November 1999 arXiv papers — page 9

Hitoshi Seo

The charge ordering phenomena in quasi two-dimensional 1/4-filled organic compounds (ET)_2X (ET=BEDT-TTF) are investigated theoretically for the $θ$ and $α$-type structures, based on the Hartree approximation for the extended Hubbard models with both on-site and intersite Coulomb interactions. It is found that charge ordered states of stripe-type are stabili

K. Sugiyama

The probabilistic prediction of quantum theory is mystery. I solved the mystery by a geometrical interpretation of a wave function. This suggests the unification between quantum theory and the theory of relativity. This suggests Many-Worlds Interpretation is true, too.

Gilad Gour, L. Sriramkumar

The Brownian motion of small particles interacting with a field at a finite temperature is a well-known and well-understood phenomenon. At zero temperature, even though the thermal fluctuations are absent, quantum fields still possess vacuum fluctuations. It is then interesting to ask whether a small particle that is interacting with a quantum field will exh

Ana Proykova, Dessislava Nikolova, R. Stephen Berry

The dynamic orientational order-disorder transition of clusters consisting of octahedral molecules is formulated in terms of symmetry-adapted rotator functions. The transition from a higher-temperature body-centered-cubic, orientationally disordered phase to a lower-temperature, monoclinic, orientationally-ordered phase is a two-step process. The higher-temp

Yuqing Wang, David T. W. Chik, Z. D. Wang

The coherence resonance (CR) of globally coupled Hodgkin-Huxley neurons is studied. When the neurons are set in the subthreshold regime near the firing threshold, the additive noise induces limit cycles. The coherence of the system is optimized by the noise. A bell-shaped curve is found for the peak height of power spectra of the spike train, being significa

Colin Rourke, Brian Sanderson

A homology stratification is a filtered space with local homology groups constant on strata. Despite being used by Goresky and MacPherson [Intersection homology theory: II, Inventiones Mathematicae, 71 (1983) 77-129] in their proof of topological invariance of intersection homology, homology stratifications do not appear to have been studied in any detail an

Shigeyuki Morita

In this paper, we survey recent works on the structure of the mapping class groups of surfaces mainly from the point of view of topology. We then discuss several possible directions for future research. These include the relation between the structure of the mapping class group and invariants of 3-manifolds, the unstable cohomology of the moduli space of cur

Mark L. Agranovsky, Eric Todd Quinto

We consider the Cauchy problem for the wave equation in the whole space, R^n, with initial data which are distributions supported on finite sets. The main result is a precise description of the geometry of the sets of stationary points of the solutions to the wave equation.

Moira Chas, Dennis Sullivan

Consider two families of closed oriented curves in a d-manifold. At each point of intersecction of a curve of one family with a curve of the other family, form a new closed curve by going around the first curve and then going around the second. Typically, an i-dimensional family and a j-dimensional family will produce an (i+j-d+2)-dimensional family. Our pur

Laura Anderson, James F. Davis

Matroid bundles, introduced by MacPherson, are combinatorial analogues of real vector bundles. This paper sets up the foundations of matroid bundles, and defines a natural transformation from isomorphism classes of real vector bundles to isomorphism classes of matroid bundles, as well as a transformation from matroid bundles to spherical quasifibrations. The

Frank Quinn

A group-category is an additively semisimple category with a monoidal product structure in which the simple objects are invertible. For example in the category of representations of a group, 1-dimensional representations are the invertible simple objects. This paper gives a detailed exploration of "topological quantum field theories" for group-catego

Laurence R. Taylor

We say that a topologically embedded 3-sphere in a smoothing of Euclidean 4-space is a barrier provided, roughly, no diffeomorphism of the 4-manifold moves the 3-sphere off itself. In this paper we construct infinitely many one parameter families of distinct smoothings of 4-space with barrier 3-spheres. \par The existence of barriers implies, amongst other t

Lee Rudolph

Let S(D) be the surface produced by applying Seifert's algorithm to the oriented link diagram D. I prove that if D has no negative crossings then S(D) is a quasipositive Seifert surface, that is, S(D) embeds incompressibly on a fiber surface plumbed from positive Hopf annuli. This result, combined with the truth of the `local Thom Conjecture', has va

