March 2006 arXiv papers — page 38

Michel Brion

We study the cone of effective divisors and the total coordinate ring of wonderful varieties, with applications to their automorphism group. We show that the total coordinate ring of any spherical variety is obtained from that of the associated wonderful variety by a base change of invariant subrings.

Ghislain Jaudon, Hugo Parlier

We solve the problem of finding a sharp upper bound on the minimum angle formed by $N$ points in the Euclidean and Hyperbolic planes.

Michel Fliess, Cédric Join, Mamadou Mboup, Hebertt Sira-Ramirez

A control strategy without any precise mathematical model is derived for linear or nonlinear systems which are assumed to be finite-dimensional. Two convincing numerical simulations are provided.

The BABAR Collaboration, B. Aubert

We describe searches for decays to two-body charmless final states eta' eta, eta' pi0 and eta pi0 of B0 mesons produced in e+e- annihilation. The data, collected with the BaBar detector at the Stanford Linear Accelerator Center, represent 232 million produced B-anti-B pairs. The results for branching fractions are, in units of 10^-6 (upper limits at

Shiping Feng, Tianxing Ma

Within the t-t'-J model, the physical properties of doped cuprates in the superconducting-state are discussed based on the kinetic energy driven superconducting mechanism. We show that the superconducting-state in cuprate superconductors is controlled by both superconducting gap parameter and single particle coherence, and then quantitatively reproduce s

Alexey V. Gavrilov

We consider the known functional identity on the Weierstrass sigma function. A complete classification of odd entire functions which satisfy the same identity is obtained.

Dan Abramovich, Tom Graber, Angelo Vistoli

Long ago, in math.AG/0112004, we pledged more details on the algebraic version of Chen-Ruan's math.AG/0103156. This is it.

Philip C. Argyres, Anton Kapustin, Nathan Seiberg

We point out that for N=4 gauge theories with exceptional gauge groups G_2 and F_4 the S-duality transformation acts on the moduli space by a nontrivial involution. We note that the duality groups of these theories are the Hecke groups with elliptic elements of order six and four, respectively. These groups extend certain subgroups of SL(2,Z) by elements wit

Rafael G. Campos, Eduardo S. Tututi

We study the Schwinger model on a lattice consisting of zeros of the Hermite polynomials that incorporates a lattice derivative and a discrete Fourier transform with many properties. Such a lattice produces a Klein-Gordon equation for the boson field and the exact value of the mass in the asymptotic limit if the boundaries are not taken into account. On the

S. Eh. Shirmovsky

In Liouville formalism the expression for density matrix, determining the time evolution of unstable $π^{\pm}$ - meson in the framework of unified formulation of quantum and kinetic dynamics is defined. The eigenvalues problem is investigated in the framework of Prigogine's principles of description of nonequilibrium processes at microscopic level. The p

Domenico D'Alessandro, Raffaele Romano

We describe a decomposition of the Lie group of unitary evolutions for a bipartite quantum system of arbitrary dimensions. The decomposition is based on a recursive procedure which systematically uses the Cartan classification of the symmetric spaces of the Lie group SO(n). The resulting factorization of unitary evolutions clearly displays the local and enta

J. Batle, A. R. Plastino, M. Casas, A. Plastino

It has been recently pointed out by Caves, Fuchs, and Rungta that real quantum mechanics (that is, quantum mechanics defined over real vector spaces provides an interesting foil theory whose study may shed some light on just which particular aspects of quantum entanglement are unique to standard quantum theory, and which ones are more generic over other phys

J. Batle, M. Casas, A. Plastino, A. R. Plastino

Quantum gates, that play a fundamental role in quantum computation and other quantum information processes, are unitary evolution operators $\hat U$ that act on a composite system changing its entanglement. In the present contribution we study some aspects of these entanglement changes. By recourse of a Monte Carlo procedure, we compute the so called "en

J. Batle, A. R. Plastino, M. Casas, A. Plastino

We consider the change of entanglement of formation $ΔE$ produced by a unitary transformation acting on a general (pure or mixed) state $ρ$ describing a system of two qubits. We study numerically the probabilities of obtaining different values of $ΔE$, assuming that the initial state is randomly distributed in the space of all states according to the product

