Research archive

arXiv papers from November 2006

The most recent 100 records published that month. Open any paper for its original abstract, citation metadata, related research, and reading tools.

  1. M. Cenkci, Y. Simsek, V. Kurt

    This object of this paper to give several properties and applications of multiple p-adic q-L-function of two variables.

  2. Martin H. Weissman

    The space of elliptic modular forms of fixed weight and level can be identfied with a space of intertwining operators, from a holomorphic discrete series representation of SL2(R) to a space of automorphic forms. Moreover, multiplying elliptic modular forms corresponds to a branching problem involving tensor products of holomorphic discrete series representat

  3. T. Kunimatsu, T. Sato, K. Izumina, A. Matsubara

    We report on orientation of the order parameter in the 3He-A and 3He-B phases caused by aerogel anisotropy. In 3He-A we have observed relatively homogeneous NMR line with an anomalously large negative frequency shift. We can attribute this effect to an orientation of orbital momentum along the axis of density anisotropy. The similar orientation effect we hav

  4. P. Coleman

    An introduction to the physics of heavy fermion compounds is presented, attempting to highlight the conceptual developments and emphasize the mysteries and open questions that persist in this active field of research.

  5. Stefan Grosskinsky, Gunter M. Schutz, Richard D. Willmann

    We study spontaneous symmetry breaking in a one-dimensional driven two-species stochastic cellular automaton with parallel sublattice update and open boundaries. The dynamics are symmetric with respect to interchange of particles. Starting from an empty initial lattice, the system enters a symmetry broken state after some time T_1 through an amplification lo

  6. Richard A. Shaw, WArren A. Reid, Quentin A. Parker

    We present Hubble Space Telescope (HST) images of new planetary nebulae (PNe) that were discovered in the Reid-Parker AAO/UKST H-alpha survey of the Large Magellanic Cloud. These serendipitous observations from various HST programs yield independent confirmations of 6 PNe; one other detected nebula may also be a PN, and one appears to be a region of diffuse

  7. Jun Goryo, Mahito Kohmoto, Yong-Shi Wu

    In this paper we propose the quantized spin Hall effect (SHE) in the vortex state of a rotating p-wave paired Fermi system in an inhomogeneous magnetic field and in a weak periodic potential. It is the three dimensional extension of the spin Hall effect for a 3He-A superfluid film studied in Ref. [1]. It may also be considered as a generalization of the 3D q

  8. Jie Zhang, Robert P. Behringer, Alexander Oron

    Marangoni instabilities in binary mixtures are different from those in pure liquids. In contrast to a large amount of experimental work on Marangoni convection in pure liquids, such experiments in binary mixtures are not available in the literature, to our knowledge. Using binary mixtures of sodium chloride/water, we have systematically investigated the patt

  9. Ben W. Reichardt

    A quantum computer -- i.e., a computer capable of manipulating data in quantum superposition -- would find applications including factoring, quantum simulation and tests of basic quantum theory. Since quantum superpositions are fragile, the major hurdle in building such a computer is overcoming noise. Developed over the last couple of years, new schemes for

  10. Alex E. Bernardini, Marcelo M. Guzzo, Fernando R. Torres

    We report about an analytic study involving the {\em intermediate} wave packet formalism for quantifying the physically relevant information which appear in the neutrino two-flavor conversion formula and help us to obtain more precise limits and ranges for neutrino flavor oscillation. By following the sequence of analytic approximations where we assume a str

  11. Reba M. Bandyopadhyay, Andrew J. Gosling, Katherine M. Blundell, Philipp Podsiadlowski

    We present results of a multi-wavelength program to study the faint discrete X-ray source population discovered by Chandra in the Galactic Centre (GC). From IR imaging obtained with the VLT we identify candidate K-band counterparts to 75% of the X-ray sources in our sample. By combining follow-up VLT K-band spectroscopy of a subset of these candidate counter

  12. Willemien Visser

    An observational study was conducted on a professional designer working on a design project in aerospace industry. The protocol data were analyzed in order to gain insight into the actions the designer used for the development of a solution to the corresponding problem. Different processes are described: from the "simple" evocation of a solution existing in

  13. Patrick D'Astous, Pierre Robillard, Françoise Détienne, Willemien Visser

    Peer review meetings (PRMs) are formal meetings during which peers systematically analyze artifacts to improve their quality and report on non-conformities. This paper presents an approach based on protocol analysis for quantifying the influence of participant roles during PRMs. Three views are used to characterize the seven defined participant roles. The pr

