August 2008 arXiv papers — page 7
Showing 601–700 of 4,272 papers
Greg Brockman, Bill Kay, Emma E. Snively
A universal cycle is a compact listing of a class of combinatorial objects. In this paper, we prove the existence of universal cycles of classes of labeled graphs, including simple graphs, trees, graphs with m edges, graphs with loops, graphs with multiple edges (with up to m duplications of each edge), directed graphs, hypergraphs, and k-uniform hypergraphs
Revisiting an equivalence between maximum parsimony and maximum likelihood methods in phylogenetics
q-bio.PEMareike Fischer, Bhalchandra D. Thatte
Tuffley and Steel (1997) proved that Maximum Likelihood and Maximum Parsimony methods in phylogenetics are equivalent for sequences of characters under a simple symmetric model of substitution with no common mechanism. This result has been widely cited ever since. We show that small changes to the model assumptions suffice to make the two methods inequivalen
A. A. Saharian
Vacuum energy density and stresses are investigated for a scalar field with general curvature coupling parameter in (D+1)-dimensional de Sitter spacetime with an arbitrary number of toroidally compactified spatial dimensions. The corresponding expectation values are presented in the form of the sum of the vacuum expectation values in uncompactified dS spacet
Numerical diagonalization analysis of the criticality of the (2+1)-dimensional XY model: Off-diagonal Novotny's method
cond-mat.stat-mechYoshihiro Nishiyama
The criticality of the (2+1)-dimensional XY model is investigated with the numerical diagonalization method. So far, it has been considered that the diagonalization method would not be very suitable for analyzing the criticality in large dimensions (d \ge 3); in fact, the tractable system size with the diagonalization method is severely restricted. In this p
Walter Bergweiler, Alexandre Eremenko
If the preimage of a four-point set under a meromorphic function belongs to the real line, then the image of the real line is contained in a circle in the Riemann sphere. We include an application of this result to holomorphic dynamics: if the Julia set of a rational function is contained in a smooth curve then it is contained in a circle.
Kunihiro Nagano
Recent progresses of the proton structure measurements and determination of parton distribution functions by $ep$ collisions at HERA are introduced.
S. Beauceron
The Large Hadron Collider (LHC) at CERN in Geneva (Switzerland) will go in operation in the coming months and will soon enable us to analyze the highest energy collisions ever produced at an accelerator. Beyond Standard Model searches at LHC require a detailed understanding of the detector performance, reconstruction algorithms and triggering. Precision meas
Mohan Bhupal, Kaoru Ono
We study symplectic deformation types of minimal symplectic fillings of links of quotient surface singularities. In particular, there are only finitely many symplectic deformation types for each quotient surface singularity.
Wolfgang Lucha, Dmitri Melikhov, Silvano Simula
We present the results of our recent systematic study of the light-cone expansion of heavy-to-light transition form factors in a model with scalar constituents [1]. We show that the higher-twist contributions (represented in this model by off-light-cone effects) all have the same behaviour in the 1/m_Q expansion. The suppression parameter of the higher-twist
Ivar Ekeland, Ali Lazrak
This paper characterizes differentiable and subgame Markov perfect equilibria in a continuous time intertemporal decision problem with non-constant discounting. Capturing the idea of non commitment by letting the commitment period being infinitesimally small, we characterize the equilibrium strategies by a value function, which must satisfy a certain equatio
T. Tzen Ong, B. A. Jones
We have studied the antiferromagnetic quantum phase transition of a 2D Kondo-Heisenberg square lattice using the non-linear sigma model. A renormalization group analysis of the competing Kondo -- RKKY interaction was carried out to 1-loop order in the $ε$ expansion, and a new quantum critical point is found, dominated by Kondo fluctuations. In addition, the
Gavril Giurgiu
The CDF detector at Fermilab has accumulated more that 3/fb of data which enables unprecedented studies of heavy flavor hadron properties. We present recent CDF measurements of mass and lifetime of the Bc meson as well as lifetime, mixing and CP violation properties of Bs mesons.
