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September 2002 arXiv papers — page 11

Showing 1,001–1,100 of 3,263 papers

  1. C. P. Dettmann

    Recently, stretched exponential decay of multiple correlations in the periodic Lorentz gas has been used to show the convergence of a series of correlations which has the physical interpretation as the fourth order Burnett coefficient, a generalisation of the diffusion coefficient. Here the result is extended to include all higher order Burnett coefficients,

  2. Joel Feldman, Horst Knoerrer, Eugene Trubowitz

    We show that the particle number density derived from the thermodynamic Green's function at temperature zero constructed in the second part of this series has a jump across the Fermi curve, a basic property of a Fermi liquid. We further show that the two particle thermodynamic Green's function at temperature zero has the regularity behavior expected

  3. Joel Feldman, Horst Knoerrer, Eugene Trubowitz

    Using results established in other papers in our series, we prove the existence of the infinite volume, temperature zero, thermodynamic Green's functions of a two dimensional, weakly coupled fermion gas with an asymmetric Fermi curve and short range interactions. This is done by showing that our sequence of renormalization group maps converges.

  4. Joel Feldman, Horst Knoerrer, Eugene Trubowitz

    In a series of ten papers, of which this is the first, we prove that the temperature zero renormalized perturbation expansions of a class of interacting many-fermion models in two space dimensions have nonzero radius of convergence. The models have "asymmetric" Fermi surfaces and short range interactions. One consequence of the convergence of the per

  5. Joel Feldman, Horst Knoerrer, Eugene Trubowitz

    We improve on the abstract estimate obtained in Part 1 by assuming that there are constraints imposed by `overlapping momentum loops'. These constraints are active in a two dimensional, weakly coupled fermion gas with a strictly convex Fermi curve. The improved estimate is used in another paper to control everything but the sum of all ladder contribution

  6. Joel Feldman, Horst Knoerrer, Eugene Trubowitz

    An estimate on the operator norm of an abstract fermionic renormalization group map is derived. This abstract estimate is applied in another paper to construct the thermodynamic Green's functions of a two dimensional, weakly coupled fermion gas with an asymmetric Fermi curve. The estimate derived here is strong enough to control everything but the sum of

  7. Joel Feldman, Horst Knoerrer, Eugene Trubowitz

    A self contained analysis demonstrates that the sum of all particle-hole ladder contributions for a two dimensional, weakly coupled fermion gas with a strictly convex Fermi curve at temperature zero is bounded. This is used in our construction of two dimensional Fermi liquids.

  8. Joel Feldman, Horst Knoerrer, Eugene Trubowitz

    For a two dimensional, weakly coupled system of fermions at temperature zero, one principal ingredient used to control the composition of the associated renormalization group maps is the careful counting of the number of quartets of sectors that are consistent with conservation of momentum. A similar counting argument is made to show that particle-particle l

  9. Joel Feldman, Horst Knoerrer, Eugene Trubowitz

    The generic renormalization group map associated to a weakly coupled system of fermions at temperature zero is treated by supplementing the methods of Part 1. The interplay between position and momentum space is captured by `sectors'. It is shown that the difference between the complete four legged vertex and its `ladder' part is irrelevant for the s

  10. Joel Feldman, Horst Knoerrer, Eugene Trubowitz

    The first renormalization group map arising from the momentum space decomposition of a weakly coupled system of fermions at temperature zero differs from all subsequent maps. Namely, the component of momentum dual to temperature may be arbitrarily large - there is no ultraviolet cutoff. The methods of Part 1 are supplemented to control this special case.

  11. Joel Feldman, Horst Knoerrer, Eugene Trubowitz

    We construct, using fermionic functional integrals, thermodynamic Green's functions for a weakly coupled fermion gas whose Fermi energy lies in a gap. Estimates on the Green's functions are obtained that are characteristic of the size of the gap. This prepares the way for the analysis of single scale renormalization group maps for a system of fermion

  12. Marie A. Vitulli

    In this paper we investigate the question of normality for special monomial ideals in a polynomial ring over a field. We first include some expository sections that give the basics on the integral closure of a ideal, the Rees algebra on an ideal, and some fundamental results on the integral closure of a monomial ideal.

