arXiv papers from June 2006

Frank Simon

The STAR experiment at the Relativistic Heavy Ion Collider (RHIC) has a rich spin physics program aimed at exploring the spin structure of the proton with polarized proton beams. In addition to the currently accessible channels, heavy flavor, charged vector boson production and forward mesons are integral parts of the long-term program. Such measurements req

Toshiyuki Kobayashi, Gen Mano

The minimal representation $\pi$ of the indefinite orthogonal group $O(m+1,2)$ is realized on the Hilbert space of square integrable functions on $\mathbb R^m$ with respect to the measure $|x|^{-1} dx_1... dx_m$. This article gives an explicit integral formula for the holomorphic extension of $\pi$ to a holomorphic semigroup of $O(m+3, \mathbb C)$ by means o

Toshiyuki Kobayashi

Motivated by recent developments on visible actions on complex manifolds, we raise a question whether or not the multiplication of three subgroups $L$, $G'$ and $H$ surjects a Lie group $G$ in the setting that $G/H$ carries a complex structure and contains $G'/G' \cap H$ as a totally real submanifold. Particularly important cases are when $G/L$ and $G/H$ are

V. M. Dmitriev, I. V. Zolochevskii, E. V. Bezuglyi

The temperature dependences of the enhanced critical current in wide and thin Sn films exposed to the microwave field have been investigated experimentally and analyzed. It was found that the microwave field stabilizes the current state of a wide film with respect to the entry of Abrikosov vortices. The stabilizing effect of irradiation increases with freque

Toshiyuki Kobayashi

A visible action on a complex manifold is a holomorphic action that admits a $J$-transversal totally real submanifold $S$. It is said to be strongly visible if there exists an orbit-preserving anti-holomorphic diffeomorphism $\sigma$ such that $\sigma |_S = \mathrm{id}$. In this paper, we prove that for any Hermitian symmetric space $D = G/K$ the action of a

Rajdeep Sensarma, Mohit Randeria, Nandini Trivedi

The question of determining the underlying Fermi surface (FS) that is gapped by superconductivity (SC) is of central importance in strongly correlated systems, particularly in view of angle-resolved photoemission experiments. Here we explore various definitions of the FS in the superconducting state using the zero-energy Green's function, the excitation spec

Toshiyuki Kobayashi

We give a complete proof of a propagation theorem of multiplicity-free property from fibers to spaces of global sections for holomorphic vector bundles. The propagation theorem is formalised in three ways, aiming for producing various multiplicity-free theorems in representation theory for both finite and infinite dimensional cases in a systematic and synthe

J. C. Lopez-Dominguez, O. Obregon, C. Ramirez, M. Sabido

In this paper we study noncommutative black holes. We use a diffeomorphism between the Schwarzschild black hole and the Kantowski-Sachs cosmological model, which is generalized to noncommutative minisuperspace. Through the use of the Feynman-Hibbs procedure we are able to study the thermodynamics of the black hole, in particular, we calculate the Hawking's t

A. V. Plyukhin

The conventional equations of Brownian motion can be derived from the first principles to order $\lambda^2=m/M$, where $m$ and $M$ are the masses of a bath molecule and a Brownian particle respectively. We discuss the extension to order $\lambda^4$ using a perturbation analysis of the Kramers-Moyal expansion. For the momentum distribution such method yields

Radu Laza

We study the deformations of the minimally elliptic surface singularity $N_{16}$. A standard argument reduces the study of the deformations of $N_{16}$ to the study of the moduli space of pairs $(C,L)$ consisting of a plane quintic curve and a line. We construct this moduli space in two ways: via the periods of $K3$ surfaces and by using geometric invariant

Toshiyuki Kobayashi

The complex analytic methods have found a wide range of applications in the study of multiplicity-free representations. This article discusses, in particular, its applications to the question of restricting highest weight modules with respect to reductive symmetric pairs. We present a number of multiplicity-free branching theorems that include the multiplici

Mark Kleiner, Allen Pelley

This paper studies connections between the preprojective modules over the path algebra of a finite connected quiver without oriented cycles, the (+)-admissible sequences of vertices, and the Weyl group. For each preprojective module, there exists a unique up to a certain equivalence shortest (+)-admissible sequence annihilating the module. A (+)-admissible s