ZEUS Collaboration, S. Chekanov
Three-jet production in deep inelastic ep scattering and photoproduction was investigated with the ZEUS detector at HERA using an integrated luminosity of 127 pb-1. Measurements of differential cross sections are presented as functions of angular correlations between the three jets in the final state and the proton-beam direction. These correlations provide
Mieczyslaw K. Dabkowski, Maciej Mroczkowski
We introduce diagrams and Reidemeister moves for links in FxS^{1}, where F is an orientable surface. Using these diagrams we compute (in a new way) the Kauffman Bracket Skein Modules (KBSM) for D^{2}xS^{1} and AxS^{1}, where D^{2} is a disk and A is an annulus. Moreover, we also find the KBSM for the F_{0,3}xS^{1}, where F_{0,3} denotes a disk with two holes
K. -I. Nishikawa, Y. Mizuno, P. Hardee, H. Sol
Nonthermal radiation observed from astrophysical systems containing relativistic jets and shocks, e.g., gamma-ray bursts (GRBs), active galactic nuclei (AGNs), and Galactic microquasar systems usually have power-law emission spectra. Recent PIC simulations of relativistic electron-ion (electron-positron) jets injected into a stationary medium show that parti
Qingjuan Yu, Youjun Lu
Growth of massive black holes (MBHs) in galactic centers comes mainly from gas accretion during their QSO/AGN phases. In this paper we apply an extended Soltan argument, connecting the local MBH mass function with the time-integral of the QSO luminosity function, to the demography of MBHs and QSOs from recent optical and X-ray surveys, and obtain robust cons
Observational evidence of CMEs interacting in the inner heliosphere as inferred from MHD simulations
physics.space-phN. Lugaz, W. B. Manchester, I. I. Roussev, T. I. Gombosi
The interaction of multiple Coronal Mass Ejections (CMEs) has been observed by LASCO coronagraphs and by near-Earth spacecraft, and it is thought to be an important cause of geo-effective storms, large Solar Energetic Particles events and intense Type II radio bursts. New and future missions such as STEREO, the LWS Sentinels, and the Solar Orbiter will provi
Dominik A. Riechers, Fabian Walter, Christopher L. Carilli, Frank Bertoldi
We present high-resolution Very Large Array imaging of the molecular gas in the host galaxy of the high redshift quasar BRI 1335-0417 (z=4.41). Our CO(2-1) observations have a linear resolution of 0.15" (1.0 kpc) and resolve the molecular gas emission both spatially and in velocity. The molecular gas in BRI 1335-0417 is extended on scales of 5 kpc, and s
Louis E. Strigari, James S. Bullock, Manoj Kaplinghat, Joshua D. Simon
The Milky Way has at least twenty-three known satellite galaxies that shine with luminosities ranging from about a thousand to a billion times that of the Sun. Half of these galaxies were discovered in the past few years in the Sloan Digital Sky Survey, and they are among the least luminous galaxies in the known Universe. A determination of the mass of these
Cody Raskin, Evan Scannapieco, James Rhoads, Massimo Della Valle
We carry out a comprehensive theoretical examination of the relationship between the spatial distribution of optical transients and the properties of their progenitor stars. By constructing analytic models of star-forming galaxies and the evolution of stellar populations within them, we are able to place constraints on candidate progenitors for core-collapse
Could deformed special relativity naturally arise from the semiclassical limit of quantum gravity?
hep-thLee Smolin
A argument is described for how deformed or doubly special relativity may arise in the semiclassical limit of a quantum theory of gravity. We consider a generic quantum theory of gravity coupled to matter, from which we use only the assumption that a Hamiltonian constraint is imposed. We study circumstances in which Lambda, G and hbar all may be separately n
David Conlon, Jacob Fox, Benny Sudakov
The Ramsey number r_k(s,n) is the minimum N such that every red-blue coloring of the k-tuples of an N-element set contains either a red set of size s or a blue set of size n, where a set is called red (blue) if all k-tuples from this set are red (blue). In this paper we obtain new estimates for several basic hypergraph Ramsey problems. We give a new upper bo
Yaakov S. Weinstein, Winton G. Brown, Lorenza Viola
Pseudorandom circuits generate quantum states and unitary operators which are approximately distributed according to the unitarily invariant Haar measure. We explore how several design parameters affect the efficiency of pseudo-random circuits, with the goal of identifying relevant trade-offs and optimizing convergence. The parameters we explore include the
Piotr Milos
We consider a branching system consisting of particles moving according to a Markov family in $\Rd$ and undergoing subcritical branching with a constant rate $V>0$. New particles immigrate to the system according to homogeneous space-time Poisson random field. The process of the fluctuations of the rescaled occupation time is studied with very mild assumptio
B. Geyer, G. L. Klimchitskaya, V. M. Mostepanenko
