April 2006 arXiv papers — page 16

Francis Heylighen, Paul Cilliers, Carlos Gershenson

The science of complexity is based on a new way of thinking that stands in sharp contrast to the philosophy underlying Newtonian science, which is based on reductionism, determinism, and objective knowledge. This paper reviews the historical development of this new world view, focusing on its philosophical foundations. Determinism was challenged by quantum m

Nuno Santos, Birger Koblitz

Catalog Services play a vital role on Data Grids by allowing users and applications to discover and locate the data needed. On large Data Grids, with hundreds of geographically distributed sites, centralized Catalog Services do not provide the required scalability, performance or fault-tolerance. In this article, we start by presenting and discussing the gen

V. M. Ishchuk, N. A. Spiridonov, V. L. Sobolev

This paper contains results of investigations of inhomogeneous states caused by the coexistence of ferroelectric and antiferroelectric phases in lead-zirconate-titanate based solid solutions. The domains of ferroelectric and antiferroelectric phases with sizes of the order of 20 to 30 nm coexist in the bulk of the samples due to a small difference in the fre

Mladen Georgiev

We consider the formation and stability of the vibronic polaron arising in a degenerate or nearly degenerate electronic system coupled to an appropriate vibrational mode. We define the electron-phonon coupling as a mixing of the electronic states by the phonon mode. Our investigation is similar to that carried out recently by Dennis Clougherty though by intr

Gwenaëlle Félix, Véronique Falk, Umberto D'Ortona

The flow of dry granular material in a half-filled rotating drum is studied. The thickness of the flowing zone is measured for several rotation speeds, drum sizes and beads sizes (size ratio between drum and beads ranging from 47 to 7400). Varying the rotation speed, a scaling law linking mean velocity vs thickness of the flow, $v\sim h^m$, is deduced for ea

M. S. da Luz, C. A. M. dos Santos, M. J. R. Sandim, A. J. S. Machado

We report on the application of the Resistively Shunted Junction (RSJ) model to granular high-TC superconductors. Some derived predictions of the RSJ model are applied to a set of superconducting granular samples which can be considered as a network of Josephson junctions. The investigated samples belong to both hole-doped Y1-xPrxBa2Cu3O7-d (x = 0.0, 0.35, a

Thimo Rohlf, Constantino Tsallis

We numerically study the dynamics of elementary 1D cellular automata (CA), where the binary state $σ_i(t) \in \{0,1\}$ of a cell $i$ does not only depend on the states in its local neighborhood at time $t-1$, but also on the memory of its own past states $σ_i(t-2), σ_i(t-3),...,σ_i(t-τ),...$. We assume that the weight of this memory decays proportionally to

Florian Marquardt

We present a technique for treating many particles moving inside a ballistic interferometer, under the influence of a quantum-mechanical environment (phonons, photons, Nyquist noise etc.). Our approach is based on solving the coupled Heisenberg equations of motion of the many-particle system and the bath and is inspired by the quantum Langevin method known f

C. Lannert, T. -C. Wei, S. Vishveshwara

We explore the physics of three-dimensional shell-shaped condensates, relevant to cold atoms in "bubble traps" and to Mott insulator-superfluid systems in optical lattices. We study the ground state of the condensate wavefunction, spherically-symmetric collective modes, and expansion properties of such a shell using a combination of analytical and nu

Chris J. Pickard, R. J. Needs

It has been suggested that hydrogen may metallise at lower pressures if it is ``precompressed''. Here we introduce a search strategy for predicting high-pressure structures and apply it to silane using first-principles electronic structure computations. It is based on relaxing randomly chosen structures, and is demonstrated to work well for unit cell

F. L. Toninelli

We consider models of directed random polymers interacting with a defect line, which are known to undergo a pinning/depinning (or localization/delocalization) phase transition. We are interested in critical properties and we prove, in particular, finite--size upper bounds on the order parameter (the {\em contact fraction}) in a window around the critical poi

A. W. Sandvik, R. Melko

We report large-scale quantum Monte Carlo calculations at the T=0 antiferromagnetic to valence-bond-solid (VBS) transition of a two-dimensional S=1/2 XY model with four-spin interactions. Finite-size scaling suggests a discontinuous spin stiffness, but a continuous VBS order-parameter. We propose that this is a continuous VBS transition without critical spin

H. Ballhausen, H. Abele, R. S. Eccleston, R. Gaehler

Neutron radiography in many cases is the only non-destructive technique available for the analysis of a wide range of samples from metallurgy, materials engineering and materials testing. In this paper the potential of the technique is illustrated for a transient liquid phase (TLP) joint. TLP bonding produces interface free and stress free joints. The qualit

