September 2007 arXiv papers — page 3
Showing 201–300 of 4,824 papers
François-Xavier Lejeune
Nonparametric density estimation is considered for a discretely observed stationary continuous-time process. For each of three given time sampling procedures either random or deterministic, we establish that histograms and frequency polygons can reach the same optimal $L_{2}$-rates as in the independent and identically distributed case. Moreover, thanks to a
Liang Jiang, Jacob M. Taylor, Anders S. Sørensen, Mikhail D. Lukin
We describe and analyze an efficient register-based hybrid quantum computation scheme. Our scheme is based on probabilistic, heralded optical connection among local five-qubit quantum registers. We assume high fidelity local unitary operations within each register, but the error probability for initialization, measurement, and entanglement generation can be
Yitwah Cheung
In this paper we show that the Hausdorff dimension of the set of singular pairs is 4/3. We also show that the action of diag(e^t,e^t,e^{-2t}) on SL(3,R)/SL(3,Z) admits divergent trajectories that exit to infinity at arbitrarily slow prescribed rates, answering a question of A.N. Starkov. As a by-product of the analysis, we obtain a higher dimensional general
Ebner Pineda, Wilfredo Urbina
In this paper we define Besov-Lipschitz and Triebel-Lizorkin spaces in the context of Gaussian harmonic analysis, the harmonic analysis of Hermite polynomial expansions. We study inclusion relations among them, some interpolation results and continuity results of some important operators (the Ornstein-Uhlenbeck and the Poisson-Hermite semigroups and the Bess
Yuan Wan, Hai-Dong Lv, Hong-Yan Lu, Qiang-Hua Wang
Two scenarios, i.e., the anisotropic s-wave pairing (the s-wave scenario) and the d-wave pairing coexisting with antiferromagnetism (the coexisting scenario) have been introduced to understand some of seemingly s-wave like behaviors in electron doped cuprates. We considered the electronic structure in the presence of a nonmagnetic impurity in the coexistence
Nguyen Duc Minh
Scalar field systems containing higher derivatives are studied and quantized by Hamiltonian path integral formalism. A new point to previous quantization methods is that field functions and their derivatives with time are considered as independent canonical variables. Consequently, generating functional, explicit expressions of propagators and Feynman diagra
S. Dawson, C. B. Jackson
The associated production of a Higgs boson with a b quark is a discovery mode for an MSSM Higgs boson at large tan beta. We compute the SUSY QCD corrections from gluino and squark loops to this process and combine them with the order alpha_s^2 NLO QCD corrections to obtain reliable predictions for the rate. Finally, we compare our results with an effective L
Satoshi Murai
Recently, Nevo introduced the notion of strongly edge decomposable spheres. In this paper, we characterize the algebraic shifted complex of those spheres. Algebraically, this result yields the characterization of the generic initial ideal of the Stanley--Reisner ideal of Gorenstein* complexes having the strong Lefschetz property in characteristic 0.
Efstratios Manousakis
On the basis of the general character and operation of the process of perception, a formalism is sought to mathematically describe the subjective or abstract/mental process of perception. It is shown that the formalism of orthodox quantum theory of measurement, where the observer plays a key role, is a broader mathematical foundation which can be adopted to
Jubin Jose, Alexei Ashikhmin, Phil Whiting, Sriram Vishwanath
The downlink transmission in multi-user multiple-input multiple-output (MIMO) systems has been extensively studied from both communication-theoretic and information-theoretic perspectives. Most of these papers assume perfect/imperfect channel knowledge. In general, the problem of channel training and estimation is studied separately. However, in interference
M. D. Healy
Data taken at the Pierre Auger Observatory are used to search for air showers initiated by ultra-high energy (UHE) photons. Results of searches are reported from hybrid observations where events are measured with both fluorescence and array detectors. Additionally, a more stringent test of the photon fluxes predicted with energies above 10^19 eV is made usin
Stefan Wessel, Norbert Stoop, Emanuel Gull, Simon Trebst
The efficiency of statistical sampling in broad-histogram Monte Carlo simulations can be considerably improved by optimizing the simulated extended ensemble for fastest equilibration. Here we describe how a recently developed feedback algorithm can be generalized to find optimized sampling distributions for the simulation of quantum systems in the context of
Pairing with Unconventional Symmetry around BCS-BEC Crossover: Fermionic Atoms in 2D Optical Lattices to Correlated Electron Systems
cond-mat.supr-conDusan Volcko, Khandker F. Quader
We study superfluid properties of fermions on a 2D lattice using a finite-range pairing interaction derivable from an extended Hubbard model. We obtain signatures of unconventional pair-symmetry states, $d_{x^2-y^2}$ and extended-s ($s^*$), in the BCS-BEC crossover region. The fermion momentum distribution function, $v_k^2$, the ratio of the Bogoliubov coeff
Maryna Nesterenko, Jiri Patera, Dmytro Zhavrotskyj
A symmetric encryption method based on properties of quasicrystals is proposed. The advantages of the cipher are strict aperiodicity and everywhere discontinuous property as well as the speed of computation, simplicity of implementation and a straightforward possibility of extending the method to encryption of higher dimensional data.
