October 2006 arXiv papers — page 22

V. M. Shabaev, A. N. Artemyev, D. A. Glazov, I. I. Tupitsyn

The present status of quantum electrodynamics (QED) theory of heavy few-electron ions is reviewed. The theoretical results are compared with available experimental data. A special attention is focused on tests of QED at strong fields and on determination of the fundamental constants. A recent progress on calculations of the QED corrections to the parity nonc

Dirk Helbing, Anders Johansson, Joachim Mathiesen, Mogens H. Jensen

We propose a many-particle-inspired theory for granular outflows from a hopper and for the escape dynamics through a bottleneck based on a continuity equation in polar coordinates. If the inflow is below the maximum outflow, we find an asymptotic stationary solution. If the inflow is above this value, we observe queue formation, which can be described by a s

J. Berg, B. Luthi, S. Ott, J. Mann

A Particle Tracking Velocimetry experiment has been performed in a turbulent flow at intermediate Reynolds number. We present experimentally obtained stretching rates for particle pairs in the inertial range. When compensated by a characteristic time scale for coarse-grained strain we observe constant stretching. This indicates that the process of material l

M. Kitamura, D. Wentzel, A. A. Henden, J. Bennett

Since 1990, the United Nations is annually holding a workshop on basic space science for the benefit of the worldwide development of astronomy. Additional to the scientific benefits of the workshops and the strengthening of international cooperation, the workshops lead to the establishment of astronomical telescope facilities through the Official Development

Thomas Heimburg, Andrew D. Jackson

It is known that the action of general anesthetics is proportional to their partition coefficient in lipid membranes (Meyer-Overton rule). This solubility is, however, directly related to the depression of the temperature of the melting transition found close to body temperature in biomembranes. We propose a thermodynamic extension of the Meyer-Overton rule

M. Block, E. Schoell, D. Drasdo

Based on a cellular automaton model the growth kinetics and the critical surface dynamics of cell monolayers is systematically studied by variation of the cell migration activity, the size of the proliferation zone and the cell cycle time distribution over wide ranges. The model design avoids lattice artifacts and ensures high performance. The monolayer expa

P. Bambade, V. Drugakov, W. Lohmann

The ILC accelerator parameters and detector concepts are still under discussion in the world-wide community. As will be shown, the performance of the BeamCal, the calorimeter in the very forward area of the ILC detector, is very sensitive to the beam parameter and crossing angle choices. We propose here BeamCal designs for a small (0 or 2 mrad) and large (20

Brandon H. McNaughton, Rodney R. Agayan, Raoul Kopelman

We report on a new technique which was used to detect single Escherichia coli that is based on the changes in the nonlinear rotation of a magnetic microsphere driven by an external magnetic field. The presence of one Escherichia Coli bacterium on the surface of a 2.0 micron magnetic microsphere caused an easily measurable change in the drag of the system and

Masanori Sato

We show the compatibility of the theory of special relativity with the absolute reference frame with a longitudinal Doppler shift. Using two absolute velocities vA and vS, the relative velocity u is derived. Thereafter the Doppler frequency is derived using the relative velocity u. We also show the method for detecting the absolute reference frame. The repre

Tobias A. Gail, Thomas R. Hemmert

We present a calculation of the three complex form factors parametrizing the nucleon to Delta transition matrix element in the framework of chiral effective field theory with explicit Delta degrees of freedom. The interplay between short and long range physics is discussed and estimates for systematic uncertainties due to higher order effect are given.

M. S. Bhagwat, A. Holl, A. Krassnigg, C. D. Roberts

This Dyson-Schwinger equation (DSE) aperc,u highlights recent applications to mesons. It reports features of, and results for, pseudoscalar and scalar bound-state residues in vacuum polarisations, and exhibits how a restoration of chiral symmetry in meson trajectories could be manifest in a relationship between them. It also touches on nucleon studies, empha

R. V. Jolos, V. V. Voronov

In the framework of the Relativistic Mean Field Approach a pseudospin dependence of the residual forces in nuclei is considered. It is shown that this dependence is relatively weak. As a consequence, a pseudospin dependence of the particle--core coupling is weak as well. This leads to a small splitting of the pseudospin doublets produced by a vector coupling

