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May 1997 arXiv papers — page 13

Showing 1,201–1,300 of 1,580 papers

  1. Harrison J. Sheinblatt

    A black hole solution to low energy type IIA string theory which is extremal, non-supersymmetric, and carries 0- and 6-brane charge is presented. For large values of the charges it is metastable and a corresponding D-brane picture can be found. The mass and statistical entropy of the two descriptions agree at a correspondence point up to factors of order one

  2. Savdeep Sethi, Mark Stern

    We study the existence of D-brane bound states at threshold in Type II string theories. In a number of situations, we can reduce the question of existence to quadrature, and the study of a particular limit of the propagator for the system of D-branes. This involves a derivation of an index theorem for a family of non-Fredholm operators. In support of the con

  3. Juan M. Maldacena

    We calculate the one loop effective action for D-brane probes moving in the presence of near BPS D-branes. The $v^2$ term agrees with supergravity in all cases and the static force agrees for a five dimensional black hole with two large charges. It also agrees qualitatively in all the other cases. We make some comments on the M(atrix) theory interpretation o

  4. Rama Cont

    The statistical properties of the increments x(t+T) - x(t) of a financial time series depend on the time resolution T on which the increments are considered. A non-parametric approach is used to study the scale dependence of the empirical distribution of the price increments x(t+T) - x(t) of S&P Index futures, for time scales T, ranging from a few minutes to

  5. Subir Sachdev

    We present a unified, global perspective on the magnetic properties of strongly disordered electronic systems, with special emphasis on the case where the ground state is metallic. We review the arguments for the instability of the disordered Fermi liquid state towards the formation of local magnetic moments, and argue that their singular low temperature the

  6. S. M. Barr

    It is shown, using a modification of an idea of Sen, that completely realistic supersymmetric grand-unified theories based on SU(6) or larger unitary groups can be constructed using the sliding-singlet mechanism. These models have a simple structure, preserve the successful prediction of $\sin^2 θ_W$, and can suppress Higgsino-mediated proton decay to an acc

  7. J. Blümlein, B. Geyer, D. Robaschik

    The non-singlet and singlet evolution kernels of the twist--2 light-ray operators for unpolarized and polarized deep inelastic scattering are calculated in $O(α_s)$ for the general case of virtualities $q^2, q'^2 \neq 0$. Special cases as the kernels for the general single-variable evolution equation and the Altarelli-Parisi and Brodsky-Lepage limits are

  8. V. Aldaya, M. Calixto, J. M. Cervero

    The underlying reasons for the difficulty of unitarily implementing the whole conformal group $SO(4,2)$ in a massless Quantum Field Theory (QFT) are investigated in this paper. Firstly, we demonstrate that the singular action of the subgroup of special conformal transformations (SCT), on the standard Minkowski space $M$, cannot be primarily associated with t

  9. Yukitoshi Motome, Masatoshi Imada

    We present a framework of an auxiliary field quantum Monte Carlo (QMC) method for multi-orbital Hubbard models. Our formulation can be applied to a Hamiltonian which includes terms for on-site Coulomb interaction for both intra- and inter-orbitals, intra-site exchange interaction and energy differences between orbitals. Based on our framework, we point out p

  10. Tomo Munehisa, Yasuko Munehisa

    An extended Hubbard model on a two-leg ladder is numerically studied by means of the quantum Monte Carlo techniques. The model we study has the nearest-neighbor interactions which are repulsive along chains and attractive for rungs. The plots of the doping parameter versus the chemical potential show two cliff-like regions and a large plateau region. Results

  11. J. David Moroz, Randall D. Kamien

    We map self-avoiding random walks with a chemical potential for writhe to the three-dimensional complex O(N) Chern-Simons theory as N -> 0. We argue that at the Wilson-Fisher fixed point which characterizes normal self-avoiding walks (with radius of gyration exponent nu = 0.588) a small chemical potential for writhe is irrelevant and the Chern-Simons field d

  12. C. D'Helon, G. J. Milburn

    We present a scheme in which an ion trap quantum computer can be used to make arbitrarily accurate measurements of the quadrature phase variables for the collective vibrational motion of the ion. The electronic states of the ion become the `apparatus', and the method is based on regarding the `apparatus' as a quantum computer register which can be pr

  13. Christoph Puntmann

    We derive Gamow vectors from S-matrix poles of higher multiplicity in analogy to the Gamow vectors describing resonances from first-order poles. With these vectors we construct a density operator that describes resonances associated with higher order poles that obey an exponential decay law. It turns out that this operator formed by these higher order Gamow

  14. C. Puntmann, P. Patuleanu

    In analogy to Gamow vectors describing resonance states from first order S-matrix poles, one can define Gamow vectors from higher order poles of the S-matrix. With these vectors we are going to discuss a density operator that describes exponentially decaying resonances from higher order poles.

