April 2007 arXiv papers — page 6

Cristina Comaniciu, H. Vincent Poor

In this paper, a hierarchical cross-layer design approach is proposed to increase energy efficiency in ad hoc networks through joint adaptation of nodes' transmitting powers and route selection. The design maintains the advantages of the classic OSI model, while accounting for the cross-coupling between layers, through information sharing. The proposed j

Wolfram Weise, Claudia Ratti, Simon Roessner

QCD thermodynamics is studied using a model which combines Polyakov loop dynamics with spontaneous chiral symmetry breaking and its restoration (the PNJL model). The input is fixed entirely by pure-gauge lattice QCD results and by pion properties in vacuum. Successful comparisons with results from thermal lattice QCD are achieved, including extrapolations to

Leslie Hebb, Larry Petro, Holland C. Ford, David R. Ardila

We present high cadence, high precision multi-band photometry of the young, M1Ve, debris disk star, AU Microscopii. The data were obtained in three continuum filters spanning a wavelength range from 4500Åto 6600Å, plus H$α$, over 28 nights in 2005. The lightcurves show intrinsic stellar variability due to starspots with an amplitude in the blue band of 0.051

J. Gracia-Carpio, P. Planesas, L. Colina

We present the results of high resolution mapping of the CO(1-0) and CO(2-1) emission of the ultraluminous infrared galaxy (ULIRG) IRAS 10190+1322, with the IRAM interferometer, down to an angular resolution of ~0.3 arcsec. This object is composed of two interacting galaxies with a projected nuclear separation of 6 kpc, and was selected to analyze the physic

S. Garcia-Burillo, F. Combes, R. Neri, A. Fuente

We report the detection of a massive (M(gas) > 5x10^9 Msun) molecular/dusty disk of 1.4kpc-size fueling the central engine of the Compact Symmetric Object (CSO) 4C31.04 based on high-resolution (0.5''--1.2'') observations done with the IRAM Plateau de Bure interferometer (PdBI). These observations allow for the first time to detect and map th

Richard L. Hall, Wolfgang Lucha

General analytic energy bounds are derived for N-boson systems governed by semirelativistic Hamiltonians of the form H=\sum_{i=1}^N \sqrt(p_i^2+m^2) + \sum_{1=i<j}^N V(r_{ij}), where V(r) is a static attractive pair potential. A translation-invariant model Hamiltonian H_c is constructed. We conjecture that <H> \ge <H_c> generally, and we prove this for N=3,

Jean-Pierre Luminet

We provide an epistemological analysis of the developments of relativistic cosmology from 1917 to 2006, based on the seminal articles by Einstein, de Sitter, Friedmann, Lemaitre, Hubble, Gamow and other main historical figures of the field. It appears that most of the ingredients of the present-day standard cosmological model, such as the accelation of the e

Heavy Flavor Averaging Group

This article reports the world averages for measurements on b-hadron properties obtained by the Heavy Flavor Averaging Group (HFAG) using the available results at the end of 2006. In the averaging, the input parameters used in the various analyses are adjusted (rescaled) to common values, and all known correlations are taken into account. The averages includ

Paul Benioff

This paper extends earlier work on quantum theory representations of natural numbers N, integers I, and rational numbers Ra to describe a space of these representations and transformations on the space. The space is parameterized by 4-tuple points in a parameter set. Each point, (k,m,h,g), labels a specific representation of X = N, I, Ra as a Fock space F^{X

F. Belletti, M. Cotallo, A. Cruz, L. A. Fernández

We describe the hardwired implementation of algorithms for Monte Carlo simulations of a large class of spin models. We have implemented these algorithms as VHDL codes and we have mapped them onto a dedicated processor based on a large FPGA device. The measured performance on one such processor is comparable to O(100) carefully programmed high-end PCs: it tur

P. Weltevrede, B. W. Stappers, R. T. Edwards

A large sample of pulsars has been observed to study their subpulse modulation at an observing wavelength (when achievable) of both 21 and 92 cm using the Westerbork Synthesis Radio Telescope. In this paper we present the 92-cm data and a comparison is made with the already published 21-cm results. We analysed 191 pulsars at 92 cm using fluctuation spectra.

