December 2004 arXiv papers — page 9

Nicolas Mounet, Nicola Marzari

The structural, dynamical, and thermodynamical properties of diamond, graphite and layered derivatives (graphene, rhombohedral graphite) are computed using a combination of density-functional theory (DFT) total-energy calculations and density-functional perturbation theory (DFPT) lattice dynamics at the GGA-PBE level. Overall, very good agreement is found fo

I. V. Stasyuk, O. V. Velychko

A simple four-sublattice order-disorder model is developed for description of phase transitions and dielectric properties of the Rochelle salt crystal. The model is developed as a generalization of the semimicroscopic Mitsui model. The symmetry properties of lattice and spatial orientations of effective dipoles connected with the asymmetric structure units i

P. Melby, F. Vega Reyes, A. Prevost, R. Robertson

We describe a series of experiments and computer simulations on vibrated granular media in a geometry chosen to eliminate gravitationally induced settling. The system consists of a collection of identical spherical particles on a horizontal plate vibrating vertically, with or without a confining lid. Previously reported results are reviewed, including the ob

P. S. Julienne, Y. B. Band, C. J. Williams, M. Trippenbach

We optimize the turning on of a one-dimensional optical potential, V_L(x,t) = S(t) V_0 cos^2(kx) to obtain the optimal turn-on function S(t) so as to load a Bose-Einstein condensate into the ground state of the optical lattice of depth V_0. Specifically, we minimize interband excitations at the end of the turn-on of the optical potential at the final ramp ti

Leticia F. Cugliandolo, Gustavo S. Lozano, Homero Lozza

We study the zero temperature static properties of dissipative ensembles of quantum Ising spins arranged on periodic one dimensional finite clusters and on an infinite chain. The spins interact ferro-magnetically with nearest-neighbour pure and random couplings. They are subject to a transverse field and coupled to an Ohmic bath of quantum harmonic oscillato

J. Velev, R. F. Sabirianov, S. S. Jaswal, E. Y. Tsymbal

Electronic transport in ferromagnetic ballistic conductors is predicted to exhibit ballistic anisotropic magnetoresistance (BAMR) - a change in the ballistic conductance with the direction of magnetization. This phenomenon originates from the effect of the spin-orbit interaction on the electronic band structure which leads to a change in the number of bands

L. J. Singh, Z. H. Barber, A. Kohn, A. K. Petford-Long

Highly (001) oriented thin films of Co2MnSi have been grown on lattice matched GaAs(001) without a buffer layer. Stoichiometric films exhibited a saturation magnetization slightly reduced from the bulk value and films grown at the highest substrate temperature of 689 K showed the lowest resistivity (33 micro.ohm.cm at 4.2 K) and the lowest coercivity (14 Oe)

A. K. M. Newaz, W. Song, Y. Lin, J. Nitta

We have found experimentally that the shot noise in InAlAs-InGaAs-InAlAs Triple-Barrier Resonant-Tunneling Diodes (TBRTD) is reduced over the 2eI Poissonian value whenever their differential conductance is positive, and is enhanced over 2eI when the differential conductance is negative. This behavior, although qualitatively similar to that found in double-ba

Liliana Arrachea, Marcelo J. Rozenberg

Using exact diagonalization techniques we study the dynamical response of the anisotropic disordered Heisenberg model for systems of S=1/2 spins with infinite range random exchange interactions at temperature T=0. The model can be considered as a generalization, to the quantum case, of the well known Sherrington-Kirkpatrick classical spin-glass model. We als

László Gránásy, Tamás Pusztai, György Tegze, James A. Warren

Many structural materials (metal alloys, polymers, minerals, etc.) are formed by quenching liquids into crystalline solids. This highly non-equilibrium process often leads to polycrystalline growth patterns that are broadly termed "spherulites" because of their large-scale average spherical shape. Despite the prevalence and practical importance of sp

S. Carretta, P. Santini, G. Amoretti, M. Affronte

We investigate the role of topology and distortions in the quantum dynamics of magnetic molecules, using a cyclic spin system as reference. We consider three variants of antiferromagnetic molecular ring, i.e. Cr$_8$, Cr$_7$Zn and Cr$_7$Ni, characterized by low lying states with different total spin $S$. We theoretically and experimentally study the low-tempe

M. Bak

The papaer shows how the known, exact results for the two electron bound states can modify the ground state phase diagram of extended Hubbard model (EHM) for on-site attraction, intersite repulsion and arbitrary electron density. The main result is suppression of the superconducting state in favor of normal phase for small charge densities.

