March 2006 arXiv papers — page 12

D. I. Kamenev, G. P. Berman, V. I. Tsifrinovich

Creation of entanglement is considered theoretically and numerically in an ensemble of spin chains with dipole-dipole interaction between the spins. The unwanted effect of the long-range dipole interaction is compensated by the optimal choice of the parameters of radio-frequency pulses implementing the protocol. The errors caused by (i) the influence of the

Michael R. Geller, Emily J. Pritchett, Andrew T. Sornborger, F. K. Wilhelm

Josephson junctions have demonstrated enormous potential as qubits for scalable quantum computing architectures. Here we discuss the current approaches for making multi-qubit circuits and performing quantum information processing with them.

Li-Xiang Cen, Z. D. Wang, S. J. Wang

We propose a decoherence-free subspaces (DFS) scheme to realize scalable quantum computation with trapped ions. The spin-dependent Coulomb interaction is exploited, and the universal set of unconventional geometric quantum gates is achieved in encoded subspaces that are immune from decoherence by collective dephasing. The scalability of the scheme for the io

D. E. Chang, A. S. Sorensen, P. R. Hemmer, M. D. Lukin

We propose a method that enables strong, coherent coupling between individual optical emitters and electromagnetic excitations in conducting nano-structures. The excitations are optical plasmons that can be localized to sub-wavelength dimensions. Under realistic conditions, the tight confinement causes optical emission to be almost entirely directed into the

Artemio Gonzalez-Lopez, Toshiaki Tanaka

We recall the importance of recognizing the different mathematical nature of various concepts relating to PT-symmetric quantum theories. After clarifying the relation between supersymmetry and pseudo-supersymmetry, we prove generically that nonlinear pseudo-supersymmetry, recently proposed by Sinha and Roy, is just a special case of N-fold supersymmetry. In

Rahul Jain

We consider the problem of remote state preparation recently studied in several papers. We study the communication complexity of this problem, in the presence of entanglement and in the scenario of single use of the channel.

Manfred Bucher

Omission of Bohr's second postulate permits a derivation of spectral intensity. The transition amplitudes serve as upper bounds to quantum mechanical matrix elements. They also provide insight into the latter in terms of Sommerfeld ellipses and transition trajectories. The speed of a nascent photon in the region of the electron transiton is addressed and

Frantisek Sanda, Shaul Mukamel

The stochastic Liouville equations are employed to investigate the combined signatures of chemical exchange (two-state-jump) and spectral diffusion (coupling to an overdamped Brownian oscillator) in the coherent response of an anharmonic vibration to three femtosecond infrared pulses. Simulations reproduce the main features recently observed in the OD stretc

N. J. Sircombe, T. D. Arber, R. O. Dendy

Recent experimental results from the Trident laser confirm the importance of kinetic effects in determining laser reflectivities at high intensities. Examples observed include scattering from low frequency electron acoustic waves (EAWs), and the first few stages of a cascade towards turbulence through the Langmuir decay instability. Interpretive and predicti

H. Schmitz, R. Grauer

The standard approach for integrating the multidimensional Vlasov equation using grid based, conservative schemes is based on a time splitting approach. Here, we show that although the truncation error is of second order, time splitting can introduce systematic heating of the plasma. We introduce a backsubstitution method, which not only avoids this deficien

Manuel Dorado Gonzalez

Using the Hamiltonian formulation, we have attempted to obtain the equations of motion of systems with internal angular momentum that are moving with respect to a reference system when subjected to an interaction. This interaction involves the application of a torque that is permanently perpendicular to the internal angular momentum vector.

R. Battesti, B. Pinto Da Souza, C. Rizzo, C. Robilliard

The basic assumption of the authors of manuscript arXiv:physics/0603175v1 (21 Mar 2006) is that a laser wave differs from a plane wave because of photon coherence. This is not true and therefore their conclusion is also wrong.

