June 2007 arXiv papers — page 37

Etera R. Livine, Daniel R. Terno

In the framework of loop quantum gravity (LQG), having quantum black holes in mind, we generalize the previous boundary state counting (gr-qc/0508085) to a full bulk state counting. After a suitable gauge fixing we are able to compute the bulk entropy of a bounded region (the "black hole") with fixed boundary. This allows us to study the relationship

Satendra Pal Singh, Akhilesh Kumar Singh, Dhananjai Pandey, S. M. Yusuf

Dielectric measurements on 0.65[Pb(Ni_1/3Nb_2/3)O_3]-0.35PbTiO_3 ceramic in the temperature range 90K to 470K shows a relaxor ferroelectric transition around 350K with a Vogel-Fulcher freezing temperature of 338K and appearance of a non-ergodic relaxor ferroelectric phase of tetragonal structure at room temperature. This non-ergodic phase reenters into the r

Pascal M. Vaudrevange, Lev Kofman

The ``trans-Planckian'' challenge in cosmology appears when we trace the present physical wavelengths of fluctuations backwards in time. They become smaller and smaller until crossing the Planck scale where conventional QFT is challenged, so that unknown ultraviolet physics may be traced in the observable cosmological fluctuations. Usually this issue

Olaf Lechtenfeld, Alexander D. Popov, Richard J. Szabo

We construct explicit BPS and non-BPS solutions of the Yang-Mills equations on noncommutative spaces R^{2n}_theta x G/H which are manifestly G-symmetric. Given a G-representation, by twisting with a particular bundle over G/H, we obtain a G-equivariant U(k) bundle with a G-equivariant connection over R^{2n}_theta x G/H. The U(k) Donaldson-Uhlenbeck-Yau equat

D. Sands, J. Dunning-Davies

Some of the more powerful results of mathematical statistics are becoming of increasing importance in statistical mechanics. Here the use of the central limit theorem in conjunction with the canonical ensemble is shown to lead to an interesting and important new insight into results associated with the canonical ensemble. This theoretical work is illustrated

J. Ellis, S. Heinemeyer, K. A. Olive, G. Weiglein

The region of MSSM Higgs parameter space currently excluded by the CDF Collaboration, based on an analysis of ~1 fb^-1 of integrated luminosity, is less than the expected sensitivity. We analyze the potential implications of the persistence of this discrepancy within the MSSM, assuming that the soft supersymmetry-breaking contributions to scalar masses are u

Adele Nasti, Gabriele Travaglini

We discuss the calculation of one-loop amplitudes in N=8 supergravity using MHV diagrams. In contrast to MHV amplitudes of gluons in Yang-Mills, tree-level MHV amplitudes of gravitons are not holomorphic in the spinor variables. In order to extend these amplitudes off shell, and use them as vertices to build loops, we introduce certain shifts for the spinor

Hélène Esnault, Chenyang Xu

If the $\ell$-adic cohomology of a projective smooth variety, defined over a local field $K$ with finite residue field $k$, is supported in codimension $\ge 1$, then every model over the ring of integers of $K$ has a $k$-rational point. For $K$ a $p$-adic field, this is math/0405318, Theorem 1.1. If the model $\sX$ is regular, one has a congruence $|\sX(k)|\

Valeriu Moldoveanu, Vidar Gudmundsson, Andrei Manolescu

We present a theoretical study of the electronic transport through a many-level quantum dot driven by time-dependent signals applied at the contacts to the leads. If the barriers oscillate out of phase the system operates like a turnstile pump under a finite constant bias, as observed in the experiments of Kouwenhoven {\it et al.} [Phys. Rev. Lett. {\bf 67},

Hiroyuki Sagawa, Satoshi Yoshida, Guo-Mo Zeng, Jian-Zhong Gu

The isospin dependence of incompressibility is investigated in the Skyrme Hartree-Fock (SHF) and relativistic mean field (RMF) models. The correlations between the nuclear matter incompressibility and the isospin dependent term of the finite nucleus incompressibility is elucidated by using the Thomas-Fermi approximation. The Coulomb term is also studied by u

K. A. P. Singh, Prasad Subramanian

A wide variety of transient events in the solar corona seem to require explanations that invoke fast reconnection. Theoretical models explaining fast reconnection often rely on enhanced resistivity. We start with data derived from observed reconnection rates in solar flares and seek to reconcile them with the chaos-induced resistivity model of Numata & Yoshi

S. Chaturvedi, E. Ercolessi, G. Marmo, G. Morandi

We present a simple derivation of the matrix Riccati equations governing the reduced dynamics as one descends from the group U(N) describing the Schroedinger evolution of an N-level quantum system to the various coset spaces, Grassmanian manifolds, associated with it. The special case pertaining to the geometric phase in N-level systems is described in detai

