January 2004 arXiv papers — page 2

Stefan Denk, Volkmar Putz, Manfred Schweda, Michael Wohlgenannt

A non-local toy model whose interaction consists of smeared, non-local field operators is presented. We work out the Feynman rules and propose a power counting formula for arbitrary graphs. Explicit calculations for one loop graphs show that their contribution is finite for sufficient smearing and agree with the power counting formula. UV/IR mixing does not

Stefano Bellucci, Armen Nersessian

We propose the notion of the oscillator on Kähler space and consider its supersymmetrization in the presence of a constant magnetic field.

D. K. Hong, S. D. H. Hsu

We investigate the positivity of the Euclidean path integral measure for low-energy modes in dense fermionic matter. We show that the sign problem usually associated with fermions is absent if one considers only low-energy degrees of freedom. We describe a method for simulating dense QCD on the lattice and give a proof using rigorous inequalities that the co

Leonard S. Kisslinger

After a review of CMBR correlations and recent observations, a study of possible CMBR observations of the QCD early universe phase transition is discussed. A model for the QCD bubble walls gives the surface tension found in lattice calculations, and a 1+1 dimensional treatment in this model for bubble collisions shows an interior gluonic wall, a disk with th

Leonard S. Kisslinger

This article on light cone field theory reviews the basic concepts of the Poincare group in light cone quantum mechanics and light cone field theory. It discusses recent progress in light cone representations of the Bethe-Salpeter equation, with application to the pion form factor, and the quark Schwinger-Dyson equation. Applications are discussed for deeply

Hiroaki Abuki

Phase structure and phase transitions in dense QCD are studied using the Cornwall-Jackiw-Tomboulis (CJT) potential in the improved ladder approximation. The gap function, the condensation energy and the structure of Cooper pairs are investigated at finite temperature and density. Due to strong coupling effects at low densities, the gap, critical temperature

K. Hagiwara, E. Kou, Z. -H. Lin, C. -F. Qiao

Inclusive $J/ψ$ productions in $e^+ e^-$ annihilation is studied in the framework of NRQCD. We first review the leading-order calculations of the cross sections for $e^+ e^- \to J/ψc \bar{c}$ and $e^+ e^- \to J/ψg g$ and find that their ratio is about 1:1.5 at $\sqrt{s}\simeq 10$\gev. This result is in conflict with the current measurements by the Belle Coll

Carlo Giunti

We review critically the main assumptions on which the standard theory of neutrino oscillations is based. We show that all assumptions are realistic, except the so-called "equal momentum assumption", which however is irrelevant. We briefly review the covariant plane-wave derivation of neutrino oscillations and a quantum field theoretical wave packet

F. Deppisch, J. Kalinowski, H. Päs, A. Redelbach

In supersymmetric extensions of the Standard Model, the Yukawa and/or mass terms of the heavy neutrinos can generate lepton flavour violating slepton mass terms. These new supersymmetric sources of lepton flavour violation may both enhance the rates of charged lepton flavour violating processes, l_a -> l_b y, and generate distinct final states, like l_b l_a

H. Athar

Neutrinos with energy greater than GeV are copiously produced in the p(A,p) interactions occurring in the earth atmosphere and in our galactic plane. A comparison of the tau and mu neutrino flux in the presence of neutrino oscillations from these two astrophysical sites is presented. It is pointed out that the galactic plane tau neutrino flux dominates over

W. Buchmuller, P. Di Bari, M. Plumacher

During the process of thermal leptogenesis temperature decreases by about one order of magnitude while the baryon asymmetry is generated. We present an analytical description of this process so that the dependence on the neutrino mass parameters becomes transparent. In the case of maximal CP asymmetry all decay and scattering rates in the plasma are determin

Mischa Salle

The topological defects of the lambda phi^4 theory, kink and antikink, are studied in the Hartree approximation. This allows us to discuss quantum effects on the defects in both stationary and dynamical systems. The kink mass is calculated for a number of parameters, and compared to classical, one loop and Monte Carlo results known from the literature. We di

A. V. Anisovich, V. V. Anisovich, V. A. Nikonov

Different conclusions about quark nature of f0(980) based on the analysis of data on the reaction phi(1020) -> gamma f0(980) make it necessary to perform detailed comparison of formulae used by various groups for the calculation of partial widths of radiative decays. We carry out a comparative analysis of methods of calculation of radiative decays like phi -

Dan Green

At the LHC the overlap of minimum bias events and the jet energy deposits in a calorimeter causes a degradation in the dijet mass resolution. Guided by QCD, a judicious set of cuts can be developed to mitigate this degradation.