N. Arcis, D. F. Escande, M. Ottaviani

The saturation of the tearing mode instability is described within the standard framework of reduced magnetohydrodynamics (RMHD) in the case of an $r$-dependent or of a uniform resistivity profile. Using the technique of matched asymptotic expansions, where the perturbation parameter is the island width $w$, the problem can be solved in two ways: with the so

B. Huke, M. Luecke

We consider the bifurcation scenario that is found in Rayleigh-Benard convection of binary fluid mixtures like ethanol-water at positive separation ratios and small Lewis numbers leading to a bifurcation sequence of square, oscillatory crossroll, stationary crossroll, and roll patterns. We propose a system of four coupled amplitudes that is capable to model

Christian R. Rosberg, Dragomir N. Neshev, Wieslaw Krolikowski, Arnan Mitchell

We report on the first observation of surface gap solitons, recently predicted to exist at the interface between uniform and periodic dielectric media with defocusing nonlinearity [Ya.V. Kartashov et al., Phys. Rev. Lett. 96, 073901 (2006). We demonstrate strong self-trapping at the edge of a LiNbO_3 waveguide array and the formation of staggered surface sol

Alec Maassen van den Brink, K. Young, M. H. Yung

Correlation functions $C(t) \sim <ϕ(t)ϕ(0)>$ in ohmically damped systems such as coupled harmonic oscillators or optical resonators can be expressed as a single sum over modes $j$ (which are not power-orthogonal), with each term multiplied by the Petermann factor (PF) $C_j$, leading to &#34;excess noise&#34; when $|C_j| > 1$. It is shown that $|C_j| > 1$ is

Muslema Pervin, W. Roberts, S. Capstick

The semileptonic decays of $Ω_c$ and $Ω_b$ are treated in the framework of a constituent quark model developed in a previous paper on the semileptonic decays of heavy $Λ$ baryons. Analytic results for the form factors for the decays to ground states and a number of excited states are evaluated. For $Ω_b$ to $Ω_c$ the form factors obtained are shown to satisf

B. B. Back, PHOBOS Collaboration

Forward-backward correlations of charged-particle multiplicities in symmetric bins in pseudorapidity are studied in order to gain insight into the underlying correlation structure of particle production in Au+Au collisions. The PHOBOS detector is used to measure integrated multiplicities in bins centered at eta, defined within |eta|<3, and covering intervals

A. Mukherjee, Subinit Roy, M. K. Pradhan, M. Saha Sarkar

Complete fusion excitations for 11,10B+159Tb have been measured at energies around the respective Coulomb barriers, and the existing complete fusion measurements for 7Li+159Tb have been extended to higher energies. The measurements show significant reduction of complete fusion cross sections at above-barrier energies for both the reactions, 10B+159Tb and 7Li

Maurice Courbage, Brunon Kaminski

Space-time directional Lyapunov exponents are introduced. They describe the maximal velocity of propagation to the right or to the left of fronts of perturbations in a frame moving with a given velocity. The continuity of these exponents as function of the velocity and an inequality relating them to the directional entropy is proved.

Maxim V. Pavlov

New approach in classification of integrable hydrodynamic chains is established. This is the method of the Hamiltonian hydrodynamic reductions. Simultaneously, this approach yields explicit Hamiltonian hydrodynamic reductions of the Hamiltonian hydrodynamic chains. The concept of reducible Poisson brackets is established. Also this approach is useful for non

Maxim V. Pavlov

Necessary and sufficient conditions for an existence of the Poisson brackets significantly simplify in the Liouville coordinates. The corresponding equations can be integrated. Thus, a description of local Hamiltonian structures is a first step in a description of integrable hydrodynamic chains. The concept of $M$ Poisson bracket is introduced. Several new P

Gautam C Sethia, Abhijit Sen

Bursting is a periodic transition between a quiescent state and a state of repetitive spiking. The phenomenon is ubiquitous in a variety of neurophysical systems. We numerically study the dynamical properties of a normal form of subcritical Hopf oscillator (at the bifurcation point) subjected to a nonlinear feedback. This dynamical system shows an infinite-p

Gautam C Sethia, Abhijit Sen

The spiking properties of a subcritical Hopf oscillator with a time delayed nonlinear feedback is investigated. Finite time delay is found to significantly affect both the statistics and the fine structure of the spiking behavior. These dynamical changes are explained in terms of the fundamental modifications occurring in the bifurcation scenario of the syst

Liang Wu, Shiqun Zhu, Juan Li

Two types of synchronization, Achronal Synchronization and Isochronous synchronization are investigated numerically when unidirectionally coupled laser systems are considered both on fast and slow dynamics by studying the correlation function. Although the synchronization behaviors are found to be separated on relatively fast dynamics of chaotic fluctuations

Cosma Rohilla Shalizi

In this chapter, I review the main methods and techniques of complex systems science. As a first step, I distinguish among the broad patterns which recur across complex systems, the topics complex systems science commonly studies, the tools employed, and the foundational science of complex systems. The focus of this chapter is overwhelmingly on the third hea

Bruno Nachtergaele, Yoshiko Ogata, Robert Sims

We provide a simple proof of the Lieb-Robinson bound and use it to prove the existence of the dynamics for interactions with polynomial decay. We then use our results to demonstrate that there is an upper bound on the rate at which correlations between observables with separated support can accumulate as a consequence of the dynamics.