  15. Vadim B. Kuznetsov, Evgueni K. Sklyanin

    We show that the method of separation of variables gives a natural generalisation of integral relations for classical special functions of one variable. The approach is illustrated by giving a new proof of the ``quadratic'' integral relations for the continuous q-ultraspherical polynomials. The separating integral operator M expressed in terms of the

  16. Thomas C. Halsey

    I analyze the topological structures generated by diffusion-limited aggregation (DLA), using the recently developed "branched growth model". The computed bifurcation number B for DLA in two dimensions is B ~ 4.9, in good agreement with the numerically obtained result of B ~ 5.2. In high dimensions, B -> 3.12; the bifurcation ratio is thus a decreasin

  17. S. A. Sofianos, S. A. Rakityansky, G. P. Vermaak

    Three- and four-neutron systems are studied within the framework of the hyperspherical approach with a local S-wave nn-potential. Possible bound and resonant states of these systems are sought as zeros of three- and four-body Jost functions in the complex momentum plane. It is found that zeros closest to the origin correspond to sub-threshold (nnn) (1/2-) an

  18. Dubravko Ivanšić

    It is known that the volume function for hyperbolic manifolds of dimension $\geq 3$ is finite-to-one. We show that the number of nonhomeomorphic hyperbolic 4-manifolds with the same volume can be made arbitrarily large. This is done by constructing a sequence of finite-sided finite-volume polyhedra with side-pairings that yield manifolds. In fact, we show th

  19. Renata Kallosh

    We have found that kappa-symmetry allows a covariant quantization provided the ground state of the theory is strictly massive. For D-p-branes a Hamiltonian analysis is performed to explain the existence of a manifestly supersymmetric and Lorentz covariant description of the BPS states of the theory. The covariant quantization of the D-0-brane is presented as

  20. Petr Horava

    We consider compactifications of the matrix model of M-theory on $S^1/Z_2\times T^d$ for $d>0$, and interpret them as orbifolds of the supersymmetric U(N) Yang-Mills theory on $R\times T^{d+1}$. The orbifold group acts both on the gauge group and on the $T^{d+1}$, reduces the gauge group to O(N) over 1+1 dimensional fixed-point submanifolds, and breaks half

  21. S. Deser, L. Griguolo, D. Seminara

    The effective gauge field actions generated by charged fermions in $QED_3$ and $QCD_3$ can be made invariant under both small and large gauge transformations at any temperature by suitable regularization of the Dirac operator determinant, at the price of parity anomalies. We resolve the paradox that the perturbative expansion is not invariant, as manifested

  22. H. R. Karadayi, M. Gungormez

    It is well known that anomaly cancellations for D_16 Lie algebra are at the root of the first string revolution. For E_8 Lie algebra, cancellation of anomalies is the principal fact leading to the existence of heterotic string. They are in fact nothing but the 6th order cohomologies of corresponding Lie algebras. Beyond 6th order, the calculations seem to re

  23. E. J. Copeland, James E. Lidsey, David Wands

    We investigate the generation of curvature and isocurvature (dilaton, moduli and axion) perturbations in a general class of axion-dilaton-moduli models,including the pre-big bang scenario. Allowing for an arbitrary coupling constant between the dilaton field and the axion field, we exploit the SL(2,R) symmetry of the theory to obtain the spectral indices of

  24. R. R. Metsaev

    We present results of investigation into a problem of cubic interaction vertices of massless higher spin fields which transform in arbitrary irreps of the Poincare algebra

  25. Alexios P. Polychronakos

    We show that a particular many-matrix model gives rise, upon hamiltonian reduction, to a multidimensional version of the Calogero-Sutherland model and its spin generalizations. Some simple solutions of these models are demonstrated by solving the corresponding matrix equations. A connection of this model to the dimensional reduction of Yang-Mills theories to

  26. Hitoshi Murayama

    We present a simple model of gauge mediation (GM) which does not have a messenger sector or gauge singlet fields. The standard model gauge groups couple directly to the sector which breaks supersymmetry dynamically. This is the first phenomenologically viable example of this type in the literature. Despite the direct coupling, the model can preserve perturba

