February 2002 arXiv papers — page 21

Jae-Hyouk Lee, Naichung Conan Leung

This article studies the geometry of moduli spaces of G2-manifolds, associative cycles, coassociative cycles and deformed Donaldson-Thomas bundles. We introduce natural symmetric cubic tensors and differential forms on these moduli spaces. They correspond to Yukawa couplings and correlation functions in M-theory. We expect that the Yukawa coupling characteri

F. Caravaglios, P. Roudeau, A. Stocchi

Using a Monte Carlo method, we have directly extracted from the available measurements, the hierarchies among the different elements of the quark mass matrices. To do that, we have first introduced a model independent parameterization for two generic class of models: those based on Abelian symmetries and those inspired by a U(2) horizontal symmetry. So, matr

Andrew W. Blain, Tom Phillips

Submillimetre observations reveal a cosmologically significant population of high-redshift dust-enshrouded galaxies. The form of evolution inferred for this population can be reconciled easily with COBE FIRAS and DIRBE measurements of the cosmic background radiation (CBR) at wavelengths >100 microns. At shorter wavelengths, however, the 60-micron CBR intensi

Stephen D. Landy

A comparison of the galaxy pairwise velocity distribution functions determined from the three largest publicly available galaxy redshift surveys is presented. This is the first direct comparison of this function across these surveys using an identical method. It is found that the two r-band selected surveys, the LCRS (Las Campanas Redshift Survey) and the SD

D. F. Carvalho, M. E. Gomez, J. C. Romao

The simplest unified extension of the Minimal Supersymmetric Standard Model with bi-linear R-parity violation naturally predicts a hierarchical neutrino mass spectrum, suitable to explain atmospheric and solar neutrino fluxes. We study whether the individual violation of the lepton numbers L_{e,mu,tau} in the charged sector can lead to measurable rates for B

Roberto Balbinot, Alessandro Fabbri, Piero Nicolini, Patrick J. Sutton

We obtain an analytic approximation for the effective action of a quantum scalar field in a general static two-dimensional spacetime. We apply this to the dilaton gravity model resulting from the spherical reduction of a massive, non-minimally coupled scalar field in the four-dimensional Schwarzschild geometry. Careful analysis near the event horizon shows t

A. Robledo

We consider the period-doubling and intermittency transitions in iterated nonlinear one-dimensional maps to corroborate unambiguously the validity of Tsallis' non-extensive statistics at these critical points. We study the map $x_{n+1}=x_{n}+u| x_{n}| ^{z}$, $z>1$, as it describes generically the neighborhood of all of these transitions. The exact renorm

A. Filipcic, M. Horvat, D. Veberic, D. Zavrtanik

Measurements of the cosmic-ray air-shower fluorescence at extreme energies require precise knowledge of atmospheric conditions. The absolute calibration of the cosmic-ray energy depends on the absorption of fluorescence light between its origin and point of its detection. To reconstruct basic atmospheric parameters we review a novel analysis method based on

R. Alkofer, P. Watson, H. Weigel

We develop a covariant approach to describe the low-lying scalar, pseudoscalar, vector and axialvector mesons as quark-antiquark bound states. This approach is based on an effective interaction modeling of the non--perturbative structure of the gluon propagator that enters the quark Schwinger-Dyson and meson Bethe-Salpeter equations. We consistently treat th

Luc Blanchet

The article reviews the current status of a theoretical approach to the problem of the emission of gravitational waves by isolated systems in the context of general relativity. Part A of the article deals with general post-Newtonian sources. The exterior field of the source is investigated by means of a combination of analytic post-Minkowskian and multipolar

B. Basu-Mallick, Tanaya Bhattacharyya

We find that the quantum monodromy matrix associated with a derivative nonlinear Schrodinger (DNLS) model exhibits U(2) or U(1,1) symmetry depending on the sign of the related coupling constant. By using a variant of quantum inverse scattering method which is directly applicable to field theoretical models, we derive all possible commutation relations among

J. D. Barrow, J. Magueijo, H. B. Sandvik

We study inhomogeneous cosmological variations in the fine structure 'constant', $α,$ in Friedmann universes. Inhomogeneous motions of the scalar field driving changes in $α$ display spatial oscillations that decrease in amplitude with increasing time. The inhomogeneous evolution quickly approaches that found for exact Friedmann universes. We prove a

