October 1996 arXiv papers — page 4

N. G. Stefanis, A. I. Karanikas, C. N. Ktorides

An effective field theoretic description of the Isgur-Wise function in heavy-meson transitions is presented which emulates soft interactions by a fermion worldline with an infinitesimal self-intersecting loop. A point-splitting regularization technique is used, which replaces pointlike worldlines by ``ribbons'' in the sense of Witten. The calculated

W. Beenakker, R. H"opker, M. Spira, P. M. Zerwas

We have determined the theoretical predictions for the cross-sections of squark and gluino production at $\ppb$ and $pp$ colliders (Tevatron and LHC) in next-to-leading order of supersymmetric QCD. By reducing the dependence on the renormalization/factorization scale considerably, the theoretically predicted values for the cross-sections are much more stable

T. Kleinwort, G. Kramer

We have calculated inclusive two-jet production in photon-photon collisions superimposing direct, single-resolved and double-resolved cross sections for center-of-mass energies of TRISTAN and LEP1.5. All three contributions are calculated up to next-to-leading order. The results are compared with recent experimental data. Three NLO sets of parton distributio

C. Boros, Liang Zuo-tang, Meng Ta-chung

Talk presented by Meng Ta-chung at the 12th International Symposium on High Energy Spin Physics, SPIN96, Amsterdam, September 10-14,1996.

C. Boros, Liang Zuo-tang, Meng Ta-chung

It is shown that the polarization in inclusive hyperon production and the left-right asymmetries in meson and hyperon production are closely related to one other. They can be understood in terms of a picture in which the orbital motion of valence quarks of the scattering hadrons play an important role.

F. Cannata, J-P. Dedonder, M. P. Locher

The pion Bose-Einstein correlation parameters determined by OPAL show a weak dependence on pion multiplicity. We argue that the observed increase of the interaction radius, and the decrease of the chaoticity parameter could be due to an increasing fraction of other mesons at high multiplicities.

Andrea Romanino, Alessandro Strumia

We study quark and electron EDMs generated by Yukawa couplings in supersymmetric models with different gauge groups, using the EDM properties under flavour transformations. In the MSSM (or if soft terms are mediated below the unification scale) the one loop contributions to the neutron EDM are smaller than in previous computations based on numerical methods,

T. Haberichter, H. Reinhardt, N. N. Scoccola, H. Weigel

The radiative decays of the $(3/2)^+$ baryons are studied in the three flavor generalization of the Skyrme model. The kaon fields are treated in the slow rotator approach which properly accounts for the observed deviations from the $U$-spin relations for the hyperon magnetic moments. This makes possible a critical discussion of the $U$-spin selection rules f

Roberto Ugoccioni

The possibility to relate multiplicity distributions and their moments, as measured in the hadronic final state in e(+)e(-) annihilation, to features of the initial partonic state is analyzed from a theoretical and phenomenological point of view. Recent developments on the subject are discussed.

V. V. Kiselev

The value of $α_s(m_Z)=0.106\pm 0.005$ is obtained in a scheme of sum rules for the leptonic constants of the vector $nS$-levels in the heavy $(\bar b b)$-quarkonium.

P. Binetruy, S. Lavignac, S. Petcov, P. Ramond

We show that models with an abelian family symmetry which accounts for the observed hierarchies of masses and mixings in the quark sector may also accomodate quasi-degeneracies in the neutrino mass spectrum. Such approximate degeneracies are, in this context, associated with large mixing angles. The parameters of this class of models are constrained. We disc

A. I. Signal

We calculate all twist-two, three and four parton distribution functions involving two quark correlations using the wavefunction of the MIT bag model. The distributions are evolved up to experimental scales and combined to give the various nucleon structure functions. Comparisons with recent experimental data on higher twist structure functions at moderate v

Martin Baeker

We present a new multigrid method called neural multigrid which is based on joining multigrid ideas with concepts from neural nets. The main idea is to use the Greenbaum criterion as a cost functional for the neural net. The algorithm is able to learn efficient interpolation operators in the case of the ordered Laplace equation with only a very small critica

A. A. Coley

Self-similarity in general relativity is briefly reviewed and the differences between self-similarity of the first kind and generalized self-similarity are discussed. The covariant notion of a kinematic self-similarity in the context of relativistic fluid mechanics is defined. Various mathematical and physical properties of spacetimes admitting a kinematic s

Takahiro Tanaka, Misao Sasaki

The quantization of gravitational waves in the Milne universe is discussed. The relation between positive frequency functions of the gravitational waves in the Milne universe and those in the Minkowski universe is clarified. Implications to the one-bubble open inflation scenario are also discussed.

