April 2007 arXiv papers — page 10

Jessica K. Barrett, George Savvidy

For non-Abelian tensor gauge fields of the lower rank we have found an alternative expression for the field strength tensors, which transform homogeneously with respect to the complementary gauge transformations and allow us to construct the dual Lagrangian.

Thomas Dedieu

Self-rational maps of generic algebraic K3 surfaces are conjectured to be trivial. We relate this conjecture to a conjecture concerning the irreducibility of the universal Severi varieties parametrizing nodal curves of given genus and degree lying on some K3 surface. We also establish a number of numerical constraints satisfied by such non trivial rational m

V. Urpin

We consider stability of differentially rotating non-magnetic proto-neutron stars. When neutrino transport is efficient, the star can be subject to a diffusive instability that can occur even in the convectively stable region. The instability arises on the time-scale comparable to the time-scale of thermal diffusion. Hydrodynamic motions driven by the instab

Rui Liu, Yinchang Li, Meiying Hou, Baruch Meerson

We show that the van der Waals-like phase separation instability of a driven granular gas at zero gravity, previously investigated in two-dimensional settings, persists in three dimensions. We consider a monodisperse granular gas driven by a thermal wall of a three-dimensional rectangular container at zero gravity. The basic steady state of this system, as d

Henny J. G. L. M. Lamers

The development and progress of the studies of winds and mass loss from hot stars, from about 1965 up to now, is discussed in a personal historical perspective. The present state of knowledge about stellar winds, based on papers presented at this workshop, is described. About ten years ago the mechanisms of the winds were reasonably well understood, the mass

J. D. McEwen, P. Vielva, Y. Wiaux, R. B. Barreiro

The cosmic microwave background (CMB) is a relic radiation of the Big Bang and as such it contains a wealth of cosmological information. Statistical analyses of the CMB, in conjunction with other cosmological observables, represent some of the most powerful techniques available to cosmologists for placing strong constraints on the cosmological parameters tha

Giorgio Terracina, Nicola Leone, Vincenzino Lio, Claudio Panetta

This paper considers the problem of reasoning on massive amounts of (possibly distributed) data. Presently, existing proposals show some limitations: {\em (i)} the quantity of data that can be handled contemporarily is limited, due to the fact that reasoning is generally carried out in main-memory; {\em (ii)} the interaction with external (and independent) D

Thierry de la Rue, Roberto Fernandez, Alan D. Sokal

Motivated by the Dobrushin uniqueness theorem in statistical mechanics, we consider the following situation: Let αbe a nonnegative matrix over a finite or countably infinite index set X, and define the "cleaning operators" β_h = I_{1-h} + I_h αfor h: X \to [0,1] (here I_f denotes the diagonal matrix with entries f). We ask: For which "cleaning se

Ch. Skokos, T. C. Bountis, Ch. Antonopoulos

We investigate the detailed dynamics of multidimensional Hamiltonian systems by studying the evolution of volume elements formed by unit deviation vectors about their orbits. The behavior of these volumes is strongly influenced by the regular or chaotic nature of the motion, the number of deviation vectors, their linear (in)dependence and the spectrum of Lya

I. S. Glass, F. van Leeuwen

Period-luminosity sequences have been shown to exist among the Semi-Regular Variables (SRVs) in the Magellanic Clouds (Wood et al, 1999), the Bulge of the Milky Way galaxy (Glass & Schultheis, 2003) and elsewhere. Using modern period and revised Hipparcos parallax data, this paper demonstrates that they also appear among the M-giant SRVs of the Solar Neighbo

P. Lesaffre, M. Gerin, P. Hennebelle

Aims. We probe the effect of turbulent diffusion on the chemistry at the interface between a cold neutral medium (CNM) cloudlet and the warm neutral medium (WNM). Methods. We perform moving grid, multifluid, 1D, hydrodynamical simulations with chemistry including thermal and chemical diffusion. The diffusion coefficients are enhanced to account for turbulent

Boldizsar Kalmar

We show that the cobordism groups of negative codimensional folds maps contain direct sums of stable homotopy groups of Thom spaces of vector bundles like the circle and the infinite dimensional projective space. We give geometrical invariants which detect these direct summands.

