June 1997 arXiv papers — page 2

Edward Farhi, Sam Gutmann

Many interesting computational problems can be reformulated in terms of decision trees. A natural classical algorithm is to then run a random walk on the tree, starting at the root, to see if the tree contains a node n levels from the root. We devise a quantum mechanical algorithm that evolves a state, initially localized at the root, through the tree. We pr

B. Holdom

We question whether the canonical estimate of a strong coupling, α\approx 4π, is always appropriate for dynamical symmetry breaking. Our discussion is motivated by the success of naive quark models in describing low energy QCD.

Nickolay Y. Gnedin

I apply the well controlled Hydro-PM approximation of Gnedin & Hui to model the column density distribution of the Lyman-alpha forest for 25 different flat cosmological scenarios, including variants of the standard CDM, tilted CDM, CDM with a cosmological constant, and CHDM models. I show that within the accuracy of the HPM approximation the slope of the col

Yoshinori Tutui, Yoshiaki Sofue

We investigate effects of galaxy-galaxy interaction on the Tully-Fisher relation. The HI linewidth in interacting galaxies is significantly broader than the CO linewidth, and the HI to CO linewidth ratio is proportional to the strength of interaction. This provides different distances to galaxies measured by the Tully-Fisher relation with the CO and HI linew

E. Church, I. Stancu, G. J. VanDalen, R. A. Johnson

This Letter of Intent to the Fermilab Program Advisory Committee describes a search for neutrino oscillations at the Fermilab booster. It is motivated by the LSND observation of nu_mu -> nu_e appearance. The booster neutrino experiment (BooNE) will be capable of observing both nu_mu -> nu_e appearance and nu_mu disappearance. In addition, the experiment will

Kiam Choo, T. C. A. Molteno, Stephen W. Morris

Mixtures of granular media often exhibit size segregation along the axis of a partially-filled, horizontal, rotating cylinder. Previous experiments have observed axial bands of segregation that grow from concentration fluctuations and merge in a manner analogous to spinodal decomposition. We have observed that a new dynamical state precedes this effect in ce

W. Poirier, D. Mailly, M. Sanquer

We observe an inversion of the low temperature dependence for the conductivity of doped GaAs by application of a magnetic field. This inversion happens when Wct = 1, as predicted by Houghton (PRB25, 2196, 1982) for the correction to conductivity due to screened Coulomb repulsion in the diffusive regime. This correction follows the oscillating behavior of the

V. Antonelli, V. Ivanchenko, E. Kuraev, V. Laliena

We consider some radiative corrections to the lowest order annihilation diagram for the orthopositronium decay rate. The insertion of the renormalized vertex correction in the annihilation graph gives $1.6283 (α/π)^2 Γ_0$. We compute also the contribution of the square of the lowest order annihilation amplitude, which turns out to be $0.1702 (α/π)^2 Γ_0$. Fi

Andrei Afanasev, Carl E. Carlson, Christian Wahlquist

We calculate polarization asymmetries in photoproduction of high transverse momentum mesons, focusing on charged pions, considering the direct, fragmentation, and resolved photon processes. The results at very high meson momentum measure the polarized quark distributions and are sensitive to differences among the existing models. The results at moderate meso

V. M. Loktev, S. G. Sharapov

This article gives a contemporary and to some extent pedagogical review of the current theoretical understanding of the formation of the superconducting state in metallic systems with a variable density of carriers. We make an attempt to describe the crossover from the Bose-Einstein condensation type (small densities) to the Bardeen-Cooper-Schrieffer one (la

William D. Walker, J. Dual

The near-field Lienard-Wiechert potential solution of a longitudinally oscillating electrical field produced by an oscillating charge is presented, and the results are compared to the R. P. Feynman multipole far-field solution. The results indicate that the phase speed of a longitudinally oscillating electrical field is much faster than the speed of light in

L. Ciotti, J. P. Ostriker

We present a new class of solutions for the gas flows in elliptical galaxies containing massive central black holes (BH). Modified King model galaxies are assumed. Two source terms operate: mass loss from evolving stars, and a secularly declining heating by SNIa. Relevant atomic physical processes are modeled in detail. Like the previous models investigated

