July 1999 arXiv papers — page 24

D. Barrado y Navascues, C. P. Deliyannis, J. R. Stauffer

We have obtained high resolution spectra of $\sim$40 members of M35, determined the Lithium-T$_{\rm{eff}}$ morphology and the distribution of the rotational velocity for G and K stars, and compared them to those of the Pleiades and other well-known open clusters.

Daniela Calzetti

I review the characteristics of high redshift galaxies, with particular attention to the effects of dust obscuration on the observed light. Galaxies at redshift z~1 and at z>2 are discussed separately, as the accessible information for each redshift range are different. In the z<=1-2 redshift region, data on the H-alpha and mid/far-IR luminosity of the galax

Ravi K. Sheth, H. J. Mo, Giuseppe Tormen

The Press--Schechter, excursion set approach allows one to make predictions about the shape and evolution of the mass function of bound objects. It combines the assumption that objects collapse spherically with the assumption that the initial density fluctuations were Gaussian and small. While the predicted mass function is reasonably accurate at the high ma

A. J. Barger, L. L. Cowie, E. A. Richards

Identifying the optical/near-infrared (NIR) counterparts to the distant submillimeter (submm) source population has proved difficult due to poor submm spatial resolution. However, the proportionality of both centimeter and submm data to the star formation rate suggests that high resolution radio continuum maps with subarcsecond positional accuracy could be e

Erik van Nimwegen, James P. Crutchfield

We analytically study the dynamics of evolving populations that exhibit metastability on the level of phenotype or fitness. In constant selective environments, such metastable behavior is caused by two qualitatively different mechanisms. One the one hand, populations may become pinned at a local fitness optimum, being separated from higher-fitness genotypes

D. S. Berman, Maulik K. Parikh

We probe the AdS/CFT correspondence by comparing the thermodynamics of a rotating black hole in five-dimensional anti-de Sitter space with that of a conformal field theory on $S^3$, whose parameters come from the boundary of spacetime. In the high temperature limit, we find agreement between gauge theory and gravity in all thermodynamic quantities upto the s

Maulik K. Parikh, Frank Wilczek

We present a short and direct derivation of Hawking radiation as a tunneling process, based on particles in a dynamical geometry. The imaginary part of the action for the classically forbidden process is related to the Boltzmann factor for emission at the Hawking temperature. Because the derivation respects conservation laws, the exact spectrum is not precis

M. P. Anantram, T. R. Govindan

We study electron transport between capped carbon nanotubes and a substrate, and relate the transmission probability to the local density of states in the cap. Our results show that the transmission probability mimics the behavior of the density of states at all energies except those that correspond to localized states in the cap. Close proximity of a substr

Yun Wang

Many astrophysical systems can be approximated as isothermal spheres. In an isothermal sphere, the ``foreground'' objects can act as lenses on ``background'' objects in the same distribution. We study gravitational lensing by a singular isothermal sphere analytically. Our results may have interesting applications.

J. A. Belinchon

The behavior of the constants, G,c,h,a,e,m and Lambda, considering them as variable, in the framework of a flat cosmological model with FRW symmetries described by a bulk viscous fluid and considering mechanisms of adiabatic matter creation are investigated. Within two models; one with radiation predominance and another of matter predominance, this behavior

Howard Baer, Marco A. Diaz, Javier Ferrandis, Xerxes Tata

We examine the spectrum of superparticles obtained from the minimal SO(10) grand unified model, where it is assumed the gauge symmetry breaking yields the Minimal Supersymmetric Standard Model (MSSM) as the effective theory at $M_{GUT}\sim 2\times 10^{16}$ GeV. In this model, unification of Yukawa couplings implies a value of $\tan\beta\sim 45-55$. At such h

Z. Kaufmann, A. Németh, P. Szépfalusy

One-dimensional maps exhibiting transient chaos and defined on two preimages of the unit interval [0,1] are investigated. It is shown that such maps have continuously many conditionally invariant measures $μ_σ$ scaling at the fixed point at x=0 as $x^σ$, but smooth elsewhere. Here $σ$ should be smaller than a critical value $σ_{c}$ that is related to the spe

E. S. Bozin, G. H. Kwei, H. Takagi, S. J. L. Billinge

We present local structural evidence supporting the presence of charge inhomogeneities in the CuO2 planes of underdoped La2-xSrxCuO4. High-resolution atomic pair distribution functions have been obtained from neutron powder diffraction data over the range of doping 0 < x < 0.30 at 10 K. Despite the average structure getting less orthorhombic we see a broaden

Ernesto Migliore

The measurements of the forward-backward asymmetry in Z -> c cbar and Z -> b bbar decays are among the most precise determinations of sin^2(theta)_W. In this paper the results obtained by the DELPHI experiment at LEP with three different analyses are reviewed together with the impact of the combined LEP result on the global Electroweak fit.

