August 2004 arXiv papers — page 5

Andrew Das Arulsamy

The 2D models of heat capacity, its conductivity ($κ$), Hall resistance ($R_H$) and the Lorenz ratio ($\mathcal{L}$) have been derived using the ionization energy ($E_I$) based Fermi-Dirac statistics (iFDS). These models reproduce the experimentally measured $ρ(T)$ and $R_H(T)$. The variation of $\mathcal{L}$ is proportional to 1/T due to electron-phonon ($e

G. J. Mathews, T. Kajino, T. Shima

We show that the predicted primordial helium production is significantly reduced when new measurements of the neutron lifetime and the implied enhancement in the weak reaction rates are included in big-bang nucleosynthesis. Therefore, even if a narrow uncertainty in the observed helium abundance is adopted, this brings the constraint on the baryon-to-photon

M. Hennion, F. Moussa, P. Lehouelleur, F. Wang

We report a study of spin-waves in ferromagnetic La$_{1-x}$Ca$_{x}$MnO$_3$, at concentrations x=0.17 and x=0.2 very close to the metallic transition (x=0.225). Below T$_C$, in the quasi-metallic state (T=150K), nearly q-independent energy levels are observed. They are characteristic of standing spin waves confined into finite-size ferromagnetic domains, defi

Eric Sultan, Arezki Boudaoud, Martine Ben Amar

The stability of an evaporating thin liquid film on a solid substrate is investigated within lubrication theory. The heat flux due to evaporation induces thermal gradients; the generated Marangoni stresses are accounted for. Assuming the gas phase at rest, the dynamics of the vapour reduces to diffusion. The boundary condition at the interface couples transf

Wung-Hong Huang

We use the Dirac-Born-Infeld action on Dp-brane background to find the tubular bound state of a D2 with $m$ D0-branes and $n$ fundamental strings. The fundamental strings may be the circular strings along the cross section of tube or the straight strings along the axial of the tube, and tube solutions are parallel to the geometry of Dp-brane background. Thro

T. Matsuzaki, N. Momono, M. Oda, M. Ido

To examine the so-called small pseudogap and the superconducting (SC) condensation energy U(0), the electronic specific heat Cel was measured on La_{2-x}Sr_{x}CuO_{4} up to ~120K. In samples with doping level p (=x) less than ~0.2, small pseudogap behavior appears in the γ(=Cel/T) vs. T curve around the mean-field critical temperature for a d-wave supercondu

M. Kubouchi, K. Yoshioka, R. Shimano, A. Mysyrowicz

Using time-resolved $1s$-$2p$ excitonic Lyman spectroscopy, we study the orthoexciton-to-paraexcitons transfer, following the creation of a high density population of ultracold $1s$ orthoexcitons by resonant two-photon excitation with femtosecond pulses. An observed fast exciton-density dependent conversion rate is attributed to spin exchange between pairs o

Robin de Jong

Using an explicit version of the Mumford isomorphism on the moduli space of hyperelliptic curves we derive a closed formula for the Arakelov-Green function of a hyperelliptic Riemann surface evaluated at its Weierstrass points.

V. Ravindran, J. Smith, W. L. van Neerven

In this paper we present the complete two-loop vertex corrections to scalar and pseudo-scalar Higgs boson production for general colour factors for the gauge group ${\rm SU(N)}$ in the limit where the top quark mass gets infinite. We derive a general formula for the vertex correction which holds for conserved and non conserved operators. For the conserved op

Carsten Timm, M. E. Raikh, Felix von Oppen

We show that the resistivity rho(T) of disordered ferromagnets near, and above, the Curie temperature T_c generically exhibits a stronger anomaly than the scaling-based Fisher-Langer prediction. Treating transport beyond the Boltzmann description, we find that within mean-field theory, dρ/dT exhibits a |T-T_c|^{-1/2} singularity near T_c. Our results, being

W. -X. Zhou, D. Sornette

Fractals and multifractals and their associated scaling laws provide a quantification of the complexity of a variety of scale invariant complex systems. Here, we focus on lattice multifractals which exhibit complex exponents associated with observable log-periodicity. We perform detailed numerical analyses of lattice multifractals and explain the origin of t

Paul Romatschke, Michael Strickland

In 1959 Weibel demonstrated that when a QED plasma has a temperature anisotropy there exist unstable transverse magnetic excitations which grow exponentially fast. In this paper we will review how to determine the growth rates for these unstable modes in the weak-coupling and ultrarelativistic limits in which the collective behavior is describable in terms a

