January 2000 arXiv papers

A. De Rujula, A. Donini, M. B. Gavela, S. Rigolin

Gravitons could permeate extra space dimensions inaccessible to all other particles, which would be confined to ``branes''. We point out that these branes could be ``fat'' and have a non-vanishing width in the dimensions reserved for gravitons. In this case the other particles, confined within a finite width, should have ``branon'' ex

Anton Andreev, Alex Kamenev

We consider quantum statistics of charge transmitted through a mesoscopic device in the adiabatic pumping process. A general formula for the distribution function of the transmitted charge in terms of the time-dependent S-matrix is obtained. It is applied to a few simple examples of the pumping cycles. We identify coherent pumping strategies which lead to th

Eric R. Bittner

In this paper we compute quantum trajectories arising from Bohm's causal description of quantum mechanics. Our computational methodology is based upon a finite-element moving least-squares method (MWLS) presented recently by Wyatt and co-workers (Lopreore and Wyatt, Phys. Rev. Lett. {\bf 82}, 5190 (1999)). This method treats the "particles" in th

Fernando X. Villarruel, Benjamin E. Lauderdale, Daniel M. Mueth, Henrich M. Jaeger

We report on experiments to measure the temporal and spatial evolution of packing arrangements of anisotropic, cylindrical granular material, using high-resolution capacitive monitoring. In these experiments, the particle configurations start from an initially disordered, low-packing-fraction state and under vertical vibrations evolve to a dense, highly orde

J. M. Evans, M. Hassan, N. J. MacKay, A. J. Mountain

Conserved and commuting charges are investigated in both bosonic and supersymmetric classical chiral models, with and without Wess-Zumino terms. In the bosonic theories, there are conserved currents based on symmetric invariant tensors of the underlying algebra, and the construction of infinitely many commuting charges, with spins equal to the exponents of t

A. E. Bragg, L. J. Greenhill, J. M. Moran, C. Henkel

The water masers in NGC4258 delineate the structure and dynamics of a sub-parsec-diameter accretion disk around a supermassive black hole. We report acceleration measurements for 12 systemic-velocity spectral features and 19 high-velocity spectral features, using a total of 25 epochs of observations from Effelsberg (5 epochs), the VLA (15 epochs), and the VL

Anthony Sudbery

We study invariants of three-qubit states under local unitary transformations, i.e. functions on the space of entanglement types, which is known to have dimension 6. We show that there is no set of six independent polynomial invariants of degree less than or equal to 6, and find such a set with maximum degree 8. We describe an intrinsic definition of a canon

P. Massey, M. Guerrieri, R. R. Joyce

We use the number of papers published in 1998 and 1999 to test the hypothesis that the queue observing mode at WIYN leads to a significantly higher scientific throughput than classical mode observing. We use the papers published from the 4-m, and papers published from the non-queue WIYN time as controls, requiring only that the data be obtained after 1996 Au

Charles F. Gammie, Jeremy Goodman, Gordon I. Ogilvie

We consider the stability of warping modes in Keplerian discs. We find them to be parametrically unstable using two lines of attack, one based on three-mode couplings and the other on Floquet theory. We confirm the existence of the instability, and investigate its nonlinear development in three dimensions, via numerical experiment. The most rapidly growing n

P. Fiziev, S. Yazadjiev, T. Boyadjiev, M. Todorov

We study equilibrium configurations of boson stars in the framework of a class scalar-tensor theories of gravity with massive gravitational scalar (dilaton). In particular we investigate the influence of the mass of the dilaton on the boson star structure. We find that the masses of the boson stars in presence of dilaton are close to those in general relativ

Omer F. Dayi

Constrained hamiltonian structure of noncommutative gauge theory for the gauge group U(1) is discussed. Constraints are shown to be first class, although, they do not give an Abelian algebra in terms of Poisson brackets. The related BFV-BRST charge gives a vanishing generalized Poisson bracket by itself due to the associativity of *-product. Equivalence of n

B. Clerbaux, M. V. Polyakov

We fitted the pi-pi mass distribution in the range 0.5 < mpipi < 1.1 GeV measured in hard exclusive positron-proton reactions at HERA by the form dictated by QCD at leading twist level. Extracted parameters are related to valence quark distribution in the pion, and to the pion and rho meson distribution amplitudes. We obtain, for the first time, a measuremen