J. Dennett-Thorpe, A. H. Bridle, P. A. G. Scheuer, R. A. Laing

The less depolarized lobe of a radio source is generally the lobe containing the jet (Laing-Garrington correlation) but the less depolarized lobe is also generally that with the flatter radio spectrum (Liu-Pooley correlation). Both effects are strong; taken together they would imply a correlation between jet side and lobe spectral index, i.e. between an orie

S. E. Parkhomenko

Poisson-Lie T-duality in N=2 superconformal WZNW models on the real Lie groups is considered. It is shown that Poisson-Lie T-duality is governed by the complexifications of the corresponding real groups endowed with Semenov-Tian-Shansky symplectic forms, i.e. Heisenberg doubles. Complex Heisenberg doubles are used to define on the group manifolds of the N=2

P. Giacconi, F. Maltoni, R. Soldati

It is shown that the scattering amplitude for contact-interacting anyons does exhibit a genuine non-perturbative sector. This means that the corresponding perturbative field theoretical formulation, based on the {\it 2+1} non-relativistic Chern-Simons gauge model coupled to self-interacting complex scalar field, is not generally able to reproduce, order by o

Ruy A. H. Farias, Erasmo Recami

In this review-article, we discuss the consequences of the introduction of a quantum of time tau_0 in the formalism of non-relativistic quantum mechanics (QM) by referring ourselves in particular to the theory of the "chronon" as proposed by P.Caldirola. Such an interesting "finite difference" theory, forwards --at the classical level-- a sol

Sandeep K. Joshi, A. M. Jayannavar

A numerical study of the statistics of transmission ($t$) and reflection ($r$) of quasi-particles from a one-dimensional disordered lasing or amplifying medium is presented. The amplification is introduced via a uniform imaginary part in the site energies in the disordered segment of the single-band tight binding model. It is shown that $t$ is a non-self-ave

Craig A. Tracy, Harold Widom

The focus of this survey paper is on the distribution function for the largest eigenvalue in the finite N Gaussian ensembles (GOE,GUE,GSE) in the edge scaling limit of N->infinity. These limiting distribution functions are expressible in terms of a particular Painleve II function. Comparisons are made with finite N simulations as well as a discussion of the

Kiyoung Kim

Using classical statistics, Schrodinger equation in quantum mechanics is derived from complex space model. Phase-space probability amplitude, that can be defined on classical point of view, has connections to probability amplitude in internal space and to wave function in quantum mechanics. In addition, the physical entity of wave function in quantum mechani

D. T. Barclay

The supersymmetric-WKB series is shown to be such that the SWKB quantisation condition has corrections in powers of h^2 only and with explicit overall factors of E. The results also suggest more efficient methods of calculating the corrections.

Boucif Abdesselam, Ranabir Chakrabarti

We consider the reflection equation algebra for a finite dimensional R-matrix for the $(h,w)$-deformed Heisenberg algebra ${\cal U}_{h,w}(h(4))$. A representation of the reflection matrix $K$ is constructed using the matrix generators $L^{(\pm)}$ of the ${\cal U}_{h,w}(h(4))$ algebra. A series of representations of the K-matrix then may be generated by using

G. F. Bertsch, K. Yabana

We discuss the calculation of collective excitations in atomic clusters using the time-dependent local density approximation. In principle there are many formulations of the TDLDA, but we have found that a particularly efficient method for large clusters is to use a coordinate space mesh and the algorithms for the operators and the evolution equations that h

T. Hezel, R. Rossmanith, B. Krevet, H. O. Moser

In this paper the concept and the first successful tests towards constructing a superconductive micro-undulator with a period length of 3.8 mm are described. The structures were built with a commercially available NbTi wire. A full 100 periods prototype is now under construction.

Sergiu I. Vacaru

The monograph gives a general geometric background of the theory of field interactions, strings and diffusion processes on spaces, superspaces and isospaces with higher order anisotropy and inhomogenity. Our approach proceeds by developing the concept of higher order anisotropic superspace which unify the logical and mathematical aspects of modern Kaluza-Kle

A. B. Balantekin, C. A. Bertulani, M. S. Hussein

We study the combined effects of vacuum polarization, relativity, Bremsstrahlung, and atomic polarization in nuclear reactions of astrophysical interest. It is shown that these effects do not solve the longstanding differences between the experimental data of astrophysical nuclear reactions at very low energies and the theoretical calculations which aim to i

