May 2009 arXiv papers — page 4

Federico Becca, Luca Capriotti, Alberto Parola, Sandro Sorella

Variational wave functions containing electronic pairing and suppressed charge fluctuations (i.e., projected BCS states) have been proposed as the paradigm for disordered magnetic systems (including spin liquids). Here we discuss the general properties of these states in one and two dimensions, and show that different quantum phases may be described with hig

Gabriel Niebler, Gianaurelio Cuniberti, Tomas Novotny

We present an analytical derivation of the excess current in Josephson junctions within the Octavio-Tinkham-Blonder-Klapwijk theory for both symmetric and asymmetric barrier strengths. We confirm the result found numerically by Flensberg et al. for equal barriers [Phys. Rev. B 38, 8707 (1988)], including the prediction of negative excess current for low tran

Joaquin Garcia-Alfaro, Guillermo Navarro-Arribas

Web applications are becoming truly pervasive in all kinds of business models and organizations. Today, most critical systems such as those related to health care, banking, or even emergency response, are relying on these applications. They must therefore include, in addition to the expected value offered to their users, reliable mechanisms to ensure their s

N. Paar, Y. F. Niu, D. Vretenar, J. Meng

The electric dipole response of $^{140}$Ce is investigated using the fully consistent relativistic quasiparticle random phase approximation. By analyzing the isospin structure of the E1 response, it is shown that the low-energy (pygmy) strength separates into two segments with different isospin character. The more pronounced pygmy structure at lower energy i

The FOCUS Collaboration

Using data from FOCUS (E831) experiment at Fermilab, we present a model independent partial-wave analysis of the $K^-π^+$ S-wave amplitude from the decay $D^+ \to K^-π^+π^+$. The S-wave is a generic complex function to be determined directly from the data fit. The P- and D-waves are parameterized by a sum of Breit-Wigner amplitudes. The measurement of the S-

Stefano Bianchi, Giorgio Matt, Francesco Tamborra, Marco Chiaberge

The soft X-ray emission in obscured active galactic nuclei (AGN) is dominated by emission lines, produced in a gas photoionized by the nuclear continuum and likely spatially coincident with the optical narrow line region (NLR). However, a fraction of the observed soft X-ray flux appears like a featureless power law continuum. If the continuum underlying the

J. V. Dawson

The Double Chooz experiment is the first of the next wave of reactor experiments searching for a non-vanishing value of the mixing angle theta_13. The experimental concept and detector design are presented, and the most pertinent backgrounds are discussed. Operation of the far detector is expected to begin by the end of 2009. Installation of the near detecto

W. Ishibashi, T. J. -L. Courvoisier

X-ray variability in Active Galactic Nuclei (AGN) is commonly analysed in terms of the Power Spectral Density (PSD). The break observed in the power spectrum can be interpreted as a characteristic X-ray variability time scale. Here we study variability properties within the framework of clumpy accretion flows, in which shocks between accreting elements accou

Yoonbai Kim, O-Kab Kwon, Hiroaki Nakajima, D. D. Tolla

In the context of low-energy effective theory of multiple M2-branes, we construct the interaction terms between the world-volume fields of M2-branes and the antisymmetric tensor fields of three- and six-forms. By utilizing the compactification procedure, we show coincidence between the dimensionally reduced coupling and the R-R coupling to D-branes in type I

L. Fernández Jambrina

In this talk we shall show a perfect fluid cosmological model and its properties. The model possesses an orthogonally transitive abelian two-dimensional group of isometries that corresponds to cylindrical symmetry. The matter content is a stiff fluid that satisfies the energy and generic conditions. The metric is not separable in comoving coordinates for the

Vittorio Colao, Laurentiu Leustean, Genaro Lopez, Victoria Martin-Marquez

Alternative iterative methods for a nonexpansive mapping in a Banach space are proposed and proved to be convergent to a common solution to a fixed point problem and a variational inequality. We give rates of asymptotic regularity for such iterations using proof-theoretic techniques. Some applications of the convergence results are presented.

L. Fernández-Jambrina

In this talk we show a stiff fluid solution of the Einstein equations for a cylindrically symmetric spacetime. The main features of this metric are that it is non-separable in comoving coordinates for the congruence of the worldlineS of the fluid and that it yields regular curvature invariants.