Stephen D. Wilson, Shiliang Li, H. Woo, Pengcheng Dai

We use high-resolution inelastic neutron scattering to study the low-temperature magnetic excitations of electron-doped superconducting Pr$_{0.88}$LaCe$_{0.12}$CuO$_{4-δ}$ ($T_c=21\pm 1$ K) over a wide energy range (4 meV$\le\hbarω\le 330$ meV). The effect of electron-doping is to cause a wave vector ($Q$) broadening in the low-energy ($\hbarω\le 80$ meV) co

J. Suffczynski, T. Kazimierczuk, M. Goryca, B. Piechal

Systematic measurements of auto- and cross-correlations of photons emitted from individual CdTe/ZnTe quantum dots under pulsed excitation were used to elucidate non-resonant excitation mechanisms in this self-assembled system. Memory effects extending over a few excitation pulses have been detected in agreement with previous reports and quantitatively descri

Nils Sandberg, Mattias Slabanja, Randi Holmestad

A class of proposed coherent precipitate structures (Guinier-Preston zones) in the Al-Mg-Si alloy are investigated using first-principles density functional theory methods. The cluster expansion method is used to extract effective interaction parameters, providing the means for large scale energy calculations of alloy structures. The Mg$_1$Si$_1$ L$1_0$ stru

Somendra M. Bhattacharjee

The observation of duality by Mukherji and Mishra in one dimensional transport problems has been used to develop a general approach to classify and characterize the steady state phase diagrams. The phase diagrams are determined by the zeros of a set of coarse-grained functions without the need of detailed knowledge of microscopic dynamics. In the process, a

B. Kaviraj, S. K. Ghatak

Magneto-impedance (MI) of soft ferromagnetic materials is a sensitive function of the amplitude and frequency of exciting a.c magnetic field. MI (Z) of amorphous ferromagnetic ribbon of nominal composition Fe73.5Nb3 Cu1 Si13.5 B9 is measured at different excitation currents with frequency ranging from 30kHz to 120KHz The excitation (a.c) and biasing (d.c) ma

P. S. Clegg, E. M. Herzig, A. B. Schofield, S. U. Egelhaaf

Using controlled spinodal decomposition, we have created a fluid-bicontinuous structure stabilized by colloidal particles. We present confocal microscopy studies of these structures and their variation with kinetic pathway. Our studies reveal a rigid multilayer of colloidal particles jammed at the interface which prevents the liquids demixing for many hours.

R. Bulla, R. Gutierrez, G. Cuniberti

Measurements of electron transfer rates as well as of charge transport characteristics in DNA produced a number of seemingly contradictory results, ranging from insulating behaviour to the suggestion that DNA is an efficient medium for charge transport. Among other factors, environmental effects appear to play a crucial role in determining the effectivity of

Katja Lindenberg, Santos B. Yuste

We study the reaction front for the process $A+B\to C$ in which the reagents move subdiffusively. We propose a fractional reaction-subdiffusion equation in which both the motion and the reaction terms are affected by the subdiffusive character of the process. Scaling solutions to these equations are presented and compared with those of a direct numerical int

L. Kiknadze, Yu. Mamaladze

The expression is derived for the Magnus force acting on the sphere.

N. V. Antonov, M. Hnatich, J. Honkonen

Stochastic dynamics of a nonconserved scalar order parameter near its critical point, subject to random stirring and mixing, is studied using the field theoretic renormalization group. The stirring and mixing are modelled by a random external Gaussian noise with the correlation function $\proptoδ(t-t') k^{4-d-y}$ and the divergence-free (due to incompres

Yasumasa Hasegawa, Rikio Konno, Hiroki Nakano, Mahito Kohmoto

Tight binding electrons on the honeycomb lattice are studied where nearest neighbor hoppings in the three directions are $t_a,t_b$ and $t_c$, respectively. For the isotropic case, namely for $t_a=t_b=t_c$, two zero modes exist where the energy dispersions at the vanishing points are linear in momentum $k$. Positions of zero modes move in the momentum space a

D. C. E. Bortolotti, S. Ronen, J. L. Bohn, D. Blume

We characterize zero-temperature dipolar Bose gases under external spherical confinement as a function of the dipole strength using the essentially exact many-body diffusion Monte Carlo (DMC) technique. We show that the DMC energies are reproduced accurately within a mean-field framework if the variation of the s-wave scattering length with the dipole streng