Amand Faessler, A. J. Buchmann, M. I. Krivoruchenko

The effect of narrow dibaryon resonances to nuclear matter and structure of neutron stars is investigated in the mean-field theory (MFT) and in the relativistic Hartree approximation (RHA). The existence of massive neutron stars imposes constraints to the coupling constants of the omega- and sigma-mesons with dibaryons. We conclude that the experimental cand

A. Dumitru, C. Spieles, H. Stoecker, C. Greiner

We discuss the evolution of the mixed phase at RHIC and SPS within boostinvariant hydrodynamics. In addition to the hydrodynamical expansion, we also consider evaporation of particles off the surface of the fluid. The back-reaction of the evaporation process on the dynamics of the fluid shortens the lifetime of the mixed phase. In our model this lifetime of

A. Kievsky, S. Rosati, M. Viviani, C. R. Brune

The three-nucleon system is studied at energies a few hundred keV above the N-d threshold. Measurements of the tensor analyzing powers $T_{20}$ and $T_{21}$ for p-d elastic scattering at $E_{c.m.}=432$ keV are presented together with the corresponding theoretical predictions. The calculations are extended to very low energies since they are useful for extrac

Nigel Boston, David T. Ose

We examine which representations of the absolute Galois group of a field of finite characteristic with image over a finite field of the same characteristic may be constructed by the Galois group's action on the division points of an appropriate Drinfeld module.

Fernando Quevedo

This is a general introduction to duality in field theories. The existence and breaking of global symmetries is used as a guideline to systematically prove duality between different field theories. Systems discussed include abelian and non-abelian T-duality in string theory, abelian and nonabelian bosonization, and duality for massless and massive antisymmet

James T. Wheeler

Scale invariance provides a principled reason for the physical importance of Hilbert space, the Virasoro algebra, the string mode expansion, canonical commutators and Schroedinger evolution of states, independent of the assumptions of string theory and quantum theory. The usual properties of dimensionful fields imply an infinite, projective tower of conforma

M. S. Cunha, H. R. Christiansen, C. A. S. Almeida

By imposing self-duality conditions, we obtain the explicit form in which gauge theories spontaneously breakdown in the Bogomol'nyi limit. In this context, we reconsider the Abelian Higgs, Chern-Simons Higgs and Maxwell-Chern-Simons Higgs models. On the same footing, we find a topological Higgs potential for a Maxwell-Chern-Simons extended theory present

Paul Federbush

Continuing the thrust of our recent work, but with an important new idea, we find a cut-off regularization of the determinant of a scalar particle in a classical Euclidean gravitational field. The field is assumed asymptotically flat, and the regularization is diffeomorphism-invariant under coordinate changes that are the identity at infinity. The scalar fie

Roberto Emparan

We derive the low energy absorption cross section of minimal scalars for a very generic class of geometries, that includes, among others, black holes, strings, $p$-branes, as well as intersecting brane configurations. The scalar field can be absorbed across a regular surface (a horizon) of finite area, or across a zero area throat, which may be singular or r

C. R. Fernández-Pousa, J. L. Miramontes

The semi-classical spectrum of the Homogeneous sine-Gordon theories associated with an arbitrary compact simple Lie group G is obtained and shown to be entirely given by solitons. These theories describe quantum integrable massive perturbations of Gepner's G-parafermions whose classical equations-of-motion are non-abelian affine Toda equations. One-solit

N. P. Chitaia, S. A. Gogilidze, Yu. S. Surovtsev

In the generalized Hamiltonian formalism by Dirac, the method of constructing the generator of local-symmetry transformations for systems with first- and second-class constraints (without restrictions on the algebra of constraints) is obtained from the requirement for them to map the solutions of the Hamiltonian equations of motion into the solutions of the

Massimo Giovannini

A magnetic field, coherent over the horizon size at the decoupling and strong enough to rotate the polarization plane of the CMBR, can be generated from the electromagnetic vacuum fluctuations amplified by the space-time evolution of the dilaton coupling. The possible relevance of this result for superstring inspired cosmological models is discussed. Particu

Robert Brout

The mathematical apparatus of non commutative geometry and operator algebras which Connes has brought to bear to construct a rational scheme for the internal symmetries of the standard model is presented from the physicist's point of view. Gauge symmetry, anomaly freedom, conservation of electric charge, parity violation and charge conjugation all play a