  14. Jean-Marie Burkhardt, Françoise Détienne, Susan Wiedenbeck

    The goal of our study is to evaluate the effect on program comprehension of three factors that have not previously been studied in a single experiment. These factors are programmer expertise (expert vs. novice), programming task (documentation vs. reuse), and the development of understanding over time (phase 1 vs. phase 2). This study is carried out in the c

  15. Willemien Visser, Brigitte Trousse

    This text analyses the papers accepted for the workshop "Reuse of designs: an interdisciplinary cognitive approach". Several dimensions and questions considered as important (by the authors and/or by us) are addressed: What about the "interdisciplinary cognitive" character of the approaches adopted by the authors? Is design indeed a domain where the use of C

  16. Olivier Bernardi

    For any graph G with n edges, the spanning subgraphs and the orientations of G are both counted by the evaluation T_G(2,2)=2^n of its Tutte polynomial. We define a bijection $\Phi$ between spanning subgraphs and orientations and explore its enumerative consequences regarding the Tutte polynomial. The bijection $\Phi$ is closely related to a recent characteri

  17. Cyril Petitjean, Diego V. Bevilaqua, Eric J. Heller, Philippe Jacquod

    Motivated by neutron scattering experiments, we investigate the decay of the fidelity with which a wave packet is reconstructed by a perfect time-reversal operation performed after a phase space displacement. In the semiclassical limit, we show that the decay rate is generically given by the Lyapunov exponent of the classical dynamics. For small displacement

  18. D. J. Bohm, P. G. Davies, B. J. Hiley

    We discuss the relation between the q-number approach to quantum mechanics suggested by Dirac and the notion of "pregeometry" introduced by Wheeler. By associating the q-numbers with the elements of an algebra and regarding the primitive idempotents as "generalized points" we suggest an approach that may make it possible to dispense with an a priori given sp

  19. Brian A. Powell, William H. Kinney

    We consider the effects on the primordial power spectrum of a period of radiation-dominated expansion prior to the inflationary era. If inflation lasts a total of only 60 e-folds or so, the boundary condition for quantum modes cannot be taken in the short-wavelength limit as in the standard perturbation calculation. Instead, the boundary condition is set by

  20. Michael Beeson

    Let C be a real-analytic Jordan curve in $R^3$. Then C cannot bound infinitely many disk-type minimal surfaces which provide relative minima of area.

  21. Pavle V. M. Blagojevic, Aleksandra S. Dimitrijevic Blagojevic, John McCleary

    In combinatorial problems it is sometimes possible to define a $G$-equivariant mapping from a space $X$ of configurations of a system to a Euclidean space $\mathbb{R}^m$ for which a coincidence of the image of this mapping with an arrangement $\mathcal{A}$ of linear subspaces insures a desired set of linear conditions on a configuration. Borsuk-Ulam type the

  22. Richard J. Stancliffe, C. Simon Jeffery

    We investigate the uncertainty in surface abundances and yields of asymptotic giant branch (AGB) stars. We apply three different mass loss laws to a 1.5 solar mass star of metallicity Z=0.008 at the beginning of the thermally pulsing asymptotic giant branch (TP-AGB) phase. Efficient third dredge-up is found even at very low envelope mass, contrary to previou

  23. Gonzalo J. Olmo

    We study modified theories of gravity of the f(R) type in Palatini formalism. For a generic f(R) lagrangian, we show that the metric can be solved as the product of a scalar function times a rank-two tensor (or auxiliary metric). The scalar function is sensitive to the local energy-momentum density. The auxiliary metric satisfies a set of equations very simi

  24. F. Kalkum, G. Gay, O. Alloschery, J. Weiner

    We apply the technique of far-field interferometry to measure the properties of surface waves generated by two-dimensional (2D) single subwavelength slit-groove structures on gold films. The effective surface index of refraction measured for the surface wave propagating over a distance of more than 12 microns is determined to be 1.016 with a measurement unce

  25. Mark Hannam, Sascha Husa, Bernd Bruegmann, Jose A. Gonzalez

    It is well-known that Bowen-York initial data contain spurious radiation. Although this ``junk'' radiation has been seen to be small for non-spinning black-hole binaries in circular orbit, its magnitude increases when the black holes are given spin. It is possible to reduce the spurious radiation by applying the puncture approach to multiple Kerr black holes