  27. Xuemin Jin, Jian Tang

    Two new QCD sum rules for nucleon tensor charge are derived from a mixed correlator of spin-1/2 and spin-3/2 nucleon interpolating fields. These sum rules are analyzed along with a sum rule obtained from the usual correlator of a general spin-1/2 nucleon interpolating field. The validity and reliability of the sum rules are examined by monitoring the contami

  28. S. E. Derkachov, J. A. Gracey, A. N. Manashov

    We compute the anomalous dimensions of a set of composite operators which involve derivatives at four loops in MSbar in phi^4 theory as a function of the operator moment n. These operators are similar to the twist-2 operators which arise in QCD in the operator product expansion in deep inelastic scattering. By regarding their inverse Mellin transform as bein

  29. G. Hellstern. R. Alkofer, M. Oettel, H. Reinhardt

    In a model where constituent quarks and diquarks interact through quark exchange the Bethe-Salpeter equation in ladder approximation for the nucleon is solved. Quark and diquark confinement is effectively parametrized by choosing appropriately modified propagators. The coupling to external currents is implemented via nontrivial vertex functions for quarks an

  30. S. M. Barr

    An approach to solving the Strong CP Problem in supersymmetric theories is discussed which uses abelian family symmetries to align the mass matrices of the quarks and squarks. In this way both the Strong CP Problem and the characteristic flavor and CP problems of supersymmetry can be solved in a single way.

  31. Eiichi Takasugi

    For three generations of quarks, we show that one of quark mass matrices can be transformed into either a Fritzsch form or a Branco-Silva-Marcos form, while the other is kept in the NNI basis. In these bases, quark mass matrices are determined unambiguously once quark masses and the CKM mixing are given.

  32. Michael Gronau

    CP violation in $B$ decays is reviewed in the Standard Model (SM) and beyond the SM. The present explanation of CP violation in terms of a phase in the Cabibbo-Kobayashi-Maskawa (CKM) matrix can be tested through a variety of CP asymmetries in neutral and charged $B$ decays. Usually, new mechanisms of CP nonconservation enter via $B-\bar{B}$ mixing and viola

  33. Urs M. Heller

    We discuss the Schrödinger functional in lattice QCD with staggered fermions including its order $O(a)$ boundary counterterms. We relate it, in the classical continuum limit, to the Schrödinger functional as obtained in the same limit with Wilson fermions. We compute the strong coupling constant defined via the Schrödinger functional with staggered fermions

  34. CLEO Collaboration, R. Balest et al

    Using e+e- annihilation data collected by the CLEO~II detector at CESR, we have observed the decay Ds+ to omega pi+. This final state may be produced through the annihilation decay of the Ds+, or through final state interactions. We find a branching ratio of [Gamma(Ds+ to omega pi+)/Gamma(Ds+ to eta pi+)]=0.16+-0.04+-0.03, where the first error is statistica

  35. CLEO Collaboration, B. Barish et al

    Using data collected in the region of the Upsilon(4S) resonance with the CLEO II detector operating at the Cornell Electron Storage Ring CESR, we present the first observation of B mesons decaying into the charmed strange baryons Xi_c0 and Xi_c+. We find 79 +/- 27 Xi_c0 and 125 +/- 28 Xi_c+ candidates from B decays, leading to product branching fractions of

  36. Stephen W. Leonard, Eric Poisson

    Radiative multipole moments of scalar, electromagnetic, and linearized gravitational fields in Schwarzschild spacetime are computed to third order in v in a weak-field, slow-motion approximation, where v is a characteristic velocity associated with the motion of the source. To zeroth order in v, a radiative moment of order l is given by the corresponding sou

  37. Prashant M. Gade, M. P. Joy

    We demonstrate the phenomenon of self organized criticality (SOC) in a simple random walk model described by a random walk of a myopic ant. The ant acts on the underlying lattice aiming at uniform digging of the surface but is unaffected by the underlying lattice. In 1-d, 2-d and 3-d we have explored this model and have obtained power laws in the time interv

  38. M. Pasquini, M. Serva

    In this paper we consider a 2d random Ising system on a square lattice with nearest neighbour interactions. The disorder is short range correlated and asymmetry between the vertical and the horizontal direction is admitted. More precisely, the vertical bonds are supposed to be non random while the horizontal bonds alternate: one row of all non random horizon