J. Batle, M. Casas, A. Plastino, A. R. Plastino

The maximally entangled mixed states of Munro, James, White, and Kwiat [Phys. Rev. A {\bf 64} (2001) 030302] are shown to exhibit interesting features vis a vis conditional entropic measures. The same happens with the Ishizaka and Hiroshima states [Phys. Rev. A {\bf 62} 022310 (2000)], whose entanglement-degree can not be increased by acting on them with log

J. Batle, M. Casas, A. Plastino, A. R. Plastino

We ascertain, following ideas of Arnesen, Bose, and Vedral concerning thermal entanglement [Phys. Rev. Lett. {\bf 87} (2001) 017901] and using the statistical tool called {\it entropic non-triviality} [Lamberti, Martin, Plastino, and Rosso, Physica A {\bf 334} (2004) 119], that there is a one to one correspondence between (i) the mixing coefficient $x$ of a

Hoshang Heydari

The best upper bound for the violation of the Clauser-Horne-Shimony-Holt (CHSH) inequality was first derived by Tsirelson. For increasing number of $\pm 1$ valued observables on both sites of the correlation experiment, Tsirelson obtained the Grothendieck's constant ($\mathcal{K}_{G}\approx 1.73\pm0.06$) as a limit for the maximal violation. In this pape

G. B. Furman, S. D. Goren, J. -S. Lee, A. K. Khitrin

Stimulated wave of polarization, triggered by a flip of a single spin, presents a simple model of quantum amplification. Previously, it has been found that such wave can be excited in a 1D Ising chain with nearest-neighbor interactions, irradiated by a weak resonant transverse field. Here we explore models with more realistic Hamiltonians, in particular, wit

Carlos Escudero

Strong experimental evidence has indicated that tumor growth belongs to the molecular beam epitaxy universality class. This type of growth is characterized by the constraint of cell proliferation to the tumor border, and surface diffusion of cells at the growing edge. Tumor growth is thus conceived as a competition for space between the tumor and the host, a

Andrea Alu, Nader Engheta

Following our recent theoretical development of the concept of nano-inductors, nano-capacitors and nano-resistors at optical frequencies and the possibility of synthesizing more complex nano-scale circuits, here we theoretically investigate in detail the problem of optical nano-transmission-lines (NTL) that can be envisioned by properly joining together arra

Andrea Alu, Nader Engheta, Richard W. Ziolkowski

Pairing together material slabs with opposite signs for the real parts of their constitutive parameters has been shown to lead to interesting and unconventional properties that are not otherwise observable for single slabs. One such case was demonstrated analytically for the conjugate (i.e., complementary) pairing of infinite planar slabs of epsilon-negative

Michael L. Gorodetsky, Aleksey E. Fomin

Quasiclassical approach and geometric optics allow to describe rather accurately whispering gallery modes in convex axisymmetric bodies. Using this approach we obtain practical formulas for the calculation of eigenfrequencies and radiative Q-factors in dielectrical spheroid and compare them with the known solutions for the particular cases and with numerical

Simon F. Tolic-Norrelykke, Mette B. Rasmusssen, Francesco S. Pavone, Kirstine Berg-Sorensen

The TATA-box Binding Protein (TBP) is required by all three eukaryotic RNA polymerases for the initiation of transcription from most promoters. TBP recognizes, binds to, and bends promoter sequences called ``TATA-boxes'' in the DNA. We present results from the study of individual Saccharomyces cerevisia TBPs interacting with single DNA molecules cont

N. J. Sircombe, M. E. Dieckmann, P. K. Shukla, T. D. Arber

We investigate the acceleration of electrons via their interaction with electrostatic waves, driven by the relativistic Buneman instability, in a system dominated by counter-propagating proton beams. We observe the growth of these waves and their subsequent saturation via electron trapping for a range of proton beam velocities, from 0.15c to 0.9c. We can rep

M. S. de la Lama, I. G. Szendro, J. R. Iglesias, H. S. Wio

We analyze a simple opinion formation model consisting of two parties, A and B, and a group I, of undecided agents. We assume that the supporters of parties A and B do not interact among them, but only interact through the group I, and that there is a nonzero probability of a spontaneous change of opinion (A->I, B->I). From the master equation, and via van K

P. Pant, P. Hegde, U. C. Dumka, Ram Sagar

Collocated measurements of the mass concentrations of aerosol black carbon (BC) and composite aerosols near the surface were carried out along with spectral aerosol optical depths (AODs) from a high altitude station, Manora Peak in Central Himalayas, during a comprehensive aerosol field campaign in December 2004. Despite being a pristine location in the Shiv

Basarab Nicolescu

We first analyze the transdisciplinary model of Reality and its key-concept of "Levels of Reality". We then compare this model with the one elaborated by Werner Heisenberg in 1942.

