April 2008 arXiv papers — page 12

Masao Murakami, Yoshio Hishikawa, Satoshi Miyajima, Yoshiko Okazaki

Laser acceleration promises innovation in particle beam therapy of cancer where an ultra-compact accelerator system for cancer beam therapy can become affordable to a broad range of patients. This is not feasible without the introduction of a technology that is radically different from the conventional accelerator-based approach. The laser acceleration metho

Chandra Nair, Vincent Wang Zizhou

We study the best known general inner bound[MAR '79] and outer bound[N-EG'07] for the capacity region of the two user discrete memory less channel. We prove that a seemingly stronger outer bound is identical to a weaker form of the outer bound that was also presented in [N-EG'07]. We are able to further express the best outer bound in a form that

Carlos O. Lousto, Hiroyuki Nakano

In order to derive the precise gravitational waveforms for extreme mass ratio inspirals (EMRI), we develop a formulation for the second order metric perturbations produced by a point particle moving in the Schwarzschild spacetime. The second order waveforms satisfy a wave equation with an effective source build up from products of the first order perturbatio

Jonathan Landy

We apply the Poisson sum rule to obtain formal expressions for the Fourier coefficients of the potential of a lattice of generalized charge. Each generalized charge is assumed to contribute to the potential a term which depends only on the vector displacement from the charge's location. The coefficients are explicitly calculated for Coulomb and Yukawa-ty

Joern Rossa, Michael Dahlem, Ralf-Juergen Dettmar, Roeland P. van der Marel

(Abridged). We present new high spatial resolution narrowband imaging observations of extraplanar diffuse ionized gas (eDIG) in four late-type, actively star forming edge-on spirals, obtained with ACS on-board HST. Our F658N (H-alpha) observations reveal a multitude of structures on both small and large scales. Whereas all four galaxies have been studied wit

Y. Iwao, Y. -P. Lee, H. -W. Lin, C. -L. Wang

We show that the generating functions of Gromov--Witten invariants with ancestors are invariant under a simple flop, for all genera, after an analytic continuation in the extended Kähler moduli space. This is a sequel to [LLW].

Arun Kumar S P, Diganta Baishya, Amrendra Kumar

Majority of the applications used in defense are voice, video and data oriented and has strict QoS requirements. One of the technologies that enabled this is Asynchronous Transfer Mode (ATM) networking. Traditional ATM networks are wired networks. But Tactical networks are meant to be mobile and this necessitates the use of radio relays for Vehicle-to-Infras

G. Akemann, F. Basile, L. Lellouch

We determine the volume and mass dependence of scalar and pseudoscalar two-point functions in N_f-flavour QCD, in the presence of an isospin chemical potential and at fixed gauge-field topology. We obtain these results at second order in the ε-expansion of Chiral Perturbation Theory and evaluate all relevant zero-mode group integrals analytically. The virtue

Paul M. Saffin, Antonio Padilla, Edmund J. Copeland

We recently investigated the nature of resonant tunnelling in standard scalar Quantum Field Theory, uncovering the conditions required for resonance. It was shown that whereas the homogeneous false vacuum may decay via bubble nucleation, it may not decay in a resonant fashion. The no-go theorem given there is circumvented in this study by considering an init

Aslak Bakke Buan, Osamu Iyama, Idun Reiten, David Smith

We prove that mutation of cluster-tilting objects in triangulated 2-Calabi-Yau categories is closely connected with mutation of quivers with potentials. This gives a close connection between 2-CY-tilted algebras and Jacobian algebras associated with quivers with potentials. We show that cluster-tilted algebras are Jacobian and also that they are determined b

Jin-Ho Cho, Yumi Ko, Soonkeon Nam

Based on the entropy function formalism, we consider the extremal Kerr-(anti-)de Sitter black holes in 4-dimensions. Solving differential equations exactly, which are obtained by extremizing the entropy function, we find agreement of the result with Bekenstein-Hawking entropy. Concerning the higher derivative corrections, we extend the computation to the cas

Cecilia Scannapieco, Patricia B. Tissera, Simon D. M. White, Volker Springel

We use cosmological simulations in order to study the effects of supernova (SN) feedback on the formation of a Milky Way-type galaxy of virial mass ~10^12 M_sun/h. We analyse a set of simulations run with the code described by Scannapieco et al. (2005, 2006), where we have tested our star formation and feedback prescription using isolated galaxy models. Here

Nasser Metwally

We investigate the dynamics of two qubits state through the Bloch channel. It is found that the degradation and sudden-death of the entanglement depend on the channel's parameters and the structure of the input state. Starting from partially entangled states as input state, the output states are more robust compared with those obtained from initial maxim

Nicholas A. Licata, Alexei V. Tkachenko

In recent years there have been a number of proposals to utilize the specificity of DNA based interactions for potential applications in nanoscience. One interesting direction is the self-assembly of micro- and nanoparticle clusters using DNA scaffolds. In this letter we consider a DNA scaffold method to self-assemble clusters of "colored" particles.