T. Masuda, A. Zheludev, B. Roessli, A. Bush

The quasi-one-dimensional helimagnet LiCu2O2 was studied by single crystal inelastic neutron scattering. The dispersion relation of spin wave excitations was measured in the vicinity of the principal magnetic Bragg reflection. A spin wave theoretical analysis of the data yields an estimate of the relevant exchange constants and explains the mechanism of geom

V. I. Zubov

Generalizing the procedures of Girifalco and of Verheijen et al. and using results of the preceding work it has been derived the interaction potential between the molecules of different fullerenes Cn and Cm at orientationally disordered (high-temperature solid and gaseous) phases. We have calculated the coefficients for interactions of the C60 molecule with

X. G. Luo, X. H. Chen, G. Y. Wang, C. H. Wang

Magnetoresistance (MR) of the Bi$_{2-x}$Pb$_x$Sr$_2$Co$_2$O$_y$ ($x$=0, 0.3, 0.4) single crystals is investigated systematically. A nonmonotonic variation of the isothermal in-plane and out-of-plane MR with the field is observed. The out-of-plane MR is positive in high temperatures and increases with decreasing $T$, and exhibits a pronounced hump, and change

P. Zin, J. Chwedenczuk, A. Perez, K. Rzazewski

Mean field approximation treats only coherent aspects of the evolution of a Bose Einstein condensate. However, in many experiments some atoms scatter out of the condensate. We study an analytic model of two counter-propagating atomic Gaussian wavepackets incorporating dynamics of incoherent scattering processes. Within the model we can treat processes of ela

Eduardo Granado, Qingzhen Huang, Jeff W. Lynn, J. Gopalakrishnan

The crystallographic and magnetic properties of La{0.5+delta}A{0.5-delta}Mn{0.5+epsilon}Ru{0.5-epsilon}O{3} (A= Ca, Sr, Ba) were investigated by means of neutron powder diffraction. All studied samples show the orthorhombic perovskite crystal structure, space group Pnma, with regular (Mn,Ru)O{6} octahedra and no chemical ordering of the Mn3+ and Ru4+ ions. F

V. Z. Cerovski, M. Schreiber, U. Grimm

We report results of numerical simulations of wave-packet dynamics in a class of chains consisting of two types of weakly coupled clusters arranged in a quasiperiodic sequence. Properties of eigenstates are investigated using perturbation theory of degenerate levels in the coupling strength v and by numerical diagonalization. Results show that wave packets a

O. A. Aktsipetrov, E. M. Kim, R. V. Kapra, T. V. Murzina

Magnetization-induced optical third-harmonic generation (MTHG) is observed in magnetic nanostructures: Co and Fe nanolayers and granular films containing Co nanoparticles. Magnetization-induced variations of the MTHG characteristics in these nanostructures exceed the typical values of linear magneto-optical Kerr effect by at least an order of magnitude: the

E. Paladino, M. Sassetti, G. Falci

We study the reduced dynamics of a spin (qubit) coupled to a spin-boson environment in the case of pure dephasing. We derive formal exact expressions which can be cast in terms of exact integro-differential master equations. We present results for a SB environment with ohmic dissipation at finite temperatures. For the special value of the ohmic damping stren

Shinji Kawasaki, Guo-qing Zheng, Hiroki Kan, Yoshio Kitaoka

We report on a pressure($P$)-induced evolution of superconductivity and spin correlations in CeIrIn$_5$ via the $^{115}$In nuclear-spin-lattice-relaxation rate measurements. We find that applying pressure suppresses dramatically the antiferromagnetic fluctuations that are strong at ambient pressure. At $P$ = 2.1 GPa, $T_{\rm c}$ increases to $T_{\rm c}$ = 0.

Tsutomu Momoi, Toshiya Hikihara

We discuss duality relations in correlated electronic ladder systems to clarify mutual relations between various conventional and unconventional phases. For the generalized two-leg Hubbard ladder, we find two exact duality relations, and also one asymptotic relation which holds in the low-energy regime. These duality relations show that unconventional (exoti

Marc J. van Veenhuizen, Takaaki Koga, Junsaku Nitta

We investigate the spin-orbit induced spin-interference pattern of ballistic electrons travelling along any regular polygon. It is found that the spin-interference depends strongly on the Rashba and Dresselhaus spin-orbit constants as well as on the sidelength and alignment of the polygon. We derive the analytical formulae for the limiting cases of either ze

A. Honecker, D. C. Cabra, M. D. Grynberg, P. C. W. Holdsworth

We study the ground state and low-lying excitations of the S=1/2 XXZ antiferromagnet on the kagome lattice at magnetization one third of the saturation. An exponential number of non-magnetic states is found below a magnetic gap. The non-magnetic excitations also have a gap above the ground state, but it is much smaller than the magnetic gap. This ground stat