H. Noh, J. Hwang

We present a set of equations describing the cosmological gravitational wave in a gravity theory with quadratic order gravitational coupling terms which naturally arise in quantum correction procedures. It is known that the gravitational wave equation in the gravity theories with a general $f(R)$ term in the action leads to a second order differential equati

L. E. Simone, S. W. Leonard, E. Poisson, C. M. Will

Gravitational radiation can be expressed in terms of an infinite series of radiative, symmetric trace-free (STF) multipole moments which can be connected to the behavior of the source. We consider a truncated model for gravitational radiation from binary systems in which each STF mass and current moment of order l is given by the lowest-order, Newtonian-like

Man Chun Leung

We study uniqueness of positive solutions to the conformal scalar curvature equation on complete Riemannian manifolds with constant negative scalar curvature. We apply the results to show that conformal transformations on certain complete Riemannian manifolds of constant negative scalar curvature are isometries. We also study uniqueness of complete positive

John Neergaard, Marcel den Nijs

Stationary states in KPZ type growth have interesting short distance properties. We find that typically they are skewed and lack particle-hole symmetry. E.g., hill-tops are typically flatter than valley bottoms, and all odd moments of the height distribution function are non-zero. Stationary state skewness can be turned on and off in the 1+1 dimensional RSOS

A. N. Tahvildar-Zadeh, M. Jarrell, J. K. Freericks

The asymmetric infinite-dimensional periodic Anderson model is examined with a quantum Monte Carlo simulation. For small conduction band filling, we find a severe reduction in the Kondo scale, compared to the impurity value, as well as protracted spin screening consistent with some recent controversial photoemission experiments. The Kondo screening drives a

A. Griffin, Wen-Chin Wu, S. Stringari

We discuss the collective modes of a trapped Bose gas in the hydrodynamic regime where atomic collisions ensure local thermal equilibrium for the distribution function. Starting from the conservation laws, in the linearized limit we derive a closed equation for the velocity fluctuations in a trapped Bose gas above the Bose-Einstein transition temperature. Ex

D. Bazeia, J. R. S. Nascimento, D. Toledo

In this paper we offer an alternate route for investigating soliton solutions in hydrogen-bonded chains. This is done by examining a class of systems of two coupled real scalar fields. We show that this route allows investigating several models for hydrogen-bonded chains in a unified manner. We also show how to investigate interesting issues, in particular t

C. J. Lambert, R. Raimondi, V. Sweeney, A. F. Volkov

In this paper we derive effective boundary conditions connecting the quasiclassical Green's function through tunnel barriers in superconducting - normal hybrid (S-N or S-S') structures in the dirty limit. Our work extends previous treatments confined to the small transparency limit. This is achieved by an expansion in the small parameter $r^{-1}=T/2(

H. Y. Huang, V. Popkov, F. Y. Wu

We consider a three-dimensional lattice model consisting of layers of vertex models coupled with interlayer interactions. For a particular non-trivial interlayer interaction between charge-conserving vertex models and using a transfer matrix approach, we show that the eigenvalues and eigenvectors of the transfer matrix are related to those of the two-dimensi

Armelle Barelli, Jean Bellissard, Philippe Jacquod, Dima L. Shepelyansky

The problem of two interacting particles in a quasiperiodic potential is addressed. Using analytical and numerical methods, we explore the spectral properties and eigenstates structure from the weak to the strong interaction case. More precisely, a semiclassical approach based on non commutative geometry techniques permits to understand the intricate structu

Eli Eisenberg, Asher Baram

The effect of diffusional relaxation on the random sequential deposition process is studied in the limit of fast deposition. Expression for the coverage as a function of time are analytically derived for both the short-time and long-time regimes. These results are tested and compared with numerical simulations.

