May 2006 arXiv papers — page 2

M. Constantinou, H. Panagopoulos, A. Skouroupathis

We study a systematic improvement of perturbation theory for gauge fields on the lattice; the improvement entails resumming, to all orders in the coupling constant, a dominant subclass of tadpole diagrams. This method, originally proposed for the Wilson gluon action, is extended here to encompass all possible gluon actions made of closed Wilson loops; any fe

Jean-Pierre Lees

On behalf of the Babar and Belle collaborations, we report on the measurement of the angle gamma and on the sum of angles 2 beta+gamma of the Unitarity Triangle.

CDF Collaboration

We present the results of a search for standard model Higgs boson production with decay to WW*, identified through the leptonic final states e+ e- nubar nu ,e mu nubar nu and mu+ mu- nubbar nu. This search uses 360 pb-1 of data collected from p pbar collisions at sqrt{s} = 1.96 TeV by the upgraded Collider Detector at Fermilab (CDF II). We observe no signal

Paulo M. Sá, Brigitte Tomé

Recently, it was shown that differential rotation is an unavoidable feature of nonlinear r-modes. We investigate the influence of this differential rotation on the detectability of gravitational waves emitted by a newly born, hot, rapidly-rotating neutron star, as it spins down due to the r-mode instability. We conclude that gravitational radiation may be de

Scott E Pollack, Robin Tuck Stebbins

Over the past few years questions have been raised concerning the use of laser communications links between sciencecraft to transmit phase information crucial to the reduction of laser frequency noise in the LISA science measurement. The concern is that applying medium frequency phase modulations to the laser carrier could compromise the phase stability of t

Scott E Pollack, Robin Tuck Stebbins

The Laser Interferometer Space Antenna (LISA) is being designed to detect and study in detail gravitational waves from sources throughout the Universe such as massive black hole binaries. The conceptual formulation of the LISA space-borne gravitational wave detector is now well developed. The interferometric measurements between the sciencecraft remain one o

Hakan Andreasson

In a previous work \cite{An1} matter models such that the energy density $ρ\geq 0,$ and the radial- and tangential pressures $p\geq 0$ and $q,$ satisfy $p+q\leqΩρ, Ω\geq 1,$ were considered in the context of Buchdahl's inequality. It was proved that static shell solutions of the spherically symmetric Einstein equations obey a Buchdahl type inequality whe

Lau Loi So, James M. Nester, Hsin Chen

We have studied the famous classical pseudotensors in the small region limit, both inside matter and in vacuum. A recent work [Deser et al.1999 CQG 16, 2815] had found one combination of the Einstein and Landau-Lifshitz expressions which yields the Bel-Robinson tensor in vacuum. Using similar methods we found another independent combination of the Bergmann-T

Lau Loi So

Chen and Nester proposed four boundary expressions for the quasilocal quantities using the covariant Hamiltonian formalism. Based on these four expressions, there is a simple generalization that one can consider, so that a two parameter set of boundary expressions can be constructed. Using these modified expressions, a nice result for gravitational energy-mo

U. Schollwoeck, S. R. White

A major advance in density-matrix renormalization group (DMRG) calculations has been achieved by the invention of highly efficient DMRG techniques for the simulation of real-time dynamics of strongly correlated quantum systems in one dimension. Starting from established linear-response techniques in DMRG and early attempts at real-time dynamics, we go on to

M. Kindermann, P. W. Brouwer

We study tunneling of electrons into and between interacting wires in the spin-incoherent regime subject to a magnetic field. The tunneling currents follow power laws of the applied voltage with exponents that depend on whether the electron spins at the relevant length scales are polarized or disordered. The crossover length (or energy) scale is exponential

C. Adelmann, X. Lou, H. -S. Chiang, J. L. Hilton

Electrical spin injection from ferromagnetic $δ$-MnGa into an (Al,Ga)As p-i-n light emitting diode (LED) is demonstrated. The $δ$-MnGa layers show strong perpendicular magnetocrystalline anisotropy, enabling detection of spin injection at remanence without an applied magnetic field. The bias and temperature dependence of the spin injection are found to be qu

Y. Seo, Y. Qin, C. L. Vicente, K. S. Choi

We have studied the effect of perpendicular magnetic fields and temperatures on the nonlinear electronic transport in amorphous Ta superconducting thin films. The films exhibit a magnetic field induced metallic behavior intervening the superconductor-insulator transition in the zero temperature limit. We show that the nonlinear transport in the superconducti