Michael Grasseau

Jets frames, that is a generalisation of ordinary frames on a manifold, are described in a language similar to that of gauge theory. This is achieved by constructing the Cartan geometry of a manifold with respect to the diffeomorphism symmetry. This point of vue allows to give new insights and interpretations in the theory of jet frames, in particular by mak

Valentin Zagrebnov, Joseph V. Pulé

We give a two parameter variational formula for the grand-canonical pressure of the Pair Boson Hamiltonian model. By using the Approximating Hamiltonian Method we provide a rigorous proof of this variational principle.

Zhou Gang, I. M. Sigal

In this paper we study dynamics of solitons in the generalized nonlinear Schrödinger equation (NLS) with an external potential in all dimensions except for 2. For a certain class of nonlinearities such an equation has solutions which are periodic in time and exponentially decaying in space, centered near different critical points of the potential. We call th

Mario Eudave-Munoz, Max Neumann-Coto

We consider closed acylindrical surfaces in 3-manifolds and in knot and link complements, and show that the genus of these surfaces is bounded linearly by the number of tetrahedra in the triangulation of the manifold and by the number of rational (or alternating) tangles in a projection of a link (or knot). For each g we find knots with tunnel number 2 and m

K. Benmeriem, C. Bouzar

The aim of this paper is to prove that the well known non solvable Mizohata type partial differential equations have Colombeau generalized solutions which are distributions if and only if they are solv- able in the space of Schwartz distributions. Therefore the Colombeau generalized solvability includes both a new solution concept and new mathematical object

A. Yu. Khrennikov, S. V. Kozyrev

Gaussian random field on general ultrametric space is introduced as a solution of pseudodifferential stochastic equation. Covariation of the introduced random field is computed with the help of wavelet analysis on ultrametric spaces. Notion of ultrametric Markovianity, which describes independence of contributions to random field from different ultrametric b

Jose Seade

Indices of vector fields on (complex analytic) singular varieties have been considered by various authors from several different viewpoints. All these indices coincide with the classical local index of Poincaré-Hopf when the ambient variety is a smooth manifold. One has the Schwartz index, the local Euler obstruction, the GSV-index, the virtual index and the

W. B. Vasantha Kandasamy, Florentin Smarandache

In this book, for the first time we introduce the notion of neutrosophic algebraic structures for groups, loops, semigroups and groupoids; and also their neutrosophic N-algebraic structures. One is fully aware of the fact that many classical theorems like Lagrange, Sylow and Cauchy have been studied only in the context of finite groups. Here we try to shift

Xian-Yuan Wu, Yu Zhang

We consider the supercritical oriented percolation model. Let ${\fK}$ be all the percolation points. For each $u\in {\fK}$, we write $γ_u$ as its right-most path. Let $G=\cup_u γ_u$. In this paper, we show that $G$ is a single tree with only one topological end. We also present a relationship between ${\fK}$ and $G$ and construct a bijection between ${\fK}$

Robert B. Burckel, Donald E. Marshall, Pietro Poggi-Corradini

The now canonical proof of Schwarz&#39;s Lemma appeared in a 1907 paper of Carathéodory, who attributed it to Erhard Schmidt. Since then, Schwarz&#39;s Lemma has acquired considerable fame, with multiple extensions and generalizations. Much less known is that, in the same year 1907, Landau and Toeplitz obtained a similar result where the diameter of the imag

Salem Said, Nicolas Le Bihan, Stephen J. Sangwine

A discrete complexified quaternion Fourier transform is introduced. This is a generalization of the discrete quaternion Fourier transform to the case where either or both of the signal/image and the transform kernel are complex quaternion-valued. It is shown how to compute the transform using four standard complex Fourier transforms and the properties of the

Allen Hatcher, Karen Vogtmann, Nathalie Wahl

We correct the proof of Theorem 5 of the paper Homology stability for outer automorphism groups of free groups, by the first two authors.