Takashi Nakatsukasa, Kazuhiro Yabana

Nuclear dynamics of giant resonances are investigated with the real-time Skyrme TDHF method. The TDHF equation is explicitly linearized with respect to variation of single-particle wave functions. The time evolution of transition densities are calculated for giant dipole resonances. The time-dependent densities of protons and neutrons suggest that the dynami

Takashi Nakatsukasa, Makoto Ito, Kazuhiro Yabana

Using the time-dependent theory of quantum mechanics, we investigate nuclear electric dipole responses. The time evolution of a wave function is explicitly calculated in the coordinate-space representation. The particle continuum is treated with the absorbing boundary condition. Calculated time-dependent quantities are transformed into those of familiar ener

Shin Nan Yang, Guan Yeu Chen, S. S. Kamalov

A meson-exchange piN model, previously constructed using three-dimensional reduction scheme of the Bethe-Salpeter equation for a model Lagrangian involving π, η, N, Δ, rho, and σfields, is extended to energies up to 2 GeV by including the ηN channel and all the four stars πN resonances up to the F-waves. The effects of other 2 pion channels are taken into ac

Y. G. Ma, T. Z. Yan, X. Z. Cai, J. G. Chen

Anisotropic flows ($v_1$, $v_2$ and $v_4$) of light nuclear clusters are studied by a nucleonic transport model in intermediate energy heavy ion collisions. The number-of-nucleon scalings of the directed flow ($v_1$) and elliptic flow ($v_2$) are demonstrated for light nuclear clusters. Moreover, the ratios of $v_4/v_2^2$ of nuclear clusters show a constant

Y. Tsue, C. Providencia, J. da Providencia, M. Yamamura

Aspects of the phase change of the two-level pairing model are investigated in the semi-classical treatment by using the variational approch with the mixed-mode coherent state. In the classical limit, $hbar \to 0$, the sharp phase transition appears and the two phases exist in the region where the force strength is larger than a certain critical value. Howev

Alexander Sakhnovich

A nonlinear Schrödinger equation with external potential $-(t+b)^{-1}$ is considered and its explicit solutions are constructed.

Aristophanes Dimakis, Folkert Muller-Hoissen

From a 'discrete' functional zero curvature equation, functional representations of (matrix) Burgers and potential KP (pKP) hierarchies (and others), as well as corresponding Backlund transformations, can be obtained in a surprisingly simple way. With their help we show that any solution of a Burgers hierarchy is also a solution of the pKP hierarchy.

Debabrata Dutta, J K Bhattacharjee

Lotka Volterra model and its modified forms have long become a major area of interest for periodic motions in nonlinear systems with competitive species. The model given by Volterra shows that its periodicity is dependent on initial condition. This characteristics allows us to calculate the effect of periodic seasonal changes on population densities of diffe

M. Spreafico, S. Zerbini

We consider a class of singular Riemannian manifolds, the deformed spheres $S^N_k$, defined as the classical spheres with a one parameter family $g[k]$ of singular Riemannian structures, that reduces for $k=1$ to the classical metric. After giving explicit formulas for the eigenvalues and eigenfunctions of the metric Laplacian $Δ_{S^N_k}$, we study the assoc

Yves Colin de Verdiere

In the present paper which follows our previous paper ``Mathematical models for passive imaging I: general background'', we discuss the case of surface waves in a medium which is stratified near its boundary at some scale comparable to the wave length. We discuss how the propagation of such waves is governed by effective Hamiltonians on the boundary.

Yves Colin de Verdiere

Passive imaging is a new technics which has been proved to be very efficient, for example in seismology: the correlation of the noisy fields between different points is strongly related to the Green function of the wave propagation. The aim of this paper is to provide a mathematical context for this approach and to show, in particular, how the methods of sem

Johan Beumee

This paper models the classical diffusion of a main particle through a heatbath by means of a pre-limit microscopic representation of its drifted momentum and energy transfers at collision times. The collision point linear interpolated path can be approximated by the solution to the "inscribed" continuous stochastic differential equation using the sa

Konstantin Borovkov, David Odell

We introduce a new class of spatial-temporal point processes based on Voronoi tessellations. At each step of such a process, a point is chosen at random according to a distribution determined by the associated Voronoi cells. The point is then removed, and a new random point is added to the configuration. The dynamics are simple and intuitive and could be app

Huyi Hu, Anna Talitskaya

We construct a smooth hyperbolic volume preserving diffeomorphism on a four dimensional compact Riemannian manifold which has countably many ergodic components and is arbitrarily close to the identity map.

