September 2006 arXiv papers — page 20

K. Feitosa, Olivia L. Halt, Randall D. Kamien, D. J. Durian

We measure the liquid content, the bubble speeds, and the distribution of bubble sizes, in a vertical column of aqueous foam maintained in steady-state by continuous bubbling of gas into a surfactant solution. Nearly round bubbles accumulate at the solution/foam interface, and subsequently rise with constant speed. Upon moving up the column, they become larg

Jan Vorberger, I. Tamblyn, B. Militzer, S. A. Bonev

Equilibrium properties of hydrogen-helium mixtures under conditions similar to the interior of giant gas planets are studied by means of first principle density functional molecular dynamics simulations. We investigate the molecular and atomic fluid phase of hydrogen with and without the presence of helium for densities between $ρ=0.19$ g$ $cm$^{-3}$ and $ρ=

B. Sun, W. X. Zhang, S. Yi, M. S. Chapman

We show that atomic dipolar effects are detectable in the system that recently demonstrated two-atom coherent spin dynamics within individual lattice sites of a Mott state. Based on a two-state approximation for the two-atom internal states and relying on a variational approach, we have estimated the spin dipolar effect. Despite the absolute weakness of the

A. Y. Abul-Magd

The joint eigenvalue distributions of random-matrix ensembles are derived by applying the principle maximum entropy to the Renyi, Abe and Kaniadakis entropies. While the Renyi entropy produces essentially the same matrix-element distributions as the previously obtained expression by using the Tsallis entropy, and the Abe entropy does not lead to a closed for

G. V. Astakhov, A. V. Koudinov, K. V. Kavokin, I. S. Gagis

We study exciton spin decay in the regime of strong electron-hole exchange interaction. In this regime the electron spin precession is restricted within a sector formed by the external magnetic field and the effective exchange fields triggered by random spin flips of the hole. Using Hanle effect measurements, we demonstrate that this mechanism dominates our

Nic Shannon, Hiroaki Ueda, Yukitoshi Motome, Karlo Penc

Magnetization plateaux, visible as anomalies in magnetic susceptibility at low temperatures, are one of the hallmarks of frustrated magnetism. An extremely robust half-magnetization plateau is observed in the spinel oxides CdCr2O4 and HgCr2O4, where it is accompanied by a substantial lattice distortion. We give an overview of the present state experiment for

Marius Costeniuc, Richard S. Ellis, Peter Tak-Hun Otto

We derive probabilistic limit theorems that reveal the intricate structure of the phase transitions in a mean-field version of the Blume-Emery-Griffiths model. These probabilistic limit theorems consist of scaling limits for the total spin and moderate deviation principles (MDPs) for the total spin. The model under study is defined by a probability distribut

Isabelle Cantat, Olivier Pitois

We present experimental results on the Stokes experiment performed in a 3D dry liquid foam. The system is used as a rheometric tool : from the force exerted on a 1cm glass bead, plunged at controlled velocity in the foam in a quasi static regime, local foam properties are probed around the sphere. With this original and simple technique, we show the possibil

Emmanuel Terriac, Janine Etrillard, Isabelle Cantat

We study experimentally the pressure drop needed to push a bubble train in a millimetric channel, as a function of the velocity. For dry liquid foams, the influence of the amount of liquid and of the bubble size is pointed out and we predict theoretically that this influence is closely related to the power law obtained for the force/velocity relation. This m

Isabelle Cantat, Olivier Pitois

The paper reports on the quasi-static steady flow of a dry liquid foam around a fixed spherical bead, few times larger than the typical bubble size. The force exerted on the bead is recorded with a precision and a time resolution large enough to show the succession of elastic loading of the foam, separated by sudden force drops. The foam structure is observe

M. Eckstein, M. Kollar, D. Vollhardt

We investigate the properties of the spectral function A(omega,U) of correlated electrons within the Hubbard model and dynamical mean-field theory. Curves of A(omega,U) vs. omega for different values of the interaction U are found to intersect near the band-edges of the non-interacting system. For a wide range of U the crossing points are located within a sh

A. Pfund, I. Shorubalko, R. Leturcq, K. Ensslin

We present low temperature transport measurements on double quantum dots in InAs nanowires grown by metal-organic vapor phase epitaxy. Two dots in series are created by lithographically defined top-gates with a procedure involving no extra insulating layer. We demonstrate the full tunability from strong to weak coupling between the dots. The quantum mechanic