Maxime Gabella, Tony Gherghetta, Joel Giedt

We propose a gravitational dual of ``single-sector&#39;&#39; models of supersymmetry breaking which contain no messenger sector and naturally explain the scale of supersymmetry breaking and the fermion mass hierarchy. In five dimensions these models can be given a simple interpretation. Inspired by flux-background solutions of type IIB supergravity, a metric

Matteo Beccaria

We consider twist-3 operators in the sl(2) sector of N=4 SYM built out of three scalar fields with derivatives. We extract from the Bethe Ansatz equations of this sector the exact lowest anomalous dimension gamma(s) of scaling fields for several values of the operator spin s. We propose compact closed expressions for the spin dependence of gamma(s) up to the

A. Ballesteros, O. Civitarese, F. J. Herranz, M. Reboiro

Higgs algebras are used to construct rotational Hamiltonians. The correspondence between the spectrum of a triaxial rotor and the spectrum of a cubic Higgs algebra is demonstrated. It is shown that a suitable choice of the parameters of the polynomial algebra allows for a precise identification of rotational properties. The harmonic limit is obtained by a co

Ilia Gogoladze, Chin-Aik Lee, Tianjun Li, Qaisar Shafi

We discuss fermion masses and mixings in models derived from orbifold GUTs such that gauge coupling unification is achieved without low energy supersymmetry by utilizing a non-canonical U(1)_Y. A gauged U(1)_X flavor symmetry plays an essential role, and the Green-Schwarz mechanism is invoked in anomaly cancellations. Models containing vector-like particles

Gernot Maier, Johannes Knapp

The dominant background for observations of gamma-rays in the energy region above 50 GeV with Imaging Atmospheric Cherenkov telescopes are cosmic-ray events. The images of most of the cosmic ray showers look significantly different from those of gamma-rays and are therefore easily discriminated. However, a small fraction of events seems to be indistinguishab

Antonio Bernini, Elisa Pergola

Not long ago, Claesson and Mansour proposed some conjectures about the enumeration of the permutations avoiding more than three Babson - Steingr\&#39;ımsson patterns (generalized patterns of type $(1,2)$ or $(2,1)$). The avoidance of one, two or three patterns has already been considered. Here, the cases of four and five forbidden patterns are solved and the

E. A. Bergshoeff, J. Hartong, A. Ploegh, J. Rosseel

We discuss how all variant 10d and 11d maximal supergravities, including star supergravities and supergravities in different signatures, can be obtained as different real slices of three complex actions. As an application we study the recently introduced domain-wall/cosmology correspondence in this approach. We give an example in 9d and 10d where the domain-

Jan Forbrich, Maria Massi, Eduardo Ros, Andreas Brunthaler

In order to directly study the role of magnetic fields in the immediate vicinity of protostars, we use Very-Long-Baseline Interferometry (VLBI), aiming at the detection of non-thermal centimetric radio emission. This is technically the only possibility to study coronal emission at sub-AU resolution. We performed VLBI observations of the four nearby protostar

H. -J. Kluge, W. Quint, D. F. A. Winters

Trapping and cooling techniques have become very important for many fundamental experiments in atomic physics. When applied to highly charged ions confined in Penning traps, these procedures are very effective for testing quantum electrodynamics in extreme electromagnetic fields produced by heavy highly charged ions such as uranium U$^{91+}$. In addition, fu

Rohta Takahashi

We present the basic equations and sample solutions for the steady-state global transonic solutions of the advection-dominated accretion flows (ADAFs) with a causal viscosity prescription. The procedures for the stable numerical calculations and all explicit formula for obtaining the solutions of ADAFs are also presented. We solve the transonic solutions of

D. Trevese, F. Vagnetti, S. Puccetti, F. Fiore

The maximum number density of Active Galactic Nuclei (AGNs), as deduced from X-ray studies, occurs at z<~1, with lower luminosity objects peaking at smaller redshifts. Optical studies lead to a different evolutionary behaviour, with a number density peaking at z~2 independently of the intrinsic luminosity, but this result is limited to active nuclei brighter

Celal Harabati, Kenneth G. Kay

Semiclassical calculations using the Herman-Kluk initial value treatment are performed to determine energy eigenvalues of bound and resonance states of the collinear helium atom. Both the $eZe$ configuration (where the classical motion is fully chaotic) and the $Zee$ configuration (where the classical dynamics is nearly integrable) are treated. The classical

E. Montanari, G. Calestani, L. Righi, E. Gilioli

The structural properties of BiMn$O_3$ were determined from neutron powder diffraction data as a function of temperature and magnetic field. The structure at all temperatures was found to be centrosymmetric with space group $C2/c$, which is incompatible with ferroelectricity. At T$_C\simeq 100 K$, we observed the onset of a large magnetoelastic strain, propo

Thomas Heinzl, Anton Ilderton

We investigate the transition from second to first order systems. This transforms configuration space into phase space and hence introduces noncommutativity in the former. Quantum mechanically, the transition may be described in terms of spectral flow. Gaps in the energy or mass spectrum may become large which effectively truncates the available state space.