Daw-Wei Wang

We develop a strong-coupling theory for the superfluidity of fermion pairing phase in a Bose-Fermi mixture. Dynamical screening, self-energy renormalization, and a pairing gap function are included self-consistently within the adiabatic limit (i.e., the phonon velocity is much smaller than the Fermi velocity). An analytical solution for the transition temper

D. Belitz, T. R. Kirkpatrick, A. Rosch

The nature and effects of the Goldstone mode in the ordered phase of helical or chiral itinerant magnets such as MnSi are investigated theoretically. It is shown that the Goldstone mode, or helimagnon, is a propagating mode with a highly anisotropic dispersion relation, in analogy to the Goldstone mode in chiral liquid crystals. Starting from a microscopic t

Joseph D. MacMillan, Lawrence M. Widrow, Richard N. Henriksen

The radial orbit instability drives dark matter halos toward a universal structure. This conclusion, first noted by Huss, Jain, and Steinmetz, is explored in detail through a series of numerical experiments involving the collapse of an isolated halo into the non-linear regime. The role played by the radial orbit instability in generating the density profile,

Paulo da Costa Moreira

It is proposed a model of Kaluza Klein that does make the quantification of the electric charges without magnetic monopoles. This model of Kaluza Klein allows to calculate de radius of compactation proposed for Klein. The model is of Kaluza Klein, but it has consequences in the theory of the quantum strings, and it is possible to indicate a manner of to test

Todd M. Tripp, Bastien Aracil, David V. Bowen, Edward B. Jenkins

The spectrum of the low-redshift QSO PG0953+415 shows two strong, intervening O VI absorption systems. To study the nature of these absorbers, we have used the Gemini Multiobject Spectrograph to conduct a deep spectroscopic galaxy redshift survey in the 5&#39; x 5&#39; field centered on the QSO. This survey is fully complete for r&#39; < 19.7 and is 73% comp

Caleb A. Scharf

Moons of giant planets may represent an alternative to the classical picture of habitable worlds. They may exist within the circumstellar habitable zone of a parent star, and through tidal energy dissipation they may also offer alternative habitable zones, where stellar insolation plays a secondary, or complementary, role. We investigate the potential extent

J. A. Hinton, G. Hermann, P. Kroetz, S. Funk

During 2003, a camera designed to measure the optical pulsations of pulsars was installed on a telescope of the H.E.S.S. array. The array is designed for gamma-ray astronomy in the ~100 GeV - 100 TeV energy regime. The aims of this exercise were two-fold: to prove the pulsar timing capabilities of H.E.S.S. on all relevant time-scales, and to explore the poss

Joao Magueijo, Rafael D. Sorkin

Using a variety of quantitative implementations of Occam&#39;s razor we examine the low quadrupole, the ``axis of evil&#39;&#39; effect and other detections recently made appealing to the excellent WMAP data. We find that some razors {\it fully} demolish the much lauded claims for departures from scale-invariance. They all reduce to pathetic levels the evide

W. Van Dyke Dixon, Ravi Sankrit, Birgit Otte

We present a survey of diffuse O VI emission in the interstellar medium obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE). Spanning 5.5 years of FUSE observations, from launch through 2004 December, our data set consists of 2925 exposures along 183 sight lines, including all of those with previously-published O VI detections. The data were proc

Eric F. Bell, Marco Barden, Xianzhong Zheng, Casey Papovich

We present a brief discussion of the evolution of disk galaxy stellar masses, sizes, rotation velocities, and star formation rates over the last eight billion years. Recent observations have failed to detect significant evolution in the stellar mass Tully-Fisher relation, stellar mass-size relation, and the stellar mass function of disk galaxies. Yet, most z

M. Machacek, P. E. J. Nulsen, C. Jones, W. R. Forman

We use a 54.4 ks Chandra observation to study nuclear outflow activity in NGC4552 (M89), an elliptical galaxy in the Virgo Cluster. Chandra images in the 0.5-2 keV band show two ring-like features ~1.7 kpc in diameter in the core of NGC4552, as reported previously by Filho et al. We use spherically symmetric point explosion shock models to argue that the sha

Andrea Borch, Klaus Meisenheimer, Eric F. Bell, Hans-Walter Rix

We present an analysis of stellar mass estimates for a sample of 25000 galaxies from the COMBO-17 survey over the interval 0.2<z<1.0. We have developed, implemented, and tested a new method of estimating stellar mass-to-light ratios, which relies on redshift and spectral energy distribution (SED) classification from 5 broadband and 12 medium band filters. We