R. K. Ellis, Sinisa Veseli

We describe an alternative approach to the prediction of W and Z transverse momentum distributions based on an extended version of the DDT formula. The resummation of large logarithms, mandatory at small qT, is performed in qT-space, rather than in the impact parameter b. The leading, next-to-leading and next-to-next-to-leading towers of logarithms are ident

C. Spieles, L. Gerland, N. Hammon, M. Bleicher

A study of secondary Drell-Yan production in nuclear collisions is presented for SPS energies. In addition to the lepton pairs produced in the initial collisions of the projectile and target nucleons, we consider the potentially high dilepton yield from hard valence antiquarks in produced mesons and antibaryons. We calculate the secondary Drell-Yan contribut

J. D. Bjorken

This summary of the 2nd International Conference on B Physics and CP Violation (Honolulu, 24--27 March, 1997) contains, in addition to what is implied in the title, some extended remarks on the limitations of theory as well as speculations regarding nonperturbative enhancement of decay modes of the class b -> s + charmless hadrons.

E. Bagan, M. Lavelle, D. McMullan, B. Fiol

This talk reports on work aimed at improving our understanding of charged states in gauge theories.Emphasis is placed on different ways of implementingthe gauge invariance of physical states. QED perturbative calculations are used to stress that gauge invariance is not enough: only a subset of such states have a direct physical significance. In QCD a non-per

She-Sheng Xue

In a possible $SU_L(2)$ lattice chiral gauge theory with a large multifermion coupling, we try to further clarify the threshold phenomenon: the possibility that the right-handed three-fermion state turns into the virtual states of its constituents (free chiral fermions) in the low-energy limit. Provided this phenomenon occurs, we discuss the chiral gauge cou

H. S. Kambara

We present the result of direct leptoquark searches based on 110 pb-1 of integrated luminosity collected by the Collider Detector at Fermilab during the 1992-93 and 1994-95 Tevatron runs at \sqrt{s}=1.8 TeV. We present upper limits on the production cross sections as a function of the leptoquark mass. Using the NLO calculation of the leptoquark-pair producti

S. Ansoldi, A. Aurilia, R. Balbinot, E. Spallucci

Following a minisuperspace approach to the dynamics of a spherically symmetric shell, a reduced Lagrangian for the radial degree of freedom is derived directly from the Einstein-Hilbert action. The key feature of this new Lagrangian is its invariance under time reparametrization. Indeed, all classical and quantum dynamics is encoded in the Hamiltonian constr

W. Kramer, U. Semmelmann, G. Weingart

In a previous article we proved a lower bound for the spectrum of the Dirac operator on quaternionic Kaehler manifolds. In the present article we study the limiting case, i. e. manifolds where the lower bound is attained as an eigenvalue. We give an equivalent formulation in terms of a quaternionic Killing equation and show that the only symmetric quaternion

Christian Baer

We show that for a suitable class of ``Dirac-like'' operators there holds a Gluing Theorem for connected sums. More precisely, if $M_1$ and $M_2$ are closed Riemannian manifolds of dimension $n\ge 3$ together with such operators, then the connected sum $M_1 # M_2$ can be given a Riemannian metric such that the spectrum of its associated operator is c

A. K. Hassan, L. A. Pardi, G. B. Martins, G. Cao

High-Field Electron Spin Resonance measurements were made on powder samples of Cu_{1-x}Zn_{x}GeO_{3} (x=0.00, 0.01, 0.02, 0.03 and 0.05) at different frequencies (95, 110, 190, 220, 330 and 440 GHz) at low temperatures. The spectra of the doped samples show resonances whose positions are dependent on Zn concentration, frequency and temperature. The analysis

M. Yamashiro, Y. Tanaka, S. Kashiwaya

A theory for tunneling spectroscopy in normal metal /insulator/triplet superconductor junction is presented. We assume two kinds of non-unitary triplet superconducting states which are the most promising states for Sr$_{2}$RuO$_{4}$. The calculated conductance spectra showzero-bias peaks as well as gap structures. The existences of residual components in the

Benny Davidovich, V. Zevin

We consider the Hubbard model with a magnetic Anderson impurity coupled to a lattice site. In the case of infinite dimensions, one-particle correlations of the impurity electron are described by the effective Hamiltonian of the two-impurity system. One of the impurities interacts with a bath of free electrons and represents the Hubbard lattice, and the other

Mario Nicodemi, Antonio Coniglio

We study microscopic and macroscopic dynamical properties of a frustrated lattice gas, strictly related to usual spin glasses, showing the violation of Stokes-Einstein law. The glassy behaviors are analyzed and related with experimental results in glass former systems.

