January 1998 arXiv papers — page 10

Dan Radu Grigore

We present here a possible generalisation of the Poincaré-Cartan form in classical field theory in the most general case: arbitrary dimension, arbitrary order of the theory and in the absence of a fibre bundle structure. We use for the kinematical description of the system the $(r,n)$-Grassmann manifold associated to a given manifold $X$, i.e. the manifold o

Shamit Kachru

We describe some of the novel 6d quantum field theories which have been discovered in studies of string duality. The role these theories (and their 4d descendants) may play in alleviating the vacuum degeneracy problem in string theory is reviewed. The DLCQ of these field theories is presented as one concrete way of formulating them, independent of string the

G. W. Gibbons

I describe some recent work in which classical solutions of Dirac-Born-Infeld theory may be used to throw light on some properties of M-theory. The sources of Born-Infeld theory are the ends of strings ending on the world volume. Equivalently the fundamental string may be regarded as merely a thin and extended piece of the world volume.

Fiorenzo Bastianelli, Koenraad Schalm, Peter van Nieuwenhuizen

A simple, often invoked, regularization scheme of quantum mechanical path integrals in curved space is mode regularization: one expands fields into a Fourier series, performs calculations with only the first $M$ modes, and at the end takes the limit $M \to \infty$. This simple scheme does not manifestly preserve reparametrization invariance of the target man

S. Penati, A. Refolli, A. Van Proeyen, D. Zanon

We consider N=2 supersymmetric nonlinear sigma-models in two dimensions defined in terms of the nonminimal scalar multiplet. We compute in superspace the one-loop beta function and show that the classical duality between these models and the standard ones defined in terms of chiral superfields is maintained at the quantum one-loop level. Our result provides

Carlo Becchi, Stefano Giusto, Camillo Imbimbo

We show that the BRS operator of the topological string B model is not holomorphic in the complex structure of the target space. This implies that the so-called holomorphic anomaly of topological strings should not be interpreted as a BRS anomaly.

J. Ambjorn, D. Boulatov, J. L. Nielsen, J. Rolf

We show that the spectral dimension d_s of two-dimensional quantum gravity coupled to Gaussian fields is two for all values of the central charge c <= 1. The same arguments provide a simple proof of the known result d_s= 4/3 for branched polymers.

C. R. Gattringer, S. Jaimungal, G. W. Semenoff

Starting from the known representation of the partition function of the 2- and 3-D Ising models as an integral over Grassmann variables, we perform a hopping expansion of the corresponding Pfaffian. We show that this expansion is an exact, algebraic representation of the loop- and surface expansions (with intrinsic geometry) of the 2- and 3-D Ising models. S

S. D. H. Hsu, F. Sannino, J. Schechter

We explore the anomaly induced effective QCD meson potential in the framework of the effective Lagrangian approach. We suggest a decoupling procedure, when a flavored quark becomes massive, which mimics the one employed by Seiberg for supersymmetric gauge theories. It is seen that, after decoupling, the QCD potential naturally converts to the one with one le

Thomas D. Cohen

Exotic mesons with quantum numbers of a hybrid ($\bar{q} q g$) such as $J^{PC} = 1^{-+}$are shown to exist as narrow resonant states in the large $N_c$ limit of QCD. The width of these states is proportional to $1/N_c$. Possible phenomenological implications for the world of $N_c=3$ are discussed.

Dan-Di Wu

Rephasing invariant formalism for the $K^0-\bar K^0$ system is recommended for the Particle Data Group. This formalism is accurate and prevents possible errors in generalizing the formalism to other systems, as well as in using CKM matrices not included in the Particle Data Book.

I. N. Mishustin, J. A. Pedersen, O. Scavenius

We investigate the dynamics of the chiral transition in an expanding quark-anti-quark plasma. The calculations are made within a linear sigma model with explicit quark and antiquark degrees of freedom. We solve numerically the classical equations of motion for chiral fields coupled to the fluid dynamical equations for the plasma. Fast initial growth and stro

N. Rius

We discuss the (non)-restoration of global and local symmetries at high temperature. First, we analyze a two-scalar model with $Z_2 \times Z_2$ symmetry using the exact renormalization group. We conclude that inverse symmetry breaking is possible in this kind of models within the perturbative regime. Regarding local symmetries, we consider the $SU(2) \otimes

O. J. P. Eboli, R. Z. Funchal, T. L. Lungov

We review the present seach for scalar leptoquarks and the potential of the CERN Large Hadron Collider (LHC) to unravel the existence of first generation leptoquarks. Talk given by O. J. P. Eboli at the International Workshop on &#34;Physics Beyond the Standard Model: from Theory to Experiment&#34;, Valencia, 1997.