  13. Laurent Berger

    The purpose of this article is to give formulas for Bloch-Kato's exponential map and its dual for an absolutely crystalline p-adic representation V, in terms of the (phi,Gamma)-module associated to that representation. As a corollary of these computations, we can give a very simple (and slightly improved) description of Perrin-Riou's exponential map (which i

  14. Mario Catalani

    We propose two algorithms for sampling from two gamma variates possessing a negative correlation. The case of positive correlation is easily solved, so we just mention it. The main problem is the lowest value of the correlation coefficient that can be reached. The starting point of both algorithms is generation from a bivariate density with uniform negativel

  15. Uwe Nagel

    Extending results for space curves we establish bounds for the cohomology of a non-degenerate curve in projective $n$-space. As a consequence, for any given $n$ we determine all possible pairs $(d, g)$ where $d$ is the degree and $g$ is the (arithmetic) genus of the curve. Furthermore, we show that curves attaining our bounds always exist and describe proper

  16. Sachiko Takeuchi, Kiyotaka Shimizu

    Pauli-Blocking effect on the kinetic term is investigated by employing the quark cluster model. The effect can be understood by the change of the degrees of the mixing between the incoming wave and the 0$\ell$ state of the inter-cluster wave function, which can be expressed by a potential which is highly nonlocal. We look into the properties of this effect b

  17. A. Abada, K. Bouakaz

    We calculate the fermion damping rate to second order in powers of the external momentum $p$ in the context of QED at finite temperature using the hard-thermal-loop (HTL) summation scheme. We find that the coefficient of order $p^{2}$ is divergent in the infrared whereas the two others are finite. This result suggests that the htl-based pertubation is infrar

  18. R. D. Peccei

    The necessary complex structures needed for CP violation are not easy to generate and, indeed, CP can be a symmetry in higher dimensional theories. In 4-dimensions CP violation argues for the existence of a scalar sector and, in its simplest manifestation, leads to the CKM model. Further CP violating phases, from an extended scalar sector, are constrained by

  19. Thomas R. Hemmert, Wolfram Weise

    We calculate the quark mass dependence of both isovector and isoscalar anomalous magnetic moments of the nucleon in a chiral effective field theory with explicit pion, nucleon and Delta(1232) degrees of freedom to leading-one-loop order. In the isovector sector we fit 3 unknown couplings of the effective Lagrangian to available lattice data and obtain a surp

  20. M. C. Fujiwara, M. Marchesotti

    A novel system to monitor the intensity and the stability of a bunched beam of $\simeq 1.2\times 10^{7}$ antiprotons ($\bar{p}$s) with a length of $\simeq$ 250 ns (FWHM) and to measure its trapping efficiency in a Penning trap is described. This system operates parasitically detecting the pions from the annihilation of part of the beam in a degrader. Six pla

  21. P. Azzurri

    The measurements of four-fermion production rates performed at LEP2 in e+e- collisions at centre-of-mass energies ranging from 161 to 209 GeV are presented. The focus is put on processes that involve the production and decay of W or Z electroweak bosons. Results on W decay rates and couplings are also discussed.

  22. A. B. McDonald

    Present results and future measurements of solar neutrinos are discussed. The results to date indicate that solar electron neutrinos are changing to other active types and that transitions solely to sterile neutrinos are disfavored. The flux of $^{8}B$ solar neutrinos produced in the Sun, inferred assuming only active neutrino types, is found to be in very g

  23. Paul R. Anderson, Carmen Molina-Paris, Emil Mottola

    A quantitative test for the validity of the semi-classical approximation in gravity is given. The criterion proposed is that solutions to the semi-classical Einstein equations should be stable to linearized perturbations, in the sense that no gauge invariant perturbation should become unbounded in time. A self-consistent linear response analysis of these per

  24. Nematollah Riazi, Hassan Niad

    We formulate the nonlinear isovector model in a curved background, and calculate the spherically symmetric solutions for weak and strong coupling regimes. The usual belief that gravity does not have appreciable effects on the structure of solitons will be examined, in the framework of the calculated solutions, by comparing the flat-space and curved-space sol

  25. Mema Roussopoulos, Mary Baker

    This paper studies the problem of load-balancing the demand for content in a peer-to-peer network across heterogeneous peer nodes that hold replicas of the content. Previous decentralized load balancing techniques in distributed systems base their decisions on periodic updates containing information about load or available capacity observed at the serving en

  26. Simon W. Marlow, Peter D. Olmsted

    The effect of strong shear flow on highly fluctuating lamellar systems stabilized by intermembrane collisions via the Helfrich interaction is studied. Advection enters the microscopic equation of motion for a single membrane via a non-linear coupling. Upon coarse-graining the theory for a single bilayer up to the length scale of the collision length, at whic