Jian Wang, Qingrong Zheng, Hong Guo

We have studied the weakly non-linear quantum transport properties of a two-dimensional quantum wire which can be solved exactly. The non-linear transport coefficients have been calculated and interesting physical properties revealed. In particular we found that as the incoming electron energy approaches a resonant point given by energy $E=E_r$, where the tr

Min Zhang

Several methods have been proposed for processing a corpus to induce a tagset for the sub-language represented by the corpus. This paper examines a structured-tag word classification method introduced by McMahon (1994) and discussed further by McMahon & Smith (1995) in cmp-lg/9503011 . Two major variations, (1) non-random initial assignment of words to class

H. -Thomas Janka

The results of recent multi-dimensional simulations of type-II supernovae are reviewed. They show that convective instabilities in the collapsed stellar core might play an important role already during the first second after the formation of the supernova shock. Convectively unstable situations occur below and near the neutrinosphere as well as in the neutri

M. Tavani, A. Fruchter, S. N. Zhang, B. A. Harmon

We report the results of multiwavelength observations of the superluminal X-ray transient GRO J1655-40 during and following the prominent hard X-ray outburst of March-April 1995. GRO J1655-40 was continuously monitored by BATSE on board CGRO, and repeatedly observed in the radio and optical bands from the ground. About a month after the onset of the hard X-r

Jerome A. Orosz, Charles D. Bailyn

We report photometric and spectroscopic observations of the black hole binary GRO J1655-40 in complete quiescence. In contrast to the 1995 photometry, the light curves from 1996 are almost completely dominated by ellipsoidal modulations from the secondary star. Model fits to the light curves, which take into account the temperature profile of the accretion d

I. -A. Yadigaroglu, Roger W. Romani

We revisit the association of unidentified Galactic plane EGRET sources with tracers of recent massive star formation and death. Up-to-date catalogs of OB associations, SNRs, young pulsars, HII regions and young open clusters were used in finding counterparts for a recent list of EGRET sources. It has been argued for some time that EGRET source positions are

F. K. Liu, B. F. Liu, G. Z. Xie

All data available in B band for the BL Lac object MRK421 from 22 publications are used to construct a historical light curve, dating back to 1900. It is found that the light curve is very complicated and consists of a set of outbursts with very large duration. The brightness of MRK421 varies from 11.6 magnitude to more than 16 magnitude. Analyses with Jurke

F. Hammer, P. Teyssandier, E. J. Shaya, I. M. Gioia

A deep HST image of the MS 2137-2353 core has revealed detailed morphological structures in two arc systems, which are modelled and well reproduced after a complete analysis of the lensing properties of the dark matter component. Latter could have a simple elliptical mass distribution with ellipticity and angular orientation similar to those of the visible a

The Virgo Consortium, :, A. Jenkins, C. S. Frenk

We report on work in progress by the Virgo consortium, a collaboration set up to carry out large simulations of the formation of galaxies and large-scale structure exploiting the latest generation of parallel supercomputers. We show results of $256^3$ particle N-body simulations of the clustering evolution of dark matter in four cold dark matter models with

J. A. Grifols, E. Masso

Should $U(1)$ long-range forces be associated to electron, muon and/or tau quantum number then their ''fine structure constants" are seen to be bound by nucleosynthesis data to be less than about $1.7 \times 10^{-11}$. For $τ$ and $μ$ this is the best upper limit up to date

M. Cappi, M. Matsuoka, A. Comastri, W. Brinkmann

Results are presented on the X-ray properties of 9 high-redshift (1.2 < z < 3.4) radio-loud quasars (RLQs) observed by ASCA (10 observations) and ROSAT (11 observations, for a subset of 6 quasars). New ASCA observations of S5 0014+81 (z = 3.38) and S5 0836+71 (z = 2.17) and ROSAT observations of PKS 2126-158 for which results were never presented elsewhere,