Simon Johnston, Aris Karastergiou, Kyle Willett

We present polarization data for 32 mainly southern pulsars at 8.4 GHz. The observations show that the polarization fraction is low in most pulsars at this frequency except for the young, energetic pulsars which continue to show polarization fractions in excess of 60 per cent. All the pulsars in the sample show evidence for conal emission with only one third

Krzysztof Bolejko, Charles Hellaby

We develop a non-linear relativistic model of the Shapley Concentration (SC) and its environs, including the Great Attractor (GA) and the Local Group (LG). We take the Shapley concentration as a major attractive centre, and we use the Lemaitre-Tolman model. We constrain our model with present day observations, plus the requirement that it have a physically r

Damien Martin, Andreas Albrecht

We consider two different methods of parameterizing the dark energy equation of state in order to assess possible ``figures of merit&#39;&#39; for evaluating dark energy experiments. The two models are $w(a) = w_0 + (1-a)w_a$ and $w(a) = w_p + (a_p - a)w_a$. This brief note shows that the size of the error contours cannot change under such a reparameterizati

Minho Choi, Klaus W. Hodapp, Masahiko Hayashi, Kentaro Motohara

The NGC 1333 region was observed in the H2 1-0 S(1) line. The H2 images cover a 5&#39; x 7&#39; region around IRAS 4. Numerous H2 emission features were detected. The northeast-southwest bipolar outflow driven by IRAS 4A was studied by combining the H2 images with SiO maps published previously. The SiO-H2 outflows are continuous on the southwestern side but

Joel N. Bregman, Pasquale Temi, Jesse D. Bregman

The mean ages of early-type galaxies obtained from the analysis of optical spectra, give a mean age of 8 Gyr at z = 0, with 40% being younger than 6 Gyr. Independent age determinations are possible by using infrared spectra (5-21 microns), which we have obtained with the Infrared Spectrograph on the Spitzer Observatory. This age indicator is based on the col

Edison Liang, Koichi Noguchi

We review recent developments in particle acceleration by Poynting flux using plasma kinetic simulations, and discuss their potential applications to gamma-ray burst phenomenology

Roelof S. de Jong, Santiago Arribas, Elizabeth Barker, Louis E. Bergeron

We provide an overview of the most important calibration aspects of the NICMOS instrument on board of HST. We describe the performance of the instrument after the installation of the NICMOS Cooling System, and show that the behavior of the instrument has become very stable and predictable. We detail the improvements made to the NICMOS pipeline and outline pl

J. van Leeuwen, J. M. Cordes, D. R. Lorimer, P. C. C. Freire

The recently started Arecibo L-band Feed Array (ALFA) pulsar survey aims to find ~1000 new pulsars. Due to its high time and frequency resolution the survey is especially sensitive to millisecond pulsars, which have the potential to test gravitational theories, detect gravitational waves and probe the neutron-star equation of state. Here we report the result

Roelof S. de Jong, Eric Bell

We investigate the mass-to-light ratios of stellar populations as predicted by stellar population synthesis codes and compare those to dynamical/gravitational measurements. In Bell & de Jong (2001) we showed that population synthesis models predict a tight relation between the color and mass-to-light ratio of a stellar population. The normalization of this r

Yousaf Butt, Nikos Prantzos

We explore the possibility that a now-extinct microquasar may have irradiated the proto-solar neighborhood, causing the &#39;anomalously&#39; high local 11B/10B isotopic ratio. Given the population and typical lifetimes of radio-emitting X-ray binaries, we find the probability of such an event having occurred is not unreasonable. We comment on some tests of

P. Charbonneau, D. R. Reichman

In this Rapid Communication we demonstrate the applicability of an augmented Gibbs ensemble Monte Carlo approach for the phase behavior determination of model colloidal systems with short-ranged depletion attraction and long-ranged repulsion. This technique allows for a quantitative determination of the phase boundaries and ground states in such systems. We

A. M. Soderberg, S. R. Kulkarni, E. Nakar, E. Berger

Over the last decade, long-duration gamma-ray bursts (GRBs) including the subclass of X-ray flashes (XRFs) have been revealed to be a rare variety of Type Ibc supernova (SN). While all these events result from the death of massive stars, the electromagnetic luminosities of GRBs and XRFs exceed those of ordinary Type Ibc SNe by many orders of magnitude. The e

