July 1998 arXiv papers — page 3

Csaba Csaki

We give a classification and overview of the confining N=1 supersymmetric gauge theories. For simplicity we consider only theories based on simple gauge groups and no tree-level superpotential. Classification of these theories can be done according to whether or not there is a superpotential generated for the confined degrees of freedom. The theories with th

A. Lima-Santos

Orthosympletic Hamiltonians derived from representations of the Temperley-Lieb algebra are presented and solved via the coordinate Bethe Ansatz. The spectra of these Hamiltonians are obtained using open and closed boundary conditions.

W. Garcia Fuertes, J. Mateos Guilarte

Electric self-dual vortices arising as BPS states in the strong coupling limit of N=2 supersymmetric Yang-Mills theory, softly broken to N=1, are reported.

C. D. Fosco, A. Lopez

We investigate some properties of a system of Dirac fermions in 2+1 dimensions, with a space dependent mass having domain wall like defects.These defects are defined by the loci of the points where the mass changes sign. In general, they will be curves lying on the spatial plane. We show how to treat the dynamics of the fermions in such a way that the existe

Maximo Banados, Thorsten Brotz, Miguel Ortiz

We compute the canonical partition function of 2+1 dimensional de Sitter space using the Euclidean $SU(2)\times SU(2)$ Chern-Simons formulation of 3d gravity with a positive cosmological constant. Firstly, we point out that one can work with a Chern-Simons theory with level $k=l/4G$, and its representations are therefore unitary for integer values of $k$. We

M. Duetsch, K. Fredenhagen

To avoid the problems which are connected with the long distance behavior of perturbative gauge theories we present a local construction of the observables which does not involve the adiabatic limit. First we construct the interacting fields as formal power series by means of causal perturbation theory. The observables are defined by BRST invariance where th

Sergiu I. Vacaru

We formulate the theory of field interactions with higher order anisotropy. The concepts of higher order anisotropic space and locally anisotropic space (in brief, ha-space and la-space) are introduced as general ones for various types of higher order extensions of Lagrange and Finsler geometry and higher dimension (Kaluza-Klein type) spaces. The spinors on

M. Caffo, H. Czyz, S. Laporta, E. Remiddi

The general lines of the derivation and the main properties of the master equations for the master amplitudes associated to a given Feynman graph are recalled. Some results for the 2-loop self-mass graph with 4 propagators are then presented.

Y. N. Srivastava, S. Palit, A. Widom, E. Sassaroli

The recent real time KARMEN anomaly for the electron neutrino counting rates (obtained from stopped muon decays) is analyzed by employing a neutrino flavor rotation model in which the muon neutrino is in a superposition of only two mass eigenstates. On the basis of experimental electron neutrino counting oscillations, we find a neutrino mass splitting $|m_2^

V. Antonelli

I consider the problem of the evaluation of the orthopositronium decay rate, including second order radiative corrections. I present a brief theoretical discussion of this problem and a review of the results available in literature, and, then, I analyze some $O(α^2)$ annihilation-type contributions, recently computed.

B. Andersson, G. Gustafson, J. Hakkinen, M. Ringner

We discuss what happens at the end of the QCD cascades. We show that, with just a few reasonable assumptions, the emission of soft gluons is constrained to produce an ordered field in the form of a helix. We describe how to modify the Lund fragmentation scheme in order to fragment such a field. Our modified fragmentation scheme yields results which are consi

L. Lesniak

A separable potential model of three coupled channels (pion-pion, kaon-antikaon and an effective four pion) has been constructed and applied in the analysis of the isoscalar S-wave pion-pion and kaon-antikaon phase shifts and inelasticities .A relatively narrow scalar resonance of mass 1400-1460 MeV has been found. This resonance is consistent with the recen

B. Pötter

Recent results from NLO QCD calculations for inclusive jet cross sections in gamma^*-gamma scattering at e+e- colliders, especially for LEP, are reported. The virtuality Q^2 of the virtual photon is non-zero and can be unlimited large. The virtuality of the second photon is zero and the spectrum is calculated with the Weizs"acker-Williams approximation.

