July 2009 arXiv papers — page 48

Gwynn J. Elfring, Eric Lauga

Some microorganisms, such as spermatozoa, synchronize their flagella when swimming in close proximity. Using a simplified model (two infinite, parallel, two-dimensional waving sheets), we show that phase-locking arises from hydrodynamics forces alone, and has its origin in the front-back asymmetry of the geometry of their flagellar waveform. The time-evoluti

P. Colin, D. Borla Tridon, E. Carmona, F. De Sabata

The MAGIC gamma-ray observatory has recently been upgraded by a second Cherenkov telescope at a distance of 85 m from the first one. Simultaneous observation of air showers with the two MAGIC telescopes (stereoscopic mode) will improve the reconstruction of the shower axis and solve the ambiguity in the impact point occurring in single-telescope mode. Also,

Franz Saija, Gianpietro Malescio, Santi Prestipino

We investigate the phase behaviour of a system of particles interacting through the exp-6 pair potential, a model interaction that is appropriate to describe effective interatomic forces under high compression. The soft-repulsive component of the potential is being varied so as to study the effect on reentrant melting and density anomaly. Upon increasing the

S. T. Bramwell, S. R. Giblin, S. Calder, R. Aldus

It has recently been predicted that certain magnetic materials contain mobile magnetic charges or `monopoles'. Here we address the question of whether these magnetic charges and their associated currents (`magnetricity') can be directly measured in experiment, without recourse to any material-specific theory. By mapping the problem onto Onsager's

Yasushi Komori, Kohji Matsumoto, Hirofumi Tsumura

We prove certain general forms of functional relations among Witten multiple zeta-functions in several variables (or zeta-functions of root systems). The structural background of those functional relations is given by the symmetry with respect to Weyl groups. From those relations we can deduce explicit expressions of values of Witten zeta-functions at positi

Tom Fennell, P. P. Deen, A. R. Wildes, K. Schmalzl

Spin ice materials are magnetic substances in which the spin directions map onto hydrogen positions in water ice. Recently this analogy has been elevated to an electromagnetic equivalence, indicating that the spin ice state is a Coulomb phase, with magnetic monopole excitations analogous to ice's mobile ionic defects. No Coulomb phase has yet been proved

A. Achilli, R. Godbole, A. Grau, G. Pancheri

We present the predictions of a model for proton-proton total cross-section at LHC. It takes into account both hard partonic processes and soft gluon emission effects to describe the proper high energy behavior and to respect the Froissart bound.

H. Bombin, M. Kargarian, M. A. Martin-Delgado

We introduce a two-body quantum Hamiltonian model with spins-$\half$ located on the vertices of a 2D spatial lattice. The model exhibits an exact topological degeneracy in all coupling regimes. This is a remarkable non-perturbative effect. The model has a $\Z_2\times \Z_2$ gauge group symmetry and string-net integrals of motion. There exists a gapped phase i

Yoneko Mochizuki, Hideo Yoshioka

We investigate transport properties of the junctions in which the graphene nanoribbon with the zigzag shaped edges consisting of the $N$ legs is sandwiched by the two normal metals by means of recursive Green's function method. The conductance and the transmission probabilities are found to have the remarkable properties depending on the parity of $N$. T

Naoto Tsuji, Takashi Oka, Hideo Aoki

We investigate a photoinduced insulator-metal transition in the Falicov-Kimball model with the dynamical mean-field theory (DMFT) extended to nonequilibrium systems in periodic modulations in time. When the photon energy of the pump light is $Ω\approx U$ ($U$: the interaction strength), a Drude-like peak is found to grow in the optical conductivity spectrum,

Charlier Emilie, Le Gonidec Marion, Rigo Michel

We show how to represent an interval of real numbers in an abstract numeration system built on a language that is not necessarily regular. As an application, we consider representations of real numbers using the Dyck language. We also show that our framework can be applied to the rational base numeration systems.