Moslem Noori, Masoud Ardakani
Considering a wireless sensor network whose nodes are distributed randomly over a given area, a probability model for the network lifetime is provided. Using this model and assuming that packet generation follows a Poisson distribution, an analytical expression for the complementary cumulative density function (ccdf) of the lifetime is obtained. Using this c
Harvey B. Meyer, John W. Negele
We perform a quenched computation of the glue momentum fraction in the pion. Different discretizations of the gluonic energy-momentum tensor are studied on the lattice for that purpose. We discuss some implications based on the momentum sum rule. Finally we point out promising applications of the techniques developed here.
Taegil Bae, David Adams, Chulwoo Jung, Hyung-Jin Kim
We extend our previous study of taste-symmetry breaking using HYP-smeared staggered fermions in two ways. First, we improve the statistics of a comparison of unimproved and HYP-smeared staggered fermions on quenched lattices with $a\approx 0.1 $fm. This allows us to obtain a signal for all pion tastes, rather than just a subset, and thus to make a complete c
Using Chemistry to Unveil the Kinematics of Starless Cores: Complex Radial Motions in Barnard 68
astro-phSébastien Maret, Edwin A. Bergin, Charles J. Lada
We present observations of 13CO, C18O, HCO+, H13CO+, DCO+ and N2H+ line emission towards the Barnard 68 starless core. The line profiles are interpreted using a chemical network coupled with a radiative transfer code in order to reconstruct the radial velocity profile of the core. Our observations and modeling indicate the presence of complex radial motions,
Georg M. von Hippel, Randy Lewis, Robert G. Petry
The spectrum of masses from a lattice QCD simulation may be found by fitting exponential functions to correlators of operators possessing the quantum numbers of the particles of interest. The ability of evolutionary algorithms to find globally optimized solutions containing a variable number of states across multiple data sets is exploited to provide a promi
Jason K. Johnson, Dmitry M. Malioutov, Alan S. Willsky
We develop a general framework for MAP estimation in discrete and Gaussian graphical models using Lagrangian relaxation techniques. The key idea is to reformulate an intractable estimation problem as one defined on a more tractable graph, but subject to additional constraints. Relaxing these constraints gives a tractable dual problem, one defined by a thin g
Igor Tsukerman
The paper establishes explicit lower bounds for the lattice cell size of periodic structures (metamaterials and photonic crystals) capable of supporting backward waves and producing negative refraction. At optical frequencies, this result implies strong inhomogeneity, in the sense that the cell size cannot be negligible relative to the vacuum wavelength and
Dissociative electron attachment to the H2O molecule. I. Complex-valued potential-energy surfaces for the 2B1, 2A1, and 2B2 metastable states of the water anion
physics.chem-phDaniel J. Haxton, C. W. McCurdy, T. N. Rescigno
We present the results of calculations defining global, three-dimensional representations of the complex-valued potential-energy surfaces of the doublet B1, doublet A1, and doublet B2 metastable states of the water anion that underlie the physical process of dissociative electron attachment to water. The real part of the resonance energies is obtained from c
Oleg Makarenkov
The basic tool of classical results by Malkin and Melnikov on bifurcation of periodic solutions from nondegenerate cycles of autonomous systems with periodic perturbations is an implicit function theorem. In this paper the Poincare index is used to avoid the requirement of nondegeneracity for the unperturbed cycles and to provide additional geometrical prope
F. Castelli, S. Hubrig
UVES spectra of the very young (~10^7 years) peculiar B-type star HR 6000 were analyzed in the near-UV and visual spectral regions (3050-9460 A) with the aim to extend to other spectral ranges the study made previously in the UV using IUE spectra. Stellar parameters Teff=12850K, logg=4.10, and xi=0km/s, as determined from H_beta, H_gamma, H_delta Balmer prof
O. Makarenkov, P. Nistri, D. Papini
In this paper we consider three different synchronization problems consisting in designing a nonlinear feedback unidirectional coupling term for two (possibly chaotic) dynamical systems in order to drive the trajectories of one of them, the slave system, to a reference trajectory or to a prescribed neighborhood of the reference trajectory of the second dynam
Yanling Wu, J. Bernard-Salas, V. Charmandaris, V. Lebouteiller
We present a study of elemental abundances in a sample of thirteen Blue Compact Dwarf (BCD) galaxies, using the $\sim$10--37$μ$m high resolution spectra obtained with Spitzer/IRS. We derive the abundances of neon and sulfur for our sample using the infrared fine-structure lines probing regions which may be obscured by dust in the optical and compare our resu
Vasiliki Pavlidou, Tonia M. Venters
The spectral shape of the unresolved emission from different classes of gamma-ray emitters can be used to disentangle the contributions from these populations to the extragalactic gamma-ray background (EGRB). We present a calculation of the unabsorbed spectral shape of the unresolved blazar contribution to the EGRB starting from the spectral index distributi
Alessandra Buonanno
These lectures are envisioned to be an introductory, basic course in gravitational-wave physics.
