April 2009 arXiv papers — page 17

Jarod Alper

We study the local properties of Artin stacks and their good moduli spaces, if they exist. We show that near closed points with linearly reductive stabilizer, Artin stacks formally locally admit good moduli spaces. We also give conditions for when the existence of good moduli spaces can be deduced from the existence of etale charts admitting good moduli spac

Ana Peón-Nieto

We study the differential Galois theory of difference equations under weaker hypothesis on the field of constants of the automorphism. This framework yields a new approach to results by C.Hardouin and M.Singer, which answers possitively a question by M.Singer: under the classical hypothesis, the known results are still valid. In particular, our Galois group

Yoav Freund

We present a method for hedging in continuous time.

Mark Gross, Sorin Popescu

This is the sequel to arXiv:math/0001089. In this paper, we complete the promised description of moduli of abelian surfaces of low degree, covering the cases of degree (1,12), (1,14), (1,16), (1,18) and (1,20). In each case, we describe birational models for the moduli space of abelian surfaces with polarization of the given degree and either a level structu

Kiumars Kaveh, A. G. Khovanskii

Generalizing the notion of Newton polytope, we define the Newton-Okounkov body, respectively, for semigroups of integral points, graded algebras, and linear series on varieties. We prove that any semigroup in the lattice Z^n is asymptotically approximated by the semigroup of all the points in a sublattice and lying in a convex cone. Applying this we obtain s

Abolfazl Bayat, Pasquale Sodano, Sougato Bose

We study the entanglement of an impurity at one end of a spin chain with a block of spins using negativity as a true measure of entanglement to characterize the unique features of the gapless Kondo regime in the spin chain Kondo model. For this spin chain in the Kondo regime we determine- with a true entanglement measure- the spatial extent of the Kondo scre

Karola Meszaros

The type C_n full root polytope is the convex hull in R^n of the origin and the points e_i-e_j, e_i+e_j, 2e_k for 1 <= i < j <= n, k \in [n]. Given a graph G, with edges labeled positive or negative, associate to each edge e of G a vector v(e) which is e_i-e_j if e=(i, j), i < j, is labeled negative and e_i+e_j if it is labeled positive. For such a signed gr

Yves Pierseaux

We show that Cosmological Constant (CC) is not optional in GR (General Relativity) because it is required by SR (Special Relativity). This completely unexpected result is obtained by introducing a minimal acceleration (Milgrom), square root of CC, in Einstein boost with Lorentz Transformation (LT). We prove that hyperbolic rotation (LT) is an hyperbolic moti

De-Chang Dai, Katherine Freese, Dejan Stojkovic

In order to accommodate increasingly tighter observational constraints on dark matter, several models have been proposed recently in which dark matter particles are charged under some hidden gauge group. Hidden gauge charges are invisible for the standard model particles, hence such scenarios are very difficult to constrain directly. However black holes are

V. V. Mkhitaryan, E. G. Mishchenko, M. E. Raikh, L. I. Glazman

Opening of a gap in the low-energy excitations spectrum affects the power-law singularity in the photon absorption spectrum $A(Ω)$. In the normal state, the singularity, $A(Ω)\propto [D/(Ω-Ω_{\rm th})]^α$, is characterized by an interaction-dependent exponent $α$. On the contrary, in the supeconducting state the divergence, $A(Ω)\propto (D/Δ)^α(Ω-\tildeΩ_{\r

Michael Ummels, Dominik Wojtczak

We analyse the computational complexity of finding Nash equilibria in stochastic multiplayer games with $ω$-regular objectives. While the existence of an equilibrium whose payoff falls into a certain interval may be undecidable, we single out several decidable restrictions of the problem. First, restricting the search space to stationary, or pure stationary,

Evgenya Shkolnik, Michael C. Liu, I. Neill Reid

We have completed a high-resolution (R=60,000) optical spectroscopic survey of 185 nearby M dwarfs identified using ROSAT data to select active, young objects with fractional X-ray luminosities comparable to or greater than Pleiades members. Our targets are drawn from the NStars 20-pc census and the Moving-M sample with distances determined from parallaxes o

A. G. Bedregal, L. Colina, A. Alonso-Herrero, S. Arribas

We present a study of the central 2.3 kpc of NGC 5135, a nearby Luminous Infrared Galaxy (LIRG) with an AGN and circumnuclear starburst. Our main results are based on intermediate spectral resolution (~ 3000-4000) near infrared data taken with the SINFONI integral field spectrograph at the ESO VLT. The ionization of the different phases of the interstellar g