Leif Svalgaard, Edward W. Cliver

We describe the derivation of the InterHourly Variability (IHV) index of geomagnetic activity. The IHV-index for a geomagnetic element is mechanically derived from hourly values as the sum of the unsigned differences between adjacent hours over a seven-hour interval centered on local midnight. The index is derived separately for stations in both hemispheres

K. Kobayashi, M. Mine, M. Okumura, Y. Yamanaka

We study the dynamics of Bose-Einstein condensates flowing in optical lattices on the basis of quantum field theory. For such a system, a Bose-Einstein condensate shows a unstable behavior which is called the dynamical instability. The unstable system is characterized by the appearance of modes with complex eigenvalues. Expanding the field operator in terms

Dylan Bowden, James Howie

Given an abelian group $A$ and a Lie group $G$, we construct a bilinear pairing from $A\timesπ_1({\mathcal R})$ to $π_1(G)$, where $\mathcal R$ is a subvariety of the variety of representations $A\to G$. In the case where $A$ is the peripheral subgroup of a torus or two-bridge knot group, $G=S^1$ and $\mathcal R$ is a certain variety of representations arisi

M. K. Suleymanov, E. U. Khan, K. Ahmed, Mahnaz Q. Haseeb

Some of the centrality experiments indicate regime change and saturation in the behavior of characteristics of the secondary particles. It is observed as a critical phenomenon for hadron-nuclear, nuclear-nuclear interactions and ultrarelativistic heavy ion collisions. The existing simple models do not explain the effect. We believe that the responsible mecha

Anjan S. Joshipura, Bhavik P. Kodrani

The multi-Higgs models having spontaneous CP violation (SPCV) and natural flavor conservation (NFC) lead to a real CKM matrix $V$ contradicting current evidence in favour of a complex $V$. This contradiction can be removed by using a generalized $μ$-$τ$ (called 23) symmetry in place of the discrete symmetry conventionally used to obtain NFC. If 23 symmetry i

Madhubrata Bhattacharya, G. Gangopadhyay

Half life values for proton radioactivity in nuclei have been calculated in the WKB approximation. The microscopic proton-nucleus potential has been obtained by folding the densities of daughter nuclei with two microscopic NN interactions, DDM3Y and JLM. The densities have been obtained in the Relativistic Mean Field approach in the spherical approximation u

Narendra Sahu

We present a TeV scale model for leptogenesis where the origin of neutrino masses are independent of the scale of leptogenesis. As a result, the model could be extended to explain {\it dark matter, neutrino masses and leptogenesis at the TeV scale}. The most attractive feature of this model is that it predicts a few hundred GeV triplet Higgs scalar that can

Jun-ichi Nakashima, Shuji Deguchi

We present the results of SiO millimeter-line observations of a sample of known SiO maser sources covering a wide dust-temperature range. A cold part of the sample was selected from the SiO maser sources found in our recent SiO maser survey of cold dusty objects. The aim of the present research is to investigate the causes of the correlation between infrared

Makoto Umeki

The motion of assemblies of point vortices in a periodic parallelogram can be described by the complex position $z_j(t)$ whose time derivative is given by the sum of the complex velocities induced by other vortices and the solid rotation centered at $z_j$. A numerical simulation up to 100 vortices in a square periodic box is performed with various initial co

Angel V Kumchev

Let $k \ge 2$ and $α_1, β_1, ..., α_k, β_k$ be reals such that the $α_i$'s are irrational and greater than 1. Suppose further that some ratio $α_i/α_j$ is irrational. We study the representations of an integer $n$ in the form $$ p_1 + p_2 + ... + p_k = n, $$ where $p_i$ is a prime from the Beatty sequence $$ \mathcal B_i = \left\{n \in \mathbb N : n = [

B. Ananthanarayan, Sunanda Banerjee, K. Shivaraj, A. Upadhyay

We attempt a comprehensive analysis of the low lying charm meson states which present several puzzles, including the poor determination of masses of several non-strange excited mesons. We use the well-determined masses of the ground states and the strange first excited states to `predict' the mass of the non-strange first excited state in the framework o

Y. Wakabayashi, M. H. Upton, S. Grenier, J. P. Hill

We report the first observation of `orbital truncation rods' -- the scattering arising from the termination of bulk orbital order at the surface of a crystal. The x-ray measurements, performed on a cleaved, single-layered perovskite, La0.5Sr1.5MnO4, reveal that while the crystallographic surface is atomically smooth, the orbital `surface' is much rou