Rui Pedro Carreira, Jean-François Caron, Alberto Diaz Diaz

The mechanical problem discussed in this paper focuses on the stress state estimation in a composite laminate in the vicinity of a free edge or microcracks. To calculate these stresses, we use two models called Multiparticle Models of Multilayered Materials (M4). The first one can be considered as a stacking sequence of Reissner-Mindlin plates (5 kinematic f

Nadia Creignou, Herve Daude, Uwe Egly, Raphael Rossignol

The QSAT problem is the quantified version of the SAT problem. We show the existence of a threshold effect for the phase transition associated with the satisfiability of random quantified extended 2-CNF formulas. We consider boolean CNF formulas of the form $\forall X \exists Y φ(X,Y)$, where $X$ has $m$ variables, $Y$ has $n$ variables and each clause in $φ

Axel Hultman

Let $G$ be a connected reductive linear algebraic group over $\C$ with an involution $θ$. Denote by $K$ the subgroup of fixed points. In certain cases, the $K$-orbits in the flag variety $G/B$ are indexed by the twisted identities $\iot = \{θ(w^{-1})w\mid w\in W\}$ in the Weyl group $W$. Under this assumption, we establish a criterion for rational smoothness

Jens Jensen, Henrik Smith

The dimerized S=1/2 spins of the Cu ions in TlCuCl3 are ordered antiferromagnetically in the presence of a field larger than about 54 kOe in the zero-temperature limit. Within the mean-field approximation all thermal effects are frozen out below 6 K. Nevertheless, experiments show significant changes of the critical field and the magnetization below this tem

A. Shukla, R. Sahu, V. K. B. Kota

Half-lives $T_{1/2}^{2\nu}$ for two neutrino positron double beta decay modes $\beta^{+}$EC/ECEC are calculated for $^{74}$Se, a nucleus of current experimental interest, using deformed shell model based on Hartree-Fock states employing a modified Kuo interaction in ($^{2}p_{3/2}$, $^{1}f_{5/2}$, $^{2}p_{1/2}$, $^{1}g_{9/2}$) space. The calculated half-life

Mihai Letia, Nuno Preguiça, Marc Shapiro

A CRDT is a data type whose operations commute when they are concurrent. Replicas of a CRDT eventually converge without any complex concurrency control. As an existence proof, we exhibit a non-trivial CRDT: a shared edit buffer called Treedoc. We outline the design, implementation and performance of Treedoc. We discuss how the CRDT concept can be generalised

Emmanuel Breuillard, Ben Green

We describe the structure of "K-approximate subgroups'' of solvable subgroups of GL_n(C), showing that they have a large nilpotent piece. By combining this with the main result of our recent paper on approximate subgroups of torsion-free nilpotent groups, we show that such approximate subgroups are efficiently controlled by nilpotent progressions

Monica Pepe Altarelli

LHCb is a dedicated detector for b and c physics at the LHC. I will present a concise review of the detector design and expected performance together with some first results on the commissioning of the different sub-systems based on cosmic data and particle beams delivered by the LHC during the summer of 2008. The experiment is ready to exploit first data ex

P. Vesely, J. Kvasil, V. O. Nesterenko, W. Kleinig

The spin-flip M1 giant resonance is explored in the framework of Random Phase Approximation on the basis of the Skyrme energy functional. A representative set of eight Skyrme parameterizations (SkT6, SkM*, SLy6, SG2, SkO, SkO', SkI4, and SV-bas) is used. Light and heavy, spherical and deformed nuclei ($^{48}$Ca, $^{158}$Gd, $^{208}$Pb, and $^{238}$U) are

Patrick Brosnan, Zinovy Reichstein, Angelo Vistoli

We prove that the essential dimension of the spinor group Spin_n grows exponentially with n; in particular, we give a precise formula for this essential dimension when n is not divisible by 4. We use this result to show that the number of 3-fold Pfister forms needed to represent the Witt class of a general quadratic form of rank n with trivial discriminant a

A. B. Khanikaev, K. Yayoi, M. J. Steel, A. V. Baryshev

We study photonic band structure of two- and three-dimensional magnetophotonic crystals and the polarization properties of their eigenmodes using a plane wave expansion method. The alteration of the photonic band structure and eigenmodes by magnetization are examined. Two orientations are studied: in-plane magnetization and perpendicular magnetization. The m