K. Furtado, J. M. Yeomans

We use a lattice Boltzmann method to study pattern formation in chemically reactive binary fluids in the regime where hydrodynamic effects are important. The coupled equations solved by the method are a Cahn-Hilliard equation, modified by the inclusion of a reactive source term, and the Navier-Stokes equations for conservation of mass and momentum. The coupl

G. Seibold, J. Lorenzana, M. Grilli

We systematically investigate charge-ordering phases by means of a restricted and unrestricted Gutzwiller approximation to the single-band Hubbard model with nearest ($t$) and next-nearest neighbor hopping ($t'$). When $|t'/t|$ is small, as appropriate for ${\rm La_{2-x}Sr_xCuO_4}$, stripes are found, whereas in compounds with larger $|t'/t|$ (su

J. -P. Wüstenberg, M. Cinchetti, M. Sánchez Albaneda, M. Bauer

We have studied the possibly half metallic Co2FeSi full Heusler alloy by means of spin- and time-resolved photoemission spectroscopy. For excitation, the second and fourth harmonic of femtosecond Ti:sapphire lasers were used, with photon energies of 3.1 eV and 5.9 eV, respectively. We compare the dependence of the measured surface spin polarization on the pa

S. Trebst, D. A. Huse, E. Gull, H. G. Katzgraber

Competing phases or interactions in complex many-particle systems can result in free energy barriers that strongly suppress thermal equilibration. Here we discuss how extended ensemble Monte Carlo simulations can be used to study the equilibrium behavior of such systems. Special focus will be given to a recently developed adaptive Monte Carlo technique that

T. A. Maier, M. Jarrell, D. J. Scalapino

A dynamic cluster quantum Monte Carlo approximation is used to study the effective pairing interaction of a 2D Hubbard model with a near neighbor hopping $t$ and an on-site Coulomb interaction $U$ . The effective pairing interaction is characterized in terms of the momentum and frequency dependence of the eigenfunction of the leading eigenvalue of the irredu

P. A. Alekseev, J. -M. Mignot, E. V. Nefeodova, K. S. Nemkovski

Mixed-valence phenomena occurring in the "black" (B) and "gold" (G) phases of Sm1-x Yx S have been studied by x-ray diffraction, x-ray absorption spectroscopy, and inelastic neutron scattering. Lattice-constant and phonon-dispersion results confirm that the valence instability occurs already inside the B phase. On the other hand, pronounced t

A. Recati, I. Carusotto, C. Lobo, S. Stringari

The polarization produced by the relative displacement of the potentials trapping two spin species of a dilute Fermi gas with $N_\ua=N_\da$ is calculated at unitarity by assuming phase separation between the superfluid and a spin polarized phase at zero temperature. Due to the energy cost associated with pair breaking, the dipole magnetic polarizability vani

J. Brujic, G. Marty, C. Song, C. Briscoe

Jammed matter is by definition impenetrable to light, rendering the characterization of the 3D geometry difficult. Confocal microscopy of a dyed, refractive index matched emulsion nevertheless allows one to image the jammed system. Here we explain the origin of the mechanism of enhanced fluorescence at the contacts of jammed emulsion droplets in terms of a b

Victor M. Yakovenko

This is a theoretical review of the quantum Hall effect observed in quasi-one-dimensional organic conductors such as (TMTSF)2X. It is written for a book "Physics of Organic Superconductors and Conductors" to be published by Springer and edited by A. G. Lebed.

Anna N. Morozovska, Eugene A. Eliseev, Sergei V. Kalinin

Electromechanical hysteresis loop measurements in Piezoresponse Force Microscopy (Piezoresponse Force Spectroscopy) have emerged as a powerful technique for probing ferroelectric switching behavior on the nanoscale. Interpretation of PFS data requires the relationship between the domain parameters and PFM signal to be established. Here, we analyze the switch

Qing-feng Sun, X. C. Xie, Jian Wang

We investigate the equilibrium property of a mesoscopic ring with spin orbit (SO) interaction. It is well known that for a normal mesoscopic ring threaded by a magnetic flux, the electron acquires a Berry phase that induces the persistent (charge) current. Similarly, the spin of electron acquires a spin Berry phase traversing the ring with SO interaction. It

Yanxia Xing, Qing-feng Sun, Jian Wang

The spin Hall effect in a finite ballistic two-dimensional system with Rashba and Dresselhaus spin-orbit interaction is studied numerically. We find that the spin Hall conductance is very sensitive to the transverse measuring location, the shape and size of the device, and the strength of the spin-orbit interaction. Not only the amplitude of spin Hall conduc