N. L. Homeier, S. Mei, J. P. Blakeslee, M. Postman

We analyse the cluster color-magnitude relation (CMR) for early-type galaxies in two of the richer clusters in the z ~ 0.9 supercluster system to derive average ages and formation redshifts for the early-type galaxy population. Both clusters were observed with the Advanced Camera for Surveys aboard the {\it Hubble Space Telescope} through the F606W and F814W

P. Charbonneau, D. R. Reichman

In this paper we demonstrate the feasibility and utility of an augmented version of the Gibbs ensemble Monte Carlo method for computing the phase behavior of systems with strong, extremely short-ranged attractions. For generic potential shapes, this approach allows for the investigation of narrower attractive widths than those previously reported. Direct com

Ben Weinkove

Let (M, \omega) be a compact symplectic 4-manifold with a compatible almost complex structure J. The problem of finding a J-compatible symplectic form with prescribed volume form is an almost-K\"ahler analogue of Yau's theorem and is connected to a programme in symplectic topology proposed by Donaldson. We call the corresponding equation for the symplectic f

D. Belitz, T. R. Kirkpatrick, A. Rosch

A recent theory for the ordered phase of helical or chiral magnets such as MnSi is used to calculate observable consequences of the helical Goldstone modes or helimagnons. In systems with no quenched disorder, the helimagnon contributions to the specific heat coefficient is shown to have a linear temperature dependence, while the quasi-particle inelastic sca

Hyeonjin Doh, Yong Baek Kim, K. H. Ahn

The nature of the emergent phase near a putative quantum critical point in the bilayer ruthenate Sr$_3$Ru$_2$O$_7$ has been a recent subject of intensive research. It has been suggested that this phase may possess electronic nematic order(ENO). In this work, we investigate the possibility of nematic domain formation in the emergent phase, using a phenomenolo

Sen Zhou, Hong Ding, Ziqiang Wang

A microscopic theory is presented for the observed electronic disorder in superconducting Bi$_2$Sr$_2$CaCu$_2$O$_{8+δ}$. The essential phenomenology is shown to be consistent with the existence of two types of interstitial oxygen dopants: those serving primarily as charge reserviors and those close to the apical plane contributing both carriers and electrost

Nadav Drukker, Shoichi Kawamoto

We study insertions of composite operators into Wilson loops in N=4 supersymmetric Yang-Mills theory in four dimensions. The loops follow a circular or straight path and the composite insertions transform in the adjoint representation of the gauge group. This provides a gauge invariant way to define the correlator of non-singlet operators. Since the basic lo

Jietai Jing, Sheng Feng, Russell Bloomer, Olivier Pfister

We observed continuous-variable entanglement between the bright beams emitted above threshold by an ultrastable optical parametric oscillator, classically phase-locked at a frequency difference of 161.8273240(5) MHz. The amplitude-difference squeezing is -3 dB and the phase-sum one is -1.35 dB. Besides proving entanglement in a new physical system, the phase

Stefan Friedl, Stefano Vidussi

Let N be a closed, oriented 3-manifold. A folklore conjecture states that S^1 x N admits a symplectic structure only if N admits a fibration over the circle. The purpose of this paper is to provide evidence to this conjecture studying suitable twisted Alexander polynomials of N, and showing that their behavior is the same as of those of fibered 3-manifolds.

Ken Hsieh, R. N. Mohapatra, Salah Nasri

We show that in a class of universal extra dimension models (UED), which solves both the neutrino mass and proton decay problem, an admixture of KK photon and KK right handed neutrinos can provide the required amount of cold dark matter (CDM). This model has two parameters $R^{-1}$ and $M_{Z&#39;}$ ($R$ is the radius of the extra space dimensions and $Z&#39;

Victor J. W. Guo, Frederic Jouhet, Jiang Zeng

We present two general finite extensions for each of the two Rogers-Ramanujan identities. Of these one can be derived directly from Watson&#39;s transformation formula by specialization or through Bailey&#39;s method, the second similar formula can be proved either by using the first formula and the q-Gosper algorithm, or through the so-called Bailey lattice

L. M. Jensen, J. Kinnunen, P. Torma

Superconductivity and superfluidity of fermions require, within the BCS theory, matching of the Fermi energies of the two interacting Fermion species. Difference in the number densities of the two species leads either to a normal state, to phase separation, or - potentially - to exotic forms of superfluidity such as FFLO-state, Sarma state or breached pair s

Adilet Imambekov, C. J. Bolech, Mikhail Lukin, Eugene Demler

We consider spin-polarized mixtures of cold fermionic atoms on the BEC side of the Feshbach resonance. We demonstrate that a strongly anisotropic confining potential can give rise to a double-peak structure in the axial distribution of the density difference and a polarization-dependent aspect ratio of the minority species. Both phenomena appear as a result