Simone Mercuri, Giovanni Montani

We provide a discussion about the necessity to fix the reference frame before quantizing the gravitational field. Our presentation is based on stressing how the 3+1-slicing of the space time becomes an ambiguous procedure as referred to a quantum 4-metric.

Johan Noldus

This thesis start by a review of different approaches to classical and quantum gravity. The main theme is Lorentzian Gromov Hausdorff theory which is an active diffeomorphism invariant theory on the space of Lorentz spaces (think about globally hyperbolic spacetimes). It is argued why such theory might be of significant importance for Lorentzian approaches t

K. A. Bronnikov, E. N. Chudaeva, G. N. Shikin

We study the evolution of Bianchi-I space-times filled with a global unidirectional electromagnetic field $F_{mn}$ interacting with a massless scalar dilatonic field according to the law Ψ(ϕ) F^{mn} F_{mn} where Ψ(ϕ) > 0 is an arbitrary function. A qualitative study, among other results, shows that (i) the volume factor always evolves monotonically, (ii) the

Yutaka Hosotani, Ramin G. Daghigh

Stable gravitating lumps with a false vacuum core surrounded by the true vacuum in a scalar field potential exist in the presence of fermions at the core. These objects may exist in the universe at various scales.

Richard H. Price

For geodesic motion of a particle in a stationary spacetime the $U_0$ component of particle 4-velocity is constant and is considered to be a conserved mechanical energy. We show that this concept of a conserved mechanical energy can be extended to particles that move under the influence of a ``normal force,'' a force that, in the stationary frame, is

V. Braccini, A. Gurevich, J. E. Giencke, M. C. Jewell

We investigated the effect of alloying on the upper critical field $H_{c2}$ in 12 $MgB_2$ films, in which disorder was introduced by growth, carbon doping or He-ion irradiation, finding a significant $H_{c2}$ enhancement in C-alloyed films, and an anomalous upward curvature of $H_{c2}(T)$. Record high values of $H_{c2}^{\perp}(4.2) \simeq 35T$ and $H_{c2}\|(

Silke Biermann, Ferdi Aryasetiawan, Antoine Georges

We review a recent proposal of a first principles approach to the electronic structure of materials with strong electronic correlations. The scheme combines the GW method with dynamical mean field theory, which enables one to treat strong interaction effects. It allows for a parameter-free description of Coulomb interactions and screening, and thus avoids th

N. K. Kuzmenko, V. M. Mikhajlov

The theoretical investigation of the cluster de Haas - van Alphen (dHvA) oscillations in three-dimensional systems performed for the first time. Applying a three-dimensional oscillator model to systems with electron numbers $10< N \leq 10^5$ we predict distinctive size effects: the dHvA oscillations can be observed only within a certain temperature range det

V. A. Fonoberov, E. P. Pokatilov, V. M. Fomin, J. T. Devreese

Taking into account the tetrahedral shape of a quantum dot quantum well (QDQW) when describing excitonic states, phonon modes and the exciton-phonon interaction in the structure, we obtain within a non-adiabatic approach a quantitative interpretation of the photoluminescence spectrum of a single CdS/HgS/CdS QDQW. We find that the exciton ground state in a te

U. Laletsin, N. Paddubnaya, G. Srinivasan, M. I. Bichurin

Frequency dependence of magnetoelectric (ME) coupling is investigated in trilayers of ferromagnetic alloy and piezoelectric lead zirconate titanate (PZT). The ferromagnetic phases studied include permendur, a soft magnet with high magnetostriction, iron, nickel, and cobalt. Low frequency data on ME voltage coefficient versus bias magnetic field indicate stro

M. D. Johannes D. J. Singh

We report electronic structure calculations within density functional theory for the hydrated superconductor Na_{1/3}CoO_2(1.33)H_2O and compare the results with the parent compound Na_{0.3}CoO_2. We find that the intercalation of water into the parent compound has little effect on the Fermi surface outside of the predictable effects expansion, in particular

V. M. Petrov, M. I. Bichurin V. M. Laletin, N. N. Paddubnaya, G. Srinivasan

We discuss a model that considers the bulk composite as a homogeneous medium with piezoelectric and magnetostrictive subsystems. We solve combined elastostatic, electrostatic and magnetostatic equations to obtain effective composite parameters (piezoelectric modules, magnetostriction factors, compliances, magnetoelectric coefficients) for 3-0 and 0-3 connect