J. S. Andrade, A. D. Araújo, M. Filoche, B. Sapoval

A surprising similarity is found between the distribution of hydrodynamic stress on the wall of an irregular channel and the distribution of flux from a purely Laplacian field on the same geometry. This finding is a direct outcome from numerical simulations of the Navier-Stokes equations for flow at low Reynolds numbers in two-dimensional channels with rough

Saar Rahav, Piet W. Brouwer

If the Ehrenfest time tau_E of a ballistic cavity is not negligible in comparison to its dwell time tau_D, the weak localization correction to the cavity's transmission is suppressed proportional to exp(-tau_E/tau_D). At the same time, quantum interference enhances the probability of reflection into the mode of incidence by a factor two. This `enhanced b

Simon Trebst, Ulrich Schollwoeck, Matthias Troyer, Peter Zoller

We study controlled generation and measurement of superfluid d-wave resonating valence bond (RVB) states of fermionic atoms in 2D optical lattices. Starting from loading spatial and spin patterns of atoms in optical superlattices as pure quantum states from a Fermi gas, we adiabatically transform this state to an RVB state by change of the lattice parameters

E. I. Vorobyov

Motivated by recent observations of plateaus and minima in the radial abundance distributions of heavy elements in the Milky Way and some other spiral galaxies, we propose a dynamical mechanism for the formation of such features around corotation. Our numerical simulations show that the non-axisymmetric gravitational field of spiral density waves generates c

Alicia Berciano Alba, Pedro Borges da Silva, Hans Eichelberger, Francesca Giovacchini

We outline a novel satellite mission concept, DEMON, aimed at advancing our comprehension of both dark matter and dark energy, taking full advantage of two complementary methods: weak lensing and the statistics of galaxy clusters. We intend to carry out a 5000 sqdeg combined IR, optical and X-ray survey with galaxies up to a redshift of z~2 in order to deter

D. -W. Kim, G. Fabbiano, V. Kalogera, A. R. King

We present the first low luminosity (LX > 5 - 10 1036 erg s-1) X-ray luminosity functions (XLFs) of low-mass X-ray binaries (LMXBs) determined for two typical old elliptical galaxies, NGC 3379 and NGC 4278. Because both galaxies contain little diffuse emission from hot ISM and no recent significant star formation (hence no high-mass X-ray binary contaminatio

Manuela Magliocchetti

Combined investigations of the clustering properties of galaxies of different spectral type and high-redshift quasars strongly suggest local ellipticals to be the parent population of optically bright Active Galactic Nuclei (AGN). However, the picture gets more blurred when one extends the analysis to that class of AGNs which show enhanced radio emission. Ob

Martin Lemoine, Guy Pelletier, Benoit Revenu

It is shown that Fermi acceleration at an ultra-relativistic shock wave cannot operate on a particle for more than 1 1/2 Fermi cycle (i.e., u -> d -> u -> d) if the particle Larmor radius is much smaller than the coherence length of the magnetic field on both sides of the shock, as is usually assumed. This conclusion is shown to be in excellent agreement wit

John P. Hughes, Marc Rafelski, Jessica S. Warren, Cara Rakowski

A new Chandra observation of SNR 0506-68.0 (also called N23) reveals a complex, highly structured morphology in the low energy X-ray band and an isolated compact central object in the high energy band. Spectral analysis indicates that the X-ray emission overall is dominated by thermal gas whose composition is consistent with swept-up ambient material. There

Tristan Guillot, Nuno C. Santos, Frédéric Pont, Nicolas Iro

Nine extrasolar planets with masses between 110 and 430M are known to transit their star. The knowledge of their masses and radii allows an estimate of their composition, but uncertainties on equations of state, opacities and possible missing energy sources imply that only inaccurate constraints can be derived when considering each planet separately. Aims: W

Ashley J. Ross, Robert J. Brunner, Adam D. Myers

We present estimates of the N-point galaxy area-averaged angular correlation functions wN for N = 2,...,7 from the third data release of the Sloan Digital Sky Survey (SDSS). The sample was selected from galaxies with 18 < r < 21, and is the largest ever used to study higher-order correlations. The measured wN are used to calculate the projected, sN, and real

G. Miniutti, D. R. Ballantyne, S. W. Allen, A. C. Fabian

We report results from an XMM-Newton observation of the broad-line radio galaxy 3C109 (z=0.3056). Confirming previous results, an Fe emission line is detected, possibly comprising a broad component. However, the data cannot distinguish between an untruncated accretion disc and a case in which the innermost 20-30 gravitational radii are missing. In fact, a pa