Michael Blank

We study raw coding of trajectories of a chaotic dynamical system by sequences of elements from a finite alphabet and show that there is a fundamental constraint on differences between codes corresponding to different trajectories of the dynamical system.

Marc Kesseböhmer, Bernd O. Stratmann

In this paper we investigate aspects of rigidity and flexibility for conformal iterated function systems. For the case in which the systems are not essentially affine we show that two such systems are conformal equivalent if and only if in each of their Lyapunov spectra there exists at least one level set such that the corresponding Gibbs measures coincide.

Guy Barles, Olivier Ley

We study nonlocal first-order equations arising in the theory of dislocations. We prove the existence and uniqueness of the solutions of these equations in the case of positive and negative velocities, under suitable regularity assumptions on the initial data and the velocity. These results are based on new $L^1$-type estimates on the viscosity solutions of

Jianguo Cao, Hongyan Tang

We will present a new proof of the Gromoll-Grove diameter rigidity theorem.

Vladimir Maz&#39;ya, Robert McOwen

We consider weak solutions of the adjoint equation for an elliptic operator in nondivergent form, and their asymptotic properties at an interior point. We assume that the coefficients a_{ij} are bounded, measurable, complex-valued functions that approach δ_{ij}, but possibly at a slow rate. Our main result is an explicit formula for the leading asymptotic te

Meinolf Geck, Nicolas Jacon

More than 10 years ago, Dipper, James and Murphy developped the theory of Specht modules for Hecke algebras of type $B\_n$. More recently, using Lusztig&#39;s a-function, Geck and Rouquier showed how to obtain parametrisations of the irreducible representations of Hecke algebras (of any finite type) in terms of so-called canonical basic sets. For certain val

Mans Henningson

We consider $(3+1)$-dimensional $SU(N)/\mathbb Z_N$ Yang-Mills theory on a space-time with a compact spatial direction, and prove the following result: Under a continuous increase of the theta angle $θ\toθ+2π$, a &#39;t Hooft operator $T(γ)$ associated with a closed spatial curve $γ$ that winds around the compact direction undergoes a monodromy $T(γ) \to T^\

Maxime Imbeault, Alakabha Datta, and David London

In this paper, we propose a general approach for describing hadronic B decays. Using this method, all amplitudes for such decays can be expressed in terms of contractions, though the matrix elements are not evaluated. Many years ago, Buras and Silvestrini proposed a similar approach. However, our technique goes beyond theirs in several ways. First, we includ

C. P. Buszello, P. Marquard

We explore the possibilities to determine the spin/CP properties of the Higgs boson at the LHC. To cover the mass region below the ZZ threshold we make use of the properties of the production in Weak Boson Fusion (WBF) and the decay chain H -> WW -> l nu l nu. In particular, we study the angular correlations of the forward jets and the distribution of the in

J. T. Londergan, D. P. Murdock, A. W. Thomas

Recent phenomenological work has examined two different ways of including charge symmetry violation in parton distribution functions. First, a global phenomenological fit to high energy data has included charge symmetry breaking terms, leading to limits on the magnitude of parton charge symmetry breaking. In a second approach, two groups have included the co

Naoyuki Haba, Werner Rodejohann

Supersymmetry broken by anomaly mediation suffers from tachyonic slepton masses. A possible solution to this problem results in &#34;decoupling&#34;, i.e., the first two generations of sfermions are much heavier than the third one. We note that in this scenario a sizable loop-induced contribution to the neutrino mass matrix results. As an application of this

G. K. Leontaris J. Rizos

We describe the basic features of model building in the context of intersecting D-branes. As an example, a D-brane inspired construction with U(3)_C X U(3)_L X U(3)_R gauge symmetry is proposed -which is the analogue of the Trinification model- where the unification porperties and some low energy implications on the fermion masses are analysed

Malcolm H. Mac Gregor

Threshold-state elementary particle lifetimes exhibit a scaling in powers of alpha = e^2/hslash*c, and a reciprocal electron-based 1/alpha scaling in particle masses that extends over two powers of 1/alpha. The m(e)/alpha coupling generates accurate q = (u,d), s, c, b quark masses for particles up to 11 GeV. The m(e)/alpha^2 coupling creates the &#34;alpha-q

Hongting Yang

This paper has been withdrawn by the author due to the unsure solutions to the Dyson-Schwinger equation.