K. Binder, M. Mueller, F. Schmid, A. Werner

The structure of polymer coils near interfaces between coexisting phases of symmetrical polymer mixtures (AB) is discussed, as well as the structure of symmetric diblock copolymers of the same chain length N adsorbed at the interface. The problem is studied by Monte Carlo simulations of the bond fluctuation model on the simple cubic lattice, using massively

Leonid B. Litinskii

A dynamic system, which is used in the neural network theory, Ising spin glasses and factor analysis, has been investigated. The properties of the connection matrix, which guarantee the coincidence of the set of the fixed points of the dynamic system with the set of the local minima of the energy functional, have been determined. The influence of the connect

Ph. Ghosez, X. Gonze, R. W. Godby

The polarization-dependence of the exchange-correlation (XC) energy functional of periodic insulators within Kohn-Sham (KS) density-functional theory requires a ${\cal O} (1/q^2)$ divergence in the XC kernel for small vectors q. This behaviour, exemplified for a one-dimensional model semiconductor, is also observed when an insulator happens to be described a

Claudio Donati, Jack F. Douglas, Walter Kob, Steven J. Plimpton

A large-scale molecular dynamics simulation is performed on a glass-forming Lennard-Jones mixture to determine the nature of dynamical heterogeneities which arise in this model fragile liquid. We observe that the most mobile particles exhibit a cooperative motion in the form of string-like paths (``strings'') whose mean length and radius of gyration

Seiji Miyashita, Keiji Saito, Hans De Raedt

How nanoscale uniaxial magnets respond to an alternating field is studied by direct numerical calculation. A nontrivial oscillation of the magnetization is found, which is analyzed in terms of the non-adiabatic transition due to the time dependent field. A new method to estimate the tunneling gap of the magnet is proposed.

Kan Chen, C. Jayaprakash

We present the results of a Wilson Renormalization Group study of the single-impurity Kondo and Anderson models in a system with a gap in the conduction electron spectrum. The behavior of the impurity susceptibility and the zero-frequency response function, $T<<S_z; S_z>>$ are discussed in the cases with and without particle-hole symmetry. In addition, for t

D. R. Kulkarni, A. S. Pandya, J. C. Parikh

A hybrid approach, incorporating concepts of nonlinear dynamics in artificial neural networks (ANN), is proposed to model time series generated by complex dynamic systems. We introduce well known features used in the study of dynamic systems - time delay $τ$ and embedding dimension $d$ - for ANN modelling of time series. These features provide a theoretical

Scott M. Zoldi, Henry S. Greenside

In a recent Letter, Hunt and Ott argued that SHORT-period unstable periodic orbits (UPOs) would be the invariant sets associated with a chaotic attractor that are most likely to optimize the time average of some smooth scalar performance function. In this Comment, we show that their conclusion does not hold generally and that optimal time averages may specif

C. J. A. P. Martins, E. P. S. Shellard

We use a simple analytic model for the evolution of currents in superconducting strings to estimate the strength of the `seed&#39; magnetic fields generated by these strings. This model is an extension of the evolution model of Martins and Shellard depending on a parameter $f$ which characterizes the importance of equilibration process in the evolution of th

Ilaria Musella, Giampaolo Piotto, Massimo Capaccioli

We extended to the R and I bands the light curve coverage for 8 Cepheids already studied in B and V by Capaccioli et al [AJ, 103, 1151 (1992)]. Sixteen additional Cepheid candidates have been identified and preliminary periods are proposed. The new Cepheids allow the period-luminosity relation to be extended one magnitude fainter. Apparent B, V, R, and I dis

Sukyoung Yi

The UV upturn in giant elliptical galaxies (gEs) implies significant corrections to the model-predicted optical colors of distant galaxies. However, since the origin of the UV upturn is still not clear, observers often use models that may not be acceptable. We show that &#34;the HB hypothesis&#34; of Yi et al. (1997) that explains most of the empirical const

I. V. Moskalenko, E. Jourdain

The region of the Galactic center contains several sources which demonstrate their activity at various wavelengths and particularly above several hundred keV. Escape of positrons from such a source or several sources into the interstellar medium, where they slow down and annihilate, can account for the 511 keV narrow line observed from this direction. 1E 174