R. Mecheri, E. Marsch

Remote observations of coronal holes have strongly implicated the kinetic interactions of ion-cyclotron waves with ions as a principal mechanism for plasma heating and acceleration of the fast solar wind. In order to study these waves, a linear perturbation analysis is used in the work frame of the collisionless multi-fluid model. We consider a non-uniform b

Xiao-Zhong Yuan, Hsi-Sheng Goan, Ka-Di Zhu

Using the spin wave approximation, we study the decoherence dynamics of a central spin coupled to an antiferromagnetic environment under the application of an external global magnetic field. The external magnetic field affects the decoherence process through its effect on the antiferromagnetic environment. It is shown explicitly that the decoherence factor w

Guoqing Wu, W. G. Clark, S. E. Brown, J. S. Brooks

$^{77}$Se-NMR spectrum and frequency shift measurements in the paramagnetic metal (PM) and antiferromagnetic insulating (AFI) phases are reported for a small single crystal of the organic conductor $λ-$(BETS)$_{2}$FeCl$_{4}$ as a function of temperature ($T$) and field alignment for an applied magnetic field $B_{0}$ = 9 T. The results show that in the low $T

E. Javier Elizondo, Shun-Ichi Kimura

The Euler characteristic of all the Chow varieties, of a fixed projective variety, can be collected in a formal power series called the Euler-Chow series. This series coincides with the Hilbert series when the Picard group is a finite generated free abelian group. It is an interesting open problem to find for which varieties this series is rational. A few ca

Zoltan Ligeti

Recent developments for mixing and CP violation in the D0 and Bs systems are reviewed, including (i) the recently emerging evidence for D0-D0bar mixing and the interpretations of the measurements; (ii) the theoretical status of the calculations of Delta(Gamma_D) and Delta(m_D); (iii) some implications of the measurement of Bs mixing for new physics.

K. Paech, W. Bauer, S. Pratt

We investigate the average sizes of the $n$ largest fragments in nuclear multifragmentation events near the critical point of the nuclear matter phase diagram. We perform analytic calculations employing Poisson statistics as well as Monte Carlo simulations of the percolation type. We find that previous claims of manifestations of Zipf's Law in the rank-o

Moira I. Gresham, Mark B. Wise

New physics at the weak scale that can couple to quarks typically gives rise to unacceptably large flavor changing neutral currents. An attractive way to avoid this problem is to impose the principal of minimal flavor violation (MFV). Recently it was noted that in MFV only scalars with the same gauge quantum numbers as the standard model Higgs doublet or col

Sascha Husa, Mark Hannam, Jose A. Gonzalez, Ulrich Sperhake

Standard choices of quasi-circular orbit parameters for black-hole binary evolutions result in eccentric inspiral. We introduce a conceptually simple method, which is to integrate the post-Newtonian equations of motion through hundreds of orbits, and read off the values of the momenta at the separation at which we wish to start a fully general relativistic n

Lester O. Hedges, Juan P. Garrahan

Transitions between metabasins in supercooled liquids seem to occur through rapid "democratic" collective particle rearrangements. Here we show that this apparent homogeneous particle motion is a direct consequence of dynamic facilitation. We do so by studying metabasin transitions in facilitated spin models and constrained lattice gases. We find tha

Brice Ménard, Daniel Nestor, David Turnshek, Anna Quider

Using a sample of almost 7000 strong MgII absorbers with 0.4 < z < 2.2 detected in the SDSS DR4 dataset, we investigate the gravitational lensing and dust extinction effects they induce on background quasars. After carefully quantifying several selection biases, we isolate the reddening effects as a function of redshift and absorber rest equivalent width, W_

Paulo Tabuada

The objective of this paper is to solve the controller synthesis problem for bisimulation equivalence in a wide variety of scenarios including discrete-event systems, nonlinear control systems, behavioral systems, hybrid systems and many others. This will be accomplished by showing that the arguments underlying proofs of existence and methods for the constru

R. Enberg, P. J. Fox, L. J. Hall, A. Y. Papaioannou

The Standard Model Higgs suffers from the hierarchy problem, typically implying new states within the reach of the LHC. If the Higgs is very heavy (~500 GeV) the states that cutoff the quadratic divergence may be beyond the reach of the LHC. However, in this case precision electroweak data require the Standard Model to be augmented with new states at the ele

Utpal Roy, Suranjana Ghosh, Kaushik Bhattacharya

In quantum mechanics textbooks the momentum operator is defined in the Cartesian coordinates and rarely the form of the momentum operator in spherical polar coordinates is discussed. Consequently one always generalizes the Cartesian prescription to other coordinates and falls in a trap. In this work we introduce the difficulties one faces when the question o