D. Mihailovic, V. V. Kabanov, K. Zagar, J. Demsar

A systamatic quantitative comparison of &#39;&#39;pseudogap&#39;&#39; values obtained from the analysis of charge and spin excitation spectroscopies in underdoped YBa2Cu3O7-x using a temperature-independent gap shows two distinct excitations, one visible in spin-flip spectroscopies like NMR and spin polarized neutron scattering, and the other in charge excit

G. M. Cicuta, M. Contedini, L. Molinari

We study a class of tridiagonal matrix models, the "q-roots of unity" models, which includes the sign ($q=2$) and the clock ($q=\infty$) models by Feinberg and Zee. We find that the eigenvalue densities are bounded by and have the symmetries of the regular polygon with $2 q$ sides, in the complex plane. Furthermore the averaged traces of $M^k$ are integers t

Boris Kors

We study nonperturbative aspects of asymmetric orbifolds of type IIA, focussing on models that allow a dual perturbative heterotic description. In particular we derive the boundary states that describe the nonsupersymmetric D-branes of the untwisted sector and their zero mode spectra. These we use to demonstrate, how some special non BPS multiplets are ident

Bohdan Grzadkowski, Jacek Pliszka

Determination of the top-quark Yukawa couplings in the process e+ e- -> t \bar{t} Z has been studied for the high luminosity option (\int L=500\fbinver) of a linear e+e- collider. Polarization of the electron beam has been considered. The method of optimal observables has been adopted to determine the couplings and to disentangle different models. It has bee

Klaus Behrndt, Eric Bergshoeff, Rein Halbersma, Jan Pieter van der Schaar

We investigate domain-wall/quantum field theory correspondences in various dimensions. Our general analysis does not only cover the well-studied cases in ten and eleven dimensions but also enables us to discuss new cases like a Type I/Heterotic 6-brane in ten dimensions and domain wall dualities in lower than ten dimensions. The examples we discuss include `

Shahar Hod

The destruction of the black-hole event horizon is ruled out by both cosmic censorship and the generalized second law of thermodynamics. We test the consistency of this prediction in a (more) `dangerous&#39; version of the gedanken experiment suggested by Bekenstein and Rosenzweig. A U(1)-charged particle is lowered {\it slowly} into a near extremal black ho

T. Miyakawa, K. Oda, T. Suzuki, H. Yabu

Static properties of a bose-fermi mixture of trapped potassium atoms are studied in terms of coupled Gross-Pitaevskii and Thomas-Fermi equations for both repulsive and attractive bose-fermi interatomic potentials. Qualitative estimates are given for solutions of the coupled equations, and the parameter regions are obtained analytically for the boson-density

Gilad Perez

We calculate the different contributions to the decay $K_{L}\to \pi ^{0}\nu \bar{\nu}$ that arise if the neutrinos are massive. In spite of a chiral enhancement factor, we find that these contributions are negligibly small. Compared to the CP violating leading contributions, the CP conserving contributions related to Dirac masses are suppressed by a factor o

P. K. Sahu, W. Cassing, U. Mosel, A. Ohnishi

We analyze the baryon sideward and elliptic flow from SIS (0.25 $\sim$ 2 A GeV) to AGS (2 $\sim 11.0A$GeV) energies for Au + Au collisions in the relativistic transport model RBUU that includes all baryon resonances up to a mass of 2 GeV as well as string degrees of freedom for the higher mass continuum. There are two factors which dominantly determine the b