K. Nagata, A. Hosaka, L. J. Abu-Raddad

The mass of the nucleon is studied in a chiral quark-diquark model. Both scalar and axial-vector diquarks are taken into account for the construction of the nucleon state. After the hadronization procedure to obtain an effective meson-baryon Lagrangian, the quark-diquark self-energy is calculated in order to generate the baryon kinetic term as well as the ma

Akihiro Haga, Setsuo Tamenaga, Hiroshi Toki, Yataro Horikawa

We study the relativistic Hartree approach with the exact treatment of the vacuum polarization in the Walecka sigma-omega model. The contribution from the vacuum polarization of nucleon-antinucleon field to the source term of the meson fields is evaluated by performing the energy integrals of the Dirac Green function along the imaginary axis. With the presen

Andreas Luscher, Oleg P. Sushkov

We consider a two-dimensional Heisenberg antiferromagnet on a square lattice with weakly coupled impurities, i.e. additional spins interacting with the host magnet by a small dimensionless coupling constant g<<1. Using linear spin-wave theory, we find that the magnetization disturbance at distance r from a single impurity behaves as g/r for 1<<r<<1/g and as

K. Glantschnig, R. Kainhofer, W. Plessas, B. Sengl

We present an extension of the Goldstone-boson-exchange constituent quark model including additional interactions beyond the ones used hitherto. For the hyperfine interaction between the constituent quarks we assume pseudoscalar, vector, and scalar meson exchanges and consider all relevant force components produced by these types of exchanges. The resulting

K. Andrzejewski, P. Maslanka

Algebraic derivation of modified Heisenberg commutation rules for restricted Landau problem is given.

L. Pollet, S. M. A. Rombouts, P. J. H. Denteneer

Recent experiments on ultracold atomic alkali gases in a one-dimensional optical lattice have demonstrated the transition from a gas of soft-core bosons to a Tonks-Girardeau gas in the hard-core limit, where one-dimensional bosons behave like fermions in many respects. We have studied the underlying many-body physics through numerical simulations which accom

Victor S. L&#39;vov, Sergey V. Nazarenko, Grigory E. Volovik

The spectrum of turbulence in superfluid liquid is modified by the nonlinear energy dissipation caused by the mutual friction between quantized vortices and the normal component of the liquid. In some region of two Reynolds parameters characterizing the flow of a superfluid, we found the new state of the fully developed turbulence. This state displays both t

Siddhartha Gadgil

We construct an invariant of open four-manifolds using the Heegaard Floer theory of Ozsvath and Szabo. We show that there is a manifold X homeomorphic to R^4 for which the invariant is non-trivial, showing that X is an exotic R^4.

Andrzej Jamiołkowski

In this paper, we discuss the minimal number of observables, where expectation values at some time instant determine the trajectory of a d-level quantum system (&#34;qudit&#34;) governed by the Gaussian semigroup. We assume that the macroscopic information about the system in question is given by the mean values of n selfadjoint operators $Q_1,...,Q_n$ at so

Markus Meissner, Christoph Marquardt, Joel Heersink, Tobias Gaber

An all-fibre source of amplitude squeezed solitons utilizing the self-phase modulation in an asymmetric Sagnac interferometer is experimentally demonstrated. The asymmetry of the interferometer is passively controlled by an integrated fibre coupler, allowing for the optimisation of the noise reduction. We have carefully studied the dependence of the amplitud

Sudhir R. Jain

We discover that the energy-integral of time-delay is an adiabatic invariant in quantum scattering theory and corresponds classically to the phase space volume. The integral thus found provides a quantization condition for resonances, explaining a series of results recently found in non-relativistic and relativistic regimes. Further, a connection between sta

You-Quan Li, Yong-Yun Ji, Jun-Wen Mao, Xiao-Wei Tang

We study the medium effects on the selection of sequences in protein folding by taking account of the surface potential in HP-model. Our analysis on the proportion of H and P monomers in the sequences gives a direct interpretation that the lowly designable structures possess small average gap. The numerical calculation by means of our model exhibits that the

Irina Novikova, Alexander Khanbekyan, David Sarkisyan, George R. Welch

We report the first measurements of linear and nonlinear magneto-optical polarization rotation on an intercombination transition of Ba vapor (lambda= 791.1nm). We observe a maximum polarization rotation angle in Faraday configuration of 15mrad, accompanied by suppression of absorption. A theoretical treatment of the nonlinear Faraday effect in the limit of a

Edward W. Piotrowski, Jan Sladkowski

We discuss some aspects of Astumian suggestions that combination of biased games (Parrondo&#39;s paradox) can explain performance of molecular motors. Unfortunately the model is flawed by explicit asymmetry overlooked by the author. In addition, we show that taking into consideration stakes allows to remove the paradoxical behaviour of Parrondo games.