Milton Ruiz, Miguel Alcubierre, Dario Nunez

Several interesting astrophysical phenomena are symmetric with respect to the rotation axis, like the head-on collision of compact bodies, the collapse and/or accretion of fields with a large variety of geometries, or some forms of gravitational waves. Most current numerical relativity codes, however, can not take advantage of these symmetries due to the fac

Brian Rider, Xin Zhou

For a broad class of unitary ensembles of random matrices we demonstrate the universal nature of the Janossy densities of eigenvalues near the spectral edge, providing a different formulation of the probability distributions of the limiting second, third, etc. largest eigenvalues of the ensembles in question. The approach is based on a representation of the

Stanisław Prus, Andrzej Wiśnicki

It is shown that if a Banach space X has the weak Banach-Saks property and the weak fixed point property for nonexpansive mappings and Y satisfies property asymptotic (P) (which is weaker than the condition WCS(Y)>1), then the direct sum of X and Y endowed with a strictly monotone norm enjoys the weak fixed point property. The same conclusion is valid if X a

Chris J. Willott, Philippe Delorme, Alain Omont, Jacqueline Bergeron

The Canada-France High-z Quasar Survey (CFHQS) is an optical survey designed to locate quasars during the epoch of reionization. In this paper we present the discovery of the first four CFHQS quasars at redshift greater than 6, including the most distant known quasar, CFHQS J2329-0301 at z=6.43. We describe the observational method used to identify the quasa

Jeremy S. Heyl

Recent observations of white dwarfs in globular clusters indicate that these stars may get a velocity kick during their time as giants. This velocity kick could originate naturally if the mass loss while on the asymptotic giant branch is slightly asymmetric. If white dwarfs get a kick comparable to the orbital velocity of the binary, the initial Runge-Lenz v

Artur O. Lopes, Elismar R. Oliveira

Associated to a IFS one can consider a continuous map $\hatσ : [0,1]\times Σ\to [0,1]\times Σ$, defined by $\hatσ(x,w)=(τ_{X_{1}(w)}(x), σ(w))$ were $Σ=\{0,1, ..., d-1\}^{\mathbb{N}}$, $σ: Σ\to Σ$ is given by$σ(w_{1},w_{2},w_{3},...)=(w_{2},w_{3},w_{4}...)$ and $X_{k} : Σ\to \{0,1, ..., n-1\}$ is the projection on the coordinate $k$. A $ρ$-weighted system, $

C. Robinson Tompkins

We define a morphism based upon a Latin square that generalizes the Thue-Morse morphism. We prove that fixed points of this morphism are overlap-free sequences generalizing results of Allouche - Shallit and Frid.

A. C. Clark, J. T. West, M. H. W. Chan

It has been proposed that the observed nonclassical rotational inertia (NCRI) in solid helium results from the superflow of thin liquid films along interconnected grain boundaries within the sample. We have carried out new torsional oscillator measurements on large helium crystals grown under constant temperature and pressure. We observe NCRI in all samples,

A. K. H. Kong, Y. J. Yang, P. -Y. Hsieh, D. S. Y. Mak

We report the identification of a recurrent ultraluminous X-ray source (ULX), a highly absorbed X-ray source (possibly a background AGN), and a young supernova remnant near the center of the starburst galaxy M82. From a series of Chandra observations taken from 1999 to 2005, we found that the transient ULX first appeared in 1999 October. The source turned of

M. Miranda, A. V. Macciò

Warm Dark Matter (WDM) has been invoked to resolve apparent conflicts of Cold Dark Matter (CDM) models with observations on subgalactic scales. In this work we provide a new and independent lower limit for the WDM particle mass (e.g. sterile neutrino) through the analysis of image fluxes in gravitationally lensed QSOs. Starting from a theoretical unperturbed

Jeremy S. Heyl

The wind of an asymptotic-giant-branch stars is sufficiently strong that if it is slightly asymmetric, it can propel the star outside of the open cluster of its birth or significantly alter its trajectory through a globular cluster; therefore, if these stellar winds are asymmetric, one would expect a deficit of white dwarfs of all ages in open clusters and f

De-en Jiang, Bobby G. Sumpter, Sheng Dai

Magnetism in nanographenes (also know as polycyclic aromatic hydrocarbons, or PAHs) are studied with first principles density functional calculations. We find that an antiferromagnetic (AFM) phase appears as the PAH reaches a certain size. This AFM phase in PAHs has the same origin as the one in infinitely long zigzag-edged graphene nanoribbons, namely, from

