS) of the charge transport through the Anderson impurity model (AIM) and similar systems with a single conducting channel. The object of principal interest is the generating function for the cumulants of charge current distribution. We derive an exact analytic formula relating the FCS generating function to the self

Kevin Wood, C. Van den Broeck, R. Kawai, Katja Lindenberg

We present the simplest discrete model to date that leads to synchronization of stochastic phase-coupled oscillators. In the mean field limit, the model exhibits a Hopf bifurcation and global oscillatory behavior as coupling crosses a critical value. When coupling between units is strictly local, the model undergoes a continuous phase transition which we cha

R. Lortz, T. Tomita, Y. Wang, A. Junod

The superconducting transition in a single overdoped, detwinned YBa2Cu3Ox (YBCO) crystal is studied using four different probes. Whereas the AC and DC magnetic susceptibilities find a dominant transition at 88 K with a smaller effect near 92 K, the specific heat and electrical resistivity reveal only a single transition at 88 K and 92 K, respectively. Under

Rajneesh Atre, Prasanta K. Panigrahi, G. S. Agarwal

We present a large family of {\it{exact}} solitary wave solutions of the one dimensional Gross-Pitaevskii equation, with time-varying scattering length and gain/loss, in both expulsive and regular parabolic confinement regimes. The consistency condition governing the soliton profiles is shown to map on to a {\it{linear}} Schrödinger eigenvalue problem, there

B. I. Min, J. H. Shim, Min Sik Park, Kyoo Kim

The origin of the stabilized simple-cubic (SC) structure in Po is explored by using the first principle band calculations. We have found that the prime origin is the inherent strong spin-orbit (SO) interaction in Po, which suppresses the Peierls-like structural instability as usually occurs in p-bonded systems. Based on the systematic analysis of electronic

John A. Scales, Michael Batzle

One region of the electromagnetic spectrum that is relatively unexploited for materials characterization is the millimeter wave band (frequencies roughly between 40 and 300 GHz). Millimeter wave techniques involve free-space (non-contacting) measurements which have a length scale that makes them ideal for characterizing bulk properties of multicomponent comp

Wen Yang, Kai Chang

Rashba spin splitting (RSS) in biased semiconductor quantum wells is investigated theoretically based on the eight-band envelope function model. We find that at large wave vectors, RSS is both nonmonotonic and anisotropic as a function of in-plane wave vector, in contrast to the widely used linear and isotropic model. We derive an analytical expression for R

Nikola Milutinovic, Jane R. Rigby, Joseph R. Masiero, Ryan S. Lynch

We consider geometries and possible physical models for weak low ionization absorbers based on the relative incidence of low and high ionization absorption systems. We found a total of 16 metal-line systems, with low and/or high ionization absorption detected in our survey of weak low ionization absorption systems from the archive of HST/STIS data. The weak

Rudolph E. Schild, Marius Dekker

The brightnesses of supernovae are commonly understood to indicate that cosmological expansion is accelerating due to dark energy. However the entire discussion presumes a perfectly transparent universe because no effects of reddening associated with the interstellar extinction law are seen. We note that with two kinds of dark matter (baryonic and non-baryon

Dan Hooper, Scott Dodelson

It has been suggested that Gamma Ray Bursts (GRB) may enable the expansion rate of our Universe to be measured out to very high redshifts ($z \gsim 5$) just as type Ia supernovae have done at $z \sim$1--1.5. We explore this possibility here, and find that GRB have the potential to detect dark energy at high statistical significance, but they are unlikely to

Sergio Palomares-Ruiz, Andrei Irimia, Thomas J. Weiler

Detection of ultra-high energy neutrinos will be useful for unraveling the dynamics of the most violent sources in the cosmos and for revealing the neutrino cross-section at extreme energy. Above ~ 10^20 eV, neutrinos may well be the only cosmic primariies. Thus, it is important to know the acceptances (event rate/flux) of proposed air-shower experiments for