Kenichiro Aoki, Dimitri Kusnezov

We study the classical non-equilibrium statistical mechanics of scalar field theory on the lattice. Steady states are analyzed near and far from equilibrium. The bulk thermal conductivity is computed, including its temperature dependence. We examine the validity of linear response predictions, as well as properties of the non-equilibrium steady state. We fin

P. Marage

A review is presented of numerous recent results, particularly those submitted to the EPS-HEP99 conference: very high Q^2 ep interactions and direct tests of the Standard Model, new measurements of the structure of the proton (including high x parton distributions and tests of QCD involving the gluon distribution), low x physics (tests of the BFKL evolution)

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

We test the sensitivity of bottom baryon observables with regard to the choice of the interpolating three-quark currents within the relativistic three-quark model. We have found that the semileptonic decay rates are clearly affected by the choice of currents, whereas the asymmetry parameters show only a very weak dependence on the choice of current.

G. Abbiendi, the OPAL collaboration

The inclusive production of D*+- mesons in photon-photon collisions has been measured using the OPAL detector at LEP at e+e- centre-of-mass energies of 183 and 189GeV. The D* mesons are reconstructed in their decay to D0pi+ with the D0 observed in the two decay modes Kpi+ and Kpi+pi-pi+. After background subtraction, 100.4+-12.6(stat) D*+- mesons have been s

G. Abbiendi, the OPAL collaboration

The branching ratio of the tau lepton to a neutral K meson is measured from a sample of approximately 200,000 tau decays recorded by the OPAL detector at centre-of-mass energies near the Z0 resonance. The measurement is based on two samples which identify one-prong tau decays with KL and KS mesons. The combined branching ratios are measured to be B(tau- -->p

Jeffrey L. Billeter, Robert A. Pelcovits

To model a nematic emulsion consisting of a surfactant-coated water droplet dispersed in a nematic host, we performed a molecular dynamics simulation of a droplet immersed in a system of 2048 Gay-Berne ellipsoids in a nematic phase. Strong radial anchoring at the surface of the droplet induced a Saturn ring defect configuration, consistent with theoretical p

Xiaomin Zu, Kwon Park, Jainendra K. Jain

This study provides a theoretical rationalization for the intriguing experimental observation regarding the equality of the normalized masses of composite fermions carrying two and four flux quanta, and also demonstrates that the mass of the latter type of composite fermion has a substantial filling factor dependence in the filling factor range $4/17 > ν> 1/

Catalin Pascu Moca

(1) The temperature dependence of the specific heat for a marginal Fermi liquid has been calculated. (2) We calculated the self-energy at T=0 for a two dimensional fermionic system with hyperbolic dispersion. The existence of the saddle points in the energy gives rise to a marginal behavior. (3) We showed that the two-dimensional fermionic system with the en

Maurice H. P. M. van Putten

Gamma-ray bursts (GRBs) appear as the brightest transient phenomena in the Universe. The nature of the central engine in GRBs is a missing link in the theory of fireballs to their stellar mass progenitors. Here it is shown that rotating black holes produce electron-positron outflow when brought into contact with a strong magnetic field. The outflow is produc

E. Waxman

The recent detection of delayed, low energy emission from Gamma-Ray Burst (GRB) sources confirmed the cosmological origin of the bursts and provided support for models where GRBs are produced by the dissipation of the kinetic energy of relativistic fireballs. In this review, ultra high energy, >10^{19} eV, cosmic-ray and high energy, 100 TeV, neutrino produc

James W. Wadsley, Craig J. Hogan, Scott F. Anderson

A new method to extract Omega_b from high redshift intergalactic absorption is described, based on the distribution of HeII Ly-alpha optical depths in the voids in the ionization zone of quasars. A preliminary estimate from recent HST-STIS spectra of PKS 1935-692 at z=3 gives Omega_b h^2 = 0.013^{+0.002}_{-0.001} (1-sigma statistical errors, for a Lambda-CDM

S. Abbas, A. Abbas, S. Mohanty

Clumped dark matter arises naturally within the framwork of generic cosmological dark matter models. Invoking the existence of dark matter clumps can also solve may unexplained mysteries in astrophysics and geology or geophysics, eg. the galactic gamma-ray halo and the periodic terrestrial flood basalt volcanic episodes. Clumped dark matter is dynamically st