Francis N. C. Paraan, Alessandro Silva

We study the statistics of the work done in a zero temperature quench of the coupling constant in the Dicke model describing the interaction between a gas of two level atoms and a single electromagnetic cavity mode. When either the final or the initial coupling constants approach the critical coupling $λ_c$ that separates the normal and superradiant phases o

Olivier Rabaste, Eric Chassande-Mottin, Archana Pai

The gravitational wave detectors currently in operation perform the analysis of their scientific data jointly. Concerning the search for bursting sources, coherent data analysis methods have been shown to be more efficient. In the coherent approach, the data collected by the detectors are time-shifted and linearly combined so that the signatures received by

A. Moosavi, M. Rauscher, S. Dietrich

Mesoscopic hydrodynamic equations are solved to investigate the dynamics of nanodroplets positioned near a topographic step of the supporting substrate. Our results show that the dynamics depends on the characteristic length scales of the system given by the height of the step and the size of the nanodroplets as well as on the constituting substances of both

Martin Ostermeyer, Dietmar Korn, Dirk Puhlmann

Space momentum entangled photon pairs are generated from type II parametric down conversion in a beta barium borate crystal. The correlations in the positions of photons in the near field and far field planes with regard to the generating crystal are observed in both transverse dimensions using scanning fiber probes. The space-momentum correlation is charact

C. M. Zhang, D. T. Wickramasinghe, L. Ferrario

The evolution of the magnetic field of an accreting magnetic white dwarf with an initially dipolar field at the surface has been studied for non-spherical accretion under simplifying assumptions. Accretion on to the polar regions tends to advect the field toward the stellar equator which is then buried. This tendency is countered by Ohmic diffusion and magne

J Kocinski, M Wierzbicki

The corepresentation theory of continuous groups is presented without the assumption that the subgroup $G$ of the group with antilinear operations is unitary. The formulas of the corepresentation theory with unitary groups $G$ can be obtained from this presentation.

T. K. Jha

The role of light scalar meson `$f_0 (600)$' is investigated in nuclear matter in an Effective chiral model in the mean-field approach. For the purpose, we scan the properties of the matter at various saturation densities imposing constraint such as the vacuum value of the pion decay constant $f_π \approx 131 ~MeV$. With a simple approach, the bound on t

X. Fabreges, S. Petit, I. Mirebeau, S. Pailhes

We have performed high resolution neutron diffraction and inelastic neutron scattering experiments in the frustrated multiferroic hexagonal compounds RMnO3 (R=Ho, Yb, Sc, Y), which provide evidence of a strong magneto-elastic coupling in the the whole family. We can correlate the atomic positions, the type of magnetic structure and the nature of the spin wav

Fu-Sin Ling

Scalar fields with $SU(2)_L$ quantum numbers provide several viable Dark Matter candidates around the TeV scale. Thanks to scalar quartic interactions, the observed relic density can be obtained for a large range of masses, which we determine. In turn, the constraints on the scalar couplings lead to testable predictions in future direct and indirect searches

D. Huja, A. Meszaros, J. Ripa

The durations of 388 gamma-ray bursts, detected by the Swift satellite, are studied statistically in order to search for their subgroups. Then the results are compared with the results obtained earlier from the BATSE database. The standard chi^2 test is used. Similarly to the BATSE database, the short and long subgroups are well detected also in the Swift da

A. Oneto, E. Zatini

Let $R$ be a one-dimensional, local, Noetherian domain, $\R$ the integral closure of $R$ in its quotient field and $v(R)$ the value set defined by the usual valuation. The aim of the paper is to study the non-negative invariant $b:=(c-δ)r- δ$, where $c, δ, r$ denote the conductor, the length of $\R/R$ and the Cohen Macaulay type, respectively. In particular,

Y. Yan

Kaonic hydrogen is studied with various realistic potentials in an accurate numerical approach based on Sturmian functions. The kaon-proton scattering length extracted from the 1s energy shift of the kaonic hydrogen by applying the Deser-Trueman formula is severely inconsistent with the one derived by directly solving the scattering Schoedinger equation. We

K. Schwarz, A. Karrenbauer, G. Schehr, H. Rieger

Domain walls, optimal droplets and disorder chaos at zero temperature are studied numerically for the solid-on-solid model on a random substrate. It is shown that the ensemble of random curves represented by the domain walls obeys Schramm's left passage formula with kappa=4 whereas their fractal dimension is d_s=1.25, and therefore is NOT described by &#