  27. L. S. Levitov, E. I. Rashba

    Due to the spin-orbital coupling in a semiconductor quantum dot, a freely precessing electron spin produces a time-dependent charge density. This creates a sizeable electric field outside the dot, leading to promising applications in spintronics. The spin-electric coupling can be employed for non-invasive single spin detection by electrical methods. We also

  28. J. P. Huang, K. W. Yu

    Theoretical investigations on electrorheological (ER) fluids usually rely on computer simulations. An initial approach for these studies would be the point-dipole (PD) approximation, which is known to err considerably when the particles approach and finally touch due to many-body and multipolar interactions. Thus various work attempted to go beyond the PD mo

  29. N. I. Lebovka, S. S. Manna, S. Tarafdar, N. Teslenko

    We have studied the percolation behaviour of deposits for different (2+1)-dimensional models of surface layer formation. The mixed model of deposition was used, where particles were deposited selectively according to the random (RD) and ballistic (BD) deposition rules. In the mixed one-component models with deposition of only conducting particles, the mean h

  30. V. Laugalys, V. Straizys

    Magnitudes and color indices in the Vilnius seven-color system are measured for 690 stars down to ~13.2 mag in the area of the North America and Pelican nebulae. Spectral types, absolute magnitudes, color excesses, interstellar extinctions and distances of the stars are determined. The plots of interstellar extinction Av versus distance for the North America

  31. V. Straizys, K. Cernis, A. Kazlauskas, V. Laugalys

    Photoelectric magnitudes and color indices in the Vilnius seven-color system for 152 stars are used to investigate the interstellar extinction in the area of the Aries molecular cloud MBM 12, coinciding with the L1454 and L1457 dust clouds. Spectral types, absolute magnitudes, color excesses, interstellar extinctions and distances of the stars are determined

  32. F. Lucarelli, A. Konopelko, F. Aharonian, W. Hofmann

    Routine observations of the Crab Nebula for a total of about 250 hrs, performed with the HEGRA stereoscopic system of 5 imaging atmospheric Cerenkov telescopes in the standard operational mode, have proven the energy threshold of the system to be 500 GeV for small zenith angles (< 20 deg). A topological trigger applied along with the convergent observational

  33. A. Kazlauskas, K. Cernis, V. Laugalys, V. Straizys

    The results of photoelectric photometry in the Vilnius seven-color system are given for 152 stars down to 12.2 mag in the area of the molecular cloud MBM 12 and the dust clouds L1454 and L1457 in Aries. The results of photometric classification of stars are also given. The investigation of interstellar extinction in the area is described in the next paper.

  34. J. M. Stil, F. P. Israel

    We present WSRT observations of high sensitivity and resolution of the neutral hydrogen in the starburst dwarf galaxy NGC 1569. Assuming a distance of 2.2 Mpc, we find a total HI mass of 1.3 * 10^8 M_sun to be distributed in the form of a dense, clumpy ridge surrounded by more extended diffuse HI containing a few additional discrete features, such as a Weste

  35. Ujjaini Alam, Varun Sahni

    Braneworld models of dark energy are examined in the light of observations of high redshift type Ia supernovae. Braneworld models admit several novel and even exotic possibilities which include: (i) The effective equation of state of dark energy can be more negative than in LCDM: $w \leq -1$; (ii) A class of braneworld models can encounter a `quiescent&#39;

  36. Youichi Ohyama, Yoshiaki Taniguchi, Masanori Iye, Michitoshi Yoshida

    We present new optical images ($B$, $V$, and H$α$) of the archetypical starburst/superwind galaxy M82 obtained with the 8.2 m Subaru Telescope to reveal new detailed structures of the superwind-driven nebula and the high-latitude dark lanes. The emission-line nebula is decomposed into (1) a ridge-dominated component comprising numerous filament/loop sub-stru

  37. D. K. Srivastava, C. Gale, R. J. Fries

    We calculate the emission of large mass dileptons originating from the annihilation of quark jets passing through quark gluon plasma. Considering central collisions of heavy nuclei at SPS, RHIC and LHC energies, we find that the yield due to the jet-plasma interaction gets progressively larger as the collision energy increases. We find it to be negligible at

  38. Kari Enqvist, Anupam Mazumdar

    We review the cosmological implications of the flat directions of the Minimally Supersymmetric Standard Model (MSSM). We describe how field condensates are created along the flat directions because of inflationary fluctuations. The post-inflationary dynamical evolution of the field condensate can charge up the condensate with B or L in a process known as Aff