V. Hnizdo

The second-order partial derivatives of the Coulomb potential of a point charge can be regularized using the Coulomb potential of a charge of the oblate spheroidal shape that a moving rest-frame-spherical charge acquires by the Lorentz contraction. This `physical' regularization is shown to be fully equivalent to the standard delta-function identity invo

Serban Misicu

The properties of the Isoscalar Giant Dipole Resonance (ISGDR) and its electromagnetic structure are investigated within a semiclassical nuclear Fermi-Fluid dynamical approach. Microscopical calculations pointing to a ISGDR distribution splitted into two main broad structures is confirmed within the presented macroscopic approach by the occurence of a '&

J. Rotureau, N. Michel, W. Nazarewicz, M. Ploszajczak

The density matrix renormalization group (DMRG) approach is extended to complex-symmetric density matrices characteristic of many-body open quantum systems. Within the continuum shell model, we investigate the interplay between many-body configuration interaction and coupling to open channels. It is shown that the DMRG technique applied to broad resonances i

C. Downum, T. Barnes, J. R. Stone, E. S. Swanson

We demonstrate the calculation of the coupling constants and form factors required by effective hadron lagrangians using the quark model. These relations follow from equating expressions for strong transition amplitudes in the two approaches. As examples we derive the NNm nucleon-meson coupling constants and form factors for m = pi, eta, eta', sigma, a_0

S. E. A. Orrigo, H. Lenske, F. Cappuzzello, A. Cunsolo

Fano-resonances are investigated as a new continuum excitation mode in exotic nuclei. By theoretical model calculations we show that the coupling of a single particle elastic channel to closed core-excited channels leads to sharp resonances in the low-energy continuum. A signature for such bound states embedded in the continuum (BSEC) are characteristic inte

J. Wang, T. Keutgen, R. Wada, K. Hagel

The sizes, temperatures and free neutron to proton ratios of the initial interaction zones produced in the collisions of 40 MeV/nucleon $^{40}$Ar + $^{112}$Sn and 55 MeV/nucleon$^{27}$Al + $^{124}$Sn are derived using total detected neutron plus charged particle multiplicity as a measure of the impact parameter range and number of participant nucleons. The s

Jana Bielcikova

We present results on two-particle azimuthal correlations of high-$p_T$ neutral strange baryons ($Λ$,$\barΛ$) and mesons ($K^0_S$) associated with non-identified charged particles in d+Au and Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV. In particular, we discuss properties of the near-side yield of associated charged particles as a function of centrality,

S. Skupin, O. Bang, D. Edmundson, W. Krolikowski

We discuss existence and stability of two-dimensional solitons in media with spatially nonlocal nonlinear response. We show that such systems, which include thermal nonlinearity and dipolar Bose Einstein condensates, may support a variety of stationary localized structures - including rotating spatial solitons. We also demonstrate that the stability of these

M. Mantoiu, S. Richard, R. Tiedra de Aldecoa

We put into evidence graphs with adjacency operator whose singular subspace is prescribed by the kernel of an auxiliary operator. In particular, for a family of graphs called admissible, the singular continuous spectrum is absent and there is at most an eigenvalue located at the origin. Among other examples, the one-dimensional XY model of solid-state physic

Søren Fournais, Maria Hoffmann-Ostenhof, Thomas Hoffmann-Ostenhof, Thomas Østergaard Sørensen

We investigate regularity properties of molecular one-electron densities rho near the nuclei. In particular we derive a representation rho(x)=mu(x)*(e^F(x)) with an explicit function F, only depending on the nuclear charges and the positions of the nuclei, such that mu belongs to C^{1,1}(R^3), i.e., mu has locally essentially bounded second derivatives. An e

M. Gubinelli

In this note we study a class of specifications over $d$-dimensional Wiener measure which are invariant under uniform translation of the paths. This degeneracy is removed by restricting the measure to the $σ$-algebra generated by the increments of the coordinate process. We address the problem of existence and uniqueness of Gibbs measures and prove a central