J. J. Deisz

We calculate the superconducting phase diagram as a function of temperature and z-axis anisotropy in a model for tetragonal and cubic systems having strong antiferromagnetic fluctuations. The formal basis for our calculations is the fluctuation exchange approximation (FLEX) applied to the single-band Hubbard model near half-filling. For nearly cubic lattices

L. Pezze&#39;, L. Pitaevskii, A. Smerzi, S. Stringari

We investigate theoretically and experimentally the center-of-mass motion of an ideal Fermi gas in a combined periodic and harmonic potential. We find a crossover from a conducting to an insulating regime as the Fermi energy moves from the first Bloch band into the bandgap of the lattice. The conducting regime is characterized by an oscillation of the cloud

G. Srinivasan, C. P. DeVreugd, R. Hayes, M. I. Bichurin

The observation of strong magnetoelectric effects is reported in thick film bilayers and multilayers of ferrite-lead titanate zirconate (PZT) and lanthanum nanganite-PZT. The ferrites used in our studies included pure and zinc substituted cobalt-, nickel- and lithium ferrites. Samples were prepared by sintering 10-40 mm thick films obtained by tape-casting.

I. Farkas, I. Derenyi, G. Palla, T. Vicsek

In this article we give an in depth overview of the recent advances in the field of equilibrium networks. After outlining this topic, we provide a novel way of defining equilibrium graph (network) ensembles. We illustrate this concept on the classical random graph model and then survey a large variety of recently studied network models. Next, we analyze the

James W. Dufty, Matthieu H. Ernst

The autocorrelation functions for the force on a particle, the velocity of a particle, and the transverse momentum flux are studied for the power law potential $v(r)=ε(σ/r)^ν$ (soft spheres). The latter two correlation functions characterize the Green-Kubo expressions for the self-diffusion coefficient and shear viscosity. The short time dynamics is calculat

Martin Hohenadler, Hans Gerd Evertz, Wolfgang von der Linden

A recently developed quantum Monte Carlo approach to the Holstein model with one electron [PRB 69, 024301 (2004)] is extended to two and three dimensional lattices. A moderate sign problem occurs, which is found to diminish with increasing system size in all dimensions, and not to affect simulations significantly. We present an extensive study of the influen

S. Pilgram, K. E. Nagaev, M. Buttiker

We calculate the frequency dispersion of the third cumulant of current in diffusive-metal contacts. The cumulant exhibits a dispersion at the inverse time of diffusion across the contact, which is typically much smaller than the inverse $RC$ time. This dispersion is much more pronounced in the case of strong electron-electron scattering than in the case of p

G. O. Andrianov, I. L. Drichko, A. M. Diakonov, I. Yu. Smirnov

The surface acoustic wave (SAWs) attenuation coefficient $Γ$ and the velocity change $ΔV /V$ were measured for $p$-type Si/SiGe heterostructures in the temperature range 0.7 - 1.6 K as a function of external magnetic field $H$ up to 7 T and in the frequency range 30-300 MHz in the hole Si/SiGe heterostructures. Oscillations of $Γ$ (H) and $ΔV /V$ (H) in a ma

S. Dhara, B. Sundaravel, T. R. Ravindran, K. G. M. Nair

Gold nanoclusters are grown by 1.8 MeV Au++ implantation in silica matrix and subsequent air annealing in the temperature range of 873K-1273K. Post-annealed samples show plasmon resonance in the optical region (~ 2.38-2.51 eV) for average cluster radii ~1.04-1.74 nm. A blueshift of the plasmon peak is observed with decreasing cluster size in the annealed sam

Damien Challet, Matteo Marsili, Andrea De Martino

A finite memory is introduced in the score dynamics of Minority Games. As expected, this removes the dependence of the stationary state on the initial conditions. However, it also causes an unexpected increase of fluctuations in grand-canonical models for very large times. Current analytical methods are inadequate to solve this simple and natural extension.