Z. Moktadir, H. Wensink, M. Kraft

The blasting of brittle materials with sharp particles is an important fabrication technology in many industrial processes. In particular, for micro-systems, it allows the production of devices with feature sizes down to few tens of microns. An important parameter of this process is the surface roughness of post-blasted surfaces. In this work the scaling pro

Renyue Cen, Mario A. Riquelme

We differentiate between the metal enrichment of the gas in virialized minihalos and that of the intergalactic medium at high redshift, pertinent to cosmological reionization, with the initial expectation that gas in the high density regions within formed dark matter halos may be more robust thus resistant to mixing with lower density intergalactic medium. U

Christoph Sieg

To endow the N=1* SYM theory with quarks, we embed D7-brane probes into its gravity dual, known as the Polchinski-Strassler background. The non-vanishing 3-form flux G_3 in the background is dual to mass terms for the three adjoint chiral superfields, deforming the N=4 SYM theory to the N=1* SYM theory. We keep its three mass parameters independent. This gen

P. Schwartz, B. Schmieder, P. Heinzel

We present non-LTE diagnostics of the filament observed by SOHO/SUMER on May 27, 2005 in the whole Lyman series. The filament was situated close to the disk center. The Ly_alpha observations were carried out with normal voltage of detector A. The slit was placed at the central part of the detector -- outside the Ly_alpha attenuator. Therefore, the observed p

T. Mori

We report on a high statistics measurement of the total and differential cross sections of the process gamma gamma -> pi^+ pi^- in the pi^+ pi^- invariant mass range 0.8 GeV/c^2 < W < 1.5 GeV/c^2 with 85.9 fb^{-1} of data collected at sqrt{s}=10.58 GeV and 10.52 GeV with the Belle detector. A clear signal of the f_0(980) resonance is observed in addition to

Antoni Szczurek, Anna Rybarska, Gabriela Slipek

We compare results of $k_t$-factorization approach and next-to-leading order collinear-factorization approach for dijet correlations in proton-proton collisions at RHIC energies. We discuss correlations in azimuthal angle as well as correlations in two-dimensional space of transverse momenta of two jets. Some $k_t$-factorization subprocesses are included for

Rennan Barkana

Analytical approaches to galaxy formation and reionization are based on the mathematical problem of random walks with barriers. The statistics of a single random walk can be used to calculate one-point distributions ranging from the mass function of virialized halos to the distribution of ionized bubble sizes during reionization. However, an analytical calcu

S. V. Godambe, R. C. Rannot, K. S. Baliyan, A. K. Tickoo

We have observed the BL Lac object 1ES2344+514 (z = 0.044) in Very High Energy (VHE) gamma-ray and near-infrared wavelength bands with TACTIC and MIRO telescopes respectively. The observations were made from 18th October to 9th December 2004 and 27th October 2005 to 1st January 2006. Detailed analysis of the TACTIC data indicates absence of a statistically s

Hellmut Baumgaertel

The paper contains critical comments to the paper mentioned in the title from the mathematical point of view

A. Herrero

We review recent advances in our understanding of massive stars through the analysis of their spectra. Improvements in model atmospheres and analysis methods are briefly discussed. Results obtained for stars in the Local Group are compared and the present status of different open questions, like the temperature scale of OB stars, the Wind Momentum-Luminosity

J. Karpinski, N. Zhigadlo, S. Katrych, B. Batlogg

The effect of Li substitution for Mg and of Li-C co-substitution on the superconducting properties and crystal structure of MgB2 single crystals has been investigated. It has been found that hole doping with Li decreases the superconducting transition temperature Tc, but at a slower rate than electron doping with C or Al. Tc of MgB2 crystals with simultaneou

Uzy Smilansky

Adapting a method developed for the study of quantum chaos on {\it quantum (metric)} graphs \cite {KS}, spectral $ζ$ functions and trace formulae for {\it discrete} Laplacians on graphs are derived. This is achieved by expressing the spectral secular equation in terms of the periodic orbits of the graph, and obtaining functions which belongs to the class of