M. Flanz, W. Rodejohann, K. Zuber

The lepton-number violating process ν_μN \to μ^- μ^+ μ^+ X is studied for the first time in connection with Majorana neutrino masses of the second generation. The sensitivity for light and heavy Majorana neutrinos is investigated. The ratio with respect to the standard model charged current process is improved by some orders of magnitude if compared to previ

F. Ghaboussi

We investigate the dimensional, the dynamical and the topological structures of four dimensional Einstein and Yang-Mills theories. It is shown that these theories are constructed from two dimensional quantities, so that they possess always a distinguished two dimensional substructure. In this sense the four dimensional field theories are equivalent to relate

Y. A. Yan, Y. L. Wu, W. Y. Wang

We apply the new formulation of heavy quark effective field theory (HQEFT) to the inclusive decays of bottom hadrons. The long-term ambiguity of using heavy quark mass or heavy hadron mass for inclusive decays is clarified within the framework of the new formulation of HQEFT. The $1/m_b$ order corrections are absent and contributions from $1/m_b^2$ terms are

A. S. Gevorkyan, A. A. Udalov

One-dimensional problem for quantum harmonic oscillator with &#34;regular+random&#34; frequency subjected to the external &#34;regular+random&#34; force is considered. Averaged transition probabilities are found.

J. Finkelstein

Deutsch has recently (in quant-ph/9906015) offered a justification, based only on the non-probabilistic axioms of quantum theory and of classical decision theory, for the use of the standard quantum probability rules. In this note, this justification is examined.

Noah Linden, Eriks Kupce, Ray Freeman

If NMR systems are to be used as practical quantum computers, the number of coupled spins will need to be so large that it is not feasible to rely on purely heteronuclear spin systems. The implementation of a quantum logic gate imposes certain constraints on the motion of those spins not directly involved in that gate, the so-called &#34;spectator&#34; spins

A. Lezama S. Barreiro A. Lipsich A. M. Akulshin

Spectroscopic features revealing the coherent interaction of a degenerate two-level atomic system with two optical fields are examined. A model for the numerical calculation of the response of a degenerate two-level system to the action of an arbitrarily intense resonant pump field and a weak probe in the presence of a magnetic field is presented. The model

Sibasish Ghosh, Guruprasad Kar, Anirban Roy

It is shown that no signaling constraint generates the whole class of 1 $\rightarrow$ 2 optimal quantum cloning machines of single qubits.

Siddhartha Sahi

Motivated by the work of Koornwinder, Macdonald, Cherednik, Noumi, and van Diejen we define a 6-parameter double affine Hecke algebra and establish its basic structural properties, including the existence of an involution. We relate the algebra to (symmetric and nonsymmetric) Koornwinder polynomials via the method of intertwiners and, as a consequence, obtai

G. N. Throumoulopoulos, H. Tasso

A recent study on axisymmetric ideal magnetohydrodynamic equilibria with incompressible flows [H. Tasso and G. N. Throumoulopoulos, Phys. Plasmas {\bf 5}, 2378 (1998)] is extended to the generic case of helically symmetric equilibria with incompressible flows. It is shown that the equilibrium states of the system under consideration are governed by an ellipt

L. De Santis, P. Carloni

In serine proteases (SP&#39;s), the H-bond between His-57 and Asp-102, and that between Gly-193 and the transition state intermediate play a crucial role for enzymatic function. To shed light on the nature of these interactions, we have carried out ab initio molecular dynamics simulations on complexes representing adducts between the reaction intermediate an

Gao Shan

Aiming at providing an objective picture for the collapse process of wave function during measurement, further analysis about the quantum discontinuous motion is presented, when considering general relativity we show that the new motion is essentially replaced by the quantum jump motion, which naturally results in the collapse process of the wave function. F

Gao Shan

Aiming at providing an objective motion picture for the microscopic object described by the wave function, new analysis about motion is presented by use of the point set theory in mathematics, through which we show that a new kind of motion named quantum discontinuous motion is the general motion mode of the particle, while classical continuous motion is jus

A. Ts. Amatuni

Interaction of external monochromatic, linearly polorized plane EM-wave with nonlinear one-dimensional wake wave, generated by relativistic electron bunch moving in cold plasma, is considered. At definite conditions on parameters of plasma and bunch, nonlinear wake wave can have a pronounced spikes, where plasma electron density has its maximum value and pla