X. S. Xu, Q. -C. Sun, J. L. Musfeldt

We present an application of the Lorentz model in which fits to vibrational spectra or a Kramers Kronig analysis are employed along with several useful formalisms to quantify microscopic charge in unoriented (powdered) materials. The conditions under which these techniques can be employed are discussed, and we analyze the vibrational response of a layered tr

Jonathan J. Heckman, Cumrun Vafa

Recent work on F-theory GUTs has shown that the predicted masses, and magnitudes of the mixing matrix elements in the quark and lepton sectors are in close accord with experiment. In this note we estimate the CP violating phase of the mixing matrices by considering the Jarlskog invariant. We find by carefully treating certain cancellations in the computation

Joel C Miller

The social networks that infectious diseases spread along are typically clustered. Because of the close relation between percolation and epidemic spread, the behavior of percolation in such networks gives insight into infectious disease dynamics. A number of authors have studied clustered networks, but the networks often contain preferential mixing between h

T. Di Salvo, A. D&#39;Ai&#39;, R. Iaria, L. Burderi

Iron emission lines at 6.4-6.97 keV, identified with fluorescent Kalpha transitions, are among the strongest discrete features in the X-ray band. These are therefore one of the most powerful probes to infer the properties of the plasma in the innermost part of the accretion disc around a compact object. In this paper we present a recent XMM observation of th

F. R. Klinkhamer

It has been suggested recently to study the dynamics of a gravitating gluon condensate q in the context of a spatially flat Friedmann-Robertson-Walker universe. The expansion of the Universe (or, more generally, the presence of a nonvanishing Ricci curvature scalar R) perturbs the gluon condensate and may induce a nonanalytic term \tilde{h}(R,q) in the effec

Gabor Zsolt Toth

The problem of extending quantum-mechanical formal scattering theory to a more general class of models that also includes quantum field theories is discussed, with the aim of clarifying certain aspects of the definition of scattering states. As the strong limit is not suitable for the definition of scattering states in quantum field theory, some other limiti

Hooman Davoudiasl

Two general problems arise when interpreting the recent cosmic ray data as signals of Dark Matter (DM) annihilation: (i) the required cross section is too large by O(100), and (ii) the annihilation products seem to be mostly leptonic. We propose to address these two problems by assuming that the couplings of DM to leptons grow with time. This can be achieved

A. A. Radovskaya, E. A. Kuraev

We calculate the radiative corrections to the annihilation of the Dark Matter particles into leptons. Lepton masses are taken into account. As the Dark Matter particles are considered both Dirac and Majorana fermions. We sum up all the leading logarithms contributions where it is possible. We show that in the Dirac fermion case the resulting cross-section is

M. Gmitra, S. Konschuh, C. Ertler, C. Ambrosch-Draxl

The electronic band structure of graphene in the presence of spin-orbit coupling and transverse electric field is investigated from first principles using the linearized augmented plane-wave method. The spin-orbit coupling opens a gap at the $K(K&#39;)$-point of the magnitude of 24 $μ$eV (0.28 K). This intrinsic splitting comes 96% from the usually neglected

A. Gehrmann-De Ridder, M. Ritzmann

We present an extension of the antenna subtraction formalism at NLO to include massive final state fermions. The basic ingredients to the subtraction terms, the NLO massive final-final antenna functions are derived and integrated over the corresponding factorised phase space. Those antenna functions account for all soft, collinear and quasi-collinear limits

C. -A. Faucher-Giguere, Abraham Loeb

We estimate the contribution of Galactic pulsars, both ordinary and millisecond pulsars (MSPs), to the high-energy (>100 MeV) gamma-ray background. We pay particular attention to the high-latitude part of the background that could be confused with an extragalactic component in existing analyses that subtract a Galactic cosmic-ray model. Our pulsar population

Hassan Dadashi-Arani, Bijan Z. Zangeneh

We demonstrate the large deviation property for the mild solutions of stochastic evolution equations with monotone nonlinearity and multiplica- tive noise. This is achieved using the recently developed weak convergence method, in studying the large deviation principle. An It^o-type inequality is a main tool in the proofs. We also give two examples to illustr

Matthias Blau, Jelle Hartong, Blaise Rollier

We study various geometrical aspects of Schroedinger space-times with dynamical exponent z>1 and compare them with the properties of AdS (z=1). The Schroedinger metrics are singular for 1<z<2 while the usual Poincare coordinates are incomplete for z \geq 2. For z=2 we obtain a global coordinate system and we explain the relations among its geodesic completen