Laura Marian, Gary M. Bernstein

We study the ability of weak lensing surveys to detect galaxy clusters and constrain cosmological parameters, in particular the equation of state of dark energy. There are two major sources of noise for weak lensing cluster measurements: the ``shape noise&#39;&#39; from the intrinsic ellipticities of galaxies; and the large scale projection noise. We produce

Jean-Pierre De Villiers

This paper presents a survey of a set of simulations of accretion disks orbiting a rapidly rotating Kerr black hole and embedded in a large-scale initial magnetic field. Each simulation uses a common state for the initial torus, including an MRI seed-field consisting of poloidal loops along isodensity contours, and differ only in the strength of the initial

K. J. Pearson

We review the theory and observations related to the ``superhump&#39;&#39; precession of eccentric accretion discs in close binary sytems. We agree with earlier work, although for different reasons, that the discrepancy between observation and dynamical theory implies that the effect of pressure in the disc cannot be neglected. We extend earlier work that in

V. I. Slysh, V. Migenes

A flare of OH maser emission was discovered in W75N in 2000. Its location was determined with the VLBA to be within 110 au from one of the ultracompact H II regions, VLA2. The flare consisted of several maser spots. Four of the spots were found to form Zeeman pairs, all of them with a magnetic field strength of about 40 mG. This is the highest ever magnetic

L. Clewley, T. D. Kinman

We present evidence for eight new clumps of blue horizontal branch (BHB) stars discovered in a catalogue of these stars compiled from the Sloan Digital Sky Survey (SDSS) by Sirko et al. published in 2004. Clumps are identified by selecting pairs of stars separated by distances <= 2 kpc and with differences in galactocentric radial velocities < 25 km/s. Each

Robert Kimberk, Todd R. Hunter, C. -Y. Edward Tong, Raymond Blundell

A photonic millimeter wave local oscillator capable of producing two microwatts of radiated power at 224 GHz has been developed. The device was tested in one antenna of Smithsonian Institution&#39;s Submillimeter Array (SMA) and was found to produce stable phase on multiple baselines. Graphical data is presented of correlator output phase and amplitude stabi

Matthew W. Muterspaugh, Benjamin F. Lane, Maciej Konacki, B. F. Burke

A new observing mode for the Palomar Testbed Interferometer was developed in2002-2003 which enables differential astrometry at the level of 20 micro-arcseconds for binary systems with separations of several hundred milli-arcseconds (mas). This phase-referenced mode is the basis of the Palomar High-precision Astrometric Search for Exoplanet Systems (PHASES),

T. -H. Lee, L. Stanghellini, R. A. Shaw, B. Balick

As an ongoing study of Magellanic Cloud PNe we have obtained UV spectra of 9 PNe in the SMC to measure their carbon abundances. The spectra have been acquired with ACS HRC/PR200L and SBC/PR130L. The ACS prisms give a reasonable resolution in the range of 1200 -- 2500 A to detect the C IV, C III], and C II] nebular emission, essential for chemical studies of

David S. De Young

Recent x-ray and radio data from radio sources in galaxy clusters are used to show that the pdV work required to inflate the radio lobes exceeds all other energy estimates deduced from the radio emission. If the required jet energy density has an isotropic pressure, then in almost all cases the jet cannot be confined by an external medium. This problem can b

Rychard J. Bouwens, Garth D. Illingworth, Daniel Magee

Today&#39;s deep high resolution multiwavelength surveys contain a wealth of information about galaxies at different epochs. To fully exploit this information, it is useful to be able to produce highly realistic simulations to compare with the observations. Here, we describe one such simulator for producing imaging data for deep galaxy fields. Based upon a p

John M. Fregeau, Shane L. Larson, M. Coleman Miller, Richard O&#39;Shaughnessy

Recent numerical simulations have suggested the possibility of forming double intermediate mass black holes (IMBHs) via the collisional runaway scenario in young dense star clusters. The two IMBHs formed would exchange into a common binary shortly after their birth, and quickly inspiral and merge. Since space-borne gravitational wave (GW) observatories such

Yang Han, Deke Zhao

It is shown that, the quasi-Koszulities of algebras and modules are Morita invariance. A finite-dimensional $K$-algebra $A$ with an action of $G$ is quasi-Koszul if and only if so is the skew group algebra $A \ast G$, where $G$ is a finite group satisfying $\char K \nmid |G|$. A finite-dimensional $G$-graded $K$-algebra $A$ is quasi-Koszul if and only if so

A. V. Belitsky, G. P. Korchemsky, D. Müller

We perform an explicit two-loop calculation of the dilatation operator acting on single trace Wilson operators built from holomorphic scalar fields and an arbitrary number of covariant derivatives in N=2 and N=4 supersymmetric Yang-Mills theories. We demonstrate that its eigenspectrum exhibits double degeneracy of opposite parity eigenstates which suggests t