Alex James Bene

A closed formula is obtained for the integral $\int_{\mathcal{\bar{H}}_g^1}κ_{1}ψ^{2g-2}$ of tautological classes over the locus of hyperelliptic Weierstraß points in the moduli space of curves. As a corollary, a relation between Hodge integrals is obtained. The calculation utilizes the homeomorphism between the moduli space of curves $\mathcal{M}_{g,1}$ and

Jose F. Alves, Maria Carvalho, Jorge Milhazes Freitas

We consider the family of Henon maps in the plane and show that the SRB measures vary continuously in the weak* topology within the set of Benedicks-Carleson parameters.

Bruce Reznick

The Stern sequence (s(n)) is defined by s(0) = 0, s(1) = 1, s(2n) = s(n), s(2n+1) = s(n) + s(n+1). Stern showed in 1858 that gcd(s(n),s(n+1)) = 1, and that for every pair of relatively prime positive integers (a,b), there exists a unique n so that s(n) = a and s(n+1) = b. We show that, in a strong sense, the average value of s(n)/s(n+1) is 3/2, and that for

Julien Roques

By using meromorphic "characters" and "logarithms" built up from Euler's Gamma function, and by using convergent factorial series, we will give, in a first pat, a "normal form" to the solutions of a singular regular system. It will enable us to define a connexion matrix for a regular singular system. Following one of Birkhoff'

W. J. Zakrzewski

We show that many surfaces in $\R^{N^2-1}$ can be generated by harmonic maps of $S^2\to CP^{N-1}$. These surfaces are based on the projectors in $CP^{N-1}$ which describe maps of $S^2\to CP^{N-1}$. In the case when these maps form the Veronese sequence all the surfaces have constant curvature.

Karlheinz Gröchenig, Ziemowit Rzeszotnik, Thomas Strohmer

The finite section method is a classical scheme to approximate the solution of an infinite system of linear equations. We present quantitative estimates for the rate of the convergence of the finite section method on weighted $\ell ^p$-spaces. Our approach uses recent results from the theory of Banach algebras of matrices with off-diagonal decay. Furthermore

Arne B. Sletsjoe

We study finite dimensional representations of the projective modular group. Various explicit dimension formulas are given.

Virgil U. Pierce

Bauer and Itzykson showed that associated to each labeled map embedded on an oriented Riemann surface there was a group generated by a pair of permutations. From this result an algorithm may be constructed for enumerating labeled maps, and this construction is easily augmented to bin the numbers by the genus of the surface the map is embedded in. The results

Marie Cottrell, Patrick Letrémy

The Kohonen algorithm (SOM, Kohonen,1984, 1995) is a very powerful tool for data analysis. It was originally designed to model organized connections between some biological neural networks. It was also immediately considered as a very good algorithm to realize vectorial quantization, and at the same time pertinent classification, with nice properties for vis

Marie Cottrell, Smail Ibbou, Patrick Letrémy

It is well known that the SOM algorithm achieves a clustering of data which can be interpreted as an extension of Principal Component Analysis, because of its topology-preserving property. But the SOM algorithm can only process real-valued data. In previous papers, we have proposed several methods based on the SOM algorithm to analyze categorical data, which

László Tóth

We determine the asymptotic density $δ_k$ of the set of ordered $k$-tuples $(n_1,...,n_k)\in \N^k, k\ge 2$, such that there exists no prime power $p^a$, $a\ge 1$, appearing in the canonical factorization of each $n_i$, $1\le i\le k$, and deduce asymptotic formulae with error terms regarding this problem and analogous ones. We give numerical approximations of

László Tóth

Let $d,n$ be positive integers and $S$ be an arbitrary set of positive integers. We say that $d$ is an $S$-divisor of $n$ if $d|n$ and gcd $(d,n/d)\in S$. Consider the $S$-convolution of arithmetical functions given by (1.1), where the sum is extended over the $S$-divisors of $n$. We determine the sets $S$ such that the $S$-convolution is associative and pre

Xiwei Liu Tianping Chen

In this paper, new schemes to synchronize linearly or nonlinearly coupled chaotic systems with an adaptive coupling strength are proposed. Unlike other adaptive schemes, which synchronize coupled chaotic systems to a special trajectory (or an equilibrium point) of the uncoupled node by adding negative feedbacks adaptively; here, adaptive schemes for the coup

Naihong Hu, Dong Liu

The universal central extensions and their extension kernels of the matrix Lie superalgebra sl(m, n, A), the Steinberg Lie superalgebra st(m, n, A) in category {\bf SLeib} of Leibniz superalgebras are determined under a weak assumption (compared with \cite{MP}) using the first Hochschild homology and the first cyclic homology group.

