January 2006 arXiv papers — page 28

Sorin Bastea

We present molecular dynamics simulation results for the viscosity and mutual diffusion constant of a strongly asymmetric binary ionic mixture (BIM). We compare the results with available theoretical models previously tested for much smaller asymmetries. For the case of viscosity we propose a new predictive framework based on the linear mixing rule, while fo

Mara Felici, Valerio Lucarini, Antonio Speranza, Renato Vitolo

A baroclinic model for the atmospheric jet at middle-latitudes is used as a stochastic generator of time series of the total energy of the system. Statistical inference of extreme values is applied to yearly maxima sequences of the time series, in the rigorous setting provided by extreme value theory. In particular, the Generalized Extreme Value (GEV) family

I. F. Barna, J. Wang, J. Burgdoerfer

We investigate two-photon double ionization of helium by intense ($10^{15} W/cm^2$) ultrashort ($\approx 300$ as) soft X-ray pulses (E = 91.6 eV). The time-dependent two-electron Schrödinger equation is solved using a coupled channel method. We show that for ultrashort pulses the angular distribution of ejected electrons depends on the pulse duration and pro

Irina Novikova, David F. Phillips, Alexander S. Zibrov, Ronald L. Walsworth

We report an experimental comparison of three-photon-absorption resonances (known as "N-resonances") for the D_1 and D_2 optical transitions of thermal 87Rb vapor. We find that the D_2 N-resonance has better contrast, a broader linewidth, and a more symmetric lineshape than the D_1 N-resonance. Taken together, these factors imply superior performance

Jose B. Almeida

Monogenic functions are functions of null vector derivative and are here analysed in the geometric algebra of 5-dimensional spacetime, G(4,1), in order to derive several laws of fundamental physics. The paper introduces the working algebra and the definition of monogenic functions, showing that these generate two 4-dimensional spaces, one with Euclidean sign

D. Sarmah, M. Tessarotto, M. Salimullah

The charge reduction effect, produced by the nonlinear Debye screening of high-Z charges occuring in strongly-coupled plasmas, is investigated. An analytic asymptotic expression is obtained for the charge reduction factor which determines the Debye-Hueckel potential generated by a charged test particle. Its relevant parametric dependencies are analyzed and s

S. Eden, J. Tabet, K. Samraoui, S. Louc

Absolute dissociation cross sections are reported for Hn+ clusters of varied mass (n = 3, 5, ..., 35) following collisions with He atoms at 60 keV / amu. Initial results have been published in a previous brief report for a smaller range of cluster sizes [Ouaskit et al., Phys. Rev. A 49, 1484 (1994)]. The present extended study includes further experimental r

O. M. Podvigina

We consider stability of steady convective flows in a horizontal layer with stress-free boundaries, heated below and rotating about the vertical axis, in the Boussinesq approximation (the Rayleigh-Benard convection). The flows under consideration are convective rolls or square cells, the latter being asymptotically equal to the sum of two orthogonal rolls of

O. M. Podvigina

We define center manifold as usual as an invariant manifold, tangent to the invariant subspace of the linearization of the mapping defining a continuous dynamical system, but the center subspace that we consider is associated with eigenvalues with small but not necessarily zero} real parts. We prove existence and smoothness of such center manifold assuming t

B. G. Sidharth

Early string theory described Bosonic particles at the real life Compton scale. Later developments to include Fermions initiated by Ramond and others have lead through Quantum Super Strings to M-theory operating at the as yet experimentally unattainable Planck scale. We describe an alternative route from Bosonic Strings to Fermions, by directly invoking a no

Igor Goychuk, Peter Hanggi

We consider an exactly tractable model of the Kramers type for the voltage-dependent gating dynamics of single ion channels. It is assumed that the gating dynamics is caused by the thermally activated transitions in a bistable potential. Moreover, the closed state of the channel is highly degenerate and embraces the whole manifold of closed substates. Openin

I. Goychuk, P. Hanggi, J. L. Vega, S. Miret-Artes

Stochastic Resonance in single voltage-dependent ion channels is investigated within a three state non-Markovian modeling of the ion channel conformational dynamics. In contrast to a two-state description one assumes the presence of an additional closed state for the ion channel which mimics the manifold of voltage-independent closed subconformations (inacti

A. Raspereza

A Particle Flow Algorithm (PFA) with the minimized dependence on the detector geometry is presented. Current PFA implementation includes procedures of the track reconstruction, calorimeter clustering, and individual particle reconstruction and is meant as a tool for the optimization of the International e+e- Linear Collider detector.