Nobuhiro Maekawa, Toshifumi Yamashita

We propose a natural Higgs sector in E_6 grand unified theory (GUT) with anomalous U(1)_A gauge symmetry. In the scenario, the doublet-triplet splitting can be realized while the proton decay via dimension 5 operator is suppressed. The gauge coupling unification is also realized without finetuning. The GUT scale is generally lower than the usual GUT scale 2\

Vitor Cardoso, Jose' P. S. Lemos

We compute spectra, waveforms, angular distribution and total gravitational energy of the gravitiational radiation emitted during the radial infall of a massless particle into a Schwarzschild black hole. Our fully relativistic approach shows that (i) less than 50% of the total energy radiated to infinity is carried by quadrupole waves, (ii) the spectra is fl

P. Huber, T. Schwetz, J. W. F. Valle

Most neutrino mass theories contain non-standard interactions (NSI) of neutrinos which can be either non-universal (NU) or flavor-changing (FC). We study the impact of such interactions on the determination of neutrino mixing parameters at a neutrino factory using the so-called ``golden channels'' \pnu{e}\to\pnuμ for the measurement of θ_{13}. We sho

Marcelo Kuperman And Horacio Wio

We study a spatially homogeneous model of a market where several agents or companies compete for a wealth resource. In analogy with ecological systems the simplest case of such models shows a kind of "competitive exclusion" principle. However, the inclusion of terms corresponding for instance to "company efficiency" or to (ecological) "in

R. N. Rogalyov

The $N_c$-dependence of the vertices $PPPγ$, where $P$ is a pseudoscalar meson and $N_c$ is the number of colors, is analyzed with regard for the $N_c$-dependence of the quark charges. It is shown that the best processes for the determination of $N_c$ are the reactions $Kγ\to Kπ$ and $π^pmγ\toπ^\pmη$ as well as the decay $η\raπ^+π^-γ$. The measurement of the

Hitoshi Miyazaki, Izumi Tsutsui

Quantization of a harmonic oscillator with inverse square potential $V(x)=(m{ω^2}/2){x^2}+g/{x^2}$ on the line $-\infty<x<\infty$ is re-examined. It is shown that, for $0<g<3{\hbar^2}/(8m)$, the system admits a U(2) family of inequivalent quantizations allowing for quantum tunneling through the potenatial barrier at $x=0$. In the family is a distinguished qu

Xin-Nian Wang, Feng Yuan

The azimuthal asymmetry of $J/ψ$ suppression in non-central heavy-ion collisions is studied within a dynamic model of $J/ψ$ suppression in a deconfined partonic medium. Within this model, $J/ψ$ suppression in heavy-ion collisions is caused mainly by the initial state nuclear absorption and dissociation via gluon-$J/ψ$ scattering in deconfined partonic medium

Takeshi Fukuda, Kazuo Hosomichi

We study N=1 super Liouville theory on worldsheets with and without boundary. Some basic correlation functions on a sphere or a disc are obtained using the properties of degenerate representations of superconformal algebra. Boundary states are classified by using the modular transformation property of annulus partition functions, but there are some of those

J. J. Hudson, B. E. Sauer, M. R. Tarbutt, E. A. Hinds

The most sensitive measurements of the electron electric dipole moment d_e have previously been made using heavy atoms. Heavy polar molecules offer a greater sensitivity to d_e because the interaction energy to be measured is typically 10^3 times larger than in a heavy atom. We report the first measurement of this kind, for which we have used the molecule Yb

Itzhak Bars, Yutaka Matsuo

We give a detailed study of the associativity anomaly in open string field theory from the viewpoint of the split string and Moyal formalisms. The origin of the anomaly is reduced to the properties of the special infinite size matrices which relate the conventional open string to the split string variables, and is intimately related to midpoint issues. We di

Xiang-Mao Ding, Mark. D. Gould, Yao-Zhong Zhang

A new parafermionic algebra associated with the homogeneous space $A^{(2)}_2/U(1)$ and its corresponding $Z$-algebra have been recently proposed. In this paper, we give a free boson representation of the $A^{(2)}_2$ parafermion algebra in terms of seven free fields. Free field realizations of the parafermionic energy-momentum tensor and screening currents ar

Hyun Kyu Lee

Using a toy model of a two dimensional accretion disk, we discuss further the radial equation of the accretion flow dominated by the Poynting flux. Assuming the force-free condition is valid around the accretion disk, the relation between the fluid angular velocity of the disk, $Ω_D$, and the angular velocity of the magnetic field lines, $Ω_F$, is also discu