R. F. O'Connell

We survey theoretical and experimental/observational results on general-relativistic spin (rotation) effects in binary systems. A detailed discussion is given of the two-body Kepler problem and its first post-Newtonian generalization, including spin effects. Spin effects result from gravitational spin-orbit and spin-spin interactions (analogous to the corres

Ivan Vitev, Ben-Wei Zhang

A theoretical derivation of photon bremsstrahlung, induced by the interactions of an energetic quark in a hot and dense quark-gluon plasma, is given in the framework of the reaction operator approach. For the physically relevant case of hard jet production, followed by few in-medium interactions, we find that the Landau-Pomeranchuk-Migdal suppression of the

S. Desai, E. O. Kahya, R. P. Woodard

We discuss the implications for gravity wave detectors of a class of modified gravity theories which dispense with the need for dark matter. These models, which are known as Dark Matter Emulators, have the property that weak gravitational waves couple to the metric that would follow from general relativity without dark matter whereas ordinary particles coupl

Sung-Sik Lee

We study the stability of the 2+1 dimensional U(1) spin liquid state against proliferation of instantons in the presence of spinon Fermi surface. By mapping the spinon Fermi surface into an infinite set of 1+1 dimensional chiral fermions, it is argued that an instanton has an infinite scaling dimension for any nonzero number of spinon flavors. Therefore, the

P. C. Frisch

The physical properties and kinematics of the partially ionized interstellar material near the Sun are typical of warm diffuse clouds in the solar vicinity. The interstellar magnetic field at the heliosphere and the kinematics of nearby clouds are naturally explained in terms of the S1 superbubble shell. The interstellar radiation field at the Sun appears to

Nimish A. Shah

Extending the earlier results for analytic curve segments, in this article we describe the asymptotic behaviour of evolution of a finite segment of a C^n-smooth curve under the geodesic flow on the unit tangent bundle of a finite volume hyperbolic n-manifold. In particular, we show that if the curve satisfies certain natural geometric conditions, the pushfor

C. B. Jackson

The extremely large hierarchy observed in the fermion mass spectrum remains as one of the most puzzling and unresolved issues in particle physics. In a recent proposal, however, it was demonstrated that by introducing one Higgs doublet (or Private Higgs) per fermion this hierarchy could be made natural by making the Yukawa couplings between each fermion and

Kazumoto Haba, Shinya Matsuzaki, Koichi Yamawaki

We explicitly calculate the $S$ parameter in entire parameter space of the holographic walking/conformal technicolor (W/C TC), based on the deformation of the holographic QCD by varying the anomalous dimension from $γ_m \simeq 0$ through $γ_m \simeq 1$ continuously. The $S$ parameter is given as a positive monotonic function of $ξ$ which is fairly insensitiv

Francois Foucart, Lawrence E. Kidder, Harald P. Pfeiffer, Saul A. Teukolsky

We present a new numerical scheme to solve the initial value problem for black hole-neutron star binaries. This method takes advantage of the flexibility and fast convergence of a multidomain spectral representation of the initial data to construct high-accuracy solutions at a relatively low computational cost. We provide convergence tests of the method for

Fei Lin, Erik S. Sørensen

We report on an effective Hubbard Hamiltonian approach for the study of electronic correlations in C$_{20}$ isomers, cage, bowl and ring, with quantum Monte Carlo and exact diagonalization methods. The tight-binding hopping parameter, $t$, in the effective Hamiltonian is determined by a fit to density functional theory calculations, and the on-site Coulomb i

Amitabha Bagchi, Sohit Bansal

We study the graph constructed on a Poisson point process in $d$ dimensions by connecting each point to the $k$ points nearest to it. This graph a.s. has an infinite cluster if $k > k_c(d)$ where $k_c(d)$, known as the critical value, depends only on the dimension $d$. This paper presents an improved upper bound of 188 on the value of $k_c(2)$. We also show