Norihito Toyota

We have proposed two new dynamic networks where two node are swapped each other, and showed that the both networks behave as a small world like in the average path length but can not make any effective discussions on the clustering coefficient because of the topological invariant properties of the networks. In this article we introduce a new index, "hamm

G. Molchan, T. Kronrod

The optimal scaling problem for the time t(LxL) between two successive events in a seismogenic cell of size L is considered. The quantity t(LxL) is defined for a random cell of a grid covering a seismic region G. We solve that problem in terms of a multifractal characteristic of epicenters in G known as the tau-function or generalized fractal dimensions; the

Rodolfo A. Diaz, William J. Herrera, R. Martinez

We present some formulae for the moments of inertia of homogeneous solids of revolution in terms of the functions that generate the solids. The development of these expressions exploits the cylindrical symmetry of these objects, and avoids the explicit use of multiple integration, providing an easy and pedagogical approach. The explicit use of the functions

V. V. Ezhela, Yu. V. Kuyanov, V. N. Larin, A. S. Siver

It is argued that the CODATA recommended values of the fundamental physical constants could not be used as the reference data in searching the hypothetical space-time variations of the fundamental physical constants. It is shown that the CODATA data permanently suffers a loss of self-consistency of the released data due to unjustified over-rounding of their

Andrew W. Steiner

The presence of quark matter in neutron stars may affect several neutron star observables and the neutrino signal in core-collapse supernovae. These observables are sensitive to the phase of quark matter that is present in compact objects. We present the first calculation of the phase structure of dense quark matter which includes a six-fermion color-superco

Y. Funaki, A. Tohsaki, H. Horiuchi, P. Schuck

In order to discuss the spatial extention of the second 0+ state of 12C (Hoyle state), we analyze the inelastic form factor of electron scattering to the Hoyle state, which our 3 alpha condensate wave function reproduces very well like previous 3 alpha RGM/GCM models. The analysis is made by varying the size of the Hoyle state artificially. As a result, we f

Giampaolo Co'

Merits and faults of the effective theory Random Phase Approximations are discussed in the perspective of its use in the prediction of neutrino-nucleus cross sections.

V. P. Popov, V. N. Pomerantsev

The elastic scattering, Stark transitions and Coulomb deexcitation of excited antiprotonic hydrogen atom in collisions with hydrogenic atom have been studied in the framework of the fully quantum-mechanical close-coupling method for the first time. The total cross sections $σ_{nl \to n'l'}(E)$ and averaged on the initial angular momentum $l$ cross se

Yu. N. Pokotilovski

Fast neutron-mirror neutron (n-n') oscillations were proposed recently as the explanation of the GZK puzzle. We discuss possible laboratory experiments to search for such oscillaions and to improve the present very weak constraints on the value of the n-n' oscillation probability.

A. Heusler, G. Graw, R. Hertenberger, F. Riess

Inelastic proton scattering via isobaric analog resonances allows to derive rather complete information about neutron particle-hole states. We applied this method to the doubly-magic nucleus 208Pb by measuring angular distributions of 208Pb(p, p') on top of the isobaric analog resonances in 209Bi with the Q3D magnetic spectrograph at München. We identify

Mikhail V. Ivanchenko, Grigory V. Osipov, Vladimir D. Shalfeev, Jurgen Kurths

We report on the origin of synchronized bursting dynamics in various networks of neural spiking oscillators, when a certain threshold in coupling strength is exceeded. These ensembles synchronize at relatively low coupling strength and lose synchronization at stronger coupling via spatio-temporal intermittency. The latter transition triggers multiple-timesca