L. Lu, W. Yi, D. L. Zhang

We present a 3 omega method for simultaneously measuring the specific heat and thermal conductivity of a rod- or filament-like specimen using a way similar to a four-probe resistance measurement. The specimen in this method needs to be electrically conductive and with a temperature-dependent resistance, for acting both as a heater to create a temperature flu

A. K. Khitrin, V. L. Ermakov, B. M. Fung

Spin dynamics of a cluster of coupled spins 1/2 can be manipulated to store and process a large amount of information. A new type of dynamic response makes it possible to excite coherent long-living signals, which can be used for exchanging information with a mesoscopic quantum system. An experimental demonstration is given for a system of 19 proton spins of

W. Dür, J. I. Cirac

We study when a multipartite non--local unitary operation can deterministically or probabilistically simulate another one when local operations of a certain kind -in some cases including also classical communication- are allowed. In the case of probabilistic simulation and allowing for arbitrary local operations, we provide necessary and sufficient condition

Fabio Sattin

In this paper we present a simple model for computing single electron exchange between light nuclei. The electronic capture is pictured as a tunnelling process in a model potential. This allows to analytically compute the transmission probability. Some comparisons with data from existing literature are given.

A. F. Borghesani, M. Folegani, P. L. Frabetti, L. Piemontese

The excess electrons mobility $μ$ has been measured recently in liquid mixtures of Kr and CH$_{4}$ as a function of the electric field up to $E\approx 10^{4} V/cm $ and of the CH$_{4}$ concentration $x$ up to $x \approx 10 % ,$ at temperatures $T\approx 130 K,$ fairly close to the normal boiling point of Kr $(T_{b}\approx 120 K)$(folegani). We present here n

S. K. Feng, W. S. Graves, Y. N. Tang

The Source Development Lab (SDL) at BNL consists of a 230 MeV electron linac and a 10 m long wiggler for short wavelength Free Electronic Laser (FEL) development. The original control system [1] was based on the one in use at the National Synchrotron Light Source. In 2000 the control system was upgraded to be based on EPICS to facilitate software interfaces

Dipali Pal, Abhijit Sen, Munshi Golam Mustafa, Dinesh Kumar Srivastava

The evolution and production of strangeness from chemically equilibrating and transversely expanding quark gluon plasma which may be formed in the wake of relativistic heavy ion collisions is studied with initial conditions obtained from the Self Screened Parton Cascade (SSPC) model. The extent of partonic equilibration increases almost linearly with the squ

Helmut Oeschler

>A review of meson emission in heavy ion collisions at incident energies from SIS up to collider energies is presented. A statistical model assuming chemical equilibrium and local strangeness conservation (i.e. strangeness conservation per collision) explains most of the observed features. Emphasis is put onto the study of $K^+$ and $K^-$ emission at low inc

I. V. Barashenkov, V. S. Shchesnovich, R. Adams

We construct explicit multivortex solutions for the complex sine-Gordon equation (the Lund-Regge model) in two Euclidean dimensions. Unlike the previously found (coaxial) multivortices, the new solutions comprise $n$ single vortices placed at arbitrary positions (but confined within a finite part of the plane.) All multivortices, including the single vortex,

B. V. Chirikov, V. V. Vecheslavov

Preliminary results of extensive numerical experiments on a simple model specified by the smooth canonical strongly chaotic 2D-map with global virtual invariant curves (VICs) are presented and discussed. We focus on the statistics of the diffusion rate of individual trajectories in dependence on the model parameters. Our previous conjecture about the fractal

Lun-Shin Yao

All complex fluid motions, such as transition and turbulence, obeying the Navier-Stokes equations are non-linear phenomena. Some aspects of the non-linear terms of these equations are not well understood and are, in fact, misunderstood. The one-dimensional Kuramoto-Sivashinsky (KS) equation is used as a simple model non-linear partial differential equation t

Detlef Lehmann

We prove that the global minimum of the real part of the full effective potential of the many-electron system with attractive delta-interaction is in fact given by the BCS mean field configuration. This is a consequence of a simple bound which is obtained by applying Hadamard&#39;s inequality to the functional determinant. The second order Taylor expansion a

Vladislav V. Kravchenko

We show that the Maxwell equations for arbitrary inhomogeneous media are equivalent to a single quaternionic equation which can be considered as a generalization of the Vekua equation for generalized analytic functions.