M. Ebert, W. Paul

Financial markets display scale-free behavior in many different aspects. The power-law behavior of part of the distribution of individual wealth has been recognized by Pareto as early as the nineteenth century. Heavy-tailed and scale-free behavior of the distribution of returns of different financial assets have been confirmed in a series of works. The exist

H. Rostro, B. Cessac, J. C. Vasquez, T. Vieville

We consider the deterministic evolution of a time-discretized spiking network of neurons with connection weights having delays, modeled as a discretized neural network of the generalized integrate and fire (gIF) type. The purpose is to study a class of algorithmic methods allowing to calculate the proper parameters to reproduce exactly a given spike train ge

Guobao Zhang, Mariano Mendez, Diego Altamirano, Tomaso M. Belloni

We have discovered a triple-peaked X-ray burst from the low-mass X-ray binary (LMXB) 4U 1636-53 with the Rossi X-ray Timing Explorer (RXTE). This is the first triple-peaked burst reported from any LMXB using RXTE, and it is only the second burst of this kind observed from any source. (The previous one was also from 4U 1636-53, and was observed with EXOSAT.)

Shuang-Xi Wang, Yu Yang, Bo Sun, Rong-Wu Li

Using first-principles calculations, we systematically study the adsorption behaviors of molecular CO on the Be (0001) surface. By calculating the potential energy surfaces, we find that CO molecularly adsorbs on the Be surface with small energy barriers. The most stable adsorption state is found to be the one at the surface fcc hollow site, and the one at t

T. V. Dudnikova

We consider the lattice dynamics in the half-space. The initial data are random according to a probability measure which enforces slow spatial variation on the linear scale $\varepsilon^{-1}$. We establish two time regimes. For times of order $\varepsilon^{-γ}$, $0<γ<1$, locally the measure converges to a Gaussian measure which is time stationary with a cova

Norihito Toyota

In this article we discuss six degrees of separation, which has been suggested by Milgram&#39;s famous experiment\cite{Milg},\cite{Milg2}, from a theoretical point of view again. Though Milgram&#39;s experiment was partly inspired to Pool and Kochen&#39;s study \cite{Pool} that was made from a theoretical point of view. At the time numerically detailed study

J. S. Kaastra, A. M. Bykov, N. Werner

Thermal X-ray spectra of clusters of galaxies and other sources are commonly calculated assuming Maxwellian electron distributions. There are situations where this approximation is not valid, for instance near interfaces of hot and cold gas and near shocks. The presence of non-thermal electrons affects the X-ray spectrum. To study the role of these electrons

L. M. Voigt, S. L. Bridle

Gravitational lensing shear has the potential to be the most powerful tool for constraining the nature of dark energy. However, accurate measurement of galaxy shear is crucial and has been shown to be non-trivial by the Shear TEsting Programme. Here we demonstrate a fundamental limit to the accuracy achievable by model-fitting techniques, if oversimplistic m

C. Grignon, J. Billard, G. Bosson, O. Bourrion

MiMac is a project of micro-TPC matrix of gaseous (He3, CF4) chambers for direct detection of non-baryonic dark matter. Measurement of both track and ionization energy will allow the electron-recoil discrimination, while access to the directionnality of the tracks will open a unique way to distinguish a geniune WIMP signal from any background. First reconstr

Yshai Avishai, Doron Cohen, Naoto Nagaosa

We show theoretically that a simple one dimensional system (such as metallic wire) can display quantum spin pumping possibly without pushing any charge. It is achieved by applying two slowly varying orthogonal gate electric fields on different sections of the wire, thereby generating local spin-orbit (Rashba) terms such that unitary transformations at differ

C. F. Barenghi, Y. A. Sergeev

Recent experiments on quantum turbulence in superfluid helium made use of small tracer particles to track the motion of quantized vortices, determine velocity statistics and visualize vortex reconnections. A problem with this visualization technique is that it may change the turbulent flow which it visualizes. To address this problem, we derive and solve the

Chushun Tian

This is the second of a series of papers on the special relativistic classical statistical mechanics. Employing the general theory developed in the first paper we rigorously derive the relativistic Vlasov, Landau and Boltzmann equation. The latter two advocate the J{ü}ttner distribution as the equilibrium distribution. We thus, at the full microscopic level,

Neill Lambert, Yueh-nan Chen, Robert Johannsson, Franco Nori

The Dicke model describes N qubits (or two-level atoms) homogenously coupled to a bosonic mode. Here we examine an open-system realization of the Dicke model, which contains critical and chaotic behaviour. In particular, we extend this model to include an additional open transport qubit (TQ) (coupled to the bosonic mode) for passive and active measurements.