Michael Thorwart, Peter Reimann, Peter Hänggi

We consider the Brownian motion of a quantum mechanical particle in a one-dimensional parabolic potential with periodically modulated curvature under the influence of a thermal heat bath. Analytic expressions for the time-dependent position and momentum variances are compared with results of an iterative algorithm, the so-called quasiadiabatic propagator pat

P. West

The theory of non-linear realizations is used to derive the dynamics of the branes of M theory. A crucial step in this procedure is to use the enlarged automorphism group of the supersymmetry algebra recently introduced. The field strengths of the worldvolume gauge fields arise as some of the Goldstone fields associated with this automorphism group. The rela

Floris F. S. van der Tak, Ewine F. van Dishoeck, Neal J. Evans, Geoffrey A. Blake

The physical structure of the envelopes around a sample of fourteen massive (1000-100,000 solar L) young stars is investigated on 100- 100,000 AU scales using maps and spectra in submillimeter continuum and lines of C17O, CS and H2CO. The total column densities and the temperature profiles are obtained by fitting self-consistent dust models to submillimeter

L. Angelini, F. De Carlo, C. Marangi, M. Pellicoro

A new approach to clustering, based on the physical properties of inhomogeneous coupled chaotic maps, is presented. A chaotic map is assigned to each data-point and short range couplings are introduced. The stationary regime of the system corresponds to a macroscopic attractor independent of the initial conditions. The mutual information between couples of m

T. Xiang, W. N. Hardy

The anisotropy in the temperature dependence of the in-plane and c-axis conductivities of high-T_c cuprates in the superconducting state is shown to be consistent with a strong in-plane momentum dependence of both the quasiparticle scattering rate and the interlayer hopping integral. Applying the cold spot scattering model recently proposed by Ioffe and Mill

A. Baca, C. Garcia-Recio, J. Nieves

Using a microscopic antikaon-nucleus optical potential recently developed by Ramos and Oset (nucl-th/9906016, in print in Nuclear Physics A) from a chiral model, we calculate strong interaction shifts and widths for $K^-$ atoms. This purely theoretical potential gives an acceptable description of the measured data ($χ^2/{\rm num.data}= 3.8$), though it turns

Nima Arkani-Hamed, Savas Dimopoulos, Nemanja Kaloper, Raman Sundrum

We propose a new approach to the Cosmological Constant Problem which makes essential use of an extra dimension. A model is presented in which the Standard Model vacuum energy ``warps&#39;&#39; the higher-dimensional spacetime while preserving 4D flatness. We argue that the strong curvature region of our solutions may effectively cut off the size of the extra

Karyn Le Hur

We study two different metal-insulating transitions possibly occurring in one-dimensional Kondo lattices. First, we show how doping the pure Kondo lattice model in the strong-coupling limit, results in a Pokrovsky-Talapov transition. This produces a conducting state with a charge susceptibility diverging as the inverse of the doping, that seems in agreement

Machiko Hatsuda, Makoto Sakaguchi

The Green-Siegel central extension of superalgebras for BPS branes is studied. In these cases commutators of usual bosonic brane charges only with the broken supersymmetry charges allow this central extension. We present an interpretation of these fermionic central charges as fermionic brane charges, and show that they take nonzero values for a nontrivial fe

Rong-Gen Cai, Nobuyoshi Ohta

We study properties of (D$(p-2)$, D$p$) nonthreshold bound states ($2 \le p \le 6 $) in the dual gravity description. These bound states can be viewed as D$p$-branes with a nonzero NS $B$ field of rank two. We find that in the decoupling limit, the thermodynamics of the $N_p$ coincident D$p$-branes with $B$ field is the same not only as that of $N_p$ coincid

M. Ito, T. Matsuoka

In the context of the weakly coupled heterotic string, we propose a new model of mediating supersymmetry breaking. The breakdown of supersymmetry in the hidden sector is transmitted to anti-generation fields via gravitational interactions. Subsequent transmission of the breaking to the MSSM sector occurs via gauge interactions. It is shown that the mass spec