Guangxiang Su, Weiping Zhang

We generalize a theorem of Bismut-Zhang, which extends the Cheeger-Mueller theorem on Ray-Singer torsion and Reidemeister torsion, to the case where the flat vector bundle over a closed manifold carries a nondegenerate symmetric bilinear form. As a consequence, we prove the Burghelea-Haller conjecture which gives an analytic interpretation of the Turaev tors

Xun Dong

Zaslavsky conjectures that the bounded complex of a simple hyperplane arrangement is homeomorphic to a ball. We prove this conjecture for the more general uniform affine oriented matroids.

Kiran S. Kedlaya

As a simple corollary of a highly general framework for differential and difference Galois theory introduced by Y. Andre, we formulate a version of the Galois correspondence that applies over a difference field with arbitrary field of constants.

Nathan Geer, Bertrand Patureau-Mirand

In this paper we construct a multivariable link invariant arising from the quantum group associated to the special linear Lie superalgebra sl(2|1). The usual quantum group invariant of links associated to (generic) representations of sl(2|1) is trivial. However, we modify this construction and define a nontrivial link invariant. This new invariant can be tho

Fabrizio Catanese, Roberto Pignatelli

In the present paper we consider fibrations $f: S \ra B$ of an algebraic surface onto a curve $B$, with general fibre a curve of genus $g$. Our main results are: 1) A structure theorem for such fibrations in the case $g=2$ 2) A structure theorem for such fibrations in the case $g=3$ and general fibre nonhyperelliptic 3) A theorem giving a complete descriptio

B. Toen

The main purpose of this work is the study of the homotopy theory of dg-categories up to quasi-equivalences. Our main result provides a natural description of the mapping spaces between two dg-categories $C$ and $D$ in terms of the nerve of a certain category of $(C,D)$-bimodules. We also prove that the homotopy category $Ho(dg-Cat)$ is cartesian closed (i.e

Brian Batell, Andrew Larkoski

We examine the analogue one-dimensional quantum mechanics problem associated with bulk scalars and fermions in a slice of AdS_5. The ``Schroedinger'' potential can take on different qualitative shapes depending on the values of the mass parameters in the bulk theory. Several interesting correlations between the shape of the Schroedinger potential and

Matteo Beccaria, Carmine Ortix

We study the strong coupling limit of AdS/CFT correspondence in the framework of a recently proposed fermionic formulation of the Bethe Ansatz equations governing the gauge theory anomalous dimensions. We provide examples of states that do not follow the Gubser-Klebanov-Polyakov law at large 't Hooft coupling $λ$, in contrast with recent results on the q

V. Mateu

Since order parameter of the chiral symmetry breaking Green Functions are a useful link between the OPE expansion and chiral perturbation theory we perform a calculation to the NLO in alpha_s, working in the chiral limit, for all the 2 and 3 point ones. These Green Functions have no perturbative term in the chiral limit and thence their main contribution com

Gabriel Sanchez-Colon, Augusto Garcia

Our previous analysis on the contributions of mirror matter admixtures in ordinary hadrons to K_L to gamma gamma is extended to study the relevance of such contributions to the K_L to mu^+ mu^- rare decay. The mixing angle of the admixtures previously determined to describe the enhancement phenomenon in two body non-leptonic decays of strange hadrons is used

Subhash Chaturvedi, Virendra Gupta, Gabriel Sanchez-Colon

It is shown how the two experimentally measurable properties of the mixing matrix $V$, the asymmetry Delta(V)=|V_{12}|^2- |V_{21}|^2 of V with respect to the main diagonal and the Jarlskog invariant J(V)=Im(V_{11}V_{12}^*V_{21}^*V_{22}), can be exploited to obtain constraints on possible structures of mass matrices in the quark sector. Specific mass matrices