Beniamino Cappelletti Montano

We find necessary and sufficient conditions for the bi-Legendrian connection $\nabla$ associated to a bi-Legendrian structure $(\cal F,\cal G)$ on a contact metric manifold $(M,ϕ,ξ,η,g)$ being a metric connection and then we give conditions ensuring that $\nabla$ coincides with the (generalized) Tanaka-Webster connection of $(M,ϕ,ξ,η,g)$. Using these results

Alexei G. Kritsuk, Paolo Padoan, Rick Wagner, Michael L. Norman

We use large-scale three-dimensional simulations of supersonic Euler turbulence to study the physics of a highly compressible cascade. Our numerical experiments describe non-magnetized driven turbulent flows with an isothermal equation of state and an rms Mach number of 6. We find that the inertial range velocity scaling deviates strongly from the incompress

Sanefumi Moriyama, Alessandro Torrielli

We express the classical r-matrix of AdS/CFT in terms of tensor products involving an infinite family of generators, which takes a form suggestive of the universal expression obtained from a Yangian double. This should provide an insight into the structure of the infinite dimensional symmetry algebra underlying the integrability of the model, and give a clue

Mordehai Milgrom

I consider in light of MOND the three debris galaxies discussed recently by Bournaud et al.. These exhibit mass discrepancies of a factor of a few within several scale lengths of the visible galaxy, which, arguably, flies in the face of the cold dark matter paradigm. I show here that the rotational velocities predicted by MOND agree well with the observed ve

Adrian Röllin

The application of Stein&#39;s method for distributional approximation often involves so called Stein factors (also called &#39;magic factors&#39;) in the bound of the solutions to Stein equations. However, in some cases these factors contain additional (undesirable) logarithmic terms. It has been shown for many Stein factors that the known bounds are sharp

Marcos Jardim, Rafael F. Leao

We use Dirac operator techniques to a establish sharp lower bound for the first eigenvalue of the Dolbeault Laplacian twisted by Hermitian-Einstein connections on vector bundles of negative degree over compact Kähler manifolds.

A. W. Beckwith

In 2001, Seth Lloyd presented a radical new critique of the universe as a quantum computing device, with an upper limit of bit calculations of the order of 10 to the 120 power. We find that his calculations permit us to reconcile the existance of a huge cosmological constant 10 to the minus 43 seconds after the big bang, with a resulting huge relic graviton

I. Dana, V. Ramareddy, I. Talukdar, G. S. Summy

Quantum-resonance ratchets associated with the periodically kicked particle are experimentally realized for the first time. This is achieved by using a Bose-Einstein condensate exposed to a pulsed standing light wave and prepared in an initial state differing from the usual plane wave. Both the standing-wave potential and the initial state have a point symme

Matteo Rizzi, Simone Montangero, Guifre&#39; Vidal

We describe an algorithm to simulate time evolution using the Multi-scale Entanglement Renormalization Ansatz (MERA) and test it by studying a critical Ising chain with periodic boundary conditions and with up to L ~ 10^6 quantum spins. The cost of a simulation, which scales as L log(L), is reduced to log(L) when the system is invariant under translations. B

John D. Monnier, M. Zhao, E. Pedretti, N. Thureau

Spatially resolving the surfaces of nearby stars promises to advance our knowledge of stellar physics. Using optical long-baseline interferometry, we present here a near-infrared image of the rapidly rotating hot star Altair with <1 milliarcsecond resolution. The image clearly reveals the strong effect of gravity darkening on the highly-distorted stellar pho

Stefan Hilbert, R. Benton Metcalf, S. D. M. White

21-cm emission from neutral hydrogen during and before the epoch of cosmic reionisation is gravitationally lensed by material at all lower redshifts. Low-frequency radio observations of this emission can be used to reconstruct the projected mass distribution of foreground material, both light and dark. We compare the potential imaging capabilities of such 21

Biqin Huang, Douwe J. Monsma, Ian Appelbaum

We use all-electrical methods to inject, transport, and detect spin-polarized electrons vertically through a 350-micron-thick undoped single-crystal silicon wafer. Spin precession measurements in a perpendicular magnetic field at different accelerating electric fields reveal high spin coherence with at least 13pi precession angles. The magnetic-field spacing

A. Sitek, P. Machnikowski

We study theoretically the nonlinear four wave mixing (FWM) response of an ensemble of coupled pairs of quantum dots (quantum dot molecules). We discuss the shape of the FWM echo signal depending on the parameters of the ensemble: the statistics of transition energies and the degree of size correlations between the dots forming the molecules.