Ken Sasaki, Tsuneo Uematsu

Spin-dependent parton distributions in the polarized virtual photon are investigated in QCD up to the next-to-leading order (NLO). In the case $Λ^2 \ll P^2 \ll Q^2$, where $-Q^2$ ($-P^2$) is the mass squared of the probe (target) photon, parton distributions can be predicted completely up to the NLO, but they are factorization-scheme-dependent. Parton distri

H. Ejiri, J. Engel, R. Hazama, P. Krastev

Spectroscopic studies of two beta-rays from 100Mo are shown to be of potential interest for investigating both the Majorana neutrino mass by neutrinoless double beta-decay and low energy solar neutrino's by inverse beta-decay. With a multi-ton 100Mo detector, coincidence studies of correlated beta-beta from neutrinoless double beta-decay, together with t

Michael Martin Nieto, D. Rodney Truax

We attack the specific time-dependent Hamiltonian problem H=-{1/2} (t_o/t)^a \partial_{xx} + (1/2) ω^2 (t/t_o)^b x^2. This corresponds to a time-dependent mass (TM) Schrödinger equation. We give the specific transformations to a different time-dependent quadratic Schrödinger equations (TQ) and to a different time-dependent oscillator (TO) equation. For each

Michael Martin Nieto, D. Rodney Truax

In this paper, we attack the specific time-dependent Hamiltonian problem H=-{1/2}e^{Υ(t-t_o)}\partial_{xx} +\lfrac{1}{2}ω^2e^{-Υ(t-t_o)}x^2. This corresponds to a time-dependent mass (TM) Schrödinger equation. We give the specific transformations to i) the more general quadratic (TQ) Schrödinger equation and to ii) a different time-dependent oscillator (TO)

D. B. Sanders, D. -C. Kim, J. M. Mazzarella, J. A. Surace

Complete samples of ultraluminous infrared galaxies have been imaged at R-band and K-band from Mauna Kea. Here we present a preliminary analysis of the host galaxy magnitudes and the 1-D radial profiles for a subset of objects in the IRAS 1-Jy sample of ULIGs (z < 0.3), and compare these properties with recently published data for &#34;low-z&#34; QSOs. ULIGs

Ilki Kim, Guenter Mahler

We study a 2-spin quantum Turing architecture, in which discrete local rotations α_m of the Turing head spin alternate with quantum controlled NOT-operations. We show that a single chaotic parameter input α_m leads to a chaotic dynamics in the entire Hilbert space. The instability of periodic orbits on the Turing head and `chaos swapping&#39; onto the Turing

Wen-Fa Lu

Within the framework of thermofield dynamics, we construct a thermalized coherent thermal state, which is a general type of the coherent state with the thermal effects and can be presumably produced experimentally. The wavefunction and the density matrix element in the coordinate repersentation are calculated, and furthermore we give the probability densitie

Dimitri Kusnezov, Aurel Bulgac, Giu Do Dang

Stochastic processes are shown to emerge from the time evolution of complex quantum systems. Using parametric, banded random matrix ensembles to describe a quantum chaotic environment, we show that the dynamical evolution of a particle coupled to such environments displays a variety of stochastic behaviors, ranging from turbulent diffusion to Lévy processes

Takao Matumoto

If the fundamental group of the complement of a smooth embedding f: S^2 \subset R^4 is a cyclic group, the map can be deformed to the standard embedding by a generic one-parameter family with at most cusp singularities. If two smooth embeddings are connected by such a deformation, they will be called cusp equivalent. We will discuss the relation of three equ

W. B. R. Lickorish

Here are versions of the proofs of two classic theorems of combinatorial topology. The first is the result that piecewise linearly homeomorphic simplicial complexes are related by stellar moves. This is used in the proof, modelled on that of Pachner, of the second theorem. This states that moves from only a finite collection are needed to relate two triangul

D. Kotschick

We show that a compact complex surface which fibers smoothly over a curve of genus >1 with fibers of genus >1 fibers holomorphically. We deduce an improvement of a result in [D Kotschick, Math. Research Letters, 5 (1998) 227-234], and a characterisation of fibered surfaces with zero signature.

Tsuyoshi Kobayashi

In this paper, we show that any unknotting tunnel for a two bridge knot is isotopic to either one of known ones. This together with Morimoto-Sakuma&#39;s result gives the complete classification of unknotting tunnels for two bridge knots up to isotopies and homeomorphisms.