Gabriel Sanchez-Colon, Augusto Garcia

We extend our previous analysis on the symmetry limit properties of non-leptonic and weak radiative decay amplitudes of hyperons in a scheme of mirror matter admixtures in physical hadrons to include the two-body non-leptonic decays of $Ω^-$ and the two photon and two pion decays of kaons. We show that the so-called parity-conserving amplitudes predicted for

William Marciano, Zohreh Parsa

Effects of the Leptonic CP violating phase,δ, on 3 generation neutrino oscillation rates and asymmetries are discussed. A figure of merit argument is used to show that our ability to measure the phase δis rather insensitive to the value of θ_{13} (for \sin^22θ_{13}\gsim0.01) as well as the detector distance (for very long oscillation baselines). Using a stud

P. Gonzalez, J. Vijande, A. Valcarce, H. Garcilazo

We show that nonstrange baryon resonances can be classified according to multiplets of $SU(4)\otimes O(3)$. We identify spectral regularities and degeneracies that allow us to predict the high spin spectrum from 2 to 3 GeV.

J. R. Espinosa, J. M. No

Loops of the scalar particles present in Little Higgs models generate radiatively scalar operators that have been overlooked before in Little Higgs analyses. We compute them using a technique, recently proposed to deal with scalar fluctuations in non-linear sigma models, that greatly simplifies the calculation. In particular models some of these operators ar

D. Cabrera, R. Rapp

We study the evolution of heavy quarkonium states with temperature in a Quark-Gluon Plasma by evaluating an in-medium Q\bar{Q} T-matrix within a reduced Bethe-Salpeter equation in S- and P-wave channels. The interaction kernel is extracted from finite-temperature QCD lattice calculations of the singlet free energy of a Q\bar{Q} pair. Quarkonium bound states

B. A. Kniehl

We review recent progress in the development of an approach valid to any order which unifies the fixed-order DGLAP evolution of fragmentation functions at large x with soft-gluon logarithmic resummation at small x. At leading order, this approach, implemented with the Double Logarithmic Approximation, reproduces exactly the Modified Leading Logarithm Approxi

Antonio Vairo

I review recent progress in heavy quarkonium physics from an effective field theory perspective. In this unifying framework, I discuss advances in perturbative calculations for low-lying quarkonium observables and in lattice calculations for high-lying ones, and progress and lasting puzzles in quarkonium production.

Junji Hisano, Shigeki Matsumoto, Minoru Nagai, Osamu Saito

We point out that thermal relic abundance of the dark matter is strongly altered by a non-perturbative effect called the Sommerfeld enhancement, when constituent particles of the dark matter are non-singlet under the SU(2)_L gauge interaction and much heavier than the weak gauge bosons. Typical candidates for such dark matter particles are the heavy wino- an

Wojciech Krolikowski

A search for the parameter constraint in the three-parameter empirical mass formula proposed recently for active neutrinos is described. Without any parameter constraint the formula is a formal transformation of three free parameters into three neutrino masses or vice versa, giving no numerical predictions for the masses. But, this is a very special transfor

J. W. F. Valle

I briefly discuss the role of neutrinos as probes in astroparticle physics and review the status of neutrino oscillation parameters as of June 2006, including recent fluxes, and latest SNO, K2K and MINOS results. I comment on the origin of neutrino masses in seesaw-type and low-scale models and mention some of their experimental signals.

Elvira Gamiz, Matthias Jamin, Antonio Pich, Joaquim Prades

We report on recent work to determine the CKM matrix element |V_{us}| using strange hadronic τdecay data. We use the recent OPAL update of the strange spectral function, while on the theory side we update the dimension-two perturbative contribution including the recently calculated α_s^3 terms. Our result |V_{us}|=0.2220 \pm 0.0033 is already competitive wit

Carlos Pena

I report on the application of tmQCD techniques to the computation of hadronic matrix elements of four-fermion operators. Emphasis is put on the computation of $B_K$ in quenched QCD performed by the ALPHA Collaboration. The extension of tmQCD strategies to the study of neutral $B$-meson mixing is briefly discussed. Finally, some remarks are made concerning p

David d'Enterria

We present a summary of the physics of gluon saturation and non-linear QCD evolution at small values of parton momentum fraction $x$ in the proton and nucleus in the context of recent experimental results at HERA and RHIC. The rich physics potential of low-x studies at the LHC, especially in the forward region, is discussed and some benchmark measurements in

P. Azzurri

Results on W-pair productions at LEP2 are reviewed and their consistency with standard electroweak expectations is summarised. Special interest is given to measurements of W polarisation, and to new studies of spin and decay-plane correlations among the W pairs.