J. L. Nagle, M. J. Bennett

We present a Glauber-based study of J/Psi and Drell-Yan yields in nucleus-nucleus collisions. Using this approach, we have investigated the impact of energy loss by the colliding nuclei on observed yields and transverse momentum spectra of J/Psi and Drell-Yan. These studies permit an assessment of the importance of initial state energy loss in relation to &#

M. K. Gaidarov, K. A. Pavlova, A. N. Antonov, M. V. Stoitsov

The cross sections of the ($e,e&#39;N$) and ($γ,p$) reactions on $^{16}$O are calculated, for the transitions to the $1/2^{-}$ ground state and the first $3/2^{-}$ excited state of the residual nucleus, using single-particle overlap functions obtained on the basis of one-body density matrices within different correlation methods. The electron-induced one-nuc

Y. Abe, K. Okazaki, Y. Aritomo, T. Tokuda

Dynamical reaction theories are reviewed for synthesis of superheavy elements. Characteristic features of formation and surviving are discussed with reference to possible incident channels. Theoretical predictions are presented on favorable incident channels and on optimum energies for synthesis of Z=114.

S. M. Lenzi, D. R. Napoli, C. A. Ur, D. Bazzacco

High spin states in the odd-odd N=Z nucleus 46V have been identified. At low spin, the T=1 isobaric analogue states of 46Ti are established up to I = 6+. Other high spin states, including the band terminating state, are tentatively assigned to the same T=1 band. The T=0 band built on the low-lying 3+ isomer is observed up to the 1f7/2-shell termination at I=

Philippe Chanfreau, Hannu Lyyjynen

This paper aims to cast some new light on controlling chaos using the OGY- and the Zero-Spectral-Radius methods. In deriving those methods we use a generalized procedure differing from the usual ones. This procedure allows us to conveniently treat maps to be controlled bringing the orbit to both various saddles and to sources with both real and complex eigen

Partha Guha, Mikhail Olshanetsky

In this paper we discuss a universal integrable model, given by a sum of two Wess-Zumino-Witten-Novikov (WZWN) actions, corresponding to two different orbits of the coadjoint action of a loop group on its dual, and the Polyakov-Weigmann cocycle describing their interactions. This is an effective action for free fermions on a torus with nontrivial boundary co

Larisa A. Khodarinova, I. A. Prikhodsky

Explicit algebraic relations between the quantum integrals of the elliptic Calogero--Moser quantum problems related to the root systems ${\bf A_2}$ and ${\bf B_2}$ are found.

Pavel Bleher, Alexander Its

We derive semiclassical asymptotics for the orthogonal polynomials P_n(z) on the line with respect to the exponential weight \exp(-NV(z)), where V(z) is a double-well quartic polynomial, in the limit when n, N \to \infty. We assume that ε\le (n/N) \le λ_{cr} - εfor some ε> 0, where λ_{cr} is the critical value which separates orthogonal polynomials with two

Jean-Marie Barbaroux, Werner Fischer, Peter Müller

We study dynamical properties of random Schrödinger operators $H^{(ω)}$ defined on the Hilbert space $\ell^2(\bbZ^d)$ or $L^2(\bbR^d)$. Building on results from existing multi-scale analyses, we give sufficient conditions on $H^{(ω)}$ to obtain the vanishing of the diffusion exponent $$ σ_{\rm diff}^+ := \limsup_{T\rightarrow\infty } \frac{\log \bbE \left(\l

R. Vilela Mendes

The algebras of non-relativistic and of classical mechanics are unstable algebraic structures. Their deformation towards stable structures leads, respectively, to relativity and to quantum mechanics. Likewise, the combined relativistic quantum mechanics algebra is also unstable. Its stabilization requires the non-commutativity of the space-time coordinates a

Boris A. Kupershmidt

If a classical $r$-matrix $r$ is skewsymmetric, its quantization $R$ can lose the skewsymmetry property. Even when $R$ is skewsymmetric, it may not be unique.