R J White, H J Rose, S M Bradbury, P Marshall

An eleven channel digital asynchronous transceiver (DAT) employing parallel optical link technology has been developed for trigger signal distribution across the Very Energetic Radiation Imaging Telescope Array System (VERITAS). Combinatorial logic functions are implemented in Xilinx Spartan 3 FPGAs, providing a versatile solution adaptable for use in future

Iwona Karolkiewicz, Aleksandra Nowel, Zbigniew Szafraniec

Let L be an algebraic set and let g : R^(n+1) \times L --> R^(2n) (n is even) be a polynomial mapping such that for each l in L there is r(l)>0 such that the mapping g_l = g(.,l) restricted to the sphere S^n(r) is an immersion for every 0<r<(l), so that the intersection number I(g_l|S^n(r)) is defined. Then the function which maps l in L to I(g_l|S^n(r)) is

A. Gero, E. Akkermans

We study the influence of cooperative effects such as superradiance and subradiance, on the scattering properties of dilute atomic gases. We show that cooperative effects lead to an effective potential between pairs of atoms that decays like $1/r$. In the case of superradiance, this potential is attractive for close enough atoms and can be interpreted as a c

You-gang Feng

We proved that under quantum mechanics a momentum-energy and a space-time are dual vector spaces on an almost complex manifold in position representation, and the minimal uncertainty relations are equivalent to the inner-product relations of their bases. In a microscopic sense, there exist locally a momentum-energy conservation and a space-time conservation.

Kamel Aouiche, Jérôme Darmont

With the wide development of databases in general and data warehouses in particular, it is important to reduce the tasks that a database administrator must perform manually. The idea of using data mining techniques to extract useful knowledge for administration from the data themselves has existed for some years. However, little research has been achieved. T

J. Uglov, V. Schetinin, C. Maple

Noise, corruptions and variations in face images can seriously hurt the performance of face recognition systems. To make such systems robust, multiclass neuralnetwork classifiers capable of learning from noisy data have been suggested. However on large face data sets such systems cannot provide the robustness at a high level. In this paper we explore a pairw

M. Danilov

The CALICE collaboration is presently constructing a test hadron calorimeter (HCAL) with 7620 scintillator tiles read out by novel photo-detectors - Silicon Photomultipliers (SiPMs). This prototype is the first device which uses SiPMs on a large scale. We present the design of the HCAL and report on measured properties of more than 10 thousand SiPMs. We disc

Steven Hurder, Dirk Toeben

We will provide a lower bound for the equivariant Lusternik-Schnirelmann category of an arbitrary proper action in terms of the stratification by orbit types, and an upper bound for proper polar actions in terms of the equivariant Lusternik-Schnirelmann category of its generalized Weyl group. As an application we reprove a theorem of Singhof that determines

Steven Hurder, Dirk Toeben

We study the transverse Lusternik-Schnirelmann category of a Riemannian foliation on a compact manifold. We obtain a necessary and sufficient condition when the transverse LS category is finite. We also introduce a variation on the concept of transverse LS category, the essential transverse category, and show that this is finite for every Riemannian foliatio

J. Kaluzny, I. B. Thompson, S. M. Rucinski, W. Pych

We use photometric and spectroscopic observations of the eclipsing binary OGLEGC-228 (V228) to derive the masses, radii, and luminosities of the component stars. Based on measured systemic velocity, proper motion and distance, the system is a blue straggler member of the globular cluster 47 Tuc. Our analysis shows that V228 is a semi-detached Algol. We obtai

J. Kaluzny, S. M. Rucinski, I. B. Thompson, W. Pych

We use photometric and spectroscopic observations of the detached eclipsing binary V209 omega Cen to derive the masses, radii, and luminosities of the component stars. The system exhibits total eclipses and, based on the measured systemic velocity and the derived distance, is a member of the globular cluster omega Cen. We obtain 0.945 +/- 0.043 Msun, 0.983 +

Berry Schoenmakers, Jilles Tjoelker, Pim Tuyls, Evgeny Verbitskiy

We prove that the average smooth Renyi entropy rate will approach the entropy rate of a stationary, ergodic information source, which is equal to the Shannon entropy rate for a classical information source and the von Neumann entropy rate for a quantum information source.