A. Aiello, J. P. Woerdman

We give a self-contained exposition of some mathematical aspects of the Mueller-Stokes formalism. In the first part we review some basic notions of linear algebra and establish a proper notation. In the second part we introduce the Mueller-Stokes formalism and derive some useful mathematical relation between physical quantities. Finally a useful decompositio

P. Di Francesco, P. Zinn-Justin

We prove that the sum of entries of the suitably normalized groundstate vector of the O(1) loop model with periodic boundary conditions on a periodic strip of size 2n is equal to the total number of n x n alternating sign matrices. This is done by identifying the state sum of a multi-parameter inhomogeneous version of the O(1) model with the partition functi

Jack Xin, Yingyong Qi

A many to one discrete auditory transform is presented to map a sound signal to a perceptually meaningful spectrum on the scale of human auditory filter band widths (critical bands). A generalized inverse is constructed in closed analytical form, preserving the band energy and band signal to noise ratio of the input sound signal. The forward and inverse tran

Robert Lipton

A multi-scale characterization of the field concentrations inside composite and polycrystalline media is developed. The analysis focuses on gradient fields associated with the intensive quantities given by the temperature and the electric potential. In the linear regime these quantities are modeled by the solution of a second order elliptic partial different

Shuangquan Wang, Ali Abdi

Let $\mathbf{H}=(h_{ij})$ and $\mathbf{G}=(g_{ij})$ be two $m\times n$, $m\leq n$, random matrices, each with i.i.d complex zero-mean unit-variance Gaussian entries, with correlation between any two elements given by $\mathbb{E}[h_{ij}g_{pq}^\star]=ρδ_{ip}δ_{jq}$ such that $|ρ|<1$, where ${}^\star$ denotes the complex conjugate and $δ_{ij}$ is the Kronecker

Ionut Chifan, Gabriel Picioroaga

In this paper we study the non-amenability question of the Thompson group $F$ from the $C^{*}$ algebra side. Using a characterization of amenability in this framework we set about evaluating the reduced norm of the averages $\frac{1}{n}\sum x_0^ix_1x_0^{-i}$, where $x_0$ and $x_1$ are the generators of $F$ in its finite presentation. We prove that when $n$ i

Sebastian Klein

In this article, relations between the root space decomposition of a Riemannian symmetric space of compact type and the root space decompositions of its totally geodesic submanifolds (symmetric subspaces) are described. These relations provide an approach to the classification of totally geodesic submanifolds in Riemannian symmetric spaces. In this way a cla

Vik. S. Kulikov

A complete description of the Alexander modules of knotted $n$-manifolds in the sphere $S^{n+2}$, $n\geq 2$, and irreducible Hurwitz curves is given. This description is applied to investigate properties of the first homology groups of cyclic coverings of the sphere $S^{n+2}$ and the projective complex plane $\mathbb C\mathbb P^2$ branched respectively alone

Marco Fontana, K. Alan Loper

An historical overview of Kronecker function rings, Nagata rings, and related star and semistar operations

Laurent Mazet

In this paper, we study the Dirichlet problem associated to the maximal surface equation. We prove the uniqueness of bounded solutions to this problem in unbounded domain in R^2.

David Marquez-Carreras, Carles Rovira, Samy Tindel

This note is concerned with a diluted version of the perceptron model. We establish a replica symmetric formula at high temperature, which is achieved by studying the asymptotic behavior of a given spin magnetization. Our main task will be to identify the order parameter of the system.

Thierry De La Rue

V.A. Rohlin asked in 1949 whether 2-fold mixing implies 3-fold mixing for a stationary process indexed by Z, and the question remains open today. In 1978, F. Ledrappier exhibited a counterexample to the 2-fold mixing implies 3-fold mixing problem, the so-called &#34;3-dot system&#34;, but in the context of stationary random fields indexed by ZxZ. In this wor

Christophe Besse, Rémi Carles, Norbert Mauser, Hans-Peter Stimming

We consider the focusing nonlinear Schrödinger equation, in the $L^2$-critical and supercritical cases. We investigate numerically the dependence of the blow-up time on a parameter in three cases: dependence upon the coupling constant, when the initial data are fixed; dependence upon the strength of a quadratic oscillation in the initial data when the equati