M. Jezabek, T. Nagano, Y. Sumino

We study how to probe the anomalous CP-violating couplings of top quark with photon, Z and gluon in the ttbar threshold region at future e+e- colliders. These couplings contribute to the difference of the t and tbar polarization vectors delta P and to the CP-odd spin correlation tensor delta Q_ij. We find that typical sizes of delta P and delta Q_ij are 5-20

Y. S. Myung, H. W. Lee

In the dilatonic domain wall model, we study the Schwarzschild black hole as a solution to the Kaluza-Klein (KK) zero mode effective action which is equivalent to the Brans-Dicke (BD) model with a potential. This can describe the large Randall-Sundrum (RS) black hole whose horizon is to be the intersection of the black cigar with the brane. The black cigar l

Toshihiko Ono

This letter proposes a new scenario to solve the structural or conceptual problems remained in quantum mechanics, and gives an overview of the theory proposed in quant-ph/9906130 (including quant-ph/9909025 and quant-ph/0001015).

H. M. Wiseman, K. Molmer

We analyze signal coherence in the setup of Wang, Zou and Mandel, where two optical downconverters have indistinct idler modes. Quantum interference, caused by indistinguishability of paths, has a visibility proportional to the transmission amplitude between idlers. Classical interference, caused by induced emission, may be complete for any finite transmissi

L. You

We investigate theoretical decoherence effects of the motional degrees of freedom of a single trapped atomic/ionic electronically coded qubit. For single bit rotations from a resonant running wave laser field excitation, we found the achievable fidelity to be determined by a single parameter characterized by the motional states. Our quantitative results prov

A. Saito, K. Kioi, Y. Akagi, N. Hashizume

We found that the actual computational time-cost of the QFT is O(n 2^n) for large n in a quantum computer using nuclear spins. The computational cost of a quantum algorithm has usually been estimated as the sum of the universal gates required in such ideal mathematical models as the Quantum Turing Machine(QTM) and the quantum circuit. This cost is proportion

Stephan I. Tzenov

We study the longitudinal motion of beam particles under the action of a single resonator wave induced by the beam itself. Based on the method of multiple scales we derive a system of coupled amplitude equations for the slowly varying part of the longitudinal distribution function and for the resonator wave envelope, corresponding to an arbitrary wave number

V. Kurasov

A new simple method for the first order phase transition kinetics is suggested. The metastable phase consumption can be imagined in frames of the modisperse approximation for the distribution of the droplets sizes. In all situations of the metastable phase decay this approximation leads to negligible errors in the total number of droplets appeared in the sys

Giovanni Gallavotti

We present a review of the chaotic hypothesis and discuss its applications to intermittency in statistical mechanics and fluid mechanics proposing a quantitative definition. Entropy creation rate is interpreted in terms of certain intermittency phenomena. An attempt to a theory of the experiment of Ciliberto-Laroche on the fluctuation law is presented.

N. A. Zabotin, H. A. Mityakov, G. P. Komrakov, V. L. Frolov

The results of experimental and theoretical study of anomalous attenuation of probe extraordinary waves in experiments on modification of ionosphere by powerful HF waves on &#34;Sura&#34; heating facility are presented. The experimental data indicate significant attenuation of extraordinary waves which can be explained as a result of multiple scattering of e

P. Maris, C. D. Roberts, S. M. Schmidt, P. C. Tandy

Inhomogeneous pseudoscalar and scalar Bethe-Salpeter equations solved using a renormalisation-group-improved rainbow-ladder truncation exhibit bound state poles below and above T_c, the critical temperature for chiral symmetry restoration. Above T_c the bound state amplitudes are identical, as are the positions and residues of the pseudoscalar and scalar pol

Yu. B. Ivanov, J. Knoll, H. Van Hees, D. N. Voskresensky

The effects of the propagation of particles which have a finite life-time and an according width in their mass spectrum are discussed in the context of transport descriptions. In the first part the coupling of soft photon modes to a source of charged particles is studied in a classical model which can be solved completely in analytical terms. The solution co

E. E. Kolomeitsev, D. N. Voskresensky

Particle-hole modes with quantum numbers of pions and negative kaons can propagate in nuclear matter. We discuss possible manifestations of these modes in experiments on heavy-ion collisions and on neutrino-nucleus scattering. Calculations of reaction rates in medium can be harmed by double counting, which arises because the very same quantum numbers can be