P. Capel, F. M. Nunes

The sensitivity of elastic breakup to the interior of the projectile wave function is analyzed. Breakup calculations of loosely bound nuclei (8B and 11Be) are performed with two different descriptions of the projectile. The descriptions differ strongly in the interior of the wave function, but exhibit identical asymptotic properties, namely the same asymptot

Joseph Towe

A term in the Maxwell-Ampere law describes a linear displacement current that is symmetrically enclosed by the curl of a magnetic field. In this context symmetry calls for a term in the Faraday-Lenz law, which in the absence of a conducting coil would describe a loop of displacement current about a linear increment of magnetic flux. This term, introduced to

G. A. Gonzalez-Sprinberg, R. Martinez, J. -Alexis Rodriguez

The flavor changing neutral top quark decay t -> c X is computed, where X is a neutral standard model particle, in a extended model with a single extra dimension. The cases for the photon, X= γ$, and a Standard Model Higgs boson, X = H, are analyzed in detail in a non-linear$R_ξgauge. We find that the branching ratios can be enhanced by the dynamics originat

L. Bergamin, D. Grumiller

Frequently it is argued that the microstates responsible for the Bekenstein-Hawking entropy should arise from some physical degrees of freedom located near or on the black hole horizon. In this Essay we elucidate that instead entropy may emerge from the conversion of physical degrees of freedom, attached to a generic boundary, into unobservable gauge degrees

T. S. Morton

A loss in circulation is sometimes cited in connection with bluff-body wakes as a result of comparing the circulation actually observed downstream with a well-known theoretical estimate of the total circulation generated by a cylinder. In an effort to better understand this reported loss in circulation, an alternative estimate of the circulation generated by

R. M. Green

We give a combinatorial construction, not involving a presentation, of almost all untwisted affine Kac--Moody algebras modulo their one-dimensional centres in terms of signed raising and lowering operators on a certain distributive lattice ${\Cal B}$. The lattice ${\Cal B}$ is constructed combinatorially as a set of ideals of a ``full heap&#39;&#39; over the

Mohammed Daoud, Ahmed Jellal

Using a group theory approach, we investigate the basic features of the Landau problem on the Bergman ball {\bf B}^k. This can be done by considering a system of particles living on {\bf B}^k in the presence of an uniform magnetic field B and realizing the ball as the coset space SU(k,1)/U(k). In quantizing the theory on {\bf{B}}^k, we define the wavefunctio

Mohammed Daoud, Ahmed Jellal

We algebraically analysis the quantum Hall effect of a system of particles living on the disc ${\bf B}^1$ in the presence of an uniform magnetic field $B$. For this, we identify the non-compact disc with the coset space $SU(1,1)/U(1)$. This allows us to use the geometric quantization in order to get the wavefunctions as the Wigner ${\cal D}$-functions satisf

Arnau Rios, Artur Polls, Angels Ramos, Herbert Müther

Realistic nucleon-nucleon interaction induce correlations to the nuclear many-body system which lead to a fragmentation of the single-particle strength over a wide range of energies and momenta. We address the question of how this fragmentation affects the thermodynamical properties of nuclear matter. In particular, we show that the entropy can be computed w

M. M. Parish, F. M. Marchetti, A. Lamacraft, B. D. Simons

The two-component Fermi gas is the simplest fermion system displaying superfluidity, and as such finds applications ranging from the theory of superconductivity to QCD. Ultracold atomic gases provide an exceptionally clean realization of this system, where the interatomic interaction and the atom species population are both independent, tuneable parameters.

Fei Zhou

In this Letter we illustrate the possible cyclic fermion pairing states across Feshbach resonances in optical lattices. In cyclic fermion pairing, the pairing amplitude exhibits an oscillatory behavior as the detuning varies. We estimate the quasi-particle gaps in different regimes of the resonances.