Y. Wiaux, J. D. McEwen, P. Vielva

In the general context of complex data processing, this paper reviews a recent practical approach to the continuous wavelet formalism on the sphere. This formalism notably yields a correspondence principle which relates wavelets on the plane and on the sphere. Two fast algorithms are also presented for the analysis of signals on the sphere with steerable wav

Udo Schwingenschloegl, Cosima Schuster

Charge redistribution at interfaces is crucial for electronic applications of high-Tc superconductors, since the band structure is modified on a local scale. We address the normal-state electronic structure of YBa2Cu3O7 (YBCO) at an YBCO-metal contact by first principles calculations for prototypical interface configurations. We derive quantitative results f

Evgueni Petrov

We describe an algorithm for evaluation of the interval extension of the power function of variables x and y given by the expression x^y. Our algorithm reduces the general case to the case of non-negative bases.

Farook Rahaman

The gravitational field of both local and global non static cosmic strings in the context of Lyra geometry are investigated. Local strings are characterized by having an energy momentum tensor whose only non null components are $T_{tt} = T_{zz}$ . As linearized Einstein equations are formally analogous to the Maxwell equations, the exterior solution does not

M. Volk, S. Whitlock, B. V. Hall, A. I. Sidorov

Surface based geometries of microfabricated wires or patterned magnetic films can be used to magnetically trap and manipulate ultracold neutral atoms or Bose-Einstein condensates. We investigate the magnetic properties of such atom chips using a scanning magnetoresistive (MR) microscope with high spatial resolution and high field sensitivity. We show that MR

F. Rahaman, S. Mal, P. Ghosh

A class of exact static solution around a global monopole resulting from the breaking of a global S0(3) symmetry is obtained in the context of Lyra geometry. Our solution is shown to possess an interesting feature like wormholes space-time. It has been shown that the global monopole exerts no gravitational force on surrounding non-relativistic matter.

The HERMES Collaboration, A. Airapetian

The HERMES experiment has measured the transverse polarization of Lambda and Lambda-bar hyperons produced inclusively in quasireal photoproduction at a positron beam energy of 27.6 GeV. The transverse polarization of the Lambda hyperon is found to be positive while the observed Lambda-bar polarization is compatible with zero. The transverse polarization valu

X. -H. Guo, Z. -H. Zhang

We study the direct CP violation in $\bar{B}^0 \to ρ^0(ω)ρ^0(ω) \to π^+π^-π^+π^-$ (with unpolarized $ρ^0(ω)$) via the $ρ-ω$ mixing mechanism which causes a large strong phase difference and consequently a large CP violating asymmetry when the masses of the $π^+π^-$ pairs are in the vicinity of the $ω$ resonance. Since there are two $ρ(ω)$ mesons in the inter

J. M. Diego, D. Herranz

In this paper we study the possibility of detecting lensing signals in high-resolution and high-sensitivity CMB experiments. At scales below 1 arcmin, the CMB background is dominated by the Sunyaev-Zel'dovich effect in clusters and by Ostriker-Vishniac effect distortions elsewhere. Assuming the Sunyaev-Zel'dovich component in clusters can be removed,

Luigi Martina, Giulio Soliani

The relation between the correlation energy and the entanglement is analytically constructed for the Moshinsky's model of two coupled harmonic oscillators. It turns out that the two quantities are far to be proportional, even at very small couplings. A comparison is made also with the 2-point Ising model.

Li-Xin Li

Because of the limit in the number of gamma-ray bursts (GRBs) with available redshifts and spectra, all current investigations on the correlation among GRB variables use burst samples with redshifts that span a very large range. The evolution and selection effects have thus been ignored, which might have important influence on the results. In this Letter, we

Alberto Elduque, Oliver Villa

Superinvolutions on graded associative algebras constitute a source of Lie and Jordan superalgebras. Graded versions of the classical Albert and Albert-Riehm Theorems on the existence of superinvolutions are proven. Surprisingly, the existence of superinvolutions of the first kind is a rare phenomenon, as nontrivial central division superalgebras are never e

T. Yokoyama, Y. Sawa, Y. Tanaka, A. A. Golubov

We study theoretically the Josephson effect in d-wave superconductor / diffusive normal metal /insulator/ diffusive normal metal/ d-wave superconductor (D/DN/I/DN/D) junctions. This model is aimed to describe practical junctions in high-$T_C$ cuprate superconductors, in which the product of the critical Josephson current ($I_C$) and the normal state resistan