Joseph Gubeladze

For a regular ring R and an affine monoid M the homotheties of M act nilpotently on the Milnor unstable groups of R[M]. This strengthens the K_2 part of the main result of [G5] in two ways: the coefficient field of characteristic 0 is extended to any regular ring and the stable K_2-group is substituted by the unstable ones. The proof is based on a polyhedral

Alexander Premet, Helmut Strade

We give a comprehensive survey of the theory of finite dimensional Lie algebras over an algebraically closed field of characteristic p>0 and announce that for p>3 the classification of finite dimensional simple Lie algebras is complete. Any such Lie algebra is up to isomorphism either classical (i.e. comes from characteristic 0) or a filtered Lie algebra of

Alexander Barvinok

Given m positive integers R=(r_i), n positive integers C=(c_j) such that sum r_i = sum c_j =N, and mn non-negative weights W=(w_{ij}), we consider the total weight T=T(R, C; W) of non-negative integer matrices (contingency tables) D=(d_{ij}) with the row sums r_i, column sums c_j, and the weight of D equal to prod w_{ij}^{d_{ij}}. We present a randomized alg

Vesselin Drensky, Roberto La Scala

We introduce the notion of Groebner S-basis of an ideal of the free associative algebra K<X> over a field K invariant under the action of a semigroup S of endomorphisms of the algebra. We calculate the Groebner S-bases of the ideal corresponding to the universal enveloping algebra of the free nilpotent of class 2 Lie algebra and of the T-ideal generated by t

Kiyonori Gomi

We construct projective unitary representations of the smooth Deligne cohomology group of a compact oriented Riemannian manifold of dimension 4k+1, generalizing positive energy representations of the loop group of the circle. We also classify such representations under a certain condition. The number of the equivalence classes of irreducible representations

Sharon J. X. Hou, Jiang Zeng

In the present paper combinatorial identities involving q-dual sequences or polynomials with coefficients q-dual sequences are derived. Further, combinatorial identities for q-binomial coefficients(Gaussian coefficients), q-Stirling numbers and q-Bernoulli numbers and polynomials are deduced.

Razvan Veliche

The goal of these notes is to prove that the mapping class groups of a closed orientable surface of genus two, with punctures, are not Kähler

Donu Arapura

This is a sequel to the paper &#34;Frobenius amplitude and strong vanishing theorems for vector bundles&#34; (math.AG/0202129). We introduce a more elementary variant of the notion of F-amplitude from the earlier paper which we call amplitude. This provides another measure of positivity of a vector bundle which is related to a number of preexisting positivit

Oleg Lebedev, Hans Peter Nilles, Michael Ratz

Consistent uplifting of AdS vacua in string theory often requires extra light degrees of freedom in addition to those of a (Kaehler) modulus. Here we consider the possibility that de Sitter and Minkowski vacua arise due to hidden sector matter interactions. We find that, in this scheme, the hierarchically small supersymmetry breaking scale can be explained b

Mithat Unsal

We examine the relation between twisted versions of the extended supersymmetric gauge theories and supersymmetric orbifold lattices. In particular, for the $\mathcal{N}=4$ SYM in $d=4$, we show that the continuum limit of orbifold lattice reproduces the twist introduced by Marcus, and the examples at lower dimensions are usually Blau-Thompson type. The orbif

Kenji Sakamoto

We construct new non-singular and time-dependent solutions from the black diholes with unbalanced magnetic charge. These solutions are constructed by the double Wick rotation with the analytic continuation of the mass or NUT-parameter of unbalanced black diholes. In the limit of balanced magnetic charge, our solutions reduce to the S-brane solution obtained

N. Ghahramany, M. Ghanaatian

The elementary reaction of kaon exclusive electroproduction on protons has been studied in a broad kinematical range. Data for the calculation of the form factor of the kaon have been taken at different values of the invariant center of mass energy W in the range W=1.8, 1.85, 1.98, 2.08 (GeV), for one value of the transferred 4-momentum Q2=2.35 (GeV/c)2. In

R. F. Wagenbrunn, T. Melde, W. Plessas

The relativistic constituent quark model of low-energy quantum chromodynamics is found to yield a consistent picture of the electroweak structure of the nucleons. Notably, the electromagnetic and axial form factors of both the proton and the neutron can be described in close agreement with existing experimental data in the domain of low to moderate momentum