The thermal Casimir effect in ideal metal rectangular boxes is considered using the method of zeta functional regularization. The renormalization procedure is suggested which provides the finite expression for the Casimir free energy in any restricted quantization volume. This expression satisfies the classical limit at high temperature and leads to zero the
Hilbert-Chow morphism for non commutative Hilbert schemes and moduli spaces of linear representations
math.AGFederica Galluzzi, Francesco Vaccarino
Let $k$ be a commutative ring and let $R$ be a commutative $k-$algebra. The aim of this paper is to define and discuss some connection morphisms between schemes associated to the representation theory of a (non necessarily commutative) $R-$algebra $A. $ We focus on the scheme $\ran//\GL_n$ of the $n-$dimensional representations of $A, $ on the Hilbert scheme
Toru Kojo, Daisuke Jido
The 1/$N_c$ arguments are developed to classify the hadronic states in the correlators. Arguments applied to the $σ$ meson correlator enable to separate the instanton, glueball, and, in particular, the $ππ$ scattering states by $1/N_c$ from both 2q and 4q correlators. The bare resonance pole with no mixing effects are analyzed with the QCD sum rules (QSR). T
Sotirios Sabanis
This paper presents the general form and essential properties of the q-optimal measure following the approach of Delbaen and Schachermayer (1996) and proves its existence under mild conditions. Most importantly, it states a necessary and sufficient condition for a candidate measure to be the q-optimal measure in the case even of signed measures. Finally, an
The emergence of coherent magnetic excitations in the pseudogap phase of La2-xSrxCuO4
cond-mat.supr-conO. J. Lipscombe, B. Vignolle, T. G. Perring, C. D. Frost
We use inelastic neutron scattering to measure the magnetic excitations in the underdoped superconductor La2-xSrxCuO4 (x=0.085, Tc=22 K) over energy and temperatures ranges 5 < E < 200 meV and 5 < T < 300 K respectively. At high temperature (T = 300 K), we observe strongly damped excitations with a characteristic energy scale of approximately 50 meV. As the
M. M. Qazilbash, J. J. Hamlin, R. E. Baumbach, M. B. Maple
We present the first infrared and optical study in the normal state of ab-plane oriented single crystals of the iron-oxypnictide superconductor LaFePO. We find that this material is a low carrier density metal with a moderate level of correlations and exhibits signatures of electron-boson coupling. The data is consistent with the presence of coherent quasipa
S. F. King, R. Luo, D. J. Miller, R. Nevzorov
We discuss flavour dependent lepton asymmetries in the Exceptional Supersymmetric Standard Model (E$_6$SSM). In the E$_6$SSM, the right-handed neutrinos do not participate in gauge interactions, and they decay into leptons and leptoquarks. Their Majorana nature allows violation of lepton number. New particles and interactions can result in substantial lepton
Asymptotic behavior of eigenvalues of Schrödinger type operators with degenerate kinetic energy
math.SPChristian Hainzl, Robert Seiringer
We study the eigenvalues of Schrödinger type operators $T + λV$ and their asymptotic behavior in the small coupling limit $λ\to 0$, in the case where the symbol of the kinetic energy, $T(p)$, strongly degenerates on a non-trivial manifold of codimension one.
J. Spinelly, E. R. Bezerra de Mello
In this paper we investigate vacuum polarization effects associated with charged massive quantum fermionic fields in a six-dimensional cosmic string space-times considering the presence of a magnetic flux running along its core. We have shown that for specific values of the parameters which codify the presence of the cosmic string, and the fractional part of
K. A. Al-Hassanieh, C. D. Batista, P. Sengupta, A. E. Feiguin
We derive a Kondo Lattice model with a correlated conduction band from a two-band Hubbard Hamiltonian. This mapping allows us to describe the emergence of a robust pairing mechanism in a model that only contains repulsive interactions. The mechanism is due to topological confinement and results from the interplay between antiferromagnetism and delocalization
Non-uniform sampling, image recovery from sparse data and the discrete sampling theorem
physics.opticsLeonid P. Yaroslavsky, Gil Shabat, Benny G. Salomon, Ianir A. Ideses
In many applications sampled data are collected in irregular fashion or are partly lost or unavailable. In these cases it is required to convert irregularly sampled signals to regularly sampled ones or to restore missing data. In this paper, we address this problem in a framework of a discrete sampling theorem for band-limited discrete signals that have a li
Joseph C. Weingartner
In interstellar dust grains, internal processes dissipate rotational kinetic energy. The dissipation is accompanied by thermal fluctuations, which transfer energy from the vibrational modes to rotation. Together, these processes are known as internal relaxation. For the past several years, internal relaxation has been thought to give rise to thermal flipping
Soko Matsumura, Genya Takeda, Fred Rasio