I. Shorubalko, A. Pfund, R. Leturcq, M. T. Borgström

Quantum dots realized in InAs are versatile systems to study the effect of spin-orbit interaction on the spin coherence, as well as the possibility to manipulate single spins using an electric field. We present transport measurements on quantum dots realized in InAs nanowires. Lithographically defined top-gates are used to locally deplete the nanowire and to

Ganpathy Murthy, R. Shankar

We consider small ballistic quantum dots weakly coupled to the leads in the chaotic regime and look for significant spin-orbit effects. We find that these effects can become quite prominent in the vicinity of degeneracies of many-body energies. We illustrate the idea by considering a case where the intrinsic exchange term -JS^2 brings singlet and triplet man

D. K. Christopoulos, A. F. Terzis, A. G. Vanakaras, D. J. Photinos

We present a molecular simulation study of the structure of linear dendronized polymers. We use excluded volume interactions in the context of a generic coarse-grained molecular model whose geometrical parameters are tuned to represent a poly(para-phenylene) backbone with benzyl ether, Frechet type dendrons. We apply Monte Carlo sampling in order to investig

K. Rytkönen, J. Akola, M. Manninen

Alkali metal atoms (Li, Na, K, Rb, Cs), dimers and (2$\times$2) monolayers on a graphite (0001) surface have been studied using density functional theory, pseudopotentials, and a periodic substrate. The adatoms bind at the hollow site (graphite hexagon), with Li lying closest to (1.84 Å) and Cs farthest (3.75 Å) from the surface. The adsorption energies rang

P. Lucignano, B. Jouault, A. Tagliacozzo

Spin-orbit interaction in a quantum dot couples far infrared radiation to non center of mass excitation modes, even for parabolic confinement and dipole approximation. The intensities of the absorption peaks satisfy the optical sum rule, giving direct information on the total number of electrons inside the dot. In the case of a circularly polarized radiation

F. Mila, F. Vernay, A. Ralko, F. Becca

We discuss how orbital degeneracy, which is usually removed by a cooperative Jahn-Teller distortion, could under appropriate circumstances lead rather to a Resonating Valence Bond spin-orbital liquid. The key points are: i) The tendency to form spin-orbital dimers, a tendency already identified in several cases; ii) The mapping onto Quantum Dimer Models, whi

Shu-Chiuan Chang, Lung-Chi Chen

We obtain the numbers of spanning trees on the Sierpinski gasket $SG_d(n)$ with dimension $d$ equal to two, three and four. The general expression for the number of spanning trees on $SG_d(n)$ with arbitrary $d$ is conjectured. The numbers of spanning trees on the generalized Sierpinski gasket $SG_{d,b}(n)$ with $d=2$ and $b=3,4$ are also obtained.

R. Sopracase, G. Gruener, C. Autret-Lambert, V. Ta Phuoc

The optical conductivity of the undoped PrMnO$_3$ manganite has been investigated in details at various temperatures between 300 and 4 K. Its low energy spectrum exhibits an optical gap, and is characterized by a single broad peak centered at $\sim$ 2 eV. This peak is interpreted in terms of an indirect interband transition between the split bands $e_\text{g

Ion I. Cotaescu, Paul Gravila, Marius Paulescu

One propose a relativistic version of the transfer matrix method for an electron moving through a given number of rectangular barriers of arbitrary shape. It is shown that starting with the Dirac equation depending on the effective mass and a suitably chosen relativistic potential, one obtains a relativistic transfer matrix which takes the correct traditiona

Evzen Subrt, Petr Chvosta

We study the one-dimensional diffusion process which takes place between two reflecting boundaries and which is acted upon by a time-dependent and spatially-constant force. The assumed force possesses both the harmonically oscillating and the constant component. Using techniques presented in the paper [1] we derive the set of integral equations whose compris

Ken Kamrin, Martin Z. Bazant

There have been many attempts to derive continuum models for dense granular flow, but a general theory is still lacking. Here, we start with Mohr-Coulomb plasticity for quasi-2D granular materials to calculate (average) stresses and slip planes, but we propose a "stochastic flow rule" (SFR) to replace the principle of coaxiality in classical plastici

A. A Snarskii, G. V. Adzhigai, I. V. Bezsudnov

The paper introduces and analyzes a new characteristic of thermoelectric composites - their intrinsic figure of merit characterizing the influence of thermoelectric phenomena on the effective properties of composites and governing thermal into electric energy conversion within a composite.

