March 1997 arXiv papers — page 11

A. Pasquinucci

I discuss the scattering of a graviton (or a dilaton, or an anti-symmetric tensor) on two parallel static Dp-branes. The graviton belongs to a type II string in 10D.

K. G. Chetyrkin

We present the results of analytic calculation of the quark mass anomalous dimension to alpha_s**4.

Stuart Kauffman, Lee Smolin

We argue that in classical and quantum theories of gravity the configuration space and Hilbert space may not be constructible through any finite procedure. If this is the case then the "problem of time" in quantum cosmology may be a pseudo-problem, because the argument that time disappears from the theory depends on constructions that cannot be reali

Franco Nori

Recent experiments and realistic flux-gradient-driven computer simulations provide evidence of plastic flow of flux lines in a superconductor. The striking videos of the onset of vortex motion vividly illustrate the existence of flowing "rivers" of quantized magnetic flux that intermittently form, freeze, and reappear at different locations in the sa

Hisao Hayakawa, Daniel C. Hong

We present two continuum models A and B to study the convective instability of granular materials subjected to vibrations. We carry out the linear stability analysis for model A and uncover the instability mechanism as a supercritical bifurcation of a bouncing solution. We also explicitly determine the onset of convection as a function of control parameters.

V. V. Ponomarenko

As voltage decreases d.c. condctivity of a Tomonaga-Luttinger liquid wire collapses to a small value determined by the length of the wire and its contacts with the leads. In condition that voltage drop (V) mostly occurs across a tunnel barrier inside the wire the tunneling density of states and, hence, the differential conductivity are shown to exhibit an in

J. L. Lebowitz, A. E. Mazel

We prove that, for low-temperature systems considered in the Pirogov-Sinai theory, uniqueness in the class of translation-periodic Gibbs states implies global uniqueness, i.e. the absence of any non-periodic Gibbs state. The approach to this infinite volume state is exponentially fast.

Sandip K. Chakrabarti

We review models which include advective accretion disks onto compact objects and discuss the influence of the centrifugal pressure supported high density region close to the compact objects on the emitted spectra. We show that the stationary and non-stationary spectral properties (such as low and high states, quasi-periodic oscillations, quiescent and risin

Sandip K. Chakrabarti

Accretion disk models have evolved from Bondi flows in the 1950s to Keplerian disks in the 1970s and finally to advective transonic flows in the 1990s. We discuss recent progresses in this subject and show that sub-Keplerian flows play a major role in determining the spectral properties of black holes. Centrifugal pressure supported enhanced density region o

Andrew Gould

The initial results of microlensing surveys toward the Galactic bulge and the LMC are puzzling. Toward the LMC, the total mass in MACHOs is of order half that required to explain the dark matter, but the estimated MACHO mass (~0.4 Msun) is most consistent with stars that should have been seen. Toward the bulge, the total mass is consistent with that given by

Nitin Nitsure

This paper solves the global moduli problem for regular holonomic D-modules with normal crossing singularities on a nonsingular complex projective variety. This is done by introducing a level structure (which gives rise to ``pre-D-modules''), and then introducing a notion of (semi-)stability and applying Geometric Invariant Theory to construct a coar

Ivan Mirković, Kari Vilonen

We outline a proof of a geometric version of the Satake isomorphism. Given a connected, complex algebraic reductive group G we show that the tensor category of representations of the dual group $\check G$ is naturally equivalent to a certain category of perverse sheaves on the loop Grassmannian of G. The above result has been announced by Ginsburg in \cite{G

Detlef Lehmann

The nonrelativistic many-electron system in the forward, exchange and BCS approximation is considered. In this approximation, which is still quartic in the annihilation and creation operators, the model is explicitly solvable for arbitrary space dimension d. The partition function and the correlation functions are given by finite-dimensional integral represe

M. V. Burnashev, A. S. Holevo

The reliability function gives the rate of exponential convergence to zero of the error probability in a communication channel. In this paper bounds for the reliability function of a quantum pure state channel are given, reminiscent of the corresponding classical bounds. This in particular suggests an alternative proof of the coding theorem for quantum noise