Xin-Zhong Yan, Yousef Romiah, C. S. Ting

On the basis of self-consistent Born approximation for Dirac fermions under charged impurity scatterings in graphene, the theory for calculating the thermo-electric power is developed by using the heat current-current correlation function. The advantage of the present approach is its ability to effectively treat the low doping case where the coherence proces

Sean M. Carroll, Matthew C. Johnson, Lisa Randall

We show that D-dimensional de Sitter space is unstable to the nucleation of non-singular geometries containing spacetime regions with different numbers of macroscopic dimensions, leading to a dynamical mechanism of compactification. These and other solutions to Einstein gravity with flux and a cosmological constant are constructed by performing a dimensional

Enrique Álvarez, Antón F. Faedo, J. J. López-Villarejo

Theories of gravity invariant under those diffeomorphisms generated by transverse vectors, $\pd_\mξ^\m=0$ are considered. Such theories are dubbed transverse, and differ from General Relativity in that the determinant of the metric, $g$, is a transverse scalar. We comment on diverse ways in which these models can be constrained using a variety of observation

T. Ferrus, D. G. Hasko, Q. R. Morrissey, S. R. Burge

We present a realisation of high bandwidth instrumentation at cryogenic temperatures and for dilution refrigerator operation that possesses advantages over methods using radio-frequency single electron transistor or transimpedance amplifiers. The ability for the low temperature electronics to carry out faster measurements than with room temperature electroni

G. Pace, J. Melendez, L. Pasquini, G. Carraro

Chromospheric activity is widely used as an age indicator for solar-type stars based on the early evidence that there is a smooth evolution from young and active to old and inactive stars. We analysed chromospheric activity in five solar-type stars in two open clusters, in order to study how chromospheric activity evolves with time. We took UVES high-resolut

Sung Seok A. Seo, Ho Nyung Lee

We report on growth and ferroelectric (FE) properties of superlattices (SLs) composed of the FE BaTiO3 and the paraelectric (PE) CaTiO3. Previous theories have predicted that the polarization in (BaTiO3)n/(CaTiO3)n SLs increases as the sublayer thickness (n) increases when the same strain state is maintained. However, our BaTiO3/CaTiO3 SLs show a varying lat

Javier Grande, Ana Pelinson, Joan Sola

We analyze some generic properties of the dark energy (DE) perturbations, in the case of a self-conserved DE fluid. We also apply a simple test (the &#34;F-test&#34;) to compare a model to the data on large scale structure (LSS) under the assumption of negligible DE perturbations. We exemplify our discussions by means of the LXCDM model, showing that it prov

Vincent P. A. Lonij, William F. Holmgren, Alexander D. Cronin

We report improved precision measurements of the Van der Waals potential strength ($C_3$) for Na atoms and a silicon-nitride (SiN$_x$) surface. We studied diffraction from nano-fabricated gratings with a particular &#34;magic&#34; open-fraction that allows us to determine $C_3$ without the need for separate measurements of the width of the grating openings.

Sumei Huang, G. S. Agarwal

We study how an optical parametric amplifier inside the cavity can affect the normal mode splitting behavior of the coupled movable mirror and the cavity field. We work in the resolved sideband regime. The spectra exhibit a double-peak structure as the parametric gain is increased. Moreover, for a fixed parametric gain, the double-peak structure of the spect

Steven Willison

In four space-time dimensions, there are good theoretical reasons for believing that General Relativity is the correct geometrical theory of gravity, at least at the classical level. If one admits the possibility of extra space-time dimensions, what would we expect classical gravity to be like? It is often stated that the most natural generalisation is Lovel

Hao Fang, Mijia Lai, Xinan Ma

In this paper, we study a class of fully nonlinear metric flow on Kähler manifolds, which includes the J-flow as a special case. We provide a sufficient and necessary condition for the long time convergence of the flow, generalizing the result of Song-Weinkove. As a consequence, under the given condition, we solved the corresponding Euler equation, which is

C. Grillo, R. Gobat, M. Lombardi, P. Rosati

By using the SDSS multicolor photometry and lens modeling, we study stellar mass properties and the luminous and dark matter composition of the 57 early-type lens galaxies analyzed by the SLACS Survey. We fit the lens SEDs composed of ugriz magnitudes with a three-parameter grid of different composite stellar population models, computed by adopting solar met

Francesco Lemma

We construct a norm compatible system of Galois cohomology classes in the cyclotomic extension of the field of rationnals giving rise (conjecturally) to the degree four p-adic L-function of the symplectic group GSp(4). These classes are defined as cup products of torsion sections of the elliptic polylogarithm pro-sheaf. We rely on the norm compatibility of t