Anatoliy K. Prykarpatsky, Denis Blackmore

If we are given a smooth differential operator in the variable $x\in {\mathbb R}/2π{\mathbb Z},$ its normal form, as is well known, is the simplest form obtainable by means of the $\mbox{Diff}(S^1)$-group action on the space of all such operators. A versal deformation of this operator is a normal form for some parametric infinitesimal family including the op

Paul Bracken, Alfred M. Grundland

Analysis of the generalized Weierstrass-Enneper system includes the estimation of the degree of indeterminancy of the general analytic solution and the discussion of the boundary value problem. Several different procedures for constructing certain classes of solutions to this system, including potential, harmonic and separable types of solutions, are propose

Brian White

We prove (without using Federer&#39;s structure theorem) that a finite-mass flat chain over any coefficient group is rectifiable if and only if almost all of its 0-dimensional slices are rectifiable. This implies that every flat chain of finite mass and finite size is rectifiable. It also leads to a simple necessary and sufficient condition on the coefficien

Mikhail V. Safonov, Yu Yuan

We prove the doubling property of L-caloric measure corresponding to the second order parabolic equation in the whole space and in Lipschitz domains. For parabolic equations in the divergence form, a weaker form of the doubling property follows easily from a recent result, the backward Harnack inequality, and known estimates of Green&#39;s function. Our meth

Arvind Nair

M. Goresky, G. Harder, and R. MacPherson defined weighted cohomologies of arithmetic groups Γin a real group G, with coefficients in certain local systems, associated to arbitrary upper and lower weight profiles. The author shows, using essentially local arguments on the reductive Borel-Serre compactification, that these cohomologies agree with certain weigh

Sergei Merkulov, Lorenz Schwachhöfer

The subgroups of GL(n,R) that act irreducibly on R^n and that can occur as the holonomy of a torsion-free affine connection on an n-manifold are classified, thus completing the work on this subject begun by M. Berger in the 1950s. The methods employed include representation theory, the theory of hermitian symmetric spaces, twistor theory, and Poisson geometr

Shuhei Hayashi

There is a gap in the proof of Lemma VII.4 in [Ann. of Math. (2) 145 (1997), 81--137]. We present an alternative proof of Theorem B (C^1 Omega-stable vector fields satisfy Axiom A). The novel and essential part in the proof of the stability and Omega-stability conjectures for flows is the connecting lemma introduced previously. A mistake in the proof of the

Kevin Ford

An old conjecture of Sierpinski asserts that for every integer k \ge 2, there is a number m for which the equation ϕ(x)=m has exactly k solutions. Here ϕis Euler&#39;s totient function. In 1961, Schinzel deduced this conjecture from his Hypothesis H. The purpose of this paper is to present an unconditional proof of Sierpinski&#39;s conjecture. The proof uses

Laurent Clozel

In characteristic zero, it was proven a long time ago by D. Lieberman that cohomological and numerical equivalence coincide for cycles on abelian varieties. In this paper we show this to be true also in a somewhat technical sense for abelian varieties defined over a finite field. The technicality is that the result is valid for l-adic cohomology for primes l

Joseph Bernstein, Andre Reznikov

Properties of analytic vectors in representations of SL(2,R) are used to give new bounds for the triple products recently considered by P. Sarnak. A conjecture of Sarnak about such products is proved. The results of this paper generalize results of A. Good and M. Jutila about special cases, but the techniques are entirely different. One consequence of these

Vitaly Bergelson, Alexander Leibman

An abstract, Hales-Jewett type extension of the polynomial van der Waerden Theorem [J. Amer. Math. Soc. 9 (1996),725-753] is established: Theorem. Let r,d,q \in \N. There exists N \in \N such that for any r-coloring of the set of subsets of V={1,...,N}^{d} x {1,...,q} there exist a set a \subset V and a nonempty set γ\subseteq {1,...,N} such that a \cap (γ^{

J. Brian Conrey, Xian-Jin Li

Let E_lambda be a Hilbert space, whose elements are functions spanned by the eigenfunctions of the Laplace-Beltrami operator associated with an eigenvalue lambda>0. The norm of elements in this space is given by the Petersson inner product. In this paper, the trace of Hecke operators T_n acting on the space E_lambda is computed for congruence subgroups of Ga

R. -O. Buchweitz, S. Liu

We construct Artin algebras with vanishing first Hochschild Cohomology but a loop in their ordinary quiver. Some authors guessed earlier that such examples could not exist.