M. Amniat-Talab, R. Khoda-Bakhsh, S. Guérin

We propose a robust scheme to generate single-photon Fock states and atom-photon and atom-atom entanglement in atom-cavity systems. We also present a scheme for quantum networking between two cavity nodes using an atomic channel. The mechanism is based on Stark-chirped rapid adiabatic passage (SCRAP) and half-SCRAP processes in a microwave cavity. The engine

Youngki Yoon, Yijian Ouyang, Jing Guo

The effect of phonon scattering on the intrinsic delay and cut-off frequency of Schottky barrier carbon nanotube (CNT) FETs is examined by self-consistently solving the Poisson equation and the Schrodinger equation using the non-equilibrium Greens function (NEGF) formalism. Carriers are mostly scattered by optical and zone boundary phonons beyond the beginni

Christian Marois, Don W. Phillion, Bruce Macintosh

Imaging faint companions (exoplanets and brown dwarfs) around nearby stars is currently limited by speckle noise. To efficiently attenuate this noise, a technique called simultaneous spectral differential imaging (SSDI) can be used. This technique consists of acquiring simultaneously images of the field of view in several adjacent narrow bands and in combini

J. Pollanen, S. Blinstein, H. Choi, J. P. Davis

It may be possible to stabilize new superfluid phases of $^{3}$He with anisotropic silica aerogels. We discuss two methods that introduce anisotropy in the aerogel on length scales relevant to superfluid $^{3}$He. First, anisotropy can be induced with uniaxial strain. A second method generates anisotropy during the growth and drying stages. We have grown cyl

Nicholas Guttenberg, Nigel Goldenfeld

We use analytic and numerical methods to analyze the dynamics of vortices following the quench of a Type-II superconductor under the application of an external magnetic field. In three dimensions, in the absence of a field, the spacing between vortices scales with time t with an exponent phi=0.414 +/- 0.01, In a thin sheet of superconductor, the scaling expo

Marc Freitag, Pau Amaro-Seoane, Vassiliki Kalogera

We study the process of mass segregation through 2-body relaxation in galactic nuclei with a central massive black hole (MBH). This study has bearing on a variety of astrophysical questions, from the distribution of X-ray binaries at the Galactic centre, to tidal disruptions of main-sequence and giant stars, to inspirals of compact objects into the MBH, an i

Bo-Yu Lin, Jie Ren, Hui-Jie Yang, Bing-Hong Wang

Naming Game is a recently proposed model for describing how a multi-agent system can converge towards a consensus state in a self-organized way. In this paper, we investigate this model on the so-called homogeneous small-world networks and focus on the influence of the triangular topology on the dynamics. Of all the topological quantities, the clustering coe

Amjad Ashoorioon, Axel Krause

The power spectrum of M-theory cascade inflation is derived. It possesses three distinctive signatures: a decisive power suppression at small scales, oscillations around the scales that cross the horizon when the inflaton potential jumps and stepwise decrease in the scalar spectral index. All three properties result from features in the inflaton potential. C

John Ellis, Keith A. Olive, Pearl Sandick

We consider the possibility that the soft supersymmetry-breaking parameters m_{1/2} and m_0 of the MSSM are universal at some scale M_{in} below the supersymmetric grand unification scale M_{GUT}, as might occur in scenarios where either the primordial supersymmetry-breaking mechanism or its communication to the observable sector involve a dynamical scale be

Shuichi Murakami

We show that the spin Hall conductivity in insulators is related with a magnetic susceptibility representing the strength of the spin-orbit coupling. We use this relationship as a guiding principle to search real materials showing quantum spin Hall effect. As a result, we theoretically predict that bismuth will show the quantum spin Hall effect, both by calc

T. M. Lippman, J. P. Davis, H. Choi, J. Pollanen

We have performed measurements of the temperature dependence of the magnetoresistance up to 9 T in bulk single crystals of UPt3 with the magnetic field along the b axis, the easy magnetization axis. We have confirmed previous results for transverse magnetoresistance with the current along the c axis, and report measurements of the longitudinal magnetoresista

J. Sun, A. Mikkelsen, M. Fuglsang Jensen, Y. M. Koroteev

The surface structure of Bi(110) has been investigated by low-energy electron diffraction (LEED) intensity analysis and by first-principles calculations. Diffraction patterns at a sample temperature of 110 K and normal incidence reveal a bulk truncated (1$\times$1) surface without indication of any structural reconstruction despite the presence of dangling b