A. Lindner

Recent highlight results obtained with the air shower detector complex HEGRA at the Canary island La Palma are presented. Observations and searches for gamma sources above an energy of 500 GeV are covered, where special emphasis is put on the recent flaring activities of the Blazar Mkn 501. A second main research topic of the experiment is the measurement of

V. Vento

The concept of effective field theory leads in a natural way to a construction principle for phenomenological sensible models known under the name of the Cheshire Cat Principle. We review its formulation in the chiral bag scenario and discuss its realization for the flavor singlet axial charge. Quantum effects inside the chiral bag induce a color anomaly whi

J. Y. Cui, H. Y. Jin, J. M. Wu

We construct the B.S. equation for baryons. The most general form of the B.S. wave function is given. In the heavy quark limit we show clearly that the spin symmetry exists in heavy baryon states.

Michael Grady

The effect of restricting the plaquette ($1\times 1$ Wilson loop) to be greater than a certain cutoff is studied. The action considered is the standard Wilson action with the addition of the plaquette restriction, which does not affect the continuum limit. A deconfining phase transition occurs as the cutoff is raised, even in the strong coupling limit. Abeli

F. Abe

We present a measurement of the top quark mass using a sample of t-tbar decays into an electron or a muon, a neutrino, and four jets. The data were collected in p-pbar collisions at sqrt(s)=1.8 TeV with the Collider Detector at Fermilab and correspond to an integrated luminosity of 109 pb^-1. We measure the top quark mass to be 175.9 +/- 4.8(stat.) +/- 4.9(s

A. Katrin Schenk, Stuart L. Shapiro, Saul A. Teukolsky

We present a method for constructing equilibrium disks with net angular momentum in general relativity. The method solves the relativistic Vlasov equation coupled to Einstein&#39;s equations for the gravitational field. We apply the method to construct disks that are relativistic versions of Newtonian Kalnajs disks. In Newtonian gravity these disks are analy

R. Gambini, O. Obregon, J. Pullin

We draw parallels between the recently introduced ``Immirzi ambiguity&#39;&#39; of the Ashtekar-like formulation of canonical quantum gravity and other ambiguities that appear in Yang-Mills theories, like the $θ$ ambiguity. We also discuss ambiguities in the Maxwell case, and implication for the loop quantization of these theories.

J. Podolsky, K. Vesely

Non-standard sandwich gravitational waves are constructed from the homogeneous pp vacuum solution and the motions of free test particles in the space-times are calculated explicitly. They demonstrate the caustic property of sandwich waves. By performing limits to impulsive gravitational wave it is demonstrated that the resulting particle motions are identica

T. Ledvinka, M. Zofka, J. Bicak

If an appropriate region of Kerr-Newman space-time is removed and suitable identifications are made, the resulting space-time can be interpreted as an infinitely thin disk producing the original electromagnetic and gravitational fields. We choose the shape of the regions removed in such a way that radial pressures in the disks vanish. Even the very inner par

J. Podolsky

The Siklos class of solutions of Einstein&#39;s field equations is investigated by analytical methods. By studying the behaviour of free particles we reach the conclusion that the space-times represent exact gravitational waves propagating in the anti-de Sitter universe. The presence of a negative cosmological constant implies that the &#39;background&#39; s

S. Antoci

The relation between microscopic and macroscopic entities in the generally covariant theories is considered, and it is argued that a sensible definition of the macroscopic averages requires a restriction of the allowed transformations of coordinates. Spacetime averages of the geometric objects of Einstein&#39;s unified field theory are then defined, and the

Donald E. Knuth

Mallows and Riordan showed in 1968 that labeled trees with a small number of inversions are related to labeled graphs that are connected and sparse. Wright enumerated sparse connected graphs in 1977, and Kreweras related the inversions of trees to the so-called ``parking problem&#39;&#39; in 1980. A~combination of these three results leads to a surprisingly