R. Millan-Gabet, J. D. Monnier, R. L. Akeson, L. Hartmann

We present new K-band long baseline interferometer observations of three young stellar objects of the FU Orionis class, V1057 Cyg, V1515 Cyg and Z CMa-SE, obtained at the Keck Interferometer during its commissioning science period. The interferometer clearly resolves the source of near-infrared emission in all three objects. Using simple geometrical models w

Sebastien Bongard, E. Baron, G. Smadja, David Branch

Type Ia supernovae have played a crucial role in the discovery of the dark energy, via the measurement of their light curves and the determination of the peak brightness via fitting templates to the observed lightcurve shape. Two spectroscopic indicators are also known to be well correlated with peak luminosity. Since the spectroscopic luminosity indicators

Lei Shi, Qiusheng Gu, Zhixin Peng

In order to study the circumnuclear star-forming activity along the Hubble sequence, we cross-correlate the Sloan Digital Sky Survey Data Release 2 (SDSS DR2) with the Third Reference Catalog of Bright Galaxies (RC3) to derive a large sample of 1015 galaxies with both morphological and spectral information. Among these, 385 sources are classified as star-for

Anthony J. Remijan, J. M. Hollis

We report high spatial resolution VLA observations of the low-mass star-forming region IRAS 16293-2422 using four molecular probes: ethyl cyanide (CH$_3$CH$_2$CN), methyl formate (CH$_3$OCHO), formic acid (HCOOH), and the ground vibrational state of silicon monoxide (SiO). Ethyl cyanide emiss ion has a spatial scale of $\sim20''$ and encompasses bina

Kishore N. Ananda, Marco Bruni

We investigate the general relativistic dynamics of Robertson-Walker models with a non-linear equation of state (EoS), focusing on the quadratic case P = P_0 + αρ+ βρ^2. This may be taken to represent the Taylor expansion of any arbitrary barotropic EoS, P(ρ). With the right combination of P_0, αand β, it serves as a simple phenomenological model for dark en

Y. Xu, M. J. Reid, X. W. Zheng, K. M. Menten

We have measured the distance to the massive star-forming region W3OH in the Perseus spiral arm of the Milky Way to be 1.95 $\pm$ 0.04 kilo-parsecs ($5.86\times10^{16}$ km). This distance was determined by triangulation, with the Earth's orbit as one segment of a triangle, using the Very Long Baseline Array. This resolves a long-standing problem of a fac

Guillermo Gonzalez

Results from detailed spectroscopic analyses of stars hosting massive planets are employed to search for trends between abundances and condensation temperatures. The elements C, S, Na, Mg, Al, Ca, Sc, Ti, V, Cr, Mn, Fe, Ni and Zn are included in the analysis of 64 stars with planets and 33 comparison stars. No significant trends are evident in the data. This

A. Ecuvillon, G. Israelian, N. C. Santos, M. Mayor

We present the [X/H] trends as function of the elemental condensation temperature Tc in 88 planet host stars and in a volume-limited comparison sample of 33 dwarfs without detected planetary companions. We gathered homogeneous abundance results for many volatile and refractory elements spanning a wide range of Tc, from a few dozens to several hundreds kelvin

D. Santos, E. Moulin, F. Mayet, J. Macias-Perez

The project of a micro-TPC matrix of chambers of \hetrois for direct detection of non-baryonic dark matter is presented. The privileged properties of He3 are highlighted. The double detection (ionization - projection of tracks) is explained and its rejection evaluated. The potentialities of MIMAC-He3 for supersymmetric dark matter search are discussed.