T. Yokoyama, Y. Tanaka

We study tunneling conductance in normal metal / insulator / ferromagnetic superconductor junctions. The tunneling spectra show a clear difference between spin-singlet s-wave pairing, spin-triplet opposite spin pairing and spin-triplet equal spin pairing: These pairings exhibit, respectively, gap struture, double peak structure and zero bias peak in the spec

Filippo Cagnetti, Maria Giovanna Mora, Massimiliano Morini

A new necessary minimality condition for the Mumford-Shah functional is derived by means of second order variations. It is expressed in terms of a sign condition for a nonlocal quadratic form on $H^1_0(Γ)$, $Γ$ being a submanifold of the regular part of the discontinuity set of the critical point. Two equivalent formulations are provided: one in terms of the

I. Area, M. K. Atakishiyeva, J. Rodal

We prove that a customary Sturm-Liouville form of second-order $q$-difference equation for the continuous $q$-ultraspherical polynomials $C_n(x;β| q)$ of Rogers can be written in a factorized form in terms of some explicitly defined $q$-difference operator ${\mathcal D}_x^{β, q}$. This reveals the fact that the continuous $q$-ultraspherical polynomials $C_n(

Jean Bertoin

We show that for $0<α<1$ and $θ>-α$, the Poisson-Dirichlet distribution with parameter $(α, θ)$ is the unique reversible distribution of a rather natural fragmentation-coalescence process. This completes earlier results in the literature for certain split and merge transformations and the parameter $α=0$.

Oliver Henkel

A new class of space time codes with high performance is presented. The code design utilizes tailor-made permutation codes, which are known to have large minimal distances as spherical codes. A geometric connection between spherical and space time codes has been used to translate them into the final space time codes. Simulations demonstrate that the performa

S Ole Warnaar

In a recent paper Flohr, Grabow and Koehn conjectured that the characters of the logarithmic conformal field theory c_{k,1}, of central charge c=1-6(k-1)^2/k, admit fermionic representations labelled by the Lie algebra D_k. In this note we provide a simple analytic proof of this conjecture.

M. W. J. Bromley, J. Mitroy, K. Varga

The structure of the unnatural parity states of PsH, LiPs, NaPs and KPs are investigated with the configuration interaction and stochastic variational methods. The binding energies (in hartree) are found to be 8.17x10-4, 4.42x10-4, 15.14x10-4 and 21.80x10-4 respectively. These states are constructed by first coupling the two electrons into a configuration wh

P. Blasiak, A. Horzela, K. A. Penson, A. I. Solomon

We discuss a general combinatorial framework for operator ordering problems by applying it to the normal ordering of the powers and exponential of the boson number operator. The solution of the problem is given in terms of Bell and Stirling numbers enumerating partitions of a set. This framework reveals several inherent relations between ordering problems an

T. O. Wehling, H. P. Dahal, A. I. Lichtenstein, A. V. Balatsky

We study the effect of impurities in superconducting graphene and discuss their influence on the local electronic properties. In particular, we consider the case of magnetic and non-magnetic impurities being either strongly localized or acting as a potential averaged over one unit cell. The spin dependent local density of states is calculated and possibiliti

Rafe Mazzeo, Mariel Saez

We prove the existence of self-similar expanding solutions of the curvature flow on planar networks where the initial configuration is any number of half-lines meeting at the origin. This generalizes recent work by Schnürer and Schulze which treats the case of three half-lines. There are multiple solutions, and these are parametrized by combinatorial objects

Emppu Salonen, Emma Terama, Ilpo Vattulainen, Mikko Karttunen

We investigate the dielectrophoretic motion of charge-neutral, polarizable nanocolloids through molecular dynamics simulations. Comparison to analytical results derived for continuum systems shows that the discrete charge distributions on the nanocolloids have a significant impact on their coupling to the external field. Aggregation of nanocolloids leads to

Y. W. Li, D. Qian, L. Wray, D. Hsieh

Momentum resolved inelastic resonant x-ray scattering is used to map the evolution of charge excitations over a large range of energies, momenta and doping levels in the electron doped Mott insulator class Nd$_{2-x}$Ce$_x$CuO$_4$. As the doping induced AFM-SC (antiferromagnetic-superconducting) transition is approached, we observe an anisotropic softening of