Ken'ichi Takano

We study a quantum spin system on a honeycomb lattice, when it includes frustration and distortion in antiferromagnetic (AF) exchange interactions. We transform the spin system onto a nonlinear sigma model (NLSM) in a new way preserving the original spin degrees of freedom. Assisted by a renormalization- group argument, the NLSM provides a ground-state phase

N. Fukushima, Y. Ohashi, E. Taylor, A. Griffin

The superfluid density is a fundamental quantity describing the response to a rotation as well as in two-fluid collisional hydrodynamics. We present extensive calculations of the superfluid density ρ_s in the BCS-BEC crossover regime of a uniform superfluid Fermi gas at finite temperatures. We include strong-coupling or fluctuation effects on these quantitie

H. Yaguchi, K. Takizawa, M. Kawamura, N. Kikugawa

We have investigated the tunnelling properties of the interface between superconducting Sr2RuO4 and a single Ru inclusion in eutectic. By using a micro-fabrication technique, we have made Sr2RuO4/Ru junctions on the eutectic system that consists of Sr2RuO4 and Ru micro-inclusions. Such a eutectic system exhibits surface superconductivity, called the 3-K phas

John W. Lawson, Charles W. Bauschlicher

Ab initio calculations of phenyl dithiol connected to Au, Ag, Pd, and Pt electrodes are performed using non-equilibrium Green's functions and density functional theory. For each metal, the properties of the molecular junction are considered both in equilibrium and under bias. In particular, we consider in detail charge transfer, changes in the electrosta

Alexei Kitaev

We propose a qubit implementation based on exciton condensation in capacitively coupled Josephson junction chains. The qubit is protected in the sense that all unwanted terms in its effective Hamiltonian are exponentially suppressed as the chain length increases. We also describe an implementation of a universal set of quantum gates. Most gates also offer ex

Hari P Dahal, Yogesh N. Joglekar, Kevin S. Bedell, Alexander V. Balatsky

Graphene, a single sheet of graphite, has attracted tremendous attention due to recent experiments which demonstrate that carriers in it are described by massless fermions with linear dispersion. In this note, we consider the possibility of Wigner crystallization in graphene in the absence of external magnetic field. We show that the ratio of potential and k

W. Yi, L. -M. Duan

We derive a set of dynamical mean-field equations for strongly interacting fermionic atoms in a potential trap across a Feshbach resonance. Our derivation is based on a variational ansatz, which generalizes the crossover wavefunction to the inhomogeneous case, and the assumption that the order parameter is slowly varying over the size of the Cooper pairs. Th

K. Borkje, A. Sudbo

The paper has been withdrawn

E. S. Levine, Leo Blitz, Carl Heiles, Martin Weinberg

We examine the outer Galactic HI disk for deviations from the b=0 plane by constructing maps of disk surface density, mean height, and thickness. We find that the Galactic warp is well described by a vertical offset plus two Fourier modes of frequency 1 and 2, all of which grow with Galactocentric radius. A perturbation theory calculation demonstrates that t

A. Gruzinov, M. Kleban, M. Porrati, M. Redi

The non-linearity of Einstein's equations makes it possible for small-scale matter inhomogeneities to affect the Universe at cosmological distances. We study the size of such effects using a simple heuristic model that captures the most important backreaction effect due to nonrelativistc matter, as well as several exact solutions describing inhomogeneous

R. F. Peletier, K. Fathi, E. L. Allard, J. H. Knapen

We give two examples of spiral galaxies that show non-circular gas motions in the inner kiloparsecs, from SAURON integral field spectroscopy. We use harmonic decomposition of the velocity field of the ionized gas to study the underlying mass distribution, employing linear theory. The higher order harmonic terms and the main kinematic features of the observed

Trevor A. Miles, Somak Raychaudhury, Paul A. Russell

We present J and K-band luminosity functions (LF) for the Group Evolution Multiwavelength Study (GEMS) sample of 60 nearby groups of galaxies, with photometry from the 2MASS survey. We find that, as seen in B and R-band photometry of a subsample of these groups in our earlier work, the LFs of the X-ray dim groups (L_X < 10^41.7 erg/s) show a depletion of gal

Stijn Wuyts, Ivo Labbe, Marijn Franx, Gregory Rudnick

We analyze very deep HST, VLT and Spitzer photometry of galaxies at 2<z<3.5 in the Hubble Deep Field South. The sample is selected from the deepest public K-band imaging currently available. We show that the rest-frame U-V vs V-J color-color diagram is a powerful diagnostic of the stellar populations of distant galaxies. Galaxies with red rest-frame U-V colo

A. Kogut, D. T. Chuss, D. Fixsen, G. F. Hinshaw

The Primordial Anisotropy Polarization Pathfinder Array (PAPPA) is a balloon-based instrument to measure the polarization of the cosmic microwave background and search for the signal from gravity waves excited during an inflationary epoch in the early universe. PAPPA will survey a 20 x 20 deg patch at the North Celestial Pole using 32 pixels in 3 passbands c