Yuri Yu. Tarasevich

An analytical expression of velocity potential inside an evaporating sessile drop with pinned contact line is found.

J. Mitroy, M. W. J. Bromley

The static and dynamic properties of the alkaline-earth atoms in their metastable state are computed in a configuration interaction approach with a semi-empirical model potential for the core. Among the properties determined are the scalar and tensor polarizabilities, the quadrupole moment, some of the oscillator strengths and the dispersion coefficients of

Takahiro Mizusaki

An extrapolation method in shell model calculations with deformed basis is presented, which uses a scaling property of energy and energy variance for a series of systematically approximated wave functions to the true one. Such approximated wave functions are given by variation-after-projection method concerning the full angular momentum projection. This extr

H. Mueller, V. I. Komarov

Data from KEK on subthreshold antiproton as well as on charged pion and kaon production in pC, dC and $α$C reactions at energies between 3.5 and 12.0 A GeV are described for the first time within a unified approach. We use a model which considers a nuclear reaction as an incoherent sum over collisions of varying numbers of projectile and target nucleons. It

David P. Chassin, Joel Malard, Christian Posse

Physical analogs have shown considerable promise for understanding the behavior of complex adaptive systems, including macroeconomics, biological systems, social networks, and electric power markets. Many of today&#39;s most challenging technical and policy questions can be reduced to a distributed economic control problem. Indeed, economically-based control

Dranreb Earl Juanico, Christopher Monterola, Caesar Saloma

Animal and human clusters are complex adaptive systems and many are organized in cluster sizes $s$ that obey the frequency-distribution $D(s)\propto s^{-τ}$. Exponent $τ$ describes the relative abundance of the cluster sizes in a given system. Data analyses have revealed that real-world clusters exhibit a broad spectrum of $τ$-values, $0.7\textrm{(tuna fish

O. B. Isaeva, S. P. Kuznetsov, A. H. Osbaldestin

As shown recently (O.B.Isaeva et al., Phys.Rev E64, 055201), the phenomena intrinsic to dynamics of complex analytic maps under appropriate conditions may occur in physical systems. We study scaling regularities associated with the effect of additive noise upon the period-tripling bifurcation cascade generalizing the renormalization group approach of Crutchf

J. Duan, H. Gao, B. Schmalfuss

The investigation of the coupled atmosphere-ocean system is not only scientifically challenging but also practically important. We consider a coupled atmosphere-ocean model, which involves hydrodynamics, thermodynamics, and random atmospheric dynamics due to short time influences at the air-sea interface. We reformulate this model as a random dynamical syste

Hongjun Gao, Jinqiao Duan

We consider a coupled atmosphere-ocean model, which involves hydrodynamics, thermodynamics and nonautonomous interaction at the air-sea interface. First, we show that the coupled atmosphere-ocean system is stable under the external fluctuation in the atmospheric energy balance relation. Then, we estimate the atmospheric temperature feedback in terms of the f

Daniel Maisner, Enric Nart

We determine what isogeny classes of supersingular abelian surfaces over a finite field k of characteristic 2 contain jacobians. We deal with this problem in a direct way by computing explicitly the zeta function of all supersingular curves of genus 2. Our procedure is constructive, so that we are able to exhibit curves with prescribed zeta function and to c

Jan-Hendrik Evertse, Roberto G. Ferretti

Recently, Corvaja and Zannier obtained an extension of the Subspace Theorem with arbitrary homogeneous polynomials of arbitrary degreee instead of linear forms. Their result states that the set of solutions in P^n(K) (K number field) of the inequality being considered is not Zariski dense. In our paper we prove by a different method a generalization of their

U. K. Anandavardhanan, C. S. Rajan

We show the equality of the local Asai L-functions defined via the Rankin-Selberg method and the Langlands-Shahidi method for a square integrable representation of GL(n,E). As a consequence we characterise reducibility of certain induced representations of U(n,n), and the image of the base change map from U(n) to GL(n,E) in terms of GL(n,F)-distinguishedness

S. A. Belbas

We obtain the dynamic programming equations and optimality conditions akin to Pontryagin&#39;s extremum principle for certain mathematical models of hybrid control systems.