Vladislav V. Kravchenko

A simple relation between the Maxwell system and the Dirac equation based on their quaternionic reformulation is discussed. We establish a close connection between solutions of both systems as well as a relation between the wave parameters of the electromagnetic field and the energy of the Dirac particle.

Nancy C. Wrinkle

A transverse knot is a knot that is transverse to the planes of the standard contact structure on real 3-space. In this paper we prove the Markov Theorem for transverse braids, which states that two transverse closed braids that are isotopic as transverse knots are also isotopic as transverse braids. The methods of the proof are based on Birman and Menasco&#

Ricardo S. Leite, Carlos Tomei

Given a real, symmetric matrix S, we define the slice through S as being the connected component containing S of two orbits under conjugation: the first by the orthogonal group, and the second by the upper triangular group. We describe some classical constructions in eigenvalue computations and integrable systems which keep slices invariant -- their properti

P. Kurlberg

Assuming the Generalized Riemann Hypothesis, we prove the following: If b is an integer greater than one, then the multiplicative order of b modulo N is larger than N^(1-ε) for all N in a density one subset of the integers. If A is a hyperbolic unimodular matrix with integer coefficients, then the order of A modulo p is greater than p^(1-ε) for all p in a de

G. Labelle, C. Lamathe, P. Leroux

We present new functional equations for the species of plane and of planar (in the sense of Harary and Palmer, 1973) 2-trees and some associated pointed species. We then deduce the explicit molecular expansion of these species, i.e a classification of their structures according to their stabilizers. There result explicit formulas in terms of Catalan numbers

Jih-Hsin Cheng

We study the fillability (or embeddability) of $CR$ structures under the gauge-fixed Cartan flow. We prove that if the initial $CR$ structure is fillable with nowhere vanishing Tanaka-Webster curvature and free torsion, then it keeps having the same property after a short time. In the Appendix, we show the uniqueness of the solution to the gauge-fixed Cartan

E. Carlini

The problem of simultaneous decomposition of binary forms as sums of powers of linear forms is studied. For generic forms the minimal number of linear forms needed is found and the space parametrizing all the possible decompositions is described. These results are applied to the study of rational curves.

Olaf Müller

Aim of this note is to extract cohomological information about the manifold $Emb(M,N)$ from the topology of the target manifold N. For special conditions, a monomorphism $H^1 (N) \to H^1 (Emb(M,N))$ is constructed.

Anatoly Libgober, Mihai Tibar

We obtain sufficient conditions for the vanishing of higher homotopy groups of the complements to hypersurfaces in ${\mathbb C}^n$ in terms of the behavior at infinity and relate the monodromy of non isolated singularities to the position of singularities in generic plane sections.

S. R. Gal, T. Januszkiewicz

The Baumslag-Solitar groups and their certain variations are a-T-menable. This is proved by embeding them into topological groups and studying representation theoretic properties of the latter. The paper is motivated by the questions of A. Valette.

Astrid an Huef, Iain Raeburn, Dana P. Willimas

We initiate a careful study of a generalized symmetric imprimitivity theory for commuting proper actions of locally compact groups H and K on a C*-algebra.

Anthony Henderson

We prove that the local intersection cohomology of nilpotent orbit closures of cyclic quivers is trivial when the two orbits involved correspond to partitions with at most two rows. This gives a geometric proof of a result of Graham and Lehrer, which states that standard modules of the affine Hecke algebra of $GL_d$ corresponding to nilpotents with at most t

Emmanuel Maitre

We consider a nonlinear counterpart of a compactness lemma of J. Simon, which arises naturally in the study of doubly nonlinear equations of elliptic-parabolic type. Our work was motivated by previous results J. Simon, recently sharpened by H. Amann, in the linear setting, and by a nonlinear compactness argument of H.W. Alt and S. Luckhaus.

G. Sardanashvily

Non-Fock representations of the canonical commutation relations modeled over an infinite-dimensional nuclear space are constructed in an explicit form. The example of the nuclear space of smooth real functions of rapid decrease results in nonequivalent quantizations of scalar fields.