Masahiro Sato, Masaki Oshikawa

We present a systematic study of coupled $S=1/2$ Heisenberg antiferromagnetic chains in an effective staggered field. We investigate several effects of the staggered field in the {\em higher} ({\em two or three}) {\em dimensional} spin system analytically. In particular, in the case where the staggered field and the inter-chain interaction compete with each

Ferdi Aryasetiawan, Silke Biermann, Antoine Georges

We give a detailed description of a recently proposed first principles approach to the electronic structure of strongly correlated materials. The method combines the GW approximation with dynamical mean field theory. It is designed to describe Coulomb interactions and screening effects without adjustable parameters, thus avoiding the conceptual problems inhe

Alex J. Levine

I propose a variation of the standard worm--like chain model to account for internal order parameter (helix/coil) fields on the polymer chain. This internal order parameter field influences polymer conformational statistics by locally modifying the persistence length of the chain. Using this model, I make predictions for the bending and stretching response o

Hisashi Kondo, Tôru Moriya

We study spin fluctuation (SF) mediated superconductivity (SC) in a half-filled square lattice Hubbard model with the transfer matrices -t between nearest neighbor sites and -t&#39; between a half of next nearest neighbor sites neighboring along only one of the <1,1> directions, considering application of this model to organic kappa-(BEDT-TTF)2X compounds. V

T. Aste, M. Saadatfar, A. Sakellariou, T. J. Senden

Bead packs of up to 150,000 mono-sized spheres with packing densities ranging from 0.58 to 0.64 have been studied by means of X-ray Computed Tomography. These studies represent the largest and the most accurate description of the structure of disordered packings at the grain-scale ever attempted. We investigate the geometrical structure of such packings look

F. Aryasetiawan, M. Imada, A. Georges, G. Kotliar

We propose a systematic procedure for constructing effective models of strongly correlated materials. The parameters, in particular the on-site screened Coulomb interaction U, are calculated from first principles, using the GW approximation. We derive an expression for the frequency-dependent U and show that its high frequency part has significant influence

Takao Watanabe, Takenori Fujii, Azusa Matsuda

Large high-quality single crystals of Bi2Sr2Can-1CunO2n+4+d (n = 2, 3) were successfully grown using an improved traveling solvent floating zone (TSFZ) method, which features a slow growth rate and steep temperature gradient along the melting zone. By measuring anisotropic resistivities and susceptibilities of Bi2Sr2CaCu2O8+d, the characteristic pseudogap te

Chi-Ho Cheng, Pik-Yin Lai

The behavior of a polyelectrolyte adsorbed on a charged surface of high-dielectric constant is studied by both Monte-Carlo simulation and analytical methods. It is found that in a low ionic strength medium, the transition is first-order with the repulsive charged surface. The order parameter which characterize the polyelectrolyte adsorption, the surface mono

Carsten Raas, Götz S. Uhrig, Frithjof B. Anders

The quantitative control of the dynamic correlations of single impurity Anderson models is essential in several very active fields. We analyze the one-particle Green function with a constant energy resolution by dynamic density-matrix renormalization. In contrast to other approaches, sharp dominant resonances at high energies are found. Their origin and impo

Junren Shi, S. -J Tang, Biao Wu, P. T. Sprunger

We propose a systematic procedure to directly extract the Eliashberg function for electron-phonon coupling from high-resolution angle-resolved photoemission data. The procedure is successfully applied to the Be(1010) surface, providing new insights to electron-phonon coupling at this surface. The method is shown to be robust against imperfections in experime

A. Izmalkov, M. Grajcar, E. Il&#39;ichev, N. Oukhanski

A two-level system traversing a level anticrossing has a small probability to make a so-called Landau-Zener (LZ) transition between its energy bands, in deviation from simple adiabatic evolution. This effect takes on renewed relevance due to the observation of quantum coherence in superconducting qubits (macroscopic &#34;Schrodinger cat&#34; devices). We rep

Jennifer A. Johnson, Michael Bolte

The CH star CS 31062-050 ([Fe/H]=-2.42) is one of the most useful stars yet discovered for evaluating the s-process in metal-poor stars. It is very abundant in heavy elements (e.g., [La/Fe]=2.2), and its relatively cool temperature and low gravity mean that there are many lines of interesting elements present in the spectrum. We measured the abundances of 22

David G. Russell

The Tully-Fisher relationship is subject to morphological type dependence such that galaxies of morphology similar to ScI galaxies and Seyfert galaxies are more luminous at a given rotational velocity than galaxies of other morphological classification. This effect is most prevalent in the B-band. It is shown that the type effect is not simply an artifact of

Robert J. Vanderbei, N. Jeremy Kasdin, David N. Spergel

We present yet another new family of masks for high-contrast imaging as required for the to-be-built terrestrial planet finder space telescope. The ``best&#39;&#39; design involves a square entrance pupil having a 4-vane spider, a square image-plane mask containing a plus-sign shaped occulter to block the starlight inside 0.6 lambda/D, and a Lyot-plane mask