M. V. Ivanov, A. N. Antonov, M. K. Gaidarov

The main characteristics of the ground and, in particular, the first excited monopole state in the $^{4}$He, $^{16}$O and $^{40}$Ca nuclei are studied within the generator coordinate method using Skyrme-type effective forces and three construction potentials, namely the harmonic-oscillator, the square-well and Woods-Saxon potentials. Calculations of density

Peter Mohr

alpha-nucleus potentials are one important ingredient for the understanding of the nucleosynthesis of heavy neutron-deficient p nuclei in the astrophysical gamma-process where these p nuclei are produced by a series of (gamma,n), (gamma,p), and (gamma,alpha) reactions. I present an improved alpha-nucleus potential at the astrophysically relevant sub-Coulomb

Chun Wa Wong

The unpolarized cross section for the electroproduction of the isoscalar $J^π= 3^+$ di-delta dibaryon $d^*$ is calculated for deuteron target using a simple picture of elastic electron-baryon scattering from the $ΔΔ(^7D_1)$ and the $NN (^3S_1)$ components of the deuteron. The calculated differential cross section at the electron lab energy of 1 GeV has the v

G. Ambika, N. V. Sujatha

We present a graphical analysis of the mechanisms underlying the occurrences of bubbling sequences and bistability regions in the bifurcation scenario of a special class of one dimensional two parameter maps. The main result of the analysis is that whether it is bubbling or bistability is decided by the sign of the third derivative at the inflection point of

M. A. Manna

A new nonlinear equation governing asymptotic dynamics of ripples is derived by using a short wave perturbative expansion on a generalized version of the Green-Naghdi system. It admits peakon solutions with amplitude, velocity and width in interrelation and static compacton solutions with amplitude and width in interrelation. Short wave pattern formation is

C. N. Leung, J. A. Murakowski

A novel application of the Pade approximation is proposed in which the Pade approximant is used as an interpolation for the small and large coupling behaviors of a physical system, resulting in a prediction of the behavior of the system at intermediate couplings. This method is applied to quarkonium systems and reasonable values for the c and b quark masses

F. Hoevermann, H. Spohn, S. Teufel

We consider the dynamics generated by the Schroedinger operator $H=-{1/2}Δ+ V(x) + W(\epsi x)$, where $V$ is a lattice periodic potential and $W$ an external potential which varies slowly on the scale set by the lattice spacing. We prove that in the limit $\epsi \to 0$ the time dependent position operator and, more generally, semiclassical observables conver

S. A. Merkulov

This is a short comment on the Moyal formula for deformation quantization. It is shown that the Moyal algebra of functions on the plane is canonically isomorphic to an algebra of matrices of infinite size.

B. Enriquez, Y. Kosmann-Schwarzbach

We propose a formulation of the quantization problem of Manin quadruples, and show that a solution to this problem yields a quantization of the corresponding Poisson homogeneous spaces. We then solve both quantization problems in an example related to quantum spheres.

James Mc Laughlin

For each positive integer $n$ it is shown how to construct a finite collection of multivariable polynomials $\{F_{i}:=F_{i}(t,X_{1},..., X_{\lfloor \frac{n+1}{2} \rfloor})\}$ such that each positive integer whose squareroot has a continued fraction expansion with period $n+1$ lies in the range of exactly one of these polynomials. Moreover, each of these poly

G. Felder, Y. Markov, V. Tarasov, A. Varchenko

We define a system of &#34;dynamical&#34; differential equations compatible with the KZ differential equations. The KZ differential equations are associated to a complex simple Lie algebra $\mathbf{g}$. These are equations on a function of $n$ complex variables $z_i$ taking values in the tensor product of $n$ finite dimensional $\mathbf{g}$-modules. The KZ e

Yuri A. Kordyukov

We prove a Duistermaat-Guillemin trace formula for transversally elliptic operators on a compact foliated manifold.

L. Bonavero, S. Takayama

We prove finiteness of the number of smooth blow-downs on Fano manifolds and boundedness results for the geometry of non projective Fano-like manifolds. Our proofs use properness of Hilbert schemes and Mori theory.