Wolfgang Keil, H. -Thomas Janka, Ewald M&#34;uller

Two-dimensional hydrodynamical simulations of the deleptonization of a newly formed neutron star were performed. Driven by negative lepton fraction and entropy gradients, convection starts near the neutrinosphere about 20-30 ms after core bounce, but moves deeper into the protoneutron star, and after about one second the whole protoneutron star is convective

Jeffrey A. Willick, Stephane Courteau, S. M. Faber, David Burstein

This is the third in a series of papers in which we assemble and analyze a homogeneous catalog of peculiar velocity data. In Papers I and II, we described the Tully-Fisher (TF) redshift-distance samples that constitute the bulk of the catalog, and our methodology for obtaining mutually consistent TF calibrations for these samples. In this paper, we supply fu

S. Yu. Khlebnikov, I. I. Tkachev

We present results of fully non-linear calculations of decay of the inflaton interacting with another scalar field X. Combining numerical results for cosmologically interesting range of resonance parameter, q \leq 10^6, with analytical estimates, we extrapolate them to larger q. We find that scattering of X fluctuations off the Bose condensate is a very effi

Keith R. Dienes, Christopher Kolda, John March-Russell

The most general Lagrangian for a model with two U(1) gauge symmetries contains a renormalizable operator which mixes their gauge kinetic terms. Such kinetic mixing can be generated at arbitrarily high scales but will not be suppressed by large masses. In models whose supersymmetry (SUSY)-breaking hidden sectors contain U(1) gauge factors, we show that such

Pavel Etingof, David Kazhdan

In this paper we construct explicitly the quantization of Lie bialgebras of $\g$-valued functions on a punctured rational or elliptic curve, where $\g$ is a finite dimensional simple Lie algebra. by reducing the problem of quantization of the algebra of $\g$-valued functions on a curve with many punctures to the case of one puncture.

Peter Bantay

An analogue of the classical Frobenius-Schur indicator is introduced in order to distinguish between real and pseudo-real self-conjugate primary fields, and an explicit expression for this quantity is derived from the trace of the braiding operator.

Martin Reuter, Michael G. Schmidt, Christian Schubert

We investigate the usefulness of the &#34;string-inspired technique&#34; for gauge theory calculations in a constant external field background. Our approach is based on Strassler&#39;s worldline path integral approach to the Bern-Kosower formalism, and on the construction of worldline (super--) Green&#39;s functions incorporating external fields as well as i

Gillian Wilson, Ian Smail, Richard S. Ellis, Warrick J. Couch

We present deep two-colour photometry of two rich clusters at z=0.18, A665 and A1689. We use these data to construct number counts as a function of magnitude in the two fields. By combining these counts with similar observations from a large area field survey we subtract the field contamination statistically to produce luminosity functions for the two cluste

Stephen L. Adler

We give a model for composite quarks and leptons based on the semisimple gauge group SU(4), with the preons in the 10 representation; this choice of gauge gluon and preon multiplets is motivated by the possibility of embedding them in an N=6 supergravity multiplet. Hypercolor singlets are forbidden in the fermionic sector of this theory; we propose that SU(4

H. U. Boden

X.-S. Lin and Z. Wang recently made a conjecture concerning the integrality of the Taylor coefficients of the averaged Jones polynomial of algebraically split links. This question is related to a conjectural integrality result for the Ohtsuki invariants, which are rational topological invariants of homology 3-spheres derived from the quantum invariants of Wi

H. U. Boden

An invariant $μ_α(K)$ of fibred knots $K$ in a homology sphere is defined for each $α\in {\bold S}{\bold U}_n$ as follows. Since the knot is fibred, the knot complement is described by an element of the mapping class group, which induces an action on the variety of ${\bold S}{\bold U}_n$ representations of the surface group. Restricting attention to those re

Graham D. Kribs, I. Z. Rothstein

We place bounds on long-lived primordial relics using measurements of the diffuse gamma ray spectrum from EGRET and COMPTEL. Bounds are derived for both radiative and hadronic decays with stronger bounds applying for the latter decay mode. We present an exclusion plot in the relic density-lifetime plane that shows nontrivial dependence on the mass of the rel