Neil V. Budko

The first principles analysis of the radiation by an arbitrary source in a flat Friedmann-Robertson-Walker space-time is presented. The obtained analytical solution explicitly shows that the cosmological redshift is not of kinematic origin and that the source and the observer may be regarded as being at rest with respect to eachother at all times. At the sam

John S. Hamel

This paper discusses how to implement certain classes of quantum computer algorithms using classical discrete switching networks that are amenable to implementation in main stream CMOS transistor IC technology. The methods differ from other classical approaches in that asynchronous feedback is exploited in classical transistor reversible logic circuits to im

S. Cawston, L. Vostrikova

For a converging sequence of exponential L\'evy models, we give conditions under which the associated sequence of option prices converges. We also study the behaviour of the prices when no such convergence holds. We then consider two special cases, first when the martingale measure is chosen by minimisation of entropy and then when it minimises Hellinger int

Boncho P. Bonev, Michael J. Mumma, Erika L. Gibb, Michael A. Disanti

High-dispersion (l/dl ~ 25,000) infrared spectra of Comet C/2004 Q2 (Machholz) were acquired on Nov. 28-29, 2004, and Jan. 19, 2005 (UT dates) with NIRSPEC at the Keck-2 telescope on Mauna Kea. We detected H2O, CH4, C2H2, C2H6, CO, H2CO, CH3OH, HCN, and NH3 and we conducted a sensitive search for CH3D. We report rotational temperatures, production rates, and

Sjoerd Dirksen, Marcel de Jeu, Marten Wortel

Let X be a non-degenerate left Banach module over a normed algebra A having a bounded approximate left identity. We show that, if A is a left ideal of a larger algebra, then this representation can be extended to a representation of the larger algebra. Based on this result, we study in detail the existence and properties of representations of the various cen

Michio Otsuki, Hisao Hayakawa

Critical behaviors of sheared dense and frictionless granular materials in the vicinity of the jamming transition are numerically investigated. From the extensive molecular dynamics simulation, we verify the validity of the scaling theory near the jamming transition proposed by Otsuki and Hayakawa (Prog. Theor. Phys., 121, 647 (2009)). We also clarify the cr

Thomas Lévèque, A. Gauguet, Franck Michaud, Franck Pereira Dos Santos

IIn this paper we demonstrate a new scheme for Raman transitions which realize a symmetric momentum-space splitting of $4 \hbar k$, deflecting the atomic wave-packets into the same internal state. Combining the advantages of Raman and Bragg diffraction, we achieve a three pulse state labelled interferometer, intrinsically insensitive to the main systematics

Christoph-Marian Goletz, Frank Grossmann, Steven Tomsovic

Quantized systems whose underlying classical dynamics possess an elaborate mixture of regular and chaotic motion can exhibit rather subtle long-time quantum transport phenomena. In a short wavelength regime where semiclassical theories are most relevant, such transport phenomena, being quintessentially interference based, are difficult to understand with the

G. Costakis, D. Hadjiloucas, A. Manoussos

In this paper we extend the notion of a locally hypercyclic operator to that of a locally hypercyclic tuple of operators. We then show that the class of hypercyclic tuples of operators forms a proper subclass to that of locally hypercyclic tuples of operators. What is rather remarkable is that in every finite dimensional vector space over $\mathbb{R}$ or $\m

Thierry Champel, Serge Florens

Motivated by high-accuracy scanning tunneling spectroscopy measurements on disordered two-dimensional electron gases in strong magnetic field, we present an exact solution for the local density of states (LDoS) of electrons moving in an arbitrary potential smooth on the scale of the magnetic length, that can be locally described up to its second derivatives.

A. Rabhi, C. Providencia, J. Da Providencia

We study the influence of the isovector-scalar meson on the spinodal instabilities and the distillation effect in asymmetric non-homogenous nuclear matter under strong magnetic fields, of the order of $10^{18}-10^{19}$ G. Relativistic nuclear models both with constant couplings (NLW) and with density dependent parameters (DDRH) are considered. A strong magne

Markus Schlapps, Teresa Lermer, Stefan Geissler, Daniel Neumaier

We report on magnetotransport measurements of nanoconstricted (Ga,Mn)As devices showing very large resistance changes that can be controlled by both an electric and a magnetic field. Based on the bias voltage and temperature dependent measurements down to the millikelvin range we compare the models currently used to describe transport through (Ga,Mn)As nanoc

S. Ashhab, J. Q. You, Franco Nori

We analyze the information that one can learn about the state of a quantum two-level system, i.e. a qubit, when probed weakly by a nearby detector. In particular, we focus on the case when the qubit Hamiltonian and the qubit&#39;s operator being probed by the detector do not commute. Because the qubit&#39;s state keeps evolving while being probed and because

Alberto Torchinsky

We solve the Cauchy problem for the $n$-dimensional wave equation using elementary properties of the Fourier transform.