Seckin Kurkcuoglu

We first review the result that the noncommutative principal chiral model has an infinite tower of conserved currents, and discuss the special case of the noncommutative CP^1 model in some detail. Next, we focus our attention to a submodel of the CP^1 model in the noncommutative spacetime A_θ(R^2+1). By extending a generalized zero curvature representation t

Florent Hivert, Anne Schilling, Nicolas M. Thiéry

The Hecke group algebra $HW_0$ of a finite Coxeter group $W_0$, as introduced by the first and last author, is obtained from $W_0$ by gluing appropriately its 0-Hecke algebra and its group algebra. In this paper, we give an equivalent alternative construction in the case when $W_0$ is the classical Weyl group associated to an affine Weyl group $W$. Namely, w

Igor F. Herbut

Finite flux of the (time-reversal-symmetric) pseudo-magnetic field, which represents the effect of wrinkling of the graphene sheet for example, is shown to be a catalyst for spontaneous breaking of the time-reversal symmetry of Dirac fermions in two dimensions. Possible experimental consequences of this effect for graphene are discussed.

Xinjia Chen

In this paper, we study the classical problem of estimating the proportion of a finite population. First, we consider a fixed sample size method and derive an explicit sample size formula which ensures a mixed criterion of absolute and relative errors. Second, we consider an inverse sampling scheme such that the sampling is continue until the number of units

K. B. Efetov, M. V. Feigel'man, P. B. Wiegmann

We show that the "theory" of "superinsulating" state presented by V.Vinokur et al (Nature vol. 452, p. 613, 2008) and Fistul et al (Phys. Rev. Lett. vol. 100, 086805, 2008) is essentially incorrect due to a sequence of errors in the theoretical analysis of the standard model of Josephson arrays which properties have been carefully studied and

Adam Sierakowski

Let (A,G) be a C*-dynamical system with G discrete. In this paper we investigate the ideal structure of the reduced crossed product C*-algebra and in particular we determine sufficient - and in some cases also necessary - conditions for A to separate the ideals in Ax_rG. When A separates the ideals in Ax_rG, then there is a one-to-one correspondence between

Margaret Hawton

A Lorentz invariant positive definite expression for photon number density is derived as the absolute square of the invariant scalar product of a polarization sensitive position eigenvector and the photon wave function. It is found that this scalar product is independent of the form chosen for the wave function and that the normalized positive frequency vect

NA49 Collaboration

Results on $Λ$, $\barΛ}$, $Ξ^{-}$, and $\barΞ^{+}$ production in central Pb+Pb reactions at 20A, 30A, 40A, 80A, and 158A GeV are presented. The energy dependence of transverse mass spectra, rapidity spectra, and multiplicities is discussed. Comparisons to string hadronic models (UrQMD and HSD) and statistical hadron gas models are shown. While the latter pro

C. M. Carloni Calame, S. Moretti, F. Piccinini, D. A. Ross

We describe the impact of the full one-loop EW terms of O(alpha_s alpha_EM^3) entering the electron-positron into three-jet cross-section from \sqrt{s}=M_Z to TeV scale energies. We include both factorisable and non-factorisable virtual corrections, photon bremsstrahlung but not the real emission of W and Z bosons. Their importance for the measurement of alp

Francesco Dalla Piazza, Bert van Geemen

The finite symplectic group Sp(2g) over the field of two elements has a natural representation on the vector space of Siegel modular forms of given weight for the principal congruence subgroup of level two. In this paper we decompose this representation, for various (small) values of the genus and the level, into irreducible representations. As a consequence

J. M. Velhinho

We present a group of transformations in the space of generalized connections that contains the set of transformations generated by the flux variables of loop quantum gravity. This group is labelled by certain SU(2)-valued functions on the bundle of directions in the spatial manifold. A further generalization is obtained by considering functions that depend

Vernon Barger, Danny Marfatia, Azar Mustafayev

Motivated by the fact that neutrinos are massive, we study the effect of neutrino Yukawa couplings on neutralino dark matter observables within the framework of a supersymmetric seesaw. We find that neutrino couplings significantly affect the neutralino relic density in regions of parameter space where soft SUSY-breaking slepton masses and/or trilinear coupl

Hilary A. Carteret, Kelly John Rose, Stuart A. Kauffman

Random Boolean networks are models of disordered causal systems that can occur in cells and the biosphere. These are open thermodynamic systems exhibiting a flow of energy that is dissipated at a finite rate. Life does work to acquire more energy, then uses the available energy it has gained to perform more work. It is plausible that natural selection has op