H1 Collaboration

Differential dijet cross sections are measured in photoproduction in the region of photon virtualities Q^2 < 1 GeV^2 with the H1 detector at the HERA ep collider using an integrated luminosity of 66.6 pb^{-1}. Jets are defined with the inclusive k_T algorithm and a minimum transverse momentum of the leading jet of 25 GeV is required. Dijet cross sections are

BaBar Collaboration

We present measurements of the branching fraction and time-dependent CP asymmetries in B0 -> JPsi pi0 decays based on (231.8 +/- 2.6) x 10**6 asymmetries Y(4S) -> BBbar decays collected with the BaBar detector at the SLAC PEP-II asymmetric-energy B factory. We obtain a branching fraction B(B0 -> JPsi pi0) = (1.94 +/- 0.22 (stat.) +/- 0.17 (syst.)) x 10**-5.

Thomas Marlow

We compare and contrast the basic principles of two philosophies: Bayesianism and relationalism. These two philosophies are both based upon criteria of rationality. The analogy invoked in such a comparison seems rather apt when discussing tentative proofs of quantum nonlocality. We argue that Bayesianism is almost to quantum theory, what general covariance i

Hubert Bray, Sean Hayward, Marc Mars, Walter Simon

Motivated by the conjectured Penrose inequality and by the work of Hawking, Geroch, Huisken and Ilmanen in the null and the Riemannian case, we examine necessary conditions on flows of two-surfaces in spacetime under which the Hawking quasilocal mass is monotone. We focus on a subclass of such flows which we call uniformly expanding, which can be considered

Esther M. Arkin, Michael A. Bender, Joseph S. B. Mitchell, Valentin Polishchuk

We introduce the snowblower problem (SBP), a new optimization problem that is closely related to milling problems and to some material-handling problems. The objective in the SBP is to compute a short tour for the snowblower to follow to remove all the snow from a domain (driveway, sidewalk, etc.). When a snowblower passes over each region along the tour, it

Carl Lagoze, Dean Krafft, Tim Cornwell, Dean Eckstrom

The NSDL (National Science Digital Library) is funded by the National Science Foundation to advance science and match education. The inital product was a metadata-based digital library providing search and access to distributed resources. Our recent work recognizes the importance of context - relations, metadata, annotations - for the pedagogical value of a

Viktor Zhumatiy, Faustino Gomez, Marcus Hutter, Juergen Schmidhuber

We address the problem of autonomously learning controllers for vision-capable mobile robots. We extend McCallum&#39;s (1995) Nearest-Sequence Memory algorithm to allow for general metrics over state-action trajectories. We demonstrate the feasibility of our approach by successfully running our algorithm on a real mobile robot. The algorithm is novel and uni

Aldemar Torres, Rene van Roij, Gabriel Tellez

We extend the classical Gouy-Chapman model of two planar parallel interacting double-layers, which is used as a first approximation to describe the force between colloidal particles, by considering the finite-thickness of the colloids. The formation of two additional double layers due to this finite thickness, modifies the interaction force compared to the G

Christopher Jarzynski

Equilibrium free energy differences are given by exponential averages of nonequilibrium work values; such averages, however, often converge poorly, as they are dominated by rare realizations. I show that there is a simple and intuitively appealing description of these rare but dominant realizations. This description is expressed as a duality between ``forwar

D. S. Novikov

Shear viscosity of a two-dimensional Fermi liquid is found to be a nonanalytic function of temperature. In contrast to the quasiparticle lifetime that is determined by the forward-scattering processes, the main contribution to the viscosity arises from the quasiparticle scattering in the Cooper channel. The viscosity is enhanced by the logarithmic singularit

A. Donev, F. H. Stillinger, S. Torquato

We demonstrate that there is no ideal glass transition in a binary hard-disk mixture by explicitly constructing an exponential number of jammed packings with densities spanning the spectrum from the accepted ``amorphous&#39;&#39; glassy state to the phase-separated crystal. Thus the configurational entropy cannot be zero for an ideal amorphous glass, presume

G. Alvarez, H. Aliaga, C. Sen, E. Dagotto

Using Monte Carlo simulations and the two eg-orbital model for manganites, the stability of the CE and A-type antiferromagnetic insulating states is analyzed when quenched disorder in the superexchange JAF between the t2g localized spins and in the on-site energies is introduced. At vanishing or small values of the electron-(Jahn-Teller)phonon coupling, the