Alan Forrester

In recent papers, Zurek has objected to the decision-theoretic approach of Deutsch and Wallace to deriving the Born rule for quantum probabilities on the grounds that it courts circularity. Deutsch and Wallace assume that the many worlds theory is true and that decoherence gives rise to a preferred basis. However, decoherence arguments use the reduced densit

Mankei Tsang

Spatial quantum enhancement effects are studied under a unified framework. It is shown that the multiphoton absorption rate of photons with a quantum-enhanced lithographic resolution is reduced, not enhanced, contrary to popular belief. The use of adiabatic soliton expansion is proposed to beat the standard quantum limit on the optical beam displacement accu

Karim A. Malik, David H. Lyth

We study the curvaton scenario using gauge-invariant second order perturbation theory and solving the governing equations numerically. Focusing on large scales we calculate the non-linearity parameter f_nl in the two-fluid curvaton model and compare our results with previous analytical studies employing the sudden decay approximation. We find good agreement

Alberto Accardi

I propose a scaling analysis of the hadron multiplicity ratio measured in Deep Inelastic Scattering on nuclear targets as a tool to distinguish energy loss and nuclear absorption effects on hadron suppression in cold nuclear matter. The proposed scaling variable is a function of the hadron fractional energy and of the virtual photon energy. Its functional fo

Holger Brenner, Almar Kaid

Let K be an algebraically closed field of characteristic zero and let I=(f_1,...,f_n) be a homogeneous R_+-primary ideal in R:=K[X,Y,Z]. If the corresponding syzygy bundle Syz(f_1,...,f_n) on the projective plane is semistable, we show that the Artinian algebra R/I has the Weak Lefschetz property if and only if the syzygy bundle has a special generic splitti

Christian Blohmann, Xiang Tang, Alan Weinstein

Inspired by the group structure on $S^1/ \bbZ$, we introduce a weak hopfish structure on an irrational rotation algebra $A$ of finite Fourier series. We consider a class of simple $A$-modules defined by invertible elements, and we compute the tensor product between these modules defined by the hopfish structure. This class of simple modules turns out to gene

Chuan-Tsung Chan, Jen-Chi Lee, Yi Yang

We study bosonic closed string scattering amplitudes in the high-energy limit. We find that the methods of decoupling of high-energy zero-norm states and the high-energy Virasoro constraints, which were adopted in the previous works to calculate the ratios among high-energy open string scattering amplitudes of different string states, persist for the case of

Jonathan R. Pritchard, Steven R. Furlanetto, Marc Kamionkowski

We examine the effect of inhomogeneous reionization on the galaxy power spectrum and the consequences for probing dark energy. To model feedback during reionization, we apply an ansatz setting the galaxy overdensity proportional to the underlying ionization field. Thus, inhomogeneous reionization may leave an imprint in the galaxy power spectrum. We evolve t

David Berenstein, Diego H. Correa, Samuel E. Vazquez

We systematically study the spectrum of open strings attached to half BPS giant gravitons in the N=4 SYM AdS/CFT setup. We find that some null trajectories along the giant graviton are actually null geodesics of AdS_5x S^5, so that we can study the problem in a plane wave limit setup. We also find the description of these states at weak &#39;t Hooft coupling

F. Baumberger, N. J. C. Ingle, W. Meevasana, K. M. Shen

The electronic structure of the layered 4$d$ transition metal oxide Sr$_{2}$RhO$_{4}$ is investigated by angle resolved photoemission. We find well-defined quasiparticle excitations with a highly anisotropic dispersion, suggesting a quasi-two-dimensional Fermi liquid like ground state. Markedly different from the isostructural Sr$_{2}$RuO$_{4}$, only two ban

M. B. Stone, F. Fernandez-Alonso, D. T. Adroja, N. S. Dalal

We present an inelastic neutron scattering (INS) study of the excitation spectrum of a model S = 1/2 equilateral Heisenberg trimer, Cu_3(O_2C_16H_23)_6.1.2C_6H_12. Earlier measurements were interpreted on the basis of a spin ground state consisting of a pair of degenerate S = 1/2 doublets, with an S = 3/2 quartet excited state. Given that the simplest model

Jirô Akahori

In the present paper, Ito formula and Tanaka formula for a special kind of symmetric random walk in the complex plain are studied. The random walk is called Parisian walk, and its local time is defined to be the number of exit from some regions.