S. Albeverio, H. Gottschalk, M. W. Yoshida

Euclidean quantum fields obtained as solutions of stochastic partial pseudo differential equations driven by a Poisson white noise have paths given by locally integrable functions. This makes it possible to define a class of ultra-violet finite local interactions for these models (in any space-time dimension). The corresponding interacting Euclidean quantum

Todor Popov

Manin associated to a quadratic algebra (quantum space) the quantum matrix group of its automorphisms. This Talk aims to demonstrate that Manin's construction can be extended for quantum spaces which are non-quadratic homogeneous algebras. Here given a regular Artin-Schelter algebra of dimension 3 we construct the quantum group of its symmetries, i.e., t

S. McMath, F. Crabbe, D. Joyner

In this partly expository paper, we discuss three results. (1) That the two-sided continued fraction of the normalized square root (an important part of the SQUFOF algorithm) has several very attractive properties - periodicity, a symmetry point corresponding to a factorization of $N$, and so on. (2) The infrastructure distance formula. (3) A method for para

Ruslan Sharipov

Some aspects of Dirac spinors are resumed and studied in order to interpret mathematically the P and T operations in a gravitational field.

S. Morel

In this work, we calculate the trace of a power of the Frobenius endomorphism on the fibers of the intersection complex of the Baily-Borel compactification of a Shimura variety associated to a unitary group over Q. Our main tool is Pink's theorem about the restriction to the strata of the Baily-Borel compactification of the direct image of a local system

Dan Edidin, Zhenbo Qin

We study the Gromov-Witten and Donaldson-Thomas correspondence conjectured in [MNOP1, MNOP2], for trivial elliptic fibrations. In particular, we verify the Gromov-Witten and Donaldson-Thomas correspondence for primary fields when the threefold is $E \times S$ where $E$ is a smooth elliptic curve and $S$ is a smooth surface with numerically trivial canonical

Maurice Pouzet, Nicolas M. Thiéry

The profile of a relational structure R is the function phi_R which counts for every integer n the number, possibly infinite, phi_R(n) of substructures of R induced on the n-element subsets, isomorphic substructures being identified. Several graded algebras can be associated with R in such a way that the profile of R is simply the Hilbert function. An exampl

Alessia Cattabriga, Michele Mulazzani

Let F a closed connected orientable surface bounding a genus g handlebody H. In this paper we find a finite set of generators for the subgroup E(2,g) of the pure mapping class group of the twice punctured torus PMCG(2,g), consisting of the isotopy classes of homeomorphisms of F which admit an extension to H keeping a properly embedded trivial arc fixed. This

Mark Goresky, Robert Kottwitz, Robert MacPherson

This paper gives combinatorial formulas for discrete series constants, both stable and unstable, on real reductive groups. It also carries out one step of the comparison of the topological trace formula for Hecke operators with Arthur's trace formula for Hecke operators, the step in which the topological terms are combined in such a way that stable discr

D. Arnaudon, J. Avan, L. Frappat, E. Ragoucy

From the defining exchange relations of the A_{q,p}(gl_{N}) elliptic quantum algebra, we construct subalgebras which can be characterized as q-deformed W_N algebras. The consistency conditions relating the parameters p,q,N and the central charge c are shown to be related to the singularity structure of the functional coefficients defining the exchange relati

N. Kolev, N. Nenov

We improve the previuosly known bound for some vertex Folkman numbers.

I. Birindelli, E. Valdinoci

We consider a functional related with phase transition models in the Heisenberg group framework. We prove that level sets of local minimizers satisfy some density estimates, that is, they behave as "codimension one" sets. We thus deduce a uniform convergence property of these level sets to interfaces with minimal area. These results are then applied

Andrzej Matras'

J. Andre constructed a skewaffine structure as a group space of a normally transitive group. In the paper this construction was used to describe such an external structure associated with a point of Laguerre plane. Necessary conditions for ensure that the external structure is a skewaffine plane are given.

Ronaldo Garcia, Jorge Sotomayor

In this paper is studied the behavior of lines of curvature near umbilic points that appear generically on surfaces depending on two parameters.

Shiro Goto, Yukihide Takayama

We introduce a class of Stanley-Reisner ideals called generalized complete intersection, which is characterized by the property that all the residue class rings of powers of the ideal have FLC. We also give a combinatorial characterization of such ideals.