J. C. Romao, S. Andringa

We derive the width of the Higgs boson into vector bosons. General formulas are derived both for the on-shell decay H -> VV as well for the off-shell decays, H -> V^* V and H -> V^* V^*, where V=γ,W,Z. For the off-shell decays the width of the decaying vector boson is properly included. The formulas are valid both for the Standard Model as well as for arbitr

Aleksander Zawadzki, Tadeusz Wibig, Jerzy Gawin

In search for new methods of determining the primary energy spectrum of Cosmic Rays, the attention was paid to the density spectrum measurement. New methods available at present warrant an accurateness of conclusions derived from the density spectrum measurements. The general statement about the change of the spectral index of the charged particle density sp

Hong-an Peng, Cong-feng Qiao, Jia-sheng Xu, Zhen-min He

In this paper we have demonstrated the double Q^2-rescaling model (DQ^2RM) of parton distribution functions of nucleon bounded in nucleus. With different x-region of l-A deep inelastic scattering process we take different approach: in high x-region (0.1\le x\le 0.7) we use the distorted QCD vacuum model which resulted from topologically multi -connected doma

A. T. Pierce, B. R. Webber

We investigate a modification of the $k_\perp$-clustering jet algorithm for hadron-hadron collisions, analogous to the ``Cambridge'' algorithm recently proposed for $e^+e^-$ annihilation, in which pairs of objects that are close in angle are combined preferentially. This has the effect of building jets from the inside out, with the aim of reducing th

Tadeusz Wibig

Cross sections for proton inelastic collision with different nuclei are described within the Glauber approximation. The significant difference between approximate ``Glauber'' formula and exact calculations with geometrical scaling assumption is shown for very high energy cross section calculations. According to obtained results values of proton-proto

Tadeusz Wibig

Between the initial excitation of nucleons by the passing throughout each other and the final cascading of newly created hadrons there should be considered one more step. We call it the second step cascading process. It acts as an interaction of wounded nucleon from one nucleus with another nucleon from the same nucleus. This mechanism leads to the significa

V. S. Fadin

I discuss radiative corrections to the BFKL equation for high energy cross sections in perturbative QCD. Due to the gluon Reggeization in the next-to-leading $\ln s$ approximation, the form of the BFKL equation remains unchanged and the corrections to the BFKL kernel are expressed in terms of the two-loop contribution to the gluon Regge trajectory, the one-l

V. S. Fadin

The representation of the total cross section at high energy $\sqrt s$ in the next-to-leading $\ln s$ approximation is given with definition of the impact factors and explicit expression for the BFKL kernel. The estimate of the Pomeron intercept and the next-to-leading contributions to anomalous dimensions near $j=1$ are presented.

Xerxes Tata

We survey strategies generally employed for SUSY discovery at colliders and then discuss how these may have to be altered for SUSY searches at the Tevatron if $\tanβ$ is large. We also discuss the reach of the Tevatron and the LHC in gauge-mediated SUSY breaking scenarios, assuming that the NLSP decays into photons. Finally, we briefly recapitulate measureme

M. Alford, A. Kapustin, F. Wilczek

Standard lattice fermion algorithms run into the well-known sign problem at real chemical potential. In this paper we investigate the possibility of using imaginary chemical potential, and argue that it has advantages over other methods, particularly for probing the physics at finite temperature as well as density. As a feasibility study, we present numerica

B. Gittelman

This is a discussion of the main branching fractions of B Meson decays $(b\to cW^{-})$. A summary of what has been measured and what remains unmeasured is presented.

B. Abbott

This paper presents the first measurement of the inclusive J/Psi production cross section in the forward pseudorapidity region 2.5<|eta|<3.7 in ppbar collisions at sqrt(s)=1.8TeV. The results are based on 9.8 pb-1 of data collected using the D0 detector at the Fermilab Tevatron Collider. The inclusive J/Psi cross section for transverse momenta between 1 and

Marek Tasevsky

A review of recent jet measurements of the photon structure from the H1 experiment at HERA. The scale and the virtuality dependence of the effective parton distribution function of the photon is discussed.