S. R. Beane, P. F. Bedaque, K. Orginos, M. J. Savage

We compute the ratio of pseudoscalar decay constants f_K/f_pi using domain-wall valence quarks and rooted improved Kogut-Susskind sea quarks. By employing continuum chiral perturbation theory, we extract the Gasser-Leutwyler low-energy constant L_5, and extrapolate f_K/f_pi to the physical point. We find: f_K/f_pi = 1.218 (+- 0.002) (+0.011 -0.024) where the

Aybike Catal-Ozer

We study duality-twisted dimensional reductions on a group manifold G, where the twist is in a group \tilde{G} and examine the conditions for consistency. We find that if the duality twist is introduced through a group element \tilde{g} in \tilde{G}, then the flat \tilde{G}-connection A =\tilde{g}^{-1} d\tilde{g} must have constant components M_n with respec

Catherine L. Buchanan, Joel H. Kastner, William J. Forrest, Bruce J. Hrivnak

We present an atlas of Spitzer Space Telescope Infrared Spectrograph (IRS) spectra of highly luminous, compact mid-infrared sources in the Large Magellanic Cloud. Sources were selected on the basis of infrared colors and 8 micron (MSX) fluxes indicative of highly evolved, intermediate- to high-mass stars with current or recent mass loss at large rates. We de

Dana Mihai, George A. J. Sparling

We analyze the decomposition of the enveloping algebra of the conformal algebra in arbitrary dimension with respect to the mass-squared operator. It emerges that the subalgebra that commutes with the mass-squared is generated by its Poincare subalgebra together with a vector operator. The special cases of the conformal algebras of two and three dimensions ar

H. de Riedmatten, J. Laurat, C. W. Chou, E. W. Schomburg

Violations of a Bell inequality are reported for an experiment where one of two entangled qubits is stored in a collective atomic memory for a user-defined time delay. The atomic qubit is found to preserve the violation of a Bell inequality for storage times up to 21 microseconds, 700 times longer than the duration of the excitation pulse that creates the en

N. R. Butler, W. Li, D. Perley, K. Y. Huang

Even with the renaissance in gamma-ray burst (GRB) research fostered by the Swift satellite, few bursts have both contemporaneous observations at long wavelengths and exquisite observations at later times across the electromagnetic spectrum. We present here contemporaneous imaging with the KAIT robotic optical telescope, dense optical sampling with Lulin, an

Koushik Ghosh, Probhas Raychaudhuri

We have used the Ferraz-Mello Method of Date Compensated Discrete Fourier Transform on the solar neutrino flux data from the Sudbury Neutrino Observatory (SNO) in order to search for its time variation. We present results from Ferraz-Mello Method for both pure D2O and salt phase data sets from SNO. For the D2O data the obtained periods are 5.36, 14.99, 23.06

M. Wing

Highlights from the ZEUS experiment at HERA as of the DIS06 conference in April are shown. New results focus on measurements from the HERA II running period of inclusive DIS at high momentum transfer using polarised leptons and on their impact in combined QCD and electroweak fits. Investigation of the hadronic final state, both for inclusive and diffractive

L Kaltenegger, M. Fridlund, A. Karlsson

The requirements on space missions designed to study Terrestrial exoplanets are discussed. We then investigate whether the design of such a mission, specifically the Darwin nulling interferometer, can be carried out in a simplified scenario. The key element here is accepting somewhat higher levels of stellar leakage. We establish detailed requirements result

Vasiliki A. Mitsou

The ATLAS Semiconductor Tracker (SCT) together with the pixel and the transition radiation detectors will form the tracking system of the ATLAS experiment at LHC. It will consist of 20000 single-sided silicon microstrip sensors assembled back-to-back into modules mounted on four concentric barrels and two end-cap detectors formed by nine disks each. The SCT

M. Diez-Minguito, P. L. Garrido, J. Marro

We present and study lattice and off-lattice microscopic models in which particles interact via a local anisotropic rule. The rule induces preferential hopping along one direction, so that a net current sets in if allowed by boundary conditions. This may be viewed as an oversimplification of the situation concerning certain traffic and flow problems. The emp

Frank M. Hilker, Frank H. Westerhoff

Interactions in ecological communities are inherently nonlinear and can lead to complex population dynamics including irregular fluctuations induced by chaos. Chaotic population dynamics can exhibit violent oscillations with extremely small or large population abundances that might cause extinction and recurrent outbreaks, respectively. We present a simple m