Armand Borel, Robert Friedman, John W. Morgan

We describe the components of the moduli space of conjugacy classes of commuting pairs and triples of elements in a compact Lie group. This description is in terms of the extended Dynkin diagram of the simply connected cover, together with the coroot integers and the action of the fundamental group. In the case of three commuting elements, we compute Chern-S

Daniele Guido, Tommaso Isola

In Alain Connes noncommutative geometry, the question of the existence of a non-trivial integral can be described in terms of the singular traceability of the compact operator |D|^(-d), D being the Dirac operator, namely of the existence of a finite non-trivial singular trace on the ideal generated by |D|^(-d). A condition on the non triviality of the Dixmie

R. -O. Buchweitz, H. Flenner

We construct a general semiregularity map for cycles on a complex analytic or algebraic manifold and show that such semiregularity map can be obtained from the classical tool of the Atiyah-Chern character. The first part of the paper is fairly detailed, deducing the existence and explicit form of a generalized semiregularity map from known results and constr

Pascal Koiran

We show that irreducibility is not a first-order definable property of real algebraic varieties. The proof is based on the recent o-minimality result for the exponential function. We conjecture that irreducibility is not a definable property of complex algebraic varieties.

János Kollár

Let X be a smooth, projective variety defined over a local field K. Following Manin, two K-points of X are called R-equivalent if they can be joined by a rational curve defined over K. The main result of this note shows that if there are only finitely many R-equivalence classes over the algebraic closure of K then the same holds over K. This also yields the

Wen-Fa Lu

Using the Gaussian wave-functional approach with the normal-ordering renormalization prescription, we show that for the (3+1)-dimensional massive lambda phi^4 theory, ``precarious&#39;&#39; and ``autonomous&#39;&#39; phi^4s can exist if and only if the normal-ordering mass is equal to the classical masses at the symmetrc and asymmetric vacua, respectively.

Maulik K. Parikh

This thesis addresses some classical and semi-classical aspects of black holes using an effective membrane representation of the event horizon. The classical &#34;membrane paradigm&#34; equations are derived from an underlying action formulation, even though the equations are dissipative. It is shown how the membrane action can also account for the hole&#39;

K. S. Babu, S. Nandi

We suggest a novel approach towards resolving the fermion mass hierarchy problem within the framework of the Standard Model. It is shown that the observed masses and mixings can be explained with order one couplings using successive higher dimensional operators involving the SM Higgs doublet field. This scenario predicts flavor-dependent enhancement in the t

J. C. Montero, V. Pleitez

We show that there is a general sort of models in which it is possible to have large magnetic dipole moments for neutrinos while keeping their masses arbitrarily small. Some examples of these models are considered.

Raju Venugopalan

Deeply inelastic scattering of electrons off nuclei can determine whether parton distributions saturate at HERA energies. If so, this phenomenon will also tell us a great deal about how particles are produced, and whether they equilibrate, in high energy nuclear collisions.

M. M. Musakhanov

It was shown by careful consideration of the time--dependent classic solution for the rotated skyrmion, that such solution at large distances has radiational component similar to the Lienart-Viehart retarded potential in Electrodynamics. We consider such solution as stationary phase configuration of the pion field in path integrals for the correlators of $n$

G. Belanger, F. Boudjema, T. Kon, V. Lafage

We calculate e+e- --> stop/stop/Z at a linear collider. For large splitting between the two stops the cross-section is sensitive to the value of m(stop2) when this particle is too heavy to be directly produced. The results are compared to e+e- --> stop/stop/h.

G. Auberson, G. Moultaka

Integrated forms of the one-loop evolution equations are given for the Yukawa couplings in the MSSM, valid for any value of $\tan β$, generalizable to virtually any number of Yukawa fermions, and including all gauge couplings. These forms turn out to have nice mathematical convergence properties which we prove, and we determine the ensuing convergence criter

S. Mrenna

The simple &#34;straw-man&#34; model of low-scale technicolor contains light color--singlet technihadrons, which mix with the electroweak gauge bosons. We present lepton collider production rates at the parton level, and show that experiments at LEP2 may be sensitive to the presence of technirho and techniomega states with masses 10-20 GeV beyond the center-

Aidan J. Keane, Richard K. Barrett

The Robertson-Walker spacetimes are conformally flat and so are conformally invariant under the action of the Lie group SO(4,2), the conformal group of Minkowski spacetime. We find a local coordinate transformation allowing the Robertson-Walker metric to be written in a manifestly conformally flat form for all values of the curvature parameter k continuously

David Garfinkle

This paper has been withdrawn by the author. It has come to my attention that most of the results reported here have already been obtained by Ludvigsen.