V. I. Raisanen, E. T. Seppala, M. J. Alava, P. M. Duxbury

We compare the roughness of minimal energy(ME) surfaces and scalar ``quasi-static&#39;&#39; fracture surfaces(SQF). Two dimensional ME and SQF surfaces have the same roughness scaling, w sim L^zeta (L is system size) with zeta = 2/3. The 3-d ME and SQF results at strong disorder are consistent with the random-bond Ising exponent zeta (d >= 3) approx 0.21(5-d

Subhasis Sinha

We calculate the quantum corrections of the thermodynamic quantities of a system of confined Bosons at finite temperature. Systematically quantum corrections are written in a series of $\hbar$, which is convergent when $kT$ is much larger than the spacing between energy levels of the system. We apply this method to calculate analytically the thermodynamic po

Garnett W. Bryant, Eric L. Shirley, Lori S. Goldner, Eric B. McDaniel

While near-field scanning optical microscopy (NSOM) can provide optical images with resolution much better than the diffraction limit, analysis and interpretation of these images is often difficult. We present a theory of imaging with transmission NSOM that includes the effects of tip field, tip/sample coupling, light propagation through the sample and light

N. R. Cooper

A branch of uniformly-propagating solitary waves of planar ferromagnets is identified. The energy dispersion and structures of the solitary waves are determined for an isotropic ferromagnet as functions of a conserved momentum. With increasing momentum, their structure undergoes a transition from a form ressembling a droplet of spin-waves to a Skyrmion/anti-

A. S. Chen, Yu. M. Bunkov, H. Godfrin, R. Schanen

Due to its broken spin and orbit rotation symmetries, superfluid $^3$He plays a unique role for testing rotational quantum properties on a macroscopic scale. In this system the orbital momentum forms textures that provide an effective potential well for the creation of stationary spin waves. In the limit of the lowest temperatures presently attainable, we ob

N. Andrei, P. Zinn-Justin

The SU(N) generalization of the multi-channel Kondo model with arbitrary rectangular impurity representations is considered by means of the Bethe Ansatz. The thermodynamics of the model is analyzed by introducing modified fusion equations for the impurity, leading to a simple description of the different IR fixed points of the theory. The entropy at zero tem

E. Louis, F. Guinea, M. P. Lopez Sancho, J. A. Verges

The interactions between holes in the Hubbard model, in the low density, intermediate to strong coupling limit, are investigated. Dressed spin polarons in neighboring sites have an increased kinetic energy and an enhanced hopping rate. Both effects are of the order of the hopping integral and lead to an effective attraction at intermediate couplings. Our res

Alexander Zyuzin

We consider the cooperative decay of incoherently pumped atoms in a disordered medium, where light undergoes multiple scattering. It is shown that the cooperation number, which determines the duration and amplitude of superfluorescent impulses, is given by the number of atoms along a diffusive trajectory of the light propagating through the medium. We also c

Miguel Cardenas, Silvio Franz, Giorgio Parisi

By means of an effective potential associated to a constrained equilibrium measure and apt to study frozen systems, we investigate glassy freezing in simple liquids in the hypernetted chain (HNC) approximation. Differently from other classical approximations of liquid theory, freezing is naturally embedded in the HNC approximation. We get a detailed descript

A. Toelle, H. Schober, J. Wuttke, F. Fujara

The incoherent dynamic structure factor of ortho-terphenyl has been measured by neutron time-of-flight and backscattering technique in the pressure range from 0.1 MPa to 240 MPa for temperatures between 301 K and 335 K. Tagged-particle correlations in the compressed liquid decay in two steps. The alpha-relaxation lineshape is independent of pressure, and the

Tsuyoshi Hondou

Studies of noise-induced motions are showing that coherent energy can be extracted from some kinds of noise in a periodic ratchet. Recently, energetics of Langevin dynamics is formulated by Sekimoto [J.Phys.Soc.Jpn, 66 1234 (1997)], which can be applied to ratchet systems described by Fokker-Planck equation. In this paper, we derive an energetics of ratchet

Yong-Jihn Kim

We review the recent progress in the theory of inhomogeneous superconductors. It was shown that Gor&#39;kov&#39;s self-consistency equation needs a pairing constraint derived from the Anomalous Green&#39;s function. The Bogoliubov-de Gennes equations also need a pairing constraint in order to obtain a correct vacuum state by the corresponding unitary transfo