Anna Hasenfratz

Monte Carlo Renormalization Group (MCRG) methods were designed to study the non-perturbative phase structure and critical behavior of statistical systems and quantum field theories. I adopt the 2-lattice matching method used extensively in the 1980's and show how it can be used to predict the existence of non-perturbative fixed points and their related c

Norihiko Minami

We compute the "moments" and its continuous anaougue of the random variable $\N^r \ni (k_1, k_2, ..., k_r) \mapsto \gcd(n,k_1k_2... k_r) \in \N$ by a purely elementary method. This generalizes a result of Kurokawa-Ochiai, which computed its "average" using some analysis involving L-function.

K. Sriram, Y. Ravi Kiron, P. Vivekananda Rao

The study of W UMa binary systems give a wealth of information about its nature as well as about its parent body (if any), like clusters. In this paper, we present the I passband photometric solutions of four W UMa binaries in the open cluster Berkeley 39 using the latest version of WD program. The result shows that, two binary systems are W subtype W UMa bi

Y. Brihaye, Th. Caebergs, T. Delsate

We consider the lagrangian of a self-interacting complex scalar field admitting generically Q-balls solutions. This model is extended by minimal coupling to electromagnetism and to gravity. A stationnary, axially-symmetric ansatz for the different fields is used in order to reduce the classical equations. The system of non-linear partial differential equatio

Shibei He, Xia Shen, Hui Wang, Wenlin Gong

Many significant results have been achieved in the fields of ghost imaging, in which the beam splitter is an indispensable optical component. This paper introduces a method to realize ghost imaging without beam splitter. And we study this method experimentally and theoretically. Finally, we suggest that our device can be applied to implement the ghost imagin

Yanou Cui, Tony Gherghetta, James D. Wells

We present a model of electroweak symmetry breaking in a warped extra dimension where electroweak symmetry is broken at the UV (or Planck) scale. An underlying conformal symmetry is broken at the IR (or TeV) scale generating masses for the electroweak gauge bosons without invoking a Higgs mechanism. By the AdS/CFT correspondence the W,Z bosons are identified

E. Akofor, A. P. Balachandran

In this paper, we initiate the study of finite temperature quantum field theories (QFT's) on the Moyal plane. Such theories violate causality which influences the properties of these theories. In particular, causality influences the fluctuation-dissipation theorem: as we show, a disturbance in a space-time region $M_1$ creates a response in a space-time

Nobuyasu Shiga, Ying Li, Hiroyuki Ito, Shigeo Nagano

Precision saturation spectroscopy of the $^{88}{\rm Sr} ^1S_0-^3P_1$ is performed in a vapor cell filled with various rare gas including He, Ne, Ar, and Xe. By continuously calibrating the absolute frequency of the probe laser, buffer gas induced collision shifts of $\sim $kHz are detected with gas pressure of 1-20 mTorr. Helium gave the largest fractional s

Marcos M. Alexandrino

Consider a singular Riemannian foliation (s.r.f for short) on a compact manifold. By successive blow-ups along the strata, we construct a regular Riemannian foliation on another compact Riemannian manifold and a desingularization map that projects leaves of the regular Riemannian foliation into leaves of the s.r.f. This result generalizes a previous result d

D. J. Miller

Simple physical models of a measuring rod and of a clock are used to demonstrate the contraction of objects and clock retardation in special relativity. It is argued that the models could help in promoting student understanding of special relativity and in distinguishing between dynamical and purely perspectival effects.

E. A. Leicht, Raissa M. D'Souza

Most networks of interest do not live in isolation. Instead they form components of larger systems in which multiple networks with distinct topologies coexist and where elements distributed amongst different networks may interact directly. Here we develop a mathematical framework based on generating functions for analyzing a system of L interacting networks

Nathan K. Johnson-McDaniel, Nicolas Yunes, Wolfgang Tichy, Benjamin J. Owen

(Abridged) By asymptotically matching a post-Newtonian (PN) metric to two tidally perturbed Schwarzschild metrics, we generate approximate initial data (in the form of a 4-metric) for a nonspinning black hole binary in a circular orbit. We carry out this matching through O(v^4) in the binary's orbital velocity v, so the resulting data are conformally curved.