Yoshihiko Nonomura, Xiao Hu

We reply to a recent Comment on our previous article [Phys. Rev. Lett. 86, 5140 (2001)] by Olsson and Teitel [cond-mat/0404473]. We point out that their scaling argument to question the possible vortex slush phase in the frustrated XY model with point defects cannot be sufficiently justified by the provided numerical data, and that their data are indeed cons

Lorenzo Malavasi, Maria Cristina Mozzati, Paolo Ghigna, Gaetano Chiodelli

La1-xCaxMnO3+delta and La1-xNaxMnO3+delta samples with well defined cation molecularity and oxygen contents are analyzed with XRPD, electrical conductivity, electron paramagnetic resonance and static magnetization measurements. Point defects are introduced in the structure by: i) aliovalent cation doping (substitutional defects), ii) oxygen over-stoichiometr

X. H. Chen, C. H. Wang, G. Y. Wang, X. G. Luo

The out-of-plane resistivity ($ρ_c$) and magnetoresistivity (MR) are studied in antiferromangetic (AF) $Nd_{2-x}Ce_xCuO_{4}$ single crystals, which have three types of noncollinear antiferromangetic spin structures. The apparent signatures are observed in $ρ_c(T)$ measured at the zero-field and 14 T at the spin structure transitions, giving a definite eviden

Shinji Watanabe, Masatoshi Imada

Several useful thermodynamic relations are derived for metal-insulator transitions, as generalizations of the Clausius-Clapeyron and Eherenfest theorems. These relations hold in any spatial dimensions and at any temperatures. First, they relate several thermodynamic quantities to the slope of the metal-insulator phase boundary drawn in the plane of the chemi

Stephane Pleutin

We consider free electrons in rectangular quantum dots, with either hard wall boundary conditions or anharmonic confinement. In both cases, due to finite size effects, a homogeneous electric field applied along one of the rectangular axis is shown to induce abrupt changes in the electron density, parallel and perpendicularly to the field direction: the elect

Eric Bertin, Olivier Dauchot, Michel Droz

We study a class of nonequilibrium lattice models which describe local redistributions of a globally conserved energy. A particular subclass can be solved analytically, allowing to define a temperature T_{th} along the same lines as in the equilibrium microcanonical ensemble. The fluctuation-dissipation relation is explicitely found to be linear, but its slo

F. Galliano

I present a simple self-consistent dust spectral energy distribution (SED) model that has been applied to fit the well-sampled observed UV-to-radio SED of four nearby starbursting dwarf galaxies. The main originality of this model is that numerous multi-wavelength observations, from UV to millimeter (mm), constrain in a self-consistent manner, both the local

M. Maturi, M. Meneghetti, M. Bartelmann, K. Dolag

We construct a linear filter optimised for detecting dark-matter halos in weak-lensing data. The filter assumes a mean radial profile of the halo shear pattern and modifies that shape by the noise power spectrum. Aiming at separating dark-matter halos from spurious peaks caused by large-scale structure lensing, we model the noise as being composed of weak le

Martin Pohl

I have studied the variability properties and localization of 3EG J1746-2851 based on EGRET data of the observing periods 1-4. Using corrections for know systematic problems and performing various consistency checks I find no evidence of variability with an amplitude exceeding 30% with the possible exception of viewing period 429, for which a strong soft exc

L. Deharveng, A. Zavagno, J. Caplan

Young massive stars or clusters are often observed at the peripheries of HII regions. What triggers star formation at such locations? Among the scenarios that have been proposed, the `collect and collapse' process is particularly attractive because it permits the formation of massive objects via the fragmentation of the dense shocked layer of neutral gas

Matt J. Jarvis, Caroline van Breukelen, R. J. Wilman

In this letter we report the serendipitous discovery of a genuine type-II quasar at z = 1.65 using integral-field data from VIMOS on the VLT. This is the first discovery of a type-II quasar at z > 1 from optical data alone. J094531-242831, hereafter J0945-2428, exhibits strong narrow (v < 1500km/s) emission lines, has a resolved host galaxy, and is undetecte

M. J. Hardcastle, D. M. Worrall, M. Birkinshaw, R. A. Laing

We have observed the twin-jet radio galaxy 3C296 with Chandra. X-ray emission is detected from the nucleus, from the inner parts of the radio jet, and from a small-scale thermal environment around the jet deceleration region. As we have found in previous observations of other twin-jet radio galaxies, the X-ray jet and a steep pressure gradient in the externa