I. Kopshaev

The families of morphisms of vector fibre bundle (\cite{Mill1}) defined by the linear Hamiltonian systems of differential equations is considered. Authors proved that the specified families of morphisms is not saturated (\cite{Mill2}).

Loïc Chaumont, Víctor Manuel Rivero

A path decomposition at the infimum for positive self-similar Markov processes (pssMp) is obtained. Next, several aspects of the conditioning to hit 0 of a pssMp are studied. Associated to a given a pssMp $X,$ that never hits 0, we construct a pssMp $X^{\downarrow}$ that hits 0 in a finite time. The latter can be viewed as $X$ conditioned to hit 0 in a finit

I. Kopshaev, A. Sultanbekova

The families of morphisms of vector fibre bundle (\cite{Mill1}) defined by the linear systems of differential equations with non-negative coefficients is considered. Authors proved that the specified families of morphisms is not saturated (\cite{Mill2}).

Steffen Dereich, Thomas Mueller-Gronbach, Klaus Ritter

We study numerical integration of Lipschitz functionals on a Banach space by means of deterministic and randomized (Monte Carlo) algorithms. This quadrature problem is shown to be closely related to the problem of quantization of the underlying probability measure. In addition to the general setting we analyze in particular integration w.r.t. Gaussian measur

Regis Monneau, G. S. Weiss

We derive the precise limit of SHS in the high activation energy scaling suggested by B.J. Matkowksy-G.I. Sivashinsky in 1978 and by A. Bayliss-B.J. Matkowksy-A.P. Aldushin in 2002. In the time-increasing case the limit turns out to be the Stefan problem for supercooled water with spatially inhomogeneous coefficients. Although the present paper leaves open m

Taras Radul

We prove that a transfinite extension of asymptotic dimension asind is trivial. We introduce a transfinite extension of asymptotic dimension asdim and give an example of metric proper space which has transfinite infinite dimension.

K. Grove, B. Wilking, W. Ziller

We give an exhaustive description of all simply connected odd dimensional cohomogeneity one manifolds that can possibly support an invariant metric with positive sectional curvature. Among the known examples of odd dimensional manifolds with positive curvature, apart from spheres, there are two infinite families among the 7-dimensional Eschenburg spaces and

Florin Ambro

We describe the set of minimal log discrepancies of toric log varities, and study its accumulation points.

Grigori Litvinov

This paper is a very brief introduction to idempotent mathematics and related topics.

Leslie Saper

Let X be a locally symmetric space associated to a reductive algebraic group G defined over Q. L-modules are a combinatorial analogue of constructible sheaves on the reductive Borel-Serre compactification of X; they were introduced in [math.RT/0112251]. That paper also introduced the micro-support of an L-module, a combinatorial invariant that to a great ext

Liviu Ornea

I present a selection of results on locally conformally Kähler geometry published after 1997. The proofs are mainly sketched, some of them are even omitted. Several open problems are indicated in the end.

Marek Bozejko, Wlodzimierz Bryc

The free Meixner laws arise as the distributions of orthogonal polynomials with constant-coefficient recursions. We show that these are the laws of the free pairs of random variables which have linear regressions and quadratic conditional variances when conditioned with respect to their sum. We apply this result to describe free Levy processes with quadratic

Eli Glasner

A dynamical version of the Bourgain-Fremlin-Talagrand dichotomy shows that the enveloping semigroup of a dynamical system is either very large and contains a topological copy of the Stone-Cech compactification of the natural numbers, or it is a "tame" topological space whose topology is determined by the convergence of sequences. In the latter case w

Eli Glasner, Michael Megrelishvili

For an arbitrary topological group G any compact G-dynamical system (G,X) can be linearly G-represented as a weak*-compact subset of a dual Banach space V*. As was shown by Megrelishvili (2003), the Banach space V can be chosen to be reflexive iff the metric system (G,X) is weakly almost periodic (WAP). In this paper we study the wider class of compact G-sys