Huey-Wen Lin, Robert G. Edwards, Bálint Joó
In this work, we perform parameter tuning with dynamical anisotropic clover lattices using the Schrödinger functional and stout-smearing in the fermion field. We find that $ξ_R/ξ_0$ is relatively close to 1 in our parameter search, which allows us to fix $ξ_0$ in our runs. We proposed to determine the gauge and fermion anisotropy in a Schrödinger-background
Periodic bifurcation from families of periodic solutions for semilinear differential equations with Lipschitzian perturbations in Banach spaces
math.CAMikhail Kamenskii, Oleg Makarenkov, Paolo Nistri
Let A:D(A)\to E be an infinitesimal generator either of an analytic compact semigroup or of a contractive C_0-semigroup of linear operators acting in a Banach space E. In this paper we give both necessary and sufficient conditions for bifurcation of $T$-periodic solutions for the equation x'=Ax+f(t,x)+e g(t,x,e) from a k-parameterized family of T-periodi
Mikhail Kamenskii, Oleg Makarenkov, Paolo Nistri
In this paper we evaluate the topological index of periodic solutions otained via the Malkin-Loud bifurcation result. Incidentally, we do not assume that the perturbation is differentiale.
Triantafyllos Xylouris
Let omega(n) be the number of distinct prime factors dividing n and m > n natural numbers. We calculate a formula showing which prime numbers in which intervals divide a given binomial coefficient. From this formula we get an identity omega(binom(nk)(mk))=sum_i (pi(k/b(i))- pi(k/a(i))) + O(sqrt(k)). Erdoes mentioned that omega(binom(nk)(mk))= log n^n/(m^m (n
B. Deissler, K. J. Hughes, J. H. T. Burke, C. A. Sackett
We demonstrate the effectiveness of a guided-wave Bose-Einstein condensate interferometer for practical measurements. Taking advantage of the large arm separations obtainable in our interferometer, the energy levels of the 87Rb atoms in one arm of the interferometer are shifted by a calibrated laser beam. The resulting phase shifts are used to determine the
Gueorgui Todorov
In this short note we apply methods of Aspinwall-Katz to compute superpotentials of D-branes wrapped on more general obstructed rational curves in Calabi-Yau threefolds. We find an a priori unexpected match between superpotentials from certain such curves and the superpotentials of Landau-Ginzburg models corresponding to minimal models.