  39. Ben O&#39;Shaughnessy, Dimitrios Vavylonis

    Physisorption or chemisorption from dilute polymer solutions often entails irreversible polymer-surface bonding. We present a theory of the non-equilibrium layers which result. While the density profile and loop distribution are the same as for equilibrium layers, the final layer comprises a tightly bound inner part plus an outer part whose chains make only

  40. Harvey B. Meyer

    We propose a multilevel Monte-Carlo scheme, applicable to local actions, which is expected to reduce statistical errors on correlation functions. We give general arguments to show how the efficiency and parameters of the algorithm are determined by the low-energy spectrum. As an application, we measure the euclidean-time correlation of pairs of Wilson loops

  41. Michael Krasnitz

    We study fluctuations around the warped conifold supergravity solution of Klebanov and Tseytlin [hep-th/0002159], known to be dual to a cascading N=1 gauge theory. Although this supergravity background is not asymptotically AdS, corresponding to a non-conformal field theory, it is possible to apply the usual methods of AdS/CFT duality to extract the high ene

  42. E. Dudas, J. Mourad, C. Timirgaziu

    We investigate maximally symmetric backgrounds in nonsupersymmetric string vacua with D-branes and O-planes localized in the compact space. We find a class of solutions with a perturbative string coupling constant in all regions of spacetime. Depending on the particular model, we find either a time evolution with a big-bang type singularity or a space depend

  43. E. Del Gado, A. Fierro, L. de Arcangelis, A. Coniglio

    We investigate the slow dynamics in gelling systems by means of MonteCarlo simulations on the cubic lattice of a minimal statistical mechanics model. By opportunely varying some model parameter we are able to describe a crossover from the chemical gelation behaviour to dynamics more typical of colloidal systems. The results suggest a novel connection linking

  44. R. C. Berrington, C. D. Dermer

    We have developed a numerical model for the temporal evolution of particle and photon spectra resulting from nonthermal processes at the shock fronts formed in merging clusters of galaxies. Fermi acceleration is approximated by injecting power-law distributions of particles during a merger event, subject to constraints on maximum particle energies. We consid

  45. Chung Wen Kao, Thomas Spitzenberg, Marc Vanderhaeghen

    We study spin-dependent sum rules for forward virtual Compton scattering(VVCS) off the nucleon in heavy baryon chiral perturbation theory at order $O(p^4)$. We show how these sum rules can be evaluated from low energy expansions (in the virtual photon energy) of the forward VVCS amplitudes. We study in particular the Burkhardt -Cottingham sum rule in HBChPT

  46. S. Piatek, C. Pryor, E. W. Olszewski, H. C. Harris

    This article presents and discusses a method for measuring the proper motions of the Galactic dwarf spheroidal galaxies using images taken with the Hubble Space Telescope. The method involves fitting an effective point spread function to the image of a star or quasi-stellar object to determine its centroid with an accuracy of about 0.005 pixel (0.25 milliarc

  47. Alessandra Agostini, Fedele Lizzi, Alessandro Zampini

    We introduce the notion of generalized Weyl system, and use it to define *-products which generalize the commutation relations of Lie algebras. In particular we study in a comparative way various *-products which generalize the k-Minkowski commutation relations.

  48. P. M. Hajac, R. Matthes, W. Szymanski

    We consider two Z/2Z-actions on the Podles generic quantum spheres. They yield, as noncommutative quotient spaces, the Klimek-Lesniewski q-disc and the quantum real projective space, respectively. The C*-algebras of all these quantum spaces are described as graph C*-algebras. The K-groups of the thus presented C*-algebras are then easily determined from the

  49. D. Garber, S. Kaplan, M. Teicher, B. Tsaban

    Several key agreement protocols are based on the following &#34;Generalized Conjugacy Search Problem&#34;: Find, given elements b_1,...,b_n and xb_1x^{-1},...,xb_nx^{-1} in a nonabelian group G, the conjugator x. In the case of subgroups of the braid group B_N, Hughes and Tannenbaum suggested a length-based approach to finding x. Since the introduction of th

  50. J. Engels, L. Fromme, M. Seniuch

    We study an improved three-dimensional Ising model with external magnetic field near the critical point by Monte Carlo simulations. From our data we determine numerically the universal scaling functions of the magnetization, that is the equation of state, of the susceptibility and of the correlation length. In order to normalize the scaling functions we calc