Guillermo Cortiñas

Cuntz and Quillen have shown that for algebras over a field $k$ with $char(k)=0$, periodic cyclic homology may be regarded, in some sense, as the derived functor of (non-commutative) de Rham (co-)homology. The purpose of this paper is to formalize this derived functor analogy. We show that the localization ${Def}^{-1}\Cal{PA}$ of the category $\Cal{PA}$ of c

V. S. Alves, M. Gomes, S. L. V. Pinheiro, A. J. da Silva

We consider the model of a massless charged scalar field, in (2+1) dimensions, with a self interaction of the form $lambda (ϕ^* ϕ)^3$ and interacting with a Chern Simons field. We calculate the renormalization group $β$ functions of the coupling constants and the anomalous dimensions $γ$ of the basic fields. We show that the interaction with the Chern Simons

J. A. Lopez, J. Stephany

We discuss the formulation of spin observables associated to a non-relativistic spinning particles in terms of grassmanian differential operators. We use as configuration space variables for the pseudo-classical description of this system the positions $x$ and a Grassmanian vector $\vecε$. We consider an explicit discretization procedure to obtain the quantu

M. Chaichian, W. F. Chen, T. Kobayashi

Softly broken dual magnetic theory of N=1 supersymmetric SU(N_c) QCD with N_f flavours is investigated with the inclusion of trilinear coupling term of scalar fields in the case of N_f>N_c+1. It is found that the trilinear soft supersymmetric breaking term greatly change the phase and the vacuum structure.

Christos Kokorelis

We discuss the calculation of threshold corrections to gauge coupling constants for the, only, non-decomposable class of abelian (2, 2) symmetric N=1 four dimensional heterotic orbifold models, where the internal twist is realized as a generalized Coxeter automorphism. The latter orbifold was singled out in earlier work as the only N=1 heterotic $Z_N$ orbifo

I. Ya. Aref&#39;eva, D. M. Belov, A. S. Koshelev

Noncommutative quantum field theory of a complex scalar field is considered. There is a two-coupling noncommutative analogue of U(1)-invariant quartic interaction $(ϕ^*ϕ)^2$, namely $Aϕ^*\starϕ\starϕ^*\starϕ+ Bϕ^*\starϕ^*\starϕ\starϕ$. For arbitrary values of $A$ and $B$ the model is nonrenormalizable. However, it is one-loop renormalizable in two special ca

Zurab Kakushadze

We discuss geometry underlying orientifolds with non-trivial NS-NS B-flux. If D-branes wrap a torus with B-flux the rank of the gauge group is reduced due to non-commuting Wilson lines whose presence is implied by the B-flux. In the case of D-branes transverse to a torus with B-flux the rank reduction is due to a smaller number of D-branes required by tadpol

Shamit Kachru, Michael Schulz, Eva Silverstein

We present Poincare invariant domain wall (``3-brane&#39;&#39;) solutions to some 5-dimensional effective theories which can arise naturally in string theory. In particular, we find theories where Poincare invariant solutions exist for arbitrary values of the brane tension, for certain restricted forms of the bulk interactions. We describe examples in string

Matthias Neubert

These lectures provide an introduction to various topics in heavy-flavor physics. We review the theory and phenomenology of heavy-quark symmetry, exclusive weak decays of $B$ mesons, inclusive decay rates, and some rare $B$ decays.

J. D. Cohn, E. D. Stewart

Obtaining a potential flat enough to provide slow roll inflation is often difficult when gravitational effects are included. Non-abelian discrete gauge symmetries can guarantee the flatness of the inflaton potential in this case, and also provide special field values where inflation can end.

Tai-Fu Feng, Xue-Qian Li, Wen-Gan Ma, Xin-Min Zhang

We investigate the possibility of using accelarator beam particles to collide with the ambient neutralino dark matter particles in cosmic rays as a way to search for the cold dark matter. We study in detail its inelastic and elastic scattering with the projectile particles at electron-positron colliders and discuss the possible experimental signals and the r

Zuo-tang Liang, C. Boros

It has been realized for quite a long time that single-spin experiments, in which one of the colliding objects is transversely polarized, can be helpful in studying the properties of strong interaction in general and in testing Quantum Chromodynamics (QCD) in particular. Striking effects have been observed in the past few years which deviate drastically from

Zuo-tang Liang, C. Boros

We discuss Lambda polarization and single-spin left-right asymmetry in diffractive hadron-hadron scattering at high energies. We show that the physical picture proposed in a recent Letter is consistent with the experimental observation that $Λ$ polarization in the diffractive process, $pp\to ΛK^+p$, is much higher than that in the inclusive reaction, $pp\to

Esteban Roulet, Diego Harari, Silvia Mollerach

Several issues related to the lensing of ultra-high energy cosmic rays by the Galactic magnetic field are discussed.