Misty A. La Vigne, Stuart N. Vogel, Eve C. Ostriker

We present a survey of spiral arm extinction substructure referred to as feathers in 223 spiral galaxies using HST WFPC2 images. The sample includes all galaxies in the RC3 catalog with cz < 5000 km/s, B_T < 15, i < 60 degrees, and types Sa--Sd with well-exposed broadband WFPC2 images. The detection frequency of delineated, periodic feathers in this sample i

Erik Andries, Sabir Umarov, Stanly Steinberg

In this paper the multi-dimensional random walk models governed by distributed fractional order differential equations and multi-term fractional order differential equations are constructed. The scaling limits of these random walks to a diffusion process in the sense of distributions is proved. Simulations based upon multi-term fractional order differential

Orlando Villamayor

The paper is motivated on the open problem of resolution of singularities in positive characteristic. The aim is to present a form of induction which is different from that used by Hironaka. In characteristic zero induction is formulated by restriction to smooth hypersurfaces (hypersurfaces of maximal contact). Our alternative approach, introduced here, repl

Willy Langeveld

Wavefront Coding has been applied as a means to increase the effective depth of focus of optical systems. In this note I discuss the potential for this technique to increase the depth of focus of the LSST and the resulting advantages for the construction and operation of the facility, as well as possible drawbacks. It may be possible to apply Wavefront Codin

Orlando Villamayor

Let $V$ be a smooth scheme over a field $k$, and let $\{I_n, n\geq 0\}$ be a filtration of sheaves of ideals in $\calo_V$, such that $I_0=\calo_V$, and $I_s\cdot I_t\subset I_{s+t}$. In such case $\bigoplus I_n$ is called a Rees algebra. A Rees algebra is said to be a Diff-algebra if, for any two integers $N>n$ and any differential operator $D$ of order $n$,

Aaron S. Chou

We consider the possibility that the ultra-high-energy cosmic ray flux has a small component of exotic particles which create showers much deeper in the atmosphere than ordinary hadronic primaries. It is shown that applying the conventional AGASA/HiRes/Auger data analysis procedures to such exotic events results in large systematic biases in the energy spect

Stefano Forte, Guido Altarelli, Richard D. Ball

We summarize recent progress in the resummation of perturbative evolution at small x. We show that the problem of incorporating BFKL small x logs in GLAP evolution is now completely solved, and that the main effect of small x resummation is to reduce the growth of the gluon at small x in the HERA and LHC regions.

Massimo Giovannini

The tight coupling expansion, appropriately generalized to include large-scale magnetic fields, allows the estimate of the brightness perturbations of CMB anisotropies for typical wavelengths that are larger than the Hubble radius after matter-radiation equality. After discussing the basic features of the the pre-decoupling initial conditions in the presence

N. C. Santos, A. Ecuvillon, G. Israelian, M. Mayor

We used the UVES spectrograph (VLT-UT2 telescope) to obtain high-resolution spectra of 6 stars hosting transiting planets, namely for OGLE-TR-10, 56, 111, 113, 132 and TrES-1. The spectra are now used to derive and discuss the chemical abundances for C, O, Na, Mg, Al, Si, S, Ca, Sc, Ti, V, Cr, Mn, Co, Ni, Cu and Zn. Abundances were derived in LTE, using 1-D

C. Alard

This paper presents a method to identify gravitational arcs or more generally elongated structures in a given image. The method is based on the computation of a local estimator of the elongation. The estimation of the local elongation proceed in two steps: first the local orientation of the structure is computed, then in the next step, a rotation is performe

Sahak Petrosyan, Jean-Francois Briere, David Roundy, T. A. Arias

We introduce a new form of density functional theory for the {\em ab initio} description of electronic systems in contact with a molecular liquid environment. This theory rigorously joins an electron density-functional for the electrons of a solute with a classical density-functional theory for the liquid into a single variational principle for the free ener

Janusz Karkowski

Initial data for boosted Kerr black hole are constructed in an axially symmetric case. Momentum and hamiltonian constraints are solved numerically using finite element method (FEM) algorithms. Both Bowen-York and puncture boundary conditions are adopted and appropriate results are compared. Past and future apparent horizons are also found numerically and the

T. Keller, P. Aynajian, K. Habicht, L. Boeri

Neutron resonance spin-echo spectroscopy was used to monitor the temperature evolution of the linewidths of transverse acoustic phonons in lead across the superconducting transition temperature, $T_c$, over an extended range of the Brillouin zone. For phonons with energies below the superconducting energy gap, a linewidth reduction of maximum amplitude $\sim