A. Das, N. Tariq, R. M. W. Woodside

Spherically symmetric cosmological equations in the usual FLRW coordinates are explored, with different sources. The first couples a perfect fluid with a quintessence scalar field and the second couples a perfect fluid to a tachyonic scalar field. In both cases, in the inflationary regime, the scale factor a(t) and its first two time derivatives are positive

N. E. J. Bjerrum-Bohr, John F. Donoghue, Barry R. Holstein

We use results by Kirilin to show that in general relativity the nonleading terms in the energy-momentum tensor of a particle depends on the parameterization of the gravitational field. While the classical metric that is calculated from this source, used to define the leading long-distance corrections to the metric, also has a parameteriztion dependence, it

Yongli Ping, Hongya Liu, Lixin Xu

We use $(4+1)$ split to derive the 4D induced energy density $ρ$ and pressure $p$ of the $5D$ Ricci-flat cosmological solutions which are characterized by having a bounce instead of a bang. The solutions contain two arbitrary functions of time $t$ and, therefore, are mathematically rich in giving various cosmological models. By using four known energy condit

Elad Hazan

Lagrangian relaxation and approximate optimization algorithms have received much attention in the last two decades. Typically, the running time of these methods to obtain a $ε$ approximate solution is proportional to $\frac{1}{ε^2}$. Recently, Bienstock and Iyengar, following Nesterov, gave an algorithm for fractional packing linear programs which runs in $\

Tuomo Kakkonen, Niko Myller, Erkki Sutinen

Latent Semantic Analysis (LSA) is a widely used Information Retrieval method based on "bag-of-words" assumption. However, according to general conception, syntax plays a role in representing meaning of sentences. Thus, enhancing LSA with part-of-speech (POS) information to capture the context of word occurrences appears to be theoretically feasible e

Jeremy Avigad, Yimu Yin

In 1985, van den Dries showed that the theory of the reals with a predicate for the integer powers of two admits quantifier elimination in an expanded language, and is hence decidable. He gave a model-theoretic argument, which provides no apparent bounds on the complexity of a decision procedure. We provide a syntactic argument that yields a procedure that i

Tuomo Kakkonen

DepAnn is an interactive annotation tool for dependency treebanks, providing both graphical and text-based annotation interfaces. The tool is aimed for semi-automatic creation of treebanks. It aids the manual inspection and correction of automatically created parses, making the annotation process faster and less error-prone. A novel feature of the tool is th

A. M. Mora, J. J. Merelo, C. Millan, J. Torrecillas

In this paper we propose a Multi-Objective Ant Colony Optimization (MOACO) algorithm called CHAC, which has been designed to solve the problem of finding the path on a map (corresponding to a simulated battlefield) that minimizes resources while maximizing safety. CHAC has been tested with two different state transition rules: an aggregative function that co

Pavel A. Belov, Yan Zhao, Sunil Sudhakaran, Akram Alomainy

An experimental investigation of sub-wavelength imaging by a wire medium slab is performed. A complex-shaped near field source is used in order to test imaging performance of the device. It is demonstrated that the ultimate bandwidth of operation of the constructed imaging device is 4.5% that coincides with theoretical predictions [Phys. Rev. E 73, 056607 (2

M. V. Feigel'man, L. B. Ioffe, V. E. Kravtsov, E. A. Yuzbashyan

We develop a theory of a pseudogap state appearing near the superconductor-insulator transition in strongly disordered metals with attractive interaction. We show that such an interaction combined with the fractal nature of the single particle wave functions near the mobility edge leads to an anomalously large single particle gap in the superconducting state

D. Ryvkine, M. I. Dykman

We study a parametrically modulated oscillator that has two stable states of vibrations at half the modulation frequency $ω_F$. Fluctuations of the oscillator lead to interstate switching. A comparatively weak additional field can strongly affect the switching rates, because it changes the switching activation energies. The change is linear in the field ampl