Alexei O. Razoumov, Jesper Sommer-Larsen

Using results from high-resolution galaxy formation simulations in a standard Lambda-CDM cosmology and a fully conservative multi-resolution radiative transfer code around point sources, we compute the energy-dependent escape fraction of ionizing photons from a large number of star forming regions in two galaxies at five different redshifts from z=3.8 to 2.3

Randall B. Wayth, Rachel L. Webster

We have developed a new software tool, Lensview, for modelling resolved gravitational lens images. Based on the LensMEM algorithm, the software finds the best fitting lens mass model and source brightness distribution using a maximum entropy constraint. The method can be used with any point spread function or lens model. We review the algorithm and introduce

Joel R. Primack

After briefly reviewing the good agreement between large-scale observations and the predictions of the now-standard CDM theory and problems with the MOND alternative, I summarize several of the main areas of possible disagreement between theory and observation: galaxy centers, dark matter substructure, angular momentum, and the sequence of cosmogony, updatin

Daniel Kasen, S. E. Woosley

Brighter Type Ia supernovae (SNe Ia) have broader, more slowly declining B-band light curves than dimmer SNe Ia. We study the physical origin of this width-luminosity relation (WLR) using detailed radiative transfer calculations of Chandrasekhar mass SN Ia models. We find that the luminosity dependence of the diffusion time (emphasized in previous studies) i

Nino Panagia, Guido De Marchi, Martino Romaniello

We present the first results of our study of stellar populations in the Large and Small Magellanic Clouds based on multiband WFPC2 observations of "random" fields taken as part of the "pure parallel" program carried out by the Space Telescope Science Institute as a service to the community.

I. Jimenez-Serra, J. Martin-Pintado, S. Viti, S. Martin

Magnetic precursors of C-shocks accelerate, compress and heat molecular ions, modifying the kinematics and the physical conditions of the ion fluid with respect to the neutral one. Electron densities are also expected to be significantly enhanced in shock precursors. In this Letter, we present observations of strongly polar ion and neutral molecules such as

R. J. H. Dunn, A. C. Fabian

We analyse those objects in the Brightest 55 sample of clusters of galaxies which have a short central cooling time and a central temperature drop. Such clusters are likely to require some form of heating. Where clear radio bubbles are observed in these clusters, their energy injection is compared to the X-ray cooling rate. Of the 20 clusters requiring heati

C. Foellmi

GRO J1655--40 is a galactic microquasar, i.e. a short-period binary with relativistic radio-jets and where the companion is a black-hole. A little after its discovery in 1994 by $BATSE$, a distance of 3.2$\pm$0.2 kpc has been estimated, and at which the radio jets appeared superluminal. Since that time, this distance of GRO J1655--40 has been discussed in ma

Thomas E. Harrison, Steve B. Howell, Paula Szkody, France A. Cordova

We have used NIRSPEC on Keck II to obtain $K$-band spectroscopy of the low mass X-ray binary V616 Mon (= A0620$-$00). V616 Mon is the proto-typical soft x-ray transient containing a black hole primary. As such it is important to constrain the masses of the binary components. The modeling of the infrared observations of ellipsoidal variations in this system l

A. Achterberg et al.

The sensitivity of a search for sources of TeV neutrinos can be improved by grouping potential sources together into generic classes in a procedure that is known as source stacking. In this paper, we define catalogs of Active Galactic Nuclei (AGN) and use them to perform a source stacking analysis. The grouping of AGN into classes is done in two steps: first

Jonathan W. Keohane, William T. Reach, Jeonghee Rho, Thomas H. Jarrett

We present near-infrared narrow-band images of the supernova remnant W49B, taken with the WIRC instrument on the Hale 200 inch telescope on Mt. Palomar. The 1.64 micron [Fe II] image reveals a barrel-shaped structure with coaxial rings, which is suggestive of bipolar wind structures surrounding massive stars. The 2.12 micron shocked molecular hydrogen image

N. Lodieu, N. C. Hambly, R. F. Jameson

We present the results of a 9.3 square degree infrared (ZYJHK) survey in the Upper Scorpius association extracted from the UKIRT Infrared Deep Sky Survey (UKIDSS) Galactic Cluster Survey Early Data Release. We have selected a total of 112 candidates from the ($Z-J$,$Z$) colour-magnitude diagram over the Z=12.5-20.5 magnitude range, corresponding to M = 0.25-