G. Gilli, G. Israelian, A. Ecuvillon, N. C. Santos

This work presents a uniform and homogeneous study of chemical abundances of refractory elements in 101 stars with and 94 without known planetary companions. We carry out an in-depth investigation of the abundances of Si, Ca, Sc, Ti, V, Cr, Mn, Co, Ni, Na, Mg and Al. The new comparison sample, spanning the metallicity range -0.70< [Fe/H]< 0.50, fills the gap

Kaisey S. Mandel, Matias Zaldarriaga

We describe the effects of weak gravitational lensing by cosmological large scale structure on the diffuse emission of 21 centimeter radiation from neutral hydrogen at high redshifts during the era of reionization. The ability to observe radial information through the frequency, and thus three-dimensional regions of the background radiation at different reds

A. I. Chugunov

We study eigenmodes of acoustic oscillations of high multipolarity l ~ 100 - 1000 and high frequency (~100 kHz), localized in neutron star envelopes. We show that the oscillation problem is self-similar. Once the oscillation spectrum is calculated for a given equation of state (EOS) in the envelope and given stellar mass M and radius R, it can be rescaled to

Sidney van den Bergh

The luminosity distribution of globular clusters shows a dramatic dependence on parent galaxy luminosity. Dwarf galaxies contain far more faint globulars than do luminous galaxies. This difference is significant at the 99.7% level. On the other hand the luminosity distribution of globular clusters in dwarf galaxies does not appear to depend strongly on their

D. Watson, J. N. Reeves, J. Hjorth, J. P. U. Fynbo

Gamma-ray burst (GRB) 050904 is the most distant X-ray source known, at z=6.295, comparable to the farthest AGN and galaxies. Its X-ray flux decays, but not as a power-law; it is dominated by large variability from a few minutes to at least half a day. The spectra soften from a power-law with photon index Gamma=1.2 to 1.9, and are well-fit by an absorbed pow

Andrea Bianconi, Marco Radici

We present Monte Carlo simulations of the Sivers effect in the polarized Drell-Yan $pp^\uparrow \to μ^+ μ^- X$ process at the center-of-mass energy $\sqrt{s}=200$ GeV reachable at the Relativistic Heavy-Ion Collider (RHIC) of BNL. We use two different parametrizations for the Sivers function, one deduced from the analysis of Semi-Inclusive Deep-Inelastic Sca

J. G. Peixoto de Faria

We present the general solutions for the classical and quantum dynamics of the anharmonic oscillator coupled to a purely diffusive environment. In both cases, these solutions are obtained by the application of the Baker-Campbell-Hausdorff (BCH) formulas to expand the evolution operator in an ordered product of exponentials. Moreover, we obtain an expression

Daisuke Nagai

We study the effects of galaxy formation on the Sunyaev-Zel&#39;dovich effect (SZE) observable-mass relations using high-resolution cosmological simulations. The simulations of eleven individual clusters spanning a decade in mass are performed with the shock-capturing Eulerian adaptive mesh refinement N-body+gasdynamics ART code. To assess the impact of gala

Aaron Bergman, Nicholas J. Proudfoot

Given a sufficiently nice collection of sheaves on an algebraic variety V, Bondal explained how to build a quiver Q along with an ideal of relations in the path algebra of Q such that the derived category of representations of Q subject to these relations is equivalent to the derived category of coherent sheaves on V. We consider the case in which these shea

Stefan Forcey, Felita Humes

It is well known that the existence of a braiding in a monoidal category V allows many structures to be built upon that foundation. These include a monoidal 2-category V-Cat of enriched categories and functors over V, a monoidal bicategory V-Mod of enriched categories and modules, a category of operads in V and a 2-fold monoidal category structure on V. We w

V. G. Gueorguiev, A. R. P. Rau, J. P. Draayer

The one-dimensional harmonic oscillator in a box problem is possibly the simplest example of a two-mode system. This system has two exactly solvable limits, the harmonic oscillator and a particle in a (one-dimensional) box. Each of the two limits has a characteristic spectral structure describing the two different excitation modes of the system. Near each of

Tao Liang, Thomas A. Witten

In this paper we report numerically observed spontaneous vanishing of mean curvature on a developable cone made by pushing a thin elastic sheet into a circular container. We show that this feature is independent of thickness of the sheet, the supporting radius and the amount of deflection. Several variants of developable cone are studied to examine the neces