J. Podolsky

We investigate a class of impulsive gravitational waves which propagate either in Minkowski or in the (anti-)de Sitter background. These waves are constructed as impulsive members of the Kundt class $P(Λ)$ of non-twisting, non-expanding type N solutions of vacuum Einstein equations with a cosmological constant $Λ$. We show that the only non-trivial waves of

V. Dzhunushaliev

A geometrical model of electric charge is proposed. This model has ``naked&#39;&#39; charge screened with a ``fur - coat&#39;&#39; consisting of virtual wormholes. The 5D wormhole solution in the Kaluza - Klein theory is the ``naked&#39;&#39; charge. The splitting off of the 5D dimension happens on the two spheres (null surfaces) bounding this 5D wormhole. T

Winfried Zimdahl, Alexander B. Balakin

The particles of a classical relativistic gas are supposed to move under the influence of a quasilinear (in the particle four-momenta), self-interacting force inbetween elastic, binary collisions. This force which is completely fixed by the equilibrium conditions of the gas, gives rise to an effective viscous pressure on the fluid phenomenological level. Ear

Parthasarathi Majumdar

An elementary introduction is given to the problem of black hole entropy as formulated by Bekenstein and Hawking. The information theoretic basis of Bekenstein&#39;s formulation is briefly reviewed and compared with Hawking&#39;s approach. The issue of calculating the entropy by actual counting of microstates is taken up next within two currently popular app

E. V. Goldstein, M. G. Moore, O. Zobay, P. Meystre

We give a brief overview of the way atomic physics is now developing in a way reminiscent of the optics revolution of the 1960&#39;s. Thanks in particular to recent developments in atomic trapping and cooling, the new field of atom optics is rapidly leading to exciting new developments such as nonlinear atom optics and quantum atom optics. We illustrate thes

Christopher Mudry, P. W. Brouwer, B. I. Halperin, V. Gurarie

We reconsider the recently proposed connection between density of states in the so-called ``non-hermitian quantum mechanics&#39;&#39; and the localization length for a particle moving in random potential. We argue that it is indeed possible to find the localization length from the density of states of a non-hermitian random ``Hamiltonian&#39;&#39;. However,

L. Reatto, A. Parola, L. Salasnich

We study the properties of a Bose-Einstein condensed cloud of atoms with negative scattering length confined in a harmonic trap. When a realistic non local (finite range) effective interaction is taken into account, we find that, besides the known low density metastable solution, a new branch of Bose condensate appears at higher density. This state is self-b

Martin S. Kochman&#39;ski

In the paper nonlinear transformations of the Jordan-Wigner (JW) type are introduced in the form different from the ones known previously, for the purpose of expressing multi-index Pauli operators in terms of multi-index Fermi creation and annihilation operators. These JW transformations in the general case being a subject of a rather complicated algebra of

Ganpathy Murthy, K. Park, R. Shankar, J. K. Jain

The microscopic approach of Murthy and Shankar, which has recently been used to calculate the transport gaps of quantum Hall states with fractions p/(2ps+1), also implies scaling relations between gaps within a single sequence (fixed s) as well as between gaps of corresponding states in different sequences. This work tests these relations for a system of ele

Michael Schreiber, Frank Epperlein, Thomas Vojta

The combined influence of disorder and interactions on the transport properties of electrons in one dimension is investigated. The numerical simulations are carried out by means of the Hartree-Fock-based diagonalization (HFD), a very efficient method to determine the low-energy properties of a disordered many-particle system. We find that the conductance of

R. Moessner, J. T. Chalker

We study the ground-state and low-energy properties of classical vector spin models with nearest-neighbour antiferromagnetic interactions on a class of geometrically frustrated lattices which includes the kagome and pyrochlore lattices. We explore the behaviour of these magnets that results from their large ground-state degeneracies, emphasising universal fe

M. Letz

Deviations from Fermi liquid behavior are well documented in the normal state of the cuprate superconductors, and some of these differences seem to be related to pre-transitional features appearing at temperatures above T$_c$. The observation of a pseudogap, e.g. in ARPES experiments, is a familiar example of this physics. One potential explanation for this

Kirill N. Alekseev, Gennady P. Berman, David K. Campbell

We consider the motion of ballistic electrons within a superlattice miniband under the influence of an alternating electric field. We show that the interaction of electrons with the self-consistent electromagnetic field generated by the electron current may lead to the transition from regular to chaotic dynamics. We estimate the conditions for the experiment