R. S. Raghavan

The role of quantum mechanical time-energy uncertainty (TEU) is central in resonant neutrino (nue) reactions (3H to 3He to 3H) because of the unusual 18 y lifetime of 3H. The TEU explicitly manifests itself by a non-intuitive but quantitatively predictable spontaneous temporal growth of the nue resonance signal. A slower growth rate signifies violation of TE

Vladimir Lipunov, Victor Kornilov, Evgeny Gorbovskoy, Nikolaj Shatskij

The main goal of the MASTER-Net project is to produce a unique fast sky survey with all sky observed over a single night down to a limiting magnitude of 19 - 20mag. Such a survey will make it possible to address a number of fundamental problems: search for dark energy via the discovery and photometry of supernovas (including SNIa), search for exoplanets, mic

H. Tian, L. -D. Xia

We investigate intensity oscillations observed simultaneously in the quiet chromosphere and in the corona, above an enhanced network area at the boundary of an equatorial coronal hole. A Fourier analysis is applied to a sequence of images observed in the 171 A and 1600 A passbands of TRACE. Four interesting features above the magnetic network are further inv

The CDF Collaboration, Aaltonen T. et al

We report on a search for the standard-model Higgs boson in $p\bar{p}$ collisions at $\sqrt{s}=1.96$ TeV using an integrated luminosity of 2.0/fb. We look for production of the Higgs boson decaying to a pair of bottom quarks in association with a vector boson $V$ ($W$ or $Z$) decaying to quarks, resulting in a four-jet final state. Two of the jets are requir

Fedor Herbut

After introducing sketchily Bohr's wave-particle complementarity principle in his own words, a derivation of an extended form of the principle from standard quantum mechanics is performed. Reality-evaluation of each step is given. The derived theory is applied to simple examples and the extended entities are illustrated in a thought experiment. Assessmen

M. J. Madsen, D. R. Brown, S. R. Krutz, M. J. Milliman

We present an update of the "refractive index of air" experiment commonly used in optics and undergraduate advanced labs. The refractive index of air is based on the average molecular polarizability, which we measured from the period of the phase shift in a Michelson interferometer as a function of pressure. Our value of the average molecular polariz

Diana Savin

In this paper, we prove a theorem about the integer solutions to the Diophantine equation $x^{4}-q^{4}=py^{r}$, extending previous work of K.Gy\H ory, and F.Luca and A.Togbe, and of the author.

Veerle Ledoux, Simon J. A. Malham, Vera Thummler

We present a new numerical method for computing the pure-point spectrum associated with the linear stability of coherent structures. In the context of the Evans function shooting and matching approach, all the relevant information is carried by the flow projected onto the underlying Grassmann manifold. We show how to numerically construct this projected flow

Naoki Masuda, Yoji Kawamura, Hiroshi Kori

Many complex networks are described by directed links; in such networks, a link represents, for example, the control of one node over the other node or unidirectional information flows. Some centrality measures are used to determine the relative importance of nodes specifically in directed networks. We analyze such a centrality measure called the influence.

Naoki Masuda, Yoji Kawamura, Hiroshi Kori

Many systems, ranging from biological and engineering systems to social systems, can be modeled as directed networks, with links representing directed interaction between two nodes. To assess the importance of a node in a directed network, various centrality measures based on different criteria have been proposed. However, calculating the centrality of a nod

Tatyana S. Turova

Consider the random graph on $n$ vertices $1, ..., n$. Each vertex $i$ is assigned a type $X_i$ with $X_1, ..., X_n$ being independent identically distributed as a nonnegative discrete random variable $X$. We assume that ${\bf E} X^3<\infty$. Given types of all vertices, an edge exists between vertices $i$ and $j$ independent of anything else and with probab