Leonid Chuzhoy, Paul R. Shapiro

We present new analytic calculations of the coupling between ultraviolet resonance photons and the population of the hyperfine states in the light elements (H, D, He3+) which include several previously neglected physical processes. Among these are the backreaction of resonant scattering on the pumping radiation, the scattering of Ly_beta photons and the effe

Adam Massey, Steven J. Miller, John Sinsheimer

Consider the ensemble of real symmetric Toeplitz matrices, each independent entry an i.i.d. random variable chosen from a fixed probability distribution p of mean 0, variance 1, and finite higher moments. Previous investigations showed that the limiting spectral measure (the density of normalized eigenvalues) converges weakly and almost surely, independent o

Antonio Padilla

Exact holography for cosmological branes in an AdS-Schwarzschild bulk was first introduced in hep-th/0204218. We extend this notion to include all co-dimension one branes moving in non-trivial bulk spacetimes. We use a covariant approach, and show that the bulk Weyl tensor projected on to the brane can always be traded in for "holographic" energy-momentum on

Valter Moretti

Scalar BMS-invariant QFT defined on the causal boundary $\scri$ of an asymptotically flat spacetime is discussed. (a)(i) It is noticed that the natural $BMS$ invariant pure quasifree state $λ$ on $\cW(\scri)$, recently introduced by Dappiaggi, Moretti an Pinamonti, enjoys positivity of the self-adjoint generator of $u$-translations with respect to {\em every

J. J. Kavich, M. P. Warusawithana, J. W. Freeland, P. Ryan

Using polarized X-rays, we compare the electronic and magnetic properties of a La(2/3)Sr(1/3)MnO(3)(LSMO)/SrTiO(3)(STO) and a modified LSMO/LaMnO(3)(LMO)/STO interface. Using the technique of X-ray resonant magnetic scattering (XRMS), we can probe the interfaces of complicated layered structures and quantitatively model depth-dependent magnetic profiles as a

B. Altschul

We examine the radiative corrections to an extension of the standard model containing a Lorentz-violating axial vector parameter. At second order in this parameter, the photon self-energy is known to contain terms that violate gauge invariance. Previously, this has been treated as a pathology, but it is also possible to take the gauge noninvariant terms at f

Thomas Hambye, Babiker Hassanain, John March-Russell, Martin Schvellinger

We study the $ΔI = 1/2$ rule for kaon decays and the $B_K$ parameter for $K^0 - {\bar K}^0$ mixing in a dual 5-dimensional holographic QCD model. We perform, in the chiral limit, computations of the relevant four-point current-current correlators, which depend upon self-interactions among the 5D bulk fields. Spontaneous chiral symmetry breaking ($χ$SB) is re

M. R. Bridson, T. R. Riley

The filling length of an edge-circuit ηin the Cayley 2-complex of a finite presentation of a group is the least integer L such that there is a combinatorial null-homotopy of ηdown to a base point through loops of length at most L. We introduce similar notions in which the null-homotopy is not required to fix a basepoint, and in which the contracting loop is

A. R. Mkrtchyan, A. A. Saharian, V. V. Parazian

We investigate the coherent electron-positron pair creation by high-energy photons in a periodically deformed single crystal with a complex base. The formula for the corresponding differential cross-section is derived for an arbitrary deformation field. The conditions are specified under which the influence of the deformation is considerable. The case is con

V. P. Gusynin, S. G. Sharapov

The analytical expressions for both diagonal and off-diagonal ac and dc conductivities of graphene placed in an external magnetic field are derived. These conductivities exhibit rather unusual behavior as functions of frequency, chemical potential and applied field which is caused by the fact that the quasiparticle excitations in graphene are Dirac-like. One

NA59 Collaboration, A. Apyan, R. O. Avakian, B. Badelek

The processes of coherent bremsstrahlung (CB) and coherent pair production (CPP) based on aligned crystal targets have been studied in the energy range 20-170 GeV. The experimental arrangement allowed for measurements of single photon properties of these phenomena including their polarization dependences. This is significant as the theoretical description of