B. Neyenhuis, D. Christensen, D. S. Durfee

We discuss using a table-top ion interferometer to search for deviations from Coulomb's inverse-square law. Such deviations would result from non-classical effects such at a non-zero photon rest mass. We discuss the theory behind the proposed measurement, explain which fundamental, experimentally controllable parameters are the relevant figures of merit, and

Nick Dorey, Benoit Vicedo

We define regularised Poisson brackets for the monodromy matrix of classical string theory on R x S^3. The ambiguities associated with Non-Ultra Locality are resolved using the symmetrisation prescription of Maillet. The resulting brackets lead to an infinite tower of Poisson-commuting conserved charges as expected in an integrable system. The brackets are a

J. J. Dong, B. Schmittmann, R. K. P. Zia

This submission is a duplicate of arXiv:q-bio/0602024 and has been removed.

Yu. V. Bludov, V. V. Konotop

It is shown that the mean-field description of a boson-fermion mixture with a dominating fermionic component, loaded in a one-dimensional optical lattice, is reduced to the nonlinear Schr\"{o}dinger equation with a periodic potential and periodic nonlinearity. In such system there exist localized modes having peculiar properties. In particular, for some regi

Lara B Anderson, Adam B Barrett, Andre Lukas, Masahiro Yamaguchi

We reduce M-theory on a G_2 orbifold with co-dimension four singularities, taking explicitly into account the additional gauge fields at the singularities. As a starting point, we use 11-dimensional supergravity coupled to seven-dimensional super-Yang-Mills theory, as derived in a previous paper. The resulting four-dimensional theory has N=1 supersymmetry wi

Junji Hisano, Minoru Nagai, Paride Paradisi

Flavor-changing terms with CP-violating phases in the quark sector may contribute to the hadronic electric dipole moments (EDMs). However, within the Standard Model (SM), the source of CP violation comes from the unique CKM phase, and it turns out that the EDMs are strongly suppressed. This implies that the EDMs are very sensitive to non-minimal flavor viola

M. Eliashvili, G. Tsitsishvili

Area non-preserving transformations in the non-commutative plane are introduced with the aim to map the $\nu=1$ integer quantum Hall effect (IQHE) state on the fractional quantum Hall effect (FQHE) $\nu=\frac{1}{2p+1}$ FQHE states. Using the hydrodynamical description of the quantum Hall fluid, it is shown that these transformations are generated by vector f

M. Wobisch

Photon production rates have been studied by the D0 and CDF experiments in Run II of the Fermilab Tevatron Collider. Measurements of the inclusive isolated photon cross section and the di-photon cross section are presented, based on integrated luminosities of 0.3 fb-1 and 0.2 fb-1, respectively. The results are compared to perturbative QCD calculations in va

Hiroshige Kajiura, Jim Stasheff

This paper is a survey of our previous works on open-closed homotopy algebras, together with geometrical background, especially in terms of compactifications of configuration spaces (one of Fred's specialities) of Riemann surfaces, structures on loop spaces, etc. We newly present Merkulov's geometric A_infty-structure [Internat. Math. Res. Notices (1999) 153

S. P. Bayrakci, T. Keller, K. Habicht, B. Keimer

We use a neutron spin-echo method with $\mu$eV resolution to determine the lifetimes of spin waves in the prototypical antiferromagnet MnF$_2$ over the entire Brillouin zone. A theory based on the interaction of magnons with longitudinal spin fluctuations provides an excellent, parameter-free description of the data, except at the lowest momenta and temperat

Uffe Haagerup, Agata Przybyszewska

In this article it is proved, that every locally compact second countable group has a left invariant metric d, which generates the topology on G, and which is proper, ie. every closed d-bounded set in G is compact. Moreover, we obtain the following extension of a result due to N. Brown and E. Guentner: Every locally compact second countable $G$ admits a prop

Christine Guenther, James Isenberg, Dan Knopf

As a step toward understanding the analytic behavior of Type-III Ricci flow singularities, i.e. immortal solutions that exhibit |Rm|<C/t curvature decay, we examine the linearization of an equivalent flow at fixed points discovered recently by Baird--Danielo and Lott: nongradient homogeneous expanding Ricci solitons on nilpotent or solvable Lie groups. For a

A. Krizhanovsky

HITS adapted algorithm for synonym search, the program architecture, and the program work evaluation with test examples are presented in the paper. Synarcher program for synonym (and related terms) search in the text corpus of special structure (Wikipedia) was developed. The results of search are presented in the form of a graph. It is possible to explore th