J. J. He, A. St. J. Murphy

Usage of the Thomas-Ehrman Level Displacement formalism has been examined. Mistakes and inconsistencies are found in several papers, being repeated in subsequent works. Here, we present a complete formalism with a consistent set of definitions. Full algorithms are made available, both as a {\tt FORTRAN} source file and as a user-friendly Visual Basic executa

Jérôme Darmont, Fadila Bentayeb, Omar Boussaïd

We present in this paper a new benchmark for evaluating the performances of data warehouses. Benchmarking is useful either to system users for comparing the performances of different systems, or to system engineers for testing the effect of various design choices. While the TPC (Transaction Processing Performance Council) standard benchmarks address the firs

Zhen He, Jérôme Darmont

In object-oriented or object-relational databases such as multimedia databases or most XML databases, access patterns are not static, i.e., applications do not always access the same objects in the same order repeatedly. However, this has been the way these databases and associated optimisation techniques such as clustering have been evaluated up to now. Thi

Thomas Delzant, Olivier Guichard, François Labourie, Shahar Mozes

We discuss in this article a property of action of groups by isometries called &#34;well displacing&#34;. An action is said to be well displacing, if the displacement function is equivalent to the the displacement function for the action on the Cayley graph. We relate this property with the fact that orbit maps are quasi-isometric embeddings. We first descri

A. Opanowicz

Thermally stimulated luminescence (TSL) and conductivity (TSC) are considered using the classical insulator model that assumes one kind of the active trap, one kind of inactive deep trap, and one kind of the recombination center. Kinetic equations describing the model are solved numerically without and with the use of the quasiequilibrium (QE) approximation.

Frank Gurski

In this paper we consider the problem of computing an mRNA sequence of maximal similarity for a given mRNA of secondary structure constraints, introduced by Backofen et al. in [BNS02] denoted as the MRSO problem. The problem is known to be NP-complete for planar associated implied structure graphs of vertex degree at most 3. In [BFHV05] a first polynomial dy

Lei Liu, Gang Bao, Wei-Tou Ni, D N A Shaul

As ASTROD I travels through space, its test mass will accrue charge due to galactic cosmic-rays and solar energetic particles incident on the spacecraft. This test mass charge will result in Coulomb forces between the test mass and the surrounding electrodes. In earlier work using the GEANT4 toolkit, we predicted a net charging rate of nearly 9.0 +e/s from c

M. Iye, M. Tanaka, M. Yanagisawa, N. Ebizuka

We report the serendipitous findings of 13 faint meteors and 44 artificial space objects by Subaru SuprimeCam imaging observations during 11-16 August 2004. The meteors, at about 100km altitude, and artificial satellites/debris in orbit, at 500km altitude or higher, were clearly discriminated by their apparent defocused image sizes. CCD photometry of the 13

R. Cassano, G. Brunetti, G. Setti, F. Govoni

In this paper we derive new expected scaling relations for clusters with giant radio halos in the framework of the re-acceleration scenario in a simplified, but physically motivated, form, namely: radio power (P_R) vs size of the radio emitting region (R_H), and P_R vs total cluster mass (M_H) contained in the emitting region and cluster velocity dispersion

Valentin Bonzom, Hichem Bouzidi, Pascal Degiovanni

We investigate the behavior of a circuit QED device when the resonator is initially populated with a mesoscopic coherent field. The strong coupling between the cavity and the qubit produces an entangled state involving mesoscopic quasi-pointer states with respect to cavity dissipation. The overlap of the associated field components results in collapse and re

R. J. Vanderbei, N. J. Kasdin, E. Cady

One proposed method for finding terrestrial planets around nearby stars is to use two spacecraft--a telescope and a specially shaped occulter that is specifically designed to prevent all but a tiny fraction of the starlight from diffracting into the telescope. As the cost and observing cadence for such a mission will be driven largely by the separation betwe

Xing-Hao Ye, Qiang Lin

We analyzed the influence of static gravitational field on the vacuum and proposed the concept of inhomogeneous vacuum. According to the corresponding Fermat&#39;s principle in the general relativity, we derived a graded refractive index of vacuum in a static gravitational field. We found that the light deflection in a gravitational field can be calculated c

Arup Banerjee

We investigate the effect of different mass of a Bose- and a Fermi-particle on the collective oscillations of the degenerate boson-fermion mixtures. In particular we consider the monopole and the quadrupole modes of the oscillations and study their characters and the frequencies by using variational-sum-rule approach. We find that for both the modes there ex