Hongting Yang

The values of quark condensate and tensor susceptibility of QCD vacuum are calculated with different number of flavors. It is shown that, the values of tensor susceptibility are obviously dependent on the flavor numbers while the flavor-number dependence of quark condensate is undetermined.

Hongting Yang

This paper has been withdrawn by the author due to the unsure solution to the Dyson-Schwinger equation.

Luca Tagliacozzo

We study the two-point correlator of a modified Confined-Coulomb transition order parameter in four dimensional compact U(1) lattice gauge theory with Wilson action. Its long distance behavior in the confined phase turns out to be governed by a single particle decay. The mass of this particle is computed and found to be in agreement with previous calculation

Chad R. Galley, B. L. Hu, Shih-Yuin Lin

We provide a quantum field theoretical derivation of the Abraham-Lorentz-Dirac (ALD) equation, describing the motion of an electric point charge sourcing an electromagnetic field, which back-reacts on the charge as a self-force, and the Mino-Sasaki-Tanaka-Quinn-Wald (MSTQW) equation describing the motion of a point mass with self-force interacting with the l

Bindu A. Bambah, K. V. S. Shiv Chaitanya, C. Mukku

We use the general formalism of squeezed rotated states to calculate baryon asymmetry in the wake of inflation through parametric amplification. We base our analysis on a B and CP violating Lagrangian in an isotropically expanding universe. The B and CP violating terms originate from the coupling of complex fields with non-zero baryon number to a complex bac

Alessandro Pesci

A spherically symmetric distribution of classical blackbody radiation is considered, at conditions in which gravitational self-interaction effects become not negligible. Static solutions to Einstein field equations are searched for, for each choice of the assumed central energy density. Spherical cavities at thermodynamic equilibrium, i.e. filled with blackb

C. Mukku

Non-Abelian gauge fields are traditionally not coupled to torsion due to violation of gauge invariance. However, it is possible to couple torsion to Yang-Mills fields while maintaining gauge invariance provided one accepts that the gauge couplings then become scalar fields. In the past this has been untenable from experimental constraints at the current epoc

Lorenzo Iorio

In this paper we explicitly work out the effects that a spherically symmetric distribution of dark matter with constant density would induce on the Keplerian orbital elements of the Solar System planets and compare them with the latest results in planetary orbit determination from the EPM2004 ephemerides. It turns out that the longitudes of perihelia and the

Hunter Monroe

Time dilation $\frac{1}{\sqrt{1-v^2}}$ and relative velocity $v$ are observationally indistinguishable in the special theory of relativity, a duality that carries over into the general theory under Fermi coordinates along a curve (in coordinate-independent language, in the tangent Minkowski space along the curve). For example, on a clock stationary at radius

Daniel Brown

An analysis is made of a moving disturbance using a directed cyclic graph. A statistical approach is used to calculate the alternative positions in space and state of the disturbance with a defined observed time. The probability for a freely moving entity interacting in a particular spatial position is calculated and a formulation is derived for the minimum

Daniel Brown

A cellular automata approach using a Directed Cyclic Graph is used to model interrelationships of fluctuating time, state and space. This model predicts phenomena including a constant and maximum speed at which any moving entity can travel, time dilation effects in accordance with special relativity, calculation for the Doppler effect, propagation in three s

Massimiliano Siti, Michael P. Fitz

In multiple-input multiple-output (MIMO) fading channels maximum likelihood (ML) detection is desirable to achieve high performance, but its complexity grows exponentially with the spectral efficiency. The current state of the art in MIMO detection is list decoding and lattice decoding. This paper proposes a new class of lattice detectors that combines some

Dmitry V. Matyushov

This study considers electronic transitions within donor-acceptor complexes dissolved in media with macroscopic polarization. The change of the polarizability of the donor-acceptor complex in the course of electronic transition couples to the reaction field of the polar environment and the electric field created by the macroscopic polarization. An analytical

V. A. Stephanovich

We discuss the influence of disorder on domain structure formation in ferromagnetic phase of diluted magnetic semiconductors (DMS) of p-type. Using analytical arguments we show the existence of critical ratio $ν_{\rm {cr}}$ of concentration of charge carriers and magnetic ions such that sample critical thickness $L_{\rm{cr}}$ (such that at $L<L_{\rm{cr}}$ a

Igor Teper, Yu-Ju Lin, Vladan Vuletic

We use an optical cavity to detect single atoms magnetically trapped on an atom chip. We implement the detection using both fluorescence into the cavity and reduction in cavity transmission due to the presence of atoms. In fluorescence, we register 2.0(2) photon counts per atom, which allows us to detect single atoms with 75% efficiency in 250 microseconds.