Felipe Canoura, Jose D. Edelstein, Leopoldo A. Pando Zayas, Alfonso V. Ramallo

We systematically study supersymmetric embeddings of D-brane probes of different dimensionality in the AdS_5xY^{p,q} background of type IIB string theory. The main technique employed is the kappa symmetry of the probe&#39;s worldvolume theory. In the case of D3-branes, we recover the known three-cycles dual to the dibaryonic operators of the gauge theory and

Ivan C. H. Liu, Jan M. Rost

We investigate properties of ultralong-range polyatomic molecules formed with a Rb Rydberg atom and several ground-state atoms whose distance from the Rydberg atom is of the order of n^2a_0, where n is the principle quantum number of the Rydberg electron. In particular, we put emphasis on the splitting of the energy levels, and elucidate the nature of the sp

Long-long Feng

Based on the Beylkin-Cramer summation rule, we introduce a new fast algorithm that enable us to explore the high order statistics efficiently in large data sets. Central to this technique is to make decomposition both of fields and operators within the framework of multi-resolution analysis (MRA), and realize theirs discrete representations. Accordingly, a h

Krzysztof Kulakowski

We consider ghetto as a community of people ruled against their will by an external power. Members of the community feel that their laws are broken. However, attempts to leave ghetto makes their situation worse. We discuss the relation of the ghetto inhabitants to the ruling power in context of their needs, organized according to the Maslow hierarchy. Decisi

Sergey Kovalenko, Ivan Schmidt

We demonstrate the existence of model independent one-to-one correspondence relations between different lepton flavor violating processes (LFV). Applying the criterion of naturalness, based on the idea of &#34;custodial symmetry&#34;, we show that all the LFV processes, independently of specific mechanisms behind them, but with the same external leptons, hav

Jing Chen

This paper consists of two parts. In the first part, we develop a new information theory, in which it is not a coincidence that information and physical entropy share the same mathematical formula. It is an adaptation of mind to help search for resources. We then show that psychological patterns either reflect the constraints of physical laws or are evolutio

R. Buras, H. -Th. Janka, M. Rampp, K. Kifonidis

1D and 2D supernova simulations for stars between 11 and 25 solar masses are presented, making use of the Prometheus/Vertex neutrino-hydrodynamics code, which employs a full spectral treatment of the neutrino transport. Multi-dimensional transport aspects are treated by the ``ray-by-ray plus&#39;&#39; approximation described in Paper I. Our set of models inc

Ansgar Gruene, Sanaz Kamali Sarvestani

Given S_1, a finite set of points in the plane, we define a sequence of point sets S_i as follows: With S_i already determined, let L_i be the set of all the line segments connecting pairs of points of the union of S_1,...,S_i, and let S_i+1 be the set of intersection points of those line segments in L_i, which cross but do not overlap. We show that with the

Domenico Orlando, P. Marios Petropoulos, Konstadinos Sfetsos

We analyze the behaviour of heterotic squashed-Wess-Zumino-Witten backgrounds under renormalization-group flow. The flows we consider are driven by perturbation creating extra gauge fluxes. We show how the conformal point acts as an attractor from both the target-space and world-sheet points of view. We also address the question of instabilities created by t

Shlomo Dado, Arnon Dar, A. De Rujula

The &#34;canonical behaviour&#34; of the early X-ray afterglows of long-duration Gamma-Ray Bursts (GRBs) --observed by the X-Ray Telescope of the SWIFT satellite-- is precisely the one predicted by the Cannonball model of GRBs.