  26. D. A. Sokolov, M. C. Aronson, C. Henderson, J. W. Kampf

    We have succeeded in synthesizing of single crystals of a new intermetallic compound, Ce$_{3}$Rh$_{4}$Pb$_{13}$. Magnetic susceptibility measurements indicate that the Ce moments are highly localized, despite the metallic character of the electrical resistivity. Heat capacity measurements reveal that the cubic crystal electric field lifts the six-fold degene

  27. B. D. Lehmer, W. N. Brandt, D. M. Alexander, E. F. Bell

    We investigate the evolution over the last 6.3 Gyr of cosmic time (i.e., since z ~ 0.7) of the average X-ray properties of early-type galaxies within the Extended Chandra Deep Field-South (E-CDF-S). Our early-type galaxy sample includes 539 objects with red-sequence colors and Sersic indices larger than n = 2.5, which were selected jointly from the COMBO-17

  28. Antonio Enea Romano

    We show that positive averaged acceleration obtained in LTB models through spatial averaging can require integration over a region beyond the event horizon of the central observer. We provide an example of a LTB model with positive averaged acceleration in which the luminosity distance does not contain information about the entire spatially averaged region,

  29. Yucel Yildirim, Gonzalo Alvarez, Adriana Moreo, Elbio Dagotto

    The properties of Mn-doped GaAs are studied at several doping levels and hole compensations, using a real-space Hamiltonian on an fcc lattice that reproduces the valence bands of undoped GaAs. Large-scale Monte Carlo (MC) simulations on a Cray XT3 supercomputer, using up to a thousand nodes, were needed to make this effort possible. Our analysis considers bo

  30. Rubens Viana Ramos

    In this work, are used Chaitin number Omega and the fact that the general decomposition of an N-way disentangled state is an irreducible sentence whose number of coefficients grows in a non-polynomial way with N, to construct a problem that can never be solved in P.

  31. Ji Jianghui, Liu Lin, Li Guangyu

    We investigate the secular resonances for massless small bodies and Earth-like planets in several planetary systems. We further compare the results with those of Solar System. For example, in the GJ 876 planetary system, we show that the secular resonances $\nu_1$ and $\nu_2$ (respectively, resulting from the inner and outer giant planets) can excite the ecc

  32. Doron Bergman, Jason Alicea, Emanuel Gull, Simon Trebst

    Frustration refers to competition between different interactions that cannot be simultaneously satisfied, a familiar feature in many magnetic solids. Strong frustration results in highly degenerate ground states, and a large suppression of ordering by fluctuations. Key challenges in frustrated magnetism are characterizing the fluctuating spin-liquid regime a

  33. Roman V. Buniy, Thomas W. Kephart

    It is well known that for a field theory with the Chern-Simons action, expectation values of Wilson line operators are topological invariants. The standard result is expressed in terms of the Gaussian linkings of closed curves defining the operators. We show how judicious choice of Wilson lines leads to higher order topological linkings.

  34. M. Revnivtsev, A. Vikhlinin, S. Sazonov

    We use Chandra deep observations of the Galactic Center (GC) region to improve the constraints on the unresolved fraction of the Galactic X-ray background (also known as the Galactic ridge X-ray emission). We emphasize the importance of correcting the measured source counts at low fluxes for bias associated with Poisson noise. We find that at distances of 2'

  35. J. -P. Blaizot, E. Iancu, U. Kraemmer, A. Rebhan

    We apply the previously proposed scheme of approximately self-consistent hard-thermal-loop resummations in the entropy of high-temperature QCD to N=4 supersymmetric Yang-Mills (SYM) theories and compare with a (uniquely determined) R[4,4] Pad\'e approximant that interpolates accurately between the known perturbative result and the next-to-leading order stron

  36. I. Agullo, J. Navarro-Salas, Gonzalo J. Olmo, Leonard Parker

    The Hawking effect can be rederived in terms of two-point functions and in such a way that it makes it possible to estimate, within the conventional semiclassical theory, the contribution of ultrashort distances to the Planckian spectrum. For Schwarzschild black holes of three solar masses the analysis shows that Hawking radiation is very robust up to freque

  37. A. Paramekanti, E. Zhao

    Angle resolved photoemission experiments by Kanigel, et al (cond-mat/0605499) [Nature Physics 2, 447 (2006)] have made a remarkable observation that low energy electronic excitations in the normal state of underdoped cuprate superconductors exist on open ``Fermi arcs'' instead of a closed Fermi surface. These arcs shrink upon cooling, with the arc length app