Irene M. Gamba, Maria Pia Gualdani, Ping Zhang

The blow-up in finite time for the solutions to the initial-boundary value problem associated to the multi-dimensional quantum hydrodynamic model in a bounded domain is proved. The model consists on conservation of mass equation and a momentum balance equation equivalent to a compressible Euler equations corrected by a dispersion term of the third order in t

Youichi Shibukawa

By means of left quasigroups L=(L, .) and ternary systems, we construct dynamical Yang-Baxter maps associated with L, L, and (.) satisfying an invariance condition that the binary operation (.) of the left quasigroup L defines. Conversely, this construction characterize such dynamical Yang-Baxter maps. The unitary condition of the dynamical Yang-Baxter map i

T. S. Bastian

An interplanetary (IP) type-II-like radio burst is analyzed. It occurred on 2003 June 17-18 in association with a fast halo coronal mass ejection (CME), an M6.8 soft-X-ray (SXR) flare, and produced a solar proton event. Unlike coronal type II bursts and the ma jority of IP type II radio emissions, the IP type-II-like event associated with the fast halo CME o

Keivan G. Stassun, Robert D. Mathieu, Jeff A. Valenti

The newly discovered brown-dwarf eclipsing binary 2MASS J05352184-0546085 provides a unique laboratory for testing the predictions of theoretical models of brown-dwarf formation and evolution. The finding that the lower-mass brown dwarf in this system is hotter than its higher-mass companion represents a challenge to brown-dwarf evolutionary models, none of

Wako Aoki, Satoshi Honda, Kozo Sadakane, Nobuo Arimoto

The Thorium abundance for the red giant COS82 in the Ursa Minor dwarf spheroidal galaxy is determined based on a high resolution spectrum. This is the first detection of actinides in an extra Galactic object. A detailed abundance pattern is determined for 12 other neutron-capture elements from the atomic number 39 to 68. These elements are significantly over

Seung-il Nam, Ki-Seok Choi, Atsushi Hosaka, Hyun-Chul Kim

We study a new nucleon resonance from eta photoproduction, which was observed at sqrt{s}=1675 MeV with a narrow decay width (~10 MeV) by the Tohoku LNS group as well as the GRAAL collaboration. Using an effective Lagrangian approach, we compute differential cross sections for the eta photoproduction. In addition to N*(1675,1/2+-,3/2+-), we employ six other n

S. Brough, R. Proctor, D. Forbes, W. Couch

We present an examination of the kinematics and stellar populations of a sample of 3 Brightest Group Galaxies (BGGs) and 3 Brightest Cluster Galaxies (BCGs) in X-ray groups and clusters. We have obtained high signal-to-noise Gemini/GMOS (Gemini South Multi-Object Spectrograph) long-slit spectra of these galaxies and use Lick indices to determine ages, metall

David A. Richter

This note gives an explicit formula for the elements of the E(8) root system. The formula is triacontagonally symmetric in that one may clearly see an action by the cyclic group with 30 elements. The existence of such a formula is due to the fact that the Coxeter number of E(8) is 30.

Andrea V. Maccio&#39;, Ioannis Sideris, Marco Miranda, Ben Moore

It has been shown that the dissipative gas infall during galaxy formation has the capability to modify the shape of dark matter halos. In this paper we perform the first detailed analysis of particle orbits in a cosmological dark matter halos to understand {\it how} and {\it why} baryons alter its shape. We perform a series of numerical experiments where we

Sydney A. Barnes

We here develop an improved way of using a rotating star as a clock, set it using the Sun, and demonstrate that it keeps time well. This technique, called gyrochronology, permits the derivation of ages for solar- and late-type main sequence stars using only their rotation periods and colors. The technique is clarified and developed here, and used to derive a

N. Mirabal, J. P. Halpern, P. T. O&#39;Brien

We present the optical identification and spectroscopy of the host galaxy of GRB 050826 at a redshift z = 0.296 +/- 0.001. Image subtraction among observations obtained on three consecutive nights, reveals a fading object 5 hours after the burst, confirming its identification as the optical afterglow of this event. Deep imaging shows that the optical aftergl

Kyle Lawson, Ariel R. Zhitnitsky

Several independent observations of the galactic core suggest hitherto unexplained sources of energy. The most well known case is the 511 keV line which has proven very difficult to explain with conventional astrophysical positron sources. A similar, but less well known mystery is the excess of gamma-ray photons detected by COMPTEL across a broad energy rang

Jean-Baptiste Meilhan, Akira Yasuhara

We consider the operation of Whitehead double on a component of a link and study the behavior of Milnor invariants under this operation. We show that this operation turns a link whose Milnor invariants of length < k are all zero into a link with vanishing Milnor invariants of length < 2k, and we provide formulas for the first non-vanishing ones. As a consequ

David P. Blecher, Maureen K. Royce

We transcribe a portion of the theory of extensions of C*-algebras to general operator algebras. We also include several new general facts about approximately unital ideals in operator algebras and the C*-algebras which they generate.