E. Carretti, G. Bernardi, R. J. Sault, S. Cortiglioni

We analyse the polarized emission at 1.4 GHz in a 3x3 deg^2 area at high Galactic latitude (b ~ -40deg). The region, centred in (RA=5h, Dec=-49deg), was observed with the Australia Telescope Compact Array radio-interferometer, whose 3-30 arcmin angular sensitivity range allows the study of scales appropriate for CMB Polarization (CMBP) investigations. The an

L. V. E. Koopmans

Gravitational lensing and stellar dynamics provide two complementary, nearly orthogonal, constraints on the mass distribution of early-type lens galaxies. This allows the luminous and dark-matter distribution in higher-redshift (z>0.1) galaxies to be studied beyond the limitations of each individual method. Two surveys have been initiated to compile a large

E. N. Vinyajkin, V. A. Razin

Long-term measurements of the radio flux density of Cassiopeia A relative to Cygnus A have been carried out at 927 and 151.5 MHz. It was found the following mean secular decrease rates of the radio emission of Cassiopeia A: $(0.72\pm 0.03)% \hbox{year}^{-1}$ at 927 MHz (for the period 1977--2002) and $(0.88\pm 0.09)% \hbox{year}^{-1}$ at 151.5 MHz (for the p

E. Costantini, J. S. Kaastra, K. C. Steenbrugge, N. Arav

We present the Chandra-LETGS analysis of Mrk 279, a bright Seyfert 1 galaxy. The spectrum shows a variety of features arising from different physical environments in the vicinity of the black hole. We detect three absorption components, located at the redshift of the source. One of them is likely to arise from the host galaxy. An additional component due to

S. Ostapchenko

The new hadronic Monte Carlo model QGSJET-II is applied for extensive air shower (EAS) calculations. The obtained results are compared to the predictions of the original QGSJET and of the SIBYLL 2.1 interaction models. It is shown that non-linear effects change substantially model predictions for hadron-nucleus interactions and produce observable effects for

L. Piro, M. De Pasquale, P. Soffitta, D. Lazzati

In this paper we present BeppoSax and XMM observations of two long Gamma-ray bursts, the X-ray rich event of December 11, 2001 (GRB011211) and the hard and very bright event of November 21, 2001 (GRB011121). In both events we find evidence of a late X-ray burst, taking place several minutes after the prompt emission. The temporal and spectral behaviour of th

M. Tajer, G. Trinchieri, A. Wolter, S. Campana

We have obtained a sample of 143 normal galaxies with X-ray luminosity in the range $10^{38} - 10^{43}$ erg s$^{-1}$ from the cross-correlation of the ROSAT HRI Brera Multi-scale Wavelet (BMW -- HRI) Catalogue with the Lyon-Meudon Extragalactic Database (LEDA). We find that the average X-ray properties of this sample are in good agreement with those of other

J. C. B. Papaloizou

We carry out a general study of the stability of astrophysical flows that appear steady in a uniformly rotating frame. Such a flow might correspond to a stellar pulsation mode or an accretion disk with a free global distortion giving it finite eccentricity. We consider perturbations arbitrarily localized in the neighbourhood of unperturbed fluid streamlines.

G. Pelletier

Black Holes generate a particular kind of environments dominated by an accretion flow which concentrates a magnetic field. The interplay of gravity and magnetism creates this paradoxical situation where relativistic ejection is allowed and consequently high energy phenomena take place. Therefore Black Holes, which are very likely at the origin of powerfull a

Alexander Polishchuk

We prove a new criterion for the homogeneous coordinate ring of a finite set of points in ${\Bbb P}^n$ to be Koszul. Like the well known criterion due to Kempf it involves only incidence conditions on linear spans of subsets of a given set. We also give a sufficient condition for the Koszul property to be preserved when passing to a subset of a finite set of

Andrea V. Maccio&#39;, Fabio Governato, Cathy Horellou

Using N-body simulations of flat, dark energy dominated cosmologies, we show that galaxies around simulated binary systems resembling the Local Group (LG) have low peculiar velocities, in good agreement with observational data. We have compared results for LG-like systems selected from large, high resolution simulations of three cosmologies: a LCDM model, a

R. L. Thews

A brief survey of the role of heavy flavors as a probe of the state of matter produced by high energy heavy ion collisions is presented. Specific examples include energy loss, initial state gluon saturation, thermalization and flow. The formation of quarkonium bound states from interactions in which multiple heavy quark-antiquark pairs are initially produced