  38. Levent Akant, Govind S. Krishnaswami

    This work concerns single-trace correlations of Euclidean multi-matrix models. In the large-N limit we show that Schwinger-Dyson equations imply loop equations and non-anomalous Ward identities. Loop equations are associated to generic infinitesimal changes of matrix variables (vector fields). Ward identities correspond to vector fields preserving measure an

  39. Ping Chu, D. L. Mills

    We develop the theory of Brillouin light scattering (BLS) from spin wave modes in ferromagnetic nanospheres, within a framework that incorporates the spatial variation of the optical fields within the sphere. Our recent theory of exchange dipole spin wave modes of the sphere provides us with eigenvectors. When properly normalized, these eigenvectors allow ca

  40. Girma Hailu, S. -H. Henry Tye

    We study corrections to the anomalous mass dimension and their effects in the Seiberg duality cascade in the Klebanov-Strassler throat, where $\mathcal{N}=1$ supersymmetric $SU(N+M)\times SU(N)$ gauge theory with bifundamental chiral superfields and a quartic tree level superpotential in four dimensions is dual to type IIB string theory on $AdS_5 \times T^{1

  41. Thomas P. Sotiriou

    The way one chooses to couple gravity to matter is an essential characteristic of any gravitational theory. In theories where the gravitational field is allowed to have more degrees of freedom than those of General Relativity (e.g. scalar-tensor theory, f(R) gravity) this issue often becomes even more important. We concentrate here on f(R) gravity treated wi

  42. Constantinos Simserides

    Under an in-plane magnetic field, the density of states of quasi two-dimensional carriers deviates from the occasionally stereotypic step-like form both quantitatively and qualitatively. For the first time, we study how this affects the spin-subband populations and the spin-polarization as functions of the temperature, T, and the in-plane magnetic field, B,

  43. Michael T. Busha, August E. Evrard, Fred C. Adams

    We explore the effects of small scale structure on the formation and equilibrium of dark matter halos in a universe dominated by vacuum energy. We present the results of a suite of four N-body simulations, two with a LCDM initial power spectrum and two with WDM-like spectra that suppress the early formation of small structures. All simulations are run into t

  44. Lei Shi, Xianfeng Chen

    Based on the basic theory of the microfiber loop resonator, we exploit the application of microfiber loop resonators in biochemical sensing. We set up a reliable theoretical model and optimize the structural parameters of microfiber loop resonators including the radius of the microrfiber, the radius of the loop and the length of the coupling region for highe

  45. Florentin Smarandache

    A great number of articles widen a known scientific result $P(a)$ (such as: a theorem, an inequality, or a math/physics/chemical etc. proposition or formula) by a simple recurrence procedure and using, in the proof, the proposition $P(a)$ itself. We present, as examples, the generalizations of H\"older's inequality, of Minkovski's inequality, of Tchebychev's

  46. Jian Zhai

    An upper bound of blow up rate for the Navier-Stokes equations with small data in L^2(R^3) is obtained.

  47. Michael C. Abbott, David A. Lowe

    A quantum deformation of three-dimensional de Sitter space was proposed in hep-th/0407188. We use this to calculate the entropy of Kerr-de Sitter space, using a canonical ensemble, and find agreement with the semiclassical result.

  48. Eugene V. Sukhorukov, Andrew N. Jordan

    We generalize the stochastic path integral formalism by considering Hamiltonian dynamics in the presence of general Markovian noise. Kramers' solution of the activation rate for escape over a barrier is generalized for non-Gaussian driving noise in both the overdamped and underdamped limit. We apply our general results to a Josephson junction detector measur

  49. Jian Zhai

    We consider the interior regularity of Leray-Hopf solutions to Navier-Stokes equations on critical case L^2_w(0,T;L^\infty(R^3)). Particularly, an open problem proposed in [KK] was solved.

  50. Emmanuel Candes, Justin Romberg

    We consider the problem of reconstructing a sparse signal $x^0\in\R^n$ from a limited number of linear measurements. Given $m$ randomly selected samples of $U x^0$, where $U$ is an orthonormal matrix, we show that $\ell_1$ minimization recovers $x^0$ exactly when the number of measurements exceeds \[ m\geq \mathrm{Const}\cdot\mu^2(U)\cdot S\cdot\log n, \] wh

  51. Verena Werth, Michael Buballa, Micaela Oertel

    We study pseudoscalar meson excitations in the color-flavor locked phase within a Nambu-Jona-Lasinio-type model by calculating diquark loops.