Gennadi Henkin

We have obtained the explicit versions and precisions for the Hodge-Riemann decomposition of formes on affine algebraic curve V. The main application consists in the construction of Faddeev-Green function for Laplacian on V. Basing on this [HM](arXiv:0804.3951 and J.Geom.Anal., 2008,18), we extended from the case X in C to the case of bordered Riemann surfac

Gestur Olafsson, Henrik Schlichtkrull

The Fourier coefficients F(t) of a function f on a compact symmetric space U/K are given by integration of f against matrix coefficients of irreducible representations of U. The coefficients depend on a spectral parameter t, which determines the representation, and they can be represented by elements F(t) in a common Hilbert space H. We obtain a theorem of P

Sergei V. Zhukovsky, Dmitry N. Chigrin, Johann Kroha

We investigate the possibility of bistable lasing in microcavity lasers as opposed to bulk lasers. To that end, the dynamic behavior of a microlaser featuring two coupled, interacting modes is analytically investigated within the framework of a semiclassical laser model, suitable for a wide range of cavity shapes and mode geometries. Closed-form coupled mode

G. F. Porto de Mello, W. Lyra, G. R. Keller

The alpha Centauri binary system, owing to its duplicity, proximity and brightness, and its components' likeness to the Sun, is a fundamental calibrating object for the theory of stellar structure and evolution and the determination of stellar atmospheric parameters. This role, however, is hindered by a considerable disagreement in the published analyses of

Jeaman Ahn, Sijong Kwak

Let $X$ be a reduced closed subscheme in $\mathbb P^n$. As a slight generalization of property $\textbf{N}_p$ due to Green-Lazarsfeld, we can say that $X$ satisfies property $\textbf{N}_{2,p}$ scheme-theoretically if there is an ideal $I$ generating the ideal sheaf $\mathcal I_{X/¶^n}$ such that $I$ is generated by quadrics and there are only linear syzygies

Aloysius G. Helminck, Gerald W. Schwarz

Let G be a real form of a complex reductive group. Suppose that we are given involutions σand θof G. Let H=G^σdenote the fixed group of σand let K=G^θdenote the fixed group of θ. We are interested in calculating the double coset space H\backslash G/K. We use moment map and invariant theoretic techniques to calculate the double cosets, especially the ones tha

Damian Rössler

Let $A$ be an abelian variety over ${\bf C}_p$ ($p$ a prime number) and $V\hookrightarrow A$ a closed subvariety. The conjecture of Tate-Voloch predicts that the $p$-adic distance from a torsion point $T\not\in V({\bf C}_p)$ to the variety $V$ is bounded below by a strictly positive constant. This conjecture is proven by Hrushovski and Scanlon, when $A$ has

Hristu Culetu

The kinematical quantities derived from the velocity field of a nongeodesic congruence are studied. We found the shear tensor components are finite in time but diverge at the event horizon of the spacetime located at $ρ= 0$. The surface gravity on the horizon is just the proper acceleration of the uniformly expanding distribution of observers, in spherical R

Neil Dobbs

Ergodic properties of rational maps are studied, generalising the work of F.\ Ledrappier. A new construction allows for simpler proofs of stronger results. Very general conformal measures are considered. Equivalent conditions are given for an ergodic invariant probability measure with positive Lyapunov exponent to be absolutely continuous with respect to a g

Denis S. Goldobin, Elizaveta V. Shklyaeva

We address a problem which is mathematically reminiscent of the one of Anderson localization, although it is related to a strongly dissipative dynamics. Specifically, we study thermal convection in a horizontal porous layer heated from below in the presence of a parametric disorder; physical parameters of the layer are time-independent and randomly inhomogen

Daniel Krasner

For every positive integer $n$ we construct a bigraded homology theory for links, such that the corresponding invariant of the unknot is closely related to the U(n)-equivariant cohomology ring of $\mathbb{CP}^{n-1}$; our construction specializes to the Khovanov-Rozansky $sl_n$-homology. We are motivated by the "universal" rank two Frobenius extension

Byeong-Kweon Oh, Zhi-Wei Sun

In this paper we confirm a conjecture of Sun which states that each positive integer is a sum of a square, an odd square and a triangular number. Given any positive integer m, we show that p=2m+1 is a prime congruent to 3 modulo 4 if and only if T_m=m(m+1)/2 cannot be expressed as a sum of two odd squares and a triangular number, i.e., p^2=x^2+8(y^2+z^2) for