M. Farber

In this paper we construct a Universal chain complex, counting zeros of closed 1-forms on a manifold. The Universal complex is a refinement of the well known Novikov complex; it relates the homotopy type of the manifold, after a suitable noncommutative localization, with the numbers of zeros of different indices which may have closed 1-forms within a given c

S. J. Dilworth, Maria Girardi, W. B. Johnson

A separable Banach space X contains $\ell_1$ isomorphically if and only if X has a bounded wc_0^*-stable biorthogonal system. The dual of a separable Banach space X fails the Schur property if and only if X has a bounded wc_0^*-biorthogonal system.

E. Andruchow, G. Corach, D. Stojanoff

Let X be a right Hilbert C*-module over A. We study the geometry and the topology of the projective space P(X) of X, consisting of the orthocomplemented submodules of X which are generated by a single element. We also study the geometry of the p-sphere S_p(X) and the natural fibration S_p(X) \to P(X), where S_p(X)={x\in X: <x,x>=p}, for p in A a projection.

A. Iliev, D. Markushevich

A generic quartic 3-fold X admits a 7-dimensional family of representations as the Pfaffian of an 8 by 8 skew-symmetric matrix of linear forms. This provides a 7-dimensional moduli space M of rank 2 vector bundles on X. A precise geometric description of a 14-dimensional family of half-canonical curves C of genus 15 in X such that the above vector bundles ar

Xiao-Song Lin, Zhenghan Wang

By calculating the Fermat limit of certain q-Fermat functions, we get explicit surgery formulae for the second and third Ohtsuki invariants for homology 3-spheres. The surgery formula of the second Ohtsuki invariant λ_2, combined with an argument using the general theory of finite type invariants of homology 3-spheres, leads to a congruence relation between

Charles Livingston

The concordance group of algebraically slice knots is the subgroup of the classical knot concordance group formed by algebraically slice knots. Results of Casson and Gordon and of Jiang showed that this group contains in infinitely generated free (abelian) subgroup. Here it is shown that the concordance group of algebraically slice knots also contain element

M. Chaves, H. Morales

Generalized Yang-Mills theories have a covariant derivative that employs both scalar and vector bosons. Here we show how grand unified theories of the electroweak and strong interactions can be constructed with them. In particular the SU(5) GUT can be obtained from SU(6) with SU(5)xU(1) as a maximal subgroup. The choice of maximal subgroup also determines th

Chuan-Tsung Chan, Wei-Shu Hou

We study the mixing angle θ_{Oψ} and mixing amplitude f_{Oψ} of J/psi and vector glueball O, in the framework of potential models of heavy quarks and constituent gluons. While the state vectors of J/psi and O are constructed from the wave functions of few-body Schroedinger equations, the mixing dynamics is governed by perturbative QCD. We obtain a value of t

Thomas Hambye, Ernest Ma, Utpal Sarkar

It is known that realistic neutrino masses for neutrino oscillations may be obtained from R parity nonconserving supersymmetry. It is also known that such interactions would erase any preexisting lepton or baryon asymmetry of the Universe because of the inevitable intervention of the electroweak sphalerons. We now show how a crucial subset of these R parity

M. Bleicher, S. A. Bass, L. V. Bravina, W. Greiner

The Ultra-relativistic Quantum Molecular Dynamics model (UrQMD) is used to study global observables in central reactions of Au+Au at $\sqrt{s}=200$ AGeV (RHIC). Strong stopping governed by massive particle production is predicted if secondary interactions are taken into account. The underlying string dynamics and the early hadronic decoupling implies only sm

Romuald A. Janik, Maciej A. Nowak, Gabor Papp, Ismail Zahed

We model the effects of a large number of zero and near-zero modes in the QCD partition function by using sparse chiral matrix models with an emphasis on the quenched topological susceptibility in the choice of the measure. At finite temperature, the zero modes are not affected by temperature but are allowed to pair into topologically neutral near-zero modes

JLQCD Collaboration, S. Aoki, M. Fukugita, S. Hashimoto

We present a non-perturbative calculation for the pion decay constant with quenched Kogut-Susskind quarks. Numerical simulations are carried out at $β= 6.0$ and 6.2 with various operators extending over all flavors. The renormalization correction is applied for each flavor by computing non-perturbative renormalization constants, and it is compared with a per