R. J. Baxter

As a by-product of a finite-size Bethe Ansatz calculation in statistical mechanics, Doochul Kim has established, by an indirect route, three mathematical identities rather similar to the conjugate modulus relations satisfied by the elliptic theta constants. However, they contain factors like $1 - q^{\sqrt{n}}$ and $1 - q^{n^2}$, instead of $1 - q^n$. We show

Ramakrishna Ramaswamy, Sudeshna Sinha, Neelima Gupte

We describe adaptive control algorithms whereby a chaotic dynamical system can be steered to a target state with desired characteristics. A specific implementation considered has the objective of directing the system to a state which is more chaotic or mixed than the uncontrolled one. This methodology is easy to implement in discrete or continuous dynamical

D. Matrasulov

Stochastic ionization of highly excited relativistic hydrogenlike atom in the monochromatic field is considered. A theoretical analisis of chaotic dynamics of the electron based on Chirikov&#39;s criterion is given. Critical value of the external field is evaluated analytically.

Awadhesh Prasad, Ramakrishna Ramaswamy

The probability distribution of finite-time Lyapunov exponents provides an important characterization of dynamical attractors. We study such distributions for strange nonchaotic attractors (SNAs) created through several different mechanisms in quasiperiodically forced nonlinear dynamical systems. Statistical properties of the distributions such as the varian

A. N. Taylor, S. Dye, T. J. Broadhurst, N. Benitez

We present the first application of lens magnification to measure the absolute mass of a galaxy cluster; Abell 1689. The absolute mass of a galaxy cluster can be measured by the gravitational lens magnification of a background galaxy population by the cluster potential. The lensing signal is complicated by the variation in number counts due to galaxy cluster

C. L. Carilli, K. M. Menten, M. J. Reid, M. Rupen

We present spectroscopic imaging observations of the molecular and HI 21cm absorbing cloud at z = 0.885 toward the `Einstein ring&#39; radio source PKS 1830-211. We derive a cloud size between 10 h^{-1} pc and 600 h^{-1} pc, and M(H_2) > 2.6x10^{4} h^{-2} Msolar. The temperature of the ambient radiation field is 4.5+/-0.9 K, consistent with the microwave bac

P. F. Bloser, T. Narita, J. E. Grindlay, K. Shah

We describe initial results of our program to develop and test Cd-Zn-Te (CZT) detectors with a pixellated array readout. Our primary interest is in the development of relatively thick CZT detectors for use in astrophysical coded aperture telescopes with response extending over the energy range $\sim 10-600$ keV. The coded aperture imaging configuration requi

Timothy M. Heckman

Starbursts are important because they can serve as local analogs of the processes that were important in the origin and early evolution of galaxies and in the heating and chemical enrichment of the inter-galactic medium. They may also play an important role in the AGN phenomenon. In this contribution I review the use of UV spectroscopic diagnostics that can

Matt Burleigh, Martin Barstow

We report the discovery, in an Extreme Ultraviolet Explorer (EUVE) short wavelength spectrum, of an unresolved hot white dwarf companion to the 5th-magnitude B5Vp star HR2875. This is the first time that a non-interacting white dwarf$+$ B star binary has been discovered; previously, the the earliest type star known with a white dwarf companion was Sirius (A1

Stephen Eales

The large number of differences between high- and low-redshift radio galaxies have almost all been discovered by looking at the bright 3C sample of radio sources. This has the disadvantage that the strong correlation between radio luminosity and redshift within a single sample makes it impossible to be determine whether these differences are the result of co

F. Sylos Labini, M. Montuori, L. Pietronero

This comment is in response to the paper by L. Guzzo recently appeared in ``New Astronomy&#39;&#39; related to our work. The subject of the discussion concerns the correlation properties of galaxy distribution in the available 3-d samples. There is a general agreement that galaxy structures exhibit fractal properties, at least up to some scale. However the p

I. Ferreras, N. Benitez, E. Martinez-Gonzalez

We present a list of candidates for high redshift late-type galaxies in the field around the z=3.79 quasar PC1643+4631A. Deep U,V and R imaging has been used to search for objects with a strong Lyman break between U and V, characteristic of galaxies with high hydrogen column densities at $z\sim 3$. A further study of the red objects detected by Hu & Ridgway