V. A. Yerokhin

We present a numerical evaluation of the loop-after-loop contribution to the second-order self-energy for the ground state of hydrogenlike atoms with low nuclear charge numbers Z. The calculation is carried out in the Fried-Yennie gauge and without an expansion in Z α. Our calculation confirms the results of Mallampalli and Sapirstein and disagrees with the

T. Barnes

In this contribution I discuss recent developments in light meson spectroscopy, and note specific areas in which DAFNE is an especially appropriate tool for future experiments. One topic of special relevance is the spectroscopy of excited vector mesons; quite narrow vector hybrids are predicted by the flux-tube model, which could be produced by DAFNE when op

L. Hannelius, D. O. Riska

The chiral quark model describes the strangeness components of the light quarks as fluctuations into strange mesons and quarks. The single strange pseudoscalar and vector meson loop fluctuations of the constituent $u$- and $d$-quarks give rise to only very small strangeness form factors for the proton. This result is in line with recent experimental results,

Changhao Jin

The decay distribution of the kinematic variable ξ_u in inclusive charmless semileptonic decays of B mesons is unique. The novel method for a model-independent determination of |V_{ub}| is described.

Cai-Dian Lu

Using the generalized factorization approach, we calculate the CP asymmetries of charmless B decays. A number of decay channels has large CP asymmetries, which can be measured in the B factories.

Michael Gronau

We review several methods for determining the Kobayashi-Maskawa phase $γ={\rm Arg} V^*_{ub}$ from rate and CP asymmetry measurements in hadronic B decays. We focus on the processes $B\to DK, B_s\to D_s K$, and on charmless decays to two light pseudoscalars and decays to a pair of a pseudoscalar and a vector meson. Theoretical uncertainties underlying these m

E. Kh. Akhmedov

In the present lectures the following topics are considered: general properties of neutrinos, neutrino mass phenomenology (Dirac and Majorana masses), neutrino masses in the simplest extensions of the standard model (including the seesaw mechanism), neutrino oscillations in vacuum, neutrino oscillations in matter (the MSW effect) in 2- and 3-flavour schemes,

N. V. Hieu, H. N. Long, N. H. Son, N. A. Viet

The superconducting pairing of quarks induced by instantons in QCD is studied by means of the functional integral method. The integral equation determining the critical temperature of the superconducting phase transition is established. It is shown that the Bose condensate of diquarks consists of color antitriplet $(\bar{3}) $ scalar diquarks

M. A. Zubkov

We consider the Center projected SU(3) gluodynamics and rewrite it as a dual superconductor theory. The center monopole field plays the role of Higgs field in the dual superconductor theory. The center monopole creation operator is constructed.

Markus Elsing

ALEPH and DELPHI were the first experiments operating a silicon vertex detector at LEP. During the past 10 years of data taking the DELPHI Silicon Tracker was upgraded three times to follow the different tracking requirements for LEP 1 and LEP 2 as well as to improve the tracking performance. Several steps in the development of the pattern recognition softwa

Martin Rainer

We investigate up to which extend the kinematic setting of loop quantum gravity can be fit into a diffeomorphism invariant setting of algebraic QFT generalizing the Haag-Kastler setting of Wightman type QFT. The net of local (Weyl-)algebras resulting from a spin network state of quantum geometry immediately accommodates isotony and diffeomorphism covariance,

Yutaka Hosotani, Jefferson Bjoraker

In the pure Einstein-Yang-Mills theory in four dimensions there exist monopole and dyon solutions. The spectrum of the solutions is discrete in asymptotically flat or de Sitter space, whereas it is continuous in asymptotically anti-de Sitter space. The solutions are regular everywhere and specified with their mass, and non-Abelian electric and magnetic charg