Pramod Kumar, Niraj K. Singh, K. G. Suresh, A. K. Nigam

We report the magnetocaloric effect in terms of isothermal magnetic entropy change as well as adiabatic temperature change, calculated using the heat capacity data. Using the zero field heat capacity data, the magnetic contribution to the heat capacity has been estimated. The variations in the magnetocaloric behavior have been explained on the basis of the m

M. Giura, R. Fastampa, S. Sarti, N. Pompeo

We consider the problem of c-axis transport in double-layered cuprates, in particular with reference to Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8+δ}$ compounds. We exploit the effect of the two barriers on the thermal and tunnel transport. The resulting model is able to describe accurately the normal state c-axis resistivity in Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8+δ}$, fro

Tobias Ambjornsson, Suman K Banik, Michael A Lomholt, Ralf Metzler

After crossing an initial barrier to break the first base-pair (bp) in double-stranded DNA, the disruption of further bps is characterized by free energies between less than one to a few kT. This causes the opening of intermittent single-stranded bubbles. Their unzipping and zipping dynamics can be monitored by single molecule fluorescence or NMR methods. We

Jialin Wu

The nature may be disclosed that the glass transition is only determined by the intrinsic 8 orders of instant 2-D mosaic geometric structures, without any presupposition and relevant parameter. An interface excited state on the geometric structures comes from the additional Lindemann distance increment, which is a vector with 8 orders of relaxation times, 8

Gwennou Coupier, Michel Saint Jean, Claudine Guthmann

We show that the diffusion of a single file of particles moving in a fluctuating modulated 1D channel is enhanced with respect to the one in a bald pipe. This effect, induced by the fluctuations of the modulation, is favored by the incommensurability between the channel potential modulation and the moving file periodicity. This phenomenon could be of importa

A. M. Puertas, M. Fuchs, M. E. Cates

We present simulation results addressing the phenomena of colloidal gelation induced by attractive interactions. The liquid-gas transition is prevented by the glass arrest at high enough attraction strength, resulting in a colloidal gel. The dynamics of the system is controlled by the glass, with little effect of the liquid-gas transition. When the system se

E. van Heumen, R. Lortz, A. B. Kuzmenko, F. Carbone

In- and out-of-plane optical spectra and specific heat measurements for the single layer cuprate superconductor Hg-1201 at optimal doping (Tc = 97 K) are presented. Both the in-plane and out-of-plane superfluid density agree well with a recently proposed scaling relation rho_{s}=sigma_{dc}T_{c}. It is shown that there is a superconductivity induced increase

A. S. Moskvin

We revisit a problem of Dzyaloshinsky-Moriya antisymmetric exchange coupling for a single bond in cuprates specifying the local spin-orbital contributions to Dzyaloshinsky vector focusing on the oxygen term. The Dzyaloshinsky vector and respective weak ferromagnetic moment is shown to be a superposition of comparable and, sometimes, competing local Cu and O

T. Figielski, T. Wosinski, A. Morawski, A. Makosa

We show a novel magneto-resistive effect that appears in lithographically shaped, three-arm nanostructure, fabricated from ferromagnetic (Ga,Mn)As layers. The effect, related to a rearrangement of magnetic domain walls between different pairs of arms in the structure, reveals as a dependence of zero-field resistance on the direction of previously applied mag

V. R. Ohanyan, L. N. Ananikyan, N. S. Ananikian

The lattice spin model with $Q$--component discrete spin variables restricted to have orientations orthogonal to the faces of $Q$-dimensional hypercube is considered on the Bethe lattice, the recursive graph which contains no cycles. The partition function of the model with dipole--dipole and quadrupole--quadrupole interaction for arbitrary planar graph is p

Juan Colmenero, Arturo Narros, Fernando Alvarez, Arantxa Arbe

We present fully atomistic Molecular Dynamics simulation results on a main-chain polymer, 1,4-Polybutadiene, in the merging region of the $α$- and $beta$-relaxations. A real space analysis reveals the occurrence of localized motions (``$β$-like'') in addition to the diffusive structural relaxation. A molecular approach provides a direct connection be

P. Buonsante, R. Franzosi, V. Penna

We analyze thoroughly the mean-field dynamics of a linear chain of three coupled Bose-Einstein condensates, where both the tunneling and the central-well relative depth are adjustable parameters. Owing to its nonintegrability, entailing a complex dynamics with chaos occurrence, this system is a paradigm for longer arrays whose simplicity still allows a thoro