P. Giovannangeli, C. P. Korthals Altes

In this paper we provide an exact formula for the area law of the &#39;t Hooft loop for any SU(N) gauge group to cubic order in hot gauge theory. The correction is very small for all temperatures above $T_c$, in stark contrast to the cubic correction to the pressure. The gradient approximation in a previous paper, only valid for large N, is in excellent agre

Stefan Grosskinsky, Tom Hanney

We consider a zero-range process with two species of interacting particles. The steady state phase diagram of this model shows a variety of condensate phases in which a single site contains a finite fraction of all the particles in the system. Starting from a homogeneous initial distribution, we study the coarsening dynamics in each of these condensate phase

Guilherme de Berredo-Peixoto, Ilya L. Shapiro

Higher derivative theory is one of the important models of quantum gravity, renormalizable and asymptotically free within the standard perturbative approach. We consider the $4-ε$ renormalization group for this theory, an approach which proved fruitful in $2-ε$ models. A consistent formulation in dimension $n=4-ε$ requires taking quantum effects of the topol

R. Aloisio, V. S. Berezinsky

We discuss the antiGZK effect in the diffusive propagation of ultra high energy protons in intergalactic magnetic fields, which consists in a jump-like increase of the maximum distance from which ultra high energy protons can reach an observer. The position of this jump, $E_j \approx 2\times 10^{18}$ eV, is determined exclusively by energy losses (transition

Radu Roiban, Marcus Spradlin, Anastasia Volovich

We use the infrared consistency of one-loop amplitudes in N=4 Yang-Mills theory to derive a compact analytic formula for a tree-level NNMHV gluon scattering amplitude in QCD, the first such formula known. We argue that the IR conditions, coupled with recent advances in calculating one-loop box coefficients, can give a new tool for computing tree-level amplit

R. Malara, A. Lima-Santos

We present the classification of the most general regular solutions to the boundary Yang-Baxter equations for vertex models associated with non-exceptional affine Lie algebras. Reduced solutions found by applying a limit procedure to the general solutions are discussed. We also present the list of diagonal $K$-matrices. Special cases are considered separatel

S. C. Chapman, A. W. Blain, Ian Smail, R. J. Ivison

We have obtained spectroscopic redshifts using the Keck-I telescope for a sample of 73 submillimeter (submm) galaxies for which precise positions are available. The galaxies lie at redshifts out to z=3.6, with a median redshift of 2.2. The dust-corrected ultraviolet (UV) luminosities of the galaxies rarely hint at their huge bolometric luminosities indicated

Fabio L. Braghin

Symmetry energy terms from macroscopic mass formulae are investigated as generalized polarizabilities of nuclear matter. Besides the neutron-proton (n-p) symmetry energy the spin dependent symmetry energies and a scalar one are also defined. They depend on the nuclear densities ($ρ$), neutron-proton asymmetry ($b$), temperature ($T$) and exchanged energy and

O. Schroeder, A. Scardicchio, R. L. Jaffe

We study the Casimir energy of a massless scalar field that obeys Dirichlet boundary conditions on a hyperboloid facing a plate. We use the optical approximation including the first six reflections and compare the results with the predictions of the proximity force approximation and the semi-classical method. We also consider finite size effects by contrasti

Gioel Calabrese, David Neilsen

We use the overlapping grids method to construct a fourth order accurate discretization of a first order reduction of the Klein-Gordon scalar field equation on a boosted spinning black hole blackground in axisymmetry. This method allows us to use a spherical outer boundary and excise the singularity from the domain with a spheroidal inner boundary which is m

C. Panagopoulos, M. Majoros, T. Nishizaki, H. Iwasaki

We report detailed bulk magnetization measurements of the normal state in the high transition temperature (high-Tc) superconductor La2-xSrxCuO4. A magnetic order in the form of hysteresis in the low field magnetization was observed at temperatures well above Tc but below the pseudogap temperature. The order arises from the interaction of magnetic domains, an

M. Korzynski, J. Lewandowski, T. Pawlowski

Recently a multidimensional generalization of Isolated Horizon framework has been proposed by Lewandowski and Pawlowski (gr-qc/0410146). Therein the geometric description was easily generalized to higher dimensions and the structure of the constraints induced by the Einstein equations was analyzed. In particular, the geometric version of the zeroth law of th

Igor Zutic, Jaroslav Fabian, Steven C. Erwin

Spin injection and detection in silicon is a difficult problem, in part because the weak spin-orbit coupling and indirect gap preclude using standard optical techniques. We propose two ways to overcome this difficulty, and illustrate their operation by developing a model for spin-polarized transport across a heterojunction. We find that equilibrium spin pola

Fabian Huegging

The contruction of the ATLAS Pixel Detector which is the innermost layer of the ATLAS tracking system is prgressing well. Because the pixel detector will contribute significantly to the ATLAS track and vertex reconstruction. The detector consists of identical sensor-chip-hybrid modules, arranged in three barrels in the centre and three disks on either side f

E. Santopinto

A simple quark-diquark model of baryons with direct and exchange interactions is constructed. Spectrum and form factors are calculated and compared with experimental data. Advantages and disadvantages of the model are discussed.