  39. Lin Tian, Ya-Sha Yi, Chui-Lin Wang, Zhao-Bin Su

    The electron-phonon interaction in $C_{70}$ anions is studied by making use of a lattice relaxation approach. We find there exists a Jahn-Teller effect in $C_{70}^{3-}$ system, due to an extra electron being doped to the double degenerate $E_{1}^{''}$ state. As a result of this effect, the original $D_{5h}$ symmetry of the ground state becomes unstab

  40. Tomotoshi Nishino, Kouichi Okunishi

    We report a real-space renormalization group (RSRG) algorithm, which is formulated through Baxter's corner transfer matrix (CTM), for two-dimensional (d = 2) classical lattice models. The new method performs the renormalization group transformation according to White's density matrix algorithm, so that variational free energies are minimized within a

  41. Georgios Varelogiannis, Martin Peter

    We make a harmonic analysis of the pairing and damping contribution of a finite $k$ range isotropic electron-phonon (or other boson) scattering in an anisotropic two-dimensional electronic system. We show that the pairing contribution of the anisotropic part of the electronic system can be much larger than its damping contribution enhancing significantly T_c

  42. Jan Harms, J. Peter Toennies, Franco Dalfovo

    The classical integral cross sections of large superfluid 4He_N droplets and the number of atoms in the droplets (N=10^3-10^4) have been measured in molecular beam scattering experiments. These measurements are found to be in good agreement with the cross sections predicted from density functional calculations of the radial density distributions with a 10-90

  43. D. Lidsky, J. Shiraishi, Y. Hatsugai, M. Kohmoto

    We generalize the model of Hatsugai and Kohmoto [J. Phys. Soc. Jpn, 61, 2056 (1992)] and find ground states which do not show the properties of Fermi liquids. We work in two space dimensions, but it is straightforward to generalize to higher dimensions. The ground state is highly degenerate and there is no discontinuity in the momentum distribution; i.e., th

  44. Y. -Z. Qian

    In a recent Letter, Kusenko and Segre proposed a new mechanism to explain the observed proper motions of pulsars. Their mechanism was based on the asymmetric neutrino emission induced by neutrino oscillations in the protoneutron star magnetic field. In this note I point out that their estimate of the asymmetry in the neutrino emission is incorrect. A proper

  45. Pablo Laguna, Alex Wolszczan

    We present a study of the gravitational time delay of arrival of signals from binary pulsar systems with rotating black hole companions. In particular, we investigate the strength of this effect (Shapiro delay) as a function of the inclination, eccentricity and period of the orbit, as well as the mass and angular momentum of the black hole. This study is bas

  46. M. S. Brotherton, Wil van Breugel, Arjun Dey, Robert Antonucci

    We present Keck spectropolarimetry of a rare ``Iron Lo-BALQSO,'' FIRST 0840+3633. The continuum is 4% polarized near 2000 angstroms rest-frame, but falls to 2% at longer wavelengths, and maintains a relatively constant position angle of 50 degrees. The emission lines are unpolarized. The polarization increases up to 8% in the low-ionization absorptio

  47. Julie D. Blum, Kenneth Intriligator

    We discuss type II and type I branes at general ADE type orbifold singularities. We show that there are new phases of type I or heterotic string theory in six dimensions, involving extra tensor multiplets, which arise when small instantons sit on orbifold singularities. The theories with extra tensor multiplets are explicitly constructed via orientifolds. Th

  48. Mark Bowick, Marco Falcioni, Gudmar Thorleifsson

    We provide the first numerical evidence for the existence of a tubular phase, predicted by Radzihovsky and Toner (RT), for anisotropic tethered membranes without self-avoidance. Incorporating anisotropy into the bending rigidity of a simple model of a tethered membrane with free boundary conditions, we show that the model indeed has two phase transitions cor

  49. Jungsoo Kim, D. Coffey

    We review the leading momentum, frequency and temperature dependences of the single particle self-energy and the corresponding term in the entropy of a two dimensional Fermi liquid (FL) with a free particle spectrum. We calculate the corrections to these leading dependences for the paramagnon model and the electron gas and find that the leading dependences a

  50. Andrew Gould, Osamu Uza

    We remeasure the ``light echo&#39;&#39; times to the near and far side of the ring around SN 1987A using the method of Gould (1995) and the new reductions of the original UV spectra by Sonneborn et al. (1996). Under the assumption that the ring is circular, we obtain an upper limit to the distance to the Large Magellanic Cloud μ_lmc < 18.37 +/- 0.04. This re