Malte Henkel

A new set of infinitesimal transformations generalizing scale invariance for strongly anisotropic critical systems is considered. It is shown that such a generalization is possible if the anisotropy exponent θ=2/N, with N=1,2,3 ... Differential equations for the two-point function are derived and explicitly solved for all values of N. Known special cases are

James R. Chapman, Neil F. Johnson, V. Nikos Nicopoulos

A negatively charged quasi-two dimensional exciton ($X^-$) is solved exactly numerically in the presence of a uniform perpendicular B-field. Various quasi-two dimensional geometries are studied. The charge distribution of the $X^-$ parallel to the B-field is found to be crucial in determining the stability of the optically-active $X^-$ and hence its photolum

Piero Olla

The lift on a strongly non-spherical vesicle in a bounded shear flow, is studied in the case the membrane moves with a velocity, which is a linear function of the coordinates. The magnitude of the induced drift is calculated as a function of the axes lengths, of the distance from the wall, and of the ratio of the cell to the solvent viscosity. It appears tha

Takeo Inami, Hiroaki Kanno, Tatsuya Ueno, Chuan-Sheng Xiong

We investigate the structure of an infinite-dimensional symmetry of the four-dimensional Kähler WZW model, which is a possible extension of the two-dimensional WZW model. We consider the SL(2,R) group and, using the Gauss decomposition method, we derive a current algebra identified with a two-toroidal Lie algebra, a generalization of the affine Kac-Moody alg

Dany Page

It is generally considered that the neutron star cooling scenarios involving fast neutrino emission, from a kaon or pion condensate, quark matter, or the direct Urca process, require the presence of baryon pairing in the central core of the star to control the strong neutrino emission and produce surface temperatures compatible with observations. I show here

P. Stovicek, R. Twarock

A relationship between quantum flag and Grassmann manifolds is revealed. This enables a formal diagonalization of quantum positive matrices. The requirement that this diagonalization defines a homomorphism leads to a left \Uh -- module structure on the algebra generated by quantum antiholomorphic coordinate functions living on the flag manifold. The module i

F. Arias de Saavedra, G. Co&#39;, M. M. Renis

The proton momentum and density distributions of closed shell nuclei are calculated within a model treating short--range correlations up to first order in the cluster expansion. The validity of the model is verified by comparing the results obtained with purely scalar correlations with those produced by finite nuclei Fermi Hypernetted Chain calculations. Sta

A. Mengoni, T. Otsuka, T. Nakamura, M. Ishihara

The connection between the neutron halo observed in light neutron rich nuclei and the neutron radiative capture process is outlined. We show how nuclear structure information such as spectroscopic factors and external components of the radial wave function of loosely bound states can be derived from the neutron capture cross section. The link between the dir

N. Herrmann, FOPI Collaboration

An overview is given over recent measurements of flow and particle production in the energy range from 0.1 to 2AGeV. Excitation functions for the directed sideward and the azimuthally symmetric transverse flow are presented and show the importance of flow phenomena in this incident energy regime. Rapidity density distributions are indicative of a system size

Andrei Shuvaev

Matrix model approach to multicolor induced QCD based on the quenched momentum prescription is presented. It is shown that this model exhibits the reduction of spatial degrees of freedom: the partition function is determined by the solution of one dimensional quantum mechanical problem while the D-dimensional scalar field correlators coinside with the same t

Hilary Booth, Chris Radford

A reduction of the Dirac-Maxwell equations in the case of static cylindrical symmetry is performed. The behaviour of the resulting system of o.d.e.&#39;s is examined analytically and numerical solutions presented. There are two classes of solutions. The first type of solution is a Dirac field surrounding a charged &#34;wire&#34;. The Dirac field is highly lo

L. Faddeev, Antti J. Niemi

Using methods of high performance computing, we have found indications that knotlike structures appear as stable finite energy solitons in a realistic 3+1 dimensional model. We have explicitly simulated the unknot and trefoil configurations, and our results suggest that all torus knots appear as solitons. Our observations open new theoretical possibilities i

I. T. Drummond, R. R. Horgan, P. V. Landshoff, A. Rebhan

The pressure of a system in thermal equilibrium is expressed as a mass integral over a sum of thermal propagators. This allows a Dyson resummation and is used to demonstrate that potential infrared divergences are rendered harmless.