D. N. Aristov

We consider the static anomalous Cooper loop for the electron gas of arbitrary spatial dimensionality, D. This object enters the mean-field equation for the superconducting temperature, T_c. The closed expression in r- space is found at T=0 as an analytical function of D. Its counterpart in q-space has a logarithmic singularity at q=0 and no singularities at

C. M. Marcus

Mesoscopic structures are generally operated in an open-loop configuration, whereas most practical electronics including quantum interference devices such as SQUIDs are operated closed-loop, taking advantage of feedback. This paper presents some basic considerations on the use of feedback in mesoscopic samples with universal statistical properties. The contr

Hiroto Kobayashi, Naomichi Hatano, Seiji Miyashita

Non-adiabatic transitions are studied in a spin-boson model with multiple scattering points. In order to generalize the Landau-Zener formula, which describes the case of a single scattering point, we define an ``effective gap&#39;&#39; for a set of scattering points. The generalized formula agrees very well with numerical results of the non-adiabatic dynamic

M. Bayindir, B. Tanatar

We study Bose-Einstein condensation phenomenon in a two-dimensional (2D) system of bosons subjected to an harmonic oscillator type confining potential. The interaction among the 2D bosons is described by a delta-function in configuration space. Solving the Gross-Pitaevskii equation within the two-fluid model we calculate the condensate fraction, ground state

Ryo Tamura, Masaru Tsukada

The electron transport through the nanotube junctions which connect the different metallic nanotubes by a pair of a pentagonal defect and a heptagonal defect is investigated by Landauer&#39;s formula and the effective mass approximation. From our previous calculations based on the tight binding model, it has been known that the conductance is determined almo

Haowen Xi, Comer Duncan

We present three-dimensional numerical simulations of the classical Taylor experiment on droplet deformation within a shear flow. We have used the promising Lattice-Boltzmann method numerical scheme to simulate single droplet deformation and breakup under simple shear flow. We first compute the deformation of the droplet and find excellent agreement with the

J. M. Ponder, D. Burstein, R. W. O&#39;Connell, J. A. Rose

Observations in integrated light (2200-4800 A, 8 to 11 A resolution, S/N > 20) of 4 M31 globular clusters and of the cores of six gE galaxies made with the HST/FOS are presented and analyzed. These data are supplemented by IUE observations of M32, Galactic globulars and stars. From these data we measure UV colors and absorption line strength (ALS) indices, i

Stephen P. Boughn

Using the HEAO1 A2 full sky, 2-10 keV X-ray map evidence is found for the presence of diffuse X-ray emission in the plane of the local supercluster. Fitting this diffuse component with a simple ``pillbox&#39;&#39; model implies a volume X-ray emissivity of 3.0 +- 0.3 x 10**39 (20 Mpc/R) erg/s/Mpc**3 where R is the radius of the supercluster and the error is

G. W. Marcy, R. P. Butler, S. S. Vogt, D. A. Fischer

Doppler measurements of the M4 dwarf star, Gliese 876, taken at both Lick and Keck Observatory reveal periodic, Keplerian velocity variations with a period of 61 days. The orbital fit implies that the companion has a mass of, M = 2.1 MJUP /sin i, an orbital eccentricity of, e = 0.27+-0.03, and a semimajor axis of, a = 0.21 AU. The planet is the first found a

Jeremy S. Heyl, S. R. Kulkarni

Ultramagnetized neutron stars or magnetars have been invoked to explain several astrophysical phenomena. We examine how the magnetic field of a magnetar will decay over time and how this decay affects the cooling of the object. We find that for sufficiently strong nascent fields, field decay alters the cooling evolution significantly relative to similarly ma

Eelco van Kampen

The surface mass density of a cluster of galaxies, and thus its total mass, can be estimated from its lens magnification. The magnification can be determined from the variation in number counts of its background galaxies. In the weak lensing approximation the surface mass density is a linear function of the magnification. However, most observational data is

David A. Kornreich, Martha P. Haynes, Richard V. E. Lovelace

A photometric method for quantifying deviations from axisymmetry in optical images of disk galaxies is applied to a sample of 32 face-on and nearly face-on spirals. The method involves comparing the relative fluxes contained within trapezoidal sectors arranged symmetrically about the galaxy center of light, excluding the bulge and/or barred regions. Such a m