D. Cohen, G. Denham, M. Falk, A. Varchenko

If F is a master function corresponding to a hyperplane arrangement A and a collection of weights y, we investigate the relationship between the critical set of F, the variety defined by the vanishing of the one-form w = d log F, and the resonance of y. For arrangements satisfying certain conditions, we show that if y is resonant in dimension p, then the cri

S. Raychaudhury, S. Giacintucci, E. O&#39;Sullivan, J. M. Vrtilek

The lack of very cool gas at the cores of groups and clusters of galaxies, even where the cooling time is significantly shorter than the Hubble time, has been interpreted as evidence of sources that re-heat the intergalactic medium. Most studies of rich clusters adopt AGN feedback to be this source of heating. From ongoing GMRT projects involving clusters an

Javiera Guedes, Piero Madau, Micheal Kuhlen, Jürg Diemand

The coalescence of a massive black hole (MBH) binary leads to the gravitational-wave recoil of the system and its ejection from the galaxy core. We have carried out N-body simulations of the motion of a MBH = 3.7x10^6 Msun MBH remnant in the Via Lactea I simulation, a Milky Way sized dark matter halo. The black hole receives a recoil velocity of Vkick = 80,

Alice Bernamonti, Ben Craps

It is known that certain AdS boundary conditions allow smooth initial data to evolve into a big crunch. To study this type of cosmological singularity, one can use the dual quantum field theory, where the non-standard boundary conditions are reflected by the presence of a multi-trace potential unbounded below. For specific AdS_4 and AdS_5 models, we provide

Marco Cirelli, Fabio Iocco, Paolo Panci

Dark Matter annihilations after recombination and during the epoch of structure formation deposit energy in the primordial intergalactic medium, producing reionization and heating. We investigate the constraints that are imposed by the observed optical depth of the Universe and the measured temperature of the intergalactic gas. We find that the bounds are si

M. Lopez, N. Otte, M. Rissi, T. Schweizer

The MAGIC telescope has detected for the first time pulsed gamma-rays from the Crab pulsar in the VHE domain. The observations were performed with a newly developed trigger system that allows us to lower the energy threshold of the telescope from 55 GeV to 25 GeV. We present a comparison of light curves measured by our experiment with the one measured by spa

I. Paul, M. Civelli

We study the finite-frequency inter-band transition peak in the optical conductivity of a heavy fermion system close to a Kondo breakdown quantum critical point, where the lattice Kondo temperature vanishes. As the system approaches the phase transition from the heavy Fermi liquid side, we find a new cross-over regime where the peak position is related to, b

Nir Ailon, Bernard Chazelle, Kenneth L. Clarkson, Ding Liu

We investigate ways in which an algorithm can improve its expected performance by fine-tuning itself automatically with respect to an unknown input distribution D. We assume here that D is of product type. More precisely, suppose that we need to process a sequence I_1, I_2, ... of inputs I = (x_1, x_2, ..., x_n) of some fixed length n, where each x_i is draw

Vladimir Shevelev

For every $a\geq1$ we give a recursion algorithm of building of set of solutions of equations of the form $t(x+a)=t(x)$ and $t(x+a)=1-t(x),$ where $\{t(n)\}$ is Thue-Morse sequence. We pose an open problem and two conjectures.

S. L. Bloom, Z. Esik

An algebraic tree T is one determined by a finite system of fixed point equations. The frontier \Fr(T) of an algebraic tree t is linearly ordered by the lexicographic order \lex. When (\Fr(T),\lex) is well-ordered, its order type is an \textbf{algebraic ordinal}. We prove that the algebraic ordinals are exactly the ordinals less than $\omega^{\omega^\omega}$

Andrei M. Beloborodov

Nuclear and Coulomb collisions in GRB jets create a hot electron-positron plasma. This collisional heating starts when the jet is still opaque and extends to the transparent region. The e+- plasma radiates its energy. As a result, a large fraction of the jet energy is converted to escaping radiation with a well-defined spectrum. The process is simulated in d