C. Bambi, A. D. Dolgov, K. Freese

In models with large extra dimensions, where the fundamental gravity scale can be in the electroweak range, gravitational effects in particle physics may be noticeable even at relatively low energies. In this paper, we perform simple estimates of the decays of elementary particles with a black hole intermediate state. Since black holes are believed to violat

Y. Xian

We extend recently proposed variational coupled-cluster method to describe excitation states of quantum antiferromagnetic bipartite lattices. We reproduce the spin-wave excitations (i.e., magnons with spin $\pm 1$). In addition, we obtain a new, spin-zero excitation (magnon-density waves) which has been missing in all existing spin-wave theories. Within our

Edward H. Hellen, Matthew J. Lanctot

We investigate a simple variation of the series RLC circuit in which anti-parallel diodes replace the resistor. This results in a damped harmonic oscillator with a nonlinear damping term that is maximal at zero current and decreases with an inverse current relation for currents far from zero. A set of nonlinear differential equations for the oscillator circu

P. C. Frisch, J. D. Slavin

Over the recent past, the galactic environment of the Sun has differed substantially from today. Sometime within the past ~130,000 years, and possibly as recent as ~56,000 years ago, the Sun entered the tenuous tepid partially ionized interstellar material now flowing past the Sun. Prior to that, the Sun was in the low density interior of the Local Bubble. A

Lautaro Vergara

In granular media, the characterization of the behavior of solitary waves around interfaces is of importance in order to look for more applications of these systems. We study the behavior of solitary waves at both interfaces of a symmetric granular container, a class of systems that has received recent attention because it posses the feature of energy trappi

G. C. Rossi, E. Sokatchev, Ya. S. Stanev

We prove that the chiral propagator of the deformed N=4 SYM theory can be made finite to all orders in perturbation theory for any complex value of the deformation parameter. For any such value the set of finite deformed theories can be parametrized by a whole complex function of the coupling constant g. We reveal a new protection mechanism for chiral operat

Z. Yamani, B. W. Statt, W. A. MacFarlane, Ruixing Liang

Nuclear magnetic resonance (NMR) measurements of CuO chains of detwinned Ortho-II YBa$_2$Cu$_3$O$_{6.5}$ (YBCO6.5) single crystals reveal unusual and remarkable properties. The chain Cu resonance broadens significantly, but gradually, on cooling from room temperature. The lineshape and its temperature dependence are substantially different from that of a con

Wei Wang, Jianhua Sun, Jinqiao Duan

The ocean thermohaline circulation under uncertainty is investigated by a random dynamical systems approach. It is shown that the asymptotic dynamics of the thermohaline circulation is described by a random attractor and by a system with finite degrees of freedom.

Andrew N. Norris

Conditions for a maximum or minimum of Poisson's ratio of anisotropic elastic materials are derived. For a uniaxial stress in the 1-direction and Poisson's ratio $\nu$ defined by the contraction in the 2-direction, the following three quantities vanish at a stationary value: $s_{14}$, $[2\nu s_{15} + s_{25}]$ and $[(2 \nu -1)s_{16} + s_{26}]$, where $s_{IJ}$

M. J. Washenberger, M. Mobilia, U. C. Tauber

We study a stochastic lattice predator-prey system by means of Monte Carlo simulations that do not impose any restrictions on the number of particles per site, and discuss the similarities and differences of our results with those obtained for site-restricted model variants. In accord with the classic Lotka-Volterra mean-field description, both species alway

Philippe Curty, Hans Beck

Amplitude fluctuations of the pairing field are responsible together with phase fluctuations for the pseudogap phenomena in high temperature superconductors. Here we present the more detailed theory of the amplitude and phase fluctuations approach in the framework of a fermionic pairing model. New experimental comparisons are presented for the specific heat

Lautaro Vergara

It is shown that the phenomenon of self-similarity appears in granular media, with an intergrain potential $V \propto \delta^{p+1}$, $p > 1$, where $\delta$ is the overlap between the grains. Although this fact can be traced back in the literature, this has not been put explicitly.