Sagar Chakraborty, Partha Guha

In analogy with the load and the metage in hydrodynamics, we define magnetohydrodynamic load and magnetohydrodynamic metage in the case of magnetofluids. They can be used to write the magnetic field in MHD in Clebsch&#39;s form. We show how these two concepts can be utilised to derive the magnetic analogue of the Ertel&#39;s theorem and also, how in the pres

Masafumi Kurachi, Robert Shrock, Koichi Yamawaki

We calculate the Z boson propagator correction, as described by the S parameter, in technicolor theories with extended technicolor interactions included. Our method is to solve the Bethe-Salpeter equation for the requisite current-current correlation functions. Our results suggest that the inclusion of extended technicolor interactions has a relatively small

Ghi R. Shin

We obtain the initial phase space distribution after relativistic heavy ion collision by the CGC shattering method incorporating the uncertainty principle and solve the semi-classical Boltzmann equation which includes the gluon radiation processes. We present as a function of time the attenuation rate of high $p_T$ partons, which have transverse momenta over

S. Ak, S. Bilir, S. Karaali, R. Buser

We present metallicities and their variations with different parameters for 36 high-latitude fields covering Galactic longitudes 0<l<360. The metallicities for relatively short vertical distances (z<2.5 kpc) show systematic fluctuations with Galactic longitude, similar to those of the thick-disc scaleheight, which may be interpreted as indicating a common or

A. A. Ivanov

Model calculations are performed of extensive air shower (EAS) component energies using a variety of hadronic interaction parameters. A conversion factor from electromagnetic component energy to the energy of ultra-high energy cosmic rays (UHECRs) and its model and primary mass dependence is studied. It is shown that model dependence of the factor minimizes

Fulufhelo V. Nelwamondo, Shakir Mohamed, Tshilidzi Marwala

The estimation of missing input vector elements in real time processing applications requires a system that possesses the knowledge of certain characteristics such as correlations between variables, which are inherent in the input space. Computational intelligence techniques and maximum likelihood techniques do possess such characteristics and as a result ar

H. Moradi, A. -C. Donea, C. Lindsey, D. Besliu-Ionescu

We report the discovery of one of the most powerful sunquakes detected to date, produced by an X1.2-class solar flare in active region 10720 on 2005 January 15. We used helioseismic holography to image the source of seismic waves emitted into the solar interior from the site of the flare. Acoustic egression power maps at 3 and 6 mHz with a 2 mHz bandpass rev

Bernd Sturmfels, Jenia Tevelev

Tropical algebraic geometry offers new tools for elimination theory and implicitization. We determine the tropicalization of the image of a subvariety of an algebraic torus under any homomorphism from that torus to another torus.

C. J. Mewton, Z. Ficek

We calculate the radiative properties for a linear dipole-coupled chain of qubits. Using the explicit energy eigenstates of the system, we find the radiation patterns for spontaneous transitions from the one-photon eigenstates to the ground state of the system. We show that depending on the excitation of a specific atom, the radiation tends to be focused eit

Alexander Bolonkin

Author offers and researched the new and revolutionary inflatable electrostatic AB space towers (mast, new space elevator) up to one hundred twenty thousands kilometers (or more) in height. The main innovation is filling the tower by electron gas, which can create pressure up one atmosphere, has negligible small weight and surprising properties. The suggeste

Antonio Pulido Paton

The Astrodynamical Space Test of Relativity using Optical Devices (ASTROD) is a multi-purpose relativity mission concept. ASTROD&#39;s scientific goals are the measurement of relativistic and solar system parameters to unprecedented precision, and the detection and observation of low-frequency gravitational waves to frequencies down to $5\times10^{-6}$ Hz. T

Robert Shrock

We consider a class of theories involving an extension of the Standard Model gauge group to an {\it a priori} arbitrary number of colors, $N_c$, and derive constraints on $N_c$. One motivation for this is the string theory landscape. For two natural classes of embeddings of this $N_c$-extended Standard Model in a supersymmetric grand unified theory, we show

Su Houng Lee, Takumi Doi

We derive the QCD sum rules for the vector and scalar meson mixing in nuclear medium, using a two quark interpolating field for both mesons. Modeling the mixing via a nucleon hole contribution with known coupling constant, the sum rule can be used to determine the overlap of the interpolating field and the scalar meson. In the I=0 channel, we find a stable B