N. Pimparkar, J. Guo, M. A. Alam

Nanobundle network transistors (NBTs) have emerged as a viable, higher performance alternative to poly-silicon and organic transistors with possible applications in macroelectronic displays, chemical/biological sensors, and photovoltaics. A simple analytical model for I-V characteristics of NBTs (below the percolation limit) is proposed and validated by nume

Nan Gu, M. Mihalkovic, C. L. Henley

We use energy minimization principles to predict the structure of a decagonal quasicrystal - d(AlCoNi) - in the Cobalt-rich phase. Monte Carlo methods are then used to explore configurations while relaxation and molecular dynamics are used to obtain a more realistic structure once a low energy configuration has been found. We find five-fold symmetric decagon

R. Silva

We have investigated the proof of the $H$ theorem within a manifestly covariant approach by considering the relativistic statistical theory developed in [Phy. Rev. E {\bf 66}, 056125, 2002; {\it ibid.} {\bf 72}, 036108 2005]. In our analysis, however, we have not considered the so-called deformed mathematics as did in the above reference. As it happens in th

R. Silva, J. S. Alcaniz, J. A. S. Lima

We discuss experimental constraints on the free parameter of the nonextensive kinetic theory from measurements of the thermal dispersion relation in a collisionless plasma. For electrostatic plane-wave propagation, we show through a statistical analysis that a good agreement between theory and experiment is possible if the allowed values of the $q$-parameter

M. J. Manfra, Z. Jiang, S. H. Simon, L. N. Pfeiffer

Anisotropic charge transport is observed in a two-dimensional (2D) hole system in a perpendicular magnetic field at filling factors nu=7/2 and nu=11/2 for temperatures below 150mK. In stark contrast, the transport at nu=9/2 is isotropic for all temperatures. Our results for a two-dimensional hole system differ substantially from 2D electron transport where n

L. Becu, S. Manneville, A. Colin

The nonlinear rheological response of soft glassy materials is addressed experimentally by focusing on concentrated emulsions where interdroplet attraction is tuned through varying the surfactant content. Velocity profiles are recorded using ultrasonic velocimetry simultaneously to global rheological data in the Couette geometry. Our data show that non-adhes

Ganesh R, Saugata Ghosh

We study delocalization transition in a many body system in two dimension. We identify the presence of a complex vector potential that gives rise to this transition.

Wen-Xu Wang, Gang Yan, Jie Ren, Bing-Hong Wang

We present a renormalization-grouplike method performed in the state space for detecting the dynamical behaviors of large scale-free Boolean networks, especially for the chaotic regime as well as the edge of chaos. Numerical simulations with different coarse-graining level show that the state space networks of scale-free Boolean networks follow universal pow

A. Harju, H. Saarikoski, E. Rasanen

Emergence of half-integer filling factor states, such as nu=5/2 and 7/2, is found in quantum dots by using numerical many-electron methods. These states have interesting similarities and differences with their counterstates found in the two-dimensional electron gas. The nu=1/2 states in quantum dots are shown to have high overlaps with the composite fermion

R. Klingeler, J. Geck, S. Arumugam, N. Tristan

We report on the pressure effects on the orbital polaron lattice in the lightly doped manganites $\mathrm{La_{1-x}Sr_xMnO_{3}}$, with $x\sim 1/8$. The dependence of the orbital polaron lattice on $negative$ chemical pressure is studied by substituting Pr for La in $\mathrm{(La_{1-y}Pr_y)_{7/8}Sr_{1/8}MnO_{3}}$. In addition, we have studied its hydrostatic pr

JunYan Luo, Xin-Qi Li, YiJing Yan

Based on our recent work on quantum transport [Li et al., Phys. Rev. B 71, 205304 (2005)], where the calculation of transport current by means of quantum master equation was presented, in this paper we show how an efficient calculation can be performed for the transport noise spectrum. Compared to the longstanding classical rate equation or the recently prop

Allan D. Boardman, Peter Egan, Larry Velasco, Neil King

The evidence that double negative media, with an effective negative permittivity, and an effective negative permeability, can be manufactured to operate at frequencies ranging from microwave to optical is ushering in a new era of metamaterials. They are referred to here as &#39;left-handed&#39;, even though a variety of names is evident from the literature.