  51. Oleg P. Makarov, R. Côté, H. Michels, W. W. Smith

    New experiments were proposed recently to investigate the regime of cold atomic and molecular ion-atom collision processes in a special hybrid neutral-atom--ion trap under high vacuum conditions. The collisional cooling of laser pre-cooled Ca$^+$ ions by ultracold Na atoms is being studied. Modeling this process requires knowledge of the radiative lifetime o

  52. Yoshiyuki Morisawa, Daisuke Ida, Akihiro Ishibashi, Ken-ichi Nakao

    We discuss the gravitationally interacting system of a thick domain wall and a black hole. We numerically solve the scalar field equation in the Schwarzschild spacetime and obtain a sequence of static axi-symmetric solutions representing thick domain walls. We find that, for the walls near the horizon, the Nambu--Goto approximation is no longer valid.

  53. Semyon Alesker

    We obtain new general results on the structure of the space of translation invariant continuous valuations on convex sets (a version of the hard Lefschetz theorem). Using these and our previous results we obtain explicit characterization of unitarily invariant translation invariant continuous valuations. It implies new integral geometric formulas for real su

  54. Elena Poletaeva

    We observe a correspondence between the zero modes of superconformal algebras $S&#39;(2, 1)$ and W(4) and the Lie superalgebras formed by classical operators appearing in the K{ä}hler and hyper-K{ä}hler geometry.

  55. B. Ercolano, C. Morisset, M. J. Barlow, P. J. Storey

    The three-dimensional Monte Carlo photoionization code Mocassin has been applied to construct a realistic model of the planetary nebula NGC 3918. Three different geometric models were tried. The effects of the interaction of the diffuse fields coming from two adjacent regions of different densities were investigated. These are found to be non-negligible, eve

  56. C. Duval, P. A. Horvathy

    A slightly modified and regularized version of the non-relativistic limit of the relativistic anyon model considered by Jackiw and Nair yields particles associated with the twofold central extension of the Galilei group, with independent spin and exotic structure.

  57. M. Yu. Kagan, I. V. Brodsky, D. V. Efremov, A. V. Klaptsov

    We consider a model of Fermi-Bose mixture with strong hard-core repulsion between particles of the same sort and attraction between particles of different sorts. In this case, besides the standard anomalous averages of the type $<b>$; $<bb>$ and $<cc>$, a pairing between fermion and boson of the type $bc$ is possible. This pairing corresponds to a creation o

  58. Herbert Müther, Armen Sedrakian

    Isoscalar Cooper pairing in isospin asymmetric nuclear matter occurs between states populating two distinct Fermi surfaces, each for neutrons and protons. The transition from a BCS-like to the normal (unpaired) state, as the isospin asymmetry is increased, is intervened by superconducting phases which spontaneously break translational and rotational symmetri

  59. Dongsheng Du, Junfeng Sun, Deshan Yang, Guohuai Zhu

    In this paper, we perform a global analysis of $B \to PP$ and $PV$ decays with the QCD factorization approach. It is encouraging to observe that the predictions of QCD factorization are in good agreement with experiment. The best fit $γ$ is around $79^\circ$. The penguin-to-tree ratio $|P_{ππ}/T_{ππ}|$ of $π^+ π^-$ decays is preferred to be larger than 0.3.

  60. Yu-Hong Tan, Ping-Zhi Ning

    We demonstrate the different effect of strange impurities ($Λ$ and $Ξ$) on the static properties of nuclei within the framework of the relativistic mean-field model. Systematic calculations show that the gluelike role of $Λ$ hyperon is universal for all $Λ$-hypernuclei considered. However, $Ξ^-$ hyperon has the gluelike role only for the protons distribution

  61. David d&#39;Enterria

    Neutral pions with p_T = 1 - 8 GeV/c have been measured for 9 different centrality classes in Au+Au collisions at sqrt(s_NN) = 200 GeV by the PHENIX experiment at RHIC. The pi^0 multiplicity in central reactions is significantly below the binary collision scaled yields from both peripheral Au+Au and pp reactions. The observed suppression sets in for the 50-7

  62. M. Takeda, N. Sakaki, K. Honda, M. Chikawa

    Using data from more than ten-years of observations with the Akeno Giant Air Shower Array (AGASA), we published a result that the energy spectrum of ultra-high energy cosmic rays extends beyond the cutoff energy predicted by Greisen, and Zatsepin and Kuzmin. In this paper, we reevaluate the energy determination method used for AGASA events with respect to th