E. Kiritsis, N. Tetradis, T. N. Tomaras

It is shown that a localized four-dimensional Einstein term, induced by quantum corrections, modifies significantly the law of gravity in a Randall-Sundrum brane world. In particular, the short-distance behavior of gravity changes from five- to four-dimensional, while, depending on the values of parameters, there can be an intermediate range where gravity be

Ion I. Cotăescu, Mihai Visinescu

It is shown that the N=4 superalgebra of the Dirac theory in Taub-NUT space has different unitary representations related among themselves through unitary U(2) transformations. In particular the SU(2) transformations are generated by the spin-like operators constructed with the help of the same covariantly constant Killing-Yano tensors which generate Dirac-t

M. Beneke

A brief report on the QCD factorization approach to exclusive B decays and its applications is presented. In an appendix a subtle issue concerning partial integration in the parameterization of infrared-sensitive power corrections is clarified.

I. F. Ginzburg, S. I. Polityko

In this report our main attention is focused on the problems which can be solved at Photon Colliders naturally but are hardly solved at LHC and e^+e^- Linear Collider: The New Physics - new particles, new interactions, supersymmetry, Dirac monopole, extra dimensions... SM and the case of a SM--like scenario - EWSB, Higgs bosons, anomalies in interactions of

K. Kang, V. V. Ezhela, S. K. Kang, S. B. Lugovsky

In the light of recent muon (g-2) result by the E821 experiment at BNL, the importance of and interest in the total hadronic cross sections in e+ e- collisions and R(e+ e- --> hadrons) have been heightened. We report on the integrated data compilation of available data of e+ e- --> hadrons, transformed to a unique and meaningful style that implements the pur

Wei Min Yang, Dong Sheng Du

We investigate CP violation asymmetry in the decay of tau slepton into a tau neutrino and a chargino in the minimal supersymmetric standard model. The new source of CP violation is the complex mixing in the tau slepton sector. The rate asymmetry between the decays of tau slepton and its CP conjugate process can be of order of $10^{-3}$ in some region of the

N. N. Achasov, A. V. Kiselev

Using new experimental data, we have calculated the contribution to the anomalous magnetic moment of the muon from the \pi0γand ηγintermediate states in the vacuum polarization with high precision: aμ(\pi0γ)+aμ(ηγ)=(54.7\pm 1.5)\times 10^{-11}. We have also found the small contribution from e+e-\pi0, e+e-ηand μ+μ-\pi0 intermediate states equal to 0.5\times 1

Saurabh D. Rindani

CP-violating asymmetries in the processes e+e- -> t tbar and gamma gamma -> ttbar can provide information about CP-violating couplings of the top quark, whose presence would signal physics beyond the standard model. Work on studies of different asymmetries has been described. Special emphasis has been laid on asymmetries in charged lepton distributions arisi

A. G. Akeroyd, S. Recksiegel

We study the direct CP asymmetry of the decays b -> s gamma and b -> d gamma in the context of two models: i) a supersymmetric (SUSY) model with unconstrained SUSY phases, and ii) a model with a single generation of vector quarks. In both the above models we show that b -> d gamma can sizeably influence the combined asymmetry (i.e. that of a sample containin

I. I. Bigi

It has been suggested that the observed $D_s - D^0$ lifetime difference can be `understood&#39; as due to $SU(3)_{Fl}$ breaking in the phase spaces for the exclusive $D^0$ and $D_s$ channels `removing&#39; the need for weak annihilation. It is pointed out that several of the statements in this argument are misleading or even inconsistent with a state-of-the-

The KTeV Collaboration, A. Alavi-Harati

We present a measurement of the charge asymmetry $δ_L$ in the mode $K_L \to π^{\pm}e^{\mp}ν$ based on 298 million analyzed decays. We measure a value of $δ_L = (3322 \pm 58(stat) \pm 47(sys))\cdot 10^{-6}$, in good agreement with previous measurements and 2.4 times more precise than the current best published result. The result is used to place more stringen

F. Loup, R. Held, D. Waite, E. Halerewicz,

It will be shown that while horizons do not exist for warp drive spacetimes traveling at subluminal velocities horizons begin to develop when a warp drive spacetime reaches luminal velocities. However it will be shown that the control region of a warp drive ship lie within the portion of the warped region that is still causally connected to the ship even at

M. A. Abramowicz, G. J. E. Almergren, W. Klu{ź}niak, A. V. Thampan

Quantized orbital structures are typical for many aspects of classical gravity (Newton&#39;s as well as Einstein&#39;s). The astronomical phenomenon of orbital resonances is a well-known example. Recently, Rothman, Ellis and Murugan (2001) discussed quantized orbital structures in the novel context of a holonomy invariance of parallel transport in Schwarzsch

Gaetano Vilasi, Patrizia Vitale

The role of the SO(2,1) symmetry in General Relativity is analyzed. Cosmological solutions of Einstein field equations invariant with respect to a space-like Lie algebra G_r, with r between 3 and 6 and containing so(2,1) as a subalgebra, are also classified.