Guoce Xin

This paper deals with evaluating constant terms of a special class of rational functions, the Elliott-rational functions. The constant term of such a function can be read off immediately from its partial fraction decomposition. We combine the theory of iterated Laurent series and a new algorithm for partial fraction decompositions to obtain a fast algorithm

Andrew Bremner, Nikos Tzanakis

Let P and Q be non-zero integers. The Lucas sequence U_n(P,Q), n=0,1,2,... is defined by U_0=0, U_1=1, U_n= P U_{n-1}-Q U_{n-2} for n>1. For each positive integer n<8 we describe all Lucas sequences with (P,Q)=1 having the property that U_n(P,Q) is a perfect square. The arguments are elementary. The main part of the paper is devoted to finding all Lucas sequ

Ilya Kapovich

We analyze the structure of the \emph{frequency space} $Q(F)$ of a nonabelian free group $F=F(a_1,...,a_k)$ consisting of all shift-invariant Borel probability measures on $\partial F$ and construct a natural action of $Out(F)$ on $Q(F)$. In particular we prove that for any outer automorphism $ϕ$ of $F$ the \emph{conjugacy distortion spectrum} of $ϕ$, consis

Ilya Kapovich, Paul Schupp, Vladimir Shpilrain

We prove that Whitehead&#39;s algorithm for solving the automorphism problem in a fixed free group $F_k$ has strongly linear time generic-case complexity. This is done by showing that the ``hard&#39;&#39; part of the algorithm terminates in linear time on an exponentially generic set of input pairs. We then apply these results to one-relator groups. We obtai

Ilya Kapovich, Richard Weidmann

We prove an acylindrical accessibility theorem for finitely generated groups acting on $\mathbf R$-trees. Namely, we show that if $G$ is a freely indecomposable non-cyclic $k$-generated group acting minimally and $M$-acylindrically on an $\mathbf R$-tree $X$ then for any $ε>0$ there is a finite subtree $Y_ε\subseteq X$ of measure at most $2M(k-1)+ε$ such tha

A. Feo, P. Merlatti, F. Sannino

We investigate the spectrum of the lightest states of N=1 Super Yang-Mills. We first study the spectrum using the recently extended Veneziano Yankielowicz theory containing also the glueball states besides the gluinoball ones. Using a simple Kahler term we show that within the effective Lagrangian approach one can accommodate either the possibility in which

M. O. Tahim, C. A. S. Almeida

In this work we explore an alternative to the central point of the Randall-Sundrum brane world scenario, namely, the particular nonfactorizable metric, in order to solve the hierarchy problem. From a topological viewpoint, we show that the exponential factor, crucial in the Randall-Sundrum model, appears in our approach, only due to the brane existence inste

G. Y. Shahin, M. S. Shikakhwa

In the framework of QED, scalar pair production by a single linearly polarized high-energy photon in the presence of an external Aharonov-Bohm potential is investigated. The exact scattering solutions of the Klein-Gordon equation in cylindrically symmetric field are constructed and used to write the first order transition amplitude. The matrix elements and t

Makoto Sakaguchi, Kentaroh Yoshida

We briefly review a covariant analysis of D-branes of type IIB superstring on the AdS_5xS^5 background from the κ-invariance of the Green-Schwarz string action. The possible configurations of D-branes preserving half of supersymmetries are classified in both cases of AdS_5xS^5 and the pp-wave background.

I. Carrillo-Ibarra, H. Garcia-Compean, W. Herrera-Suarez

Gauged WZW and coset models are known to be useful to prove holomorphic factorization of the partition function of WZW and coset models. In this note we show that these gauged models can be also important to quantize the theory in the context of the Berezin formalism. For gauged coset models Berezin quantization procedure also admits a further holomorphic fa

C Meusburger, B J Schroers

We quantise a Poisson structure on H^{n+2g}, where H is a semidirect product group of the form $G\ltimes\mathfrak{g}^*$. This Poisson structure arises in the combinatorial description of the phase space of Chern-Simons theory with gauge group $G\ltimes\mathfrak{g}^*$ on $R \times S_{g,n}$, where S_{g,n} is a surface of genus g with n punctures. The quantisat

Stefano Frixione

I briefly review the theory and phenomenology of bottom production at colliders. When all theoretical uncertainties are taken into proper account, and modern measurements are considered, no significant discrepancy is seen between data and QCD predictions