M. C. Werner, J. An, N. W. Evans

A number of recent surveys for gravitational lenses have found examples of double Einstein rings. Here, we investigate analytically the occurrence of multiple Einstein rings. We prove, under very general assumptions, that at most one Einstein ring can arise from a mass distribution in a single plane lensing a single background source. Two or more Einstein ri

E. M. Shin, N. W. Evans

We study the problem of gravitational lensing by binary galaxies, idealized as two isothermal spheres. In a wide binary, each galaxy possesses individual tangential, nearly astroidal, caustics and roundish radial caustics. As the separation of the binary is made smaller, the caustics undergo a sequence of metamorphoses. The first metamorphosis occurs when th

Masato Arai, Nobuchika Okada, Karel Smolek, Vladislav Simak

We study top-antitop pair production and top spin correlations in a model with an electrically neutral massive gauge boson, Z', at the Large Hadron Collider. In addition to the Standard Model processes, the Z' contributes to the top-antitop pair production process in the s-channel. Choosing a kinematical region of top invariant mass around the Z'

Zhaoshun Gao, Lei Wang, Yanpeng Qi, Dongliang Wang

We demonstrate that Fe sheathed LaO0.9F0.1FeAs wires with Ti as a buffer layer were successfully fabricated by the powder-in-tube (PIT) method. Comparing to the common two-step vacuum quartz tube synthesis method, the PIT method is more convenient and safe for synthesizing the novel iron-based layered superconductors. Structural analysis by mean of x-ray dif

Liyan Liu, Zhipeng Liu, Lina Guo

We present a stability analysis of the classical ideal gas in a new theory of nonextensive statistics and use the theory to understand the phenomena of negative specific heat in some self-gravitating systems. The stability analysis is made on the basis of the second variation of Tsallis entropy. It is shown that the system is thermodynamically unstable if th

Sofia Wechsler

A recent article of Colbeck and Renner tackled the problem whether entanglements may be explained by combined models of local and non-local hidden variables. To the difference from previous works they considered models in which each pair of entangled particles behaves in the same way, and the particles in the pair are equivalent, i.e. each of them produces i

A. Jorissen, A. Frankowski

This paper reviews methods which can be used to detect binaries involving low- and intermediate-mass stars, with special emphasis on evolved systems. Besides the traditional methods involving radial-velocity or photometric monitoring, the paper discusses as well less known methods involving astrometry or maser (non-)detection. An extensive list of internet r

Lorenz Schwachhofer, Kristopher Tapp

Given compact Lie groups H\subset G, we study the space of G-invariant metrics on G/H with nonnegative sectional curvature. For an intermediate subgroup K between H and G, we derive conditions under which enlarging the Lie algebra of K maintains nonnegative curvature on G/H. Such an enlarging is possible if (K,H) is a symmetric pair, which yields many new ex

Jie Yang, Zheng-Cai Li, Wei Lu, Wei Yi

Here we report the fabrication and superconductivity of the iron-based arsenic-oxide GdFeAsO1-delta compound with oxygen-deficiency, which has an onset resistivity transition temperature at 53.5 K. This material has a same crystal structure as the newly discovered high-Tc ReFeAsO1-delta family (Re = rare earth metal) and a further reduced crystal lattice, wh

Leonardo Biliotti, Miguel Angel Javaloyes, Paolo Piccione

We consider a family of variational problems on a Hilbert manifold parameterized by an open subset of a Banach manifold, and we discuss the genericity of the nondegeneracy condition for the critical points. Based on an idea of B. White, we prove an abstract genericity result that employs the infinite dimensional Sard--Smale theorem. Applications are given by

Emilio Elizalde, Pedro J. Silva

The ${\bf f}(R)$ gravity field equations are derived as an equation of state of local space-time thermodynamics. Jacobson's arguments are non-trivially extended, by means of a more general definition of local entropy, for which Wald's definition of dynamic black hole entropy is used, as well as the concept of an effective Newton constant for graviton

Crucean Cosmin

The scattering of a charged scalar field on Coulomb potential is studied using solutions of the Klein-Gordon equation which have a definite momentum. One obtains that in contrast with what happens on Minkowski case the modulus of momentum is not conserved in the scattering process on de Sitter space.