M. Derouich, S. Sahal-Bréchot, P. S. Barklem

The semi-classical theory of collisional depolarization of spectral lines of neutral atoms by atomic hydrogen (Derouich et al. 2003a; Derouich et al. 2003b; Derouich et al. 2004 and references therein) is extended to spectral lines of singly ionised atoms. In this paper we apply our general method to the particular cases of the 3d $^2D$ and $4p$ $^2P$ states

P. Petit, J. -F. Donati, A. Collier Cameron

The surface differential rotation of active solar-type stars can be investigated by means of Doppler and Zeeman-Doppler Imaging, both techniques enabling one to estimate the short-term temporal evolution of photospheric structures (cools spots or magnetic regions). After describing the main modeling tools recently developed to guarantee a precise analysis of

B. McKernan, T. Yaqoob

We report the detection of complex Fe K line emission from a Chandra High Energy Transmission Grating Spectrometer observation of the Seyfert 1 galaxy IC 4329A. The line emission is double-peaked, one peak centered at ~6.3 keV, and the other at ~6.9 keV in the source rest frame. When modeled by Gaussians, the lower energy peak is resolved by the HEG at >99%

F. de Felice, M. T. Crosta, A. Vecchiato, M. G. Lattanzi

We develop here a new approach for the relativistic modeling of the photons moving into a quasi-Minkowskian space-time, where the metric is generated by an arbitrary n-body distribution within an isolated Solar System. Our model is built on the prescriptions of the theory of General Relativity and leaves the choices of the metric, as well as that of the moti

Giuseppe Gavazzi, Antonio Zaccardo, Gerry Sanvito, Alessandro Boselli

Drift-scan mode (3600-6800 A) spectra with 500<R<1000 resolution are presented for 333 galaxies members to nearby clusters, covering the whole Hubble sequence. The majority (225) were obtained for galaxies in the Virgo cluster where a completeness of 36%, if all Hubble types are considered, and of 51%, restricting to late-types, was reached at m_p<=16. Our d

F. L. Schoeier, J. K. Jorgensen, E. F. van Dishoeck, G. A. Blake

High angular resolution H2CO 218 GHz line observations have been carried out toward the low-mass protostars IRAS 16293-2422 and L1448-C using the Owens Valley Millimeter Array at ~2&#34; resolution. Simultaneous 1.37 mm continuum data reveal extended emission which is compared with that predicted by model envelopes constrained from single-dish data. For L144

John Swain

The present status of anisotropy studies for the highest energy cosmic rays is presented including the first full sky survey. Directions and prospects for the future are also discussed in light of new statistical methods and the last quantities of data expected in the near future from the Pierre Auger Observatory.

Richard. J. Tuffs, Cristina C. Popescu, Heinrich J. Voelk, Nikolaos D. Kylafis

We present new calculations of the attenuation of stellar light from spiral galaxies using geometries for stars and dust which can reproduce the entire spectral energy distribution from the UV to the FIR/submm and can also account for the surface brightness distribution in both the optical/NIR and FIR/submm. The calculations are based on the model of Popescu

X. Y. Hong, D. R. Jiang, L. I. Gurvits, M. A. Garrett

We present the results of a number of high resolution radio observations of the AGN 1156+295. These include multi-epoch and multi-frequency VLBI, VSOP, MERLIN and VLA observations made over a period of 50 months. The 5 GHz MERLIN images trace a straight jet extending to 2 arcsec at P.A. -18 degrees. Extended low brightness emission was detected in the MERLIN

A. Ramirez, J. A. de Diego, D. Dultzin-Hacyan, J. N. Gonzalez-Perez

We present BVR photometric observations of the blazar PKS 0736+017. These observations were carried out with three telescopes in Mexico and two in Spain between December 1998 and April 2003. PKS 0736+017 shows remarkable variation at different timescales and amplitudes. Maximum brightness was detected on December 19, 2001 (B=14.90+/-0.01, V=14.34+/-0.01, and

James S. Bullock, Kathryn V. Johnston

If the favored hierarchical cosmological model is correct, then the Milky Way system should have accreted and subsequently tidally destroyed ~100 low-mass galaxies in the past ~12 Gyr. We model this process using a hybrid semi-analytic plus N-body approach and show that the disrupted systems lead naturally to stellar halos with masses and density profiles mu