Jonas Nyvold Pedersen, Andreas Wacker

Transport through nanosystems is treated within the second order von Neumann approach. This approach bridges the gap between rate equations which neglect level broadening and cotunneling, and the transmission formalism, which is essentially based on the single-particle picture thereby treating many-particle interactions on an approximate level. Here we provi

C. Fedeli, L. Moscardini, S. Matarrese

We predict the biasing and clustering properties of galaxy clusters that are expected to be observed in the catalogues produced by two forthcoming X-ray and Sunyaev-Zel&#39;dovich effect surveys. We study a set of flat cosmological models where the primordial density probability distribution shows deviations from Gaussianity in agreement with current observa

D. S. Carman, B. A. Raue

Beam-recoil transferred polarizations for the exclusive $\vec{e}p \to e'K^+ \vec{\Lambda},\vec{\Sigma}^0$ reactions have been measured using the CLAS spectrometer at Jefferson Laboratory. New measurements have been completed at beam energies of 4.261 and 5.754 GeV that span a range of momentum transfer $Q^2$ from 0.7 to 5.4 GeV$^2$, invariant energy $W$ from

J. -M. Barbaroux, J. -C. Guillot

We consider a Hamiltonian with cutoffs describing the weak decay of spin one massive bosons into the full family of leptons. The Hamiltonian is a self-adjoint operator in an appropriate Fock space with a unique ground state. We prove a Mourre estimate and a limiting absorption principle above the ground state energy and below the first threshold for a suffic

Xiao-song Ma, Angie Qarry, Johannes Kofler, Thomas Jennewein

We demonstrate hybrid entanglement of photon pairs via the experimental violation of a Bell inequality with two different degrees of freedom (DOF), namely the path (linear momentum) of one photon and the polarization of the other photon. Hybrid entangled photon pairs are created by Spontaneous Parametric Down Conversion and coherent polarization to path conv

Pascal Moyal

We propose an explicit construction of the solution of a stationary stochastic recursion of the form $X\circθ=ϕ(X)$ on a semi-ordered Polish space, when the monotonicity of $ϕ$ is not assumed. This solution exists on an enriched probability space (it is said \emph{weak}), provided the recursion is lattice-valued, and dominated by a proper monotonic stochasti

Michael Huber

This paper takes a significant step towards confirming a long-standing and far-reaching conjecture of Peter J. Cameron and Cheryl E. Praeger. They conjectured in 1993 that there are no non-trivial block-transitive 6-designs. We prove that the Cameron-Praeger conjecture is true for the important case of non-trivial Steiner 6-designs, i.e. for 6-$(v,k,\lambda)

David Chavalarias, Jean-Philippe Cointet

We are facing a real challenge when coping with the continuous acceleration of scientific production and the increasingly changing nature of science. In this article, we extend the classical framework of co-word analysis to the study of scientific landscape evolution. Capitalizing on formerly introduced science mapping methods with overlapping clustering, we

P. Roura Bas, A. A. Aligia

We study the Anderson model in which a configuration with a doublet is hybridized with another with a singlet and a triplet. We calculate the conductance through the system as a function of temperature and bias voltage, near the quantum critical line for which the system is exactly solvable. The results explain recent transport measurements in a single-molec

Thomas R. Weikl

The folding dynamics of small single-domain proteins is a current focus of simulations and experiments. Many of these proteins are 'two-state folders', i.e. proteins that fold rather directly from the denatured state to the native state, without populating metastable intermediate states. A central question is how to characterize the instable, partially folde

Takayuki Miyadera, Hideki Imai

This paper discusses the no-cloning theorem in a logico-algebraic approach. In this approach, an orthoalgebra is considered as a general structure for propositions in a physical theory. We proved that an orthoalgebra admits cloning operation if and only if it is a Boolean algebra. That is, only classical theory admits the cloning of states. If unsharp propos

Vladimir Sudilovsky, Donald Smith, Sandra Savaglio

There is nearly a factor of four difference in the number density of intervening MgII absorbers as determined from gamma-ray burst (GRB) and quasar lines of sight. We use a Monte-Carlo simulation to test if a dust extinction bias can account for this discrepancy. We apply an empirically determined relationship between dust column density and MgII rest equiva