Yu. M. Bystritskiy, E. A. Kuraev, M. Sečanský, M. K. Volkov

Radiative decays of pseudoscalar and vector mesons are calculated in the framework of the chiral Nambu-Jona-Lasinio (NJL) model. We use the amplitude for triangle quark loops of anomalous type. In evaluating these loop integrals we use two methods. In the first one, we neglect the dependence of external momenta by reproducing the Wess-Zumino-Witten terms of

Dong Yang, Michal Horodecki, Z. D. Wang

Based on the monogamy of entanglement, we develop the technique of quantum conditioning to build an {\it additive} entanglement measure: the conditional entanglement of mutual information. Its {\it operational} meaning is elaborated to be the minimal net "flow of qubits" in the process of partial state merging. The result and conclusion can also be g

G. E. Volovik

Recent experiments [1],[2] which measured the spectrum of the Goldstone collective mode of coherently precessing state in 3He-B are discussed using the presentation of the coherent spin precession in terms of the Bose-Einstein condensation of magnons. The mass in the spectrum of the Goldstone boson -- phonon in the superfluid magnon liquid -- is induced by t

H. Banerjee, Gautam Bhattacharya

In the anomaly equation for the singlet axial current the chiral limit of the quark mass term does not vanish but comprises contribution from fermion zero modes whose integral exactly cancels the topological charge arising from the Adler-Bell-Jackiw anomaly. This signals chiral symmetry and opens a window for restoring the status of Goldstone boson for the s

Hayato Mikami, Yuji Sato, Tomoaki Matsumoto, Tomoyuki Hanawa

We show three-dimensional magnetohydrodynamical simulations of core collapse supernova in which the progenitor has magnetic fields inclined to the rotation axis. The simulations employed a simple empirical equation of state in which the pressure of degenerate gas is approximated by piecewise polytropes for simplicity. Neither energy loss due to neutrino is t

E. Santini, M. D. Cozma, Amand Faessler, C. Fuchs

The in-medium spectral functions of $ρ$ and $ω$ mesons and the broadening of the nucleon resonances at finite baryon density are calculated self-consistently by combining a resonance dominance model for the vector meson production with an extended vector meson dominance model. The influence of the in-medium modifications of the vector meson properties on the

A. Barrau, A. Gorecki, J. Grain

The Hubble parameter H0 still not very well measured. Although the Hubble Key Project, Chandra and WMAP gave good estimates, the uncertainties remain quite large. In this brief report, we suggest an original and independent method to derive a lower limit on H0 using the absorption of very high energy gamma-rays by the cosmic infrared background. With conserv

M. J. Duff

In 1987 two versions of the brane-scan of D-dimensional super p-branes were put forward. The first pinpointed those (p,D) slots consistent with kappa-symmetric Green-Schwarz type actions; the second generalized the "membrane at the end of the universe" idea to all those superconformal groups describing p-branes on the boundary of AdS_{p+2} x S^{D-p-2

M. Apostol

The quanta of electrical conductance is derived for a one-dimensional electron gas both by making use of the quasi-classical motion of a quantum fluid and by using arguments related to the uncertainty principle. The result is extended to a nanowire of finite cross-section area and to electrons in magnetic field, and the quantization of the electrical conduct

Vladimir Shevelev

We give a simple formula for the exact exponent in the remainder term of the main Gelfond's digit theorem in the binary case.

C Loizides

Presented are the results of a detailed study for a complete simulation of the CMS detectors at the LHC in view of the expected modification of jet fragmentation functions in central Pb+Pb collisions at (s_NN)**0.5=5.5 TeV compared to the vacuum (p+p) case. The study is based on photon-jet events, using the correlation between isolated high-transverse energy

Enrico Onofri

A numerical method is presented which allows to compute the spectrum of the Schroedinger operator for a particle constrained on a two dimensional flat torus under the combined action of a transverse magnetic field and any conservative force. The method employs a fast Fourier transform to accurately represent the momentum variables and takes into account the

Marzio Cassandro, Enza Orlandi, Pierre Picco

We study the one dimensional Ising model with ferromagnetic, long range interaction which decays as |i-j|^{-2+a}, 1/2< a<1, in the presence of an external random filed. we assume that the random field is given by a collection of independent identically distributed random variables, subgaussian with mean zero. We show that for temperature and strength of the

Xiao-Mei Li, Bao-Guo Dong, Yu-Liang Yan, Hai-Liang Ma

We have argued that the azimuthal symmetry and asymmetry components in fourier expansion of particle momentum azimuthal distribution, $v_n$ (n=0, 1, 2, ...), should be calculated as an average of $cos(nϕ)$ first over particles in an event and then over events (event-wise average) rather than &#34;an average over all particles in all events&#34; (particle-wis

Pavel A. Belov, Mario G. Silveirinha, Constantin R. Simovski, Yang Hao

This is a comment on &#34;Guiding, Focusing, and Sensing on the Subwavelength Scale Using Metallic Wire Arrays&#34; by G. Shvets, S. Trendafilov, J. B. Pendry and A. Sarychev published in Phys. Rev. Lett. 99, 053903 (2007), which demonstrates that the endoscope proposed in the letter does not demonstrate satisfactory subwavelength imaging performance.