David Olson, Glenn D. Starkman

The notion that the topology of the universe need not be that of the universal covering space of its geometry has recently received renewed attention. Generic signatures of cosmological topology have been sought, both in the distribution of objects in the universe, and especially in the temperature fluctuations of the cosmic microwave background radiation (C

C. Barrabes, V. Frolov, R. Parentani

We study the propagation of null rays and massless fields in a black hole fluctuating geometry. The metric fluctuations are induced by a small oscillating incoming flux of energy. The flux also induces black hole mass oscillations around its average value. We assume that the metric fluctuations are described by a statistical ensemble. The stochastic variable

Lada A. Adamic, Bernardo A. Huberman

A recent paper &#34;Emergence of scaling in random networks&#34; (cond-mat/9910332) by Barabasi and Albert proposes a growth mechanism to produce a stationary scale free distribution of the number of edges per node in large networks such as the Web. The Barabasi-Albert model predicts that older vertices acquire new edges at the expense of younger ones, givin

Luis A. Nunes Amaral, Antonio Scala, Marc Barthelemy, H. Eugene Stanley

Small-world networks are the focus of recent interest because they appear to circumvent many of the limitations of either random networks or regular lattices as frameworks for the study of interaction networks of complex systems. Here, we report an empirical study of the statistical properties of a variety of diverse real-world networks. We present evidence

J. W. Lynn, B. Keimer, C. Ulrich, C. Bernhard

Neutron diffraction has been used to study the magnetic order in RuSr{2}GdCu2O8. The Ru moments order antiferromagnetically at T{N}=136(2)K, coincident with the previously reported onset of ferromagnetism. Neighboring spins are antiparallel in all three directions, with a low T moment of 1.18(6) mu {B} along the c-axis. Our measurements put an upper limit of

M. Brodsky, N. B. Zhitenev, R. C. Ashoori, L. N. Pfeiffer

Using Single Electron Capacitance Spectroscopy, we study electron additions in quantum dots containing two potential minima separated by a shallow barrier. Analysis of addition spectra in magnetic field allows us to distinguish whether electrons are localized in either potential minimum or delocalized over the entire dot. We demonstrate that high magnetic fi

Michael E. Flatté

The recently observed properties of quasiparticle resonant states near impurities on the surface of superconducting BSCCO demonstrate that in-plane Andreev processes are either absent or phase-incoherent. Analysis of the spectral and spatial details of the electronic structure near a Zn impurity also suggest an effective magnetic component of the impurity po

F. K. Wilhelm, A. A. Golubov

We investigate the properties of complex mesoscopic superconducting-normal hybrid devices, Andreev-Interferometers in the case, where the current is proped through a superconducting tunneling contact whereas the proximity effect is generated by a transparent SN-interface. We show within the quasiclassical Green&#39;s functions technique, how the fundamental

P. Degiovanni, S. Peysson

Schrodinger cat states built from quantum superpositions of left or right Luttinger fermions located at different positions in a spinless Luttinger liquid are considered. Their decoherence rates are computed within the bosonization approach using as environments the quantum electromagnetic field or two or three dimensionnal acoustic phonon baths. Emphasis is

Hideo Yoshioka, Masahisa Tsuchiizu, Yoshikazu Suzumura

A one-dimensional electron system at quarter-filling has been examined by applying the renormalization group method to a bosonized model with on-site (U) and nearest-neighbor (V) repulsive interactions. By evaluating both normal scattering and Umklapp scattering perturbatively, we obtain a phase diagram in which a metallic state with a 2k_F spin density wave

M. Khenner, A. Averbuch, M. Israeli, M. Nathan

A numerical investigation of grain-boundary grooving by means of a Level Set method is carried out. An idealized polygranular interconnect which consists of grains separated by parallel grain boundaries aligned normal to the average orientation of the surface is considered. The surface diffusion is the only physical mechanism assumed. The surface diffusion i

Yu. M. Zinoviev

The correlation functions are calculated for the two dimensional Ising model with free boundary conditions and the two dimensional Ising model with periodic boundary conditions.