Jian Fu, Xiang Yin, Limin Tong

We propose a two-color scheme of atom guide and 1D optical lattice using evanescent light fields of different transverse modes. The optical waveguide carries a red-detuned light and a blue-detuned light, with both modes far from resonance. The atom guide and 1D optical lattice potentials can be transformed to each other by using a Mach-Zehnder interferometer

Andrey V. Chubukov, Dmitrii L. Maslov

We analyze how the logarithmic renormalizations in the Cooper channel affect the non-analytic temperature dependence of the specific heat coefficient γ(T) - γ(0)=A(T)T in a 2D Fermi liquid. We show that A(T) is expressed exactly in terms of the fully renormalized backscattering amplitude which includes the renormalization in the Cooper channel. In contrast t

S. M. Gonek

We show that if the Riemann Hypothesis is true, then in a region containing most of the right-half of the critical strip, the Riemann zeta-function is well approximated by short truncations of its Euler product. Conversely, if the approximation by products is good in this region, the zeta-function has at most finitely many zeros in it. We then construct a pa

Qun Li, A. J. Wagner

We present a lattice Boltzmann algorithm based on an underlying free energy that allows the simulation of the dynamics of a multicomponent system with an arbitrary number of components. The thermodynamic properties, such as the chemical potential of each component and the pressure of the overall system, are incorporated in the model. We derived a symmetrical

Michael Gronau, Jonathan L. Rosner

When CP asymmetries in $B^0(t)\to π^+ π^-$ are combined using broken flavor SU(3) with decay rates for $B^+\to K^0π^+$ and/or $B^0\to K^+π^-$, one can obtain stringent limits on the weak phase $γ$ which are consistent with those obtained from other CKM constraints. Experimental data in the past few years have improved to the extent that systematic errors ass

Subroto Mukerjee, Cenke Xu, Joel E. Moore

The $s=1$ spinor Bose condensate at zero temperature supports ferromagnetic and polar phases that combine magnetic and superfluid ordering. We investigate the formation of magnetic domains at finite temperature and magnetic field in two dimensions in an optical trap. We study the general ground state phase diagram of a spin-1 system and focus on a phase that

Lutz Petersen

This thesis provides an overview of an approach to quantum simulations using magnesium-25 ions stored in a linear Paul trap as the carriers of quantum information. Their quantum state is manipulated and read out using ultraviolet laser beams. Several important steps towards realising the first experiments have been undertaken, the most striking of which is c

Dean Lee

The symmetric heavy-light ansatz is a method for finding the ground state of any dilute unpolarized system of attractive two-component fermions. Operationally it can be viewed as a generalization of the Kohn-Sham equations in density functional theory applied to N-body density correlations. While the original Hamiltonian has an exact Z_2 symmetry, the heavy-

Paul Martini, John S. Mulchaey, Daniel D. Kelson

We present a study of the distribution of AGN in clusters of galaxies with a uniformly selected, spectroscopically complete sample of 35 AGN in eight clusters at z = 0.06 to 0.31. We find that the 12 AGN with L_X > 10^42 erg/s in galaxies more luminous than a rest-frame M_R < -20 mag are more centrally concentrated than typical cluster galaxies of this lumin

Diana Valencia, Dimitar D. Sasselov, Richard J. O&#39;Connell, ;

The field of extrasolar planets has rapidly expanded to include the detection of planets with masses smaller than that of Uranus. Many of these are expected to have little or no hydrogen and helium gas and we might find Earth analogs among them. In this paper we describe our detailed interior models for a rich variety of such massive terrestrial and ocean pl

Esther Beneish

Let $F$ be an algebraically closed field of characteristic zero, and let $p$ be an odd prime. We show that the center of the generic division algebra of degree $p$ is stably rational over $F$. Equivalently, if we let $V=M_p(F) \oplus M_p(F)$ and $PGL_p$ act on $V$ by simultaneous conjugation, then we show that the function field of the quotient variety $V/PG

Nicolae Angelescu, Robert Minlos, Jean Ruiz, Valentin Zagrebnov

We study the structure of the spectrum of a two-level quantum system weakly coupled to a boson field (spin-boson model). Our analysis allows to avoid the cutoff in the number of bosons, if their spectrum is bounded below by a positive constant. We show that, for small coupling constant, the lower part of the spectrum of the spin-boson Hamiltonian contains (o