Enrico Nardi

A new method to study the effects of neutrino masses on a supernova neutrino signal is proposed. The method relies exclusively on the analysis of the full statistics of neutrino events, it is independent of astrophysical assumptions, and does not require the observation of any additional phenomenon to trace possible delays in the neutrino arrival times. A st

Benjamin D. Wandelt

In this talk I describe MAGIC, an efficient approach to covariance estimation and signal reconstruction for Gaussian random fields (MAGIC Allows Global Inference of Covariance). It solves a long-standing problem in the field of cosmic microwave background (CMB) data analysis but is in fact a general technique that can be applied to noisy, contaminated and in

Benjamin D. Wandelt

The Cosmic Microwave Background (CMB) is an abundant source of cosmological information. However, this information is encoded in non-trivial ways in a signal that is difficult to observe. The resulting challenges in extracting this information from CMB data sets have created a new frontier. In this talk I will discuss the challenges of CMB data analysis. I r

J. D. Vergados

In this paper we review the theoretical issues involved in the direct detection of supersymmetric (SUSY) dark matter. After a brief discussion of the allowed SYSY parameter space we focus on the determination of the traditional neutralino detection rates, in experiments which measure the energy of the recoiling nucleus, such as the coherent and spin induced

Daniel Chan, Paul Hacking, Colin Ingalls

We classify the possible ramification data and etale local structure of orders over surfaces with canonical singularities.

Amir Sagiv, Eli Waxman, Abraham Loeb

(Abr) The origin and structure of magnetic fields in Gamma-Ray Burst (GRB) fireball plasmas are two of the most important open questions in all GRB models. We show that the structure and strength of the magnetic field may be constrained by radio and IR observations of the early afterglow, where plasma effects on the polarization of propagating radiation are

Robert H. Brandenberger, Anupam Mazumdar, Masahide Yamaguchi

The recent high precision maps of cosmic microwave anisotropies combined with measurements of the galaxy power spectrum from new large-scale redshift surveys have allowed stringent bounds on the sum of the neutrino masses to be placed. The past analyses, however, have implicitly assumed that the spectrum of primordial density fluctuations is adiabatic and co

Constantine Yannouleas, Uzi Landman

Conditional probability distributions from exact diagonalization are used to investigate the crystalline or liquid character of the downward cusp states in parabolic quantum dots (QD&#39;s) at high magnetic fields. These states are crystalline in character for fractional fillings covering both low and high values, unlike the liquid Jastrow-Laughlin wave func

A. L. Chernyshev, A. H. Castro Neto, S. R. White

We study competition between different phases in a strongly correlated nano-structure with an edge. Making use of the self-consistent Green&#39;s function and density matrix renormalization group methods, we study a system described by the t-Jz and t-J models on a strip of a square lattice with a linear hole density n_||. At intermediate interaction strength

Murat M. Kaskulov, Heinz Clement

The effect of correlated scalar-isoscalar two-pion exchange (CrTPE) modes is considered in connection with central and spin-orbit parts of the NN force. The two-pion correlation function is coupled directly to the scalar form factor of the nucleon which we calculate in the large-N(C) limit where the nucleon can be described as a soliton of an effective chira

Charles Tahan, Robert Joynt

Silicon is a leading candidate material for spin-based devices, and two-dimensional electron gases (2DEGs) formed in silicon heterostructures have been proposed for both spin transport and quantum dot quantum computing applications. The key parameter for these applications is the spin relaxation time. Here we apply the theory of D&#39;yakonov and Perel&#39;

Minos Axenides, Konstantinos Dimopoulos

We present a unified model of dark matter and dark energy. The dark matter field is a modulus corresponding to a flat direction of supersymmetry, which couples, in a hybrid type potential, with the dark energy field. The latter is a light scalar, whose direction is stabilized by non-renormalizable terms. This quintessence field is kept `locked&#39; on top of

Hideaki Kudoh

To test the strong-gravity regime in Randall-Sundrum braneworlds, we consider black holes bound to a brane. In a previous paper, we studied numerical solutions of localized black holes whose horizon radii are smaller than the AdS curvature radius. In this paper, we improve the numerical method and discuss properties of the six dimensional (6D) localized blac

V. M. Kaspi, S. M. Ransom, D. C. Backer, R. Ramachandran

We report on the first Green Bank Telescope observations at 427, 820 and 1400 MHz of the newly discovered, highly inclined and relativistic double pulsar binary. We focus on the brief eclipse of PSR J0737-3039A, the faster pulsar, when it passes behind PSR J0737-3039B. We measure a frequency-averaged eclipse duration of 26.6 +/- 0.6 s, or 0.00301 +/- 0.00008

Qaisar Shafi, Zurab Tavartkiladze

Within a democratic approach based on discrete symmetries, we show how the charged lepton mass hierarchies and bilarge neutrino mixings can be realized. For the third mixing angle we find $\te_{13}\sim \sq{\fr{\De m_{\rm sol}^2}{\De m_{\rm atm}^2}}\sim 0.1-0.2$.