V. A. Fateev, V. V. Postnikov, Y. P. Pugai

We study the space of scaling fields in the $Z_N$ symmetric models with the factorized scattering and propose simplest algebraic relations between form factors induced by the action of deformed parafermionic currents. The construction gives a new free field representation for form factors of perturbed Virasoro algebra primary fields, which are parafermionic

Massimo Bianchi, Fabio Riccioni

We review recent progress towards the understanding of higher spin gauge symmetry breaking in AdS space from a holographic vantage point. According to the AdS/CFT correspondence, N=4 SYM theory at vanishing coupling constant should be dual to a theory in AdS which exhibits higher spin gauge symmetry enhancement. When the SYM coupling is non-zero, all but a h

Paolo Di Vecchia, Antonella Liccardo, Raffaele Marotta, Franco Pezzella

We construct the boundary state describing magnetized D9 branes in R^{3,1} x T^6 and we use it to compute the annulus and Moebius amplitudes. We derive from them, by using open/closed string duality, the number of Landau levels on the torus T^d.

S. Randjbar-Daemi, A. Salvio, M. Shaposhnikov

In this paper we examine the 4-dimensional effective theory for the light Kaluza-Klein (KK) modes. Our main interest is in the interaction terms. We point out that the contribution of the heavy KK modes is generally needed in order to reproduce the correct predictions for the observable quantities involving the light modes. As an example we study in some det

Andrew Hodges

We give a new formalism for pure gauge-theoretic scattering at tree-amplitude level. We first describe a generalization of the Britto-Cachazo-Feng recursion relation in which a significant restriction is removed. We then use twistor diagrams to express all tree amplitudes in a form independent of helicity. A formal procedure involving anticommuting elements

R. Rosenfelder

The worldline variational approach is extended beyond the quenched approximation, i.e. to include virtual pair production of heavy particles. This is achieved either by an expansion of the functional determinant to second order or by an hybrid ansatz for the quadratic trial action consisting of fields for the light particles and worldlines for the heavy ones

M. Hirai, S. Kumano, N. Saito

We report global analysis results for polarized parton distribution functions in the nucleon. The optimum distributions are determined by using spin asymmetry data on polarized lepton scattering on proton, neutron, and deuteron. Their uncertainties are estimated by the Hessian method. As a result, polarized quark distributions are relatively well determined,

Patricia Ball, Roman Zwicky

We derive constraints on the asymmetry a1 of the momentum fractions carried by quark and antiquark in K and K* mesons in leading twist. These constraints follow from exact operator identities and relate a1 to SU(3) breaking quark-antiquark-gluon matrix elements which we determine from QCD sum rules. Comparing our results to determinations of a1 from QCD sum

A. Denner, S. Dittmaier

We briefly sketch the methods for a numerically stable evaluation of tensor one-loop integrals that have been used in the calculation of the complete electroweak one-loop corrections to $\Pep\Pem\to4 $fermions. In particular, the improvement of the new methods over the conventional Passarino--Veltman reduction is illustrated for some 4-point integrals in the

Naohiro Muta, Nobuhiro Uekusa

We study linearized graviton in the presence of a four-dimensional cosmological constant in two brane models with a warped extra dimension. In explicit models including bulk scalar fields, we calculate the masses of Kaluza-Klein modes of graviton and their interactions with matter on the visible brane. It is shown that the effects of the cosmological constan

J. Balog, F. Niedermayer, P. Weisz

In a recent paper Stevenson claimed that analysis of the data on the wave function renormalization constant near the critical point of the 4d Ising model is not consistent with analytical expectations. Here we present data with improved statistics and show that the results are indeed consistent with conventional wisdom once one takes into account the uncerta

S. Balestra, S. Cecchini, G. Giacomelli, R. Giacomelli

The strange quark matter (SQM) may be the ground state of QCD; nuggets of SQM could be present in cosmic rays (CR). SLIM is a large area experiment, using CR39 and Makrofol track etch detectors, presently deployed at the high altitude CR Laboratory of Chacaltaya, Bolivia. We discuss the expected properties of SQM, from the point of view of its search with SL

A. W. Beckwith

We previously showed that we can use di quark pairs as a model of how nucleation of a new universe occurs. We now can construct a model showing evolution from a dark matter dark energy mix to a pure cosmological constant cosmology due to changes in the slope of the resulting scalar field,using much of Scherrer's k-essence model.This same construction per