Ayres Freitas, Frank Daniel Steffen, Nurhana Tajuddin, Daniel Wyler

Considering axino cold dark matter scenarios with a long-lived charged slepton, we study constraints on the Peccei-Quinn scale f_a and on the reheating temperature T_R imposed by the dark matter density and by big bang nucleosynthesis (BBN). For an axino mass compatible with large-scale structure, m_axino \gtrsim 100 keV, temperatures above 10^9 GeV become v

Vladimir Gritsev, Timofei Rostunov, Eugene Demler

In this paper we study nonequilibrium dynamics of one dimensional Bose gas from the general perspective of dynamics of integrable systems. After outlining and critically reviewing methods based on inverse scattering transform, intertwining operators, q-deformed objects, and extended dynamical conformal symmetry, we focus on the form-factor based approach. Mo

Alexander Grüneis, Kurt Kummer, Denis V. Vyalikh

Applying time-dependent photoemission we unravel the graphene growth process on a metallic surface by chemical vapor deposition (CVD). Graphene CVD growth is in stark contrast to the standard growth process of two--dimensional films because it is self-limiting and stops as soon as a monolayer graphene has been synthesized. Most importantly, a novel phase of

Dawood Kothawala, L. Sriramkumar, S. Shankaranarayanan, T. Padmanabhan

The hypothesis of path integral duality provides a prescription to evaluate the propagator of a free, quantum scalar field in a given classical background, taking into account the existence of a fundamental length, say, the Planck length, $\lp$, in a {\it locally Lorentz invariant manner}. We use this prescription to evaluate the duality modified propagators

Aldo J. Lazar

For $C^*$-algebras $A_1, A_2$ the map $(I_1,I_2)\to ker(q_{I_1}\otimes q_{I_2})$ from $Id^{\prime}(A_1)\times Id^{\prime}(A_2)$ into $Id^{\prime}(A_1\otimes_{\mathrm{min}} A_2) is a homeomorphism onto its image which is dense in the range. Here, for a $C^*$-algebra $A$, the space of all proper closed two sided ideals endowed with an adequate topology is deno

Anand Pal, Arpita Vajpayee, R. S. Meena, H. Kishan

We report synthesis, structural details and transport measurements on Sr4V2O6Fe2As2. Namely the stoichiometric amounts of V2O5 + SrO2 + Sr + 2FeAs are weighed mixed, ground thoroughly and palletized in rectangular form in a glove box in high purity Ar atmosphere. The pellet is further sealed in an evacuated (10-5 Torr) quartz tube and put for heat treatments

COMPASS Collaboration, M. Alekseev

The gluon polarisation in the nucleon has been determined by detecting charm production via D0 meson decay to charged K and pi in polarised muon scattering off a longitudinally polarised deuteron target. The data were taken by the COMPASS Collaboration at CERN between 2002 and 2006 and corresponds to an integrated luminosity of 2.8 fb^-1. The dominant underl

Xing-Gang Wu, Zhen-Yun Fang

Dominant spin-flip effects for the direct and prompt $J/ψ$ polarizations at TEVATRON run II with collision energy 1.96 TeV and rapidity cut $|y^{J/ψ}|<0.6$, have been systematically studied, especially, the spin-flip effect for the transition of $(c\bar{c})_8[^3S_1]$ into $J/ψ$ has been carefully discussed. It is found that the spin-flip effect shall always

Zhi-zhong Xing

Current experimental data indicate that two unitarity triangles of the CKM quark flavor mixing matrix V are almost the right triangles with α\approx 90^\circ. We find that α= 90^\circ actually points to {\rm Re}(V_{tb}V_{ud}V^*_{td}V^*_{ub}) = 0. Considering a very suggestive parametrization of V, we show that its CP-violating phase ϕis nearly equal to α(i.e

Bijan Sahamie

We derive a new exact sequence in the hat-version of Heegaard Floer homology. As a consequence we see a functorial connection between the invariant of Legendrian knots and the contact element. As an application we derive two vanishing results of the contact element making it possible to easily read off its vanishing out of a surgery presentation in suitable

Eduardo Guendelman, Alexander Kaganovich, Emil Nissimov, Svetlana Pacheva

The Einstein-Rosen &#34;bridge&#34; wormhole solution proposed in the classic paper [1] does not satisfy the vacuum Einstein equations at the wormhole throat. We show that the fully consistent formulation of the original Einstein-Rosen &#34;bridge&#34; requires solving Einstein equations of bulk D=4 gravity coupled to a lightlike brane with a well-defined wo