  52. Ralf Schiffler

    We consider the Ptolemy cluster algebras, which are cluster algebras of finite type $A$ (with non-trivial coefficients) that have been described by Fomin and Zelevinsky using triangulations of a regular polygon. Given any seed $\zS$ in a Ptolemy cluster algebra, we present a formula for the expansion of an arbitrary cluster variable in terms of the cluster v

  53. Ivan Horozov

    We define iteration over a two dimensional manifold as analog of iteration over a path defined by Chen. We give several applications. Some of them include constructions of non-abelian modular symbol for $SL(3,\Z)$ and for $SL_{2/K}$, where $K$ is a real quadratic field. We construct the latter as generating series of iterated integrals over a two-dimensional

  54. Ilya Fushman, Edo Waks, Dirk Englund, Nick Stoltz

    We demonstrate fast (up to 20 GHz), low power (5 $\mu W$) modulation of photonic crystal (PC) cavities in GaAs containing InAs quantum dots. Rapid modulation through blue-shifting of the cavity resonance is achieved via free carrier injection by an above-band picosecond laser pulse. Slow tuning by several linewidths due to laser-induced heating is also demon

  55. Gabriel B. Brammer, Pieter G. van Dokkum

    We use the deep NIR imaging of the FIRES survey to investigate trends with redshift of the properties of galaxies selected to have strong Balmer/4000A breaks at 2<z<4.5. Analagous to the J-K>1.3 (AB) color criterion designed to select red galaxies at z>2, we propose two color criteria, J-H>0.9 and H-K>0.9, to select red galaxies in two redshift bins at 2<z<3

  56. Howard Barnum, Jonathan Barrett, Matthew Leifer, Alexander Wilce

    We prove generic versions of the no-cloning and no-broadcasting theorems, applicable to essentially {\em any} non-classical finite-dimensional probabilistic model that satisfies a no-signaling criterion. This includes quantum theory as well as models supporting ``super-quantum'' correlations that violate the Bell inequalities to a larger extent than quantum

  57. Claude M. Dion, Peder Sjolund, Stefan J. H. Petra, Svante Jonsell

    We study a Brownian motor, based on cold atoms in optical lattices, where atomic motion can be induced in a controlled manner in an arbitrary direction, by rectification of isotropic random fluctuations. In contrast with ratchet mechanisms, our Brownian motor operates in a potential that is spatially and temporally symmetric, in apparent contradiction to the

  58. Brian E. Wood, Vladislav V. Izmodenov, Jeffrey L. Linsky, Yury G. Malama

    We assess what information HST observations of stellar Ly-alpha lines can provide on the heliosheath, the region of the heliosphere between the termination shock and heliopause. To search for evidence of heliosheath absorption, we conduct a systematic inspection of stellar Ly-alpha lines reconstructed after correcting for ISM absorption (and heliospheric/ast

  59. Kanokkuan Chaicherdsakul

    This paper extends the calculation of quantum corrections to the cosmological correlation $<\zeta\zeta>$, which has been done by Weinberg for a loop of minimally coupled scalars, to other types of matter loops and a general and realistic potential. It is shown here that departures from scale invariance are never large even when Dirac, vector, and conformal s

  60. Jeff Cheeger, Bruce Kleiner

    This is one of a series of papers examining the interplay between differentiation theory for Lipschitz maps, X-->V, and bi-Lipschitz nonembeddability, where X is a metric measure space and V is a Banach space. Here, we consider the case V=L^1 where differentiability fails. We establish another kind of differentiability for certain X, including R^n and H, the

  61. A. I. Machavariani

    Starting with the conformal transformations in the momentum space, the nonlinear $\sigma$-model and the standard model with the spontaneous broken $SU(2)\times U(1)$ symmetry are reproduced. The corresponding chiral Lagrangians are given in the five dimensional form because for the conformal transformations of the four-momentum $q_{\mu}$ ($q'_{\mu}=q_{\mu}+h

  62. M. Salvatori

    We analyze a SU(N) gauge theory on $\mathcal{M}_4 \times T^2$. We find and catalogue all possible degenerate zero-energy stable configurations in the case of trivial or non-trivial 't Hooft non abelian flux. We describe the residual symmetries of each vacua and the 4-dimensional effective spectrum in terms of continous and discrete parameters, respectively.

  63. Jochen Bruening, Vladimir Geyler, Konstantin Pankrashkin

    We give a self-contained presentation of the theory of self-adjoint extensions using the technique of boundary triples. A description of the spectra of self-adjoint extensions in terms of the corresponding Krein maps (Weyl functions) is given. Applications include quantum graphs, point interactions, hybrid spaces, singular perturbations.