Klaus Pretzl

The development of cryogenic calorimeters was originally motivated by the fact that very low energy thresholds and excellent energy resolutions can be achieved by these devices. Cryogenic devices are widely used in double beta decay experiments, in cosmological dark matter searches, in x-ray detection of galactic and extragalactic objects as well as in cosmi

Mourad Daoudi

A review of B B-bar mixing results at the end of July 1999 is presented. Emphasis is put on recent measurements of Delta-Md and Delta-Ms. For Delta-Md, the new world average is Delta-Md = 0.473 +- 0.016 ps-1. For Delta-Ms, the new world average 95% CL limit is 12.4 ps-1, with a sensitivity of 14.2 ps-1. Other related results are covered very briefly.

H. C. Rosu, J. Socorro

The WDW equation of arbitrary Hartle-Hawking factor ordering for several minisuperspace universe models, such as the pure gravity FRW and Taub ones, is mapped onto the dynamics of corresponding classical oscillators. The latter ones are studied by the classical Ermakov invariant method, which is a natural aproach in this context. For the more realistic case

D. V. Dmitriev, V. Ya. Krivnov, A. A. Ovchinnikov

We have found the exact ground state for two electronic models on a linear chain. The first model describes half-filling electron system in the ferromagnet--antiferromagnet transition point. In the singlet ground state the spin correlators show giant spiral magnetic ordering with the period of a spiral equals to the system size. The second electronic model d

Claudia Filippi, C. J. Umrigar

In order to find the equilibrium geometries of molecules and solids and to perform ab initio molecular dynamics, it is necessary to calculate the forces on the nuclei. We present a correlated sampling method to efficiently calculate numerical forces and potential energy surfaces in diffusion Monte Carlo. It employs a novel coordinate transformation, earlier

Wolfgang Häusler

Low energy spectra of isotropic quantum dots are calculated in the regime of low electron densities where Coulomb interaction causes strong correlations. The earlier developed pocket state method is generalized to allow for continuous rotations. Detailed predictions are made for dots of shallow confinements and small particle numbers, including the occurance

N. Rajewsky, T. Sasamoto, E. R. Speer

We study the stationary state of a simple exclusion process on a ring which was recently introduced by Arndt {\it et al} [J. Phys. A {\bf 31} (1998) L45;cond-mat/9809123]. This model exhibits spatial condensation of particles. It has been argued that the model has a phase transition from a ``mixed phase&#39;&#39; to a ``disordered phase&#39;&#39;. However, i

K. -K. Voo, W. C. Wu

We present an interpretation of the recent neutron data on the commensurate and incommensurate spin fluctuations found in YBa_2d$Cu_3O_{6+y} based on a special configuration of the electronic dispersion and intervention from the d_{x^2-y^2}-wave superconducting phase. The observed switch over between the commensurate and incommensurate fluctuation spectra at

A. I. Lichtenstein, M. I. Katsnelson

We present a new approach to investigate the coexistence of antiferromagnetism and d-wave superconductivity in the two dimensional extended Hubbard model within a numerically exact cluster dynamical mean-field approximation. Self-consistent solutions with two non-zero order parameters exists in the wide range of doping level and temperatures. A linearized eq

Jonathan Miller

I suggest that electron localization by random flux and passive transport in quenched velocity fields in two dimensions be studied as perturbations of the simple operator ${\cal K}={\bf A} \cdot \nabla$, with incompressible velocity field/vector potential ${\bf A}=\nabla \times ϕ=(-\partial_y,\partial_x)ϕ$. This operator has an infinitely degenerate subspace

Michael Feast, Patricia Whitelock

A period-metallicity relation for oxygen-rich Miras derived from globular clusters is applied to similar variables in the galactic Bulge. The metallicity distribution in the Bulge thus obtained is in good agreement with that derived from K giants. This suggests that the periods of Miras are useful indicators of metallicity distributions, at least in old syst

Koji Mukai, Alan P. Smale

The Low Mass X-ray Binary (LMXB) X1822-330 in NGC 6652 is one of 12 bright, or transient, X-ray sources to have been discovered in Globular Clusters. We report on a serendipitous ASCA observation of this Globular Cluster LMXB, during which a Type I burst was detected and the persistent, non-burst emission of the source was at its brightest level recorded to