Strong tidal interaction with the central star can circularize the orbits of close-in planets. With the standard tidal quality factor Q of our solar system, estimated circularization times for close-in extrasolar planets are typically shorter than the ages of the host stars. While most extrasolar planets with orbital radii a < 0.1 AU indeed have circular orb
R. Hirschi, U. Frischknecht, F. -K. Thielemann, M. Pignatari
Massive stars played a key role in the early evolution of the Universe. They formed with the first halos and started the re-ionisation. It is therefore very important to understand their evolution. In this paper, we describe the strong impact of rotation induced mixing and mass loss at very low $Z$. The strong mixing leads to a significant production of prim
Jérôme Pety, Robert Lucas, Harvey S. Liszt
To understand the environment and extended structure of the host galactic gas whose molecular absorption line chemistry, we previously observed along the microscopic line of sight to the blazar/radiocontinuum source NRAO150 (aka B0355+508), we used the IRAM 30m Telescope and Plateau de Bure Interferometer to make two series of images of the host gas: i) 22.5
O. Costin, G. Luo, S. Tanveer
We consider the 3-D Navier-Stokes initial value problem, $$ v_t - νΔv = -\mathcal{P} [ v \cdot \nabla v ] + f , v(x, 0) = v_0 (x), x \in \mathbb{T}^3 (*) $$ where $\mathcal{P}$ is the Hodge projection. We assume that the Fourier transform norms $ \| {\hat f} \|_{l^1 (\mathbb{Z}^3)}$ and $\| {\hat v}_0 \|_{l^{1} (\mathbb{Z}^3)}$ are finite. Using an inverse L
H. -J. Grimm, J. McDowell, G. Fabbiano, M. Elvis
We present a system of X-ray photometry for the Chandra satellite. X-ray photometry can be a powerful tool to obtain flux estimates, hardness ratios, and colors unbiased by assumptions about spectral shape and independent of temporal and spatial changes in instrument characteristics. The system we have developed relies on our knowledge of effective area and
Victor van Reijswoud, Arjan de Jager
Development organizations and International Non-Governmental Organizations have been emphasizing the high potential of Free and Open Source Software for the Less Developed Countries. Cost reduction, less vendor dependency and increased potential for local capacity development have been their main arguments. In spite of its advantages, Free and Open Source So
Precipitate stability and recrystallisation in the weld nuggets of friction stir welded Al-Mg-Si and Al-Mg-Sc alloys
cond-mat.mtrl-sciXavier Sauvage, Anite Dédé, Alexandra Cabello Muñoz, Bertrand Huneau
Two different precipitate hardening aluminium alloys processed by friction stir welding were investigated. The microstructure and the hardness of the as delivered materials were compared to that of the weld nugget. Transmission electron microscopy observations combined with three-dimensional atom probe analyses clearly show that β;" precipitates dissolve
Nanostructure and related mechanical properties of an Al-Mg-Si alloy processed by severe plastic deformation
cond-mat.mtrl-sciGulnaz Nurislamova, Xavier Sauvage, Maxim Murashkin, Rinat Islamgaliev
Microstructural features and mechanical properties of an Al-Mg-Si alloy processed by high-pressure torsion have been investigated using transmission electron microscopy, X-ray diffraction, three-dimensional atom probe, tensile tests and microhardness measurements. It is shown that HPT processing of the Al-Mg-Si alloy leads to a much stronger grain size refin
Nulling interferometry: performance comparison between space and ground-based sites for exozodiacal disc detection
astro-phD. Defrère, O. Absil, V. Coudé du Foresto, W. C. Danchi
Characterising the circumstellar dust around nearby main sequence stars is a necessary step in understanding the planetary formation process and is crucial for future life-finding space missions such as ESA's Darwin or NASA's Terrestrial Planet Finder (TPF). Besides paving the technological way to Darwin/TPF, the space-based infrared interferometers
H. van Hees, M. Mannarelli, Vincenzo Greco, Ralf Rapp
We assess transport properties of heavy quarks in the Quark-Gluon Plasma (QGP) using static heavy-quark (HQ) potentials from lattice-QCD calculations in a Brueckner many-body T-matrix approach to evaluate elastic heavy-quark-light-quark scattering amplitudes. In the attractive meson and diquark channels resonance states are formed for temperatures up to ~1.5
Entanglement dynamics and Bell Violations of two atoms in Tavis-Cummings model with phase decoherence
quant-phC. J. Shan, W. W. Cheng, T. K. Liu, D. J. Guo
Considering the dipole-dipole coupling intensity between two atoms and the field in the Fock state, the entanglement dynamics between two atoms that are initially entangled in the system of two two-level atoms coupled to a single mode cavity in the presence of phase decoherence has been investigated. The two-atom entanglement appears with periodicity without
M. Bender, G. F. Bertsch, P. -H. Heenen
Mass differences are an often used as signature and measure for shell closure. Using the angular-momentum projected Generator Coordinate Method and the Skyrme interaction SLy4, we analyze the modification of mass differences due to static deformation and dynamic fluctuations around the mean-field ground state.