Nadja Kutz

We extend the notion of space shifts introduced by L. D. Faddeev and A. Yu. Volkov (Phys. Lett. B 315 (1993)) for certain quantum light cone lattice equations of sine-Gordon type at root of unity. As a result we obtain a compatibility equation for the roots of central elements within the algebra of observables (also called current algebra). The equation whic

John F. Donoghue, Alexey A. Petrov

We propose a QCD-based model for calculation of the non-perturbative corrections to the factorization approximation in the decays of heavy mesons. In the framework of the model, factorization in pseudoscalar transitions holds exactly at the leading order leaving the opportunity to calculate non-leading corrections consistently.

Jianwei Qiu, George Sterman

We review the extension of the factorization formalism for perturbative QCD to soft initial- and final-state scattering associated with hard processes in nuclei.

M. J. Musolf

The use of spin observables to study the semi-leptonic and non-leptonic weak interaction in atoms and nuclei is surveyed. In particular, the use of semi-leptonic neutral current scattering and atomic parity violation to search for physics beyond the Standard Model is reviewed. The status of nuclear parity violation as a probe of the weak N-N interaction is s

Luis Gonzalez-Mestres

If Lorentz invariance is only an approximate property of equations describing a sector of matter above some critical distance scale, the speed of light c will not necessarily be the only critical speed in vacuum. Superluminal sectors of matter may exist related to new degrees of freedom not yet discovered experimentally. The new particles would not be tachyo

Edmond L. Berger, Harry Contopanagos

We summarize our calculation of the total cross section for top quark production at hadron colliders within the context of perturbative quantum chromodynamics, including resummation of the effects of initial-state soft gluon radiation to all orders in the strong coupling strength.

Pran Nath, R. Arnowitt

A review is given of nucleon instability in SUSY models. The minimal SU(5) model is discussed in detail.

Matthias Neubert

Using the virial theorem of the heavy-quark effective theory, we show that the mixing of the operator for the heavy-quark kinetic energy with the identity operator is forbidden at the one-loop order by Lorentz invariance. This explains why such a mixing was not observed in several one-loop calculations using regularization schemes with a Lorentz-invariant UV

J. Ellis, J. Lopez, D. Nanopoulos

We propose an analysis of LEP constraints on radiative neutralino decays into a light gravitino, based on the plane of the Higgs mixing parameter mu and the SU(2) gaugino mass M_2. The preliminary LEP 2W constraints in the (mu, M_2) plane are considerably stronger than for supersymmetric models in which the lightest neutralino is stable. A significant portio

M. L. Mangano, G. Altarelli, N. Di Bartolomeo, F. Feruglio

We review the main features of the leptophobic-Z&#39; phenomenology, commenting on the prospects of these models after the recent experimental results on R_c, R_b and after the recent theoretical analyses of jet production at the Tevatron.

L. Avdeev, J. Fleischer, M. Yu. Kalmykov, M. Tentyukov

A method to calculate two-loop self-energy diagrams of the Standard Model is demonstrated. A direct physical application is the calculation of the two-loop electroweak contribution to the anomalous magnetic moment of the muon ${1/2}(g-2)_μ$. Presently we confine ourselves to a ``toy&#39;&#39; model with only $μ$, $γ$ and a scalar particle (Higgs). The algori

G. V. Dass, K. V. L. Sarma

We estimate the product of the relative strength of the $ΔB = -ΔQ$ amplitude in the decay $B_d^0 \rightarrow D^{*} \ell \bar ν_{\ell }$ and the width-difference parameter $y$. For this we have used the data on time-dependence of $B_{d}^0\bar B_{d}^0$ oscillations in Z decays and the fraction of like-sign dilepton events at the $Υ(4S)$.

Mou Roy

Neutrino Oscillations in the presence of strong gravitational fields are studied specifically for Majorana neutrinos. We look at ultra high energy neutrinos $(\sim 1$ PeV) emanating from Active Galactic Nuclei (AGN). Fluxes of different flavor neutrinos are estimated and probabilities for different neutrino transitions calculated.