Guo-Hong Wu, Amarjit Soni

We explore charged-Higgs cp-violating effects in a specific type III two-Higgs doublet model which is theoretically attractive as it accommodates the large mass of the top quark in a natural fashion. Two new CP-violating phases arise from the right-handed up quark sector. We consider CP violation in both neutral and charged B decays. Some of the important fi

R. C. Rashkov, K. S. Viswanathan

In the present paper we study SU(N)->S(U(N/2)xU(N/2)) symmetry breaking in N=4 SYM via AdS/CFT correspondence. We consider two stacks of N/2 parallel D3 branes separated by a distance 2\vec d. In this case there is mixing between the different l-wave dilatonic KK modes. We calculate certain the two point correlation functions in the dual gauge theory. Due to

Howard L. Richards, Saul D. Cohen, T. L. Einstein, M. Giesen

Recently it has been recognized that the so-called generalized Wigner distribution may provide at least as good a description of terrace width distributions (TWDs) on vicinal surfaces as the standard Gaussian fit and is particularly applicable for weak repulsions between steps, where the latter fails. Subsequent applications to vicinal copper surfaces at var

S. G. Bompadre, Arthur F. Hebard, Valeri N. Kotov, D. Hall

We investigate the magnetic field dependence of the spin-Peierls transition in NaV$_2$O$_5$ in the field range 16T-30T. The transition temperature exhibits a very weak variation with the field, suggesting a novel mechanism for the formation of the spin-Peierls state. We argue that a charge ordering transition accompanied by singlet formation is consistent wi

S. I. Vainshtein, S. M. Chitre, A. V. Olinto

We propose a mechanism for the fast dissipation of magnetic fields which is effective in a stratified medium where ion motions can be neglected. In such a medium, the field is frozen into the electrons and Hall currents prevail. Although Hall currents conserve magnetic energy, in the presence of density gradients, they are able to create current sheets which

Arun Kumar Pati, Samuel L. Braunstein

A photon in an arbitrary polarization state cannot be cloned perfectly. But suppose that at our disposal we have several copies of an unknown photon. Is it possible to delete the information content of one or more of these photons by a physical process? Specifically, if two photons are in the same initial polarization state is there a mechanism that produces

Martin Rainer

Motivated by the invariance of current representations of quantum gravity under diffeomorphisms much more general than isometries, the Haag-Kastler setting is extended to manifolds without metric background structure. First, the causal structure on a differentiable manifold M of arbitrary dimension (d+1>2) can be defined in purely topological terms, via cone

Yohko Tsuboi, Kensuke Imanishi, Katsuji Koyama, Nicolas Grosso

With ASCA, we have detected three X-ray flares from the Class I protostar YLW15. The flares occurred every ~20 hours and showed an exponential decay with time constant 30-60 ks. The X-ray spectra are explained by a thin thermal plasma emission. The plasma temperature shows a fast-rise and slow-decay for each flare with kT_{peak}~4-6 keV. The emission measure

Geoffrey B. West

Some of the basic concepts regarding asymptotic series are reviewed. A heuristic proof is given that the divergent QCD perturbation series is asymptotic. By treating it as an asymptotic expansion we show that it makes sense to keep only the first few terms. The example of e^+e^- annihilation is considered. It is shown that by keeping only the first few terms

A. A. Coley, R. J. van den Hoogen

We investigate the dynamical properties of a class of spatially homogeneous and isotropic cosmological models containing a barotropic perfect fluid and multiple scalar fields with independent exponential potentials. We show that the assisted inflationary scaling solution is the global late-time attractor for the parameter values for which the model is inflat

Andre Lukas, K. S. Stelle

We study the constraints on five-dimensional N=1 heterotic M-theory imposed by a consistent anomaly-free coupling of bulk and boundary theory. This requires analyzing the cancellation of triangle gauge anomalies on the four-dimensional orbifold planes due to anomaly inflow from the bulk. We find that the semi-simple part of the orbifold gauge groups and cert

B. A. Kniehl, A. A. Penin

In the framework of nonrelativistic QCD, we compute the leading double-logarithmic corrections of order alpha_s^3 ln^2(1/alpha_s) to the heavy-quark-antiquark bound-state wave function at the origin, which determines the production and annihilation rates of heavy quarkonia. The phenomenological implications for the top-antitop and Upsilon systems are discuss

P. K. Townsend

The relevance of calibrations, and `generalized&#39; calibrations, to supersymmetric M-brane configurations, and their associated field theories, is reviewed, with emphasis on applications to domain walls and domain wall junctions of D=4 N=1 supersymmetric field theories.