Theory of the nonsteady diffusion growth of a gas bubble in a supersaturated solution of gas in liquid
cond-mat.stat-mechA. P. Grinin, F. M. Kuni, G. Yu. Gor
Using a self-similar approach a general nonsteady theory is elaborated for the case of the diffusion growth of a gas bubble in a supersaturated solution of gas in liquid. Due to the fact that the solution and the bubble in it are physically isolated, the self-similar approach accounts for the balance of the number of gas molecules in the solution and in the
Georg Heinrich, F. K. Wilhelm
Intrinsic noise is known to be ubiquitous in Josephson junctions. We investigate a voltage biased superconducting tunnel junction including a very small number of pinholes - transport channels possessing a transmission coefficient close to unity. Although few of these pinholes contribute very little to the conductance, they can dominate current fluctuations
R. J. A. Hill, L. Eaves
The shape of a weightless spinning liquid droplet is governed by the balance between the surface tension and centrifugal forces. The axisymmetric shape for slow rotation becomes unstable to a non-axisymmetric distortion above a critical angular velocity, beyond which the droplet progresses through a series of 2-lobed shapes. Theory predicts the existence of
Adrian Tanasa
We make here a short overview of the recent developments regarding translation-invariant models on the noncommutative Moyal space. A scalar model was first proposed and proved renormalizable. Its one-loop renormalization group flow and parametric representation were calculated. Furthermore, a mechanism to take its commutative limit was recently given. Finall
Ganpathy Murthy, Subir Sachdev
We describe a new phase transition of the bilayer quantum Hall ferromagnet at filling fraction $ν= 1$. In the presence of static disorder (modeled by a periodic potential), bosonic $S=1/2$ spinons can undergo a superfluid-insulator transition while preserving the ferromagnetic order. The Mott insulating phase has an emergent U(1) photon, and the transition i
Kourosh Nozari, Mahin Pourghasemi
We study possible crossing of the phantom divide line in a DGP-inspired $F(R,ϕ)$ braneworld scenario where scalar field and curvature quintessence are treated in a unified framework. With some specific form of $F(R,ϕ)$ and by adopting a suitable ansatz, we show that there are appropriate regions of the parameters space which account for late-time acceleratio
M. Klasen, G. Kramer
We confront the latest H1 and ZEUS data on diffractive dijet photoproduction with next-to-leading order QCD predictions in order to determine whether a rapidity gap survival probability of less than one is supported by the data. We find evidence for this hypothesis when assuming global factorization breaking for both the direct and resolved photon contributi
Casey Blood
Quantum mechanics gives many versions of reality but we perceive only one. One potential explanation for this, the one considered here, is that the wave function collapses down to just one version. The experimental situation is briefly reviewed, with no evidence found for collapse. The theoretical position is also reviewed and found wanting. Collapse-by-obse
Planning Curricular Proposals on Sound and Music with Prospective Secondary-School Teachers
physics.ed-phErica Bisesi, Marisa Michelini
Sound is a preferred context to build foundations on wave phenomena, one of the most important disciplinary referents in physics. It is also one of the best-set frameworks to achieve transversality, overcoming scholastic level and activating emotional aspects which are naturally connected with every day life, as well as with music and perception. Looking at
Xavier Grehant, J. M. Dana
Platform virtualization helps solving major grid computing challenges: share resource with flexible, user-controlled and custom execution environments and in the meanwhile, isolate failures and malicious code. Grid resource management tools will evolve to embrace support for virtual resource. We present two open source projects that transparently supply virt
Massimo Giovannini
Recent analyses of the WMAP 5-year data constrain possible non-adiabatic contributions to the initial conditions of CMB anisotropies. Depending upon the early dynamics of the plasma, the amplitude of the entropic modes can experience a different suppression by the time of photon decoupling. Explicit examples of the latter observation are presented both analy
Mirela Babalic, Niclas Wyllard
We study the relation between the kappa-symmetric formulation of the supermembrane in eleven dimensions and the pure-spinor version. Recently, Berkovits related the Green-Schwarz and pure-spinor superstrings. In this paper, we attempt to extend this method to the supermembrane. We show that it is possible to reinstate the reparameterisation constraints in th
C. J. Shan, J. B. Liu, W. W. Cheng, T. K. Liu
In this paper, we study entanglement dynamics of a two-qubit extended Werner-like state locally interacting with independent noisy channels, i.e., amplitude damping, phase damping and depolarizing channels. We show that the purity of initial entangled state has direct impacts on the entanglement robustness in each noisy channel. That is, if the initial entan
Georg Knebel, Dai Aoki, Jean-Pascal Brison, Jacques Flouquet
The pressure--temperature phase diagram of CeRhIn_5 has been studied under high magnetic field by resistivity measurements. Clear signatures of a quantum critical point has been found at a critical pressure of p_c = 2.5 GPa. The field induced magnetic state in the superconducting state is stable up to the highest field. At p_c the antiferromagnetic ground-st