Joseph W. Bennett, Ilya Grinberg, Andrew M. Rappe

We use first-principles density functional theory calculations to investigate the dielectric response of BaZrO$_3$ perovskite. A previous study [Arkbarzadeh {\em et al.} Phys. Rev. B {\bf 72}, 205104 (2005)] reported a disagreement between experimental and theoretical low temperature dielectric constant $ε$ for the high symmetry BaZrO$_3$ structure. We show

Brandon C. Wood, Nicola Marzari

Using extensive first-principles molecular dynamics calculations, we characterize the superionic phase transition and the lattice and electronic structures of the archetypal Type-I superionic conductor alpha-AgI. We find that superionicity is signalled by a phase transition of the silver ions alone. In the superionic phase, the first silver shell surrounding

Y. Gallais, T. H. Kirschenmann, C. F. Hirjibehedin, I. Dujovne

We report inelastic light scattering experiments in the fractional quantum Hall regime at filling factors $ν\lesssim1/3$. A spin mode is observed below the Zeeman energy. The filling factor dependence of the mode energy is consistent with its assignment to spin flip excitations of composite fermions with four attached flux quanta ($ϕ$=4). Our findings reveal

Z. Donkó, J. Goree, P. Hartmann, K. Kutasi

A two-dimensional Yukawa liquid is studied using two different nonequilibrium molecular dynamics simulation methods. Shear viscosity values in the limit of small shear rates are reported for a wide range of Coulomb coupling parameter and screening length. At high shear rates it is demonstrated that this liquid exhibits shear thinning, i.e., the viscosity $η$

J. M. P. Carmelo, D. Bozi, P. D. Sacramento

In this paper we study the scattering theory associated with the pseudofermion dynamical theory for the Hubbard chain. In terms of pseudofermions the spectral properties are controlled by zero-momentum forward scattering only. The pseudofermion $S$ matrix is expressed as a commutative product of $S$ matrices, each corresponding to an elementary two-pseudofer

Mike Sutherland, Nicolas Doiron-Leyraud, Louis Taillefer, Thomas Weller

We report measurements of the in-plane electrical resistivity $ρ$ and the thermal conductivity $κ$ of the intercalated graphite superconductor C$_6$Yb to temperatures as low as $T_c$/100. When a field is applied along the c-axis, the residual electronic linear term $κ_0/T$ evolves in an exponential manner for $H_{c1} < H < H_{c2}$. This activated behaviour e

Stefanie Russ, Jesper Mellenthin

We apply periodic-orbit theory to calculate the integrated density of states $N(k)$ from the periodic orbits of pseudointegrable polygon and barrier billiards. We show that the results agree so well with the results obtained from direct diagonalization of the Schrödinger equation, that about the first 100 eigenvalues can be obtained directly from the periodi

H. Dassow, R. Lehndorff, D. E. Buergler, M. Buchmeier

We report on current-induced magnetization switching (CIMS) in single- crystalline nanopillars. Fe(14 nm)/Cr(0.9 nm)/Fe(10 nm)/Ag(6 nm)/Fe(2 nm) multilayers are deposited by molecular-beam epitaxy. The central Fe layer is coupled to the thick one by interlayer exchange coupling over Cr. The topmost Fe layer is decoupled (free layer). Nanopillars with 150 nm

L. Benfatto, J. P. Carbotte, F. Marsiglio

We examine the temperature dependence of the optical sum rule in the normal state due to interactions. To be concrete we adopt a weak coupling approach which uses an electron-boson exchange model to describe inelastic scattering of the electrons with a boson, in the Migdal approximation. While a number of recent works attribute the temperature dependence in