Farrukh Mukhamedov, Utkir Rozikov, Jose Fernando F. Mendes

In the paper we considere three state $p$-adic Potts model with competing interactions on a Cayley tree of order two. We reduce a problem of describing of the $p$-adic Gibbs measures to the solution of certain recursive equation, and using it we will prove that a phase transition occurs if and only if $p=3$ for any value (non zero) of interactions. As well,

H. P. Blok L. Lapikás

The A-dependence of models for the attenuation of hadron production in semi-inclusive deep-inelastic scattering on a nucleus is investigated for realistic matter distributions. It is shown that the dependence for a pure partonic (absorption) mechanism is more complicated than a simple $A^{2/3}$ ($A^{1/3}$) behavior, commonly found when using rectangular or G

Claus Kiefer, Jakob Mueller-Hill, Cenalo Vaz

We extend the classical and quantum treatment of the Lemaitre-Tolman-Bondi (LTB) model to the non-marginal case (defined by the fact that the shells of the dust cloud start with a non-vanishing velocity at infinity). We present the classical canonical formalism and address with particular care the boundary terms in the action. We give the general relation be

M. Kormos

In this paper we investigate renormalisation group flows of supersymmetric minimal models generated by the boundary perturbing field (\hat G_{-1/2}ϕ_{1,3}). Performing the Truncated Conformal Space Approach analysis the emerging pattern of the flow structure is consistent with the theoretical expectations. According to the results, this pattern can be natura

E. Livanou, M. Kontizas, I. Gonidakis, E. Kontizas

Aims. Filamentary structures of early type stars are found to be a common feature of the Magellanic Clouds formed at an age of about 0.9-2*10^8 yr. As we go to younger ages these large structures appear fragmented and sooner or later form young clusters and associations. In the optical domain we have detected 56 such large structures of young objects, known

Alain Connes, Caterina Consani, Matilde Marcolli

We combine aspects of the theory of motives in algebraic geometry with noncommutative geometry and the classification of factors to obtain a cohomological interpretation of the spectral realization of zeros of $L$-functions. The analogue in characteristic zero of the action of the Frobenius on l-adic cohomology is the action of the scaling group on the cycli

D. J. Shepherd, T. Franz, R. F. Werner

We discuss the role of classical control in the context of reversible quantum cellular automata. Employing the structure theorem for quantum cellular automata, we give a general construction scheme to turn an arbitrary cellular automaton with external classical control into an autonomous one, thereby proving the computational equivalence of these two models.

Stefan Schroeer

I construct normal del Pezzo surfaces, and regular weak del Pezzo surfaces as well, with positive irregularity q>0. Such things can happen only over nonperfect fields. The surfaces in question are twisted forms of nonnormal del Pezzo surfaces, which were classified by Reid. The twisting is with respect to the flat topology and infinitesimal group scheme acti

O. Bertolami, J. G. Rosa

We discuss the implications of a model of noncommutative Quantum Mechanics where noncommutativity is extended to the phase space. We analyze how this model affects the problem of the two-dimensional gravitational quantum well and use the latest experimental results for the energy states of neutrons in the Earth&#39;s gravitational field to establish an upper

Peter L. Biermann, Paul H. Frampton

Assuming that there is no GZK (Greisen-Zatsepin-Kuzmin) cut-off and that super-GZK cosmic rays correlate with AGN (Active Galactic Nuclei) at cosmological distances, it is speculated that a relic superheavy particle (X) has its lifetime enhanced by sequestration in an extra dimension. This sequestration is assumed to be partially liberated by proximity of me

Gernot Schaller, Ralf Schützhold

We propose a probabilistic quantum algorithm that decides whether a monochrome picture matches a given template (or one out of a set of templates). As a major advantage to classical pattern recognition, the algorithm just requires a few incident photons and is thus suitable for very sensitive pictures (similar to the Elitzur-Vaidman problem). Furthermore, fo

Mayeul Arminjon

Starting from an interpretation of the classical-quantum correspondence, we derive the Dirac equation by factorizing the algebraic relation satisfied by the classical Hamiltonian, before applying the correspondence. This derivation applies in the same form to a free particle, to one in an electromagnetic field, and to one subjected to geodesic motion in a st

Ilian T. Iliev, Garrelt Mellema, Ue-Li Pen, Hugh Merz

We present the first large-scale radiative transfer simulations of cosmic reionization, in a simulation volume of (100/h Mpc)^3, while at the same time capturing the dwarf galaxies which are primarily responsible for reionization. We achieve this by combining the results from extremely large, cosmological, N-body simulations with a new, fast and efficient co