Monika Winklmeier, Osanobu Yamada

We investigate the existence of time-periodic solutions of the Dirac equation in the Kerr-Newman background metric. To this end, the solutions are expanded in a Fourier series with respect to the time variable $t$ and the Chandrasekhar separation ansatz is applied so that the question of existence of a time-periodic solution is reduced to the solvability of

K. Hurley, M. S. Briggs, R. M. Kippen, C. Kouveliotou

We present Interplanetary Network (IPN) localization information for 343 gamma-ray bursts observed by the Burst and Transient Source Experiment (BATSE) between the end of the 4th BATSE catalog and the end of the Compton Gamma-Ray Observatory (CGRO) mission, obtained by analyzing the arrival times of these bursts at the Ulysses, Near Earth Asteroid Rendezvous

James T. Ferguson, Ian A. B. Strachan

The superpotential in the Landau-Ginzburg construction of solutions to the Witten-Dijkgraaf-Verlinde-Verlinde (or WDVV) equations is modified to include logarithmic terms. This results in deformations - quadratic in the deformation parameters - of the normal prepotential solution of the WDVV equations. Such solution satisfy various pseudo-quasi-homogeneity c

Alejandro F. Rozenfeld, Sophie Arnaud-Haond, Emilio Hernandez-Garcia, Victor M. Eguiluz

Clonal organisms present a particular challenge in population genetics because, in addition to the possible existence of replicates of the same genotype in a given sample, some of the hypotheses and concepts underlying classical population genetics models are irreconcilable with clonality. The genetic structure and diversity of clonal populations was examine

Marco Matone, Roberto Volpato

We characterize genus g canonical curves by the vanishing of combinatorial products of g+1 determinants of Brill-Noether matrices. This also implies the characterization of canonical curves in terms of (g-2)(g-3)/2 theta identities. A remarkable mechanism, based on a basis of H^0(K_C) expressed in terms of Szego kernels, reduces such identities to a simple r

Serguei Saavedra, Janet Efstathiou, Felix Reed-Tsochas

We analyse the structure and behaviour of a specific voting network using a dynamic structure-based methodology which draws on Q-Analysis and social network theory. Our empirical focus is on the Eurovision Song Contest over a period of 20 years. For a multicultural contest of this kind, one of the key questions is how the quality of a song is judged and how

Peter G. Doyle, Juan Pablo Rossetti

We show that if two closed hyperbolic surfaces (not necessarily orientable or even connected) have the same Laplace spectrum, then for every length they have the same number of orientation-preserving geodesics and the same number of orientation-reversing geodesics. Restricted to orientable surfaces, this result reduces to Huber&#39;s theorem of 1959. Appropr

M. Tumminello, T. Di Matteo, T. Aste, R. N. Mantegna

We investigate the planar maximally filtered graphs of the portfolio of the 300 most capitalized stocks traded at the New York Stock Exchange during the time period 2001-2003. Topological properties such as the average length of shortest paths, the betweenness and the degree are computed on different planar maximally filtered graphs generated by sampling the

M. L. Sadowski, G. Martinez, M. Potemski, C. Berger

Far infrared transmission experiments are performed on ultrathin epitaxial graphite samples in a magnetic field. The observed cyclotron resonance-like and electron-positron-like transitions are in excellent agreement with the expectations of a single-particle model of Dirac fermions in graphene, with an effective velocity of c* = 1.03 x 10^6 m/s.

Ivan G Avramidi

We develop a new method for the calculation of the heat trace asymptotics of the Laplacian on symmetric spaces that is based on a representation of the heat semigroup in form of an average over the Lie group of isometries and obtain a generating function for the whole sequence of all heat invariants.

Gaurav Narain, Jurgen Schaffner-Bielich, Igor N. Mishustin

Compact stars consisting of fermions with arbitrary masses and interaction strengths are studied by solving the structure equation of general relativity, the Tolman-Oppenheimer-Volkoff equations. Scaling solutions are derived for a free and an interacting Fermi gas and tested by numerical calculations. We demonstrate that there is a unique mass-radius relati

M. Pavon Valderrama, E. Ruiz Arriola

We discuss convergence issues as well as short distance constraints on the deuteron wave functions based on chiral perturbation theory relevant to pion deuteron scattering. Non-analytical terms arise in the multiple scattering series for the pion-deuteron scattering length limiting the accuracy of the calculations. This result resembles similar findings in t

Noam Soker, Ehud Behar

We continue to explore the accretion model of the massive binary system eta Carinae by studying the anomalously high He II 4686 line. The line appears just before periastron and disappears immediately thereafter. Based on the He II 4686 line emission from O-stars and their modeling in the literature, we postulate that the He II 4686 line comes from the accel

L. Stawarz, F. Aharonian, S. Wagner, M. Ostrowski

Several BL Lac objects are confirmed sources of variable and strongly Doppler-boosted TeV emission produced in the nuclear portions of their relativistic jets. It is more than probable, that also many of the FR I radio galaxies, believed to be the parent population of BL Lacs, are TeV sources, for which Doppler-hidden nuclear gamma-ray radiation may be only

Myriam Ounaies

We use $L^2$ estimates for the $\bar\partial$ equation to find geometric conditions on discrete interpolating varieties for weighted spaces $A_p(\C)$ of entire functions such that $| f(z)|\le Ae^{Bp(z)}$ for some $A,B>0$. In particular, we give a characterization when $p(z)=e^{| z|}$ and more generally when $\ln p(e^r)$ is convex and $\ln p(r)$ is concave.