H. A. Dye

Two virtual link diagrams are homotopic if one may be transformed into the other by a sequence of virtual Reidemeister moves, classical Reidemeister moves, and self crossing changes. We recall the pure virtual braid group. We then describe the set of pure virtual braids that are homotopic to the identity braid.

Mihai Bailesteanu, Vlad Balan, Dierk Schleicher

We investigate the set $I$ of parameters $κ$ for which the singular value of $z\mapsto e^z+κ$ converges to $\infty$. The set $I$ consists of uncountably many parameter rays, plus landing points of some of these rays. We show that the parameter rays have Hausdorff dimension 1, while the ray endpoints in $I$ alone have dimension 2. Analogous results were known

Marek Biskup, Herbert Spohn

We consider gradient fields $(ϕ_x:x\in \mathbb{Z}^d)$ whose law takes the Gibbs--Boltzmann form $Z^{-1}\exp\{-\sum_{< x,y>}V(ϕ_y-ϕ_x)\}$, where the sum runs over nearest neighbors. We assume that the potential $V$ admits the representation \[V(η):=-\log\int\varrho({d}κ)\exp\biggl[-{1/2}κ\et a^2\biggr],\] where $\varrho$ is a positive measure with compact sup

P. Bozhilov

It is known that large class of classical string solutions in the type IIB AdS_5xS^5 background is related to the Neumann and Neumann-Rosochatius integrable systems, including spiky strings and giant magnons. It is also interesting if these integrable systems can be associated with some membrane configurations in M-theory. We show here that this is indeed th

Ole Host, Steen H Hansen

Numerous ongoing experiments aim at detecting WIMP dark matter particles from the galactic halo directly through WIMP-nucleon interactions. Once such a detection is established a confirmation of the galactic origin of the signal is needed. This requires a direction-sensitive detector. We show that such a detector can measure the velocity anisotropy beta of t

M. Crocce, R. Scoccimarro

We study the nonlinear evolution of the baryon acoustic oscillations (BAO) in the dark matter power spectrum and correlation function using renormalized perturbation theory (RPT). In a previous paper we showed that RPT successfully predicts the damping of acoustic oscillations; here we extend our calculation to the enhancement of power due to mode-coupling.

A. Perrin, H. Chang, V. Krachmalnicoff, M. Schellekens

We study atom scattering from two colliding Bose-Einstein condensates using a position sensitive, time resolved, single atom detector. In analogy to quantum optics, the process can also be thought of as spontaneous, degenerate four wave mixing of de Broglie waves. We find a clear correlation between atoms with opposite momenta, demonstrating pair production

L. Scheck, H. -Th. Janka, T. Foglizzo, K. Kifonidis

By 2D hydrodynamic simulations including a detailed equation of state and neutrino transport, we investigate the interplay between different non-radial hydrodynamic instabilities that play a role during the postbounce accretion phase of collapsing stellar cores. The convective mode of instability, which is driven by negative entropy gradients caused by neutr

Ya. Azimov, K. Goeke, I. Strakovsky

To understand the whole set of positive and null data on the Theta+(1530)-production, we suggest the hypothesis that multiquark hadrons are mainly generated from many-quark states, which emerge either as short-term hadron fluctuations, or as hadron remnants in hard processes. This approach allows us to describe both non-observation of the Theta+ in current n

Ari Pakman, Amit Sever

We extend to chiral N=4 operators the holographic agreement recently found between correlators of the symmetric orbifold of M^4 at large N and type IIB strings propagating in AdS(3) x S^3 x M^4, where M^4=T^4 or K3. We also present expressions for some bulk correlators not yet computed in the boundary.

Kerry M. Soileau

We find an arc-parameterization of the contour on which an given analytic function has constant modulus. This contour is seen to satisfy a differential equation which we explicitly give.