Loic Chevallier, Joachim Pelkowski, Bernard Rutily

An exact model is proposed for a gray, isotropically scattering planetary atmosphere in radiative equilibrium. The slab is illuminated on one side by a collimated beam and is bounded on the other side by an emitting and partially reflecting ground. We provide expressions for the incident and reflected fluxes on both boundary surfaces, as well as the temperat

Sara L. Ellison

Although damped Lyman alpha (DLA) systems are usually considered metal-poor, it has been suggested that this could be due to observational bias against metal-enriched absorbers. I review recent surveys to quantify the particular issue of dust obscuration bias and demonstrate that there is currently no compelling observational evidence to support a widespread

Chris Simpson, Alejo Martinez-Sansigre, Steve Rawlings, Rob Ivison

We describe deep radio imaging at 1.4-GHz of the 1.3 square degree Subaru/XMM-Newton Deep Field (SXDF), made with the Very Large Array in B and C configurations. We present a radio map of the entire field, and a catalogue of 505 sources covering 0.8 square degrees to a peak flux density limit of 100 microJy. Robust optical identifications are provided for 90

L. Mashonkina, A. J. Korn, N. Przybilla

Non-local thermodynamical equilibrium (NLTE) line formation for neutral and singly-ionized calcium is considered through a range of spectral types when the Ca abundance varies from the solar value down to [Ca/H] = -5. Departures from LTE significantly affect the profiles of Ca I lines over the whole range of stellar parameters considered. However, at [Ca/H]

Uriel Giveon, Matthew J. Richter, Robert H. Becker, Richard L. White

We present data from mid-infrared Keck Telescope imaging of 18 radio-selected ultra-compact HII region candidates at diffraction-limited resolution. The goal of these observations is to determine the sizes, luminosities, and morphologies of the mid-infrared emitting dust surrounding the stellar sources. All 18 sources were imaged at 11.7um and at 17.65um, an

Katia Biazzo, Antonio Frasca, Gregory W. Henry, Santo Catalano

We present a photometric and spectroscopic study of four G-K dwarfs, namely HD 166, epsilon Eri, chi1 Ori and kappa1 Cet. In three cases, we find a clear spatial association between photospheric and chromospheric active regions. For chi1 Ori we do not find appreciable variations of photospheric temperature, and chromospheric Halpha emission. We applied a spo

M. Haywood

I review the uncertainties in two observational constraints of the Galactic disc chemical evolution: the metallicity distribution (MD) of long-lived dwarfs and the age-metallicity relation (AMR). It is shown first that the observed MD, designed with standard methods, is more fit to a closed-box model than to the infall MD. We argue that this is due to the sp

Giovanni Miniutti, Andrew C. Fabian, Naohisa Anabuki, Jamie Crummy

Suzaku has, for the first time, enabled the hard X-ray variability of the Seyfert 1 galaxy MCG-6-30-15 to be measured. The variability in the 14-45 keV band, which is dominated by a strong reflection hump, is quenched relative to that at a few keV. This directly demonstrates that the whole reflection spectrum is much less variable than the power-law continuu

M. Guedel, D. L. Padgett, C. Dougados

(abridged:) The Taurus Molecular Cloud (TMC) contains numerous prototypical examples of deeply embedded protostars with massive disks and outflows, classical and weak-lined T Tauri stars, jets and Herbig-Haro objects, and a growing number of confirmed brown dwarfs. Star formation is ongoing, and the cloud covers all stages of pre-main sequence stellar evolut

S. Pfalzner, C. Olczak

AIM:The aim of this work is to understand to what extend gravitational interactions between the stars in high-density young stellar clusters, like the Orion Nebula Cluster (ONC), change the angular momentum in their protoplanetary discs. METHOD:Two types of simulations were combined -- N-body simulations of the dynamics of the stars in the ONC, and angular m

V. I. Shishov, W. A. Coles, B. J. Rickett, M. K. Bird

Topics of the Colloquium: a) Interplanetary scintillation b) Interstellar scintillation c) Modeling and physical origin of the interplanetary and the interstellar plasma turbulence d) Scintillation as a tool for investigation of radio sources e) Seeing through interplanetary and interstellar turbulent media Ppt-presentations are available on the Web-site: ht

Stephen L. W. McMillan, Enrico Vesperini, Simon F. Portegies Zwart

Some young star clusters show a degree of mass segregation that is inconsistent with the effects of standard two-body relaxation from an initially unsegregated system without substructure, in virial equilibrium, and it is unclear whether current cluster formation models can account for this degree of initial segregation in clusters of significant mass. In th