J. Rivas, J. Mira, B. Rivas-Murias, A. Fondado

We report a rather high dependence of the dielectric permittivity on the magnetic field in La2/3Ca1/3MnO3. The variation is maximum at around 270 K, little above the Curie temperature, TC, and it reaches a 30% under only 0.5 T. We attribute this phenomenon to the space-charge or interfacial polarization produced between the insulator and the metallic regions

P. Arun

Crystalline nanoparticles of cadmium iodide where suspended in the amorphous matrix of antimony trisulphide. Both materials are layered structured and have large band-gaps however cadmium iodide exhibits polytypism, i.e. it exists in various different crystalline states. Different crystalline states are marked by wholely different dielectric constants which

Enzo Marinari, Guilhem Semerjian

We apply in this article (non rigorous) statistical mechanics methods to the problem of counting long circuits in graphs. The outcomes of this approach have two complementary flavours. On the algorithmic side, we propose an approximate counting procedure, valid in principle for a large class of graphs. On a more theoretical side, we study the typical number

S. S. Sosin, A. I. Smirnov, L. A. Prozorova, G. Balakrishnan

Electron spin resonance study of frustrated pyrochlore Gd2Ti2O7 is performed in a wide frequency band for a temperature range 0.4-30 K, which covers paramagnetic and magnetically ordered phases. The paramagnetic resonance reveals the spectroscopic g-factor about 2.0 and a temperature dependent linewidth. In ordered phases magnetic resonance spectra are disti

Rosa Lopez, Manh-Soo Choi, Ramon Aguado

We investigate transport of Cooper pairs through a double quantum dot (DQD) in the Kondo regime and coupled to superconducting leads. Within the non-perturbative slave boson mean-field theory we evaluate the Josephson current for two different configurations, the DQD coupled in parallel and in series to the leads. We find striking differences between these c

A. D. Rata, H. Braak, D. E. Buergler, S. Cramm

We investigate the structure and magneto-transport properties of thin films of the Co_2Cr_xFe_(1-x)Al full-Heusler compound, which is predicted to be a half-metal by first-principles theoretical calculations. Thin films are deposited by magnetron sputtering at room temperature on various substrates in order to tune the growth from polycrystalline on thermall

A. Agliolo Gallitto, G. Bonsignore, E. Di Gennaro, G. Giunchi

We report results of microwave second-harmonic generation in ceramic samples of MgB2, prepared by different methods. The SH signal has been investigated as a function of the temperature and the static magnetic field. The results are discussed in the framework of models reported in the literature. We show that the peculiarities of the SH signal are related to

Sungmin Lee, Soon-Hyung Yook, Yup Kim

We study the dynamical properties of a diffusing lamb captured by a diffusing lion on the complex networks with various sizes of $N$. We find that the life time <T>$ of a lamb scales as <T>\sim N$ and the survival probability $S(N\to \infty,t)$ becomes finite on scale-free networks with degree exponent $γ>3$. However, $S(N,t)$ for $γ<3$ has a long-living tai

Takenobu Nakamura, Shin-ichi Sasa

We study the statistical properties of many Brownian particles under the We study the statistical properties of many Brownian particles under the influence of both a spatially homogeneous driving force and a periodic potential with period $\ell$ in a two-dimensional space. In particular, we focus on two asymptotic cases, $\ell_{\rm int} \ll \ell$ and $\ell_{

H. Wadati, T. Yoshida, A. Chikamatsu, H. Kumigashira

Nowadays it has become feasible to perform angle-resolved photoemission spectroscopy (ARPES) measurements of transition-metal oxides with three-dimensional perovskite structures owing to the availability of high-quality single crystals of bulk and epitaxial thin films. In this article, we review recent experimental results and interpretation of ARPES data us

Kyle J. Alvine, Diego Pontoni, Oleg G. Shpyrko, Peter S. Pershan

The controlled self-assembly of thiol stabilized gold nanocrystals in a mediating solvent and confined within mesoporous alumina was probed in situ with small angle x-ray scattering. The evolution of the self-assembly process was controlled reversibly via regulated changes in the amount of solvent condensed from an undersaturated vapor. Analysis indicated th

Andrew Dougherty, Thomas Nunnally

We report measurements of the initial growth and subsequent transient response of dendritic crystals of ammonium chloride grown from supersaturated aqueous solution. Starting from a small, nearly spherical seed held in unstable equilibrium, we lower the temperature to initiate growth. The growth speed and tip radius approach the same steady state values inde