J. S. Clark, R. P. Fender, L. B. F. M. Waters, S. M. Dougherty

We present 10 micron, ISO-SWS and Australia Telescope Compact Array observations of the region in the cluster Wd1 in Ara centred on the B[e] star Ara C. An ISO-SWS spectrum reveals emission from highly ionised species in the vicinity of the star, suggesting a secondary source of excitation in the region. We find strong radio emission at both 3.5cm and 6.3cm,

Andrzej A. Zdziarski, Juri Poutanen, Joanna Mikolajewska, Marek Gierlinski

We present X-ray/gamma-ray spectra of the binary GX 339-4 observed in the hard state simultaneously by Ginga and CGRO OSSE during an outburst in 1991 September. The Ginga spectra are well represented by a power law with a photon spectral index of 1.75 and a moderately-strong Compton reflection component with a fluorescent Fe K alpha line. The OSSE data requi

The PLANET Collaboration, M. Albrow, J. -P. Beaulieu, P. Birch

PLANET (the Probing Lensing Anomalies NETwork) is a worldwide collaboration of astronomers whose primary goal is to monitor microlensing events densely and precisely in order to detect and study anomalies that contain information about Galactic lenses and sources that would otherwise be unobtainable. The results of PLANET&#39;s highly successful first year o

Bharat Ratra, Ken Ganga, Radoslaw Stompor, Naoshi Sugiyama

We use data from the ARGO cosmic microwave background (CMB) anisotropy experiment to constrain cosmogonies. We account for the ARGO beamwidth and calibration uncertainties, and marginalize over the offset removed from the data. Our derived amplitudes of the CMB anisotropy detected by the ARGO experiment are smaller than those derived previously. We consider

A. Muecke, M. Pohl

We present a model for estimating the blazar contribution to the extragalactic gamma-ray background (EGRB) in the EGRET energy range. It is based on inverse-Compton scattering as the dominant gamma-ray production process in the jets of flat spectrum radio quasars (FSRQs) and BL Lac objects, and on the unification scheme of radio-loud AGN. Depending on the ev

Mario Mateo, Edward W. Olszewski, Steven S. Vogt, Michael J. Keane

We present radial velocities of 33 red giants in the Leo I dSph galaxy obtained from spectra taken with the HIRES echelle spectrograph on the Keck I telescope. These data have a mean precision of 2.2 km/s and lead to estimates of the central velocity dispersion and systemic velocity of Leo I of 8.8 +- 1.3 km/s, and 287.0 +- 1.9 km/s, respectively. The system

A. S. Fruchter, E. Pian, S. E. Thorsett, L. E. Bergeron

We report on observations of the fading optical counterpart of the gamma-ray burst GRB 970228, made with the Hubble Space Telescope STIS CCD approximately six months after outburst and with the HST/NICMOS and Keck/NIRC approximately one year after outburst. The unresolved counterpart is detected by STIS at V=28.0 +/- 0.25, consistent with a continued power-l

A. Furusaki, S. C. Zhang

The zero-temperature dynamical spin-spin correlation functions are calculated for the spin-1/2 two-leg Heisenberg ladder in a magnetic field above the lower critical field Hc1. The dynamical structure factors are calculated which exhibit both massless and massive excitations. These modes appear in different sectors characterized by the parity in the rung dir

Jeffrey A. Harvey

In recent work Kachru, Kumar and Silverstein introduced a special class of non-supersymmetric type II string theories in which the cosmological constant vanishes at the first two orders of perturbation theory. Heuristic arguments suggest the cosmological constant may vanish in these theories to all orders in perturbation theory leading to a flat potential fo

Keith L. Frost, Laurence G. Yaffe

We examine periodic, spherically symmetric, classical solutions of SU(2)-Higgs theory in four-dimensional Euclidean space. Classical perturbation theory is used to construct periodic time-dependent solutions in the neighborhood of the static sphaleron. The behavior of the action, as a function of period, changes character depending on the value of the Higgs

Glenn Barnich

The most convenient tool to study the renormalization of a Lagrangian field theory invariant under non linear local or global symmetries is the proper solution to the master equation of the extended antifield formalism. It is shown that, from the knowledge of the BRST cohomology, it is possible to explicitly construct a further extension of the formalism con