Oleg Lunin

We study supersymmetric branes in AdS_7 x S^4 and AdS_4 x S^7. We show that in the former case the membranes should be viewed as M5 branes with fluxes and we identify two types of such fivebranes (they are analogous to giant gravitons and to dual giants). In AdS_4 x S^7 we find both M5 branes with fluxes and freestanding stacks of membranes. We also go beyon

Ingolfur Agustsson, Tereasa G. Brainerd

We investigate the locations of the satellites of relatively isolated host galaxies in the Sloan Digital Sky Survey and the Millennium Run simulation. Provided we use two distinct prescriptions to embed luminous galaxies within the simulated dark matter halos (ellipticals share the shapes of their halos, while disks have angular momenta that are aligned with

Shuchin Aeron, Manqi Zhao, Venkatesh Saligrama

In this paper we address the problem of finding the sensing capacity of sensor networks for a class of linear observation models and a fixed SNR regime. Sensing capacity is defined as the maximum number of signal dimensions reliably identified per sensor observation. In this context sparsity of the phenomena is a key feature that determines sensing capacity.

Jean-Christophe Mauduit, Gary A. Mamon

The environmental influence on the 1.4 GHz continuum radio emission of galaxies is analyzed in a 600 deg2 region of the local Universe containing the Shapley Supercluster (SSC). Galaxies in the FLASH and 6dFGS redshift surveys are cross-identified with NVSS radio sources, selected in a subsample doubly complete in volume and luminosity. Environmental effects

K. G. H. Vollbrecht, J. I. Cirac

The general problem of finding the ground state energy of lattice Hamiltonians is known to be very hard, even for a quantum computer. We show here that this is the case even for translationally invariant systems. We also show that a quantum computer can be built in a 1D chain with a fixed, translationally invariant Hamitonian consisting of nearest--neighbor

E. E. Eyler, D. E. Chieda, Matthew C. Stowe, Michael J. Thorpe

We analyze several possibilities for precisely measuring electronic transitions in atomic helium by the direct use of phase-stabilized femtosecond frequency combs. Because the comb is self-calibrating and can be shifted into the ultraviolet spectral region via harmonic generation, it offers the prospect of greatly improved accuracy for UV and far-UV transiti

Yusuke Sasano

We find a five-parameter family of partial differential systems in two variables with two polynomial Hamiltonians. We give its symmetry and holomorphy conditions. These symmetries, holomorphy conditions and invariant divisors are new.

N. Barnaby, J. M. Cline

We study the possibility of obtaining large nongaussian signatures in the Cosmic Microwave Background in a general class of single-field nonlocal hill-top inflation models. We estimate the nonlinearity parameter f_{NL} which characterizes nongaussianity in such models and show that large nongaussianity is possible. For the recently proposed p-adic inflation

Arnaud Verger, Iacopo Carusotto, Cristiano Ciuti

We present a quantum Monte Carlo study of the quantum correlations in the parametric luminescence from semiconductor microcavities in the strong exciton-photon coupling regime. As already demonstrated in recent experiments, a ring-shaped emission is obtained by applying two identical pump beams with opposite in-plane wavevectors, providing symmetrical signal

Simon Salamon, Jeff Viaclovsky

An orthogonal complex structure on a domain in R^4 is a complex structure which is integrable and is compatible with the Euclidean metric. This gives rise to a first order system of partial differential equations which is conformally invariant. We prove two Liouville-type uniqueness theorems for solutions of this system, and use these to give an alternative

Lars Winther Christensen, Greg Piepmeyer, Janet Striuli, Ryo Takahashi

Let R be a commutative noetherian local ring and consider the set of isomorphism classes of indecomposable totally reflexive R-modules. We prove that if this set is finite, then either it has exactly one element, represented by the rank 1 free module, or R is Gorenstein and an isolated singularity (if R is complete, then it is even a simple hypersurface sing

Bengt Eliasson, Bo Thidé

We have performed a simulation study of Langmuir turbulence in the Earth&#39;s ionosphere by means of a Zakharov model with parameters relevant for the F layer. The model includes dissipative terms to model collisions and Landau damping of the electrons and ions, and a linear density profile, which models the ionospheric plasma inhomogeneity whose length sca

Fernando Marchesano, Waldemar Schulgin

We consider examples of D=4 string theory vacua which, although globally non-geometric, admit a local description in terms of D=10 supergravity backgrounds. We analyze such backgrounds and find that the supersymmetry spinors vary non-trivially along the internal manifold, reproducing the interpolating supergravity solutions found by Frey and Grana. Finally,