David Mattingly

Questions about black holes in quantum gravity generally presuppose the presence of a horizon. Recently Carlip has shown that enforcing an initial data surface to be a horizon leads to the correct form for the Bekenstein-Hawking entropy of the black hole. Requiring a horizon also constitutes fixed background geometry, which generically leads to non-conservat

A. Sandoval-Villalbazo, A. L. Garcia-Perciante, L. S. Garcia-Colin

This paper shows that a hyperbolic equation for heat conduction can be obtained directly using the tenets of linear irreversible thermodynamics in the context of the five dimensional space-time metric originally proposed by T. Kaluza back in 1922. The associated speed of propagation is slightly lower than the speed of light by a factor inversely proportional

Oren Kurland, Lillian Lee, Carmel Domshlak

We present a novel approach to pseudo-feedback-based ad hoc retrieval that uses language models induced from both documents and clusters. First, we treat the pseudo-feedback documents produced in response to the original query as a set of pseudo-queries that themselves can serve as input to the retrieval process. Observing that the documents returned in resp

Oren Kurland, Lillian Lee

Inspired by the PageRank and HITS (hubs and authorities) algorithms for Web search, we propose a structural re-ranking approach to ad hoc information retrieval: we reorder the documents in an initially retrieved set by exploiting asymmetric relationships between them. Specifically, we consider generation links, which indicate that the language model induced

Christian Gagné, Marc Schoenauer, Marc Parizeau, Marco Tomassini

Fitness functions based on test cases are very common in Genetic Programming (GP). This process can be assimilated to a learning task, with the inference of models from a limited number of samples. This paper is an investigation on two methods to improve generalization in GP-based learning: 1) the selection of the best-of-run individuals using a three data s

Petrus H. Potgieter

This paper reviews the Church-Turing Thesis (or rather, theses) with reference to their origin and application and considers some models of "hypercomputation", concentrating on perhaps the most straight-forward option: Zeno machines (Turing machines with accelerating clock). The halting problem is briefly discussed in a general context and the sugges

J. J. Rehr, J. J. Kas, M. P. Prange, F. D. Vila

Ab initio approaches are introduced for calculations of inelastic losses and vibrational damping in core level x-ray and electron spectroscopies. From the dielectric response function we obtain system-dependent self-energies, inelastic mean free paths, and losses due to multiple-electron excitations, while from the dynamical matrix we obtain phonon spectra a

Shai Carmi, Shlomo Havlin, Scott Kirkpatrick, Yuval Shavitt

The k-shell decomposition of a random graph provides a different and more insightful separation of the roles of the different nodes in such a graph than does the usual analysis in terms of node degrees. We develop this approach in order to analyze the Internet's structure at a coarse level, that of the "Autonomous Systems" or ASes, the subnetwork

Alberto Rosso, Edmond Orignac, R. Chitra, Thierry Giamarchi

When unscreened charged impurities are introduced in charge density wave system the long wavelength component of the disorder is long ranged and dominates static correlation functions. We calculate the x-ray intensity and find that it is identical to the one produced by thermal fluctuations in a disorder-free smectic-A. We suggest that this effect could be o

L. I. Salminen, J. M. Pulakka, J. Rosti, M. J. Alava

Acoustic emission or crackling noise is measured from an experiment on splitting or peeling of paper. The energy of the events follows a power-law, with an exponent $β\sim 1.8\pm 0.2$. The event intervals have a wide range, but superposed on scale-free statistics there is a time-scale, related to the typical spatial scale of the microstructure (a bond betwee

Nicholas Bailey, Thierry Cretegny, James P. Sethna, Valerie R. Coffman

The complexities of today's materials simulations demand computer codes which are both powerful and highly flexible. A researcher should be able to readily choose different geometries, different materials and different algorithms without having to write low-level code and recompile each time. We describe a molecular dynamics (MD) code, called Digital Mat

Sorin Bastea

A Comment on the Letter by D. Hemanth Kumar et al., Phys. Rev. Lett. 93, 144301 (2004)