  51. Igor Halperin, Ariel Zhitnitsky

    New mechanism for the observed inclusive B -> η&#39;X decay is suggested. We argue that the dominant contribution to this amplitude is due to the Cabbibo favored b -> \bar{c}cs process followed by the transition \bar{c}c -> η&#39;. A large magnitude of the &#34;intrinsic charm&#34; component of η&#39; is of critical importance in our approach. Our results ar

  52. Dieter R. Brill, Jorma Louko, Peter Peldan

    We examine counterparts of the Reissner-Nordstrom-anti-de Sitter black hole spacetimes in which the two-sphere has been replaced by a surface Sigma of constant negative or zero curvature. When horizons exist, the spacetimes are black holes with an asymptotically locally anti-de Sitter infinity, but the infinity topology differs from that in the asymptoticall

  53. David C. Butler

    Let SU(r,d) be the moduli space of rank r, degree d vector bundles over a smooth projective curve of genus $g\ge 2$. If (r,d)=1 and d divides r+1, then SU is rational. Furthermore, if $0<δ< r$ and all prime divisors of $δ$ divide r, and if d divides $r-δ$, then SU is rational. The proof is a variation on a result of Newstead and modifications due to Ballico

  54. L. Diosi, J. J. Halliwell

    We propose a system of equations to describe the interaction of a quasiclassical variable $X$ with a set of quantum variables $x$ that goes beyond the usual mean field approximation. The idea is to regard the quantum system as continuously and imprecisely measured by the classical system. The effective equations of motion for the classical system therefore c

  55. W. Cassing, E. L. Bratkovskaya

    We study the production of $c \bar{c}$ pairs and dimuons from hard collisions in nuclear reactions within the covariant transport approach HSD, which describes successfully both hadronic and electromagnetic observables from p+A and A+A collisions from SIS to SPS energies. The production of $c \bar{c}$ and Drell-Yan pairs is treated perturbatively employing e

  56. E. Bergshoeff, R. Kallosh, T. Ortin, G. Papadopoulos

    We present a new form of kappa-symmetry transformations for D-branes in which the dependence on the Born-Infeld field strength is expressed as a relative rotation on the left- and right-moving fields with opposite parameters. Then, we apply this result to investigate the supersymmetry preserved by certain intersecting brane configurations at arbitrary angles

  57. David Carter

    I describe the TreeBanker, a graphical tool for the supervised training involved in domain customization of the disambiguation component of a speech- or language-understanding system. The TreeBanker presents a user, who need not be a system expert, with a range of properties that distinguish competing analyses for an utterance and that are relatively easy to

  58. O. A. Borisenko, M. N. Chernodub, F. V. Gubarev

    We discuss a new approach to the investigation of the nature of the mass gap in spin systems with continuous global symmetries which is much analogous to the method of abelian projection in the gauge theories. We suggest that the abelian degrees of freedom, in particular, abelian vortices are responsible for the mass gap generation phenomena in the non-abeli

  59. D. K. Park, Sahng-Kyoon Yoo, Soo-Young Lee, Jae-Rok Kahng

    The propagator of three-dimensional Aharonov-Bohm-Coulomb system is calculated by following the Duru-Kleinert method. It is shown that the system is reduced to two independent two dimensional Aharonov-Bohm plus harmonic oscillator systems through dimensional extension and Kustaanheimo-Stiefel transformation. The energy spectrum is deduced.

  60. C. Wilke, T. Martinetz

    A simple model of biological extinction with variable system size is presented that exhibits a power-law distribution of extinction event sizes. The model is a generalization of a model recently introduced by Newman (Proc. R. Soc. Lond. B265, 1605 (1996). Both analytical and numerical analysis show that the exponent of the power-law distribution depends only

  61. E. Pignatelli, G. Galletta

    We present here a self-consistent, tridimensional model of a disc galaxy composed by a number of ellipsoidal distributions of matter having different flattening and density profile. The model is self-consistent and takes into account the observed luminosity distribution, the flattening profile and the stellar rotation- and velocity dispersion- curves. In thi

  62. M. Lagraa, N. Touhami

    From the bicovariant first order differential calculus on inhomogeneous Hopf algebra ${\cal B}$ we construct the set of right-invariant Maurer-Cartan one-forms considered as a right-invariant basis of a bicovariant ${\cal B}$-bimodule over which we develop the Woronowicz&#39;s general theory of differential calculus on quantum groups. In this formalism, we i

  63. E. S. Cheng, D. A. Cottingham, D. J. Fixsen, A. B. Goldin

    The third flight of the Medium Scale Anisotropy Measurement (MSAM1), in June 1995, observed a new strip of sky, doubling the sky coverage of the original MSAM1 dataset. MSAM1 observes with a 0.5 deg beam size in four bands from 5-20 icm. From these four bands we derive measurements of cosmic microwave background radiation (CMBR) anisotropy and interstellar d