Stefano Frixione

Substantial progress has been made recently in the formalisms which form the basis of event generators. I discuss some of the ideas involved, emphasizing the role of higher-order QCD corrections and their interplay with parton showers

Michio Hashimoto, Shinya Kanemura

We discuss a mechanism to generate hierarchy between masses of the top and bottom quarks without fine-tuning of the Yukawa coupling constants. In the framework of the two-Higgs-doublet model (THDM) with a discrete $Z_2$ symmetry, there exists the vacuum where only the top quark receives the mass of the order of the electroweak symmetry breaking scale $v(\sim

Edmond Iancu

I discuss elastic dipole-dipole scattering in QCD at high energies, with emphasis on the relation between Mueller&#39;s dipole picture and the Color Glass Condensate, and on the importance of rare fluctuations for the high-energy limit of the S-matrix.

T. Morozumi, Z. Xiong, T. Yoshikawa

In the framework of SU(2) singlet down type vectorlike quark model, we present a comprehensive analysis for decays B-> X_s γ, B->X_sl^+l^- and B-> Kπ. As for B-> X_sγ, we include the QCD running from the mass of the down-type vector quark D to weak scale in the scenario with the D quark much heavier than weak scale, and find that the running effect is small.

A. I. Alekseev, B. A. Arbuzov

Under assumption of singular behavior of alpha_s(q^2) at q^2 sim 0 and of large q^2 behavior, corresponding to the perturbation theory up to four loops, a procedure is considered of matching the beta-function at a boundary of perturbative and non-perturbative regions. The contribution of the non-perturbative region to the gluon condensate is calculated with

UKQCD Collaboration, K. C. Bowler, B. Joó, R. D. Kenway

We present exploratory results for the hadron mass spectrum and pseudoscalar meson decay constants using mixed actions. We use improved staggered sea quarks and HYP-smeared overlap valence quarks. We obtain good signals on 10 configurations at one lattice spacing and two different sets of sea quark masses.

K. Abe

We present a measurement of the decay amplitudes and triple-product correlations in B -> phi K^* decays based on 140 fb^-1 of data recorded at the Upsilon(4S) resonance with the Belle detector at the KEKB e^+ e^- storage ring. The decay amplitudes for the different phi K^* helicity states are measured from the angular distributions of final state particles i

E. Frlez

The abBA collaboration proposes to conduct a comprehensive program of precise measurements of neutron $β$-decay coefficients $a$ (the correlation between the neutrino momentum and the decay electron momentum), $b$ (the electron energy spectral distortion term), $A$ (the correlation between the neutron spin and the decay electron momentum), and $B$ (the corre

Belle Collaboration

We report a measurement of the first and second moment of the hadronic mass distribution M_X in B -> X_c l nu decays for lepton threshold momenta ranging from 0.9 to 1.6 GeV/c in the center of mass frame. The measurement uses B Bbar events in which the hadronic decay of one B meson is fully reconstructed and a charged lepton from the decay of the other B mes

K. Abe

We report the observation of the radiative decay B+ --> K1(1270)+ gamma using a data sample of 140 fb-1 taken at the Upsilon(4S) resonance with the Belle detector at the KEKB e+e- collider. We find the branching fraction to be Br(B+ --> K1(1270)+ gamma) = (4.28 +- 0.94(stat.) +- 0.43(syst.)) x 10-5 with a statistical significance of 9.2sigma. We find no sign

K. Abe

We report search results for the flavor-changing neutral current process b --> d gamma with a data sample containing 274 million B meson pairs accumulated at the Upsilon(4S) resonance with the Belle detector at KEKB. We studied the exclusive decays B- --> rho- gamma, B0bar --> rho0 gamma, and B0bar --> omega gamma, and find no significant signal. We set an u

BABAR Collaboration, B. Aubert

We present a preliminary measurement of the CP asymmetry in singly Cabibbo-suppressed D+ -> K-K+π+ decays and in the resonant decays D+ -> ϕπ+ and D+ -> K*0 K+. We use a data sample of 79.9 fb^{-1} recorded by the BABAR detector. The Cabibbo-favored Ds+ -> K-K+π+ branching fraction is used as normalization in the measurements to reduce systematic uncertainti

E. Minguzzi

Local simultaneity conventions are mathematically represented by connections on the bundle of timelike curves that defines the frame. Those simultaneity conventions having an holonomy proportional to the Riemann tensor have a special interest since they exhibit a good global behavior in the weak field limit. By requiring that the simultaneity convention depe