Secrecy Capacity Region of a Multi-Antenna Gaussian Broadcast Channel with Confidential Messages
cs.ITRuoheng Liu, H. Vincent Poor
In wireless data networks, communication is particularly susceptible to eavesdropping due to its broadcast nature. Security and privacy systems have become critical for wireless providers and enterprise networks. This paper considers the problem of secret communication over the Gaussian broadcast channel, where a multi-antenna transmitter sends independent c
Muhammad Marwan Muhammad Fuad, Pierre-François Marteau
Similarity search is an important problem in information retrieval. This similarity is based on a distance. Symbolic representation of time series has attracted many researchers recently, since it reduces the dimensionality of these high dimensional data objects. We propose a new distance metric that is applied to symbolic data objects and we test it on time
Consequences of the Gross/Zagier formulae: Stability of average L-values, subconvexity, and non-vanishing mod p
math.NTPhilippe Michel, Dinakar Ramakrishnan
In this paper we investigate some consequences of the Gross/Zagier types of formulae which were introduced by Gross and Zagier, and were then generalized in various directions by Hatcher, Zhang, Kudla and several other people. Working in the classical context of central values of L-series of holomorphic forms of prime level, we deduce an exact average formul
James Day, John Beamish
Superfluidity, liquid flow without friction, is familiar in helium. The first evidence for "supersolidity", its analogue in quantum solids, came from recent torsional oscillator (TO) measurements involving 4-He. At temperatures below 200 mK, TO frequencies increased, suggesting that some of the solid decoupled from the oscillator. This behavior has b
Dung Nguyen, Marcus Spradlin, Anastasia Volovich
Evidence has recently emerged for a hidden symmetry of scattering amplitudes in N=4 super Yang-Mills theory called dual conformal symmetry. At weak coupling the presence of this symmetry has been observed through five loops, while at strong coupling the symmetry has been shown to have a natural interpretation in terms of a T-dualized AdS_5. In this paper we
An asymptotic-numerical approach for examining global solutions to an ordinary differential equation
math.CAMichael Robinson
Purely numerical methods do not always provide an accurate way to find all the global solutions to nonlinear ODE on infinite intervals. For example, finite-difference methods fail to capture the asymptotic behavior of solutions, which might be critical for ensuring global existence. We first show, by way of a detailed example, how asymptotic information alon
Laurent Saminadayar, Pritiraj Mohanty, Richard A. Webb, Pascal Degiovanni
We review recent experimental progress on the saturation problem in metallic quantum wires. In particular, we address the influence of magnetic impurities on the electron phase coherence time. We also present new measurements of the phase coherence time in ultra-clean gold and silver wires and analyse the saturation of \tauphi in these samples, cognizant of
S. M. Gerasyuta, M. A. Durnev
Masses of the lowest multiplets of c,b-mesons in S- and P-wave states with quantum numbers JPC: 0-+, 1--, 0++, 1+-, 1++, 2++ are obtained with the help of dispersion N/D method of heavy quark effective theory. The results are in a good agreement with experimental data. Radiative decay widths for some states mentioned above were calculated.
Nonextensive statistical mechanics and central limit theorems II - Convolution of q-independent random variables
cond-mat.stat-mechSilvio M. Duarte Queiros, Constantino Tsallis
In this article we review recent generalisations of the central limit theorem for the sum of specially correlated (or q-independent) variables, focusing on q greater or equal than 1. Specifically, this kind of correlation turns the probability density function known as q-Gaussian, which emerges upon maximisation of the entropy Sq, into an attractor in probab
D. F. Martinez, Bambi Hu
We study heat transport in transistor-like devices composed of two reservoirs and a gate electrode, with a ballistic electronic one-dimensional system connected between the two reservoirs and interacting with a laser field. We derive in a simple way an equation for the heat flux in terms of the Floquet-Green operator of the system. As a case example, we inve
Stellar Populations Found in the Central kpc of Four Luminous Compact Blue Galaxies at Intermediate Redshift
astro-phC. Hoyos, R. Guzman, A. I. Diaz, D. C. Koo
We investigate the star formation history of the central regions of four Luminous Compact Blue Galaxies (LCBGs). LCBGs are blue (B-V<0.6), compact (MU_B<21.5 mag arcsec^-2) galaxies with absolute magnitudes M_B brighter than -17.5. The LCBGs analyzed here are located at 0.436<z<0.525. They are among the most luminous (M_B < -20.5), blue (B-V < 0.4) and high
Jen-Chi Lee, Yi Yang
We calculate high energy massive scattering amplitudes of closed bosonic string compactified on the torus. We obtain infinite linear relations among high energy scattering amplitudes. For some kinematic regimes, we discover that some linear relations break down and, simultaneously, the amplitudes enhance to power-law behavior due to the space-time T-duality
Nonextensive statistical mechanics and central limit theorems I - Convolution of independent random variables and q-product
cond-mat.softConstantino Tsallis, Silvio M. Duarte Queiros
In this article we review the standard versions of the Central and of the Levy-Gnedenko Limit Theorems, and illustrate their application to the convolution of independent random variables associated with the distribution known as q-Gaussian. This distribution emerges upon extremisation of the nonadditive entropy, basis of nonextensive statistical mechanics.
Jan Van den Bussche
Mining for trees in a graph is shown to be NP-complete.
G. Reiter, A. Shukla, P. M. Platzman, J. Mayers
The momentum distribution in KD2PO4(DKDP) has been measured using neutron Compton scattering above and below the weakly first order paraelectric-ferroelectric phase transition(T=229K). There is very litte difference between the two distributions, and no sign of the coherence over two locations for the proton observed in the paraelectric phase, as in KH2PO4(K
Nawid Zarrabi, Boris Zimmermann, Manuel Diez, Peter Graeber
Erroneous submission in violation of copyright removed by arXiv admin.