  64. S. Gandolfi, F. Pederiva, S. Fantoni, K. E. Schmidt

    We present an accurate numerical study of the equation of state of nuclear matter based on realistic nucleon--nucleon interactions by means of Auxiliary Field Diffusion Monte Carlo (AFDMC) calculations. The AFDMC method samples the spin and isospin degrees of freedom allowing for quantum simulations of large nucleonic systems and represents an important step

  65. E. G. Maksimov, S. V. Ebert, M. V. Magnitskaya, A. E. Karakozov

    Ab initio linear-response calculations are reported of the phonon spectra and the electron-phonon interaction for several transition metal carbides and nitrides in a NaCl-type structure. For NbC, the kinetic, optical, and superconducting properties are calculated in detail at various pressures and the normal-pressure results are found to well agree with the

  66. Camillo Imbimbo

    We present a level (10,30) numerical computation of the spectrum of quadratic fluctuations of Open String Field Theory around the tachyonic vacuum, both in the scalar and in the vector sector. Our results are consistent with Sen's conjecture about gauge-triviality of the small excitations. The computation is sufficiently accurate to provide robust evidence f

  67. Stefan Heinrich

    We use entropy numbers in combination with the polynomial method to derive a new general lower bound for the n-th minimal error in the quantum setting of information-based complexity. As an application, we improve some lower bounds on quantum approximation of embeddings between finite dimensional L_p spaces and of Sobolev embeddings.

  68. E. V. Tkalya

    We propose a model for description of the process of Nuclear Excitation by Electron Transition (NEET) near the $K$-shell ionization threshold of an atom. We explain the experimental results for the $^{197}$Au cross section excitation $\sigma_{N^*}$ obtained by S.Kishimoto et al. Phys. Rev. C {\bf 74}, 031301(R) (2006) using synchrotron radiation near the Au

  69. Fabio L. Braghin

    Some consequences of a classical vector field (chromo-electromagnetic field) coupled to quarks, which undergo to superfluid and/or superconductive states with diquark / diantiquark condensation, are investigated. For this, one scalar field exchange is considered in the lines investigated by Pisarski and Rischke \cite{PISARSKI-RISCHKE} in the mean field appro

  70. Sacha Davidson, Gino Isidori, Alessandro Strumia

    We consider models where one Majorana neutrino is massless at tree level (like the see saw with two right-handed neutrinos), and compute the contribution to its mass m generated by two-loop quantum corrections. The result is m \sim 10^{-13}eV in the SM and m \sim 10^{-10} eV (tanBeta/10)^4 in the MSSM, compatible with the restricted range suggested by Afflec

  71. Robin Hartshorne, Juan Migliore, Uwe Nagel

    We study the concept of liaison addition for codimension two subschemes of an arithmetically Gorenstein projective scheme. We show how it relates to liaison and biliaison classes of subschemes and use it to investigate the structure of Gorenstein liaison equivalence classes, extending the known theory for complete intersection liaison of codimension two subs

  72. Alessandro Mossa, Cecilia Clementi

    The recently discovered supersymmetric generalizations of Langevin dynamics and Kramers equation can be utilized for the exploration of free energy landscapes of systems whose large time-scale separation hampers the usefulness of standard molecular dynamics techniques. The first realistic application is here presented. The system chosen is a minimalist model

  73. Reijo Keskitalo, Hannu Kurki-Suonio, Vesa Muhonen, Jussi Valiviita

    The improved data on the cosmic microwave background (CMB) anisotropy allow a better determination of the adiabaticity of the primordial perturbation. Interestingly, we find that recent CMB data seem to favor a contribution of a primordial isocurvature mode where the entropy perturbation is positively correlated with the primordial curvature perturbation and

  74. T. W. B. Muxlow, R. J. Beswick, A. M. S. Richards, H. Thrall

    Star-formation and the Starburst phenomenon are presented with respect to a number of nearby star-forming galaxies where our understanding of the process can be calibrated. Methods of estimating star-formation rates are discussed together with the role played in the investigation of the process by multi-wavelength studies of a few selected starburst galaxies

  75. Francesco Giacosa

    A chiral invariant Lagrangian describing the tetraquark-quarkonia interaction is considered at the leading and subleading order in the large-$N_{c}$ expansion. Spontaneous chiral symmetry breaking generates mixing of scalar tetraquark and quarkonia states and non-vanishing tetraquark condensates. In particular, the mixing strength is related to the decay str