Takeshi Fukuyama

We want to correct the misunderstandings on the tetrad (or veilbeins in general) appeared in many text books or review articles. The tetrad should be defined without any condition. $e_{\mu a}=\partial_\mu X_a$ with local Lorentz coordinates $X_a$ ia wrong in many sences: it gives the condition $\partial_\mu e_{\nu a}=\partial_\nu e_{\mu a}$, which leads us t

Thomas Jaeck, Joseph V. Pulé, Valentin Zagrebnov

We study the perfect Bose gas in random external potentials and show that there is generalized Bose-Einstein condensation in the random eigenstates if and only if the same occurs in the one-particle kinetic-energy eigenstates, which corresponds to the generalized condensation of the free Bose gas. Moreover, we prove that the amounts of both condensate densit

H. Morales

We study the gravity assist in the general case, i.e. when the spacecraft is not in a coplanar motion with respect to the planet&#39;s orbit. Our derivation is based on Kepler&#39;s planetary motion and Galilean addition of velocities, subjects covered in introductory physics courses. The main purpose of this paper is to illustrate how the gravity assist can

John R. Mahoney, Christopher J. Ellison, James P. Crutchfield

We give a systematic expansion of the crypticity--a recently introduced measure of the inaccessibility of a stationary process&#39;s internal state information. This leads to a hierarchy of k-cryptic processes and allows us to identify finite-state processes that have infinite crypticity--the internal state information is present across arbitrarily long, obs

E. Liflyand, R. Trigub

New sufficient conditions for representation of a function via the absolutely convergent Fourier integral are obtained in the paper. In the main result, Theorem 1.1, this is controlled by the behavior near infinity of both the function and its derivative. This result is extended to any dimension $d\ge2.$

E. G. Berezhko

The composition of the overall spectrum of cosmic rays (CRs) is studied under the assumption that ultra high energy CRs above the energy 10^{17} eV are produced at the shock created by the expanding cocoons around active galactic nuclei (AGNs). It is shown that the expected CR composition is characterised by two peaks in the energy dependence of the mean CR

Christopher M. Johns-Krull, Thomas P. Greene, Greg W. Doppmann, Kevin R. Covey

Strong stellar magnetic fields are believed to truncate the inner accretion disks around young stars, redirecting the accreting material to the high latitude regions of the stellar surface. In the past few years, observations of strong stellar fields on T Tauri stars with field strengths in general agreement with the predictions of magnetospheric accretion t

David Garofalo

We explore the connection between black hole spin and AGN power by addressing the consequences underlying the assumption in the recent literature that the gap region between accretion disks and black holes is fundamental in producing strong, spin-dependent, horizon-threading magnetic fields. Under the additional assumption that jets and outflows in AGN are p

A. Derevianko, B. Obreshkov, V. A. Dzuba

We explore a feasibility of measuring atom-wall interaction using atomic clocks based on atoms trapped in engineered optical lattices. Optical lattice is normal to the wall. By monitoring the wall-induced clock shift at individual wells of the lattice, one would measure a dependence of the atom-wall interaction on the atom-wall separation. We rigorously eval

The BABAR Collaboration, B. Aubert

We study the reaction e+e- --> e+e-pi0 and measure the gamma gamma* --> pi0 transition form factor in the momentum transfer range from 4 to 40 GeV^2. The analysis is based on 442 fb^-1 of integrated luminosity collected at PEP-II with the BABAR detector at e+e- center-of-mass energies near 10.6 GeV.

E. Piña

A new coordinate system is defined for the Four-Body dynamical problem with general masses, having as its origin of coordinates the center of mass. The transformation from the inertial coordinate system involves a combination of a rotation to the principal axis of inertia, followed by three changes of scale leading the principal moments of inertia to yield a

Lixin Xu, Jianbo Lu, Wenbo Li

In this paper, time variable cosmological constant, dubbed {\it age cosmological constant}, is investigated motivated by the fact: any cosmological length scale and time scale can introduce a cosmological constant or vacuum energy density into Einstein&#39;s theory. The age cosmological constant takes the form $ρ_Λ=3c^2M^2_P/t_Λ^2$, where $t_Λ$ is the age of