N. Kontoleon, D. L. Wiltshire

We demonstrate in the context of the minisuperspace model consisting of a closed Friedmann-Robertson-Walker universe coupled to a scalar field that Vilenkin&#39;s tunneling wavefunction can only be consistently defined for particular choices of operator ordering in the Wheeler-DeWitt equation. The requirement of regularity of the wavefunction has the particu

Robert E. Lopez, Michael S. Turner

Within the standard models of particle physics and cosmology we have calculated the big-bang prediction for the primordial abundance of \he to a theoretical uncertainty of less than $0.1 \pct$ $(δY_P < \pm 0.0002)$, improving the current theoretical precision by a factor of 10. At this accuracy the uncertainty in the abundance is dominated by the experimenta

Hitoshi Nishino

We construct supergravity theories in twelve and thirteen dimensions with the respective signatures (10,2) and (11,2) with some technical details. Starting with N=1 supergravity in 10+2 dimensions coupled to Green-Schwarz superstring, we give N=2 chiral supergravity in 10+2 dimensions with its couplings to super (2+2)-brane. We also build an N=1 supergravity

A. B. Pestov, Bijan Saha

The gauge symmetry inherent in the concept of manifold has been discussed. Within the scope of this symmetry the linear connection or displacement field can be considered as a natural gauge field on the manifold. The gauge invariant equations for the displacement field have been derived. It has been shown that the energy-momentum tensor of this field conserv

M. A. Ivanov, J. G. Korner, V. E. Lyubovitskij, A. G. Rusetsky

We study one-pion transitions between charm baryon states in the framework of a relativistic three-quark model. We calculate the charm baryon-pion coupling factors that govern the S-wave, P-wave and D-wave one-pion transitions from the s-wave and the lowest lying p-wave charm baryon states down to the s-wave charm baryon states. For these we obtain: g_{Σ_cΛ_

Guifre Vidal

In the context of quantifying entanglement we study those functions of a multipartite state which do not increase under the set of local transformations. A mathematical characterization of these monotone magnitudes is presented. They are then related to optimal strategies of conversion of shared states. More detailed results are presented for pure states of

L. O. Silva, R. Bingham, J. M. Dawson, W. B. Mori

We derive the force exerted in the background plasma by an arbitrary distribution of non interacting quasi-particles, corresponding to either collective excitations of the plasma (plasmons, phonons) or em dressed particles (photons, neutrinos). Our approach is based on the effective Hamiltonian describing the quasi-classical dynamics of the individual partic

L. O. Silva, R. Bingham, J. M. Dawson, P. K. Shukla

The derivation of the ponderomotive force due to neutrinos by Hardy and Melrose, Phys.Rev.D v.54, p.6491 (1996) is based on a flawed analysis of the ponderomotive force concept. Their conclusions also contain an erroneous physical assumption related to the neutrino emission in supernovae. A correct analysis shows the importance of the ponderomotive force due

M. Berkooz, Soo-Jong Rey

We discuss stability of non-supersymmetric compactification of M-theory and string theory of the form AdS * X, and their dual non-supersymmetric interacting conformal field theories. We argue some of the difficulties in controlling 1/N-corrections disappear in the cases that the large-N dual conformal field theory has no invariant marginal operators (and in

H. Pu, C. K. Law, J. H. Eberly, N. P. Bigelow

We consider the intrinsic stability of the vortex states of a pure Bose-Einstein condensate confined in a harmonic potential under the effects of coherent atom-atom interaction. We find that stable vortices can be supported, and that vortex stability can be controlled by changing the inter-particle interaction strength. At unstable regimes, a vortex will spo

H. P. Breuer, B. Kappler, F. Petruccione

A fast simulation algorithm for the calculation of multitime correlation functions of open quantum systems is presented. It is demonstrated that any stochastic process which ``unravels&#39;&#39; the quantum Master equation can be used for the calculation of matrix elements of reduced Heisenberg picture operators, and thus for the calculation of multitime cor

Heinz-Peter Breuer, Bernd Kappler, Francesco Petruccione

Within the framework of probability distributions on projective Hilbert space a scheme for the calculation of multitime correlation functions is developed. The starting point is the Markovian stochastic wave function description of an open quantum system coupled to an environment consisting of an ensemble of harmonic oscillators in arbitrary pure or mixed st

D. A. Ross

A modification of Grover&#39;s algorithm is proposed, which can be used directly as a fast database search. An explicit two q-bit example is displayed in detail. We discuss the case where the database has multiple entries corresponding to the same target value.