  76. Hari K. Kunduri, James Lucietti, Harvey S. Reall

    We determine the most general near-horizon geometry of a supersymmetric, asymptotically anti-de Sitter, black hole solution of five-dimensional minimal gauged supergravity that admits two rotational symmetries. The near-horizon geometry is that of the supersymmetric, topologically spherical, black hole solution of Chong et al. This proves that regular supers

  77. Douglas C. Heggie, Piet Hut, Shin Mineshige, Jun Makino

    (Simplified) We present a theoretical framework which establishes how the core radius of a star cluster varies with the mass of an assumed central black hole. Our result is that the ratio of core to half-mass radius varies as the 3/4 power of the ratio of the black hole to cluster mass, when the system is well relaxed. The theory compares favourably with a n

  78. Georges Maltsiniotis

    The aim of this paper is to present a very simple original, purely formal, proof of Quillen's adjunction theorem for derived functors, and of some more recent variations and generalizations of this theorem. This is obtained by proving an abstract adjunction theorem for "absolute" derived functors. In contrast with all known proofs, the explicit construction

  79. Olaf Hohm

    We analyze the symmetries that are realized on the massive Kaluza-Klein modes in generic D-dimensional backgrounds with three non-compact directions. For this we construct the unbroken phase given by the decompactification limit, in which the higher Kaluza-Klein modes are massless. The latter admits an infinite-dimensional extension of the three-dimensional

  80. Amihay Hanany, Christian Romelsberger

    This note is presenting the generating functions which count the BPS operators in the chiral ring of a N=2 quiver gauge theory that lives on N D3 branes probing an ALE singularity. The difficulty in this computation arises from the fact that this quiver gauge theory has a moduli space of vacua that splits into many branches -- the Higgs, the Coulomb and mixe

  81. Michele Della Morte, Patrick Fritzsch, Jochen Heitger

    We perform the non-perturbative renormalization of matrix elements of the static-light axial current by a computation of its scale dependence in lattice QCD with two flavours of massless O(a) improved Wilson quarks. The regularization independent factor that relates any running renormalized matrix element of the axial current in the static effective theory t

  82. Luciana Bianchi, Lino Rodriguez-Merino, Maurice Viton, Michel Laget

    We use the Galaxy Evolution Explorer (GALEX) Medium and All-Sky-Imaging Survey (MIS & AIS) data from the first public data release (GR1), matched to the Sloan Digital Sky Survey (SDSS) DR3 catalog, to perform source classification. The GALEX surveys provide photometry in far- and near-UV bands and the SDSS in five optical bands (u,g,r,i,z). The GR1/DR3 overl

  83. L. A. Barreiro, R. Medina

    In this work we report on recent progress in the calculation of open superstring scattering amplitudes, at tree level, with more than four external massless states. We also report on the corresponding terms in the low energy effective lagrangian.

  84. Martin Lemoine, Jerome Martin

    We build a realistic model of curvaton cosmology, in which the energy content is described by radiation, WIMP dark matter and a curvaton component. We calculate the curvature and isocurvature perturbations, allowing for arbitrary initial density perturbations in all fluids, following all species and their perturbations from the onset of dark matter freeze-ou

  85. Joshua Pepper, Richard Pogge, D. L. DePoy, J. L. Marshall

    The Kilodegree Extremely Little Telescope (KELT) project is a small-aperture transit survey of bright stars. The project has completed commissioning runs searching for transits in the Hyades and Praesepe, and is well into a multi-year survey of a large portion of the Northern Hemisphere. Here we describe the setup of the telescope and discuss the early data.

  86. Luca Grisa

    We study intersecting D-brane models, that describe at low energies a two dimensional chiral fermion theory localized at the intersection. The fermions are coupled to gauge fields in the bulk. The resulting low energy theory is equivalent to the Gross-Neveu model with dynamical chiral symmetry breaking. No Nambu-Goldstone boson associated with spontaneously

  87. H. B. Thacker

    Monte Carlo studies of pure glue SU(3) gauge theory using the overlap-based topological charge operator have revealed a laminar structure in the QCD vacuum consisting of extended, thin, coherent, locally 3-dimensional sheets of topological charge embedded in 4D space, with opposite sign sheets interleaved. In this talk I discuss the interpretation of these M

  88. Helena Albuquerque, Florin Panaite

    We analyze some relations between quasi-Hopf smash products and certain twisted tensor products of quasialgebras. Along the way we obtain also some results of independent interest, such as a duality theorem for finite dimensional quasi-Hopf algebras and a universal property for generalized diagonal crossed products.