Entanglement and quantum phase transition in alternating XY spin chain with next-nearest neighbour interactions
quant-phC. J. Shan, W. W. Cheng, T. K. Liu, Y. X. Huang
By using the method of density-matrix renormalization-group to solve the different spin-spin correlation functions, the nearest-neighbouring entanglement(NNE) and next-nearest-neighbouring entanglement(NNNE) of one-dimensional alternating Heisenberg XY spin chain is investigated in the presence of alternating nearest neighbour interactions of exchange coupli
Mykhailo Potomkin
System of partial differential equations with a convolution terms and non-local nonlinearity describing oscillations of plate due to Berger approach and with accounting for thermal regime in terms of Coleman-Gurtin and Gurtin-Pipkin law and fading memory of material is considered. The equation is transformed into a dynamical system in a suitable Hilbert spac
The entanglement in one-dimensional random XY spin chain with Dzyaloshinskii-Moriya interaction
quant-phC. J. Shan, W. W. Cheng, T. K. Liu, Y. X. Huang
The impurities of exchange couplings, external magnetic fields and Dzyaloshinskii--Moriya (DM) interaction considered as Gaussian distribution, the entanglement in one-dimensional random $XY$ spin systems is investigated by the method of solving the different spin-spin correlation functions and the average magnetization per spin. The entanglement dynamics at
Two effects relevant for the study of astrophysical reaction rates: gamma transitions in capture reactions and Coulomb suppression of the stellar enhancement
nucl-thT. Rauscher
Nucleosynthesis processes involve reactions on several thousand nuclei, both close to and far off stability. The preparation of reaction rates to be used in astrophysical investigations requires experimental and theoretical input. In this context, two interesting aspects are discussed: (i) the relevant gamma transition energies in astrophysical capture react
Mean-field dynamics of a two-mode Bose-Einstein condensate subject to noise and dissipation
cond-mat.otherF. Trimborn, D. Witthaut, S. Wimberger
We discuss the dynamics of an open two-mode Bose-Hubbard system subject to phase noise and particle dissipation. Starting from the full many-body dynamics described by a master equation the mean-field limit is derived resulting in an effective non-hermitian (discrete) Gross-Pitaevskii equation which has been introduced only phenomenologically up to now. The
C. J. Shan, W. W. Cheng, T. K. Liu, Y. X. Huang
The entanglement in one-dimensional random XY spin systems where the impurities of exchange couplings and the external magnetic fields are considered as random variables is investigated by solving the different spin-spin correlation functions and the average magnetization per spin. The entanglement dynamics near particular locations of the system is also stu
AGILE detection of variable gamma-ray activity from the blazar S5 0716+714 during September-October 2007
astro-phF. D'Ammando, A. W. Chen, M. Villata, C. M. Raiteri
We report the gamma-ray activity from the Intermediate BL Lac S5 0716+714 during 2007 September-October observations by the AGILE satellite, coincident with a period of intense optical activity of the source monitored by GASP-WEBT. AGILE observed the source with its two co-aligned imagers, the Gamma-Ray Imaging Detector (GRID) and the hard X-ray imager (Supe
Tanju Gleisberg, Stefan Hoeche, Frank Krauss
Different methods for the calculation of cross sections with many QCD particles are compared. To this end, CSW vertex rules, Berends-Giele recursion and Feynman-diagram based techniques are implemented as well as various methods for the treatment of colours and phase space integration. We find that typically there is only a small window of jet multiplicities
Doping evolution of the electronic specific heat coefficient in slightly-doped La2-xSrxCuO4 single crystals
cond-mat.supr-conSeiki Komiya, I. Tsukada
Detailed doping dependence of the electronic specific heat coefficient gamma is studied for La2-xSrxCuO4 (LSCO) single crystals in the slightly-doped regime. We find that gamma systematically increases with doping, and furthermore, even for the samples in the antiferromagnetic (AF) regime, gamma already acquires finite value and grows with x. This suggests t
D. Koudela, A. -M. Uimonen, H. Häkkinen
We study the dependence of the intrinsic conductance of a nanocontact on its shape by using the recursion-transfer-matrix method. Hour-glass, torus, and spherical shapes are defined through analytic potentials, the latter two serving as rough models for ring-like and spherical molecules, respectively. The sensitivity of the conductance to geometric details i
The FIRST-2MASS Red Quasar Survey II: An anomalously high fraction of LoBALs in searches for dust-reddened quasars
astro-phTanya Urrutia, Robert H. Becker, Richard L. White, Eilat Glikman
We present results on a survey to find extremely dust-reddened Type-1 Quasars. Combining the FIRST radio survey, the 2MASS Infrared Survey and the Sloan Digital Sky Survey, we have selected a candidate list of 122 potential red quasars. With more than 80% spectroscopically identified objects, well over 50% are classified as dust-reddened Type 1 quasars, whos
Luis J. Boya
We make an imaginative comparison between the Minimal Supersymmetric Standard Model and the 24-cell polytope in four dimensions, the Octacube.