Ian Waddington

At z=2.39, the cluster around 53W002 is one of the most distant groups or clusters of galaxies known to date. At this redshift the 4000A-break falls between the J and H bands, thus our infrared observations are designed to identify cluster members by a red J-H colour. Out of the 42 objects we have detected in the field, we find ten galaxies with J-H>1.0 and

Andrew R Liddle

I give a status report and outlook concerning the use of the cosmic microwave background anisotropies to constrain the inflationary cosmology, and stress its crucial role as an underlying paradigm for the estimation of cosmological parameters.

A. Lindner

A Monte-Carlo study to reconstruct energy and mass of cosmic rays with energies above 300 TeV using ground based measurements of the electromagnetic part of showers initiated in the atmosphere is presented. The shower properties determined with two detector arrays measuring the air Cherenkov light and the particle densities as realized at the HEGRA experimen

Patrick Boisse, Vincent Le Brun, Jacqueline Bergeron, Jean-Michel Deharveng

We present HST spectra for a sample of six QSOs with intermediate redshift (z_a < 1) damped Ly-alpha systems. These observations aim at measuring the HI column density and detect metal lines in order to investigate the metal enrichment of the gas, as well as the presence of neutral species, molecules and dust. All systems selected on the basis of 21 cm absor

P. Maltby, N. Brynildsen, P. Brekke, S. V. H. Haugan

Bright EUV sunspot plumes have been observed in five out of nine sunspot regions with the Coronal Diagnostic Spectrometer -- CDS on SOHO. In the other four regions the brightest line emissions may appear inside the sunspot but are mainly concentrated in small regions outside the sunspot areas. These results are in contrast to those obtained during the Solar

Alister W. Graham

The influence of broken structural homology, and the implied broken dynamical homology, is examined for the Fundamental Plane (FP). A bisector method of linear regression was applied, in 3-dimensions, to derive the best FP and a bootstrapping procedure has been used to estimate the associated uncertainties. For 25 E and S0 Virgo galaxies, the `standard&#39;

Ting-Gui Wang, You-Jun Lu, You-Yuan Zhou

Anisotropic emission of the ionizing continuum is a general prediction of the accretion disk models. In this paper, we present the results of correlation analysis of the UV emission line and UV to X-ray continuum properties for a large sample of broad emission line AGNs observed with ROSAT, IUE and HST. We find strong correlations between the CIV/$Lyα$ ratio

David W. Hogg, Judith G. Cohen, Roger Blandford, Stephen D. J. Gwyn

Results of a blind test of photometric redshift predictions against spectroscopic galaxy redshifts obtained in the Hubble Deep Field with the Keck Telescope are presented. The best photometric redshift schemes predict spectroscopic redshifts with a redshift accuracy of |Delta-z|<0.1 for more than 68 percent of sources and with |Delta-z|<0.3 for 100 percent,

David Kaiser

The decay of disoriented chiral condensates into soft pions is considered within the context of a linear sigma model. Unlike earlier analytic studies, which focused on the production of pions as the sigma field rolled down toward its new equilibrium value, here we focus on the amplification of long-wavelength pion modes due to parametric resonance as the sig

Norm Murray, Brad Hansen, Matt Holman, Scott Tremaine

A planet orbiting in a disk of planetesimals can experience an instability in which it migrates to smaller orbital radii. Resonant interactions between the planet and planetesimals remove angular momentum from the planetesimals, increasing their eccentricities. Subsequently, the planetesimals either collide with or are ejected by the planet, reducing the sem

Lynne H. Orr, W. J. Stirling

The dependence of the subprocess cross section for dijet production at fixed transverse momentum on the (large) rapidity separation Delta y of the dijets can be used to test for `BFKL physics&#39;, i.e. the presence of higher--order (alphas log(Delta y)^n contributions. Unfortunately in practice these subtle effects are masked by the additional, stronger dep

E. W. Kolb, A. Riotto, I. I. Tkachev

We perform a fully non-linear calculation of the production of supermassive Grand Unified Theory (GUT) $X$ bosons during preheating, taking into account the fact that they are unstable with a decay width $Γ_X$. We show that parametric resonance does not develop if $Γ_X$ is larger than about $10^{-2} m_X$. We compute the nonthermal number density of superheav