Manwai Yuen

In this paper, we use integration method to show that there is no existence of global $C^{2}$ solution with compact support, to the pressureless Euler-Poisson equations with attractive forces in $R^{N}$. And the similar result can be shown, provided that the uniformly bounded functional:% \int_{Ω(t)}Kγ(γ-1)ρ^{γ-2}(\nablaρ)^{2}% dx+\int_{Ω(t)}Kγρ^{γ-1}Δρdx+ε\

R. Orito, E. Bernardini, D. Bose, A. Dettlaff

MAGIC-II is the second imaging atmospheric Cherenkov telescope of the MAGIC observatory, which has recently been inaugurated on Canary island of La Palma. We are currently developing a new camera based on clusters of hybrid photon detectors (HPD) for the upgrade of MAGIC-II. The photon detectors feature a GaAsP photocathode and an avalanche diode as electron

Piotr Garbaczewski

We analyze confining mechanisms for L\'evy flights evolving under an influence of external potentials. Given a stationary probability density function (pdf), we address the reverse engineering problem: design a jump-type stochastic process whose target pdf (eventually asymptotic) equals the preselected one. To this end, dynamically distinct jump-type process

Anthony Chefles

A quantum analogue of the famous Blackwell Theorem in classical statistics has recently been proposed. Given two quantum channels A and B, a set of payoff functions have been proven to have values for B at least as high as they are for A if and only if there exists a quantum garbling channel E such that A=EB. When such a channel E exists, we can globally com

E. Kozik, K. Van Houcke, E. Gull, L. Pollet

We show that Monte Carlo sampling of the Feynman diagrammatic series (DiagMC) can be used for tackling hard fermionic quantum many-body problems in the thermodynamic limit by presenting accurate results for the repulsive Hubbard model in the correlated Fermi liquid regime. Sampling Feynman&#39;s diagrammatic series for the single-particle self-energy we can

J. Sadeghi, H. Farahani, B. Pourhassan

In this paper, we investigate thermal equilibrium in string gas cosmology which is dominated by closed string.We consider two interesting regimes, Hagedorn and radiation regimes.We find that for short strings in small radius of Hagedorn regime very large amount of energy requested to have thermal equilibrium but for long strings in such system a few energy i

Shih Hao Lan, Albert K. H. Kong, Frank Verbunt, Walter H. G. Lewin

We report on the Chandra X-ray Observatory and Hubble Space Telescope observation of two low core density globular clusters, NGC6144 and E3. By comparing the number of X-ray sources inside the half-mass radius to those outside, we found 6 X-ray sources within the half-mass radius of NGC6144, among which 4 are expected to be background sources; 3 X-ray source

Yungui Gong, Tianjun Li

We propose a modified holographic dark energy (MHDE) model with the Hubble scale as the infrared (IR) cutoff. Introducing the infinite extra dimension(s) at very large distance scale, we consider the black hole mass in higher dimensions as the ultraviolet cutoff. Thus, we can probe the effects of the IR infinite extra dimension(s). As a concrete example, we

P. V. Dong, L. T. Hue, H. T. Hung, H. N. Long

The symmetry factor of Feynman diagrams for real and complex scalar fields is presented. Being analysis of Wick expansion for Green functions, the mentioned factor is derived in a general form. The symmetry factor can be separated into two ones corresponding to that of connected and vacuum diagrams. The determination of symmetry factors for the vacuum diagra

Vladimir V. Kisil

We argue with claims of the paper [Agostini F., Caprara S. and Ciccotti G., Europhys. Lett. EPL, 78 (2007) Art. 30001, 6] that the quantum-classic bracket introduced in [arXiv:quant-ph/0506122] produces &#34;artificial coupling&#34; and has &#34;genuinely classical nature&#34;. Keywords: p-mechanics, quantum, classic, commutator, Poisson bracket, mixing, cou

Hefeng Wang, Sabre Kais, Alán Aspuru-Guzik, Mark R. Hoffmann

Simulating a quantum system is more efficient on a quantum computer than on a classical computer. The time required for solving the Schr\"odinger equation to obtain molecular energies has been demonstrated to scale polynomially with system size on a quantum computer, in contrast to the well-known result of exponential scaling on a classical computer. In this