Jiang Yi, Han Liang, Ma Wen-Gan, Yu Zeng-Hui

We studied the pair production rate of charged Higgs bosons via gluon-gluon collisions in the general two-Higgs-doublet model. The analysis of its production are made with possible parameter values of Higgs sectors in this model. We find that the production cross sections may be 4 to 41 fermi-bar in the future LHC pp collider with these parameters. The calcu

Kenji Hotta, Keiji Kikkawa, Michihiko Sakamoto

The time development of a model of (2+1)-dimensional torus universe is studied based on background field equations which follow from a string theory. The metrics in various cases are characterized by a real parameter which specifies a ratio of the lengths of two independent cycles. When the parameter is a rational number, the space is asymptotically stretche

L. Burakovsky, T. Goldman

The mass spectrum of P-wave mesons is considered in a nonrelativistic constituent quark model. The results show the common mass degeneracy of the isovector and isodoublet states of the scalar and tensor meson nonets, and do not exclude the possibility of a similar degeneracy of the same states of the axial-vector and pseudovector nonets. Current experimental

Tri Sulistiono

Problems concerning with application of quantum rules on classical phenomena have been widely studied, for which lifted up the idea about quantization and uncertainty principle. Energy quantization on classical example of simple harmonic oscillator has been reviewed in this paper.

N. Khviengia, Z. Khviengia

We construct the N=2, D=9 supergravity theory up to the quartic fermionic terms and derive the supersymmetry transformation rules for the fields modulo cubic fermions. We consider a class of p-brane solutions of this theory, the stainless p-branes, which cannot be isotropically oxidized into higher dimensions. The new stainless elementary membrane and elemen

Olivier de Mirleau

The Frobenius-Schwinger-Dyson equations are a rather high-brow abstract nonsense type of equations describing n-point functions of arbitrarily high composite insertions. It is not clear how to solve or even find approximate solutions of these equations in general, but they are worth investigating because (a certain preferred type of) renormalization of compo

L. Burakovsky, T. Goldman

In a nonrelativistic constituent quark model we find a constraint on the mixing angle of the strange axial-vector mesons, $35^o\stackrel{<}{\sim } θ_K\stackrel{<}{\sim }55^o,$ determined solely by two parameters: the mass difference of the $a_1$ and $b_1$ mesons and the ratio of the constituent quark masses.

L. Burakovsky

By the application of a linear mass spectrum to a composite system of both the pseudoscalar and scalar meson nonets, we find three mass relations for the masses of the scalar states which suggest the $q\bar{q}$ assignment for the scalar meson nonet: $a_0(1320),$ $K_0^\ast (1430),$ $f_0(1500),$ $f_0&#39;(980).$

P. Sawicki

We study the basic features of the two-dimensional quantum Hubbard Model at half-filling by means of the Lüscher algorithm and the algorithm based on direct update of the determinant of the fermionic matrix. We implement the Lüscher idea employing the transfer matrix formalism which allows to formulate the problem on the lattice in $(2+1)$ dimensions. We dis

Ya-Wei Hsueh, B. W. Statt, M. Reedyk, J. S. Xue

We report on NMR measurements in underdoped Pb2Sr2(Y,Ca)Cu3O8+d crystals. A pseudogap is observed in the Knight shift and spin-lattice relaxation rate. In contrast to other underdoped compounds, the pseudogap observed in the Knight shift is weak and occurs at a significantly lower temperature. On the other hand, the effect the pseudogap has on spin-lattice r

Stephan Haas, A. V. Balatsky, Manfred Sigrist, T. M. Rice

A generalization of the Abrikosov-Gorkov equations for non-magnetic impurities in unconventional superconductors is proposed, including higher harmonics in the expansion of the momentum dependent gap function and a momentum dependent impurity scattering potential. This model is treated within a self-consistent calculation to obtain the electronic density of

Nicola Marzari, David Vanderbilt, M. C. Payne

A new method is presented for performing first-principles molecular-dynamics simulations of systems with variable occupancies. We adopt a matrix representation for the one-particle statistical operator Gamma, to introduce a ``projected&#39;&#39; free energy functional G that depends on the Kohn-Sham orbitals only and that is invariant under their unitary tra