W. F. Thi, E. F. van Dishoeck, E. Dartois, K. M. Pontoppidan

We performed a spectroscopic survey toward five intermediate-mass class I YSOs located in the Southern Vela molecular cloud in the L and M bands at resolving powers 600-800 up to 10,000, using the Infrared Spectrometer and Array Camera mounted on the VLT-ANTU. Lower mass companion objects were observed simultaneously in both bands. Solid H2O at 3 micron is d

N. G. Antoniou, F. K. Diakonos, E. N. Saridakis, G. A. Tsolias

We investigate the classical evolution of a $ϕ^4$ scalar field theory, using in the initial state random field configurations possessing a fractal measure expressed by a non-integer mass dimension. These configurations resemble the equilibrium state of a critical scalar condensate. The measures of the initial fractal behavior vary in time following the mean

Paul A Crowther, L J Hadfield

New NTT/EMMI spectrophotometry of single WN2-5 stars in the Magellanic Clouds are presented, from which HeII 4686 line luminosities have been derived, and compared with observations of other Magellanic Cloud WR stars. SMC WN3-4 stars possess line luminosities which are a factor of 4 times lower than LMC counterparts, incorporating several binary SMC WN3-4 st

M. Takeuchi, T. Takano, S. Ichihara, Y. Takasu

We report observation of the paramagnetic Faraday rotation of spin-polarized ytterbium (Yb) atoms. As the atomic samples, we used an atomic beam, released atoms from a magneto-optical trap (MOT), and trapped atoms in a far-off-resonant trap (FORT). Since Yb is diamagnetic and includes a spin-1/2 isotope, it is an ideal sample for the spin physics, such as qu

Zhongzhi Zhang, Lili Rong, Shuigeng Zhou

We propose a general geometric growth model for pseudofractal scale-free web, which is controlled by two tunable parameters. We derive exactly the main characteristics of the networks: degree distribution, second moment of degree distribution, degree correlations, distribution of clustering coefficient, as well as the diameter, which are partially determined

F G Scholtz, H B Geyer

The Moyal product is used to cast the equation for the metric of a non-hermitian Hamiltonian in the form of a differential equation. For Hamiltonians of the form $p^2+V(ix)$ with $V$ polynomial this is an exact equation. Solving this equation in perturbation theory recovers known results. Explicit criteria for the hermiticity and positive definiteness of the

Jens Braun, Holger Gies

We analyze the running gauge coupling at finite temperature for QCD, using the functional renormalization group. The running of the coupling is calculated for all scales and temperatures. At finite temperature, the coupling is governed by a fixed point of the 3-dimensional theory for scales smaller than the corresponding temperature. The running coupling can

F. Ianni, D. Lasne, R. Sarcia, P. Hebraud

The reversible aggregates formation in a shear thickening, concentrated colloidal suspension is investigated through speckle visibility spectroscopy, a dynamic light scattering technique recently introduced [P.K. Dixon and D.J. Durian, Phys. Rev. Lett. 90, 184302 (2003)]. Formation of particles aggregates is observed in the jamming regime, and their relaxati

C. D. Fosco, J. Sanchez-Guillen, R. A. Vazquez

We construct a worldline path integral for the effective action and propagator of a Dirac field in 2+1 dimensions in an Abelian gauge field background. Integrating over an auxiliary gauge group variable we derive a worldline action depending only on $x(τ)$, the spacetime paths. We show that that action is a combination of a kinetic term plus a spin action. T

T. Eronen, V. Elomaa, U. Hager, J. Hakala

Masses of the radioactive isotopes 62Ga, 62Zn and 62Cu have been measured at the JYFLTRAP facility with a relative precision of better than 18 ppb. A Q_EC value of (9181.07 +- 0.54) keV for the superallowed decay of 62Ga is obtained from the measured cyclotron frequency ratios of 62Ga-62Zn, 62Ga-62Ni and 62Zn-62Ni ions. The resulting Ft-value supports the va