Aditya Ramamoorthy

This work considers the problem of transmitting multiple compressible sources over a network at minimum cost. The aim is to find the optimal rates at which the sources should be compressed and the network flows using which they should be transmitted so that the cost of the transmission is minimal. We consider networks with capacity constraints and linear cos

Fumihiro Takayama

We discuss the impact of charged massive particle big bang nucleosynthesis(CBBN) to explore the nature of the reheating of the Universe in the case that a new extremely long-lived charged massive particle(CHAMP) exists. If the mass of the CHAMP is within collider reach and it&#39;s lifetime is longer than $10^4$sec, the comparison between the CBBN prediction

A. Sesana, F. Haardt, P. Madau

Hypervelocity stars (HVSs) are a natural consequence of the presence of a massive nuclear black hole (Sgr A*) in the Galactic Center. Here we use the Brown et al. sample of unbound and bound HVSs together with numerical simulations of the propagation of HVSs in the Milky Way halo to constrain three plausible ejection mechanisms: 1) the scattering of stars bo

G. Hagen, T. Papenbrock, D. J. Dean, A. Schwenk

We derive coupled-cluster equations for three-body Hamiltonians. The equations for the one- and two-body cluster amplitudes are presented in a factorized form that leads to an efficient numerical implementation. We employ low-momentum two- and three-nucleon interactions and calculate the binding energy of He-4. The results show that the main contribution of

V. Nefer Senoguz

Assuming the Dirac-type neutrino masses m_D are related to quark or charged lepton masses, neutrino oscillation data indicate that right handed neutrino masses are in general strongly hierarchical. In particular, if m_D is similar to the up-type quark masses, the mass of the lightest right handed neutrino M_1<~10^6 GeV. We show that non-thermal leptogenesis

Vladimir Al. Osipov, Eugene Kanzieper

Motivated by the ongoing discussion about a seeming asymmetry in the performance of fermionic and bosonic replicas, we present an exact, nonperturbative approach to zero-dimensional replica field theories belonging to the broadly interpreted &#34;beta=2&#34; Dyson symmetry class. We then utilise the formalism developed to demonstrate that the bosonic replica

Alessandro Mirizzi, Georg G. Raffelt, Pasquale D. Serpico

One interpretation of the unexplained signature observed in the PVLAS experiment invokes a new axion-like particle (ALP) with a two-photon vertex, allowing for photon-ALP oscillations in the presence of magnetic fields. In the range of masses and couplings suggested by PVLAS, the same effect would lead to a peculiar dimming of high-energy photon sources. For

W. G. Kang, Y. D. Kim, J. I. Lee, I. S. Hahn

We have measured the thermal neutron capture cross section for w-180 nucleus. There is only one previous data on this cross section with a value of 30 $^{+300%}_{-100%}$ barn. To consider w-181 as a low energy neutrino source, the thermal neutron capture cross section should be measured more precisely to estimate the production rate of w-181 inside a nuclear

D. Bulacu, S. Caenepeel, B. Torrecillas

We introduce and investigate the basic properties of an involutory (dual) quasi-Hopf algebra. We also study the representations of an involutory quasi-Hopf algebra and prove that an involutory dual quasi-Hopf algebra with non-zero integral is cosemisimple.

Nenad Manojlovic, Zoltan Nagy

We implement the Bethe anstaz method for the elliptic quantum group $E_{τ,η}(A_2^{(2)})$. The Bethe creation operators are constructed as polynomials of the Lax matrix elements expressed through a recurrence relation. We also give the eigenvalues of the family of commuting transfer matrices defined in the tensor product of fundamental representations.

Simon J. E. Radford, Riccardo Giovanelli, Thomas A. Sebring, Jonas Zmuidzinas

Cornell University, the California Institute for Technology, and the Jet Propulsion Laboratory are jointly studying the construction of a 25 m diameter telescope for submillimeter astronomy on a high mountain in northern Chile. This Cornell Caltech Atacama Telescope (CCAT) will combine high sensitivity, a wide field of view, and a broad wavelength range to p

Mario Bessa, Joao Lopes Dias

We study the dynamical behaviour of Hamiltonian flows defined on 4-dimensional compact symplectic manifolds. We find the existence of a C2-residual set of Hamiltonians for which every regular energy surface is either Anosov or it is in the closure of energy surfaces with zero Lyapunov exponents a.e. This is in the spirit of the Bochi-Mane dichotomy for area-