Comment on "Is There a "Most Perfect Fluid" Consistent with Quantum Field Theory?"
hep-thD. T. Son
This is a comment on hep-th/0702136
S. Kuru, J. Negro
A class of one dimensional classical systems is characterized from an algebraic point of view. The Hamiltonians of these systems are factorized in terms of two functions that together with the Hamiltonian itself close a Poisson algebra. These two functions lead directly to two time-dependent integrals of motion from which the phase motions are derived algebr
Spectral properties of the non-hermitian Wilson-Dirac operator in the Schroedinger functional
hep-latOliver Witzel, Shinji Takeda, Ulli Wolff
We report on some preparatory investigations for the simulation of the QCD Schroedinger functional with a non-hermitian polynomial hybrid Monte Carlo algorithm. The complex spectrum of the non-hermitean free operator with SF boundary condititons is computed semianalytically. Then it is shown how one can obtain relevant information on the boundary of the spec
Ismaila Dabo, Boris Kozinsky, Nicholas E. Singh-Miller, Nicola Marzari
We address periodic-image errors arising from the use of periodic boundary conditions to describe systems that do not exhibit full three-dimensional periodicity. The difference between the periodic potential, as straightforwardly obtained from a Fourier transform, and the potential satisfying any other boundary conditions can be characterized analytically. I
Leo T. Butler, Vassili Gelfreich
Let T be the nilpotent group of 4 x 4 real upper triangular matrices. In this note we show that the Euler equations of certain left-invariant riemannian metrics on T have a horseshoe. We also show, with the aid of a numerical computation of a Melnikov-type integral, that the Euler equations of the sub-riemannian Carnot metric on T has a horseshoe. This sharp
Hamid Rahmati
We characterize Gorenstein modules over those local rings that admit a finite contracting endomorphism.
Periodic solutions of periodically perturbed planar autonomous systems: A topological approach
math.CAMikhail Kamenskii, Oleg Makarenkov, Paolo Nistri
Aim of this paper is to investigate the existence of periodic solutions of a nonlinear planar autonomous system having a limit cycle x_0 of least period T_0>0 when it is perturbed by a small parameter, T_1-periodic, perturbation. In the case when T_0/T_1 is a rational number l/k, with l, k prime numbers, we provide conditions to guarantee, for the parameter
Georg G. Raffelt, Alexei Yu. Smirnov
Neutrinos streaming off a supernova core transform collectively by neutrino-neutrino interactions, leading to "spectral splits" where an energy E_split divides the transformed spectrum sharply into parts of almost pure but different flavors. We present a detailed description of the spectral split phenomenon which is conceptually and quantitatively un
Two populations are better than one: Short gamma-ray bursts from SGR giant flares and NS-NS mergers
astro-phRobert Chapman, Robert S. Priddey, Nial R. Tanvir
With a peak luminosity of ~10^47 erg/s, the December 27th 2004 giant flare from SGR1806-20 would have been visible by BATSE (the Burst and Transient Source Experiment) out to ~50 Mpc. It is thus plausible that some fraction of the short duration Gamma-Ray Bursts (sGRBs) in the BATSE catalogue were due to extragalactic magnetar giant flares. According to the
Multiparticle SUSY simulations at LHC & ILC: Off-Shell effects, interferences and radiative corrections
hep-phJurgen Reuter
The interesting but difficult phenomenology of supersymmetric models at the LHC and ILC demands a corresponding complexity and maturity from simulation tools. This includes multi-particle final states, reducible and irreducible backgrounds, spin correlations, real emission of photons and gluons, virtual corrections etc. Most of these topics are included in t
Qaisar Shafi, Chin-Aik Lee
We construct supersymmetric SU(4)_C X SU(2)_L X SU(2)_R models with spontaneously broken left-right symmetry (C-parity). The minimal supersymmetric standard model (MSSM) can be recovered at low scales by exploiting the missing partner mechanism. The field content is compatible with realistic fermion masses and mixings, proton lifetime is close to or exceeds
Benjamin Bahr, Thomas Thiemann
This is the second paper concerning gauge-invariant coherent states for Loop Quantum Gravity. Here, we deal with the gauge group SU(2), this being a significant complication compared to the abelian U(1) case encountered in the previous article. We study gauge-invariant coherent states on certain special graphs by analytical and numerical methods. We find tha
Krzysztof M. Graczyk, Jan T. Sobczyk
Different approaches to take into account nonzero lepton mass in the Rein-Sehgal model are compared. Modification of the axial current due to pion pole term are included and it is shown that they lead to large reduction of antineutrino cross section and a change of the shape of $dσ/dQ^2$.