Lorenzo Iorio

The possibility of analyzing the node Omega of the GP-B satellite in order to measure also the Lense-Thirring effect on its orbit is examined. This feature is induced by the general relativistic gravitomagnetic component of the Earth gravitational field. The GP-B mission has been launched in April 2004 and is aimed mainly to the measurement of the gravitomag

Alexander Haubold, John R. Kender

We introduce new techniques for extracting, analyzing, and visualizing textual contents from instructional videos of low production quality. Using Automatic Speech Recognition, approximate transcripts (H75% Word Error Rate) are obtained from the originally highly compressed videos of university courses, each comprising between 10 to 30 lectures. Text materia

Emin Martinian, Gregory W. Wornell, Ram Zamir

We consider lossy source coding when side information affecting the distortion measure may be available at the encoder, decoder, both, or neither. For example, such distortion side information can model reliabilities for noisy measurements, sensor calibration information, or perceptual effects like masking and sensitivity to context. When the distortion side

Scott A. Bender, Kevin D. Erker, Brian E. Granger

We consider the single particle correlations and momentum distributions in a gas of strongly interacting spinless 1D fermions with zero-range interactions. This system represents a fermionic version of the Tonks-Girardeau gas of impenetrable bosons as it can be mapped to a system of noninteracting 1D bosons. We use this duality to show that the T=0 single pa

E. Ben-Naim, P. L. Krapivsky

Structural properties of evolving random graphs are investigated. Treating linking as a dynamic aggregation process, rate equations for the distribution of node to node distances (paths) and of cycles are formulated and solved analytically. At the gelation point, the typical length of paths and cycles, l, scales with the component size k as l ~ k^{1/2}. Dyna

Duygu Balcan, Ayse Erzan

We have defined a new type of clustering scheme preserving the connectivity of the nodes in network ignored by the conventional Migdal-Kadanoff bond moving process. Our new clustering scheme performs much better for correlation length and dynamical critical exponents in high dimensions, where the conventional Migdal-Kadanoff bond moving scheme breaks down. I

A. B. Harris, Michael Cohen

We discuss the exact solutions of various models of the statistics of dimer coverings of a Bethe lattice. We reproduce the well-known exact results for noninteracting hard-core dimers by both a very simple geometrical argument and a general algebraic formulation for lattice statistical problems. For the Bethe lattice we also obtain the exact solution when ei

Jean-Philippe Bouchaud

This is a short review on the compatibility between (a) mean-field, mode-coupling theories of the glass transition, where potential energy landscape ideas are natural, and (b) the necessity of describing the slowing down of glassy materials in terms of a growing cooperative length, absent from mean-field descriptions. We summarize some of the outstanding que

Inseok Yang, Woowon Kang, Loren Pfeiffer, Kirk Baldwin

We report on tunneling experiment between two quantum Hall droplets separated by a nearly ideal tunnel barrier. The device is produced by cleaved edge overgrowth that laterally juxtaposes two two-dimensional electron systems across a high quality semiconductor barrier. The dramatic evolution of the tunneling characteristics is consistent with the magnetic fi

D. V. Berkov, N. L. Gorn

We demonstrate (using full-scale micromagnetic simulations) that the spin injection driven steady-state precession of a thin magnetic nanoelement exhibit a complicate transition from the quasi-macrospin to the chaotic behaviour with the increasing element size. For nanoelement parameters typical for those used experimentally we have found that the macrospin

P. Cicuta, A. R. Tajbakhsh, E. M. Terentjev

Cholesteric liquid crystal elastomers have interesting and potentially very useful photonic properties. In an ideal monodomain configuration of these materials, one finds a Bragg-reflection of light in a narrow wavelength range and a particular circular polarization. This is due to the periodic structure of the material along one dimension. In many practical

Pietro Cicuta, Ian Hopkinson

Surface Quasi-Elastic Light Scattering (SQELS) is an application of dynamic light scattering to measure the dynamics of the thermal roughness of liquid surfaces. An analysis of the spectrum of thermal fluctuations provides information on surface properties like tension and elasticity. In this work we will focus particularly on its use to study polymer or pol

S. Ingvarsson, Gang Xiao, S. S. P. Parkin, R. H. Koch

We show that magnetization damping in Permalloy, Ni80Fe20 (``Py&#39;&#39;), can be enhanced sufficiently to reduce post-switching magnetization precession to an acceptable level by alloying with the transition metal osmium (Os). The damping increases monotonically upon raising the Os-concentration in Py, at least up to 9% of Os. Other effects of alloying wit