Fuyuhiko Tanaka

Excluding the concept of probability in quantum mechanics, we derive Born&#39;s law from the remaining postulates in quantum mechanics using type method. We also give a way of determining the unknown parameter in a state vector based on an indirect measurement model. While Deutsch adopt a concept of rational decision-maker who introduces probability, we adop

Seoktae Koh

We calculate the spectrum of the relic gravitational wave due to the trans-Planckian effect in which the standard linear dispersion relations may be modified. Of the modified dispersion relations suggested in literatures which have investigated the trans-Planckian effect, we especially use the Corley-Jacobson dispersion relations. The Corley-Jacobson type mo

S. Takayoshi, Hiroshi Fukuyama

We described details of a method to estimate with good accuracy the mosaic angle distributions of microcrystallites (platelets) in exfoliated graphite like Grafoil which is commonly used as an adsorption substrate for helium thin films. The method is based on analysis of resonance field shifts in continuous-wave (CW) NMR spectra of $^{3}$He ferromagnetic mon

P. Castelo Ferreira

It is suggested a metric ansatz to describe local matter in an expanding universe, hence interpolating between the Schwarzschild metric at small spatial scales and the FLRW metric at large spatial scales. This is acomplished maintaining space-time free of singularities except for the Schwarzschild mass pole at the origin as opposed to metrics already conside

Rudranil Basu, Romesh K. Kaul, Parthasarathi Majumdar

The decade-old formulation of the isolated horizon classically and within loop quantum gravity, and the extraction of the microcanonical entropy of such a horizon from this formulation, is reviewed, in view of recent renewed interest. There are two main approaches to this problem: one employs an SU(2) Chern-Simons theory describing the isolated horizon degre

Feng-Wen An

Assume that $X$ and $Y$ are arithmetic schemes, i.e., integral schemes of finite types over $Spec(\mathbb{Z})$. Then $X$ is said to be quasi-galois closed over $Y$ if $X$ has a unique conjugate over $Y$ in some certain algebraically closed field, where the conjugate of $X$ over $Y$ is defined in an evident manner. Now suppose that $ϕ:X\to Y$ is a surjective

Robert Wagner

The total set of the 14 active galactic nuclei detected by MAGIC so far includes well-studied bright blazars like Mkn 501, the giant radio galaxy M 87, but also the distant flat-spectrum radio quasar 3C 279, and an intriguing gamma-ray source in the 3C 66A/B region, whose energy spectrum is not compatible with the expectations from 3C 66A. Besides scheduled

Giacomo Bonnoli, Ching-Cheng Hsu, Florian Goebel, Elina Lindfors

The HBL-type blazar Markarian 421 is one of the brightest TeV gamma-ray sources of the Northern sky. From December 2007 until June 2008 it was intensively observed in the VHE (E>100 GeV) band by the MAGIC gamma-ray telescope. The source showed intense and prolonged activity during the whole period. In some nights the integral flux rose up to 3.6 Crab units (

Ronald Benjamin

The energetics of a Brownian heat engine and heat pump driven by position dependent temperature, known as the Büttiker-Landauer heat engine and heat pump, is investigated by numerical simulations of the inertial Langevin equation. We identify parameter values for optimal performance of the heat engine and heat pump. Our results qualitatively differ from appr

A. Nihat Berker, Michael Hinczewski, Roland R. Netz

Percolation in a scale-free hierarchical network is solved exactly by renormalization-group theory, in terms of the different probabilities of short-range and long-range bonds. A phase of critical percolation, with algebraic (Berezinskii-Kosterlitz-Thouless) geometric order, occurs in the phase diagram, in addition to the ordinary (compact) percolating phase

Paul R. Anderson, Carmen Molina-Paris, Emil Mottola

Linearized fluctuations of quantized matter fields and the spacetime geometry around de Sitter space are considered in the case that the matter fields are conformally invariant. Taking the unperturbed state of the matter to be the de Sitter invariant Bunch-Davies state, the linear variation of the stress tensor about its self-consistent mean value serves as

J. Manuel Garcia-Islas

We show that counting different configurations that give rise to black hole entropy in loop quantum gravity is related to partitions in number theory.