Scott J. Wolk, Norbert Schulz, John Stauffer, Nancy Evans

This paper summarizes contributions and suggestions as presented at the Chandra Workshop Star Formation in the Era of Three Great Observatories conducted in July 2005. One of the declared goals of the workshop was to raise recognition within the star formation research community about the sensible future utilization of the space observatories Spitzer, Hubble

Saeid Azam, Valiollah Shahsanaei

Extended affine Weyl groups are the Weyl groups of extended affine root systems. Finite presentations for extended affine Weyl groups are known only for nullities $\leq 2$, where for nullity 2 there is only one known such presentation. We give a finite presentation for the class of simply laced extended affine Weyl groups. Our presentation is nullity free if

Ulrich Poschinger, Wenzel Salzmann, Roland Wester, Matthias Weidemueller

We investigate pump-dump photoassociation of ultracold molecules with amplitude- and phase-modulated femtosecond laser pulses. For this purpose a perturbative model for the light-matter interaction is developed and combined with a genetic algorithm for adaptive feedback control of the laser pulse shapes. The model is applied to the formation of 85Rb2 molecul

Massimo Cencini, Luigi Palatella, Simone Pigolotti, Angelo Vulpiani

A simplified version of a classical problem in thermodynamics -- the adiabatic piston -- is discussed in the framework of kinetic theory. We consider the limit of gases whose relaxation time is extremely fast so that the gases contained on the left and right chambers of the piston are always in equilibrium (that is the molecules are uniformly distributed and

G. Panotopoulos

In the present work we discuss inflation, dark matter and cosmological evolution in the context of the brane-world scenario. Being string theory inspired, the brane-world models provide corrections to the General Relativity, which is considered to be the low-energy limit of string theory. We find that novel cosmologies are obtained, which potentially can pro

Thomas H. Greif, Volker Bromm

We construct star formation histories at redshifts z > 5 for two physically distinct populations of primordial, metal-free stars, motivated by theoretical and observational arguments that have hinted towards the existence of an intermediate stellar generation between Population III and Population I/II. Taking into account the cosmological parameters as recen

Alejo Martinez-Sansigre, Steve Rawlings, Mark Lacy, Dario Fadda

We discuss the relative merits of mid-infrared and X-ray selection of type-2 quasars. We describe the mid-infrared, near-infrared and radio selection criteria used to find a population of redshift z~2 type-2 quasars which we previously argued suggests that most supermassive black hole growth in the Universe is obscured (Martinez-Sansigre et al., 2005). We pr

Benjamin Doerr, Tobias Friedrich, Christian Klein, Ralf Osbild

We show several ways to round a real matrix to an integer one such that the rounding errors in all rows and columns as well as the whole matrix are less than one. This is a classical problem with applications in many fields, in particular, statistics. We improve earlier solutions of different authors in two ways. For rounding matrices of size $m \times n$, w

Mihaela Vatasescu, Claude M. Dion, Olivier Dulieu

We calculate the rates of formation and detection of ultracold Cs_2 molecules obtained from the photoassociation of ultracold atoms through the double-well 0g- (6S1/2 + 6P3/2) state. We concentrate on two features previously observed experimentally and attributed to tunneling between the two wells [Vatasescu et al 2000 Phys. Rev. A 61 044701]. We show that t

S. Kragset, E. Babaev, A. Sudbo

We perform Monte Carlo studies of vortices in three dimensions in a cylindrical confinement, with uniform and nonuniform density. The former is relevant to rotating 4He, the latter is relevant to a rotating trapped Bose--Einstein condensate. In the former case we find dominant angular thermal vortex fluctuations close to the cylinder wall. For the latter cas

Hsien-Kuei Hwang, Svante Janson

Local limit theorems are derived for the number of occupied urns in general finite and infinite urn models under the minimum condition that the variance tends to infinity. Our results represent an optimal improvement over previous ones for normal approximation.