R. Millo, P. Faccioli

We study the response of the QCD vacuum to an external magnetic field, in the presence of strong CP violation. Using chiral perturbation theory and large N_c expansion, we show that the external field would polarize quantum fluctuations and induce an electric dipole moment of the vacuum, along the direction of the magnetic field. We estimate the magnitude of

M. Boggi, P. Lochak

Let ${\cal M}_{g,[n]}$, for $2g-2+n>0$, be the D-M moduli stack of smooth curves of genus $g$ labeled by $n$ unordered distinct points. The main result of the paper is that a finite, connected étale cover ${\cal M}^ł$ of ${\cal M}_{g,[n]}$, defined over a sub-$p$-adic field $k$, is &#34;almost&#34; anabelian in the sense conjectured by Grothendieck for curve

Chuan-Hung Chen, Chao-Qiang Geng

Unparticles proposed by Georgi carry CP conserving phases in their propagators. We demonstrate that these peculiar phases have an important impact on CP violation. Without including the strong QCD phases, we study the unparticle phase effects on the direct CP asymmetries in the exclusive decays of $\bar B_d\to π^{+} π^{-}$ and $B\to πK$, in which the flavor

Nikolai Nikolov, Pascal J. Thomas

Given $A\inΩ_n,$ the $n^2$-dimensional spectral unit ball, we show that $B$ is a &#34;generalized&#34; tangent vector at $A$ to an entire curve in $Ω_n$ if and only if $B$ is in the tangent cone $C_A$ to the isospectral variety at $A.$ In the case of $Ω_3,$ the zero set of this metric is completely described.

Debraj Chakrabarti, Rasul Shafikov

It is proved that CR functions on a quadratic cone M in $\C^n$, n>1, admit one-sided holomorphic extension if and only if M does not have two-sided support, a geometric condition on M which generalizes minimality in the sense of Tumanov. A biholomorphic classification of quadratic cones in $\C^2$ is also given.

Krzysztof Byczuk, Dieter Vollhardt

We formulate a bosonic dynamical mean-field theory (B-DMFT) which provides a comprehensive, thermodynamically consistent framework for the theoretical investigation of correlated lattice bosons. The B-DMFT is applicable for arbitrary values of the coupling parameters and temperature and becomes exact in the limit of high spatial dimensions d or coordination

Ben Craps, Oleg Evnin

Attempts to consider evolution across space-time singularities often lead to quantum systems with time-dependent Hamiltonians developing an isolated singularity as a function of time. Examples include matrix theory in certain singular time-dependent backgounds and free quantum fields on the two-dimensional compactified Milne universe. Due to the presence of

Partha Chowdhury, P. C. Ray, Saibal Ray

In this paper we have investigated the occurrence rate of high energetic(E>10 MeV) solar electron flares measured by IMP-8 spacecraft of NASA for solar cycle 21 (June, 1976 to August, 1986) first time by three different methods to detect periodicities accurately. Power-spectrum analysis confirms a periodicity ~155 days which is in consistent with the result

G. De Cesare, A. Bazzano, S. Martinez Nunez, G. Stratta

KS 1741-293, discovered in 1989 by the X-ray camera TTM in the Kvant module of the Mir space station and identified as an X-ray burster, has not been detected in the hard X band until the advent of the INTEGRAL observatory. Moreover this source has been recently object of scientific discussion, being also associated to a nearby extended radio source that in

Ludovic Pricoupenko

Low energy scattering amplitudes for two atoms in one- and two-dimensional atomic wave guides are derived for short range isotropic and resonant interactions in high partial wave channels. Taking into account the finite width of the resonance which was neglected in previous works is shown to have important implications in the properties of the confinement in

Fumio Hiroshima, Jozsef Lorinczi

A Feynman-Kac-type formula for a Lévy and an infinite dimensional Gaussian random process associated with a quantized radiation field is derived. In particular, a functional integral representation of $e^{-t\PF}$ generated by the Pauli-Fierz Hamiltonian with spin $\han$ in non-relativistic quantum electrodynamics is constructed. When no external potential is

Steven A. Balbus, Pierre Henri

We investigate the behavior of the magnetic Prandtl number (ratio of microscopic viscosity to resistivity) for accretion sources. Generally this number is very small in standard accretion disk models, but can become larger than unity within $\sim 50$ Schwarzschild radii of the central mass. Recent numerical investigations suggest a marked dependence of the l

D. C. Cabra, N. E. Grandi

Starting from a microscopic description of a system of strongly interacting electrons in a strong magnetic field in a finite geometry, we construct the boundary low energy effective theory for a fractional quantum Hall droplet taking into account the effects of a smooth edge. The effective theory obtained is the standard chiral boson theory (chiral Luttinger