A. Kogut

Cross-correlation of the DIRBE 100 micron survey with previously published H-alpha maps tests correlations between far-infrared dust and the warm ionized interstellar medium in different regions of the sky. A 10 x 12 deg patch at Galactic latitude b = -21 shows a correlation slope a_0 = 0.85 +/- 0.44 Rayleighs / MJy sr significant at 97% confidence. A set of

J. L. Sanz, E. Martinez-Gonzalez, N. Benitez

Correlations between the magnification or polarization of background sources, induced by gravitational lensing due to the large-scale structure, and the positions of foreground galaxies are investigated. We found that their amplitude is enhanced with respect to correlations for a single population. We analize the dependence of the correlations with the densi

P. Crane, J. Vernet

Deep U-band FOC images of the nuclear region of NGC6251 have revealed a region of extended emission which is most probably radiation scattered from a continuum source in the nucleus. This radiation lies interior to a dust ring, is nearly perpendicular to the radio jet axis, and is seen primarily in the FOC U and b filters. The extension has a low observed po

Fabrizio Brighenti, William G. Mathews

We describe the evolution of hot interstellar gas in a family of low luminosity elliptical galaxies all having $M_B = -20$ but with different degrees of flattening (E0, E2, and E6) caused by rotation. The interstellar gas is furnished by stellar mass loss. The soft X-ray luminosity Lx of the hot interstellar gas after 15 Gyrs decreases dramatically with gala

F. Combes, J-F. Becquaert

We present CO(1-0) and CO(2-1) observations of the two nearly face-on galaxies NGC 628 and NGC 3938, in particular cuts along the major and minor axis. The contribution of the beam-smeared in-plane velocity gradients to the observed velocity width is quite small in the outer parts of the galaxies. This allows us to derive the velocity dispersion of the molec

F. Combes, T. Wiklind

We report the detection of the H_2O molecule in absorption at a redshift z = 0.68466 in front of the gravitationally lensed quasar B0218+357. We detect the fundamental transition of ortho-water at 556.93 GHz (redshifted to 330.59 GHz). The line is highly optically thick and relatively wide (15 km/s FWHM), with a profile that is similar to that of the previou

F. A. Ringwald, T. Naylor

Images taken in 1.3&#34; seeing show that a claimed hibernating nova, Candidate 5 shown in a Sky & Telescope Newswire item, is found to be a visual binary, with a 1.1&#34; separation between components. Spectra reveal the components to be emission-line M0 and K7 stars.

F. A. Ringwald, W. R. J. Rolleston, R. A. Saffer, J. R. Thorstensen

PG 1002+506 is found to be a Be star, one of two so far found by the Palomar-Green survey. Its spectrum is classified as a B5 +/- 1 Ve, with Teff = 14,900 +/- 1200, log g = 4.2 +/- 0.2, and v sin i = 340 +/- 50 km/s. At b = +51 degrees, its height above the Galactic plane would therefore be Z = +10.8 kpc, putting this apparently young, rapidly rotating star

I. Bigi, R. David Dikeman, N. Uraltsev

We present an extended discussion of the previously noted possibility to extract |V_{ub}| from an analysis of the hadronic recoil mass spectrum in B->X_u l nu decays. Invariant mass spectra containing perturbative as well as nonperturbative corrections are given; their shape is manifestly sensitive to the three basic quantities mu_pi^2, m_b, and alpha_s$, wh

Ola Tornkvist, Antonio Riotto

Solitons in extensions of the Standard Model can serve as localized sources of CP violation. Depending on their stability properties, they may serve either to create or to deplete the baryon asymmetry. The conditions for existence of a particular soliton candidate, the membrane solution of the two-Higgs model, are presented. In the generic case, investigated

Victor M. Yakovenko, Hsi-Sheng Goan

We study edge and bulk open-orbit electron states in a quasi-one-dimensional (Q1D) metal subject to a magnetic field. For both types of the states, the energy spectrum near the Fermi energy consists of two terms. One term has a continuous dependence on the momentum along the chains, whereas the other term is quantized discretely. The discrete energy spectrum

Esko Keski-Vakkuri, Per Kraus

We study the effective actions of various brane configurations in Matrix theory. Starting from the 0+1 dimensional quantum mechanics, we replace coordinate matrices by covariant derivatives in the large N limit, thereby obtaining effective field theories on the brane world volumes. Even for noncompact branes, these effective theories are of Yang-Mills type,