M. A. Baranov

We reveal a strong influence of a superfluid phase transition on the character of single-particle excitations of a trapped neutral-atom Fermi gas. Below the transition temperature the presence of a spatially inhomogeneous order parameter (gap) shifts up the excitation eigenenergies and leads to the appearance of in-gap excitations localized in the outer part

A. Puglisi, V. Loreto, U. Marini Bettolo Marconi, A. Petri

We investigate the properties of a model of granular matter consisting of $N$ Brownian particles on a line subject to inelastic mutual collisions. This model displays a genuine thermodynamic limit for the mean values of the energy and the energy dissipation. When the typical relaxation time $τ$ associated with the Brownian process is small compared with the

Nora Menyhard, Geza Odor

Compact directed percolation is known to appear at the endpoint of the directed percolation critical line of the Domany-Kinzel cellular automaton in 1+1 dimension. Equivalently, such transition occurs at zero temperature in a magnetic field H, upon changing the sign of H, in the one-dimensional Glauber-Ising model with well known exponents characterising spi

A. De Roeck, A. Deshpande, V. W. Hughes, J. Lichtenstadt

We present estimates of possible data on spin-dependent asymmetries in inclusive scattering of high energy polarized electrons by high energy polarized protons at HERA with their statistical errors and discuss systematic errors. We show that these data will provide important information on the low-x behavior of the polarized structure function g_1, and will

Jort van Mourik, Cecilia Clementi, Amos Maritan, Flavio Seno

We propose a novel method for the determination of the effective interaction potential between the amino acids of a protein. The strategy is based on the combination of a new optimization procedure and a geometrical argument, which also uncovers the shortcomings of any optimization procedure. The strategy can be applied on any data set of native structures s

Tomohiro Harada

We investigate neutron stars in scalar-tensor theories. We examine their secular stability against spherically symmetric perturbations by use of a turning point method. For some choices of the coupling function contained in the theories, the number of the stable equilibrium solutions changes and the realized equilibrium may change discontinuously as the asym

G. Chanfray, J. Delorme, M. Ericson

We derive the expressions of the vector and axial current from a chiral Lagrangian restricted to nucleons and pions. They display mixing terms between the axial and vector currents. We study the modifications in the nuclear medium of the coupling constants of the axial current, namely the pion decay constant and the nucleonic axial one due to the requirement

D. Gomez Dumm, A. Pich

The dispersive two-photon contribution to the K_L --> mu+ mu- decay amplitude is analyzed, using chiral perturbation theory techniques and large-N_C considerations. A consistent description of the decays Pi^0 --> e+ e-, Eta --> mu+ mu- and K_L --> mu+ mu- is obtained. As a byproduct, one predicts Br(Eta --> e+ e-) = (5.8+-0.2) x 10^-9 and Br(K_L --> e+ e-) =

Véronique Bernard, Harold W. Fearing, Thomas R. Hemmert, Ulf-G. Meißner

We study the low energy expansion of the nucleon&#39;s electroweak form factors in the framework of an effective chiral Lagrangian including pions, nucleons and the $Delta (1232)$. We work to third order in the so-called small scale expansion and compare the results with the ones previously obtained in the chiral expansion. In addition, these calculations se

Xavier Waintal, Dietmar Weinmann, Jean-Louis Pichard

For two particles in a disordered chain of length $L$ with on-site interaction $U$, a duality transformation maps the behavior at weak interaction onto the behavior at strong interaction. Around the fixed point of this transformation, the interaction yields a maximum mixing of the one body states. When $L \approx L_1$ (the one particle localization length),

Hyun-Chul Kim, Michal Praszałowicz, Maxim V. Polyakov, Klaus Goeke

We use the chiral quark-soliton model to identify all symmetry breaking terms linear in $m_{s}$ and investigate the strange magnetic moment in a ``model-independent&#39;&#39; way. Assuming hedgehog symmetry and employing the collective quantization, we obtain the most general expression for the flavor-singlet and flavor-octet magnetic moments in terms of sev

Roger Bielawski

We compute the asymptotic metrics for moduli spaces of SU(N) monopoles with maximal symmetry breaking. These metrics are exponentially close to the exact monopole metric as soon as, for each simple root, the individual monopoles corresponding to that root are well separated. We also show that the estimates can be differentiated term by term in natural coordi

J. A. Jones, M. Mosca

We demonstrate the use of an NMR quantum computer based on the pyrimidine base cytosine, and the implementation of a quantum algorithm to solve Deutsch&#39;s problem.