Birger Horstmann, Juan Ignacio Cirac, Tommaso Roscilde

We investigate the behavior of ultracold bosons in optical lattices with a disorder potential generated via a secondary species frozen in random configurations. The statistics of disorder is associated with the physical state in which the secondary species is prepared. The resulting random potential, albeit displaying algebraic correlations, is found to lead

Cecilia Albertsson, Ladislav Hlavaty, Libor Snobl

Conditions for the gluing matrix defining consistent boundary conditions of two-dimensional nonlinear sigma-models are analyzed and reformulated. Transformation properties of the right-invariant fields under Poisson-Lie T-plurality are used to derive a formula for the transformation of the boundary conditions. Examples of transformation of D-branes in two an

Pascal Moyal

In this paper we present a stability criterion for finite measure-valued stochastic recursions, generalizing Loynes&#39;s Theorem to spaces of measures. This result provides conditions for the reach of a &#34;total stationary state&#34; for the queue with an infinity of servers and the single-server SRPT queue. Indeed, we give in both cases a condition of ex

Ulf R. Pedersen, Nicholas P. Bailey, Jeppe C. Dyre, Thomas B. Schrøder

We report observation of crystallization of the glass-forming binary Lennard-Jones liquid first used by Wahnström [G. Wahnström, Phys. Rev. A 44, 3752 (1991)]. Molecular dynamics simulations of the metastable liquid on a timescale of microseconds were performed. The liquid crystallized spontaneously. The crystal structure was identified as MgZn_2. Formation

D. Burgarella, E. Le Floc&#39;h, T. T. Takeuchi, J. S. Huang

Ultraviolet (UV) galaxies have been selected from GALEX. The presence of a FUV-dropout in their spectral energy distributions proved to be a very complete (83.3%) but not very efficient (21.4%) tool for identifying Lyman Break Galaxies (LBGs) at z~1. We divide the LBG sample into two sub-classes: red LBGs (RLBGs) detected at 24 micron which are mainly Lumino

Ronald Ortner

In arrangements of pseudocircles (Jordan curves) the weight of a vertex (intersection point) is the number of pseudocircles that contain the vertex in its interior. We give improved upper bounds on the number of vertices of weight <=k in certain arrangements of pseudocircles in the plane. In particular, forbidding certain subarrangements we improve the known

C. Y. Yang, P. Halder, O. Appel, D. Hansen

We demonstrate an efficient scheme for continuous trap loading based upon spatially selective optical pumping. We discuss the case of $^{1}$S$_{0}$ calcium atoms in an optical dipole trap (ODT), however, similar strategies should be applicable to a wide range of atomic species. Our starting point is a reservoir of moderately cold ($\approx 300 μ$K) metastabl

Yusuke Sasano

We present {\it symmetric Hamiltonians} for the degenerate Garnier systems in two variables. For these symmetric Hamiltonians, we make the symmetry and holomorphy conditions, and we also make a generalization of these systems involving symmetry and holomorphy conditions inductively. We also show the confluence process among each system by taking the coupling

F. Aharonian

The high-frequency peaked BL Lac PKS 2155-304 at redshift z=0.116 is a well-known VHE (>100 GeV) gamma-ray emitter. Since 2002 its VHE flux has been monitored using the H.E.S.S. stereoscopic array of imaging atmospheric-Cherenkov telescopes in Namibia. During the July 2006 dark period, the average VHE flux was measured to be more than ten times typical value

Srikanth K. Iyer, D. Manjunath, D. Yogeshwaran

Let P := {X_i,i >= 1} be a stationary Poisson point process in R^d, {C_i,i >= 1} be a sequence of i.i.d. random sets in R^d, and {Y_i^t; t \geq 0, i >= 1} be i.i.d. {0,1}-valued continuous time stationary Markov chains. We define the Markov-Poisson-Boolean model C_t := {Y_i^t(X_i + C_i), i >= 1}. C_t represents the coverage process at time t. We first obtain

Daisy S. Y. Mak, Chun. S. J. Pun, Albert K. H. Kong

We presented the result of a high resolution (FWHM~0.5&#39;&#39;) 12 ks Chandra HRC-I observation of the starburst galaxy IC342 taken on 2 April 2006. We identified 23 X-ray sources within the central 30&#39; x 30&#39; region of IC342. Our HRC-I observation resolved the historical Ultraluminous X-ray sources (ULX), X3, near the nucleus into 2 sources, namely

Eric Cances, Amelie Deleurence, Mathieu Lewin

We present a new variational model for computing the electronic first-order density matrix of a crystalline material in presence of a local defect. A natural way to obtain variational discretizations of this model is to expand the difference Q between the density matrix of the defective crystal and the density matrix of the perfect crystal, in a basis of pre