V. I. Yukalov, S. Gluzman

An analytical method is advanced for constructing interpolation formulae for complicated problems of statistical mechanics, in which just a few terms of asymptotic expansions are available. The method is based on the self-similar approximation theory, being its variant where control functions are defined from asymptotic crossover conditions. Several examples

H. Nojiri, S. Luther, M. Isobe, Y. Ueda

A significant frequency dependence of the ESR line width is found in NaV_2O_5 between 34-100 K and the line width increases as the resonance frequency is increased from 95 GHz to 760 GHz. The observed frequency dependence is qualitatively explained in terms of the dynamical charge disproportionation. The present results show the essential role of the interna

Leonardo Angelini, Mario Pellicoro, Sebastiano Stramaglia

We present some result about phase separation in coupled map lattices with additive noise. We show that additive noise acts as an ordering agent in this class of systems. In particular, in the weak coupling region, a suitable quantity of noise leads to complete ordering. Extrapolating our results at small coupling, we deduce that this phenomenon could take p

R. M. Wiessner, A. Fledderjohann, K. -H. Muetter, M. Karbach

We study the magnetisation process of the one dimensional spin-1/2 antiferromagnetic Heisenberg model with modulated couplings over j=1,2,3 sites. It turns out that the evolution of magnetisation plateaus depends on j and on the wave number q of the modulation according to the rule of Oshikawa, et al. A mapping of two- and three-leg zig-zag ladders on one di

N. B. Ivanov

Within the Dyson-Maleev boson formalism, we study the zero-temperature magnon dispersions in a family of one-dimensional quantum Heisenberg ferrimagnets composed of two different spins $(S_1,S_2)$ in the elementary cell. It is shown that the spin-wave theory can produce precise quantitative results for the low-energy excitations. The spin-stiffness constant

Massimo Campostrini, Andrea Pelissetto, Paolo Rossi, Ettore Vicari

We address the problem of determining the critical equation of state of three-dimensional XY systems. For this purpose we first consider the small-field expansion of the effective potential (Helmholtz free energy) in the high-temperature phase. We compute the first few nontrivial zero-momentum n-point renormalized couplings, which parametrize such expansion,

G. M. Kavoulakis, A. Mysyrowicz

In view of the recent experiments of O&#39;Hara, et al. on excitons in Cu_2O, we examine the interconversion between the angular-momentum triplet-state excitons and the angular-momentum singlet-state excitons by a spin-exchange process which has been overlooked in the past. We estimate the rate of this particle-conserving mechanism and find a substantially h

T. Jarlborg

Spin-polarized band calculations for LaSr_7B_{48} show a weak ferro-magnetic state. This is despite a low density-of-states (DOS) and a low Stoner factor. The reason for the magnetic state is found to be associated with a gain in potential energy in addition to the exchange energy, as a spin-splitting is imposed. An impurity like La DOS is essential for this

Kestutis Staliunas

It is shown, that Bose-Einstein condensation can occur not only in spatially extended equilibrium systems, but also in the systems far from thermal equilibrium, which show order-disorder phase transition. The investigation is performed by solving the Complex Ginzburg-Landau equation, a universal model for nonequilibrium order-disorder phase transitions.

J. S. Thakur, D. Neilson

We show that the metal to insulator transition, whether generated by decreasing the electron density or by increasing the spin alignment, is determined by a universal functional form of the two-electron correlation function g(r). This result provides direct evidence of the central role of the Coulomb repulsion and exchange in driving the metal-insulator tran

D. Sornette

Are large scale research programs that include many projects more productive than smaller ones with fewer projects? This problem of economy of scale is particularly relevant for understanding recent mergers in particular in the pharmaceutical industry. We present a quantitative theory based on the characterization of distributions of discounted sales S resul

Lloyd Wallace, Michael R. Meyer, Kenneth Hinkle, Suzan Edwards

We present a catalog of J-band spectra for 88 fundamental MK standard stars observed at a resolving power of R ~ 3000. This contribution serves as a companion atlas to the K-band spectra published by Wallace and Hinkle (1997) and the H-band atlas of Meyer et al. (1998). We report data from 7400-9550 1/cm (1.05-1.34 microns) for stars of spectral types O7-M6

Piotr Popowski

I demonstrate that the two unexpected results in the local Universe: anomalous intrinsic (V-I)_0 colors of RR Lyrae stars and clump giants in the Galactic center, and very short distances to Magellanic Clouds inferred from clump giants, can be at least partially resolved with a modified coefficient of selective extinction A_V/E(V-I). With this modification,