  64. Keiko Miyahata, Satoru Ikeuchi

    (ABRIDGED)The Ly$α$ clouds at low redshifts (z < 1.7)observed by HST showed us two unexpected features: Lanzetta et.al.establised the association between Ly$α$ clouds and galaxies, and Ulmer pointed out the strong clustering of Ly$α$ clouds. Motivated by these observations together with another observation which reports the detection of metal in the Ly$α$ cl

  65. C. Glenn Boyd, Benjamin Grinstein, Richard F. Lebed

    We present precision corrections to dispersion relation bounds on form factors in bottom hadron semileptonic decays and analyze their effects on parameterizations derived from these bounds. We incorporate QCD two-loop and nonperturbative corrections to the two-point correlator, consider form factors whose contribution to decay rates is suppressed by lepton m

  66. L. A. Bordag, V. S. Dryuma

    The investigation of nonlinear dynamical systems of the type $\dot{x}=P(x,y,z),\dot{y}=Q(x,y,z),\dot{z}=R(x,y,z)$ by means of reduction to some ordinary differential equations of the second order in the form $y&#39;&#39;+a_1(x,y)y&#39;^3+3a_2(x,y)y&#39;^2+3a_3(x,y)y&#39;+a_4(x,y)=0$ is done. The main backbone of this investigation was provided by the theory

  67. A. Bohm, M. Loewe, S. Maxson, P. Patuleanu

    In analogy to Gamow vectors that are obtained from first order resonance poles of the S-matrix, one can also define higher order Gamow vectors which are derived from higher order poles of the S-matrix. An S-matrix pole of r-th order at z_R=E_R-iΓ/2 leads to r generalized eigenvectors of order k= 0, 1, ... , r-1, which are also Jordan vectors of degree (k+1)

  68. A. Bohm, M. Loewe, P. Patuleanu, C. Puntmann

    In the framework of the rigged Hilbert space, unstable quantum systems associated with first order poles of the analytically continued S-matrix can be described by Gamow vectors which are generalized vectors with exponential decay and a Breit-Wigner energy distribution. This mathematical formalism can be generalized to quasistationary systems associated with

  69. David P. DiVincenzo

    A historical review is given of the emergence of the idea of the quantum logic gate from the theory of reversible Boolean gates. I highlight the quantum XOR or controlled NOT as the fundamental two-bit gate for quantum computation. This gate plays a central role in networks for quantum error correction.

  70. Anders Karlsson, Gunnar Bjork, Erik Forsberg

    We analyse interaction-free measurements on classical and quantum objects. We show the transition from a classical interaction free measurement to a quantum non-demolition measurement of atom number, and discuss the mechanism of the enforcement of complementarity in atom interferometric interaction-free measurements.

  71. Stavros Garoufalidis, Tomotada Ohtsuki

    We introduce the notion of weight system for finite type invariants of integral homology 3-spheres, and we show that invariants of type m are determined, modulo invariants of type m-1, by their associated weight system.

  72. Royce Kam, Herbert Levine

    We present a model for unicellular algal growth as motivated by several experiments implicating the importance of calcium ions and ``loosening&#39;&#39; enzymes in morphogenesis. A growing cell at rest in a diffusive calcium solution is viewed as an elastic shell on short timescales. For a given turgor pressure, we calculate the stressed shapes of the wall e

  73. T. Kunihiro, J. Matsukidaira

    The renormalization group (RG) method is extended for global asymptotic analysis of discrete systems. We show that the RG equation in the discretized form leads to difference equations corresponding to the Stuart-Landau or Ginzburg-Landau equations. We propose a discretization scheme which leads to a faithful discretization of the reduced dynamics of the ori

  74. F. Antonuccio

    We discuss the issue of renormalization and the derivation of effective interactions for light-cone Hamiltonians in the context of large-N scalar matrix models with $Φ^3$ interactions. For various space-time dimensions $D \geq 3$, we deduce appropriate mass, coupling constant, and wavefunction renormalizations which are necessary for finiteness of the Hamilt

  75. Mikhail Plyushchay

    We show that deformed Heisenberg algebra with reflection emerging in parabosonic constructions is also related to parafermions. This universality is discussed in different algebraic aspects and is employed for the description of spin-j fields, anyons and supersymmetry in 2+1 dimensions.