S. Kubis, M. Kutschera

Relativistic mean field (RMF) theory of nuclear matter with the isovector scalar mean field corresponding to the delta-meson [a_0(980)] is studied. While the delta-meson mean field vanishes in symmetric nuclear matter, it can influence properties of asymmetric nuclear matter in neutron stars. The RMF contribution due to delta-field to the nuclear symmetry en

J. E. Hesser, P. B. Stetson, W. E. Harris, M. Bolte

We review observational evidence bearing on the formation of a prototypical large spiral galaxy, the Milky Way. New ground- and space-based studies of globular star clusters and dwarf spheroidal galaxies provide a wealth of information to constrain theories of galaxy formation. It appears likely that the Milky Way formed by a combination of rapid, dissipativ

Sergey Cherkis, John H. Schwarz

Using a recently constructed M5-brane world-volume action, we demonstrate that wrapping the M5-brane on K3 gives the heterotic string in seven dimensions. To facilitate the comparison, a new version of the world-sheet action for the Narain-compactified heterotic string, with manifest T duality invariance, is formulated.

Paul B. Slater

We consider a family of prior probability distributions of particular interest, all being defined on the three-dimensional convex set of two-level quantum systems. Each distribution is, following recent work of Petz and Sudar, taken to be proportional to the volume element of a monotone metric on that Riemannian manifold. We apply an entropy-based test (a va

M. R. Frank, T. Meissner

The combined absence of physical realizations of the UA(1) symmetry possessed by the classical QCD action in the chiral limit, and of an isoscalar Goldstone boson associated with its spontaneous breakdown, has been dubbed the UA(1) problem. A formal resolution of this problem proposed by &#39;t Hooft relies on instantons to provide a mass to the would-be Gol

S. Groote, J. G. Körner, A. A. Pivovarov

We extract the strong coupling constant $α_s(m_τ^2)$ from the semileptonic $τ$ decay width taking into account resummation effects from the running of the strong coupling constant. In the $\overline{\rm MS}$ scheme the result reads $α_s=0.375\pm 0.007$ to third order and $α_s=0.378\pm 0.007$ to fourth order in the $β$-function, respectively, where we use the

V. M. Loktev, S. G. Sharapov, V. M. Turkowski

It is shown that in 2D system of the fermions with simplest indirect boson-induced attraction (through the Einstein phonon exchange as an example) along with the normal and superconducting phases there arises a new (called &#34;abnormal normal&#34; or pseudogap) one where the absolute value of the order parameter is finite but its phase is a random quantity.

Muriel Ney-Nifle, A. Peter Young

We study chaos in a two dimensional Ising spin glass by finite temperature Monte Carlo simulations. We are able to detect chaos with respect to temperature changes as well as chaos with respect to changing the bonds, and find that the chaos exponents for these two cases are equal. Our value for the exponent appears to be consistent with that obtained in stud

F. Ghaboussi

We discuss a model where the relation between Hall potential $A_H$ = and gate potential $A_G$, which is manifested by the stepped QHE = curve, is described by an uncertainty relation $ΔA_H . = ΔA_G =3D B(\hbar/e)$.

Guy D. Moore, Neil G. Turok

We develop a topological method of measuring Chern-Simons number change in the real time evolution of classical lattice SU(2) and SU(2) Higgs theory. We find that the Chern-Simons number diffusion rate per physical 4-volume is very heavily suppressed in the broken phase, and that it decreases with lattice spacing in pure Yang-Mills theory, although not as qu

G. Domokos, S. Kovesi-Domokos

If massive neutrinos possess magnetic moments, a magnetic field can cause a spin flip. In the case of Dirac neutrinos the spin flip converts an active neutrino into a sterile one and vice versa. By contrast, if neutrinos are Majorana particles, a spin flip converts them to a neutrino of a different flavor. We examine the behavior of neutrinos in a random mag

P. Dimopoulos, K. Farakos, G. Koutsoumbas

We study the non-compact version of the U(1) gauge-Higgs model in three dimensions for $m_H = 30 GeV.$ We found that, using this formulation, rather modest lattices approach quite well the infinite volume behaviour.The phase transition is first order, as expected for this Higgs mass. The latent heat (in units of $T_{cr}^4$) is compatible with the predictions