G. I. Japaridze, E. Pogosyan

We have studied the ground state phase diagram of a spin ladder with alternating rung exchange $J^{n}_{\perp} = J_{\perp}[1 + (-1)^{n} δ]$ in a magnetic filed, in the limit where the rung coupling is dominant. In this limit the model is mapped onto an $XXZ$ Heisenberg chain in a uniform and staggered longitudinal magnetic fields, where the amplitude of the s

Federica Lo Verso, Christos N. Likos, Christian Mayer, Hartmut Loewen

Conformational properties of star-shaped polymer aggregates that carry attractive end-groups, called telechelic star polymers, are investigated by simulation and analytical variational theory. We focus on the case of low telechelic star polymer functionalities, $f \leq 5$, a condition which allows aggregation of all attractive monomers on one site. We establ

F. Song, H. Beckmann, G. Bergmann

The anomalous Hall effect of Fe(CsAu) is investigated. Electrons with spin up and down experience a different degree of specular reflection at the FeCs interface. This yields a different mean free path for the two spin orientations. In the presence of an electric field parallel to the film plane one obtains a spin current in addition to the charge current. I

K. Mamiya, T. Koide, A. Fujimori, H. Tokano

Soft x-ray magnetic circular dichroism (XMCD) measurements at the Co L2,3 edges of Co doped rutile TiO2 at room temperature have revealed clear multiplet features characteristic of ferromagnetic Co2+ ions coordinated by O2- ions, being in sharp contrast to the featureless XMCD spectrum of Co metal or metallic clusters. The absorption and XMCD spectra agree w

Yoichi Asada

We develop a new numerical method to calculate the Landauer conductance through an interacting electron system in the first order perturbation or in the self-consistent Hartree-Fock approximation. It is applied to one and two dimensional systems with nearest-neighbor electron-electron interaction.

G. C. Lau, R. S. Freitas, B. G. Ueland, B. D. Muegge

The third law of thermodynamics dictates that the entropy of a system in thermal equilibrium goes to zero as its temperature approaches absolute zero. In ice, however, a &#34;zero point&#34; or residual entropy can be measured - attributable to a high degeneracy in the energetically preferred positions of the hydrogen ions associated with the so-called &#34;

Tuson Park, F. Ronning, H. Q. Yuan, M. B. Salamon

With understood exceptions, conventional superconductivity does not coexist with long-range magnetic order[1]. In contrast, unconventional superconductivity develops near a boundary separating magnetically ordered and magnetically disordered phases[2,3]. A maximum in the superconducting transition temperature Tc develops where this boundary extrapolates to T

Bernd Braunecker

We provide an exact finite temperature extension to the recently developed Riemann-Hilbert approach for the calculation of response functions in nonadiabatically perturbed (multi-channel) Fermi gases. We give a precise definition of the finite temperature Riemann-Hilbert problem and show that it is equivalent to a zero temperature problem. Using this equival

Gennady Margolin, Vladimir Protasenko, Masaru Kuno, Eli Barkai

We quantify nonergodic and aging behaviors of nanocrystals (or quantum dots) based on stochastic model. Ergodicity breaking is characterized based on time average intensity and time average correlation function, which remain random even in the limit of long measurement time. We argue that certain aspects of nonergodicity can be explained based on a modificat

Philip F. Hopkins, Lars Hernquist

Using a simple description of feedback from black hole (BH) growth, we develop an analytic model for the fueling of Seyferts (low-luminosity AGN) and their relation to their host galaxies, Eddington ratio distributions, and cosmological evolution. We derive a solution for evolution of accretion rates in a feedback-driven blast wave, applicable to large-scale

Edo Berger

We present radio observations of a comprehensive sample of 90 dwarf stars and brown dwarfs ranging from spectral type M5 to T8. We detect three radio active sources in addition to the six objects previously detected in quiescence and outburst, leading to an overall detection rate of about 10% for objects later than M7. From the properties of the radio emissi

C. Scannapieco, P. B. Tissera, S. D. M. White, V. Springel

We study the effects of Supernova (SN) feedback on the formation of disc galaxies. For that purpose we run simulations using the extended version of the code GADGET-2 which includes a treatment of chemical and energy feedback by SN explosions. We found that our model succeeds in setting a self-regulated star formation process since an important fraction of t