Klaus Reygers

Direct-photon measurements in p+p and Au+Au collisions at sqrt{s_{NN}} = 200 GeV from the PHENIX experiment are presented. The p+p results are found to be in good agreement with next-to-leading-order (NLO) perturbative QCD calculations. Direct-photon yields in Au+Au collisions scale with the number of inelastic nucleon-nucleon collisions and don't exhibit th

Davide Ceresoli, T. Thonhauser, David Vanderbilt, R. Resta

We derive a multi-band formulation of the orbital magnetization in a normal periodic insulator (i.e., one in which the Chern invariant, or in 2d the Chern number, vanishes). Following the approach used recently to develop the single-band formalism [T. Thonhauser, D. Ceresoli, D. Vanderbilt, and R. Resta, Phys. Rev. Lett. {\bf 95}, 137205 (2005)], we work in

Marcella Palese, Ekkehart Winterroth

Recently we found that canonical gauge-natural superpotentials are obtained as global sections of the {\em reduced} $(n-2)$-degree and $(2s-1)$-order quotient sheaf on the fibered manifold $\bY_{\zet} \times_{\bX} \mathfrak{K}$, where $\mathfrak{K}$ is an appropriate subbundle of the vector bundle of (prolongations of) infinitesimal right-invariant automorph

Enwei Liang, Bing Zhang

Several gamma-ray burst (GRB) luminosity indicators (LIs)have been proposed. Unlike SNe Ia, calibration of GRB LIs using a low-redshift sample is difficult. Based on the Bayesian theory, here we propose an approach to calibrate these LIs without introducing a low-redshift GRB sample. The essential points of our approach include, (1) calibrate the power-law i

A. Baykal, S. C. Inam, E. Beklen

We analyzed RXTE archival observations of 4U 1907+09 between 17 February 1996 and 6 March 2002. The pulse timing analysis showed that the source stayed at almost {\bf{constant}} period around August 1998 and then started to spin-down at a rate of $(-1.887\mp 0.042)\times 10^{-14}$ Hz s$^-1$ which is $\sim$ 0.60 times lower than the long term ($\sim 15$ years

Chris Lintott, Ignacio Ferreras, Ofer Lahav

In the context of recent observational results that show massive ellipticals were in place at high redshifts, we reassess the status of monolithic collapse in a LCDM universe. Using a sample of over 2000 galaxies from the Sloan Digital Sky Survey, by comparing the dynamical mass and stellar mass (estimated from colours) we find that ellipticals have `cores&#

P. Sunthar, J. Ravi Prakash

The hydrodynamic radius of a polymer chain, obtained using Brownian dynamics simulations of the continuum Edwards model, is found to obey a crossover in the excluded volume parameter z, which is significantly different from that observed for the radius of gyration. It is shown that this difference arises from contributions due to dynamic correlations to the

Masayuki Matsuo

We analyze spatial structure of the neutron Cooper pair in superfluid low-density uniform matter by means of BCS calculations employing a bare force and the effective Gogny interaction. It is shown that the Cooper pair exhibits a strong spatial di-neutron correlation in a wide range of neutron density $ρ/ρ_0\approx 10^{-4}-0.5$. This feature is related to th

Sergio Gaudio, B. Mihaila, K. B. Blagoev, K. S. Bedell

Dilute gas Bose-Einstein condensates (BEC&#39;s), currently used to cool fermionic atoms in atom traps, can also probe the superfluidity of these fermions. The damping rate of BEC-acoustic excitations (phonon modes), measured in the middle of the trap as a function of the phonon momentum, yields an unambiguous signature of BCS-like superfluidity, provides a

R. T. Thew, S. Tanzilli, L. Krainer, S. C. Zeller

We have developed a hybrid single photon detection scheme for telecom wavelengths based on nonlinear sum-frequency generation and silicon single-photon avalanche diodes (SPADs). The SPAD devices employed have been designed to have very narrow temporal response, i.e. low jitter, which we can exploit for increasing the allowable bit rate for quantum key distri