Ian Hambleton, Ozgun Unlu

Let $p$ be an odd prime. We construct a non-abelian extension $Γ$ of $S^1$ by $Z/p \times Z/p$, and prove that any finite subgroup of $Γ$ acts freely and smoothly on $S^{2p-1} \times S^{2p-1}$. In particular, for each odd prime $p$ we obtain free smooth actions of infinitely many non-metacyclic rank two $p$-groups on $S^{2p-1} \times S^{2p-1}$. These results

Stéphanie Allassonnière, Estelle Kuhn, Alain Trouvé

The problem of the definition and the estimation of generative models based on deformable templates from raw data is of particular importance for modelling non aligned data affected by various types of geometrical variability. This is especially true in shape modelling in the computer vision community or in probabilistic atlas building for Computational Anat

R. Schofbeck, H. Eberl

We have calculated the two-loop strong interaction corrections to the chargino pole masses in the DRbar&#39;-scheme in the Minimal Supersymmetric Standard Model (MSSM) with complex parameters. We have performed a detailed numerical analysis for a particular point in the parameter space and found corrections of a few tenths of a percent. We provide a computer

Yu Nakayama

We further investigate the dimensional duality (D-duality) proposed in arXiv:0705.0550 by mainly focusing on the properties of D-branes in this background. We derive the world-sheet correspondence of static D-branes, and discuss the fate of non-static D-branes from the world-sheet viewpoint. The quantum string production with or without D-branes is also stud

Gang Mu, Yue Wang, Lei Shan, Hai-Hu Wen

We measured the resistivity, diamagnetization and low temperature specific heat of the newly discovered noncentrosymmetric superconductor $Mg_{10}Ir_{19}B_{16}$. It is found that the superconducting gap has an s-wave symmetry with a value of about $Δ_0 \approx$ 0.6 meV, and the ratio $Δ_0/k_BT_c\approx1.86$ indicates a weak coupling for the superconductivity

T. Adachi, K. Kanada, T. Saito, A. Oosawa

Spin-lattice relaxation rate $T_1^{-1}$ of $^1$H-NMR has been measured in (CH$_3$)$_2$CHNH$_3$Cu(Cl$_x$Br$_{1-x}$)$_3$ with $x=0.88$, which has been reported to be gapped system with singlet ground state from the previous macroscopic magnetization and specific heat measurements, in order to investigate the bond randomness effect microscopically in the gapped

C. Bulutay

Embedded Si and Ge nanocrystals (NCs) in wide band-gap matrices are studied theoretically using an atomistic pseudopotential approach. From small clusters to large NCs containing on the order of several thousand atoms are considered. Effective band-gap values as a function of NC diameter reproduce very well the available experimental and theoretical data. It

Mohammad Hafezi, Anders S. Sorensen, Mikhail D. Lukin, Eugene Demler

We study Chern numbers to characterize the ground state of strongly interacting systems on a lattice. This method allows us to perform a numerical characterization of bosonic fractional quantum Hall (FQH) states on a lattice where conventional overlap calculation with known continuum case such as Laughlin state, breaks down due to the lattice structure or di

Hong Yao, Wei-Feng Tsai, Steven A. Kivelson

The zero temperature phase diagram of the checkerboard Hubbard model is obtained in the solvable limit in which it consists of weakly coupled square plaquettes. As a function of the on-site Coulomb repulsion U and the density of holes per site, x, we demonstrate the existence of at least 16 distinct phases. For instance, at zero doping, the ground state is a

Emma Y. Jin, Jing Qin, Christian M. Reidys

In this paper we present a novel framework for sequence to shape maps. These combinatorial maps realize exponentially many shapes, and have preimages which contain extended connected subgraphs of diameter n (neutral networks). We prove that all basic properties of RNA folding maps also hold for combinatorial maps. Our construction is as follows: suppose we a

Britton D. Smith, Steinn Sigurdsson, Tom Abel

The addition of metals to any gas can significantly alter its evolution by increasing the rate of radiative cooling. In star-forming environments, enhanced cooling can potentially lead to fragmentation and the formation of low-mass stars, where metal-free gas-clouds have been shown not to fragment. Adding metal cooling to numerical simulations has traditiona

Stephen R. Williams, Denis J. Evans

We examine the question of whether the formal expressions of equilibrium statistical mechanics can be applied to time independent non-dissipative systems that are not in true thermodynamic equilibrium and are nonergodic. By assuming the phase space may be divided into time independent, locally ergodic domains, we argue that within such domains the relative p

Ivan Cheltsov, Jihun Park, Joonyeong Won

We study log canonical thresholds on quartic threefolds, quintic fourfolds, and double spaces. As an application, we show that they have a Kaehler-Einstein metric if they are general.