Stefan Schmitt
The HERA ep collider and the experiments H1 and ZEUS operated from 1994-2007. A total integrated luminosity of almost 1 fb^-1 was collected at centre-of-mass energies up to 320 GeV. Results from searches for leptoquarks and squarks, final states with an isolated lepton and missing transverse momentum and final states with multi-leptons are presented. The lep
Shahar Even-Dar Mandel, Ron Lifshitz
Electrons in quasicrystals generically possess critical wave functions that are neither exponentially-localized nor extended, but rather decay algebraically in space. Nevertheless, motivated by recent calculations on the square and cubic Fibonacci quasicrystals, we investigate whether it is possible to obtain extended wave functions expressed as linear combi
I. Snyman, Yu. V. Nazarov
As a generic example of a voltage-driven superconducting structure we study a short superconductor connected to normal leads by means of low transparency tunnel junctions, with a voltage bias $V$ between the leads. The superconducting order parameter $Δ$ is to be determined self-consistently. We study the stationary states of the system as well as the dynami
Performance characteristics of positive and negative delayed feedback on chaotic dynamics of directly modulated InGaAsP semiconductor lasers
nlin.CDBindu M. Krishna, Manu. P. John, V. M. Nandakumaran
The chaotic dynamics of directly modulated semiconductor lasers with delayed optoelectronic feedback is studied numerically. The effects of positive and negative delayed optoelectronic feedback in producing chaotic outputs from such lasers with nonlinear gain reduction in its optimum value range is investigated using bifurcation diagrams. The results are con
Ioannis Karatzas, Ingrid-Mona Zamfirescu
We develop a martingale approach for studying continuous-time stochastic differential games of control and stopping, in a non-Markovian framework and with the control affecting only the drift term of the state-process. Under appropriate conditions, we show that the game has a value and construct a saddle pair of optimal control and stopping strategies. Cruci
Ravishankar Ramanathan, Dagomir Kaszlikowski, Marcin Wiesniak, Vlatko Vedral
We investigate the entanglement properties of resonating valence bond states on a two dimensional lattice in the presence of dopants that remove electrons from the lattice creating "holes". The movement of the holes generated by the Hubbard Hamiltonian in the regime of strong Coloumb repulsion in this setting could be responsible for the phenomenon o
Farhang Loran
For systems with a finite number of degrees of freedom, it is shown in [arXiv:hep-th/0303014] that first class constraints are Abelianizable if the Faddeev-Popov determinant is not vanishing for some choice of subsidiary constraints. Here, for irreducible first class constraint systems with SO(3) or SO(4) gauge symmetries, including a subset of coordinates i
Ulrich Menne
In this work the Isoperimetric Inequality for integral varifolds is used to obtain sharp estimates for the size of the set where the density quotient is small and to generalise Calderón's and Zygmund's theory of first order differentiability for functions in Lebesgue spaces from Lebesgue measure to integral varifolds.
Belle collaboration, H. O. Kim
We present results of a detailed study of the three-body $\bar{B}^0\toΣ_c(2455)^{0}\bar{p}π^{+}$ decay. A significant enhancement of signal events is observed in the $\bar{p}π^+$ mass system near $1.5 {\rm GeV}/c^2$ that is consistent with the presence of an intermediate baryonic resonance $\bar{N}^0$, where $\bar{N}^0$ is the $\bar{N}(1440)^0 P_{11}$ or $\b
Dapeng Zhan
We prove that the chordal SLE$_κ$ trace is reversible for $κ\in(0,4]$.
M. Fujiwara
We define a new finite type invariant for stably homeomorphic class of curves on compact oriented surfaces without boundaries and extend to a regular homotopy invariant for spherical curves.