Kenji Sakamoto, Kiyoshi Shiraishi

In this work, we discuss the quantum mechanics on the moduli space consisting of two maximally charged dilaton black holes. We study the quantum effects resulting from the different structure of the moduli space geometry in the scattering process.

Petros Maniatis, Mary Baker

A secure timeline is a tamper-evident historic record of the states through which a system goes throughout its operational history. Secure timelines can help us reason about the temporal ordering of system states in a provable manner. We extend secure timelines to encompass multiple, mutually distrustful services, using timeline entanglement. Timeline entang

A. V. Nikulov, S. V. Dubonos, Y. I. Koval

It was shown as long ago as 1998 cond-mat/9811051 that the vortex lattice melting theories are science fiction because the Abrikosov state is not the vortex lattice with crystalline long-range order. Nevertheless this false conception is used up to now in many works including the lecture notes cond-mat/0111052 providing a pedagogical introduction. This false

Cristina Bena, Smitha Vishveshwara, Leon Balents, Matthew P. A. Fisher

With the surge of research in quantum information, the issue of producing entangled states has gained prominence. Here, we show that judiciously bringing together two systems of strongly interacting electrons with vastly differing ground states - the gapped BCS superconductor and the Luttinger liquid, - can result in quantum entanglement. We propose three se

K. Held, E. Eisenberg, B. L. Altshuler

Within random matrix theory for quantum dots, both the dot&#39;s one-particle eigenlevels and the dot-lead couplings are statistically distributed. While the effect of the latter on the conductance is obvious and has been taken into account in the literature, the statistical distribution of the one-particle eigenlevels is generally replaced by a picket-fence

M. S. Mainieri, R. Erichsen

We discuss, in this paper, the dynamical properties of extremely diluted, non-monotonic neural networks. Assuming parallel updating and the Hebb prescription for the synaptic connections, a flow equation for the macroscopic overlap is derived. A rich dynamical phase diagram was obtained, showing a stable retrieval phase, as well as a cycle two and chaotic be

Hae-Young Kee, Yong Baek Kim

The renormalization factor, dubbed ``quasiparticle charge&#39;&#39; Z_e, of the coupling between the supercurrent and quasiparticles was analyzed in the context of high temperature cuprates in a recent paper by Ioffe and Millis. They observed that Z_e in cuprates deviates from the BCS value (Z_e=1), which was interpreted as the proximity effect near a Mott i

Masako Yamada, Stefano Mossa, H. Eugene Stanley, Francesco Sciortino

We study the TIP5P water model proposed by Mahoney and Jorgensen, which is closer to real water than previously-proposed classical pairwise additive potentials. We simulate the model in a wide range of deeply supercooled states and find (i) the existence of a non-monotonic ``nose-shaped&#39;&#39; temperature of maximum density line and a non-reentrant spinod

Chi-Yong Lin, E. J. V. de Passos, M. S. Hussein, Da-Shin Lee

The equilibrium and stability properties of a coupled two-component BEC is studied using a variational method and the one-dimensional model of Williams and collaborators. The variational parameters are the population fraction, translation and scaling transformation of the condensate densities, assumed to have a Gaussian shape. We study the equilibrium and st

O. Chubykalo, R. Smirnov-Rueda, M. A. Wongsam, R. W. Chantrell

The question how to introduce thermal fluctuations in the equation of motion of a magnetic system is addressed. Using the approach of the fluctuation-dissipation theorem we calculate the properties of the noise for both, the fluctuating field and fluctuating torque (force) representation. In contrast to earlier calculations we consider the general case of a

Federico Corberi, Eugenio Lippiello, Marco Zannetti

The basic features of the slow relaxation phenomenology arising in phase ordering processes are obtained analytically in the large $N$ model through the exact separation of the order parameter into the sum of thermal and condensation components. The aging contribution in the response function $χ_{ag}(t,t_w)$ is found to obey a pattern of behavior, under vari