O. Borisenko, M. Faber, G. Zinovjev, K. Petrov

The deconfinement phase transition is studied in the ensemble canonical with respect to triality. Since this ensemble implies a projection to the zero triality sector of the theory we introduce a quantity which is insensitive to $Z(N_c)$ symmetry but can reveal a critical behaviour in the theory with dynamical quarks. Further, we argue that in the canonical

S. Aoki, K. Nagai

We investigate an original domain-wall model in 4+1 dimensions numerically in the presence of U(1) dynamical gauge field only in an extra dimension, corresponding to a weak coupling limit of 4-dimensional physical gauge coupling. Using a quenched approximation we carry out numerical simulation for this model at $β_{s} (= 1 / g^{2}_{s}) =$ 0.29 (``symmetric&#

Peter Anninos, Joan Masso, Edward Seidel, Wai-Mo Suen

The dynamics of gravitational waves is investigated in full 3+1 dimensional numerical relativity, emphasizing the difficulties that one might encounter in numerical evolutions, particularly those arising from non-linearities and gauge degrees of freedom. Using gravitational waves with amplitudes low enough that one has a good understanding of the physics inv

Samuel L. Braunstein

We present a toy model for growing wormholes as a model of effective low-energy topology changes. We study the propagation of quantum fields on a $1+1$ spacetime analogous to the trouser-leg topology change. A low-energy effective topology change is produced by a physical model which corresponds to a barrier smoothly changing the tunneling probability betwee

Akio Hosoya, Ichiro Oda

We study a black hole radiation inside the apparent horizon in quantum gravity. First we perform a canonical quantization for spherically symmetric geometry where one of the spatial coordinates is dealt as the time variable since we would like to consider the interior region of a black hole. Next this rather general formalism is applied for a specific model

A. D. Y. Cheng, P. D. D&#39;Eath

We take the general quantum constraints of N=1 supergravity in the special case of a Bianchi metric, with gravitino fields constant in the invariant basis. We construct the most general possible wave function which solves the Lorentz constraints and study the supersymmetry constraints in the Bianchi Class A Models. For the Bianchi-IX cases, both the Hartle-H

Theodore C. Quinn, Robert M. Wald

The problem of determining the electromagnetic and gravitational ``self-force&#39;&#39; on a particle in a curved spacetime is investigated using an axiomatic approach. In the electromagnetic case, our key postulate is a ``comparison axiom&#39;&#39;, which states that whenever two particles of the same charge $e$ have the same magnitude of acceleration, the

P. Neu, A. Heuer

A quantum mechanical treatment of an asymmetric double-well potential (DWP) interacting with a heat bath is presented for circumstances where the contribution of higher vibrational levels to the relaxation dynamics cannot be excluded from consideration. The deep quantum limit characterized by a discrete energy spectrum near the barrier top is considered. The

V. V. Flambaum, F. M. Izrailev

New method is developed for calculation of single-particle occupation numbers in finite Fermi systems of interacting particles. It is more accurate than the canonical distribution method and gives the Fermi-Dirac distribution in the limit of large number of particles. It is shown that statistical effects of the interaction are absorbed by an increase of the

Andreas Rudinger, Frederic Piechon

We consider the Harper model which describes two dimensional Bloch electrons in a magnetic field. For irrational flux through the unit-cell the corresponding energy spectrum is known to be a Cantor set with multifractal properties. In order to relate the maximal and minimal fractal dimension of the spectrum of Harper&#39;s equation to the irrational number i

G. B. Lesovik, A. L. Fauchère, G. Blatter

A general formula for the current through a disordered normal--superconducting junction is derived, which is valid at finite temperature and includes the full voltage dependence. The result depends on a multichannel scattering matrix, which describes elastic scattering in the normal region, and accounts for the Andreev scattering at the NS interface. The sym

Guenter Sigl, Angela Olinto, Karsten Jedamzik

We give an improved estimate of primordial magnetic fields generated during cosmological first order phase transitions. We examine the charge distribution at the nucleated bubble wall and its dynamics. We consider instabilities on the bubble walls developing during the phase transition. It is found that damping of these instabilities due to viscosity and hea