  76. Arno Bohm

    The neutral Kaon system is used to test the quantum theory of resonance scattering and decay phenomena. The two dimensional Lee-Oehme-Yang theory with complex Hamiltonian is obtained by truncating the complex basis vector expansion of the exact theory in Rigged Hilbert space. This can be done for K_1 and K_2 as well as for K_S and K_L, depending upon whether

  77. Timothy J. Hollowood

    A first principles calculation of the quantum corrections to the electric charge of a dyon in an N=2 gauge theory with arbitrary gauge group is presented. These corrections arise from the fermion fields via the mechanism of fermion fractionalization. For a dyon whose magnetic charge is a non-simple co-root, the correction is a discontinuous function on the m

  78. J. B&#34;ockenhauer, J. Fuchs

    It is demonstrated that several series of conformal field theories, while satisfying braid group statistics, can still be described in the conventional setting of the DHR theory, i.e. their superselection structure can be understood in terms of a compact DHR gauge group. Besides theories with only simple sectors, these include (the untwisted part of) c=1 orb

  79. Jorgen Randrup, Robert L. Thews

    Wavelet-type methods are employed for the analysis of pion field configurations that have been obtained by dynamical simulations in idealized scenarios relevant to the formation of disoriented chiral condensates. It is illustrated how the measurement of the isospin domain structure depends on the ability to zoom in on limited parts of the phase space, due to

  80. E. G. Ferreiro, C. Pajares

    String Fusion Model Code results for Pb--Pb central collisions at SPS energies including the string fusion interaction mechanism are compared to the last experimental data. Predictions for RHIC energies are also presented. On the other hand, the evolution of the strangeness enhancement ratio $E_s=\frac{<Λ>+4<K_s^0>}{3<π^->}$ with the energy and with the atom

  81. A. D. Martin, M. G. Ryskin, V. A. Khoze

    We show that the hadroproduction of a pair of jets with large transverse energy in the central region bounded by rapidity gaps is an ideal process to see important double logarithmic QCD suppression effects. We compute the cross sections for both exclusive and inclusive double-diffractive dijet production at Tevatron and LHC energies for a range of rapidity

  82. V. A. Saleev

    In the framework of the nonrelativistic diquark model of the heavy baryons and the perturbative approach of QCD we predict the value and energy dependence for the total cross section of the Lambda_b- and Sigma_b^* -baryons pair production at the energy range of the KEKB and PEP-II e^+e^- colliders.

  83. Chaejun Song, G. E. Brown, Dong-Pil Min, Mannque Rho

    We develop arguments for &#34;mapping&#34; the effective chiral Lagrangian whose parameters are given by &#34;BR scaling&#34; to a Landau Fermi-liquid fixed-point theory for nuclear matter in describing fluctuations in various flavor (e.g., strangeness) directions. We use for this purpose the effective Lagrangian used by Furnstahl, Tang and Serot that incorp

  84. K. G. Chetyrkin, J. H. Kühn, M. Steinhauser

    In this paper the three-loop polarization functions Π(q^2) are calculated for the cases of an external vector, axial-vector, scalar or pseudo-scalar current. Results are presented for the imaginary part which directly leads to the cross section $σ(e^+e^- \to Z \to hadrons)$ and to the Higgs decay rates, respectively.

  85. G. Buchalla, G. Isidori, S. -J. Rey

    We calculate nonperturbative ${\cal O}(Λ^2_{QCD}/m^2_c)$ corrections to the dilepton invariant mass spectrum and the forward-backward charge asymmetry in $B\to X_se^+e^-$ decay using a heavy quark expansion approach. The method has recently been used to estimate long-distance effects in $B\to X_sγ$. We generalize this analysis to the case of nonvanishing pho

  86. Bernd A. Berg

    Recent progress of simulations with non-canonical weight factors is summarized.

  87. M. Dittmar, F. Pauss, D. Zuercher

    A new approach to determine the LHC luminosity is investigated. Instead of employing the proton-proton luminosity measurement, we suggest to measure directly the parton-parton luminosity. It is shown that the electron and muon pseudorapidity distributions, originating from the decay of W+, W- and Z0 bosons produced at 14 TeV pp collisions (LHC), constrain th

  88. N. M. Astafyeva, I. M. Dremin, K. A. Kotelnikov

    In very high energy collisions, many particles are produced and distributed in the available phase space volume in various ways. With advent of new accelerator facilities (especially, for nucleus-nucleus collisions), the problem of pattern recognition in high multiplicity events becomes very actual in order to classify such events and to separate those of th