Cristian Micheletti

A variety of experimental and theoretical studies have established that the folding process of monomeric proteins is strongly influenced by the topology of the native state. In particular, folding times have been shown to correlate well with the contact order, a measure of contact locality. Our investigation focuses on identifying additional topologic proper

I. Terasaki, I. Tsukada, Y. Iguchi

Various physical quantities are measured and analysed for the Cu-substituted thermoelectric oxide NaCo_{2-x}Cu_xO_4. As was previously known, the substituted Cu enhances the thermoelectric power, while it does not increase the resistivity significantly. The susceptibility and the electron specific-heat are substantially decreased with increasing x, which imp

W. Koayashi, A. Satake, I. Terasaki

We prepared the brownmillerite oxide Ca_{2-y}La_yCo_{2-x}Al_xO_5, and found that it was an n-type conductor. The thermopower and the resistivity of the single crystal are -90 microV/K and 68 mOhm cm along the ab direction at 440 K, which suggest relatively good thermoelectrical properties, compared with other transition-metal oxides. Their temperature depend

Patrizia Vignolo, Anna Minguzzi

We consider a system of one-dimensional non-interacting fermions in external harmonic confinement. Using an efficient Green&#39;s function method we evaluate the exact profiles and the pair correlation function, showing a direct signature of the Fermi statistics and of the single quantum-level occupancy. We also study the dynamical properties of the gas, obt

U. Al Khawaja, J. O. Andersen, N. P. Proukakis, H. T. C Stoof

We present an improved many-body T-matrix theory for partially Bose-Einstein condensed atomic gases by treating the phase fluctuations exactly. The resulting mean-field theory is valid in arbitrary dimensions and able to describe the low-temperature crossover between three, two and one-dimensional Bose gases. When applied to a degenerate two-dimensional atom

A. Perali, P. Pieri, G. C. Strinati, C. Castellani

The crossover from weak to strong coupling for a three dimensional continuum model of fermions interacting via an attractive contact potential is studied above the superconducting critical temperature. The pair-fluctuation propagator, the one-loop self-energy, and the spectral function are investigated in a systematic way from the superconducting fluctuation

D. V. Averin

The concept of quantum nondemolition (QND) measurement is extended to coherent oscillations in an individual two-state system. Such a measurement enables direct observation of intrinsic spectrum of these oscillations avoiding the detector-induced dephasing that affects the standard (non-QND) measurements. The suggested scheme can be realized in Josephson-jun

Yu. G. Gurevich, G. N. Logvinov, O. Yu. Titov, J. Giraldo

We suggest a new approach to the theory of the contact thermoelectric cooling (Peltier effect). The metal-metal, metal-n-type semiconductor, metal-p-type semiconductor, p-n junction contacts are analyzed. Both degenerate and non-degenerate electron and hole gases are considered. The role of recombination in the contact cooling effect is discussed by the firs

Akira Kawaguchi, Akihisa Koga, Kouichi Okunishi, Norio Kawakami

We investigate the magnetization process for a quasi-one-dimensional S=1 antiferromagnet with bond alternation. By combining the density matrix renormalization group method with the interchain mean-field theory, we discuss how the interchain coupling affects the magnetization curve. It is found that the width of the magnetization plateau is considerably redu

Z. Y. Weng, V. N. Muthukumar

In the description of spin-charge separation based on the phase string theory of the t-J model, spinon excitations are vortices in the superconducting state. Thermally excited spinons destroy phase coherence, leading to a new phase characterized by the presence of free spinon vortices at temperatures, T_c<T<T_v. The temperature scale T_v at which holon conde

I. R. Shein, S. V. Okatov, N. I. Medvedeva, A. L. Ivanovskii

Electronic band structure of boron-rich low-temperature superconductors UB12-like dodecaboride YB12 and CaB6-like hexaboride YB6 are investigated using the first-principle FLMTO calculations and compared with one for layered YB2 and the new &#34;medium-Tc&#34; superconductor MgB2 diborides.