Erdal Celal Oğuz, René Messina, Hartmut Löwen

The crystalline ground state of macroions confined between two neutral parallel plates in the presence of their homogeneously spread counterions is calculated by lattice-sum minimization of candidate phases involving up to six layers. For increasing macroion density, a cascade of solid-solid transitions is found involving various multilayered crystals. The c

Yoshihiro Yunomae, Daisuke Yamamoto, Ippei Danshita, Nobuhiko Yokoshi

We study the stability of superfluid Fermi gases in deep optical lattices in the BCS--Bose-Einstein condensation (BEC) crossover at zero temperature. Within the tight-binding attractive Hubbard model, we calculate the spectrum of the low-energy Anderson-Bogoliubov (AB) mode as well as the single-particle excitations in the presence of superfluid flow in orde

Ben D. MacArthur, Rubén J. Sánchez-García

Many real-world complex networks contain a significant amount of structural redundancy, in which multiple vertices play identical topological roles. Such redundancy arises naturally from the simple growth processes which form and shape many real-world systems. Since structurally redundant elements may be permuted without altering network structure, redundanc

Germano D&#39;Abramo

In this Letter we describe a vacuum spherical capacitor that generates a macroscopic voltage between its spheres harnessing the heat from a single thermal reservoir at room temperature. The basic idea is trivial and it makes use of two concentric spherical electrodes with different work functions. We provide a mathematical analysis of the underlying physical

J. Bolmont, R. Buehler, A. Jacholkowska, S. J. Wagner

Highly energetic, variable and distant sources such as Active Galactic Nuclei provide a good opportunity to evaluate effects due to the emission and the propagation of high energy photons. In this note, a study of possible energy-dependent time-lags with PKS 2155-304 light curve as measured by H.E.S.S. in July 2006 is presented. These time-lags could either

Naoyuki Haba, Yutaka Sakamura, Toshifumi Yamashita

The scattering amplitude for the longitudinal weak bosons is investigated in the SU(3) gauge-Higgs unification as a function of the scattering energy, the Wilson line phase θ_H and the warp factor. The θ_H-dependence of the amplitude is quite different in the flat and the warped spacetimes. Generically the amplitude is enhanced for θ_H=O(1) in the warped cas

T. Sonoda, T. E. Cocolios, J. Gentens, M. Huyse

The proof of principle of the Laser Ion Source Trap (LIST) coupled to a gas cell catcher system has been demonstrated at the Leuven Isotope Separator On-Line (LISOL). The experiments were carried out by using the modified gas cell-based laser ion source and the SextuPole Ion Guide (SPIG). Element selective resonance laser ionization of neutral atoms was taki

Yoichi Kamihara, Takatoshi Nomura, Masahiro Hirano, Jung Eun Kim

A crystallographic and magnetic phase diagram of SmFeAsO1-xFx is determined as a function of x in terms of temperature based on electrical transport and magnetization, synchrotron powder x-ray diffraction, 57Fe Mossbauer spectra (MS), and 149Sm nuclear resonant forward scattering (NRFS) measurements. MS revealed that the magnetic moments of Fe were aligned a

L. Xiao, W. Reich, E. Fürst, J. L. Han

Many physical properties of this SNR such as spectrum and polarization can only be investigated by radio observations. The $λ$11 cm and $λ$6\ cm continuum and polarization observations of SNR G65.2+5.7 were made with the Effelsberg 100-m and the Urumqi 25-m telescopes, respectively, to investigate the integrated spectrum, the spectral index distribution, and

Matthieu Romagny

Let $R$ be a discrete valuation ring with fraction field $K$ and $X$ a flat $R$-scheme. Given a faithful action of a $K$-group scheme $G_K$ over the generic fibre $X_K$, we study models $G$ of $G_K$ acting on $X$. In various situations, we prove that if such a model $G$ exists, then there exists another model $G&#39;$ that acts faithfully on $X$. This model

Daewon Chung

This paper has been withdrawn by the author due to some error in the result

Martin Kassabov, Mark Sapir

The aim of this note is to answer a question by Guoliang Yu of whether the group $EL_3(Z<x,y>)$, where $Z<x,y>$ is the free (non-commutative) ring, has any faithful linear representations over a field. We prove, in particular, that for every (unitary associative) ring $R$, the group $EL_3(R)$ has a faithful finite dimensional complex representation if and on