  89. Weiqiang Wang

    We introduce the spin Hecke algebra, which is a q-deformation of the spin symmetric group algebra, and its affine generalization. We establish an algebra isomorphism which relates our spin (affine) Hecke algebras to the (affine) Hecke-Clifford algebras of Olshanski and Jones-Nazarov. Relation between the spin (affine) Hecke algebra and a nonstandard presenta

  90. Bertrand Eynard

    This article is a short review on the relationship between convergent matrix integrals, formal matrix integrals, and combinatorics of maps. We briefly summarize results developed over the last 30 years, as well as more recent discoveries. We recall that formal matrix integrals are identical to combinatorial generating functions for maps, and that formal matr

  91. Jean-François Delmas, Benjamin Jourdain

    The Metropolis Hastings algorithm and its multi-proposal extensions are aimed at the computation of the expectation $<\pi,f>$ of a function $f$ under a probability measure $\pi$ difficult to simulate. They consist in constructing by an appropriate acceptation/rejection procedure a Markov chain $(X_k,k\geq 0)$ with transition matrix $P$ such that $\pi$ is rev

  92. Jean-Paul Auffray

    Samuel Preston's 1875 postulates concerning the nature ether are reviewed.

  93. H. G. Roberts, S. Crampin, S. J. Bending

    We demonstrate the presence of an important anisotropic magnetoresistance contribution to the domain wall resistance recently measured in thin-film (Ga,Mn)As with in-plane magnetic anisotropy. Analytic results for simple domain wall orientations supplemented by numerical results for more general cases show this previously omitted contribution can largely exp

  94. Laura Andrianopoli, Riccardo D'Auria, Sergio Ferrara, Mario Trigiante

    We present the main features of the physics of extremal black holes embedded in supersymmetric theories of gravitation, with a detailed analysis of the attractor mechanism for BPS and non-BPS black-hole solutions in four dimensions.

  95. Eric D. Chisolm

    I briefly review the ''decohering histories'' or ''consistent histories'' formulation of quantum theory, due to Griffiths, Omnes, and Gell-Mann and Hartle (and the subject of my graduate work with George Sudarshan). I also sift through the many meanings that have been attached to decohering histories, with an emphasis on the most basic one: Decoherence of ap

  96. A. D. Rata, H. Braak, D. E. Buergler, C. M. Schneider

    Magnetic tunnel junctions with the layer sequence Co$_2$Cr$_{0.6}$Fe$_{0.4}$Al/MgO/CoFe were fabricated by magnetron sputtering at room temperature (RT). The samples exhibit a large inverse tunneling magnetoresistance (TMR) effect of up to -66% at RT. The largest value of -84% at 20 K reflects a rather weak influence of temperature. The dependence on the vol

  97. D. Ivaneyko, B. Berche, Yu. Holovatch, Ja. Ilnytskyi

    In this Monte Carlo study we concentrated on the influence of non-magnetic impurities arranged as the lines with random orientation on paramagnetic-to-ferromagnetic phase transition in the 3D Ising model. Special emphasize is given to the long-distance decay of the impurity-impurity pair correlation function. It is shown that for the lattice sizes considered

  98. Howard Baer, Azar Mustafayev, Eun-Kyung Park, Xerxes Tata

    In the post-LEP2 era, and in light of recent measurements of the cosmic abundance of cold dark matter (CDM) in the universe from WMAP, many supersymmetric models tend to predict 1. an overabundance of CDM and 2. pessimistically low rates for direct detection of neutralino dark matter. However, in models with a ``well-tempered neutralino'', where the neutrali

  99. Dimitris Kalles

    In this paper we experiment with a 2-player strategy board game where playing models are evolved using reinforcement learning and neural networks. The models are evolved to speed up automatic game development based on human involvement at varying levels of sophistication and density when compared to fully autonomous playing. The experimental results suggest

  100. K. Ozdogan, I. Galanakis, B. Aktas, E. Sasioglu

    In a recent publication [Galanakis I et al 2006 \PR B \textbf{74} 140408(R)] we have shown that in the case of CrAs and related transition-metal chalcogenides and pnictides, crystallizing in the zinc-blende structure, the excess of the transition-metal atoms leads to half-metallic ferrimagnetism. The latter property is crucial for spintronic applications wit