K. -A. Suominen, E. Tiesinga, P. S. Julienne

Magnetically trapped neutral atoms can be cooled with the evaporation technique. This is typically done by using a radiofrequency (rf) field that adiabatically couples trapped and untrapped internal atomic states for atoms with kinetic energies above a value set by the field frequency. The rf-field can also induce nonadiabatic changes of internal atomic spin

Bruno Huepper, Eli Pollak

A formula of Doetsch ({\em Math. Zeitschr.} {\bf 42}, 263 (1937)) is generalized and used to numerically invert the one-sided Laplace transform ${\hat C}(β)$. The necessary input is only the values of ${\hat C}(β)$ on the positive real axis. The method is applicable provided that the functions $\hat{C}(β)$ belong to the function space $L^2_α$ defined by the

N. N. Scoccola, D. O. Riska

The rational map ansatz for light nuclei in the Skyrme model is shown to imply the existence of an η-^4He bound state, with a binding energy of ~ 30 KeV.

R. Myrzakulov

Using the differential geometry of curves and surfaces the Lakshmanan equivalent counterpart of the M-XXII equation is found ... .

Mark Byrd

The left and right invariant vector fields are calculated in an ``Euler angle&#39;&#39; type parameterization for the group manifold of SU(3), referred to here as Euler coordinates. The corresponding left and right invariant one-forms are then calculated. This enables the calculation of the invariant volume element or Haar measure. These are then used to des

Bertfried Fauser

It can be shown that it is possible to find a representation of Hecke algebras within Clifford algebras of multivectors. These Clifford algebras possess a unique gradation and a possibly non-symmetric bilinear form. Hecke algebra representations can be classified, for non-generic q, by Young tableaux of the symmetric group due to the isomorphy of the group a

T. D. Palev, N. I. Stoilova

A class of highest weight irreducible representations of the algebra $U_h(A_\infty)$, the quantum analogue of the completion and central extension $A_\infty$ of the Lie algebra $gl_\infty$, is constructed. It is considerably larger than the class of representations known so far. Within each module a basis is introduced and the transformation relations of the

Juan P. Aparicio, Fabian H. Gaioli, Edgardo T. Garcia Alvarez

Several quantum proper time derivatives are obtained from the Beck one in the usual framework of relativistic quantum mechanics (spin 1/2 case). The ``scalar Hamiltonians&#39;&#39; of these derivatives should be thought of as the conjugate variables of the proper time. Then, the Hamiltonians would play the role of mass operators, suggesting the formulation o

Fabian H. Gaioli, Edgardo T. Garcia Alvarez

This work is a comment on Ryder&#39;s derivation of the Dirac equation, with emphasis on the physical contents of this equation: the notion of particles and antiparticles according to the Stueckelberg-Feynman interpretation, the opposite intrinsic parity between particles and antiparticles, and the spin.

M. Bertolini, P. Fre, F. Hussain, R. Iengo

We explore the connection between D-branes and black holes in one particular case: a $D3$-brane compactified to four dimensions on $T^6/Z_3$. Using the $D$-brane boundary state description we show the equivalence with a double extremal N=2 black hole solution of four dimensional supergravity.

M. J. O&#39;Loughlin, S. Randjbar-Daemi

We study a target space geometry of the form $AdS_3 \times {\bf R}$ for the $(2,1)$ heterotic string. This target space arises as the near horizon limit of a solitonic configuration in 2+2 dimensions. We investigate the null isometries of this space and discuss the reduction to 1+1 dimensions of the target space geometry arising from the consistent gauging o

A. Campos, K. Holland, U. -J. Wiese

Complete wetting is a universal phenomenon associated with interfaces separating coexisting phases. For example, in the pure gluon theory, at $T_c$ an interface separating two distinct high-temperature deconfined phases splits into two confined-deconfined interfaces with a complete wetting layer of confined phase between them. In supersymmetric Yang-Mills th