Jiri Chyla

QCD analysis of F_2^γ(x,Q^2) is revisited. It is emphasized that the presence of the inhomogeneous term in the evolution equations for quark distribution functions of the photon implies important difference in the way factorization mechanism works in photon-hadron and photon-photon collisions as compared to the hadronic ones. Moreover, a careful definitions

Everton M. C. Abreu, Marcelo Hott

We employ the Dirac-like equation for the gauge field proposed by Majorana to obtain an action that is symmetric under duality transformation. We also use the equivalence between duality and chiral symmetry in this fermion-like formulation to show how the Maxwell action can be seen as a mass term.

O. M. Bulashenko, J. M. Rubi, V. A. Kochelap

A self-consistent theory of shot noise in ballistic two-terminal conductors under the action of long-range Coulomb correlations is presented. Analytical formulas for the electron distribution function and its fluctuation along the conductor, which account for the Coulomb correlations, have been derived. Based upon these formulas, the current-noise reduction

S. Deser

We first present a review, intended for classical relativists, of the ultraviolet difficulties faced by local quantum gravity theories in both the usual Einstein versions and in their supergravity extensions, at least perturbatively. These problems, present in arbitrary dimensions, are traceable to the dimensionality of the Einstein constant. We then summari

Anthony Chefles

We derive a necessary condition for the existence of a completely-positive, linear, trace-preserving map which deterministically transforms one finite set of pure quantum states into another. This condition is also sufficient for linearly-independent initial states. We also examine the issue of quantum coherence, that is, when such operations maintain the pu

K. -H. Rehren

Canonical tensor product subfactors (CTPS&#39;s) describe, among other things, the embedding of chiral observables in two-dimensional conformal quantum field theories. A new class of CTPS&#39;s is constructed some of which are associated with certain modular invariants, thereby establishing the expected existence of the corresponding two-dimensional theories

Chong-Sun Chu, Pei-Ming Ho, Miao Li

D0-branes moving in a constant antisymmetric C field are found to be described by quantum mechanics of the supersymmetric matrix model with a similarity transformation. Sometimes this similarity transformation is singular or ill-defined and cannot be ignored. As an example, when there are non-vanishing C_{-ij} components, we obtain the theory for Dp-branes w

T. Padmanabhan

Several issues related to the gravitational clustering of collisionless dark matter in an expanding universe is discussed. The discussion is pedagogical but the emphasis is on semianalytic methods and open questions - rather than on well established results.

J. L. Diaz Cruz, D. A. Lopez Falcon

We study the contribution of charged Higgs boson to the rare decay of the top quark t->q+WZ (q=d,s,b) in models with Higgs sector that includes doublets and triplets. Higgs doublets are needed to couple charged Higgs with quarks, whereas the Higgs triplets are required to generate the non-standard vertex HWZ at tree-level. It is found that within a model tha

Csaba Csaki, Michael Graesser, Lisa Randall, John Terning

We analyze the cosmology of the Randall-Sundrum model and that of compact brane models in general in the presence of a radius stabilization mechanism. We find that the expansion of our universe is generically in agreement with the expected effective four dimensional description. The constraint (which is responsible for the appearance of non-conventional cosm

Hindrik Jan Angerman, Eugene Shakhnovich

We study solutions of statistically neutral polyampholyte chains containing a large fraction of neutral monomers. It is known that, even if the quality of the solvent with respect to the neutral monomers is good, a long chain will collapse into a globule. For weakly charged chains, the interior of this globule is semi-dilute. This paper considers mainly thet

A. P. Protogenov, V. A. Verbus

We study integrals of motion for Hirota bilinear difference equation that is satisfied by the eigenvalues of the transfer-matrix. The combinations of the eigenvalues of the transfer-matrix are found, which are integrals of motion for integrable discrete models for the $A_{k-1}$ algebra with zero and quasiperiodic boundary conditions. Discrete analogues of th

S. Pakvasa, W. Simmons, X. Tata

We present some informal remarks on aspects of relativistic quantum computing.

M. N. Sergeenko

Quasiclassical solution of the three-dimensional Schredinger&#39;s equation is given. The existence of nonzero minimal angular momentum M_0 = \hbar /2 is shown, which corresponds to the quantum fluctuations of the angular momentum and contributes to the energy of the ground state.