Ching Hung Lam, Hiroki Shimakura

In this paper, we study certain Virasoro frames for lattice vertex operator algebras and their $\Z_2$-orbifolds using linear codes over $\Z_4$. We also compute the corresponding frame stabilizer from the view point of binary codes and $\Z_4$-codes. As an application, we determine the frame stabilizers of several Virasoro frames of the vertex operator algebra

Emma Smith Zbarsky

We define homotopy group actions in terms of families of $A_\infty$ algebras indexed by a manifold M. We give explicit formulae for the $A_\infty$ morphism induced by a path on the manifold and for the $A_\infty$ homotopy corresponding to a pair of homotopic paths. Finally, we compute examples for finite groups and finitely generated free nonabelian groups a

Douglas Spolyar, Matthew Buckley, Katherine Freese, Dan Hooper

Recently, observations by PAMELA, the Fermi Gamma Ray Space Telescope, and other cosmic ray experiments have generated a great deal of interest in dark matter (DM) particles which annihilate at a high rate to leptons. In this letter, we explore the possibility of using large volume neutrino telescopes, such as IceCube, to constrain such models; specifically

Andrew M. Baxter

We apply ideas from the cluster method to q-count the permutations of a multiset according to the number of occurrences of certain generalized patterns, as defined by Babson and Steingrimsson. In particular, we consider those patterns with three letters and one internal dash, as well as permutation statistics composed of counting the number of occurrences of

A. Kulesza, L. Motyka

We study the effect of soft gluon emission in the hadroproduction of gluino-gluino and squark-antisquark pairs at the next-to-leading logarithmic (NLL) accuracy within the framework of the minimal supersymmetric model. We present the calculation of the one-loop soft anomalous dimension matrices controlling the colour evolution of the underlying hard-scatteri

Tobias Ulbricht, Peter Schmitteckert

We consider a one-dimensional chain consisting of an interacting area coupled to non-interacting leads. Within the area, interaction is mediated by a local on-site repulsion. Using real time evolution within the Density Matrix Renormalisation Group (DMRG) scheme, we study the dynamics of wave packets in this two-terminal transport setup. In contrast to previ

Christian W. Bauer, Bjorn O. Lange

The production of vector bosons in association with jets contains at least two unrelated scales. The first is the mass of the vector boson m_V and the second is the hard interaction scale giving rise to large transverse momenta of the produced jets. The production cross sections depend logarithmically on the ratio of these scales, which can lead to a poor co

M. Brueggen, E. Scannapieco

Cool cores of galaxy clusters are thought to be heated by low-power active galactic nuclei (AGN), whose accretion is regulated by feedback. However, the interaction between the hot gas ejected by the AGN and the ambient intracluster medium is extremely difficult to simulate as it involves a wide range of spatial scales and gas that is Rayleigh-Taylor (RT) un

Mir Ali, Frenny Ruiz, Carlos Saint-Victor, Justin F. Vazquez-Poritz

We consider the behavior of open strings on AdS wormholes in Gauss-Bonnet theory, which are the Gauss-Bonnet gravity duals of a pair of field theories. A string with both endpoints on the same side of the wormhole describes two charges within the same field theory, which exhibit Coulomb interaction for small separation. On the other hand, a string extending

Brian P. Sullivan, A. Bhattacharjee, Yi-Min Huang

This paper presents Sweet-Parker type scaling arguments in the context of hyper-resistive Hall magnetohyrdodynamics (MHD). The predicted steady state scalings are consistent with those found by Chac\'on et al. [PRL 99, 235001 (2007)], though as with that study, no prediction of electron dissipation region \emph{length} is made. Numerical experiments confirm

Elena Bruna

Jet fragmentation functions provide insight into jet structure and are expected to be modified by the nuclear medium in A+A collisions with respect to p+p reference measurements. If jet reconstruction is unbiased then a softening of the fragmentation functions is expected and should be observed in Au+Au collisions at RHIC. In these proceedings we present mea

Ian T. Durham

Birkhoff&#39;s Theorem states that doubly stochastic matrices are convex combinations of permutation matrices. Quantum mechanically these matrices are doubly stochastic channels, i.e. they are completely positive maps preserving both the trace and the identity. We expect these channels to be convex combinations of unitary channels and yet it is known that so

Jim Agler, N. J. Young

We give an elementary proof of Sarason&#39;s solvability criterion for the Nevanlinna-Pick problem with boundary interpolation nodes and boundary target values. We also give a concrete parametrization of all solutions of such a problem. The proofs are based on a reduction method due to Julia and Nevanlinna. Reduction of functions corresponds to Schur complem