SUSY Associated Vector Coherent States and Generalized Landau Levels Arising From 2-dimensional SUSY
math-phS. Twareque Ali, F. Bagarello
We describe a method for constructing vector coherent states for quantum supersymmetric partner Hamiltonians. The method is then applied to such partner Hamiltonians arising from a generalization of the fractional quantum Hall effect. Explicit examples are worked out.
Jacques Bloch, Tilo Wettig
We have recently given a construction of the overlap Dirac operator at nonzero quark chemical potential. Here, we introduce a quark chemical potential in the domain-wall fermion formalism and show that our earlier result is reproduced if the extent of the fifth dimension is taken to infinity and its lattice spacing is taken to zero. We also extend this resul
I. Guillamon, H. Suderow, S. Vieira, P. Rodiere
We present Scanning Tunneling Spectroscopy measurements at 0.1 K using tips made of Al. At zero field, the atomic lattice and charge density wave of 2HNbSe2 are observed, and under magnetic fields the peculiar electronic surface properties of vortices are precisely resolved. The tip density of states is influenced by the local magnetic field of the vortex, p
Eduardo Follana
We present a determination of the decay constants of the $D$ and $D_s$ mesons from lattice QCD, each with a total error of about 2%, approximately a factor of three better than previous calculations. We have been able to achieve this through the use of a highly improved discretization of QCD for charm quarks, coupled to gauge configurations generated by the
Statistical analysis of neutrino events from SN1987A neutrino burst: estimation of the electron antineutrino mass
astro-phB. I. Goryachev
The method of the statistical sample moments was used for the analysis of neutrino events from SN1987A burst in Cherenkov detectors. In particular the coefficients of correlation $Q(E,t)$ between the energies $E$ of electron antineutrinos $\bar ν_e$ emitted by star and the ejection instants $t$ of $\bar ν_e$ for neutrino events recorded by Cherenkov water de
COMPASS Collaboration, C. Schill
The measurement of transverse spin effects in semi-inclusive deep-inelastic scattering is an important part of the COMPASS physics program. From the analysis of the 2002-2004 data, new results for the transverse target spin asymmetry of z-ordered identified pion and kaon pairs are presented. In addition, a first result for the transverse target spin asymmetr
Leptogenesis with exclusively low-energy CP Violation in the Context of Minimal Lepton Flavour Violation
hep-phSelma Uhlig
We analyze lepton flavour violation (LFV) and the generation of the observed baryon-antibaryon asymmetry of the Universe (BAU) within a generalized minimal lepton flavour violation framework with three quasi-degenerate heavy Majorana neutrinos. The BAU which is obtained through radiative resonant leptogenesis can successfully be generated widely independent
F. Muleri, P. Soffitta, L. Baldini, R. Bellazzini
An X-ray photoelectric polarimeter based on the Gas Pixel Detector has been proposed to be included in many upcoming space missions to fill the gap of about 30 years from the first (and to date only) positive measurement of polarized X-ray emission from an astrophysical source. The estimated sensitivity of the current prototype peaks at an energy of about 3
V. Greco, H. van Hees, R. Rapp
The ultra-relativistic heavy-ion program at RHIC has shown that at intermediate transverse momenta ($p_T \simeq 2$-6 GeV) standard (independent) parton fragmentation can neither describe the observed baryon-to-meson ratios nor the empirical scaling of the hadronic elliptic flow ($v_2$) according to the number of valence quarks. Both aspects find instead a na
H. E. S. S. Collaboration, :, M. Lemoine-Goumard, F. Aharonian
The shell-type supernova remnant RX J0852.0-4622 was detected in 2004 and re-observed between December 2004 and May 2005 with the High Energy Stereoscopic System (H.E.S.S.), an array of four Imaging Cherenkov Telescopes located in Namibia and dedicated to the observations of gamma-rays above 100 GeV. The angular resolution of <0.1 degree and the large field
Benjamin Bahr, Thomas Thiemann
In this paper we investigate the properties of gauge-invariant coherent states for Loop Quantum Gravity, for the gauge group U(1). This is done by projecting the corresponding complexifier coherent states, which have been applied in numerous occasions to investigate the semiclassical limit of the kinematical sector, to the gauge-invariant Hilbert space. This
Christopher J. Conselice
Bulges are a major galaxy component in the nearby universe, and are one of the primary features that differentiates and defines galaxies. The origin of bulges can be directly probed in part by examining distant galaxies to search for high redshift bulges, and to study the properties of bulges in formation. We review the evidence for bulges at high redshift i
D. C. Lin, A. Sharif
The wavelet transform modulus maxima (WTMM) used in the singularity analysis of one fractal function is extended to study the fractal correlation of two multifractal functions. The technique is developed in the framework of joint partition function analysis (JPFA) proposed by Meneveau et al. [1] and is shown to be equally effective. In addition, we show that
G. E. Astrakharchik, Yu. E. Lozovik