A. D. Baute, I. L. Egusquiza, J. G. Muga, R. Sala-Mayato

The position-momentum quasi-distribution obtained from an Arthurs and Kelly joint measurement model is used to obtain indirectly an ``operational&#39;&#39; time-of-arrival (TOA) distribution following a quantization procedure proposed by Kochański and Wódkiewicz [Phys. Rev. A 60, 2689 (1999)]. This TOA distribution is not time covariant. The procedure is gen

Alexander S. Shumovsky, Alexander A. Klyachko

New effective operators, describing the photons with given polarization at given position with respect to a source are proposed. These operators can be used to construct the near and intermediate zones quantum optics. It is shown that the use of the conventional plane photons can lead to a wrong results for quantum fluctuations of polarization even in the fa

Maurice Kibler, Tidjani Négadi

The quantum algebra suq(2) is introduced as a deformation of the ordinary Lie algebra su(2). This is achieved in a simple way by making use of $q$-bosons. In connection with the quantum algebra suq(2), we discuss the q-analogues of the harmonic oscillator and the angular momentum. We also introduce q-analogues of the hydrogen atom by means of a q-deformation

C. Figueira de Morisson Faria, A. Fring, R. Schrader

We provide a systematic derivation of the scaling behaviour of various quantities and establish in particular the scale invariance of the ionization probability. We discuss the gauge invariance of the scaling properties and the manner in which they can be exploited as consistency check in explicit analytical expressions, in perturbation theory, in the Kramer

Alan R. Champneys, Boris A. Malomed

We report a rich spectrum of isolated solitons residing inside ({\it embedded } into) the continuous radiation spectrum in a simple model of three-wave spatial interaction in a second-harmonic-generating planar optical waveguide equipped with a quasi-one-dimensional Bragg grating. An infinite sequence of fundamental embedded solitons are found, which differ

Dmitry V. Skryabin, Alan R. Champneys, William J. Firth

We show that soliton excitation in intracavity downconversion naturally selects a strictly defined frequency difference between the signal and idler fields. In particular, this phenomenon implies that if the signal has smaller losses than the idler then its frequency is pulled away from the cavity resonance and the idler frequency is pulled towards the reson

Alan R Champneys, Boris A Malomed

The first theoretical results are reported predicting {\em moving} solitons residing inside ({\it embedded} into) the continuous spectrum of radiation modes. The model taken is a Bragg-grating medium with Kerr nonlinearity and additional second-derivative (wave) terms. The moving embedded solitons (ESs) are doubly isolated (of codimension 2), but, neverthele

Alan Champneys, Yuri S. Kivshar

We develop {\em the first analytical theory of multikinks} for strongly {\em dispersive nonlinear systems}, considering the examples of the weakly discrete sine-Gordon model and the generalized Frenkel-Kontorova model with a piecewise parabolic potential. We reveal that there are no $2π$-kinks for this model, but there exist {\em discrete sets} of $2πN$-kink

R. Bijker, A. Frank

The anharmonic vibrator and rotor regions in nuclei are investigated in the framework of the interacting boson model using an ensemble of random one- and two-body interactions. We find a predominance of L(P)=0(+) ground states, as well as strong evidence for the occurrence of both vibrational and rotational band structures. This remarkable result suggests th

M. Bender

A comparison of calculated and experimental Q_alpha values of superheavy even-even nuclei and a few selected odd-N nuclei is presented in the framework of the relativistic mean-field model with the parameterization NL-Z2. Blocking effects are found to be important for a proper description of Q_alpha of odd mass nuclei. The model gives a good overall descript

D. H. Lu, S. N. Yang, A. W. Thomas

The violation of the scaling law for the electric and magnetic form factors of the proton are examined within the cloudy bag model. The suppression of the ratio of the electric and magnetic form factors is natural in the bag model. The pion cloud plays a moderate role in understanding the recent data from TJNAF.

Elliott H. Lieb, Robert Seiringer, Jakob Yngvason

In the theoretical description of recent experiments with dilute Bose gases confined in external potentials the Gross-Pitaevskii equation plays an important role. Its status as an approximation for the quantum mechanical many-body ground state problem has recently been rigorously clarified. A summary of this work is presented here.