M. Rigol, R. T. Scalettar, P. Sengupta, G. G. Batrouni

We study, using quantum Monte Carlo simulations, the energetics of the formation of Mott domains of fermions and bosons trapped on one-dimensional lattices. We show that, in both cases, the sum of kinetic and interaction energies exhibits minima when Mott domains appear in the trap. In addition, we examine the derivatives of the kinetic and interaction energ

Erhai Zhao, Arun Paramekanti

We study a superfluid on a lattice close to a transition into a supersolid phase and show that a uniform superflow in the homogeneous superfluid can drive the roton gap to zero. This leads to supersolid order around the vortex core in the superfluid, with the size of the modulated pattern around the core being related to the bulk superfluid density and roton

R. L. Doretto, A. O. Caldeira, C. Morais Smith

We develop a non-perturbative bosonization approach for bilayer quantum Hall systems at ν_T = 1, which allows us to systematically study the existence of an exciton condensate in these systems. An effective boson model is derived and the excitation spectrum is calculated both in the Bogoliubov and in the Popov approximations. In the latter case, we show that

A. E. Ruiz-Velasco, V. Migenes, V. Slysh, I. E. Val&#39;tts

We present results of a high resolution survey of OH masers in Galactic Star Forming Regions in order to study the maser emission and establish a list of suitable candidates for higher resolution instruments follow up. We used the Very Long Baseline Array (VLBA) to observe the 1665, 1667, 1612 and 1720 MHz OH maser transitions within 41 regions. These are th

Matthew G. Walker, Mario Mateo, Edward W. Olszewski, Jayanta Kumar Pal

We present multifiber echelle radial velocity results for 551 stars in the Sextans dwarf spheroidal galaxy and identify 294 stars as probable Sextans members. The projected velocity dispersion profile of the binned data remains flat to a maximum angular radius of $30^{\prime}$. We introduce a nonparametric technique for estimating the projected velocity disp

M. Gliozzi, R. Sambruna, I. Jung, H. Krawczynski

We present X-ray observations of the blazar Mrk501 obtained with RXTE during 1997, 1998, 1999, 2000, and 2004. The goal of this study is twofold: 1) characterize the long-term X-ray flux and spectral variability of the source with a model-independent analysis, and 2) investigate the X-ray and TeV correlation on long timescales. The spectral and temporal vari

D. J. Radburn-Smith, J. R. Lucey, P. A. Woudt, R. C. Kraan-Korteweg

To further our understanding of the Great Attractor (GA), we have undertaken a redshift survey using the 2dF on the AAT. Clusters and filaments in the GA region were targeted with 25 separate pointings resulting in approximately 2600 new redshifts. Targets included poorly studied X-ray clusters from the CIZA catalogue as well as the Cen-Crux and PKS 1343-601

O. Daigle, C. Carignan, O. Hernandez, L. Chemin

Improved data reduction techniques for 3D data cubes obtained from Fabry-Perot integral field spectroscopy are presented. They provide accurate sky emission subtraction and adaptive spatial binning and smoothing. They help avoiding the effect analogous to the beam smearing, seen in HI radio data, when strong smoothing is applied to 3D data in order to get th

Mustafa A. Amin, Andrei V. Frolov

We present a set of new characteristic frequencies associated with accretion disks around compact objects. These frequencies arise from persistent rotating patterns in the disk that are finite in radial extent and driven purely by the gravity of the central body. Their existence depends on general relativistic corrections to orbital motion and, if observed,

Feng Yuan, Zhi-Qiang Shen, Lei Huang

Recent radio observations by the VLBA at 7 and 3.5 mm produced the high-resolution images of the compact radio source located at the center of our Galaxy--Sgr A*, and detected its wavelength-dependent intrinsic sizes at the two wavelengths. This provides us with a good chance of testing previously-proposed theoretical models for Sgr A*. In this {\em Letter},

S. Komossa, W. Voges, D. Xu, S. Mathur

We present the first systematic study of (non-radio-selected) radio-loud narrow-line Seyfert 1 (NLS1) galaxies. Cross-correlation of the `Catalogue of Quasars and Active Nuclei&#39; with several radio and optical catalogues led to the identification of 11 radio-loud NLS1 candidates including 4 previously known ones. Most of the radio-loud NLS1s are compact,