S. Ishiwata, I. Terasaki, F. Ishii, N. Nagaosa

A two-staged, uniaxial magnetoresistive effect has been discovered in SrCo6O11 having a layered hexagonal structure. Conduction electrons and localized Ising spins are in different sublattices but their interpenetration makes the conduction electrons sensitively pick up the stepwise field-dependence of magnetization. The stepwise field-dependence suggests tw

Heiner Olbermann

We construct a new class of physical states of the free Klein-Gordon field in Robertson-Walker spacetimes. This is done by minimizing the expectation value of smeared stress-energy. We get an explicit expression for the state depending on the smearing function. We call it a state of low energy. States of low energy are an improvement of the concept of adiaba

A. Faggionato

We consider a stationary and ergodic random field {ω(b)} parameterized by the family of bonds b in Z^d, d>1. The random variable ω(b) is thought of as the conductance of bond b and it ranges in a finite interval [0,c_0]. Assuming that the set of bonds with positive conductance has a unique infinite cluster C, we prove homogenization results for the random wa

I. E. Batov, Th. Schapers, N. M. Chtchelkatchev, H. Hardtdegen

We study the magnetotransport in small hybrid junctions formed by high-mobility GaInAs/InP heterostructures coupled to superconducting (S) and normal metal (N) terminals. Highly transmissive superconducting contacts to a two-dimensional electron gas (2DEG) located in a GaInAs/InP heterostructure are realized by using a Au/NbN layer system. The magnetoresista

Lionel Bureau

We describe a surface force apparatus designed to probe the rheology of a nanoconfined medium under large shear amplitudes (up to 500 $μ$m). The instrument can be operated in closed-loop, controlling either the applied normal load or the thickness of the medium during shear experiments. Feedback control allows to greatly extend the range of confinement/shear

Avraham Schiller, Alessandro Silva

Transport properties of ultrasmall quantum dots with a single unpaired electron are commonly modeled by the nonequilibrium Kondo model, describing the exchange interaction of a spin-1/2 local moment with two leads of noninteracting electrons. Remarkably, the model possesses an exact solution when tuned to a special manifold in its parameter space known as th

J. Kluson, Kamal L. Panigrahi

We study properties of non-BPS D(p+1)-brane in the background of k NS5-branes, with one transverse direction compactified on a circle, from the point of view of Dirac-Born-Infeld action. We present the analysis of two different embedding of non-BPS D(p+1)-brane in given background and study the classical solutions of given world-volume theory. We argue for t

Pierre Schapira

We study modules over the algebroid stack $\W[\stx]$ of deformation quantization on a complex symplectic manifold $\stx$ and recall some results: construction of an algebra for $\star$-products, existence of (twisted) simple modules along smooth Lagrangian submanifolds, perversity of the complex of solutions for regular holonomic $\W[\stx]$-modules, finitene

Kieran Kelly, Przemysław Repetowicz, Seosamh macRéamoinn

Traditionally, it is understood that fluctuations in the equilibrium distribution are not evident in thermodynamic systems of large $N$ (the number of particles in the system) \cite{Huang1}. In this paper we examine the validity of this perception by investigating whether such fluctuations can in reality depend on temperature. Firstly, we describe fluctuatio

R. Thomas, T. Hilger, B. Kampfer

The in-medium behavior of the nucleon spectral density including self-energies is revisited within the framework of QCD sum rules. Special emphasis is given to the density dependence of four-quark condensates. A complete catalog of four-quark condensates is presented and relations among them are derived. Generic differences of such four-quark condensates occ

James G. Gilson

In this paper, it is shown that the cosmological model that was introduced in a sequence of three earlier papers under the title, A Dust Universe Solution to the Dark Energy Problem, can be used to resolve the problem of the great mismatch of numerical values between dark energy from cosmology and zero point energy from quantum theory. It is shown that, if t

Daniel Barlet

The concept of (a,b)-module comes from the study the Gauss-Manin lattices of an isolated singularity of a germ of an holomorphic function. It is a very simple &#39;&#39;abstract algebraic structure&#39;&#39;, but very rich, whose prototype is the formal completion of the Brieskorn-module of an isolated singularity. The aim of this article is to prove a very

R. Bluhm

A brief summary is presented of recent work examining the fate of the Nambu-Goldstone modes in gravitational theories with spontaneous Lorentz violation.