  63. P. Kumar, X. Li, M. Fiorentino, P. L. Voss

    We present a fiber-based source of polarization-entangled photon pairs that is well suited for quantum communication applications in the 1.5$μ$m band of standard telecommunication fiber. Quantum-correlated signal and idler photon pairs are produced when a nonlinear-fiber Sagnac interferometer is pumped in the anomalous-dispersion region of the fiber. Recentl

  64. Qiu Jian, Ru-Keng Su

    A Wronskian determinant approach is suggested to study the energy and the wave function for one-dimensional Schrodinger equation. An integral equation and the corresponding Green&#39;s function are constructed. As an example, we employed this approach to study the problem of double-well potential with strong coupling. A series expansion of ground state energ

  65. Izumi Tsutsui, Tamas Fulop, Taksu Cheon

    To describe a quantum system whose potential is divergent at one point, one must provide proper connection conditions for the wave functions at the singularity. Generalizing the scheme used for point interactions in one dimension, we present a set of connection conditions which are well-defined even if the wave functions and/or their derivatives are divergen

  66. Wayne C. Myrvold

    A proof is given, at a greater level of generality than previous &#39;no-go&#39; theorems, of the impossibility of formulating a modal interpretation that exhibits &#39;serious&#39; Lorentz invariance at the fundamental level. Particular attention is given to modal interpretations of the type proposed by Bub.

  67. Dominic W. Berry, Barry C. Sanders

    We propose a feedback scheme for the production of two-mode spin squeezing. We determine a general expression for the optimal feedback, which is also applicable to the case of single-mode spin squeezing. The two-mode spin squeezed states obtained via this feedback are optimal for j=1/2 and are very close to optimal for j>1/2. In addition, the master equation

  68. Michael H. Freedman, Alexei Kitaev, Michael J. Larsen, Zhenghan Wang

    The theory of quantum computation can be constructed from the abstract study of anyonic systems. In mathematical terms, these are unitary topological modular functors. They underlie the Jones polynomial and arise in Witten-Chern-Simons theory. The braiding and fusion of anyonic excitations in quantum Hall electron liquids and 2D-magnets are modeled by modula

  69. Wentian Li, Pedro Bernaola-Galvan, Pedro Carpena, Jose L Oliver

    The isochore concept in human genome sequence was challenged in an analysis by the International Human Genome Sequencing Consortium (IHGSC). We argue here that a statement in IGHSC analysis concerning the existence of isochore is incorrect, because it had applied an inappropriate statistical test. To test the existence of isochores should be equivalent to a

  70. James D. Brownridge, Stephen M. Shafroth

    Pyroelectric crystals are used to produce self-focused electron beams with energies greater than 170 keV. No high voltage power supply or electron gun is needed. The system works by simply changing the temperature of a crystal of LiNbO3 or LiTaO3 by about 100oC in dilute gas. Electron beam energy spectra as well as positive-ion-beam energy spectra and profil

  71. B. Zilbergleyt

    The article presents results of preliminary study of solutions to recently offered basic thermodynamic equation for equilibrium in chemical systems with focus on chaotic behavior. Classical part of that equation was investigated earlier in a series of papers. In this work a similarity between one-dimensional logistic map and non-classical (chaotic) term of t

  72. V. Bezak

    The Waxman-Peck theory of the population genetics is discussed in regard of soil bacteria. Each bacterium is understood as a carrier of a phenotypic parameter p. The central aim is the calculation of the probability density with respect to p of the carriers living at time t>0. The theory involves two small parameters: the mutation probability $μ$ and a param

  73. J. A. Dharmadhikari, A. K. Dharmadhikari, Alpana. Mishra, G. Ravindra Kumar

    We study forward stimulated Raman emission from weakly fluorescent dye 4&#39;-diethylamino-N-methyl-4-stilbazolium tosylate (DEST) in 1,2,dichloroethane solution excited by a 28 ps, 532 nm Nd: YAG laser. Neat 1, 2, dichloroethane emits the first Stokes line at 631 nm with a spectral width of 1.6 nm corresponding to a Raman shift of 2956 per cm. We observe re

  74. N. Baboi, R. M. Jones, J. W. Wang, G. B. Bowden

    Dipole modes are the main cause of transverse emittance dilution in the Japanese Linear Collider / Next Linear Collider (JLC/NLC). A diagnostic setup has been built in order to investigate them. The method is based on using a coaxial wire to excite and measure electromagnetic modes of accelerating structures. This method can offer a more efficient and less e