E. Kiritsis, C. Kounnas

We show the existence of a supersymmetry breaking mechanism in string theory, where N=4 supersymmetry is broken spontaneously to N=2 and N=1 with moduli dependent gravitino masses. The spectrum of the spontaneously broken theory with lower supersymmetry is in one-to-one correspondence with the spectrum of the heterotic N=4 string. The mass splitting of the N

R. J. Protheroe, W. Bednarek, Q. Luo

We consider the result of acceleration of heavy ions in the slot gap potential of a very young pulsar with a hot polar cap. Photodisintegration of the heavy ions in the radiation field of the polar cap and pulsar surface gives rise to a flux of energetic neutrons. Some fraction of these neutrons interact with target nuclei in the supernova shell to produce n

Mohan Narayan, G. Rajasekaran, Rahul Sinha

It is pointed out that the enhancement of the solar neutrino rate in a real time detector like Super-Kamioka, SNO or Borexino due to neutrino oscillations in the moon during a partial or total solar eclipse may be observable. The enhancement is calculated as a function of the neutrino parameters in the case of three flavor mixing. This enhancement if seen, c

Asta Paloviita, Kalle-Antti Suominen, Stig Stenholm

We consider a laser induced molecular excitation process as a decay of a single energy state into a continuum. The analytic results based on Weisskopf-Wigner approach and perturbation calculations are compared with numerical wave packet results. We find that the decay model describes the excitation process well within the expected parameter region.

Alexander Yu. Vlasov

The using of quantum parallelism is often connected with consideration of quantum system with huge dimension of space of states. The n-qubit register can be described by complex vector with 2^n components (it belongs to n&#39;th tensor power of qubit spaces). For example, for algorithm of factorization of numbers by quantum computer n can be about a few hund

Marian Fecko

A kinematics of the motion of a car is reformulated in terms of the theory of gauge potentials (connection on principal bundle). E(2)-connection originates in the no-slipping contact of the car with a road.

Uldis Berzinsh, Gunnar Haeffler, Dag Hanstorp, Andreas E. Klinkmueller

We report on the first observation of resonance structure in the total cross section for the photodetachment of Li^-. The structure arises from the autodetaching decay of doubly excited ^1P states of Li^- that are bound with respect to the 3p state of the Li atom. Calculations have been performed for both Li^- and H^- to assist in the identification of these

Thomas Mahr, Ingo Rehberg

If a magnetic field normal to the surface of a magnetic fluid is increased beyond a critical value a spontaneous deformation of the surface arises (normal field instability). The instability is subcritical and leads to peaks of a characteristic shape. We investigate the neighborhood of this instability experimentally under the influence of a temporal modulat

P. C. Matthews

In many mathematical models for pattern formation, a regular hexagonal pattern is stable in an infinite region. However, laboratory and numerical experiments are carried out in finite domains, and this imposes certain constraints on the possible patterns. In finite rectangular domains, it is shown that a regular hexagonal pattern cannot occur if the aspect r

Itzhak Bars, Costas Kounnas

General considerations on the unification of A-type and B-type supersymmetries in the context of interacting p-branes strongly suggest that the signature of spacetime includes two timelike dimensions. This leads to the puzzle of how ordinary physics with a single timelike dimension emerges. In this letter we suggest that the two timelike dimensions could be

Jakov Pfaudler

It is pointed out that the strong CP problem may have a natural solution in the context of a recently proposed dualized version of the Standard Model where Higgs fields and generations emerge naturally. Although fermions have finite pole-masses, the fermionic mass matrix itself is factorizable (having only one nonzero eigenvalue) to all orders in perturbatio

C. Saclioglu, S. Nergiz

The twice-dimensionally reduced Seiberg-Witten monopole equations admit solutions depending on two real parameters (b,c) and an arbitrary analytic function f(z) determining a solution of Liouville&#39;s equation. The U(1) and manifold curvature 2-forms F and R^1_2 are invariant under fractional SL(2,R) transformations of f(z). When b=1/2 and c=0 and f(z) is