P. Harrison, E. E. Orlova

A relationship between the maximum operating temperature of semiconductor lasers and their emission wavelength is conjectured. The conjecture is supported by a wide variety of existing experimental data for visible and infrared double heterojunction and quantum well lasers, quantum cascade lasers, as well as more esoteric devices such as Type-II antimonide-b

S. Ono, Seiki Komiya, A. N. Lavrov, Yoichi Ando

The magnetoresistance (MR) in the in-plane resistivity is measured in magnetic fields up to 55 T in lightly doped La_{2-x}Sr_{x}CuO_{4} in the Néel state (x = 0.01) and in the spin-glass state (x = 0.03) using high-quality untwinned single crystals. In both cases, a large negative MR is observed to appear when the magnetic order is established. For x = 0.01,

S. Ono, Yoichi Ando, F. F. Balakirev, J. B. Betts

We measure the magnetic-field dependence of the c-axis resistivity, ρ_c(H), in a series of Bi_{2}Sr_{2-x}La_xCuO_{6+δ} (BSLCO) single crystals for a wide range of doping using pulsed magnetic fields up to 58 T. The behavior of ρ_c(H) is examined in light of the recent determination of the upper critical field H_{c2} for this material using Nernst effect meas

L. Harnau, S. Dietrich

Density functional theory is used to study binary colloidal fluids consisting of hard spheres and thin platelets in their bulk and near a planar hard wall. This system exhibits liquid-liquid coexistence of a phase that is rich in spheres (poor in platelets) and a phase that is poor in spheres (rich in platelets). For the mixture near a planar hard wall, we f

V. I. Yukalov

A survey is given of the present state of the art in studying Bose-Einstein condensation of dilute atomic gases. The bulk of attention is focused on the principal theoretical problems, though the related experiments are also mentioned. Both uniform and nonuniform trapped gases are considered. Existing theoretical contradictions are critically analysed. A cor

Qing-rong Feng, Chinping Chen, Ying Lu, Zhang Zia

MgB2 thick film was synthesized on the stainless steel substrate by the technique of hybrid physical-chemical vapor deposition (HPCVD), using Mg ingot and B2H6 as the raw materials. The film thickness is about 10 microns. The scanning electron microscope (SEM) images reveal that it is consisting of highly dense MgB2 crystals with the size ranging from 0.2 to

R. Mélin

We propose a theoretical description of the sin(2 phi) current-phase relation in SFS junctions at the 0-$π$ cross-over obtained in recent experiments by Sellier et al. [Phys. Rev. Lett. 92, 257005 (2004)] where it was suggested that a strong decoherence in the magnetic alloy can explain the magnitude of the residual supercurrent at the 0-pi cross-over. To de

Jeremy Darling, Riccardo Giovanelli, Martha P. Haynes, Alberto D. Bolatto

We report the detection of a deep broad HI 21 cm absorption system at z = 0.78 toward the radio source [HB89] 2351+456 (4C+45.51) at z = 1.992. The HI absorption was identified in a blind spectral line survey conducted at the Green Bank Telescope spanning 0.63 < z < 1.10 toward a large sample of radio continuum sources. The HI column density is N(HI) = 2.35

Stanimir A. Metchev, Lynne A. Hillenbrand

We present first results from the Palomar Adaptive Optics Survey of Young Stars conducted at the Hale 5 m telescope. Through direct imaging we have discovered a brown dwarf and two low-mass stellar companions to the young solar-type stars HD 49197, HD 129333 (EK Dra), and V522 Per, and confirmed a previously suspected companion to RX J0329.1+0118 (Sterzik et

Donald C. Ellison, Glen P. Double

We present results from a fully relativistic Monte Carlo simulation of diffusive shock acceleration (DSA) in unmodified shocks. The computer code uses a single algorithmic sequence to smoothly span the range from nonrelativistic speeds to fully relativistic shocks of arbitrary obliquity, providing a powerful consistency check. While known results are obtaine

Michael M. Shara, Sasha Hinkley, David R. Zurek, Christian Knigge

Despite decades-old predictions of the expected presence of dozens of cataclysmic variables in the cores of globular clusters, the number of irrefutable, out-bursting candidates is still barely a handful. Using multi-wavelength, multi-epoch HST images we have produced outburst and quiescence light curves for the recently discovered large amplitude variable C