  75. M. M. Brisudova, T. Goldman

    We study the mixing of excited states of a Hydrogen atom in a cavity with de-excited states plus a confined photon as a model for the coupling of quark-antiquark and quark-antiquark-gluon hybrid states in QCD. For an interesting range of parameters, the results are analytic. We find a case for which wavefunctions (and hence decay patterns) may be at odds wit

  76. W. H. Klink

    Free current operators are constructed for massive particles with arbitrary spin $j$. Such current operators are related to representations of the U(N,N) type groups and are covariant under the (extended) Poincaré group and charge conjugation, where the charge conjugation operation is defined as an automorphism on U(N,N) elements. The currents are also requi

  77. M. A. Maize

    In a paper published in A.J.P. by Coutinho, Nogami and Tomio, two definitions of the relativistic electric polarizability were introduced and discussed. The analyses and conclusions of the authors contain a fair number of serious mistakes. It is our purpose to correct any misunderstanding that might result from the errors appearing in their paper.

  78. C. Barbero, D. Horvat, F. Krmpotic, T. T. S. Kuo

    A general shell model formalism for the nonmesonic weak decay of the hypernuclei has been developed. It involves a partial wave expansion of the emitted nucleon waves, preserves naturally the antisymmetrization between the escaping particles and the residual core, and contains as a particular case the weak $Λ$-core coupling formalism. The Extreme Particle-Ho

  79. Jean-Luc Thiffeault, Allen H. Boozer

    The kinematic regime of the magnetic dynamo neglects the backreaction of the magnetic field on the flow. For small magnetic diffusivity, in the early stage of evolution, there is an ideal phase where dissipative effects can also be neglected. We estimate the magnitude of the energy dissipation term (Ohmic heating), taking into account differential constraint

  80. John Cardy

    An exact formula is given for the probability that there exists a spanning cluster between opposite boundaries of an annulus, in the scaling limit of critical percolation. The entire distribution function for the number of distinct spanning clusters is also given. These results are found using Coulomb gas methods. Their forms are compared with the expectatio

  81. Michael K. Kinyon, Kenneth Kunen, J. D. Phillips

    Let $Q$ be a conjugacy closed loop, and $N(Q)$ its nucleus. Then $Z(N(Q))$ contains all associators of elements of $Q$. If in addition $Q$ is diassociative (i.e., an extra loop), then all these associators have order 2. If $Q$ is power-associative and $|Q|$ is finite and relatively prime to 6, then $Q$ is a group. If $Q$ is a finite non-associative extra loo

  82. J. Huang, I. Kontoyiannis, S. P. Meyn

    We give a development of the ODE method for the analysis of recursive algorithms described by a stochastic recursion. With variability modelled via an underlying Markov process, and under general assumptions, the following results are obtained: 1. Stability of an associated ODE implies that the stochastic recursion is stable in a strong sense when a gain par

  83. Miklós Bóna, Bruce E. Sagan

    Simion conjectured the unimodality of a sequence counting lattice paths in a grid with a Ferrers diagram removed from the northwest corner. Recently, Hildebrand and then Wang proved the stronger result that this sequence is actually log concave. Both proofs were mainly algebraic in nature. We give two combinatorial proofs of this theorem.

  84. Karen E. Smith, Michel Van den Bergh

    Let W be a finite dimensional representation of a linearly reductive group G over a field k. Motivated by their work on classical rings of invariants, Levasseur and Stafford asked whether the ring of invariants under G of the symmetric algebra of W has a simple ring of differential operators. In this paper, we show that this is true in prime characteristic.

  85. David Wright, Wenhua Zhao

    Given a formal map $F=(F_1...,F_n)$ of the form $z+\text{higher}$ order terms, we give tree expansion formulas and associated algorithms for the D-Log of F and the formal flow F_t. The coefficients which appear in these formulas can be viewed as certain generalizations of the Bernoulli numbers and the Bernoulli polynomials. Moreover the coefficient polynomia

  86. Vyacheslav Krushkal

    The disk embedding lemma is a technique underlying the topological classification results in 4-manifold topology for good fundamental groups. The purpose of this paper is to develop new tools for disk embedding that work up to s-cobordism, without restrictions on the fundamental group. As an application we show that a surgery problem gives rise to a collecti

  87. Christian Krattenthaler

    A proof of an unusual summation formula for a basic hypergeometric series associated to the affine root system $\tilde A_n$ that was conjectured by Warnaar is given. It makes use of Milne&#39;s $A_n$ extension of Watson&#39;s transformation, Ramanujan&#39;s $_1ψ_1$-summation, and a determinant evaluation of the author. In addition, a transformation formula b