Johannes Richter, Oleg Derzhko, Taras Krokhmalskii

We investigate the thermodynamic properties of the frustrated bilayer quantum Heisenberg antiferromagnet at low temperatures in the vicinity of the saturation magnetic field. The low-energy degrees of freedom of the spin model are mapped onto a hard-square gas on a square lattice. We use exact diagonalization data for finite spin systems to check the validit

A. Ciardi, S. V. Lebedev, A. Frank, E. G. Blackman

Jets and outflows are thought to be an integral part of accretion phenomena and are associated with a large variety of objects. In these systems, the interaction of magnetic fields with an accretion disk and/or a magnetized central object is thought to be responsible for the acceleration and collimation of plasma into jets and wider angle flows. In this pape

P B Jones

Neutron-star inner cores with several charged baryonic components are likely to be analogues of the two-gap superconductor which is of current interest in condensed-matter physics. Consequently, type I superconductivity is less probable than type II but may nevertheless be present in some intervals of matter density. The intermediate state structure formed a

Diego Garlaschelli, Sebastian E. Ahnert, Thomas M. A. Fink, Guido Caldarelli

Real-world social and economic networks typically display a number of particular topological properties, such as a giant connected component, a broad degree distribution, the small-world property and the presence of communities of densely interconnected nodes. Several models, including ensembles of networks also known in social science as Exponential Random

B. Jancovici

In a recent paper [S.El Boustani, P.R.Buenzli, and Ph.A.Martin, Phys.Rev. E 73, 036113 (2006) cond-mat/0511537], about quantum charges in equilibrium with radiation, among other things the asymptotic form of the electric-field correlation has been obtained by a microscopic calculation. It has been found that this correlation has a long-range algebraic decay

C. G. Papadopoulos, M. Worek

The status of the multi-purpose event generator HELAC is briefly presented. The aim of this tool is the full simulation of events within the Standard Model at current and future high energy experiments, in particular the LHC. Some results related to the production of multi-jet final states at the LHC are also discussed.

A. Bialas, W. Czyz, K. Zalewski

A model-independent lower bound on the entropy S of the multiparticle system produced in high energy collisions, provided by the Renyi entropy H_2, is shown to be very effective. Estimates show that the ratio H_2/S remains close to one half for all realistic values of the parameters.

Luck Darnière

It is known from Grzegorczyk's paper \cite{grze-1951} that the lattice of real semi-algebraic closed subsets of ${\mathbb R}^n$ is undecidable for every integer $n\geq 2$. More generally, if $X$ is any definable set over a real or algebraically closed field $K$, then the lattice $L(X)$ of all definable subsets of $X$ closed in $X$ is undecidable whenever $\d

Stefano Capitani

We present perturbative calculations made with domain-wall fermions which possess a finite number of points $N_s$ in the extra fifth dimension. We have derived the required propagator functions, investigated the one-loop properties of quark amplitudes at finite $N_s$ and evaluated three quantities that can provide insights on chirality-breaking effects from

Dinesh Singh, Nader Mobed, Giorgio Papini

We present the possibility that Dirac and Majorana neutrino wave packets can be distinguished when subject to spin-gravity interaction while propagating through vacuum described by the Lense-Thirring metric. By adopting the techniques of gravitational phase and time-independent perturbation theory following the Brillouin-Wigner method, we generate spin-gravi

V. Kuznetsov, S. Churikova, G. Gervino, F. Ghio

New results on quasi-free $\eta$ photoproduction on the neutron and proton bound in a deuteron target are presented. The $\gamma n \to \eta n$ quasi-free cross section reveals a bump-like structure which is not seen in the cross section on the proton. This structure may signal the existence of a relatively narrow ($M\sim 1.68$ GeV, $\Gamma \leq 30$ MeV) bary

D. Poilblanc, M. Mambrini, A. Laeuchli, F. Mila

We investigate the properties of the two-dimensional frustrated quantum antiferromagnet on the square lattice, especially at infinitesimal doping. We find that next nearest neighbor (N.N.) J2 and next-next N.N. J3 interactions together destroy the antiferromagnetic long range order and stabilize a quantum disordered valence bond crystalline plaquette phase.