M. Lopez-Corredoira, C. M. Gutierrez

AIMS. To check whether the polar angle distribution of QSOs around nearby spiral galaxies is isotropic or not. METHODS. A statistical analysis of the polar angle distribution of large samples of QSOs from the SDSS survey and Monte Carlo simulations to calculate their significance are carried out. RESULTS. There is a clear excess of QSOs near the minor axis w

W. L. F. Marcolino, D. J. Hillier, F. X. de Araujo, C. B. Pereira

We present far-UV to optical analyses of four hydrogen deficient central stars of planetary nebulae: BD+303639, NGC 40, NGC 5315 and NGC 6905. Using the radiative transfer code CMFGEN, we determined new physical parameters and chemical abundances for these stars. The results were analyzed in the context of the [WR] => PG 1159 evolution via the transformed ra

Alexandra S. Landsman, Ira B. Schwartz

Complete chaotic synchronization of end lasers has been observed in a line of mutually coupled, time-delayed system of three lasers, with no direct communication between the end lasers. The present paper uses ideas from generalized synchronization to explain the complete synchronization in the presence of long coupling delays, applied to a model of mutually

Jason Alicea, Matthew P. A. Fisher

Although magnetically ordered at low temperatures, the spin-1/2 triangular antiferromagnet Cs_2CuCl_4 exhibits remarkable spin dynamics that strongly suggest proximity to a spin liquid phase. Here we address the question of whether a proximate spin liquid may also occur in an applied magnetic field, leaving a similar imprint on the dynamical spin correlation

T. C. Ralph, G. J. Milburn, T. Downes

We propose an experiment in which an entangled pair of optical pulses are propagated through non-uniform gravitational fields. A field operator calculation of this situation predicts decoherence of the optical entanglement under experimentally realistic conditions.

Gustavo Burdman, Alex Gomes Dias

In the standard model in universal extra dimensions (UED) the mass of the Higgs field is driven to the cutoff of the higher-dimensional theory. This re-introduces a small hierarchy since the compactification scale 1/R should not be smaller than the weak scale. In this paper we study possible solutions to this problem by considering five-dimensional theories

Aleksey M. Tikhonov

The forces of electrical imaging strongly polarize the surface of colloidal silica. I used X-ray scattering to study the adsorbed 2-nm-thick compact layer of alkali ions at the surface of concentrated solutions of 5-nm, 7-nm, and 22-nm particles, stabilized either by NaOH or a mixture of NaOH and CsOH, with the total bulk concentration of alkali ions ranging

O. Manuel, S. A. Kamat, M. Mozina

The Sun is a magnetic plasma diffuser that selectively moves light elements like H and He and the lighter isotopes of each element to its surface. The Sun formed on the collapsed core of a supernova. It consists mostly of iron, oxygen, nickel, silicon and sulfur made near the SN core, like the rocky planets and ordinary meteorites. H ions, generated by emiss

Mariana Graña, Ruben Minasian, Michela Petrini, Alessandro Tomasiello

We perform a systematic search for N=1 Minkowski vacua of type II string theories on compact six-dimensional parallelizable nil- and solvmanifolds (quotients of six-dimensional nilpotent and solvable groups, respectively). Some of these manifolds have appeared in the construction of string backgrounds and are typically called twisted tori. We look for vacua

Eric V. Linder

Supernova experiments to characterize dark energy require a well designed low redshift program; we consider this for both ongoing/near term (e.g. Supernova Legacy Survey) and comprehensive future (e.g. SNAP) experiments. The derived criteria are: a supernova sample centered near z=0.05 comprising 150-500 (in the former case) and 300-900 (in the latter case)

G. Karagiorgi, A. Aguilar-Arevalo, J. M. Conrad, M. H. Shaevitz

We investigate the extent to which leptonic CP-violation in (3+2) sterile neutrino models leads to different oscillation probabilities for $\barν_μ\to\barν_e$ and $ν_μ\toν_e$ oscillations at MiniBooNE. We are using a combined analysis of short-baseline (SBL) oscillation results, including the LSND and null SBL results, to which we impose additional constrain

R. Debbe

The RHIC high energy collision of species ranging from p+p, p(d)+A to A+A provide access to the {small-x} component of the hadron wave function. The RHIC program has brought renewed interest in that subject with its ability to reach values of the parton momentum fraction smaller than 0.01 with studies of particle production at high rapidity. Furthermore, the

Joshua N. Winn, John A. Johnson, Geoffrey W. Marcy, R. Paul Butler

We present spectroscopy of a transit of the exoplanet HD 189733b. By modeling the Rossiter-McLaughlin effect (the anomalous Doppler shift due to the partial eclipse of the rotating stellar surface), we find the angle between the sky projections of the stellar spin axis and orbit normal to be lambda = -1.4 +/- 1.1 deg. This is the third case of a ``hot Jupite