Yi Xie, Wei-Tou Ni, Peng Dong, Tian-Yi Huang

Deep space laser ranging missions like ASTROD I (Single-Spacecraft Astrodynamical Space Test of Relativity using Optical Devices) and ASTROD, together with astrometry missions like GAIA and LATOR will be able to test relativistic gravity to an unprecedented level of accuracy. More precisely, these missions will enable us to test relativistic gravity to $10^{

Mark Agranovsky

Let $Ω$ be a smooth real analytic submanifold of a complex manifold $X$. We establish and study the link between the following 3 subjects: 1) topological properties of smooth families of attached analytic discs, the manifold $Ω$ admits, 2) lower bounds for dimensions of complex tangent spaces of $Ω$, 3) a generalization of the argument principle for smooth f

Giancarlo Cella, Carlo Nicola Colacino, Elena Cuoco, Angela Di Virgilio

We consider the question of cross-correlation measurements using Virgo and the LSC Interferometers (LIGO Livingston, LIGO Hanford, and GEO600) to search for a stochastic gravitational-wave background. We find that inclusion of Virgo into the network will substantially improve the sensitivity to correlations above 200 Hz if all detectors are operating at thei

Guowu Meng

For each integer $n\ge 2$, we demonstrate that a 2n-dimensional generalized MICZ-Kepler problem has an $\widetilde{\mr{Spin}}(2, 2n+1)$ dynamical symmetry which extends the manifest $\mr{Spin}(2n)$ symmetry. The Hilbert space of bound states is shown to form a unitary highest weight $\widetilde{\mr{Spin}}(2, 2n+1)$-module which occurs at the first reduction

Serhiy E. Samokhvalov

We show that finite parallel transports of vectors in Riemannian spaces, determined by the multiplication law in the deformed groups of diffeomorphisms, and sequences of infinitesimal parallel transports of vectors along geodesics are equivalent.

Ahmadreza Azimifard

Let $UC(K)$ denote the Banach space of all bounded uniformly continuous functions on a hypergroup $K$. The main results of this article concern on the $α$-amenability of $UC(K)$ and quotients and products of hypergroups. It is also shown that a Sturm-Liouville hypergroup with a positive index is $α$-amenable if and only if $α=1$.

Kostya Trachenko

We propose that the origin of the Vogel-Fulcher-Tammann law is the increase of the range of elastic interaction between local relaxation events in a liquid. In this picture, we discuss the origin of cooperativity of relaxation, the absence of divergence of relaxation time at a finite temperature and the crossover to a more Arrhenius behaviour at low temperat

Yang Xiang, Shi-Jie Xiong

The entanglement fidelity provides a measure of how well the entanglement between two subsystems is preserved in a quantum process. By using a simple model we show that in some cases this quantity in its original definition fails in the measurement of the entanglement preserving. On the contrary, the modified entanglement fidelity, obtained by using a proper

M. J. Middleton, C. Done, M. Gierlinski

(abridged) The soft excess seen in the X-ray spectra of many high mass accretion rate AGN can be well modelled by reflection from a partially ionised accretion disc. However, the derived parameters are often extreme, both in terms of the underlying spacetime and the reflection geometry, and these models require that the disc is far from hydrostatic equilibri

V. I. Korobov, Ts. Tsogbayar

Effective potentials of the relativistic mα^6 order correction for the ground state of the Coulomb two-center problem are calculated. They can be used to evaluate the relativistic contribution of that order to the energies of hydrogen molecular ions or metastable states of the antiprotonic helium atom, where precision spectroscopic data are available. In our

Stephen Brierley, Atsushi Higuchi

We show that the state with the highest known average two-particle von Neumann entanglement entropy proposed by Sudbery and one of the authors gives a local maximum of this entropy. We also show that this is not the case for an alternative highly entangled state proposed by Brown et al.

N. Ishibashi, A. Yamaguchi

We construct a string field theory for c=1 noncritical strings using the loop variables as the string field. We show how one can express the nonrelativistic free fermions which describes the theory, in terms of these string fields.

Hui Zhai, Tin-Lun Ho

We study a quantum phase transition between fermion superfluid (SF) and band insulator (BI) of fermions in optical lattices. The destruction of the band insulator is driven by the energy gain in promoting fermions from valance band to various conducting bands to form Cooper pairs. We show that the transition must take place in rather shallow lattice height,