K. Hebeler, T. Duguet, T. Lesinski, A. Schwenk

We study 1S0 pairing gaps in neutron and nuclear matter as well as in finite nuclei on the basis of microscopic two-nucleon interactions. Special attention is paid to the consistency of the pairing interaction and normal self-energy contributions. We find that pairing gaps obtained from low-momentum interactions depend only weakly on approximation schemes fo

Hisao Taira, Hiroyuki Shima

We describe the effects of geometric torsion on the coherent motion of electrons along a thin twisted quantum ring. The geometric torsion inherent in the quantum ring triggers a quantum phase shift in the electrons&#39; eigenstates, thereby resulting in a torsion-induced persistent current that flows along the twisted quantum ring. The physical conditions re

Thomas Schaefer, Derek Teaney

Shear viscosity is a measure of the amount of dissipation in a simple fluid. In kinetic theory shear viscosity is related to the rate of momentum transport by quasi-particles, and the uncertainty relation suggests that the ratio of shear viscosity eta to entropy density s in units of hbar/k_B is bounded by a constant. Here, hbar is Planck&#39;s constant and

Neil Smith

The mechanism of spin-pumping, described by Tserkovnyak et al., is formally analyzed in the general case of a magnetic multilayer consisting of two or more metallic ferromagnetic (FM) films separated by normal metal (NM) layers. It is shown that the spin-pumping-induced dynamic coupling between FM layers modifies the linearized Gilbert equations in a way tha

Sanjiban Santra, Juncheng Wei

We consider homoclinic solutions of fourth order equations $$ u^{&#34;&#34;} + β^2 u^{&#34;} + V_u (u)=0 {in} \R ,$$ where $V(u)$ is either the suspension bridge type $V(u)=e^u-1-u$ or Swift-Hohenberg type $ V(u)= {1/4}(u^2-1)^2$. For the suspension bridge type equation, we prove existence of a homoclinic solution for {\em all} $ β\in (0, β_*)$ where $ β_{*}

Konstantin Batygin, Gregory Laughlin, Stefano Meschiari, Eugenio Rivera

We investigate the possibility that the large orbital eccentricity of the transiting Neptune-mass planet Gliese 436b is maintained in the face of tidal dissipation by a second planet in the system. We find that the currently observed configuration can be understood if Gliese 436b and a putative companion have evolved to a quasi-stationary fixed point in whic

Lei Wang, Yanpeng Qi, Xianping Zhang, Zhaoshun Gao

The effect of Ag addition (0-20 wt%) on polycrystalline Sr0.6K0.4Fe2As2 superconductor has been investigated. It is found that the critical transition temperature Tc was not depressed, and the irreversibility field Hirr and hysteresis magnetization were significantly enhanced upon Ag addition. Characterization study reveals that larger grains are observed in

U. Trittmann, S. Pinsky

We show that adding a vacuum expectation value to a gauge field left over from a dimensional reduction of three-dimensional pure supersymmetric Yang-Mills theory generates mass terms for the fundamental fields in the two-dimensional theory while supersymmetry stays intact. This is similar to the adjoint mass term that is generated by a Chern-Simons term in t

A. S. Erickson, N. P. Breznay, E. A. Nowadnick, T. H. Geballe

Recent evidence for a charge-Kondo effect in superconducting samples of Pb$_{1-x}$Tl$_x$Te [1] has brought renewed attention to the possibility of negative U superconductivity in this material, associated with valence fluctuations on the Tl impurity sites [2]. Here, we use indium as an electron-donor to counterdope Pb$_{.99}$Tl$_{.01}$Te and study the effect

Laurent Proville

The present work is essentially concerned with the development of statistical theory for the low temperature dislocation glide in concentrated solid solutions where atom-sized obstacles impede plastic flow. In connection with such a problem, we compute analytically the external force required to drag an elastic string along a discrete two-dimensional square

Nathan Wiebe, Parin Sripakdeevong, Arnaldo Gammal, Arjendu K. Pattanayak

In this paper we introduce a diagnostic for measuring the quantum-classical difference for open quantum systems, which is the normalized size of the quantum terms in the Master equation for Wigner function evolution. For a driven Duffing oscillator, this measure shows remarkably precise scaling over long time-scales with the parameter $ζ_0=\hbar^2/D$. We als

Istvan Szita, Andras Lorincz

In this paper we propose an algorithm for polynomial-time reinforcement learning in factored Markov decision processes (FMDPs). The factored optimistic initial model (FOIM) algorithm, maintains an empirical model of the FMDP in a conventional way, and always follows a greedy policy with respect to its model. The only trick of the algorithm is that the model