Stefan Schmid, Gregor Thalhammer, Klaus Winkler, Florian Lang

We study the horizontal transport of ultracold atoms over macroscopic distances of up to 20 cm with a moving 1D optical lattice. By using an optical Bessel beam to form the optical lattice, we can achieve nearly homogeneous trapping conditions over the full transport length, which is crucial in order to hold the atoms against gravity for such a wide range. F

Lorenzo Iorio

The current bounds on the PPN parameters gamma and beta are of the order of 10^-4-10^-5. Various missions aimed at improving such limits by several orders of magnitude have more or less recently been proposed like LATOR, ASTROD, BepiColombo and GAIA. They involve the use of various spacecraft, to be launched along interplanetary trajectories, for measuring t

D. S. Akerib, E. Aprile, E. A. Baltz, M. R. Dragowsky

A study of the current status of WIMP dark matter searches has been made in the context of scientific and technical planning for a Deep Underground Science and Engineering Laboratory (DUSEL) in the U.S. The table of contents follows: 1. Overview 2. WIMP Dark Matter: Cosmology, Astrophysics, and Particle Physics 3. Direct Detection of WIMPs 4. Indirect Detect

Elena Santopinto, Giuseppe Galata`

A complete classification of $qq \bar q \bar q$ tetraquark states in terms of the spin-flavour, colour and spatial degrees of freedom has been constructed. The permutational symmetry properties of both the spin-flavour and orbital parts of the $qq$ and $\bar{q}\bar{q}$ subsystems are discussed. This complete classification is general and model independent an

Panki Kim, Renming Song

Recently, in [Preprint (2006)], we extended the concept of intrinsic ultracontractivity to nonsymmetric semigroups. In this paper, we study the intrinsic ultracontractivity of nonsymmetric diffusions with measure-valued drifts and measure-valued potentials in bounded domains. Our process $Y$ is a diffusion process whose generator can be formally written as $

Hsiang-nan Li

I discuss some puzzles observed in exclusive $B$ meson decays, concentrating on the large difference between the direct CP asymmetries in the $B^0\to π^\mp K^\pm$ and $B^\pm\to π^0 K^\pm$ modes, the large $B^0\toπ^0π^0$ branching ratio, and the large deviation of the mixing-induced CP asymmetries in the $b\to sq\bar q$ penguins from those in the $b\to c\bar

J. R. Goicoechea, J. Pety, M. Gerin, D. Teyssier

We present 3.65&#39;&#39;x3.34&#39;&#39; angular-resolution IRAM PdBI observations of the CS J=2-1 line toward the Horsehead Photodissociation Region (PDR), complemented with IRAM-30m single-dish observations of several rotational lines of CS, C34S and HCS+. We analyse the CS and HCS+ photochemistry, excitation and radiative transfer to obtain their abundanc

M. A. L. Capri, D. Dudal, J. A. Gracey, V. E. R. Lemes

We continue the study of a local, gauge invariant Yang-Mills action containing a mass parameter, which we constructed in a previous paper starting from the nonlocal gauge invariant mass dimension two operator F_{μν} (D^2)^{-1} F_{μν}. We return briefly to the renormalizability of the model, which can be proven to all orders of perturbation theory by embeddin

A. Abulencia

We describe a measurement of the top quark mass using events with two charged leptons collected by the CDF II detector from $p\bar{p}$ collisions with $\sqrt s = 1.96$ TeV at the Fermilab Tevatron. The likelihood in top mass is calculated for each event by convoluting the leading order matrix element describing $q\bar{q} \to t\bar{t} \to b\ellν_{\ell}\bar{b}

Daniele Guido, Tommaso Isola, Michel L. Lapidus

The definition and main properties of the Ihara zeta function for graphs are reviewed, focusing mainly on the case of periodic simple graphs. Moreover, we give a new proof of the associated determinant formula, based on the treatment developed by Stark and Terras for finite graphs.