M. Pavsic

A theory in which 16-dimensional curved Clifford space (C-space) provides a realization of Kaluza-Klein theory is investigated. No extra dimensions of spacetime are needed: &#34;extra dimensions&#34; are in C-space. It is shown that the covariant Dirac equation in C-space contains Yang-Mills fields of the U(1)xSU(2)xSU(3) group as parts of the generalized sp

R. Aurich, S. Lustig, F. Steiner

We analyse the anisotropy of the cosmic microwave background (CMB) for the Poincare dodecahedron which is an example for a multi-connected spherical universe. We compare the temperature correlation function and the angular power spectrum for the Poincare dodecahedral universe with the first-year WMAP data and find that this multi-connected universe can expla

B. P. Holden, A. van der Wel, M. Franx, G. D. Illingworth

Using deep HST ACS imaging and VLT FORS2 spectra, we determined the velocity dispersions, effective radii and surface brightnesses for four early-type galaxies in the $z=1.237$ cluster \cl. All four galaxies are massive, $> 10^{11} M_{\sun}$. These four galaxies, combined with three from \lynx at $z=1.276$, establish the Fundamental Plane of massive early-ty

Roldao da Rocha, Jayme Vaz

Some properties of the Clifford algebras Cl(3,0), Cl(1,3), Cl(1,3)(C), Cl(4,1) and Cl(2,4) are presented, and three isomorphisms between the Dirac-Clifford algebra C x Cl(1,3) and Cl(4,1) are exhibited, in order to construct conformal maps and twistors, using the paravector model of spacetime. The isomorphism between the twistor space inner product isometry

John W. Barrett

This paper explores the idea that within the framework of three-dimensional quantum gravity one can extend the notion of Feynman diagram to include the coupling of the particles in the diagram with quantum gravity. The paper concentrates on the non-trivial part of the gravitational response, which is to the large momenta propagating around a closed loop. By

Jochen Gattnar, Christof Gattringer, Kurt Langfeld, Hugo Reinhardt

We study the interplay between Dirac eigenmodes and center vortices in SU(2) lattice gauge theory. In particular we focus on vortex-removed configurations and compare them to an ensemble of configurations with random changes of the link variables. We show that removing the vortices destroys all zero modes and the near zero modes are no longer coupled to topo

Joerg Fischera, Michael Dopita

We analyse in detail the attenuation caused by an isothermal turbulent distant foreground dust screen. The attenuation curve is well determined by two parameters, the absolute-to-relative attenuation ratio R^A_V=A_V/E(B-V) and the absolute attenuation A_V. We show quantitatively how these two observable quantities depend on the statistical properties of the

F. Benatti, B. C. Hiesmayr, H. Narnhofer

The entanglement-sharing properties of an infinite spin-chain are studied when the state of the chain is a pure, translation-invariant state with a matrix-product structure. We study the entanglement properties of such states by means of their finitely correlated structure. These states are recursively constructed by means of an auxiliary density matrix ρon

Andrew M. Steane

Experimental methods for laser-control of trapped ions have reached sufficient maturity that it is possible to set out in detail a design for a large quantum computer based on such methods, without any major omissions or uncertainties. The main features of such a design are given, with a view to identifying areas for study. The machine is based on 13000 ions

Rudi Cilibrasi, Paul M. B. Vitanyi

Words and phrases acquire meaning from the way they are used in society, from their relative semantics to other words and phrases. For computers the equivalent of `society&#39; is `database,&#39; and the equivalent of `use&#39; is `way to search the database.&#39; We present a new theory of similarity between words and phrases based on information distance a

M. Viel, E. Branchini, R. Cen, J. P. Ostriker

We present a simple method for tracing the spatial distribution and predicting the physical properties of the Warm-Hot Intergalactic Medium (WHIM), from the map of galaxy light in the local universe. Under the assumption that biasing is local and monotonic we map the ~ 2 Mpc/h smoothed density field of galaxy light into the mass density field from which we i