L. Burakovsky, T. Goldman

The mass spectrum of D-wave mesons is considered in a nonrelativistic constituent quark model. The results show a common mass degeneracy of the isovector and isodoublet states of the 1 $^3D_1$ and 1 $^3D_3$ nonets, and suggest therefore that the $K^\ast (1680)$ cannot be the I=1/2 member of the 1 $^3D_1$ nonet. They also suggest that the $η_2(1870),$ present

Mark B. Wise

B decay sum rules relate exclusive B semileptonic decay matrix elements to forward B-meson matrix elements of operators in HQET. At leading order the operators that occur are the b-quark kinetic energy $λ_1$ and chromomagnetic energy $λ_2$. The latter is determined by the measured $B^*-B$ mass splitting. The derivation of these sum rules is reviewed and pert

P. I. Krastev, J. N. Bahcall

We present the status of FCNC solutions to the solar neutrino problem. Our analysis shows that the FCNC solutions with massless neutrinos provide a good fit to the latest solar neutrino data. Predictions for future experiments are formulated which will permit further tests of these solutions.

Paolo Gambino

The electroweak corrections induced by a heavy top on the main precision observables are now available up to O(g^4 mt^2/mw^2). The new results significantly reduce the theoretical uncertainty and have a sizable impact on the determination of sin^2theta_eff. We give precise predictions for mw and the effective sine in different renormalization schemes, estima

A. Leike

Simple estimates for Z&#39; exclusion limits and Z&#39; model measurements in pp (p bar p) collisions are derived. Due to properties of the structure functions, the Z&#39; exclusion limits depend only logarithmically on the Z&#39; couplings to fermions and on the integrated luminosity. The predicted scaling of Z&#39; exclusion limits and errors of Z&#39; mea

Nils A. Tornqvist

The mechanism where flavor symmetry is broken spontaneously is discussed within a scalar QCD model with effective three-meson couplings. For sufficiently large coupling the model is unstable with respect to quantum loops from mesonic vacuum polarization. It is argued that color and gluons naturally can account for the Goldstone degrees of freedom expected wh

M. Kawasaki, T. Yanagida

Banks and Dine have recently shown that the M theory naturally accommodates the Peccei-Quinn axion. Since the decay constant $F_a$ of the axion is large as $F_a \simeq 10^{15}-10^{16}$GeV, the halo axion is hardly detected in coming axion-search experiments. However, we show that isocurvature fluctuations of the M-theory axion produced at the inflationary ep

Manuel Drees

After a short review of the arguments for the existence of Particle Dark Matter in the Universe, I list the most plausible candidates provided by particle physics, i.e. neutrinos, axions, and WIMPs. In each case I briefly describe how to estimate the relic density, and discuss attempts at detecting these particles. At the end I discuss my personal favorite,

Nima Arkani-Hamed, Hitoshi Murayama

It has been argued that the squarks and sleptons of the first and second generations can be relatively heavy without destabilizing the weak scale, thereby improving the situation with too-large flavor-changing neutral current (FCNC) and CP violating processes. In theories where the soft supersymmetry breaking parameters are generated at a high scale (such as

Reza Tavakol, Roustam Zalaletdinov

We consider the domain of applicability of general relativity (GR), as a classical theory of gravity, by considering its applications to a variety of settings of physical interest as well as its relationship with real observations. We argue that, as it stands, GR is deficient whether it is treated as a microscopic or a macroscopic theory of gravity. We brief

Li-Xin Li

In the appearance of absorption material, the quantum vacuum fluctuations of all kinds of fields may be smoothed out and the spacetime with time machine may be stable against vacuum fluctuations. The chronology protection conjecture might break down, and the anti-chronology protection conjecture might hold: There is no law of physics preventing the appearanc

Li-Xin Li

It is shown that the temperature may be quantized in some spacetime due to the periodically topological structure of the Euclidean section. The quanta of the temperature is the Hawking-Unruh temperature.