Jeffrey A. Willick

Six of the principal galaxy distance indicators are discussed: Cepheid variables, the Tully-Fisher relation, the Dn-sigma relation, Surface Brightness Fluctuations, Brightest Cluster Galaxies, and Type Ia Supernovae. The role they play in peculiar velocity surveys and Hubble constant determination is emphasized. Past, present, and future efforts at construct

E. Dwek

Using data obtained by the DIRBE and FIRAS instruments on the COBE spacecraft we present the mean 3.5-1000 um dust spectrum from the high latitude cirrus clouds. These data represent the most comprehensive wavelength coverage of dust emission, and first strong evidence for the presence of PAHs in cirrus. The COBE data are well fit with a dust model consistin

R. A. Battye

We consider the effects of photon diffusion on the small-angle microwave background anisotropies due to active source models. We find that fluctuations created just before the time of last scattering allow anisotropy to be created on scales much smaller than allowed by standard Silk damping. Using simple models for string and texture structure functions as e

R. A. Battye, E. P. S. Shellard

The next generation of gravitational wave detectors holds out the prospect of detecting a stochastic gravitational background generated in the very early universe. In this article, we review the various cosmological processes which can lead to such a background, including quantum fluctuations during inflation, bubble collisions in a first-order phase transit

A. Del Popolo, M. Gambera, V. Antonuccio-Delogu

We solve numerically the equations of motion for the collapse of a shell of baryonic matter falling into the central regions of a cluster of galaxies, taking into account of the presence of the substructure inducing dynamical friction. The evolution of the expansion parameter a(t) of the perturbation is calculated in spherical systems. The effect of dynamica

P. Dubath, C. J. Grillmair

We present internal velocity dispersion determinations from high-resolution spectroscopic observations of a sample of nine globular clusters in M31. Comprehensive numerical simulations are used to show that the typical uncertainty of our velocity dispersion measurements is about 5%. Using these new velocity dispersions together with structural parameters der

Georg Raffelt, Thomas Strobel

Nucleon spin fluctuations in a dense medium reduce the ``naive&#39;&#39; values of weak interaction rates (neutrino opacities, neutrino emissivities). We extend previous studies of this effect to the degenerate case which is appropriate for neutron stars a few ten seconds after formation. If neutron-neutron interactions by a one-pion exchange potential are t

A. Burkert

The amount of dark matter in the four galactic dwarf spheroidals with large mass-to-light ratios is investigated. Sextans has a cut-off radius which is equal to the expected tidal radius, assuming a high mass-to-light ratio. This satellite very likely is dark matter dominated. Carina, Ursa Minor and Draco, on the other hand, cannot contain a dominating dark

H. C. Rosu

If the dynamic instability of microtubules follows a gamma distribution then one can associate to it a Cantor set

Ulf-G. Meißner

I review some basic facts about the chiral limit of QCD. This allows to formulate an effective field theory below the chiral symmetry breaking scale, chiral perturbation theory (CHPT). I show that for threshold reactions, the spectrum of QCD is most economically encoded in a set of coupling constants of operators of higher chiral dimension. A consistent sche

Julio F. Navarro

High-resolution N--body simulations show a remarkable similarity in the structure of dark matter halos formed through dissipationless hierarchical clustering. Independent of halo mass, power spectrum, and cosmological parameters, the density profiles of dark halos can be accurately fit by scaling a simple two-parameter profile. The two parameters of the fit,

Peter Arnold, Yan Zhang

We propose numerical simulations of the Ashkin-Teller model as a foil for theoretical techniques for studying very weakly first-order phase transitions in three dimensions. The Ashkin-Teller model is a simple two-spin model whose parameters can be adjusted so that it has an arbitrarily weakly first-order phase transition. In this limit, there are quantities

Valter Moretti, Devis Iellici

The optical manifold method to compute the one-loop effective action in a static space-time is extended from the massless scalar field to the Maxwell field in any Feynman-like covariant gauge. The method is applied to the case of the Rindler space obtaining the same results as the point-splitting procedure. The result is free from Kabat&#39;s surface terms w