Stephen P. Jordan, David Gosset, Peter J. Love

We show that finding the lowest eigenvalue of a 3-local symmetric stochastic matrix is QMA-complete. We also show that finding the highest energy of a stoquastic Hamiltonian is QMA-complete and that adiabatic quantum computation using certain excited states of a stoquastic Hamiltonian is universal. We also show that adiabatic evolution in the ground state of

Nicoleta Voicu-Brinzei, Sergey Siparov

Anisotropy of a space naturally leads to direction dependent electromagnetic tensors and electromagnetic potentials. Starting from this idea and using variational approaches and exterior derivative formalism, we extend some of the classical equations of electromagnetism to anisotropic (Finslerian) spaces. The results differ from the ones obtained by means of

Mark H. A. Davis, Sebastien Lleo

This paper considers a portfolio optimization problem in which asset prices are represented by SDEs driven by Brownian motion and a Poisson random measure, with drifts that are functions of an auxiliary diffusion &#39;factor&#39; process. The criterion, following earlier work by Bielecki, Pliska, Nagai and others, is risk-sensitive optimization (equivalent t

Kathryn M. G. Peek

We present a new technique for measuring the abundance of europium, a representative r-process element, in solar-metallicity stars. Our algorithm compares LTE synthetic spectra with high-resolution observational spectra using a chi-square-minimization routine. The analysis is fully automated, and therefore allows consistent measurement of blended lines even

Seokcheon Lee

Three decades ago Heath found the integral form of the exact analytic growing mode solution of linear density perturbation $δ$ in sub-horizon scales including the cosmological constant or the curvature term. Interestingly, we are able to obtain the analytic solution for general dark energy models with the constant equation of state $ω_{de}$. We compare the c

Petri Vaisanen, Jari K. Kotilainen, Mika Juvela, Kalevi Mattila

We present follow-up observations of the far-infrared (FIR) sources at 90, 150 and 180 mu detected as part of the ISOPHOT EBL project, which has recently measured the absolute surface brightness of the cosmic infrared background radiation (CIRB) for the first time independently from COBE data. We have observed the fields at the North Galactic Pole region in

D. Boyanovsky, R. Holman, Jimmy A. Hutasoit

We consider a sterile neutrino to be an unparticle, namely an \emph{unsterile neutrino}, with anomalous dimension $η$ and study its mixing with a canonical active neutrino via a see-saw mass matrix. We show that there is \emph{no unitary} transformation that diagonalizes the mixed propagator and a field redefinition is required. The propagating or ``mass&#39

Duncan Hanson, Kendrick M. Smith, Anthony Challinor, Michele Liguori

We study the effects of gravitational lensing on the estimation of non-Gaussianity from the bispectrum of the cosmic microwave background (CMB) temperature anisotropies. We find that the effect of lensing on the bispectrum may qualitatively be described as a smoothing of the acoustic features analogous to the temperature power spectrum. In contrast to previo

Gia-Wei Chern, Natalia Perkins

We present a novel approach to study the ground state and elementary excitations in compounds where spins and orbitals are entangled by on-site relativistic spin-orbit interaction. The appropriate degrees of freedom are localized states with an effective angular momentum J. We generalize J to arbitrary large values while maintaining the delicate spin-orbital

Patrick Draper, Tao Liu, Carlos E. M. Wagner

We analyze the Tevatron reach for neutral Higgs bosons in the Minimal Supersymmetric Standard Model (MSSM), using current exclusion limits on the Standard Model Higgs. We study four common benchmark scenarios for the soft supersymmetry-breaking parameters of the MSSM, including cases where the Higgs decays differ significantly from the Standard Model, and pr

Han Seek Kim, C. M. Baugh, S. Cole, C. S. Frenk

The clustering amplitude of galaxies depends on their intrinsic luminosity. We compare the properties of publicly available galaxy formation models with clustering measurements from the two-degree field galaxy redshift survey. The model predictions show the same qualitative behaviour as the data but fail to match the observations at the level of accuracy at

Asimina Arvanitaki, Savas Dimopoulos, Sergei Dubovsky, Nemanja Kaloper

String theory suggests the simultaneous presence of many ultralight axions possibly populating each decade of mass down to the Hubble scale 10^-33eV. Conversely the presence of such a plenitude of axions (an &#34;axiverse&#34;) would be evidence for string theory, since it arises due to the topological complexity of the extra-dimensional manifold and is ad h