Kirill A. Bronnikov, Julio Cesar Fabris

We obtain and study static, spherically symmetric solutions for the Einstein - generalized Maxwell field system in 2n dimensions, with possible inclusion of a massless scalar field. The generalization preserves the conformal invariance of the Maxwell field in higher dimensions. Almost all solutions exhibit naked singularities, but there are some classes of b

James B. Hartle, Donald Marolf

A class of decoherence schemes is described for implementing the principles of generalized quantum theory in reparametrization-invariant `hyperbolic&#39; models such as minisuperspace quantum cosmology. The connection with sum-over-histories constructions is exhibited and the physical equivalence or inequivalence of different such schemes is analyzed. The di

Kirill A. Bronnikov

Static, spherically symmetric configurations of gravity with nonminimally coupled scalar fields are considered in D-dimensional space-times in the framework of generalized scalar-tensor theories. We seek special cases when the system has no naked singularity but instead forms either a black hole, or a wormhole. General conditions when this is possible are fo

Robert Geroch

This is a latex&#39;d version of Robert Geroch&#39;s 1973 notes entitled &#39;Suggestions For Giving Talks&#39;.

Oliver Guenther, Tad Hogg, Bernardo A. Huberman

Embedding microscopic sensors, computers and actuators into materials allows physical systems to actively monitor and respond to their environments. This leads to the possibility of creating smart matter, i.e., materials whose properties can be changed under program control to suit varying constraints. A key difficulty in realizing the potential of smart mat

Michel van Veenendaal, Robert Benoist

This paper makes a comparison between x-ray absorption (XAS) and resonant inelastic x-ray scattering (RIXS) in the rare earths. Atomic calculations are given for 2p -> 4f and 2p -> 5d XAS. The latter calculation includes the contraction and expansion of the 5d orbitals resulting from the complete exchange interaction with the 4f electrons. The radiative deca

Hisao Hayakawa, Daniel C. Hong

We present a thermodynamic theory of weakly excited two-dimensional granular systems from the view point of elementary excitations of spinless Fermion systems. We introduce a global temperature T that is associated with the acceleration amplitude Γin a vibrating bed. We show that the configurational statistics of weakly excited granular materials in a vibrat

Jorge Kohanoff, Sandro Scandolo, Guido L. Chiarotti, Erio Tosatti

By performing constant-pressure variable-cell ab initio molecular dynamics simulations we find a quadrupolar orthorhombic structure, of $Pca2_1$ symmetry, for the broken symmetry phase (phase II) of solid H2 at T=0 and P =110 - 150 GPa. We present results for the equation of state, lattice parameters and vibronic frequencies, in very good agreement with expe

Yusuke Kato, Takashi Yamamoto, Mitsuhiro Arikawa

We consider the physical properties of elementary excitations of the Calogero-Sutherland (CS) model with SU(K) internal symmetry. From the results on the thermodynamics of this model, we obtain the charge, spin, and statistics of elementary excitations. Combining this knowledge and the known results on the dynamics in the spinless CS model, we propose the ex

X. -M. Zhu, B. Sundqvist

The vortex motion in a superfluid or a type II superconductor is similar to the electron motion in a magnetic field, because they both feel a transverse force. The vortex dynamics in a superconductor is a basic property of the superconductivity which remains controversial. It is also responsible for a large class of observed physical phenomena. We will exami

V. Prigodin, B. L. Altshuler

This paper is devoted to the statistics of the quantum eigenfunctions in an ensemble of finite disordered systems (metallic grains). We focus on moments of inverse participation ratio. In the universal random matrix limit that corresponds to the infinite conductance of the grains, these moments are self-averaging quantities. At large but finite conductance t

Gwang-Hee Kim

We study the quantum nucleation in a thin ferromagnetic film placed in a magnetic field at an arbitrary angle. The dependence of the quantum nucleation and the temperature of the crossover from thermal to quantum regime on the direction and the strength of the applied field are presented. It is found that the maximal value of the rate and that of the crossov

A. Z. Menshikov, S. G. Bogdanov, Y. N. Skryabin

The conclusions arising from the multiple small angle neutron scattering theory, developed recently by S.V. Maleyev, R.V. Pomortsev and Y.N. Skryabin [Phys. Rev. B 50 7133 (1994)] for the value of Born parameter more than 1, are experimentally confirmed by magnetic scattering from domain structure of pure Fe and Ni, as well as Fe_{65}Ni_{35} alloy. The cross

M. Krech

The short-time evolution of a growing interface is studied analytically and numerically for the Kadar-Parisi-Zhang (KPZ) universality class. The scaling behavior of response and correlation functions is reminiscent of the ``initial slip&#39;&#39; behavior found in purely dissipative critical relaxation (model A). Unlike model A the initial slip exponent for