Hermann Nicolai

This contribution gives a personal view on recent attempts to find a unified framework for non-perturbative string theories, with special emphasis on the hidden symmetries of supergravity and their possible role in this endeavor. A reformulation of $d=11$ supergravity with enlarged tangent space symmetry SO(1,2) $\times$ SO(16) is discussed from this perspec

M. Chaves, H. Morales

A generalization of the Yang-Mills covariant derivative, that uses both vector and scalar fields and transforms as a 4-vector contracted with Dirac matrices, is used to simplify and unify the Glashow-Weinberg-Salam model. Since SU(3) assigns the wrong hypercharge to the Higgs boson, it is necessary to use a special representation of U(3) to obtain all the co

Andre Lukas, Burt Ovrut, Daniel Waldram

We derive the ten-dimensional effective action of the strongly coupled heterotic string as the low energy limit of M-theory on S^1/Z_2. In contrast to a conventional dimensional reduction, it is necessary to integrate out nontrivial heavy modes which arise from the sources located on the orbifold fixed hyperplanes. This procedure, characteristic of theories

Krzysztof Kowalski

It is demonstrated that nonlinear dynamical systems with analytic nonlinearities can be brought down to the abstract Schrödinger equation in Hilbert space with boson Hamiltonian. The Fourier coefficients of the expansion of solutions to the Schrödinger equation in the particular occupation number representation are expressed by means of the classical orthogo

V. S. Shchesnovich, E. V. Doktorov

The perturbation theory based on the Riemann-Hilbert problem is developed for the modified nonlinear Schr{ö}dinger equation which describes the propagation of femtosecond optical pulses in nonlinear single-mode optical fibers. A detailed analysis of the adiabatic approximation to perturbation-induced evolution of the soliton parameters is given. The linear p

K. Kowalski, J. Rembielinski, L. C. Papaloucas

The coherent states for the quantum particle on the circle are introduced. The Bargmann representation within the actual treatment provides the representation of the algebra $[\hat J,U]=U$, where $U$ is unitary, which is a direct consequence of the Heisenberg algebra $[\hat ϕ, \hat J]=i$, but it is more adequate for the study of the circlular motion.

T. Kiss, U. Herzog, U. Leonhardt

The authors of the Comment [G. M. D&#39;Ariano and C. Macchiavello to be published in Phys. Rev. A, quant-ph/9701009] tried to reestablish a 0.5 efficiency bound for loss compensation in optical homodyne tomography. In our reply we demonstrate that neither does such a rigorous bound exist nor is the bound required for ruling out the state reconstruction of a

Atushi Tanaka

As examples of quantum-&#34;classical&#34; coupling systems, multi-component systems are studied by semiclassical evaluations of the Feynman kernels in the coherent-state representation. From the observation of the phase space caustics due to the presence of the internal degree of freedom (IDF), two phenomena are explained in terms of the semiclassical theor

Antoine Suarez

Relativistic Nonlocality is applied to experiments in which one of the photons impacts successively at two beam-splitters. It is discussed whether a time series with 2 non-before impacts can be produced with beam-splitters at rest, and such an experiment may allow us to decide between Quantum Mechanics (QM) and Relativistic Nonlocality (RNL).

Alexander A. Vlasov

In classical electrodynamics for rotating with variable angular velocity charged rigid sphere are found: the exact values of electromagnetic fields, the flux of radiating energy and the exact integral equation of rotation including the terms of self-rotation. The analysis of this eq. shows that on one hand, there is no &#34;runaway&#34; solutions, peculiar t

Jean-Louis Ballot, Manoel R. Robilotta, Carlos A. da Rocha

We assume that the nuclear potential for distances larger than 2.5 fm is given just by the exchanges of one and two pions and, for the latter, we adopt a model based on chiral symmetry and subthreshold pion-nucleon amplitudes, which contains no free parameters. The predictions produced by this model for nucleon-nucleon observables are calculated and shown to