Bennett Link, Fiorella Burgio

Young, rapidly rotating neutron stars could accelerate ions from their surface to energies of $\sim 1$ PeV. If protons reach such energies, they will produce pions (with low probability) through resonant scattering with x-rays from the stellar surface. The pions subsequently decay to produce muon neutrinos. Here we calculate the energy spectrum of muon neutr

Mark A G Jones, Kyriakos Porfyrakis, G Andrew D Briggs, Robert A Taylor

The endohedral fullerene Er3N@C80 shows characteristic 1.5 micron photoluminescence at cryogenic temperatures associated with radiative relaxation from the crystal-field split Er3+ 4I13/2 manifold to the 4I15/2 manifold. Previous observations of this luminescence were carried out by photoexcitation of the fullerene cage states leading to relaxation via the i

Raul Donangelo, Mogens H. Jensen, Ingve Simonsen, Kim Sneppen

The waiting time needed for a stock market index to undergo a given percentage change in its value is found to have an up-down asymmetry, which, surprisingly, is not observed for the individual stocks composing that index. To explain this, we introduce a market model consisting of randomly fluctuating stocks that occasionally synchronize their short term dra

Rabah Souam, Eric Toubiana

We discuss existence and classification of totally umbilic surfaces in the model geometries of Thurston and the Berger spheres. We classify such surfaces in $H^2 \times R$, $S^2 \times R$ and the Sol group. We prove nonexistence in the Berger spheres and in the remaining model geometries other than the space forms.

Adrian Dumitru, Yasushi Nara, Michael Strickland

We present solutions of coupled particle-field evolution in classical U(1) and SU(2) gauge theories in real time on three-dimensional lattices. For strongly anisotropic particle momentum distributions, we find qualitatively different behavior for the two theories when the field strength is high enough that non-Abelian self-interactions matter for SU(2). It a

J. Gonzalez-Nuevo, F. Argueso, M. Lopez-Caniego, L. Toffolatti

We propose a new detection technique in the plane based on an isotropic wavelet family. This family is naturally constructed as an extension of the Gaussian-Mexican Hat Wavelet pair and for that reason we call it the Mexican Hat Wavelet Family (MHWF). We show the performance of these wavelets when dealing with the detection of extragalactic point sources in

Pierre-Henri Chavanis

We present a kinetic theory for inhomogeneous systems with weak long-range interactions. Starting from the Klimontovich equation and using a quasilinear theory, we obtain a closed kinetic equation describing the relaxation of the distribution function of the system as a whole due to resonances between different orbits. This equation is written in angle-actio

N. M. Bogoliubov, C. Malyshev

A quantum field-theoretical model which describes spatially non-homogeneous one-dimensional non-relativistic repulsive Bose gas in an external harmonic potential is considered. We calculate the two-point thermal correlation function of the Bose gas in the framework of the functional integration approach. The calculations are done in the coordinate representa

Per Olof Hulth

The success of the AMANDA neutrino telescope has shown that the ice sheet at the geographical South Pole is a suitable medium for optical Cherenkov detection of high energy neutrino interactions. Several thousands of atmospheric neutrinos have been recorded by AMANDA and the sensitivity for cosmic neutrinos has continuously improved. So far no cosmic neutrin

A. N. Schellekens

This is a translation of an inaugural speech given originally in Dutch in 1998. The topic of that speech, intended for a general audience, was what is now called &#34;The Anthropic Landscape of String Theory&#34;.

R. N. Mohan, Moon Ho Lee, Subhash Pokrel

By making use of the generalized concept of orthogonality in Latin squares, certain t-partite graphs have been constructed and a suggestion for a net work system and some applications have been made.

Chanyoung Sung

We consider the equivariant Yamabe problem, i.e. the Yamabe problem on the space of G-invariant metrics for a compact Lie group G. The G-Yamabe invariant is analogously defined as the supremum of the constant scalar curvatures of unit volume G-invariant metrics minimizing the total scalar curvature functional in their G-invariant conformal subclasses. We pro

S. E. Ahnert, D. Garlaschelli, T. M. Fink, G. Caldarelli

We present a new approach to the calculation of measures in weighted networks, based on the translation of a weighted network into an ensemble of edges. This leads to a straightforward generalization of any measure defined on unweighted networks, such as the average degree of the nearest neighbours, the clustering coefficient, the `betweenness&#39;, the dist

Sophie Chemla

In this article, $X$ will denote a ${\cal C}^{\infty}$ manifold. In a very famous article, Kontsevich showed that the differential graded Lie algebra (DGLA) of polydifferential operators on $X$ is formal. Calaque extended this theorem to any Lie algebroid. More precisely, given any Lie algebroid $E$ over $X$, he defined the DGLA of $E$-polydifferential opera

S. Heinemeyer, W. Hollik, D. Stockinger, A. M. Weber

We present the currently most accurate evaluation of the W boson mass, M_W, in the Minimal Supersymmetric Standard Model (MSSM). The full complex phase dependence at the one-loop level, all available MSSM two-loop corrections as well as the full Standard Model result have been included. We analyse the impact of the different sectors of the MSSM at the one-lo