Henryk Fuks

Recently, Land and Belew [Phys. Rev. Lett. 74, 5148 (1995)] have shown that no one-dimensional two-state cellular automaton which classifies binary strings according to their densities of 1&#39;s and 0&#39;s can be constructed. We show that a pair of elementary rules, namely the ``traffic rule&#39;&#39; 184 and the ``majority rule&#39;&#39; 232, performs the

Deepto Chakrabarty, Lars Bildsten, Mark H. Finger, John M. Grunsfeld

Over five years of daily hard X-ray (>20 keV) monitoring of the 2-min accretion-powered pulsar GX 1+4 with the Compton Gamma Ray Observatory/BATSE large-area detectors has found nearly continuous rapid spin-down, interrupted by a bright 200-d spin-up episode. During spin-down, the torque becomes more negative as the luminosity increases (assuming that the 20

J. L. McCauley

Unless there is evidence for fractal scaling with a single exponent over distances .1 <= r <= 100 h^-1 Mpc then the widely accepted notion of scale invariance of the correlation integral for .1 <= r <= 10 h^-1 Mpc must be questioned. The attempt to extract a scaling exponent νfrom the correlation integral n(r) by plotting log(n(r)) vs. log(r) is unreliable u

S. Hancock, C. M. Gutierrez, R. D. Davies, A. N. Lasenby

We present a detailed analysis of the cosmic microwave background structure in the Tenerife Dec=+40 degrees data. The effect of local atmospheric contributions on the derived fluctuation amplitude is considered, resulting in an improved separation of the intrinsic CMB signal from noise. Our analysis demonstrates the existence of common structure in independe

D. D. Dixon, T. O. Tumer, A. D. Zych, L. X. Cheng

We present progress toward using scanned OSSE observations for mapping and sky survey work. To this end, we have developed a technique for detecting pointlike sources of unknown number and location, given that they appear in a background which is relatively featureless or which can be modeled. The technique, based on the newly developed concept and mean fiel

C. Ciliberto, K. Hulek

The union of two quintic elliptic scrolls in P^4 intersecting transversally along an elliptic normal quintic curve is a singular surface Z which behaves numerically like a bielliptic surface. In the appendix to the paper [W. Decker et al.: Syzygies of abelian and bielliptic surfaces in P^4, alg-geom/9606013] where the equations of this singular surface were

Michael R. Douglas

We obtain actions for N D-branes occupying points in a manifold with arbitrary Kahler metric. In one complex dimension, the action is uniquely determined (up to second order in commutators) by the requirement that it reproduce the masses of stretched strings and by imposing supersymmetry. These conditions are very restrictive in higher dimensions as well. Th

Jorge Alfaro

These lectures on the Batalin-Vilkovisky method of quantization were delivered at &#34;VII Mexican School of Particles and Fields&#34;, Mérida, México, October 30-November 6, 1996. In section II, we study the derivation of BV from Schwinger-Dyson-BRST symmetry; in section III, we consider some generalizations of the BV structure suggested by our approach. In

Tom Banks, Nathan Seiberg, Eva Silverstein

We study the symmetry structure of N=8 quantum mechanics, and apply it to the physics of D0-brane probes in type I&#39; string theory. We focus on the theory with a global $Spin(8)$ R symmetry which arises upon dimensional reduction from $2d$ field theory with $(0,8)$ supersymmetry. There are several puzzles involving supersymmetry which we resolve. In parti

Stephen L. Adler

We show that the recently proposed matrix model for M theory obeys the cyclic trace assumptions underlying generalized quantum or trace dynamics. This permits a verification of supersymmetry as an operator calculation, and a calculation of the supercharge density algebra by using the generalized Poisson bracket, in a basis-independent manner that makes no re

I. I. Mazin, David Singh

We propose a quantitative model for triplet superconductivity in Sr_2RuO_4 based on first principles calculations for the electronic structure and magnetic susceptibility. The superconductivity is due to ferromagnetic spin fluctuations, that are strong at small wave vectors. The calculated effective mass renormalization, renormalized susceptibility, and supe