Falk Herwig

We present a stellar evolution model sequence of the past and future evolution of the post-AGB born again star Sakurai&#39;s object (V4334 Sgr). In order to match the short evolutionary time scale we have to assume that the convective ingestion of hydrogen-rich envelope material into the He-flash convection zone proceeds slower than predicted by the mixing l

W. F. Tompkins

The field of gamma ray astronomy relies heavily on the statistical analysis of data. Because of the paucity of data, and the often large errors associated with detecting gamma rays, analysis and interpretation of the data require sophisticated statistical techniques. Techniques for extending the currently used maximum likelihood technique to more complicated

Jason X. Prochaska, J. Christopher Howk, John M. O&#39;Meara, David Tytler

We investigate the ionization state of the damped Lya system at z=2.62 toward GB1759+7539 through an analysis of ionic ratios sensitive to photoionization: ArI/SII, FeIII/FeII, NII/NI, AlIII/AlII. Approximately half of the metals arise in a mostly neutral velocity component with HI/H > 0.9, based on FeIII/FeII < 0.013. In contrast, the remaining half exhibit

Geoffrey C. Bower, Heino Falcke, Robert J. Sault, Donald C. Backer

We report here multi-epoch, multi-frequency observations of the circular polarization in Sagittarius A*, the compact radio source in the Galactic Center. Data taken from the VLA archive indicate that the fractional circular polarization at 4.8 GHz was -0.31% with an rms scatter of 0.13% from 1981 to 1998, in spite of a factor of 2 change in the total intensi

James P. Lloyd, Ben R. Oppenheimer, James R. Graham

The low infrared background and high atmospheric transparency are the principal advantages of Antarctic Plateau sites for astronomy. However, the poor seeing (between one and three arcseconds) negates much of the sensitivity improvements that the Antarctic atmosphere offers, compared to mid-latitude sites such as Mauna Kea or Cerro Paranal. The seeing at mid

O. Doré, S. Colombi, F. R. Bouchet

It is possible to classify pixels of a smoothed cosmic microwave background (CMB) fluctuation map according to their local curvature in ``hill&#39;&#39;, ``lake&#39;&#39; and ``saddle&#39;&#39; regions. In the Gaussian case, fractional areas occupied by pixels of each kind can be computed analytically for families of excursion sets as functions of threshold

C. Ledoux, J. Bergeron, P. Petitjean

We analyse a sample of 24 damped Lyman-alpha (DLA)/moderate DLA systems at 0.3<z<2.2, all with measurement of the weak MnII absorption lines, to investigate which elemental ratios could possibly be used as tracers of either dust depletion or nucleosynthesis effects. We applied a component-by-component analysis and show that the standard method which uses col

G. Kovács

We briefly describe a method of obtaining relative intrinsic stellar parameters, such as absolute magnitudes and colors from the light curves of fundamental mode RR Lyrae (RRab) stars. Absolute stellar parameters of double-mode variables (Cepheids and RR Lyrae stars) can be computed from their periods and intrinsic colors combined with stellar atmosphere and

Nicholas Cross, Simon Driver, David Lemon, Jochen Liske

We present Bivariate Brightness Distributions (BBDs) for four spectral types discriminated by the 2dFGRS. We discuss the photometry and completeness of the 2dFGRS using a deep, wide-field CCD imaging survey. We find that there is a strong luminosity-surface brightness correlation amongst galaxies with medium to strong emission features, with gradient $β_μ=0.

Roberto Barmina, Leo Girardi, Cesare Chiosi

The young LMC cluster NGC 1866 represents the ideal laboratory for testing stellar evolutionary models: in particular, it can be used to discriminate among classical stellar models, in which the extension of the convective regions is fixed by the classical Schwarzschild criterion, from models with overshooting, in which an ``extra-mixing&#39;&#39; is conside

Ninan Sajeeth Philip, Yogesh Wadadekar, Ajit Kembhavi, K. Babu Joseph

In this paper we describe the use of a new artificial neural network, called the difference boosting neural network (DBNN), for automated classification problems in astronomical data analysis. We illustrate the capabilities of the network by applying it to star galaxy classification using recently released, deep imaging data. We have compared our results wit

F. V. Prigara

Using the principle of detailed balance and the assumption on the absorption cross-section consistent with available astrophysical data, we obtain the energy distribution of atoms in the field of thermal blackbody radiation and show that this distribution diverges from the Boltzmann law.

G. Kovács

Recent analyses of photometric data on globular clusters and galaxies enabled us to study more closely the long-periodic amplitude/phase modulation (Blazhko effect) in classical variables. In the frequency spectra of these stars we see either a doublet or an equally-spaced triplet with a very small frequency separation close to the main component. None of th