Valentino Tosatti

We study adiabatic limits of Ricci-flat Kahler metrics on a Calabi-Yau manifold which is the total space of a holomorphic fibration when the volume of the fibers goes to zero. By establishing some new a priori estimates for the relevant complex Monge-Ampere equation, we show that the Ricci-flat metrics collapse (away from the singular fibers) to a metric on

Mehrdad Nojoumian, Timothy C. Lethbridge

This article aims at reengineering of PDF-based complex documents, where specifications of the Object Management Group (OMG) are our initial targets. Our motivation is that such specifications are dense and intricate to use, and tend to have complicated structures. Our objective is therefore to create an approach that allows us to reengineer PDF-based docume

Fatih Dogan, Lucian Covaci, Wonkee Kim, Frank Marsiglio

Magnetization reversal is a well-studied problem with obvious applicability in computer hard-drives. One can accomplish a magnetization reversal in at least one of two ways: application of a magnetic field, or through a spin current. The latter is more amenable to a fully quantum mechanical analysis. We formulate and solve the problem whereby a spin current

Shima Shimizu

An NLO QCD analysis on the HERA combined cross sections obtained from the measurements using the data up to the year 2000 at both the H1 and ZEUS collaborations provides significantly improved parton distribution functions. In 2007, HERA successfully operated with reduced center-of-mass energies. Direct measurements of F_L were performed at x\sim10^{-3}, giv

Charles De Clercq

Let $\mathbb{M}:=(M(X),p)$ be a direct summand of the motive associated with a geometrically split, geometrically variety over a field $F$ satisfying the nilpotence principle. We show that under some conditions on an extension $E/F$, if $\mathbb{M}$ is a direct summand of another motive $M$ over an extension $E$, then $\mathbb{M}$ is a direct summand of $M$

Christopher M. Drupieski, Daniel K. Nakano, Brian J. Parshall

The authors compute the support varieties of all irreducible modules for the small quantum group $u_ζ(\mathfrak{g})$, where $\mathfrak{g}$ is a simple complex Lie algebra, and $ζ$ is a primitive $\ell$-th root of unity with $\ell$ larger than the Coxeter number of $\mathfrak{g}$. The calculation employs the prior calculations and techniques of Ostrik and of

Erik Strahler

IceCube is a km^3 scale neutrino detector being constructed deep in the Antarctic ice. When complete, IceCube will consist of 4800 optical modules deployed on 80 strings between 1450 and 2450 m of depth. During the 2007-2008 data taking season, 22 strings were operational. This configuration is already much larger than previous neutrino telescopes and provid

Lorenzo Iorio

Many long-range modifications of the Newtonian/Einsteinian standard laws of gravity have been proposed in the recent past to explain various celestial phenomena occurring at different scales ranging from solar system to the entire universe. The most famous ones are the so-called Pioneer anomaly, {i.e.} a still unexplained acceleration detected in the telemet

Chrysostomos Kalousios, C. Vergu, Anastasia Volovich

AdS_4/CFT_3 duality relating IIA string theory on AdS_4 x CP^3 to N=6 superconformal Chern-Simons theory provides an arena for studying aspects of integrability in a new potentially exactly solvable system. In this paper we explore the tree-level worldsheet scattering for strings on AdS_4 x CP^3. We compute all bosonic four-, five- and six-point amplitudes i

A. E. Dorokhov

Experimental and theoretical progress concerning the rare decay π^0 \to e^+e^- is briefly reviewed. It includes the latest data from KTeV and a new model independent estimate of the decay branching which show the deviation between experiment and theory at the level of $3.3σ$. The predictions for ηand η&#39; decays into lepton pair are presented. We also comm

Wei Han, K. Pi, W. Bao, K. M. McCreary

Spin accumulation and spin precession in single-layer graphene are studied by non-local spin valve measurements at room temperature. The dependence of the non-local magnetoresistance on electrode spacing is investigated and the results indicate a spin diffusion length of ~1.6 microns and a spin injection/detection efficiency of 0.013. Electrical detection of

Carl Boone, Jordan Katine, Jeff Childress, Vasil Tiberkevich

We use spin torque ferromagnetic resonance to measure the spectral properties of dipole-exchange spin waves in permalloy nanowires. Our measurements reveal that geometric confinement has a profound effect on the damping of spin waves in the nanowire geometry. The damping parameter of the lowest-energy quantized spin wave mode depends on applied magnetic fiel