Huan-Xiong Yang, Hong-Liang Ma

In this paper we present a two-field inflation model, which distinguishes itself with a non-canonical kinetic lagrangian and comes from the large volume approach to the moduli stabilization in flux compactification of type IIB superstring on a Calabi-Yau orientifold of $h^{(1,2)} > h^{(1,1)}\geq 4$. The Kähler moduli are classified as volume modulus, heavy m

Pei-Ming Ho, Yutaka Matsuo

Recently an action based on Lie 3-algebras was proposed to describe M2-branes. We study the case of infinite dimensional Lie 3-algebras based on the Nambu-Poisson structure of three dimensional manifolds. We show that the model contains self-dual 2-form gauge fields in 6 dimensions, and the result may be interpreted as the M5-brane world-volume action.

George Lazarides, Iain N. R. Peddie, Achilleas Vamvasakis

We discuss a new inflationary scenario which is realized within the extended supersymmetric Pati-Salam model which yields an acceptable b-quark mass for universal boundary conditions and mu>0 by modestly violating Yukawa unification and leads to new shifted, new smooth, or standard-smooth hybrid inflation. Inflation takes place along a &#34;semi-shifted&#34;

Pengbo Li

A protocol is proposed to generate atomic entangled states in a cavity QED system. It utilizes Raman transitions or stimulated Raman adiabatic passages between two systems to entangle the ground states of two three-state $Λ$-type atoms trapped in a single mode cavity. It does not need the measurements on cavity field nor atomic detection and can be implement

S. I. Chernyshov, V. S. Ponomarenko, A. V. Voronin

Traditional models of macroeconomic dynamics are fundamentally incorrect. The reason lies in a misunderstanding of peculiarities of the analysis of infinitesimal quantities. However, even those types of solutions that are envisaged by the above-mentioned models are nonrepresentative in the sense of the reflection of realities. It became obvious that the tech

J. -T. Wei, K. -F. Chen

We present a search for the B-> pi e^+ e^- and B-> pi μ^+ μ^- decays, with a data sample of 657 million BBbar pairs collected with the Belle detector at the KEKB $e^+e^-$ collider. Signal events are reconstructed from a charged or a neutral pion candidate and a pair of oppositely charged electrons or muons. No significant signal is observed and we set the up

David Helm, Eric Katz

We find restrictions on the topology of tropical varieties that arise from a certain natural class of varieties. We develop a theory of tropical degenerations that is a nonconstant coefficient analogue of Tevelev's theory of tropical compactifications, and use it to construct normal crossings degenerations of a subvariety X of a torus, under mild hypotheses

Paul Norbury

Kapustin and Witten associate a Hecke modification of a holomorphic bundle over a Riemann surface to a singular monopole on a Riemannian surface times an interval satisfying prescribed boundary conditions. We prove existence and uniqueness of singular monopoles satisfying prescribed boundary conditions for any given Hecke modification data confirming the und

Taras Banakh, Tatsuhiko Yagasaki

We prove that the group D^r(R) of C^r diffeomorphisms of the real line, endowed with the compact-open and Whitney C^r topologies, is bihomeomorphic to the group H(R) of homeomorphisms of the real line endowed with the compact-open and Whitney topologies. This implies that the diffeomorphism group D^r(R) endowed with the Whitney C^r topology is homeomorphic t

L. Ding, C. He, J. K. Dong, T. Wu

The specific heat $C(T)$ of new iron-based high-$T_c$ superconductor SmO$_{1-x}$F$_x$FeAs ($0 \leq x \leq 0.2$) was systematically studied. For undoped $x$ = 0 sample, a specific heat jump was observed at 130 K. This is attributed to the structural or spin-density-wave (SDW) transition, which also manifests on resistivity as a rapid drop. However, this jump

Matthias Beck, Alan Stapledon

For every positive integer $n$, consider the linear operator $\U_{n}$ on polynomials of degree at most $d$ with integer coefficients defined as follows: if we write $\frac{h(t)}{(1 - t)^{d + 1}} = \sum_{m \geq 0} g(m) t^{m}$, for some polynomial $g(m)$ with rational coefficients, then $\frac{\U_{n}h(t)}{(1- t)^{d + 1}} = \sum_{m \geq 0} g(nm) t^{m}$. We show