Junjie Cao, Jin Min Yang

In the minimal supersymmetric standard model extended by including right-handed neutrinos with see-saw mechanism, the neutrino Yukaka couplings can be as large as the top-quark Yukawa couplings and thus the neutrino/sneutrino may cause sizable effects in Higgs boson self-energy loops. Our explicit one-loop calculations show that the neutrino/sneutrino effect

Andre Mischke

In this paper, preliminary results are presented on high-$p_T$ inclusive neutral pion measurements in d-Au collisions at $\sqrt{s_{\rm NN}}$ = 200 GeV in the pseudo-rapidity range $0<η<1$. The photons of the decay $pi^0\toγγ$ are detected in the Barrel Electromagnetic Calorimeter of the STAR experiment at RHIC. The analysis of this first BEMC hadron measurem

Houri Ziaeepour

Hadron-hadron interaction and Deep Inelastic Scattering (DIS) at very high energies is dominated by events at small-$x_B$ regime. Interesting and complex physical content of this regime is described by a phenomenological model called McLerran-Venugopalan Color Glass Condensate (MVCGC) model. The advantage of this formalism is the existence of a renormalizati

Prasanta Kumar Das, Kwei-Chou Yang

The recent observations of sizable transverse fractions of B-> phi K* are strongly contrary to the Standard Model expectation. We analyze all possible new-physics four-quark operators. We find that two classes of new-physics operators could offer resolutions to the B-> phi K* polarization anomaly. The (1-γ_5)\otimes (1-γ_5) and σ(1-γ_5)\otimes σ(1-γ_5) opera

Tomoya Ono, Kikuji Hirose

We present a set of efficient techniques in first-principles electronic-structure calculations utilizing the real-space finite-difference method. These techniques greatly reduce the overhead for performing integrals that involve norm-conserving pseudopotentials, solving Poisson equations, and treating models which have specific periodicities, while keeping a

Fernando Dobarro, Bulent Unal

We introduce the concept of a base conformal warped product of two pseudo-Riemannian manifolds. We also define a subclass of this structure called as a special base conformal warped product. After, we explicitly mention many of the relevant fields where metrics of these forms and also considerations about their curvature related properties play important rol

Kirill Krasnov

A known realization of the Lorentz group Racah coefficients is given by an integral of a product of 6 ``propagators&#39;&#39; over 4 copies of the hyperbolic space. These are ``bulk-to-bulk&#39;&#39; propagators in that they are functions of two points in the hyperbolic space. It is known that the bulk-to-bulk propagator can be constructed out of two bulk-to

D. Lust, D. Tsimpis

We derive necessary and sufficient conditions for N=1 compactifications of (massive) IIA supergravity to AdS(4) in the language of SU(3) structures. We find new solutions characterized by constant dilaton and nonzero fluxes for all form fields. All fluxes are given in terms of the geometrical data of the internal compact space. The latter is constrained to b

M. V. S. Bonanca, M. A. M. de Aguiar

We study the energy flow between a one dimensional oscillator and a chaotic system with two degrees of freedom in the weak coupling limit. The oscillator&#39;s observables are averaged over an initially microcanonical ensemble of trajectories of the chaotic system, which plays the role of an environment for the oscillator. We show numerically that the oscill

J. K. Christie, M. Guthrie, C. A. Tulk, C. J. Benmore

The structure of very high-density amorphous (VHDA) ice has been modelled by positionally disordering three crystalline phases, namely ice IV, VI and XII. These phases were chosen because only they are stable or metastable in the region of the ice phase diagram where VHDA ice is formed, and their densities are comparable to that of VHDA ice. An excellent fit

Philippe Blanc, Patrick Delorme

Let G be the group of F-points of a reductive group defined over F, $σ$ a rational involution of this group defined over F and H the group of fixed points of $σ$ . We built rational families of H-fixed vectors in the dual of generalized principal series, using smooth homology of groups. Results of A.G.Helminck,S.P.Wang and A.G.Helminck,G.F.Helminck on the st

L. Alvarez-Ruso, T. Falter, U. Mosel, P. Muehlich

In this review we discuss the observable consequences of in-medium changes of hadronic properties in reactions with elementary probes, and in particular photons, on nuclei. After an outline of the theoretical method used we focus on a discussion of actual observables in photonuclear reactions; we discuss in detail $2π$- and vector-meson production. We show t

Giuseppe D&#39;Appollonio

We review the solution of the boundary CFTs that describe the symmetric branes in the Nappi-Witten gravitational wave, namely D2 and S1 branes. The D2 branes are the twisted branes of the model while the S1 branes are the Cardy branes. We present in both cases the bulk-boundary couplings and the boundary three-point couplings and discuss the relation with br