Merab Gogberashvili, Alexander S. Sakharov, Edward K. G. Sarkisyan

We argue that in fat brane-world scenarios the light propagating in vacuum will, because of massive ``Kaluza-Klein&#39;&#39; (KK) excitations, experience a refraction. The motion of a photon inside a fat brane can be decomposed in the longitudinal and transverse directions with respect to the surface of the brane. Since the light observable propagation is re

Deok-Sun Lee, Heiko Rieger

The dynamic stability of the Boolean networks representing a model for the gene transcriptional regulation (Kauffman model) is studied by calculating analytically and numerically the Hamming distance between two evolving configurations. This turns out to behave in a universal way close to the phase boundary only for in-degree distributions with a finite seco

Thorsten Renk, Jorg Ruppert

The pattern of angular correlations of hadrons with a (semi-)hard trigger hadron in heavy-ion collisions has attracted considerable interest. In particular, unexpected large angle structures on the away side (opposite to the trigger) have been found. Several explanations have been brought forward, among them Mach shockwaves and Cherenkov radiation. Most of t

Jie Ren, Xiang Wu, Wen-Xu Wang, Guanrong Chen

We study the interplay between evolutionary game and network structure and show how the dynamics of the game affect the growth pattern of the network and how the evolution of the network influence the cooperative behavior in the game. Simulation results show that the payoff-based preferential attachment mechanism leads to the emergence of a scale-free struct

Leslie Ann Goldberg, Mark Jerrum

The Tutte polynomial of a graph G is a two-variable polynomial T(G;x,y) that encodes many interesting properties of the graph. We study the complexity of the following problem, for rationals x and y: take as input a graph G, and output a value which is a good approximation to T(G;x,y). Jaeger, Vertigan and Welsh have completely mapped the complexity of exact

A. Collins, C. J. Hamer, Zheng Weihong

An alternative triplet-wave expansion formalism for dimerized spin systems is presented, a modification of the &#39;bond operator&#39; formalism of Sachdev and Bhatt. Projection operators are used to confine the system to the physical subspace, rather than constraint equations. The method is illustrated for the case of the alternating Heisenberg chain, and c

Pradip Mukherjee, Anirban Saha

An apparent contradiction in the leading order correction to noncommutative (NC) gravity reported in the literature has been pointed out. We show by direct computation that actually there is no such controvarsy and all perturbative NC corrections start from the second order in the NC parameter. The role of symmetries in the vanishing of the first order corre

Victor L. Chernyak

Content : 1) The leading twist pion wave function, 2) &#34;Improved&#34; QCD sum rules with non-local condensates, 3) Pion and kaon form factors and charmonium decays: theory vs experiment, 4) γ^{*}γπ^{o} - form factor, 5) The new non-local axial anomaly, 6) Cross sections γγ--> π^+π^-, K^+K^-, K_S K_S .

M. Schwab, H. Kurtze, T. Auer, T. Berstermann

The light emission of self-assembled (In,Ga)As/GaAs quantum dots embedded in single GaAs-based micropillars has been studied by time-resolved photoluminescence spectroscopy. The altered spontaneous emission is found to be accompanied by a non-exponential decay of the photoluminescence where the decay rate strongly depends on the excitation intensity. A micro

E. Leveque, F. Toschi, L. Shao, J. -P. Bertoglio

A shear-improved Smagorinsky model is introduced based on recent results concerning shear effects in wall-bounded turbulence by Toschi et al. (2000). The Smagorinsky eddy-viscosity is modified subtracting the magnitude of the mean shear from the magnitude of the instantaneous resolved strain-rate tensor. This subgrid-scale model is tested in large-eddy simul

Hao Zheng

In this article, we introduce the notion of cycling operations of arbitrary order in Garside groups, which is a full generalization of the cycling and decycling operations. Theoretically, this notion together with other related concepts provides a context in which various definitions and arguments concerning Garside groups are unified and simplified as well

A. L. Knutsen, A. F. Lopez, R. Muñoz

We introduce a new technique, based on Gaussian maps, to study the possibility, for a given surface, to lie on a threefold as a very ample divisor with given normal bundle. We give several applications, among which one to surfaces of general type and another one to Enriques surfaces. For the latter we prove that any threefold (with no assumption on its singu

Pawel Nurowski

We consider a vector space V over K=R or C, equipped with a skew symmetric bracket [.,.]: V x V --> V and a 2-form omega:V x V --> K. A simple change of the Jacobi identity to the form [A,[B,C]]+[C,[A,B]]+[B,[C,A]]=omega(B,C)A+omega(A,B)C+omega(C,A)B opens new possibilities, which shed new light on the Bianchi classification of 3-dimensional Lie algebras.

S. Leurini, R. Rolffs, S. Thorwirth, B. Parise

Unbiased molecular line surveys are a powerful tool for analyzing the physical and chemical parameters of astronomical objects and are the only means for obtaining a complete view of the molecular inventory for a given source. The present work stands for the first such investigation of a photon-dominated region. The first results of an ongoing millimeter-wav