  88. Cornelius Griffin

    It is known from work of du Sautoy and Grunewald in \cite{duSG1} that the zeta functions counting subgroups of finite index in infinite nilpotent groups depend upon the behaviour of some associated system of algebraic varieties on reduction $\modp.$ Further to this, in \cite{duS3, duS4} du Sautoy constructed a group whose local zeta function was determined b

  89. T. Elsken, M. Prizzi

    A reaction-diffusion equation on a family of three dimensional thin domains, collapsing onto a two dimensional subspace, is considered. In \cite{\rfa pr..} it was proved that, as the thickness of the domains tends to zero, the solutions of the equations converge in a strong sense to the solutions of an abstract semilinear parabolic equation living in a close

  90. Mario Catalani

    We consider a sequence of sums of powers of the the roots of the cubic equation characterizing the Tribonacci sequences and derive its relationship with a particular Tribonacci sequence. Then we make a conjecture on the possible generalization.

  91. Frans oort, Thomas Zink

    A p-divisible group over a base scheme in characteristic p in general does not admit a slope filtration. Let X be a p-divisible group with constant Newton polygon over a normal noetherian scheme S; we prove that there exists an isogeny from X to Y such that Y admits a slope filtration. In case S is regular this was proved by N. Katz for dim(S) = 1 and by T.

  92. O. I. Mokhov

    We prove that the description of pencils of compatible (N x N)-metrics of constant Riemannian curvature is equivalent to a special class of integrable N-parametric deformations of quasi-Frobenius (in general, noncommutative) algebras.

  93. Andriy Panasyuk

    Given a 1-parameter family of 1-forms $\g(t)= \g_0+t\g_1+...+t^n\g_n$, consider the condition $d\g(t)\wedge\g(t)=0$ (of integrability for the annihilated by $\g(t)$ distribution $w(t)$). We prove that in order that this condition is satisfied for any $t$ it is sufficient that it is satisfied for $N=n+3$ different values of $t$ (the corresponding implication

  94. Andriy Panasyuk

    We propose a method of constructing completely integrable systems based on reduction of bihamiltonian structures. More precisely, we give an easily checkable necessary and sufficient conditions for the micro-kroneckerity of the reduction (performed with respect to a special type action of a Lie group) of micro-Jordan bihamiltonian structures whose Nijenhuis

  95. Anna Fino, Maurizio Parton, Simon Salamon

    This paper classifies Hermitian structures on 6-dimensional nilmanifolds M=G/L for which the fundamental 2-form is d d-bar closed, a condition that is shown to depend only on the underlying complex structure J of M. The space of such J is described when G is the complex Heisenberg group, and explicit solutions are obtained from a limacon-shaped curve in the

  96. Yongwei Yao

    For finitely generated modules $N \subsetneq M$ over a Noetherian ring $R$, we study the following properties about primary decomposition: (1) The Compatibility property, which says that if $\ass (M/N)=\{P_1, P_2, ..., P_s\}$ and $Q_i$ is a $P_i$-primary component of $N \subsetneq M$ for each $i=1,2,...,s$, then $N =Q_1 \cap Q_2 \cap ... \cap Q_s$; (2) For a

  97. Markus Rosellen

    In hep-th/0010293 Kapustin and Orlov introduce the notion of an OPE-algebra and propose that it formalizes conformal field theories in the same way as vertex algebras formalize chiral algebras, i.e. the subalgebras of holomorphic fields of conformal field theories. In this thesis we study the question which concepts and results of the general theory of verte

  98. Kota Yoshioka

    In this note, we consider the problem on the preservation of stability under the Fourier-Mukai transforms. We first show that the Fourier-Mukai transform on an abelian surface or a K3 surface does not always preserve the stability, even for a $μ$-stable vector bundle. We next provide some positive results on this problem. Finally we discuss the birational ma

  99. George J. McNinch

    Let G be the six dimensional linear algebraic k-group SL_2(W_2), where W_2 is the ring of Witt vectors of length two over the algebraically closed field k of characteristic p>2. Then the minimal dimension of a faithful rational k-representation of G is p+3.

  100. Ruben Mkrtchyan

    The construction of field theories with space-time symmetries, including tensorial charges (i.e. of M-theory type), initiated in hep-th/9907011, is extended to include interaction. For SO(2,2) gravity in a tensorial space-time, with space-time symmetry consisting of Lorentz generators and &#34;translations&#34;, represented by second-rank antisymmetric tenso