Andrew Strominger

The universal hypermultiplet arises as a subsector of every Calabi-Yau compactification of M-theory or Type II string theory. Classically its moduli space is the quaternionic space $SU(2,1)/U(2)$. We show that this moduli space receives a one-loop correction proportional to the Euler character of the Calabi-Yau, which can locally be absorbed by a certain con

Volker Koch

This article is an attempt to a pedagogical introduction and review into the elementary concepts of chiral symmetry in nuclear physics. Effective chiral models such as the linear and nonlinear sigma model will be discussed as well as the essential ideas of chiral perturbation theory. Some applications to the physics of ultrarelativistic heavy ion collisions

V. P. Gudkov, K. Kubodera

The existing experimental evidence on the vector and axial-vector coupling constants, $G_V$ and $G_A$, for neutron $β$-decay exhibits two prominent problems: (i) the unitarity for the first row of the CKM matrix seems violated; (ii) one obtains different values of $G_A/G_V$ according to whether one uses as input the neutron lifetime or neutron-decay correlat

Isabel Campos

The properties of the Confinement-Higgs phase transition in the SU(2)-Higgs model with fixed modulus are investigated. We show that the system exhibits a transient behavior up to L=24 along which the order of the phase transition cannot be discerned. To get stronger conclusions about this point, without going to prohibitive large lattice sizes, we have intro

A. Amici, P. Thalmeier

We present a microscopic theory for the low temperature metamagnetic phase diagram of HoNi_2B_2C that agrees well with experiments.For the same model we determined the zero field ground state as a function of temperature and find the $c$-axis commensurate to incommensurate transition in the expected temperature range. The complex behaviour of the system orig

E. Martinec

We reinterpret N=(2,1) strings as describing the continuum limit of matrix theory with all spatial dimensions compactified. Thus they may characterize the full set of degrees of freedom needed to formulate the theory.

H. J. Boonstra, B. Peeters, K. Skenderis

We consider a series of duality transformations that leads to a constant shift in the harmonic functions appearing in the description of a configuration of branes. This way, for several intersections of branes, we can relate the original brane configuration which is asymptotically flat to a geometry of the type $adS_k \xx E^l \xx S^m$. The implications of ou

M. Hassaïne, P. A. Horváthy, J. -C. Yera

The non-relativistic Maxwell-Chern-Simons model recently introduced by Manton is shown to admit self-dual vortex solutions with non-zero electric field. The interrelated ``geometric&#39;&#39; and ``hidden&#39;&#39; symmetries are explained. The theory is also extended to (non-relativistic) spinors. A relativistic, self-dual model, whose non-relativistic limi

A. Pajitnov

Let f be a Morse map from a closed manifold to a circle. S.P.Novikov constructed an analog of the Morse complex for f. The Novikov complex is a chain complex defined over the ring of Laurent power series with integral coefficients and finite negative part. This complex depends on the choice of a gradient-like vector field. The homotopy type of the Novikov co

Ken-ji Hamada

We show that the supersymmetric Wilson loops in IIB matrix model give a transition operator from reduced supersymmetric Yang-Mills theory to supersymmetric space-time theory. In comparison with Green-Schwarz superstring we identify the supersymmetric Wilson loops with the asymptotic states of IIB superstring. It is pointed out that the supersymmetry transfor

Rafal Moderski, Marek Sikora, Jean-Pierre Lasota

Most quasars are known to be radio quiet and according to the ``spin paradigm&#39;&#39;, which connects their radio-loudness with the value of the black hole spin, they must harbor very slowly rotating black holes. On the other hand, quasars are powered by accretion which tends to increase the spin of the black hole. We show that the Blandford-Znajek mechani

Feng Pan, J. P. Draayer

An infinite dimensional algebra, which is useful for deriving exact solutions of the generalized pairing problem, is introduced. A formalism for diagonalizing the corresponding Hamiltonian is also proposed. The theory is illustrated with some numerical examples.