Yu-xi Liu, Sahin K. Ozdemir, Adam Miranowicz, Masato Koashi

Entanglement of the excitonic states in the system of two coupled semiconductor microcrystallites, whose sizes are much larger than the Bohr radius of exciton in bulk semiconductor but smaller than the relevant optical wavelength, is quantified in terms of the entropy of entanglement. It is observed that the nonlinear interaction between excitons increases t

F. Rioual, T. Biben, C. Misbah

Vesicles under a shear flow exhibit a tank-treading motion of their membrane, while their long axis points with an angle < 45 degrees with respect to the shear stress if the viscosity contrast between the interior and the exterior is not large enough. Above a certain viscosity contrast, the vesicle undergoes a tumbling bifurcation, a bifurcation which is kno

R. Darradi, J. Richter, S. E. Krueger

We use a variational mean-field like approach, the coupled cluster method (CCM) and exact diagonalization to investigate the ground-state order-disorder transition for the square lattice spin-half XXZ model with two different nearest-neighbor couplings $J$ and $J&#39;$. Increasing $J&#39; > J$ the model shows in the isotropic Heisenberg limit a second-order

M. Monemzadeh, A. Shirzad

We show that the BFT embedding method is problematic for mixed systems (systems possessing both first and second class constraints). The Chern-Simons theory as an example is worked out in detail. We give two methods to solve the problem leading to two different types of finite order BFT embedding for Chern-Simons theory.

Xavier Garcia i Tormo, Joan Soto

We analyze the end-point region of the photon spectrum in semi-inclusive radiative decays of very heavy quarkonium (m alpha_s^2 >> Lambda_QCD). We discuss the interplay of the scales arising in the Soft-Collinear Effective Theory, m, m(1-z)^{1/2} and m(1-z) for z close to 1, with the scales of heavy quarkonium systems in the weak coupling regime, m, m alpha_

K. Sasaki, Y. Kawazoe, R. Saito

We present fractional flux periodicity in the ground state of planar systems made of a square lattice whose boundary is compacted into a torus. The ground-state energy shows a fractional period of the fundamental unit of magnetic flux depending on the twist around the torus axis.

Kazuhide Ichikawa, Masahiro Kawasaki

We calculate primordial abundances of light elements produced during big bang nucleosynthesis when the fine structure constant and/or the cosmic expansion rate take non-standard values. We compare them with the recent values of observed D, He4 and Li7 abundances, which show slight inconsistency among themselves in the standard big bang nucleosynthesis scenar

Rasulkhozha S. Sharafiddinov

The united rest mass and charge of a particle correspond to the two forms of the same regularity of the unified nature of its ultimate structure. Each of them contains the electric, weak, strong and the gravitational contributions. As a consequence, the force of an attraction among the two neutrinos and force of their repulsion must be defined from the point

Masashi Hayakawa, Nobuyuki Ishibashi

Recently Sekino and Yoneya proposed a way to regularize the world volume theory of membranes wrapped around $S^1$ by matrices and showed that one obtains matrix string theory as a regularization of such a theory. We show that this correspondence between matrix string theory and wrapped membranes can be obtained by using the usual M(atrix) theory techniques.

L. -M. Duan

We propose a method to achieve scalable quantum computation based on fast quantum gates on an array of trapped ions, without the requirement of ion shuttling. Conditional quantum gates are obtained for any neighboring ions through spin-dependent acceleration of the ions from periodic photon kicks. The gates are shown to be robust to influence of all the othe

Pawel Wocjan

A major topic of (classical) ergodic theory is to examine qualitatively how the phase space of dynamical systems is penetrated by the orbits of their dynamics. We consider interacting qubit systems with dynamics according to 4-local Hamiltonians and continuous quantum random walks. For these systems one could use the von Neumann entropy of the time-average t