S. Antoci, D. -E. Liebscher, L. Mihich

The answer to the question, what physical meaning should be attributed to the so-called boost-rotation symmetric exact solutions to the field equations of general relativity, is provided within the general interpretation scheme for the ``theories of relativity&#39;&#39;, based on group theoretical arguments, and set forth by Erich Kretschmann already in the

R. Schaefer, T. Gorin, T. H. Seligman, H. -J. Stoeckmann

The scattering matrix was measured for a flat microwave cavity with classically chaotic dynamics. The system can be perturbed by small changes of the geometry. We define the &#34;scattering fidelity&#34; in terms of parametric correlation functions of scattering matrix elements. In chaotic systems and for weak coupling the scattering fidelity approaches the

Eduardo S. Fraga, G. Krein

We discuss the role of dissipation in the explosive spinodal decomposition scenario of hadron production during the chiral transition after a high-energy heavy ion collision. We use a Langevin description inspired by microscopic nonequilibrium field theory results to perform real-time lattice simulations of the behavior of the chiral fields. We show that the

B. Szilagyi, H-O. Kreiss, J. Winicour

We analyze the excision strategy for simulating black holes. The problem is modeled by the propagation of quasi-linear waves in a 1-dimensional spatial region with timelike outer boundary, spacelike inner boundary and a horizon in between. Proofs of well-posed evolution and boundary algorithms for a second differential order treatment of the system are given

Ghislain Fourier, Peter Littelmann

Let $\Lg$ be a simple complex Lie algebra, we denote by $\Lhg$ the corresponding affine Kac--Moody algebra. Let $Λ_0$ be the additional fundamental weight of $\Lhg$. For a dominant integral $\Lg$--coweight $\lam^\vee$, the Demazure submodule $V_{-\lam^\vee}(m\Lam_0)$ is a $\Lg$--module. For any partition of $\lam^\vee=\sum_j \lam_j^\vee$ as a sum of dominant

Eric Moreau, Olivier Vallée

We present a complete analytical resolution of the one dimensional Burgers equation with the elastic forcing term $-κ^{2} x+f(t)$, $κ\in\mathbb{R}$. Two methods existing for the case $κ=0$ are adapted and generalized using variable and function transformations, valid for all values of space an time. The emergence of a Fokker-Planck equation in the method all

Konstantin Pankrashkin

We prove a variant of Krein&#39;s resolvent formula expressing the resolvents of self-adjoint extensions through the associated boundary conditions. Applications to solvable quantum-mechanical problems are discussed.

H. J. Hilhorst

Let $p\_n$ be the probability for a planar Poisson-Voronoi cell to have exactly $n$ sides. We construct the asymptotic expansion of $\log p\_n$ up to terms that vanish as $n\to\infty$. We show that {\it two independent biased random walks} executed by the polar angle determine the trajectory of the cell perimeter. We find the limit distribution of (i) the an

A. V. Zasov, A. M. Cherepashchuk, L. N. Petrochenko

The relations between masses of Super-Massive Black Holes, Mbh, in galactic nuclei, maximal rotational velocities, Vm, and indicative masses, Mi, of galaxies are studied for galaxies with the available rotation curves. Mbh correlates with both Vm and Mi, although much weaker than with the central velocity dispersion S0. Masses Mbh for early-type galaxies (S0

B. Gonul, N. Celik, E. Olgar

An algebraic non-perturbative approach is proposed for the analytical treatment of Schrödinger equations with a potential that can be expressed in terms of an exactly solvable piece with an additional potential. Avoiding disadvantages of standard approaches, new handy recursion formulae with the same simple form both for ground and excited states have been o

Sakura Schafer-Nameki

The algebraic curve for the psu (2,2|4) quantum spin chain is determined from the thermodynamic limit of the algebraic Bethe ansatz. The Hamiltonian of this spin chain has been identified with the planar 1-loop dilatation operator of N=4 SYM. In the dual AdS_5 x S^5 string theory, various properties of the data defining the curve for the gauge theory are com

B. Gonul, M. Koçak

Within the frame of a novel treatment we make a complete mathematical analysis of exactly solvable one-dimensional quantum systems with non-constant mass, involving their ordering ambiguities. This work extends the results recently reported in the literature and clarifies the relation between physically acceptable effective mass Hamiltonians.

E. Megias, E. Ruiz Arriola, L. L. Salcedo

We describe how the inclusion of the gluonic Polyakov loop incorporates large gauge invariance and drastically modifies finite temperature calculations in chiral quark models after color neutral states are singled out. This generates an effective theory of quarks and Polyakov loops as basic degrees of freedom. We find a strong suppression of finite temperatu