Iver Brevik
Singularities in the dark energy late universe are discussed, under the assumption that the Lagrangian contains the Einstein term R plus a modified gravity term R^α, where αis a constant. The 4D fluid is taken to be viscous and composed of two components, one Einstein component where the bulk viscosity is proportional to the scalar expansion θ, and another m
Zdeněk Stuchlík, Sushan Konar, John C. Miller, Stanislav Hledík
We discuss the possibility that high-frequency QPOs in neutron-star binary systems may result from forced resonant oscillations of matter in the innermost parts of the accretion disc, excited by gravitational perturbations coming from asymmetries of the neutron star or from the companion star. We find that neutron-star asymmetries could, in principle, be eff
Hyun-Chul Kim, Youngman Kim
We investigate the quark-gluon mixed condensate based on an AdS/QCD model. Introducing a holographic field dual to the operator for the quark-gluon mixed condensate, we obtain the corresponding classical equation of motion. Taking the mixed condensate as an additional free parameter, we show that the present scheme reproduces very well experimental data. A f
W. Bietenholz, N. Cundy, M. Gockeler, R. Horsley
Lattice calculations could boost our understanding of Deep Inelastic Scattering by evaluating moments of the Nucleon Structure Functions. To this end we study the product of electromagnetic currents between quark states. The Operator Product Expansion (OPE) decomposes it into matrix elements of local operators (depending on the quark momenta) and Wilson coef
Michael Kuchiev, Victor Flambaum, Edward Shuryak
Froggatt, Nielsen et al suggested that the Higgs boson exchange between top quarks produces enough attraction to generate their multiple bound states. Furthermore they claimed that the system of 6 top and 6 anti-top quarks is bound so strongly that the binding energy nearly compensates the masses of t-quarks, making it very light. We calculated the energy of
Amarjit Budhiraja, Paul Dupuis, Vasileios Maroulas
The large deviations analysis of solutions to stochastic differential equations and related processes is often based on approximation. The construction and justification of the approximations can be onerous, especially in the case where the process state is infinite dimensional. In this paper we show how such approximations can be avoided for a variety of in
Alok C. Gupta, A. K. Srivastava, Paul J. Wiita
We present results of a periodicity search of 20 intra-day variable optical light curves of the blazar S5 0716+714, selected from a database of 102 light curves spanning over three years. We use a wavelet analysis technique along with a randomization test and find strong candidates for nearly periodic variations in eight light curves, with probabilities rang
Jian Zhou, Feng Yuan, Zuo-Tang Liang
Transverse polarization in the Hyperon production in the unpolarized deep inelastic scattering and pp collisions is studied in the twist-three approach, considering the contribution from the quark-gluon-antiquark correlation distribution in nucleon. We further compare our results for deep inelastic scattering to a transverse momentum dependent factorization
Misak M. Sargsian
We discus recent developments in theory of high energy two-body break-up of few-nucleon systems. The characteristics of these reactions are such that the hard two-body quasielastic subprocess can be clearly separated from the accompanying soft subprocesses. We discuss in details the hard rescattering model(HRM) in which hard photodisintegration develops in t
Jin Hu, Xiaoming Zhou, Gengkai Hu
We propose a general method to evaluate the material parameters for arbitrary shape transformation media. By solving the original coordinates in the transformed region via Laplace's equations, we can obtain the deformation field numerically, in turn the material properties of the devices to be designed such as cloaks, rotators or concentrators with arbit
Lara B. Anderson
In this thesis, we explore two approaches to string phenomenology. In the first half of the work, we investigate M-theory compactifications on spaces with co-dimension four, orbifold singularities. We construct M-theory on C^2/Z_N by coupling 11-dimensional supergravity to a seven-dimensional Yang-Mills theory located on the orbifold fixed-plane. The resulti
Toru Kawakubo, Katsuji Yamamoto
We present a quantum description of photon creation via dynamical Casimir effect based on the standard Hamiltonian formulation. The particle representation is constructed in the expansion of field operators fixed with the initial modes. The Hamiltonian is presented in terms of the creation and annihilation operators with the time-varying couplings which orig
The Modification of the Oppenheimer and Snyder Collapsing Dust Ball to a Static Ball in Discrete Space-time
gr-qcG. Chen
Besides the singularity problem, the famous Oppenheimer and Snyder solution is discovered to be of deficiency in two aspects: the internal Friedmann space-time does not have the inherent symmetry and cannot connect to the external Schwarzschild space-time. So the process of gravitational collapse described by this solution is doubtful. The deficiency, togeth
Victor H. Moll, Sinai Robins, K. Soodhalter
We study the action of Hecke operators on the set of hypergeometric functions. We show that the spectrum of these operators is the set of powers n^a and that polylogarithms play a dominant role in the study of the corresponding eigenfunctions. As a corollary, we obtain a characterization of completely multiplicative hypergeometric coefficients.
Evangelos Georgiadis, David Callan, Qing-Hu Hou
We count the number of walks of length n on a k-node circular digraph that cover all k nodes in two ways. The first way illustrates the transfer-matrix method. The second involves counting various classes of height-restricted lattice paths. We observe that the results also count so-called k-balanced strings of length n, generalizing a 1996 Putnam problem.