Thomas Church, Aaron Pixton

The Magnus representation of the Torelli subgroup of the mapping class group of a surface is a homomorphism r: I_{g,1} -> GL_{2g}(Z[H]). Here H is the first homology group of the surface. This representation is not faithful; in particular, Suzuki previously described precisely when the commutator of two Dehn twists about separating curves is in the kernel of

Chun-Lan Ma, Diu Nghiem, Yu-Chang Chen

The transport properties of unsubstituted and amino-substituted butanethiol molecules sandwiched between Au electrodes are investigated by using first-principles approaches. New states are observed around the Fermi levels when -NH2 is substituted for -H in the bridging butanethiol. The amino-substituted states lead to a sharp increase of the current which is

Chiu Man Ho, Yu Nakayama

We give a non-trivially interacting field theory example of scale invariant but non-conformal field theory. The model is based on the exactly solvable Liouville field theory coupled with free scalars deformed by an exactly marginal operator. We show non-vanishing of the trace of the energy-momentum tensor by using the quantum Schwinger-Dyson equation for the

Hui Dong, Daniela Calzetti, Michael Regan, David Thilker

Spitzer IRAC observations of two fields in the XUV-disk of M83 have been recently obtained,3R_{HII} away from the center of the galaxy (R_{HII)=6.6 kpc).GALEX UV images have shown the two fields to host in-situ recent star formation.The IRAC images are used in conjunction with GALEX data and new HI imaging from THINGS to constrain stellar masses and ages of

Nianbei Li, Peter Hanggi, Baowen Li

Merely rocking the temperature in one heat bath can direct a steady heat flux from cold to hot against a non-zero thermal bias in stylized nonlinear lattice junctions that are sandwiched between two heat baths. Likewise, for an average zero-temperature difference between the two contacts a net, ratchet-like heat flux emerges. Computer simulations show that t

André de Gouvêa, James Jenkins

If neutrinos are Majorana fermions, the lepton mixing parameter space consists of six mixing parameters: three mixing angles and three CP-odd phases. A related issue concerns the physical range of the mixing parameters. What values should these take so that all physically distinguishable mixing scenarios are realized? We present a detailed discussion of the

John A. Baldwin

We compute the Heegaard Floer homology of any rational homology 3-sphere with an open book decomposition of the form (T,ϕ), where T is a genus one surface with one boundary component. In addition, we compute the Heegaard Floer homology of any T^2-bundle over S^1 with first Betti number equal to one, and we compare our results with those of Lebow on the embed

David M. Ambrose, Jon Wilkening

We present a spectrally accurate numerical method for finding non-trivial time-periodic solutions of non-linear partial differential equations. The method is based on minimizing a functional (of the initial condition and the period) that is positive unless the solution is periodic, in which case it is zero. We solve an adjoint PDE to compute the gradient of

Wayne Rossman, Nahid Sultana

We prove a theorem about elliptic operators with symmetric potential functions, defined on a function space over a closed loop. The result is similar to a known result for a function space on an interval with Dirichlet boundary conditions. These theorems provide accurate numerical methods for finding the spectra of those operators over either type of functio

Jan Arpe, Elchanan Mossel

We study the problem of learning k-juntas given access to examples drawn from a number of different product distributions. Thus we wish to learn a function f : {-1,1}^n -> {-1,1} that depends on k (unknown) coordinates. While the best known algorithms for the general problem of learning a k-junta require running time of n^k * poly(n,2^k), we show that given

I. Stetcu, C. -P. Liu, J. L. Friar, A. C. Hayes

A permanent electric dipole moment (EDM) of a physical system requires time-reversal (T) and parity (P) violation. Experimental programs are currently pushing the limits on EDMs in atoms, nuclei, and the neutron to regimes of fundamental theoretical interest. Here we calculate the magnitude of the PT-violating EDM of 3He and the expected sensitivity of such

Garry W. Angus

We take the line of sight velocity dispersions as functions of radius for 8 Milky Way dwarf spheroidal galaxies and use Jeans analysis to calculate the mass-to-light ratios (M/L) in Modified Newtonian Dynamics (MOND). Using the latest structural parameters, distances and variable velocity anisotropy, we find 6/8 dwarfs have sensible M/L using only the stella