Peter Hasenfratz, Ferenc Niedermayer, Reto von Allmen

Finding the relation between the symmetry transformations in the continuum and on the lattice might be a nontrivial task as illustrated by the history of chiral symmetry. Lattice actions induced by a renormalization group procedure inherit all symmetries of the continuum theory. We give a general procedure which gives the corresponding symmetry transformatio

Timothy Logvinenko

In most cases where it had been shown to exist the derived McKay correspondence D(Y) --> D^G(C^n) can be written as a Fourier-Mukai transform which sends point sheaves of the crepant resolution Y to pure sheaves in D^G(C^n). We give a sufficient condition for an object of D^G(Y x C^n) to be the defining object of such a transform. We use it to construct the

A. L. Pirozerski, S. E. Emelin

A new type of pulse high voltage electric discharge through a thin conducting layer on the surface of glass plate has been investigated. The afterglow plasma of this discharge forms quasi-spherical object with a lifetime about 0.2-0.3 s. Electric properties of the objects were studied by electric probe method. Measurements of plasma radiation spectra kinetic

Abdelaziz Mhirech, Hamid Ez-Zahraouy, Assia Alaoui Ismaili

The effect of the on-ramp and off-ramp positions $i_1$ and $i_2$, respectively, on the one dimensional-cellular automaton traffic flow behaviour, is investigated numerically. The on-ramp and off-ramp rates at $i_1$ and $i_2$ are $\alpha_0$ and $\beta_0$, respectively. However, in the open boundary conditions, with injecting and extracting rates $\alpha$ and

Alina Dubrovska Vasilieva

Many quantum algorithms can be analyzed in a query model to compute Boolean functions where input is given by a black box. As in the classical version of decision trees, different kinds of quantum query algorithms are possible: exact, zero-error, bounded-error and even nondeterministic. In this paper, we study the latter class of algorithms. We introduce a f

Doris Folini, Rolf Walder

Colliding hypersonic flows play a decisive role in many astrophysical objects. In this paper, we look at the idealized model of a 2D plane parallel isothermal slab (CDL) and at symmetric settings, where both flows have equal parameters. We performed a set of high-resolution simulations with upwind Mach numbers, 5 < M_u < 90. We find that the CDL is irregular

M. C. Eliche-Moral, M. Balcells, J. A. L. Aguerri, A. C. Gonzalez-Garcia

Satellite accretion events have been invoked for mimicking the internal secular evolutionary processes of bulge growth. However, N-body simulations of satellite accretions have paid little attention to the evolution of bulge photometric parameters, to the processes driving this evolution, and to the consistency of this evolution with observations. We want to

Mariateresa Fiocchi, Angela Bazzano, Pietro Ubertini, Pierre Jean

We report on the spectral analysis results of the neutron star, atoll type, low mass X-ray Binary 4U1636-53 observed by INTEGRAL and BeppoSAX satellites. Spectral behavior in three different epochs corresponding to three different spectral states has been deeply investigated. Two data set spectra show a continuum well described by one or two soft blackbody p

M. V. Costache, M. Zaffalon, B. J. van Wees

We study spin accumulation in an aluminium island, in which the injection of a spin current and the detection of the spin accumulation are done by means of four cobalt electrodes that connect to the island through transparent tunnel barriers. Although the four electrodes are designed as two electrode pairs of the same shape, they nonetheless all exhibit dist

Mees de Roo, Dennis B. Westra, Sudhakar Panda

We investigate a class of CSO-gaugings of N=4 supergravity coupled to six vector multiplets. Using the CSO-gaugings we do not find a vacuum that is stable against all scalar perturbations at the point where the matter fields are turned off. However, at this point we do find a stable cosmological scaling solution.

Varghese Mathai

Heat kernels are used in this paper to express the analytic index of projectively invariant Dirac type operators on G-covering spaces of compact manifolds, as elements in the K-theory of certain unconditional completions of the twisted group algebra of G. This is combined with V. Lafforgue's results in the untwisted case, to compute the range of the trace on

Mechthild Huebscher, Patrick Meessen, Tomas Ortin

In this article we complete the classification of the supersymmetric solutions of N=2 D=4 ungauged supergravity coupled to an arbitrary number of vector- and hypermultiplets. We find that in the timelike case the hypermultiplets cause the constant-time hypersurfaces to be curved and have su(2) holonomy identical to that of the hyperscalar manifold. The solut

Peter Bühlmann

We prove that boosting with the squared error loss, $L_2$Boosting, is consistent for very high-dimensional linear models, where the number of predictor variables is allowed to grow essentially as fast as $O$(exp(sample size)), assuming that the true underlying regression function is sparse in terms of the $\ell_1$-norm of the regression coefficients. In the

Klaus Altmann, Juergen Hausen, Hendrik Suess

Generalizing the passage from a fan to a toric variety, we provide a combinatorial approach to construct arbitrary effective torus actions on normal, algebraic varieties. Based on the notion of a ``proper polyhedral divisor'' introduced in earlier work, we develop the concept of a ``divisorial fan'' and show that these objects encode the equivariant gluing o