Chanju Kim

We calculate the second virial coefficient of anyons whose wave function does not vanish at coincidence points. This kind of anyons appear naturally when one generalizes the hard-core boundary condition according to self-adjoint extension method in quantum mechanics, and also when anyons are treated field theoretically by applying renormalization procedure t

Sajeev John, Valery I. Rupasov

The many-particle spectrum of an isotropic frequency gap medium doped with impurity resonance atoms is studied using the Bethe ansatz technique. The spectrum is shown to contain pairs of quantum correlated ``gap excitations&#39;&#39; and their heavy bound complexes (``gap solitons&#39;&#39;), enabling the propagation of quantum information within the classic

Ali Mostafazadeh

It is shown that the eigenvalue problem for the Hamiltonians of the standard form, $H=p^2/(2m)+V(x)$, is equivalent to the classical dynamical equation for certain harmonic oscillators with time-dependent frequency. This is another indication of the central role played by time-dependent harmonic oscillators in quantum mechanics. The utility of the known resu

G. Q. Li, G. E. Brown

Single photon spectra in heavy-ion collisions at SPS energies are studied in the relativistic transport model that incorporates self-consistently the change of hadron masses in dense matter. We separate the total photon spectrum into `background&#39; arising from the radiative decays of $π^0$ and $η$ mesons, and the `themal&#39; one from other sources. For t

M. S. Fayache, L. Zamick, Y. Y. Sharon

We allow up to $4 \hbarω$ excitations in $^8Be$ relative to the basic configuration $(0s)^4(0p)^4$ in order to see if there are low-lying intruder states in $^8Be$. We use three interactions $-χQ \cdot Q, -χQ \cdot Q$ + spin-orbit, and a realistic (x,y) interaction, where for $x=1,y=1$ one gets values for the spin-orbit and tensor interactions which correspo

A. Fix, H. Arenhoevel

Incoherent $η$-photoproduction on the deuteron is studied for photon energies from threshold up to 720 MeV. The elementary $γN \to ηN$ amplitude is constructed in the frame of a conventional isobar model. Effects of final state interaction are investigated and their role in the cross section as well as in polarization observables is found to be important. In

B. V. Carlson, T. Frederico, F. B. Guimarães

We use the Gorkov formulation of the Dirac-Hartree-Fock-Bogoliubov approximation to nuclear pairing to study the ^1S_0 nucleon-nucleon correlations in nuclear matter. We find the short-range correlations of the ^1S_0 pairing fields to be almost identical to those of the two-nucleon virtual state. We obtain mutually consistent results for the pairing fields,

Michael Christ, Alexander Kiselev

The absolutely continuous spectrum of one-dimensional Schrödinger operators is proved to be stable under perturbation by potentials satisfying mild decay conditions. In particular, the absolutely continuous spectrum of free and periodic Schrödinger operators is preserved under all perturbations $V(x)$ satisfying $|V(x)|\leq C(1+x)^{-α}$, $α>\frac{1}{2}.$ Thi

Ralf Schindler

Assuming that there is no inner model with a strong cardinal, the following is shown: any subset of ω_1 can be made Δ^1_3 (in the codes) by a reasonable set-forcing; there is a reasonable set-generic extension with a Δ^1_3 well-ordering of its reals; 2-step Σ^1_4 absoluteness fails w.r.t. set-sized reasonable forcings.

John H. Schwarz

BPS saturated p-branes play an important role in recent progress in understanding superstring theory and M theory. One approach to understanding the dynamics of p-branes is to formulate an effective (p+1)-dimensional world-volume theory. The construction of such brane actions involves a number of interesting issues. One such issue is how to formulate the act

Sadhan K. Adhikari, Angsula Ghosh

The importance and usefulness of renormalization are emphasized in nonrelativistic quantum mechanics. The momentum space treatment of both two-body bound state and scattering problems involving some potentials singular at the origin exhibits ultraviolet divergence. The use of renormalization techniques in these problems leads to finite converged results for

V. Moretti

A previously introduced method to renormalize the one-loop stress tensor and the one-loop vacuum fluctuations in a curved background by a direct local $ζ$-function approach is checked in some thermal and nonthermal cases. First the method is checked in the case of a conformally coupled massless field in the static Einstein universe where all hypotheses initi

G. Bimonte, R. Musto, A. Stern, P. Vitale

The usual description of 2+1 dimensional Einstein gravity as a Chern-Simons (CS) theory is extended to a one parameter family of descriptions of 2+1 Einstein gravity. This is done by replacing the Poincare&#39; gauge group symmetry by a q-deformed Poincare&#39; gauge group symmetry, with the former recovered when q-> 1. As a result, we obtain a one parameter