G. Molina-Terriza, A. Vaziri, J. Rehacek, Z. Hradil

A general protocol in Quantum Information and Communication relies in the ability of producing, transmitting and reconstructing, in general, qunits. In this letter we show for the first time the experimental implementation of these three basic steps on a pure state in a three dimensional space, by means of the orbital angular momentum of the photons. The rec

Ulrich Mohrhoff

Zurek claims to have derived Born&#39;s rule noncircularly in the context of an ontological no-collapse interpretation of quantum states, without any &#34;deus ex machina imposition of the symptoms of classicality.&#34; After a brief review of Zurek&#39;s derivation it is argued that this claim is exaggerated if not wholly unjustified. In order to demonstrat

Ulrich Mohrhoff

Zurek&#39;s existential interpretation of quantum mechanics suffers from three classical prejudices, including the belief that space and time are intrinsically and infinitely differentiated. They compel him to relativize the concept of objective existence in two ways. The elimination of these prejudices makes it possible to recognize the quantum formalism&#3

Monica Varvella, Enrico Calloni, Luciano Di Fiore, Leopoldo Milano

This paper deals with the use of a magnetic levitation system as a part of a multi-stage seismic attenuator for gravitational wave interferometric antennas. The proposed configuration uses permanent magnets in attraction to balance the suspended weight, plus a closed loop position control to obtain a stable levitation. The system is analyzed using a MATLAB s

M. C. Fujiwara, M. Amoretti, G. Bonomi, A. Bouchta

We demonstrate three-dimensional annihilation imaging of antiprotons trapped in a Penning trap. Exploiting unusual feature of antiparticles, we investigate a previously unexplored regime in particle transport; the proximity of the trap wall. Particle loss on the wall, the final step of radial transport, is observed to be highly non-uniform, both radially and

Jorge Carmona, Mike Cook, Jimmy Schmoke, Katie Harper

The Center for Astrophysics,Space Physics, and Engineering Research (CASPER) has completed construction and calibration of a Light Gas Gun (LGG), which is used for low velocity impact studies. At geosynchronous orbit, space debris can impact commercial satellites at velocities of 500 m/s [1] reducing their useful lifetime. Additionally, there is an ever-incr

B. D. Lindsay, K. W. Orr, T. W. Hyde, L. Barge

Numerical simulations show that planetesimal systems with unevenly distributed masses may actually be more stable than those where all the bodies are of roughly equal size.

S. Sahoo, G. F. Gribakin

We performed an overview of the inner shell excitation phenomena in the study of electron recombination with multiply charged complex ions such as Au$^{q+}$ (q=49-52) and Pb$^{53+}$. It is found the the inner shell excitations play a significant role in the low energy electron recombination. Taking into account these inner shell excitations we have calculate

S Sahoo, G. F. Gribakin, V Dzuba

We performed an extensive study of configuration mixing between the doubly excited (doorway) states and complex multiply excited states of U$^{28+}$ near its ionization threshold. The detailed investigation of complex spectrum and analysis of the statistics of eigenstate components show that the dielectronic (doorway) states weakly mixed with each other. How

N. A. Mortensen, M. D. Nielsen, J. R. Folkenberg, C. Jakobsen

We consider an air-silica honeycomb lattice and demonstrate a new approach to the formation of a core defect. Typically, a high or low-index core is formed by adding a high-index region or an additional air-hole (or other low-index material) to the lattice, but here we discuss how a core defect can be formed by manipulating the cladding region rather than th

H. Ikeda, J. W. Flanagan, H. Fukuma, S. Hiramatsu

KEKB is a high luminosity e+e- collider for studying B mesons and has achieved the design luminosity of 1034cm-2s-1 in 2003. In order to get higher luminosity, we tested negative momentum compaction optics in the summer of 2003. We measured the bunch length using three methods at 0.7mA to 1.17mA bunch current and confirmed the length was shortened with the n

K. A. Bugaev

A detailed analysis of the coupled relativistic kinetic equations for two domains separated by a hypersurface having both space- and time-like parts is presented. Integrating the derived set of transport equations, we obtain the correct system of the hydro+cascade equations to model the relativistic nuclear collision process. Remarkably, the conservation law

G. Stoicea, M. Petrovici, A. Andronic, N. Herrmann

Detailed studies of the azimuthal dependence of the mean fragment and flow energies in the Au+Au and Xe+CsI systems are reported as a function of incident energy and centrality. Comparisons between data and model calculations show that the flow energy values along different azimuthal directions could be viewed as snapshots of the fireball expansion with diff