Ernest M. Henley

Examples are given of the usefulness of electrons in interaction with nuclei for probing fundamental interactions and structure

Colin Adams, Joel Hass, Peter Scott

This paper determines which orientable hyperbolic 3-manifolds contain simple closed geodesics. The Fuchsian group corresponding to the thrice-punctured sphere generates the only example of a complete non-elementary orientable hyperbolic 3-manifold that does not contain a simple closed geodesic. We do not assume that the manifold is geometrically finite or th

Izumi Tsutsui, Masaomi Kimura, Hiroyuki Kobayashi

We re-examine three issues, the Hopf term, fractional spin and the soliton operators, in the 2+1 dimensional O(3) nonlinear sigma model based on the adjoint orbit parameterization (AOP) introduced earlier. It is shown that the Hopf Term is well-defined for configurations of any soliton charge $Q$ if we adopt a time independent boundary condition at spatial i

S. Ferrara

We report on duality invariant constraints, which allow a classification of BPS black holes preserving different fractions of supersymmetry. We then relate this analysis to the orbits of the exceptional groups $E_{6(6)}, E_{7(7)}$, relevant for black holes in five and four dimensions.

M. Gattobigio, A. Liguori, M. Mintchev

We establish the second quantized solution of the nonlinear Schrodinger equation on the half line with a mixed boundary condition. The solution is based on a new algebraic structure, which we call boundary exchange algebra and which substitutes, in the presence of boundaries, the familiar Zamolodchikov-Faddeev algebra.

Jan Plefka, Andrew Waldron

We study the Matrix theory from a purely canonical viewpoint. In particular, we identify free particle asymptotic states of the model corresponding to the 11D supergraviton multiplet along with the split of the matrix model Hamiltonian into a free and an interacting part. Elementary quantum mechanical perturbation theory then yields an effective potential fo

Roger Bielawski

We show that, in the region where monopoles are well separated, the L^2-metric on the moduli space of n-monopoles is exponentially close to the T^n-invariant hyperkähler metric proposed by Gibbons and Manton. The proof is based on a description of the Gibbons-Manton metric as a metric on a certain moduli space of solutions to Nahm&#39;s equations, and on twi

F. Lesage, H. Saleur

Boundary conditions changing operators have played an important role in conformal field theory. Here, we study their equivalent in the case where a mass scale is introduced, in an integrable way, either in the bulk or at the boundary. More precisely, we propose an axiomatic approach to determine the general scalar products ${}_b<θ_1, ... ,θ_m||θ&#39;_1, ...

Francisco Guerrero

From the properties of analyticity and unitarity it has been recently obtained an exponentiated expression for the pion form factor. In this work I show the validity of this expression comparing its order p^6 term with the one exactly calculated in ChPT.

Karim Benakli

We discuss the possible generation of R-parity violating bilinear terms $ μ_i\bar L_i H_2$ in both cases of gravity and gauge mediated supersymmetry breaking. Some phenomenological aspects are reviewed. In particular for scenario where $ μ_i$ depend on the vacuum expectation values of some fields $S$, its fermionic partner $\tilde S$ plays the role of a ster

R. Fiore, A. Flachi, L. L. Jenkovszky, F. Paccanoni

Pomeron non factorization for the diffractive scattering is considered and an analysis of experimental data is performed with different cuts in the momentum fraction $ξ$. The results of the analysis are compared with the breaking predicted in the Genovese-Nikolaev-Zakharov model.

T. Paul, Z. Was

We describe modifications made to KORALZ version 4.03 in order to allow for anomalous magnetic and electric dipole moments of the tau. We discuss the verification of the method at LEP 1 energies.

Juan Garcia-Bellido

In a recent paper we proposed a new model of inflation based on the soft-breaking of N=2 supersymmetric SU(2) Yang-Mills theory. The advantage of such a model is the fact that we can write an exact expression for the effective scalar potential, including perturbative and non-perturbative effects. We find that the scalar condensate that plays the role of the

Mayumi Aoki, Noriyuki Oshimo

Baryon asymmetry of the universe is generated in the supersymmetric standard model (SSM) through the charge transport mechanism mediated by top squarks. Necessary CP violation originates from a complex phase contained in mass-squared matrices of squarks and sleptons. This complex phase also gives contributions to the electric dipole moments (EDMs) of the neu