Naoto Nagaosa, Patrick A. Lee

The issue of confinement and bose condensation is studied for gauge models of high-Tc superconductors. First the Abelian-Higgs model in (2+1)D, i.e., XY-model coupled to lattice gauge field $a_μ$ with coupling $g$, is studied taking into account both the instantons and vortices. This model corresponds to integer filling of the bosons, and can be mapped to a

J. P. Holder, A. K. Savchenko, Vladimir I. Fal&#39;ko, B. Jouault

We have found that the local density of states fluctuations (LDOSF) in a disordered metal, detected using an impurity in the barrier as a spectrometer, undergo enhanced (with respect to SdH and dHvA effects) oscillations in strong magnetic fields, omega _cτ> 1. We attribute this to the dominant role of the states near bottoms of Landau bands which give the m

Kheya Sengupta, V. A. Raghunathan, John Katsaras

We have calculated the electron density maps of the ripple phase of dimyristoylphosphatidylcholine (DMPC) and palmitoyl-oleoyl phosphatidylcholine (POPC) multibilayers at different temperatures and fixed relative humidity. Our analysis establishes, for the first time, the existence of an average tilt of the hydrocarbon chains of the lipid molecules along the

R. Balian

Statistical mechanics relies on the complete though probabilistic description of a system in terms of all the microscopic variables. Its object is to derive therefrom static and dynamic properties involving some reduced set of variables. The elimination of the irrelevant variables is guided by the maximum entropy criterion, which produces the probability law

J. C. Lemm, J. Uhlig, A. Weiguny

A nonparametric Bayesian approach is developed to determine quantum potentials from empirical data for quantum systems at finite temperature. The approach combines the likelihood model of quantum mechanics with a priori information over potentials implemented in form of stochastic processes. Its specific advantages are the possibilities to deal with heteroge

T. P. C. van Noije, M. H. Ernst

A Cahn-Hilliard-type theory for hydrodynamic fluctuations is proposed that gives a quantitative description of the slowly evolving spatial correlations and structures in density and flow fields in the early stages of evolution of freely cooling granular fluids. Two mechanisms for pattern selection and structure formation are identified: unstable modes leadin

G. C. Ferrario, V. G. Benza

We determine the propagation properties of a quantum particle in a d-dimensional lattice with hopping disorder, delta-correlated in time. The system is delocalized: the averaged transition probability shows a diffusive behavior. Then, superimposed to the disorder, we consider a bias favouring the motion with a given orientation, as in the dynamics of flux li

Nicola Manini, Paolo De Los Rios

Due to the ubiquitous presence of a Berry phase, in most cases of dynamical Jahn-Teller systems the symmetry of the vibronic ground state is the same as that of the original degenerate electronic state. As a single exception, the linear H x h icosahedral model, relevant to the physics of C60 cations, is determined by an additional free parameter, which can b

Yoichi Ando, N. Miyamoto, Kouji Segawa, T. Kawata

The specific heat of (Na,Ca)Co_{2}O_{4} is measured at low-temperatures to determine the magnitude of the electronic specific-heat coefficient γ, in an attempt to gain an insight into the origin of the unusually large thermoelectric power of this compound. It is found that γis as large as 48 mJ/molK^2, which is an order of magnitude larger than γof simple me

Luis Brey

The dependence on temperature of the spin magnetization of a two-dimensional electron gas at filling factor unity is studied. Using classical Monte Carlo simulations we analyze the effect that the equivalence between topological and electrical charge has on the the behavior of the magnetization. We find that at intermediate temperatures the spin polarization

Akito Kobayashi, Atsushi Tsuruta, Tamifusa Matsuura, Yoshihiro Kuroda

Using the d-p model, we demonstrate that the pseudogap, which is induced by the superconducting fluctuation, plays key roles in the determination of the phase diagram observed in high-Tc superconducting materials. We take the pairing interaction mediated by the spin fluctuation and calculate the superconducting transition temperature Tc, the NMR relaxation r