PHENIX Collaboration, S. S. Adler

Cross sections for mid-rapidity production of direct photons in p+p collisions at the Relativistic Heavy Ion Collider (RHIC) are reported for 3 < p_T < 16 GeV/c. Next-to-leading order (NLO) perturbative QCD (pQCD) describes the data well for p_T > 5 GeV/c, where the uncertainties of the measurement and theory are comparable. We also report on the effect of r

PHENIX Collaboration, S. S. Adler

Muon production at forward rapidity (1.5 < |η| < 1.8) has been measured by the PHENIX experiment over the transverse momentum range 1 < p_T \le 3 GeV/c in sqrt(s) = 200 GeV p+p collisions at the Relativistic Heavy Ion Collider. After statistically subtracting contributions from light hadron decays an excess remains which is attributed to the semileptonic dec

Micheal S. Berger, Samuel Santana

Heavy singlet neutrinos admit Majorana masses which are not possible for the Standard Model particles. This suggest new possibilities for generating the masses and mixing angles of light neutrinos. We present a model of neutrino physics which combines the source of lepton number violation with the flavor symmetry responsible for the hierarchy in the charged

Raphael Lefevere

We consider the Gibbs representation over space-time of non-equilibrium dynamics of Hamiltonian systems defined on a lattice with local interactions. We first write the corresponding action functional as a sum of local terms, defining a local action functional. We replace the local system by a translation-invariant system whose dynamics has an identical spac

Xiang-Bin Wang, Cheng-Zhi Peng, Jian-Wei Pan

The method of decoy-state quantum key distribution (QKD) requests different intensities of light pulses. Existing theory has assumed exact control of intensities. Here we propose a simple protocol which is secure and efficient even there are errors in intensity control. In our protocol, decoy pulses and signal pulses are generated from the same father pulses

Artur Elezi

We propose, motivate and give evidence for a relation between the $\mathcal D$-modules of the quantum cohomology of a smooth complex projective manifold $X$ and a projective bundle $\PP(\oplus L_i)$ over $X$.

Roy A. Lacey, N. N. Ajitanand, J. M. Alexander, P. Chung

The shear viscosity to entropy ratio ($η/s$) is estimated for the hot and dense QCD matter created in Au+Au collisions at RHIC ($\sqrt{s_{NN}}=200$ GeV). A very low value is found $η/s \sim 0.1$, which is close to the conjectured lower bound ($1/4π$). It is argued that such a low value is indicative of thermodynamic trajectories for the decaying matter which

J. Oñorbe, R. Domínguez-Tenreiro, A. Sáiz, H. Artal

[Abridged] We have analysed the parameters characterising the mass, size and velocity dispersion both at the baryonic scale and at the halo scales of two samples of relaxed elliptical-like-objects (ELOs) identified, at z=0, in a set of self-consistent hydrodynamical simulations operating in the context of a concordance cosmological model. At the halo scale t

A. Golutvin, V. Shevchenko

We discuss a possible strategy for studies of a particular next-to-minimal flavor violation New Physics (NP) scenario at LHC. Our analysis is based on comparison of particular CKM matrix elements, which can be obtained from the processes dominated by diagrams of different topology (tree, penguin and box). We argue that the standard formalism of the overall u

J. Calsamiglia, Ll. Masanes, R. Munoz-Tapia, A. Acin

This paper has been withdrawn by the authors, due to a flaw in the proof of Theorem 1. This preprint is superseded by quant-ph/0610027, where a correct proof can be found. Thanks to Rainer Siegmund-Schultze for spotting the error.

Jesper Lykke Jacobsen

We consider tiling rectangles of size 4m x 4n by T-shaped tetrominoes. Each tile is assigned a weight that depends on its orientation and position on the lattice. For a particular choice of the weights, the generating function of tilings is shown to be the evaluation of the multivariate Tutte polynomial Z\_G(Q,v) (known also to physicists as the partition fu

Matthew P. A. Jones, Jerome Beugnon, Alpha Gaëtan, Junxiang Zhang

We demonstrate the initialisation, read-out and high-speed manipulation of a qubit stored in a single 87 Rb atom trapped in a submicron-size optical tweezer. Single qubit rotations are performed on a sub-100 ns time scale using two-photon Raman transitions. Using the ``spin-echo&#39;&#39; technique, we measure an irreversible dephasing time of 34 ms. The rea