Renata Kallosh

The classical superconformal actions of branes in adS superspaces have a closed form depending on a matrix $M^2$ quadratic in fermions, as found in hep-th/9805217. One can gauge-fix the local $κ$-symmetry using the Killing spinors of the brane in the bulk. We show that in such gauges the superconformal actions are simplified dramatically since $M^2=0$ in all

Ofer Aharony, Edward Witten

Upon compactification on a circle, SU(N) gauge theory with all fields in the adjoint representation acquires a $Z_N$ global symmetry because the center of the gauge group is $Z_N$. For N=4 super Yang-Mills theory, we show how this $Z_N$ &#34;topological symmetry&#34; arises in the context of the AdS/CFT correspondence, and why the symmetry group is $Z_N$ rat

A. V. Smilga

We study the spectrum of the domain walls interpolating between different chirally asymmetric vacua in supersymmetric QCD with the SU(N) gauge group and including N-1 pairs of chiral matter multiplets in fundamental and anti-fundamental representations. There are always &#34;real walls&#34; interpolating between the chirally symmetric and a chirally asymmetr

Igor Bandos

A brief introduction to superembedding approach (SEA) in its variant based on the generalized action principle (GAP) for super-p-branes is given. A role of harmonic variables for Lorentz group is stressed. A relation of the GAP with complete superfield actions is noted. Recent applications in studying of Dirichlet branes (super-Dp-branes) and M-branes are di

H. R. Christiansen, C. Nuñez, F. A. Schaposnik

We discuss Bogomol&#39;nyi equations for general gauge theories (depending on the two Maxwell invariants $F^{μν} F_{μν}$ and $\tilde F^{μν} F_{μν}$) coupled to Higgs scalars. By analysing their supersymmetric extension, we explicitly show why the resulting BPS structure is insensitive to the particular form of the gauge Lagrangian: Maxwell, Born-Infeld or mo

Arjun Berera

A general overview is given of the warm inflation scenario.

Keith R. Dienes, Emilian Dudas, Tony Gherghetta

In this talk, we summarize our recent proposal for lowering the scale of grand unification to the TeV range though the appearance of extra spacetime dimensions. Particular emphasis is placed on the perturbativity and predictivity of our scenario, as well as its sensitivity to unification-scale effects. (Proceedings of invited talks given by KRD at PASCOS &#3

D. A. Steer

We discuss and summarise the predictions of a model for the non-equilibrium evolution of a network of cosmic strings initially containing {\em only loops} and {\em no infinite strings}. The results are of interest given recent work highlighting the problems with structure formation from the standard cosmic string scenario.

S. B. Barr

A non-axion solution to the Strong CP Problem is proposed that works even in the context of gravity-mediated supersymmetry breaking. Both $ε&#39;/ε$ and indirect CP violation in the $B-\bar{B}$ are predicted to be unobservably small. $μ\longrightarrow e γ$ is predicted to arise, typically, with branching ration $3 \times 10^{-12}$. A new source of dark matte

Y. Kouchi, A. Shinbori, Y. Takeuchi, S. Y. Tsai

We demonstrate how one may identify or constrain possible violation of $CP$, $T$ and $CPT$ symmetries in the $K^0$-$\bar{K^0}$ system in a way as phenomenological and comprehensive as possibie. For this purpose, we first introduce parameters which represent violation of these symmetries in mixing parameters and decay amplitudes in a well-defined way. After d

Morimitsu Tanimoto

Recent atmospheric neutrino data at Super-Kamiokande suggest the near-maximal flavor mixing. Models for the lepton mass matrix, which give the near-maximal flavor mixing, are discussed in this report. Mass matrix models are classified according to the mechanism providing the large flavor mixing, and those are reviewed briefly. &#34;Naturalness&#34; of the ma

Antonio Riotto

These lectures provide a pedagogical review of the present status of theories explaining the observed baryon asymmetry of the Universe. Particular emphasis is given on GUT baryogenesis and electroweak baryogenesis. The key issues, the unresolved problems and the very recent developments, such as GUT baryogenesis during preheating, are explained. Some exercis

I T Drummond

A model for string breaking on the lattice is formulated using strong coupling ideas. It gives an explicit picture of string breaking, in the presence of dynamical quarks, as a mixing process between a string state and a two-meson state. An analysis of the Wilson loop shows that the evolution of the mixing angle as a function of separation may obscure the ex