Pierre-Alain Duc, Frederic Bournaud, Frederic Masset

Among those objects formed out of collisional debris during galaxy mergers, the prominent gaseous accumulations observed near the tip of some long tidal tails are the most likely to survive long enough to form genuine recycled galaxies. Using simple numerical models, Bournaud, Duc & Masset (2003) claimed that tidal objects as massive as 10^9 Msun could only

A. P. Whitworth, H. Zinnecker

We explore the possibility that, in the vicinity of an OB star, a prestellar core which would otherwise have formed an intermediate or low-mass star may form a free-floating brown dwarf or planetary-mass object, because the outer layers of the core are eroded by the ionizing radiation from the OB star before they can accrete onto the protostar at the centre

Milan M. Cirkovic

A new solution of Fermi&#39;s paradox sketched by SF writer Karl Schroeder in his 2002. novel &#34;Permanence&#34; is critically investigated. It is argued that this solution is tightly connected with adaptationism - a widely discussed working hypothesis in evolutionary biology. Schroeder&#39;s hypothesis has important ramifications for astrobiology, SETI pr

B. P. Venemans, H. J. A. Rottgering, R. A. Overzier, G. K. Miley

We present the results of narrow-band and broad-band imaging with the Very Large Telescope of the field surrounding the radio galaxy TN J0924-2201 at z = 5.2. Fourteen candidate Ly alpha emitters with a rest-frame equivalent width of > 20 A were detected. Spectroscopy of 8 of these objects showed that 6 have redshifts similar to that of the radio galaxy. The

Yoshio Kubo

The spacetime structure of the spatially uniformly expanding universe is described in terms of a kind of global space and global time instead of the space and time we usually recognize. The global space at some instant is a space in which the global time is equal and the global time is equal to the proper time of any point moving together with the expansion

Craig A. Kulesa, Aimee L. Hungerford, Christopher K. Walker, Xiaolei Zhang

We present a comprehensive study of the rho Ophiuchi molecular cloud that addresses aspects of the physical structure and condition of the molecular cloud and its photodissociation region (PDR) by combining far-infrared and submillimeter-wave observations with a wide range of angular scale and resolution. We present 40&#39;x40&#39; maps in CO(4-3) and [CI](3

F. Iwamuro, M. Kimura, S. Eto, T. Maihara

Near-infrared spectra of four QSOs located at $z>6$ are obtained with the OH-airglow suppressor mounted on the Subaru telescope. The FeII/MgII emission-line ratios of these QSOs are examined by the same fitting algorithm as in our previous study of $z<5.3$ QSOs. The fitting results show that two out of the four $z>6$ QSOs have significant FeII emission in th

H. -Th. Janka, L. Scheck, K. Kifonidis, E. Mueller

Two- and three-dimensional simulations demonstrate that hydrodynamic instabilities can lead to low-mode (l=1,2) asymmetries of the fluid flow in the neutrino-heated layer behind the supernova shock. This provides a natural explanation for aspherical mass ejection and for pulsar recoil velocities even in excess of 1000 km/s. We propose that the bimodality of

Norbert Duechting

The observational evidence for a population of quasars powered by supermassive black holes of mass \geq 10^9 M_sun at redshifts z\geq 6 poses a great challenge for any model describing the formation of galaxies. Assuming uninterrupted accretion at the Eddington limit, seed black holes of at least 1000 M_sun are needed at z \approx 15. Here I study whether th

L. Foschini, J. A. Tomsick, J. Rodriguez, R. Walter

IGR J16320-4751 was re-discovered by IBIS/ISGRI on board INTEGRAL in early February 2003 during the observation of the black hole candidate 4U 1630-47 (PI Tomsick). This source, already observed by ASCA and BeppoSAX, belongs to the class of heavily absorbed objects (N_H > 10^23 cm^-2) that populate some arms of the Galaxy. Soon after the rediscovery by IBIS/

D. Fedorets, L. Y. Gorelik, R. I. Shekhter, M. Jonson

We consider effects of the spin degree of freedom on the nanomechanics of a single-electron transistor (SET) containing a nanometer-sized metallic cluster suspended between two magnetic leads. It is shown that in such a nanoelectromechanical SET(NEM-SET) the onset of an electromechanical instability leading to cluster vibrations and &#34;shuttle&#34; transpo

Sam Nelson

We define enhanced presentations of quandles via generators and relations with additional information comprising signed operations and an order structure on the set of generators. Such a presentation determines a virtual link diagram up to virtual moves. We list formal Reidemeister moves in which Tietze moves on the presented quandle are accompanied by corre