M. R. Brown

The composition of the quantum potential and its role in the breakdown of classical symplectic symmetry in quantum mechanics is investigated. General expressions are derived for the quantum potential in both configuration space and momentum space representations. By comparing the configuration space and momentum space representations of the causal interpreta

Jose-Luis Rosales

We speculate about the spacetime description due to the presence of Lorentzian wormholes (handles in spacetime joining two distant regions or other universes) in quantum gravity. The semiclassical rate of production of these Lorentzian wormholes in Reissner-Nordström spacetimes is calculated as a result of the spontaneous decay of vacuum due to a real tunnel

J. L. F. Barbon

We consider configurations of rotated NS-branes leading to a family of four-dimensional N=1 super-QCD theories, interpolating between four-dimensional analogues of the Hanany-Witten vacua, and the Elitzur-Giveon-Kutasov configuration for N=1 duality. The rotation angle is the N=2 breaking parameter, the mass of the adjoint scalar in the N=2 vector multiplet.

Yuri B. Suris

A fairly complete list of Toda-like integrable lattice systems, both in the continuous and discrete time, is given. For each system the Newtonian, Lagrangian and Hamiltonian formulations are presented, as well as the 2x2 Lax representation and r-matrix structure. The material is given in the &#34;no comment&#34; style, in particular, all proofs are omitted.

Ming Li, John Tromp, Paul Vitanyi

Reversible simulation of irreversible algorithms is analyzed in the stylized form of a `reversible&#39; pebble game. While such simulations incur little overhead in additional computation time, they use a large amount of additional memory space during the computation. The reacheable reversible simulation instantaneous descriptions (pebble configurations) are

D. V. Antonov

Starting with the representation of the Wilson average in the Euclidean 4D compact QED as a partition function of the Universal Confining String Theory, we derive for it the corresponding loop equation, alternative to the familiar one. In the functional momentum representation the obtained equation decouples into two independent ones, which describe the dyna

Jose F. Morales, Marco Serone

We study the moduli dependence of a class of couplings in $K3\times T^2$ compactifications of type I string theory, for which one-loop amplitudes can be written in terms of an N=2 supersymmetric index. This index is determined for generic models as a function of the BPS spectrum. As an application we compute the one-loop moduli dependence of the $F_g W^{2g}$

Angelo Vistoli

This is an expository paper on the subject of the title. It assumes basic scheme theory, commutative and homological algebra.

F. Delduc, E. Ivanov, E. Sokatchev

We propose a formulation of the massive spinning particle in terms of physical bosonic and fermionic fields only. We make use neither of auxiliary objects of the type of $γ_5$ nor of gauge fields. The model is to be used as a suitable starting point for a forthcoming study of the rigid superparticle.

R. F. Mushotzky, C. A. Scharf

We have obtained the first large sample of accurate temperatures for clusters at z>0.14 from ASCA. We compare the luminosity temperature (L-T) distribution for these clusters with the low redshift sample of David et al (1993) and find that there is no evidence for evolution. We also find that the intrinsic variance in this relation is roughly constant with r

Andreas E. Klinkmueller, Gunnar Haeffler, Dag Hanstorp, Igor Yu. Kiyan

A Feshbach resonance associated with the 1s3s4s ^{4}S state of He^{-} has been observed in the He(1s2s ^{3}S) + e^- (εs) partial photodetachment cross section. The residual He(1s2s ^{3}S) atoms were resonantly ionized and the resulting He^+ ions were detected in the presence of a small background. A collinear laser-ion beam apparatus was used to attain both

S. D. Bass

Photoproduction spin sum-rules offer a new window on the spin structure of the nucleon that complements the information we can learn from polarised deep inelastic scattering experiments. We review the theory and present status of the Drell-Hearn-Gerasimov sum-rule in QCD, emphasising the possible relation between the present ``discrepancy&#39;&#39; in this s

Youngjai Kiem, Chang-Yeong Lee, Dahl Park

We find exactly solvable dilaton gravity theories containing a U(1) gauge field in two dimensional space-time. The classical general solutions for the gravity sector (the metric plus the dilaton field) of the theories coupled to a massless complex scalar field are obtained in terms of the stress-energy tensor and the U(1) current of the scalar field. We disc