Possible signatures of a super-Tonks-Girardeau gas in bosonic systems of trapped quasi-one-dimensional dipoles are discussed at zero temperature. We provide estimation of the frequency of the lowest compressional mode and compare it to analytical results derived using harmonic approach in the high density regime. We construct an exact mapping of the ground-s
W. Benbow, C. Boisson, L. Costamante, O. de Jager
Since 2002 the VHE (>100 GeV) gamma-ray flux of the high-frequency peaked BL Lac PKS 2155-304 has been monitored with the High Energy Stereoscopic System (HESS). An extreme gamma-ray outburst was detected in the early hours of July 28, 2006 (MJD 53944). The average flux above 200 GeV observed during this outburst is ~7 times the flux observed from the Crab N
A. T. Muminov
Quasi-classical picture of motion of spin 1/2 massive particle in a curved spacetime is built on base of simple Lagrangian model. The one is constructed due to analogy with Lagrangian of massive vector particle. Equations of motion and spin propagation coincide with Papapetrou equations describing dynamic of classical spinning particle in a curved spacetime.
J. Gutierrez-Soto, J. Fabregat, J. Suso, M. Lanzara
Context: In preparation for the COROT mission, an exhaustive photometric study of Be stars located in the seismology fields of the COROT mission has been performed. The very precise and long-time-spanned photometric observations gathered by the COROT satellite will give important clues of the origin of the Be phenomenon. Aims: The aim of this work is to find
Olivier Minazzoli, Bertrand Chauvineau
Analytical treatment of time transfer problem for Earth-Satellite system is presented. The development was made in a complete relativistic framework. In accordance with modern clock precision and for low altitude orbits, we neglect the other bodies and consider only the 1/c^2 Earth potential developed up to the J_2 term in spherical harmonics.
Kanchana Limboonsong, Edouard B. Manoukian
The quantum action (dynamical) principle is exploited to investigate the nature and origin of the Faddeev-Popov (FP) factor in gauge theories without recourse to path integrals. Gauge invariant as well as gauge non-invariant interactions are considered to show that the FP factor needs to be modified in more general cases and expressions for these modificatio
HESS Collaboration, W. Benbow, C. Boisson, R. Buehler
Very high energy (VHE; >100 GeV) gamma-ray observations of PG 1553+113 were made with the High Energy Stereoscopic System (HESS) in 2005 and 2006. A strong signal, ~10 standard deviations, is detected by HESS during the 2 years of observations (24.8 hours live time). The time-averaged energy spectrum, measured between 225 GeV to ~1.3 TeV, is characterized by
Multiple stellar populations in Globular Clusters: collection of information from the Horizontal Branch
astro-phF. D'Antona, V. Caloi
The majority of the inhomogeneities in the chemical composition of Globular Cluster (GC) stars appear due to primordial enrichment by hot-CNO cycled material processed in stars belonging to a first stellar generation. Either massive AGB envelopes subject to hot bottom burning, or the envelopes of massive fastly rotating stars could be the progenitors. In bot
Twisted Hopf symmetries of canonical noncommutative spacetimes and the no-pure-boost principle
hep-thGiovanni Amelino-Camelia, Fabio Briscese, Giulia Gubitosi, Antonino Marciano
We study the twisted-Hopf-algebra symmetries of observer-independent canonical spacetime noncommutativity, for which the commutators of the spacetime coordinates take the form [x^{mu},x^{nu}]=i theta^{mu nu} with observer-independent (and coordinate-independent) theta^{mu nu}. We find that it is necessary to introduce nontrivial commutators between transform
HESS Collaboration, W. Benbow, R. Buehler
Very high energy (VHE; >100 GeV) observations of a sample of selected active galactic nuclei (AGN) were performed between January 2005 and April 2007 with the High Energy Stereoscopic System (HESS), an array of imaging atmospheric-Cherenkov telescopes. Significant detections are reported elsewhere for many of these objects. Here, integral flux upper limits f
C. Sivaram, Kenath Arun
There is a lot of current astrophysical evidence and interest in intermediate mass black holes, ranging from a few hundred to several thousand solar masses. The active galaxy M82 and the globular cluster in M31, for example, are known to host such objects. Here we discuss several aspects of intermediate mass black holes such as their expected luminosity, spe
Kurt Langfeld, Gerald Dunne, Holger Gies, Klaus Klingmuller
We propose to apply ``worldline numerics'' to a numerical calculation of quark determinants. The Gross-Neveu model with a U(1) chiral symmetry is considered as a first test. The worldline approach allows for an analytic renormalisation, and only finite parts of the determinant require a numerical calculation. It is shown that the discretisation of th
A. V. Nikolaev, I. V. Bodrenko, E. V. Tkalya
We report results on ab initio calculations of excited states of the fullerene molecule by using configuration interaction (CI) approach with singly excited determinants (SCI). We have used both the experimental geometry and the one optimized by the density functional method and worked with basis sets at the cc-pVTZ and aug-cc-pVTZ level. Contrary to the ear
BaBaR Collaboration, Emmanuel Latour
We present a short review of the measurements of the CKM angle gamma performed by the babar experiment. We focus on methods using charged B decays, which give a direct access to gamma and provide the best constraints so far.