C. Grimaldi

The effects of impurity and spin-orbit scattering potentials can strongly affect the Zeeman response of a d-wave superconductor. Here, both the phase diagram and the quasiparticle density of states are calculated within the Born approximation and it is found that the spin-orbit interaction influences in a qualitatively different way the Zeeman response of d-

K. L. Sebastian

We consider the generalization of the Kramers escape over a barrier problem to the case of a long chain molecule. It involves the motion of chain molecule of N segments across a region where the free energy per segment is higher, so that it has to cross a barrier. We use the Rouse model and find that the free energy of activation has a square root dependence

Steven M. Girvin

These pedagogical lecture notes present a general introduction to most aspects of the integer and fractional quantum Hall effects. This is followed by an extensive discussion of quantum Hall ferromagnetism, both for spins in single-layer systems and `pseudospins&#39; in double-layer systems. The effective field theories describing various broken symmetry sta

Y. Morita, Y. Hatsugai

Based on the two-dimensional lattice fermion model, we discuss transitions between different pairing states. Each phase is labeled by an integer which is a topological invariant and characterized by vortices of the Bloch wavefunction. The transitions between phases with different integers obey a selection rule. Basic properties of the edge states are reveale

B. N. Narozhny, I. L. Aleiner

We consider a diffusive S-N-S junction with electrons in the normal layer driven out of equilibrium by external bias. We show that, the non-equilibrium fluctuations of the electron density in the normal layer cause the fluctuations of the phase of the order parameter in the S-layers. As a result, the magnitude of the Josephson current in the non-equilibrium

Robert Haslinger, Robert Joynt

Conduction in bulk polycrystalline high-T$_c$ superconductors with relatively high critical currents has been shown to be percolative. This phenomenon is due to weak links at grain boundaries. These weak links are the major limiting factor for technological applications which require high current densities. We formulate a model of these materials which can b

Chigak Itoi, Hisamitsu Mukaida

We derive a new renormalization group to calculate a non-trivial critical exponent of the divergent correlation length which gives a universality classification of essential singularities in infinite-order phase transitions. This method resolves the problem of a vanishing scaling matrix. The exponent is obtained from the maximal eigenvalue of a scaling matri

A. C. Quillen, Gary A. Bower, M. Stritzinger

We present a NICMOS 1.6 micron imaging isophotal study of 27 early-type galaxies. Our selected sample is not as biased against dusty galaxies as the visible WFPC samples observed with HST. Core galaxies have reduced ellipticity and boxiness near and within their core or break radius. This supports a core formation mechanism which mixes or scatters stars such

Todor Stanev

We suggest an experimental measurement that could detect the appearance of the tau neutrinos in muon to tau neutrino oscillations of atmospheric neutrinos by measuring the energy spectra of neutrino induced showers. Tau neutrinos deposit a large fraction of their energy in showers generated in CC interactions and the subsequent tau--lepton decay. The appeara

J. Greiner, A. J. Castro-Tirado, Th. Boller, H. W. Duerbeck

We have performed a ROSAT follow-up observation of the X-ray transient SAX J1810.8-2609 on March 24, 1998 and detected a bright X-ray source (named RX J1810.7-2609) which was not detected during the ROSAT all-sky survey in September 1990. Optical-to-infrared follow-up observations of the 10 arcsec radius ROSAT HRI X-ray error box revealed one variable object

A. C. Quillen, M. Holman

During orbital migration of a giant extrasolar planet via ejection of planetesimals (Murray et al.~1998), inner mean motion resonances can be strong enough to cause planetesimals to graze or impact the star. We integrate numerically the motions of particles which pass through the 3:1 or 4:1 mean motion resonances of a migrating Jupiter mass planet. We find t

David J. Jeffery

The radioactive decay energy (RDE) deposition in supernovae from the decay chain Ni56-Co56-Fe56 usually directly powers the UV/optical/IR (UVOIR) bolometric luminosity of supernovae in their quasi-steady state phase until very late times. The result for this phase is exponential/quasi-exponential UVOIR bolometric light curves and often exponential/quasi-expo