F. Szalma, D. B. Dougherty, M. Degawa, Ellen D. Williams

We analyze correlations in step-edge fluctuations using the Bortz-Kalos-Lebowitz kinetic Monte Carlo algorithm, with a 2-parameter expression for energy barriers, and compare with our VT-STM line-scan experiments on spiral steps on Pb(111). The scaling of the correlation times gives a dynamic exponent confirming the expected step-edge-diffusion rate-limiting

E. H. Hwang, S. Das Sarma

Recent measurements of the 2D Hall resistance show that the Hall coefficient is independent of the applied in-plane magnetic field, i.e., the spin-polarization of the system. We calculate the weak-field Hall coefficient and the magnetoresistance of a spin polarized 2D system using the semi-classical transport approach based on the screening theory. We solve

Frank Krüger, Stefan Scheidl

Recently it was argued that quantum phase transitions can be radically different from classical phase transitions with as a highlight the 'deconfined critical points' exhibiting fractionalization of quantum numbers due to Berry phase effects. Such transitions are supposed to occur in frustrated ('$J_1$-$J_2$') quantum magnets. We have develop

V. Alfi, F. Coccetti, M. Marotta, A. Petri

We consider the role of finite size effects on the value of the effective Hurst exponent H. This problem is motivated by the properties of the high frequency daily stock-prices. For a finite size random walk we derive some exact results based on Spitzer's identity. The conclusion is that finite size effects strongly enhance the value of H and the converg

Anand Bala Subramaniam, Manouk Abkarian, Howard A. Stone

Assembly of colloidal particles on fluid interfaces is a promising technique for synthesizing two-dimensional micro-crystalline materials useful in fields as diverse as biomedicine1, materials science2, mineral flotation3 and food processing4. Current approaches rely on bulk emulsification methods, require further chemical and thermal treatments, and are res

Fernando M. Cucchietti, Eddy Timmermans

A neutral impurity atom immersed in a dilute Bose-Einstein condensate (BEC) can have a bound ground state in which the impurity is self-localized. In this small polaron-like state, the impurity distorts the density of the surrounding BEC, thereby creating the self-trapping potential minimum. We describe the self-localization in a strong coupling approach.

Hirofumi Morise, Shiho Nakamura

A new way of magnetization switching employing both the spin-transfer torque and the torque by a magnetic field is proposed. The solution of the Landau-Lifshitz-Gilbert equation shows that the dynamics of the magnetization in the initial stage of the switching is similar to that in the precessional switching, while that in the final stage is rather similar t

Ram Prakash, S. Amirthapandian, D. M. Phase, S. K. Deshpande

The effects of ion beam induced atomic mixing and subsequent thermal treatment in Si/C multilayer structures are investigated by use of the technique of grazing incidence X-ray diffraction (GIXRD) and Raman spectroscopy. The [Si (3.0 nm) / C (2.5 nm)]x10 /Si multilayer films were prepared by electron beam evaporation under ultra high vacuum (UHV) environment

Yanwei Ma, Xianping Zhang, G. Nishijima, K. Watanabe

Nanocarbon-doped Fe-sheathed MgB2 tapes with different doping levels were prepared by the in situ powder-in-tube method. Compared to the undoped tapes, Jc for all the C-doped samples was enhanced by more than an order of magnitude in magnetic fields above 9 T. At 4.2 K, the transport Jc for the 5 at% doped tapes reached 1.85x104 A/cm2 at 10 T and 2.8x103 A/c

A. Abendschein, F. F. Assaad

We study the temperature dependence of the single particle spectral function as well as of the dynamical spin and charge structure factors for the one-dimensional Hubbard model using the finite temperature auxiliary field quantum Monte Carlo algorithm. The parameters of our simulations are chosen so to at best describe the low temperature photoemission spect

A. V. Gorbach, S. Denisov, S. Flach

We study the energy flow due to the motion of topological solitons in nonlinear extended systems in the presence of damping and driving. The total field momentum contribution to the energy flux, which reduces the soliton motion to that of a point particle, is insufficient. We identify an additional exchange energy flux channel mediated by the spatial and tem