  89. H. Zaidi, J. Gegenberg

    We propose a model for the geometry of a dynamical spherical shell in which the metric is asymptotically Schwarzschild, but deviates from Ricci-flatness in a finite neighbourhood of the shell. Hence, the geometry corresponds to a `hairy&#39; black hole, with the hair originating on the shell. The metric is regular for an infalling shell, but it bifurcates, l

  90. Andrzej Krasinski

    For a rotating dust with a 3-dimensional symmetry group all possible metric forms can be classified and, within each class, explicitly written out. This is made possible by the formalism of Plebański based on the Darboux theorem. In the resulting coordinates, the Killing vector fields (if any exist) assume a special form. Each Killing vector field may be eit

  91. Amina Helmi, Hector Vucetich

    A brief analysis of the dynamics of a Friedmann-Robertson-Walker universe with a conformally coupled, real, self-interacting, massive scalar field, based on the Painleve theory of differential equations, is presented. Our results complete earlier works done within the framework of Dynamical System Theory. We conclude that, in general, the system will not be

  92. P. R. Broussard, S. B. Qadri, V. C. Cestone

    We have performed x-ray photoemission spectroscopy (XPS) on thin films of (001) and (200) oriented La(0.67)Ca(0.33)MnO(3) grown on (100) and (110) SrTiO(3) substrates by off-axis sputtering. The films were examined by XPS without exposing them to air. We have compared the core levels and the valence spectra between the two different orientations, as well as

  93. Janez Bonca, S. A. Trugman

    We solve a Schrodinger equation for inelastic quantum transport that retains full quantum coherence, in contrast to previous rate or Boltzmann equation approaches. The model Hamiltonian is the zero temperature 1d Holstein model for an electron coupled to optical phonons (polaron), in a strong electric field. The Hilbert space grows exponentially with electro

  94. L. Angelini, M. Pellicoro, I. Sardella, M. Villani

    The ferromagnetic q-state Potts model on a square lattice is analyzed, for q>4, through an elaborate version of the operatorial variational method. In the variational approach proposed in the paper, the duality relations are exactly satisfied, involving at a more fundamental level, a duality relationship between variational parameters. Besides some exact pre

  95. M. A. Teplov, Yu. A. Sakhratov, A. V. Dooglav, A. V. Egorov

    Pulsed NQR at the frequencies of 28-33 MHz has been used to study copper NQR spectra in YBa{2}Cu{3}O{7}, TmBa{2}Cu{3}O{7} and Y{0.9}Pr{0.1}Ba{2}Cu{3}O{7} compounds at temperatures of 4.2-200K. Quantitative analysis of the spectra has shown that the &#34;plane&#34; Cu(2) spectra shape is well described by using a model of 1D correlations of charge and spin di

  96. D. J. Singh, I. I. Mazin

    The thermoelectric properties of La-filled skutterudites are discussed from the point of view of their electronic structures. These are calculated from first principles within the local density approximation. The electronic structure is in turn used to determine transport related quantities. Virtual crystal calculations for La(Fe,Co)_4Sb_{12} show that the s

  97. Valentina S. U. Fazio

    The RCSJ (Resistor-Capacitor Shunted Junction) model provides us an analytical formula for the conversion efficiency for a resonant Josephson effect mixer. An external rf signal is applied to a long Josephson junction operating in the fluxon oscillating regime. The sine-Gordon equation is used to investigate the dynamics of the phase-locking between the flux

  98. A. Ferraz, S. L. Garavelli, T. Saikawa

    We consider a local effective model for fermionic low lying excitations in a metal. Introducing a boson auxiliary field and taking into account that the most significant interactions between quasiparticles arise for those which are near a given point on the Fermi surface, we find that the effective boson-fermion interaction is singular for a spatial dimensio

  99. Bodo Huckestein, Rochus Klesse

    We review the time evolution of wavepackets at the metal-insulator transition in two- and three-dimensional disordered systems. The importance of scale invariance and multifractal eigenfunction fluctuations is stressed. The implications of the frequency- and wavevector-dependence of the diffusion coefficient are compared with the results of numerical simulat

  100. S. Zimmermann, A. O. Govorov, W. Hansen, J. P. Kotthaus

    We demonstrate the localisation of quantum well excitons in a periodic array of linear traps using photoluminescence experiments. The excitonic traps are induced by applying spatially alternating external voltages via interdigitated metal gates. The localisation originates from the periodical modulation of the strength of the quantum-confined Stark effect in