Eduardo G. Altmann, Holger Kantz

We investigate the high dimensional Hamiltonian chaotic dynamics in $N$ coupled area-preserving maps. We show the existence of an enhanced trapping regime caused by trajectories performing a random walk {\em inside} the area corresponding to regular islands of the uncoupled maps. As a consequence, we observe long intermediate regimes of power-law decay of th

F. M. Saradzhev, F. C. Khanna, Sang Pyo Kim, M. de Montigny

Using an effective Hamiltonian including the Zeeman and internal interactions, we describe the quantum theory of magnetization dynamics when the spin system evolves non-adiabatically and out of equilibrium. The Lewis-Riesenfeld dynamical invariant method is employed along with the Liouville-von Neumann equation for the density matrix. We derive a dynamical e

A. P. Heinson

First observed in 1995, the top quark is one of a pair of third-generation quarks in the Standard Model of particle physics. It has charge +2/3e and a mass of 171.4 GeV, about 40 times heavier than its partner, the bottom quark. The CDF and D0 collaborations have identified several hundred events containing the decays of top-antitop pairs in the large datase

Lancelot F. James, Antonio Lijoi, Igor Prünster

The present paper provides exact expressions for the probability distributions of linear functionals of the two-parameter Poisson--Dirichlet process $\operatorname {PD}(α,θ)$. We obtain distributional results yielding exact forms for density functions of these functionals. Moreover, several interesting integral identities are obtained by exploiting a corresp

A. Van Daele

The Fourier transform, known in classical analysis, and generalized in abstract harmonic analysis, can also be considered in the theory of locally compact quantum groups. In this note, I discuss some aspects of this more general Fourier transform. In order to avoid technical difficulties, typical for the analytical approach, I will restrict to the algebraic

O. Oliveira, P. J. Silva

We report on the infrared limit of the quenched lattice Landau gauge gluon and ghost propagators as well as the strong coupling constant computed from large asymmetric lattices. The infrared lattice propagators are compared with the pure power law solutions from Dyson-Schwinger equations (DSE). For the gluon propagator, the lattice data is compatible with th

Giuseppe Bozzi

We summarize the status of QCD corrections for SM Higgs boson production at hadron colliders and briefly sketch the main search strategies at the LHC.

A. Makhlouf, S. Silvestrov

A Hom-algebra structure is a multiplication on a vector space where the structure is twisted by a homomorphism. The structure of Hom-Lie algebra was introduced by Hartwig, Larsson and Silvestrov and extended by Larsson and Silvestrov to quasi-hom Lie and quasi-Lie algebras. In this paper we introduce and study Hom-associative, Hom-Leibniz, and Hom-Lie admiss

J. Teyssier, A. B. Kuzmenko, D. van der Marel, F. Marsiglio

We report optical (6 meV - 4 eV) properties of a boride superconductor ZrB$_{12}$ ($T_c$ = 6 K) in the normal state from 20 to 300 K measured on high-quality single crystals by a combination of reflectivity and ellipsometry. The Drude plasma frequency and interband optical conductivity calculated by self-consistent full-potential LMTO method agree well with

J. A. Sobota, D. Tanaskovic, V. Dobrosavljevic

We study the influence of strong nonmagnetic disorder on the Ruderman-Kittel-Kasuya-Yosida (RKKY) interactions between diluted magnetic moments in metals. We find that the probability distribution for the RKKY interactions assumes strongly non-Gaussian form featuring long tails. Since such distributions cannot be characterized by its moments, we define a \te

Igor Lesanovsky, Wolf von Klitzing

We investigate the nonlinear dynamics of two coupled annular Bose-Einstein condensates (BECs). For certain values of the coupling strength the nonrotating ground state is unstable with respect to fluctuations in the higher angular momentum modes. The two branched Bogoliubov spectrum exhibits distinct regions of instability enabling one to selectively occupy

Daniel F. Litim, Jan M. Pawlowski

We construct a functional renormalisation group for thermal fluctuations. Thermal resummations are naturally built in, and the infrared problem of thermal fluctuations is well under control. The viability of the approach is exemplified for thermal scalar field theories. In gauge theories the present setting allows for the construction of a gauge-invariant th

Pascal J. Thomas, Nguyen Van Trao

Given a domain $Ω\subset \mathbb C$, the Lempert function is a functional on the space $Hol (\D,Ω)$ of analytic disks with values in $Ω$, depending on a set of poles in $Ω$. We generalize its definition to the case where poles have multiplicities given by local indicators (in the sense of Rashkovskii&#39;s work) to obtain a function which still dominates the