Igor Goychuk

Rate processes with dynamical disorder are investigated within a simple framework provided by unidirectional electron transfer (ET) with fluctuating transfer rate. The rate fluctuations are assumed to be described by a non-Markovian stochastic jump process which reflects conformational dynamics of an electron transferring donor-acceptor molecular complex. A

Igor Goychuk, Peter Hanggi

We consider the problem of stochastic averaging of a quantum two-state dynamics driven by non-Markovian, discrete noises of the continuous time random walk type (multistate renewal processes). The emphasis is put on the proper averaging over the stationary noise realizations corresponding, e.g., to a stationary environment. A two state non-Markovian process

E. Ehrenfreund, C. C. Wu, Z. V. Vardeny

The emission spectra of many pi-conjugated polymers and oligomers contain side-band replicas with apparent frequencies that do not match the Raman active mode frequencies. Using a time dependent model we show that in such many mode systems, the increased damping of the time dependent transition dipole moment correlation function results in an effective elimi

Hidetsugu Sakaguchi, Boris A. Malomed

We introduce a dynamical model of a Bose-Einstein condensate based on the 2D Gross-Pitaevskii equation, in which the nonlinear coefficient is a function of radius. The model describes a situation with spatial modulation of the negative atomic scattering length, via the Feshbach resonance controlled by a properly shaped magnetic of optical field. We focus on

H. Iwasawa, K. Yamakawa, T. Saitoh, J. Inaba

We present the electronic structure of Sr_{1-(x+y)}La_{x+y}Ti_{1-x}Cr_{x}O_{3} investigated by high-resolution photoemission spectroscopy. In the vicinity of Fermi level, it was found that the electronic structure were composed of a Cr 3d local state with the t_{2g}^{3} configuration and a Ti 3d itinerant state. The energy levels of these Cr and Ti 3d states

Nikolay T. Bagraev, Wolfgang Gehlhoff, Leonid E. Klyachkin, Anna M. Malyarenko

We present the findings of the superconductivity in the silicon nanostructures prepared by short time diffusion of boron of the n - type Si (100) surface. These Si - based nanostructures represent the p - type ultra-narrow self - assembled silicon quantum wells confined by the delta - barriers heavily with boron. The resistivity, thermo - emf and magnetic su

Sungjun Kim, Kunal K. Das, Ari Mizel

We present a prescription for generating pure spin current or spin selective current, based on adiabatic quantum pumping in a tight-binding model of a one dimensional conductor. A formula for the instantaneous pumped current is derived without introducing the scattering matrix. Our calculations indicate that some pumping cycles produce the maximum value 2 of

Marina Bastea, Sorin Bastea, James A. Emig, Paul T. Springer

We observed dynamically driven phase transitions in isentropically compressed bismuth. By changing the stress loading conditions we explored two distinct cases: one in which the experimental signature of the phase transformation corresponds to phase-boundary crossings initiated at both sample interfaces, and another in which the experimental trace is due to

T. Masseron, B. Plez, F. Primas, S. Van Eck

Large surveys of very metal-poor stars have revealed in recent years that a large fraction of these objects were carbon-rich, analogous to the more metal-rich CH-stars. The abundance peculiarities of CH-stars are commonly explained by mass-transfer from a more evolved companion. In an effort to better understand the origin and importance for Galactic evoluti

E. Le Floc'h, V. Charmandaris, W. J. Forrest, F. Mirabel

We report on the first mid-infrared observations of 16 GRB host galaxies performed with the Spitzer Space Telescope, and investigate the presence of evolved stellar populations and dust-enshrouded star-forming activity associated with GRBs. Only a very small fraction of our sample is detected by Spitzer, which is not consistent with recent works suggesting t

E. Le Floc'h, V. Charmandaris, W. J. Forrest, F. Mirabel

We report on IRAC-4.5mic, IRAC-8.0mic and MIPS-24mic deep observations of 16 Gamma-Ray Burst (GRBs) host galaxies performed with the Spitzer Space Telescope, and we investigate in the thermal infrared the presence of evolved stellar populations and dust-enshrouded star-forming activity associated with these objects. Our sample is derived from GRBs that were