Yousuke Ohyama
We give a basic theory on monodromy evolving deformations. proposed by Chakravarty and Ablowitz in 1996. We show that Halphen's second quadratic system can be described by monodromy evolving deformations. Our result is a generalization of the work on the DH-V system by Chakravarty and Ablowitz.
Sebastian Goette
We generalize Llarull's scalar curvature comparison to Riemannian manifolds admitting metric connections with parallel and alternating torsion and having a nonnegative curvature operator on 2-vectors. As a byproduct, we show that Euler number and signature of such manifolds are determined by their global holonomy representation. Our result holds in parti
New constraints on the Mid-IR EBL from the HESS discovery of VHE gamma rays from 1ES 0229+200
astro-phHESS Collaboration, F. Aharonian
AIMS: To investigate the very high energy (VHE: >100 GeV) gamma-ray emission from the high-frequency peaked BL Lac 1ES 0229+200. METHODS: Observations of 1ES 0229+200 at energies above 580 GeV were performed with the High Energy Stereoscopic System (HESS) in 2005 and 2006. RESULTS: 1ES 0229+200 is discovered by HESS to be an emitter of VHE photons. A signal
R. Frigori, Ch. Gattringer, C. B. Lang, M. Limmer
We present first results for a study with two mass-degenerate dynamical Chirally Improved (CI) fermions on lattices of spatial extent 2.4 fm. The CI Dirac operator obeys the Ginsparg-Wilson condition in good approximation. The pion mass we use is still large O(470 MeV) for the 16**3*32 lattices with lattice spacing of 0.15 fm. The hadron masses are obtained
A. Dziugys, R. Navakas
Processes of mixing and segregation in a packed bed of granular material stirred by a periodically moving rectangular bar are simulated by the discrete element method (DEM). Influence of mechanical properties of the particle material (dynamic friction coefficient, density, elastic modulus) on the segregation intensity is researched. Dynamic friction coeffici
Mikiya Masuda, Dong Youp Suh
We propose some problems on the classification of toric manifolds from the viewpoint of topology and survey related results.
S. A. Petrova
In the average profiles of several radio pulsars, the main pulse is accompanied by the preceding component. This so called precursor is known for its distinctive polarization, spectral, and fluctuation properties. Recent single-pulse observations hint that the sporadic activity at the extreme leading edge of the pulse may be prevalent in pulsars. We for the
F. Mueller, S. Heugel, L. J. Wang
Measuring very small forces, particularly those of a gravitational nature, has always been of great interest, as fundamental tests of our understanding of the physical laws. Ultra-long period mechanical oscillators, typically used in such measurements, will have kT/2 of thermal energy associated with each degree of freedom, owing to the equal-partition of en
W. de Boer, V. Zhukov
Some part of the relic Dark Matter is distributed in small-scale clumps which survived structure formation in inflation cosmological scenario. The annihilation of DM inside these clumps is a strong source of stable charged particles which can have a substantial density near the clump core. The streaming of the annihilation products from the clump can enhance
Light quark masses and pseudoscalar decay constants from Nf=2 Lattice QCD with twisted mass fermions
hep-latB. Blossier, Ph. Boucaud, P. Dimopoulos, F. Farchioni
We present the results of a lattice QCD calculation of the average up-down and strange quark masses and of the light meson pseudoscalar decay constants with Nf=2 dynamical fermions. The simulation is carried out at a single value of the lattice spacing with the twisted mass fermionic action at maximal twist, which guarantees automatic O(a)-improvement of the