Jia-Wei Zhang, Zhen-Yun Fang, Chao-Hsi Chang, Xing-Gang Wu

We study the hadronic production of $B_s$ and $B_s^*$ mesons within the fixed-flavor-number scheme, in which the dominant gluon-gluon fusion mechanism is dealt with by using the complete $α_s^4$ approach. Main theoretical uncertainties for $B_s$ and $B_s^*$ production at TEVATRON and LHC are presented. It is found that when $m_s$ increases by steps of 0.1 Ge

C. Di Franco, D. Ballester

In the standard protocol for quantum teleportation, one assumes that Bob is able to perform ideal operations on his qubit. Here, we analyze the case in which some of these operations are more reliable than others. Moreover, we consider the channel shared by Alice and Bob as non-maximally entangled. In this context, the average fidelity of teleportation can b

Joseph Lorenzo Hall, Luke W. Miratrix, Philip B. Stark, Melvin Briones

Risk-limiting post-election audits limit the chance of certifying an electoral outcome if the outcome is not what a full hand count would show. Building on previous work, we report on pilot risk-limiting audits in four elections during 2008 in three California counties: one during the February 2008 Primary Election in Marin County and three during the Novemb

T. Ince

The measurement of Standard Model processes will be an important first step towards exploiting the discovery potential of the Large Hadron Collider, the highest energy accelerator ever built that will begin operation in the fall 2009. This paper presents a summary of the early physics analyses for understanding the performance of the detector as well as the

M. Martinez-Mares, A. Robledo

We exhibit a remarkable equivalence between the dynamics of an intermittent nonlinear map and the electronic transport properties (obtained via the scattering matrix) of a crystal defined on a double Cayley tree. This strict analogy reveals in detail the nature of the mobility edge normally studied near (not at) the metal-insulator transition in electronic s

Vasco Brattka, Guido Gherardi

In this paper we study a new approach to classify mathematical theorems according to their computational content. Basically, we are asking the question which theorems can be continuously or computably transferred into each other? For this purpose theorems are considered via their realizers which are operations with certain input and output data. The technica

Ivan Blanco

For a newform for Gamma_0(N) of even weight k, we prove that its attached p-adic L-function is not identically zero on the group Z_p of the p-adic units. If p >3, we prove that the order of vanishing at any p-adic integer is finite.

Björn Bäuchle, Marcus Bleicher

Direct photon emission in heavy-ion collisions is calculated within a relativistic micro+macro hybrid model and compared to the microscopic transport model UrQMD. In the hybrid approach, the high-density part of the evolution is replaced by an ideal 3-dimensional hydrodynamic calculation. This allows to examine the effects of viscosity and full local thermal

Vasco Brattka, Guido Gherardi

In this paper we study Weihrauch reducibility for multi-valued functions on represented spaces. We call the corresponding equivalence classes Weihrauch degrees and we show that the corresponding partial order induces a lower semi-lattice with the disjoint union of multi-valued functions as greatest lower bound operation. We prove that parallelization is a cl

Marie Martig, Frederic Bournaud, Romain Teyssier, Avishai Dekel

We point out a natural mechanism for quenching of star formation in early-type galaxies. It automatically links the color of a galaxy with its morphology and does not require gas consumption, removal or termination of gas supply. Given that star formation takes place in gravitationally unstable gas disks, it can be quenched when a disk becomes stable against

Bruno Bassetti, Mina Zarei, Marco Cosentino Lagomarsino, Ginestra Bianconi

The Pitman-Yor, or Chinese Restaurant Process, is a stochastic process that generates distributions following a power-law with exponents lower than two, as found in a numerous physical, biological, technological and social systems. We discuss its rich behavior with the tools and viewpoint of statistical mechanics. We show that this process invariably gives r

Jian-Rong Zhang, Ming-Qiu Huang

We systematically investigate the mass spectra of $\{Q\bar{s}\}\{\bar{Q}^{(&#39;)}s\}$ molecular states in the framework of QCD sum rules. The interpolating currents representing the molecular states are proposed. Technically, contributions of the operators up to dimension six are included in operator product expansion (OPE). The masses for molecular states

D. E. Postnov, F. Müller, R. B. Schuppner, L. Schimansky-Geier

According to the conventional approach to model neural ensembles the extracellular environment has fixed ionic concentrations. However, in many cases the extracellular concentration of potassium ions can not be regarded as constant. That represents specific chemical pathway for neurons to interact and can influence strongly the behavior of a single neuron as