Naomichi Hatano, Ryoen Shirasaki, Hiroaki Nakamura

We argue that a pseudo-one-dimensional electron gas is magnetized when a voltage bias is applied with the Fermi level tuned to be in the energy gap generated by a spin-orbit interaction. The magnetization is an indication of spin-carrying currents due to the spin-orbit interaction. The origin of the magnetization, however, is essentially different from the &

Niels Asger Mortensen, Sanshui Xiao, Didier Felbacq

We consider meta materials made from a two-dimensional dielectric rod-type photonic crystal. The magnetic response is studied within the recently developed homogenization theory and we in particular study the effects of topology and inhomogeneous broadening. While topology itself mainly affects the Mie resonance frequency we find that the dispersion in the t

Serkan Zorba, Yonathan Shapir, Yongli Gao

The growth mechanism of pentacene film formation on SiO2 substrate was investigated with a combination of atomic force microscopy measurements and numerical modeling. In addition to the diffusion-limited aggregation (DLA) that has already been shown to govern the growth of the ordered pentacene thin films, it is shown here for the first time that the Schwoeb

J. H. Lee, A. O. Sousa, E. J. R. Parteli, H. J. Herrmann

We model formation and evolution of transverse dune fields. In the model, only the cross section of the dune is simulated. The only physical variable of relevance is the dune height, from which the dune width and velocity are determined, as well as phenomenological rules for interaction between two dunes of different heights. We find that dune fields with no

E. J. R. Parteli, V. Schwaemmle, H. J. Herrmann, L. H. U. Monteiro

In this work, we report measurements of the height profile of transverse dunes in the coastal dune field known as ``Lençóis Maranhenses'', northeastern Brazil. Our measurements show that transverse dunes with approximately the same height present a variable brink position relative to the crest, in contrast to the case of barchan dunes. Based on our f

L. Turban

We study the statistics of column-convex lattice animals generated by the stacking of squares on a staircase with step height p. We calculate the number of animals with area k living on l stairs. The total number of animals with area k is given by the generalized Fibonacci number F_p(k). Exact results for the mean length and mean height of animals with area

E. D. Grundstrom, S. M. Caballero-Nieves, D. R. Gies, W. Huang

We present the results of an H-alpha monitoring campaign on the BeXRB and microquasar system LS I +61 303. We use radial velocity measurements of HeI lines in our spectra to re-evaluate the orbital elements and to better establish the time of periastron. We list equivalent widths and other parameters for the H-alpha emission line and discuss the orbital phas

Konrad Kuijken

We describe a new technique for measuring accurate galaxy colours from images taken under different seeing conditions. The method involves two ingredients. First we define the Gaussian-aperture-and-PSF flux, which is the Gaussian-weighted flux a galaxy would have if it were observed with a Gaussian PSF. This theoretical aperture flux is independent of the PS

Robert A. Crain, Vincent R. Eke, Carlos S. Frenk, Adrian Jenkins

We investigate the baryon fraction in dark matter haloes formed in non-radiative gas-dynamical simulations of the LambdaCDM cosmogony. By combining a realisation of the Millennium Simulation (Springel et al.) with a simulation of a smaller volume focussing on dwarf haloes, our study spans five decades in halo mass, from 10^10 Msun/h to 10^15 Msun/h. We find

Alexis Brandeker, Ray Jayawardhana, Valentin D. Ivanov, Radostin Kurtev

Binary properties are an important diagnostic of the star and brown dwarf formation processes. While wide binaries appear to be rare in the sub-stellar regime, recent observations have revealed Ophiuchus 162225-240515 (2MASS J16222521-2405139) as a likely young ultra-low-mass binary with an apparent separation of ~240 AU. Here, we present low-resolution near

Gary Steigman

Big Bang Nucleosynthesis (BBN) and the Cosmic Background Radiation (CBR) provide complementary probes of the early evolution of the Universe and of its particle content. Neutrinos play important roles in both cases, influencing the primordial abundances of the nuclides produced by BBN during the first 20 minutes as well as the spectrum of temperature fluctua

K. Beuermann

Barnes-Evans type relations provide an empirical relationship between the surface brightness of stars and their color. They are widely used for measuring the distances to stars of known radii, as the Roche-lobe filling secondaries in cataclysmic variables (CVs). The calibration of the surface brightness of field dwarfs of near-solar metalicity with spectral