Sergiy Koshkin

We study geometric variational problems for a class of nonlinear sigma-models in quantum field theory. Mathematically, one needs to minimize an energy functional on homotopy classes of maps from closed 3-manifolds into compact homogeneous spaces G/H. The minimizers are known as Hopfions and exhibit localized knot-like structure. Our main results include prov

Carlos Escudero

This is an addendum to the Reply Comment [Phys. Rev. Lett. 102, 139602 (2009), arXiv:0811.0518] to Comment [Phys. Rev. Lett. 102, 139601 (2009), arXiv:0810.4791] on Letter [Phys. Rev. Lett. 100, 116101 (2008), arXiv:0804.1898].

C. C. Hsu, K. Satalecka, M. Thom, M. Backes

Blazars, a class of Active Galactic Nuclei (AGN) characterized by a close orientation of their relativistic outflows (jets) towards the line of sight, are a well established extragalactic TeV $γ$-ray emitters. Since 2006, three nearby and TeV bright blazars, Markarian (Mrk) 421, Mrk 501 and 1ES 1959+650, are regularly observed by the MAGIC telescope with sin

M. K. Tavassoly

A formalism for the construction of some classes of Gazeau$-$Klauder squeezed states, corresponding to arbitrary solvable quantum systems with a known discrete spectrum, are introduced. As some physical applications, the proposed structure is applied to a few known quantum systems and then statistical properties as well as squeezing of the obtained squeezed

A. Fang, Th. Koschny, M. Wegener, C. M. Soukoulis

We present a computational scheme allowing for a self-consistent treatment of a dispersive metallic photonic metamaterial coupled to a gain material incorporated into the nanostructure. The gain is described by a generic four-level system. A critical pumping rate exists for compensating the loss of the metamaterial. Nonlinearities arise due to gain depletion

L. Parnovski, A. V. Sobolev

We consider a periodic self-adjoint pseudo-differential operator $H=(-Δ)^m+B$, $m>0$, in $\R^d$ which satisfies the following conditions: (i) the symbol of $B$ is smooth in $\bx$, and (ii) the perturbation $B$ has order less than $2m$. Under these assumptions, we prove that the spectrum of $H$ contains a half-line. This, in particular implies the Bethe-Somme

Gabriela Litcanu, Cristian Morales-Rodrigo

In this paper we analyze a mathematical model focusing on key events of the cells invasion process. Global well-possedness and asymptotic behaviour of nonnegative solutions to the corresponding coupled system of three nonlinear partial differential equations are studied.

Jens Erler

I review constraints on the Standard Model (SM) Higgs boson from high energy electroweak (EW) precision data. The same data set also strongly limits various mixing effects of hypothetical extra neutral gauge bosons (Z&#39;) with the ordinary Z. I also discuss low energy precision measurements which are sensitive to other aspects of Z&#39; physics, such as th

S. Hubrig, M. Schoeller, I. Savanov, R. V. Yudin

We report the results of our search for magnetic fields in a sample of 16 field Be stars, the binary emission-line B-type star upsilon Sgr, and in a sample of fourteen members of the open young cluster NGC3766 in the Carina spiral arm. The sample of cluster members includes Be stars, normal B-type stars and He-strong/He-weak stars. Nine Be stars have been st

M. A. Rajabpour, S. M. Vaez Allaei

Equilibrium and non-equilibrium growth phenomena, e.g., surface growth, generically yields self-affine distributions. Analysis of statistical properties of these distributions appears essential in understanding statistical mechanics of underlying phenomena. Here, we analyze scaling properties of the cumulative distribution of iso-height loops (i.e., contour

B. Mirzaii

In this paper the third homology group of the linear group GL_2(R) with integral coefficients is investigated, where R is a commutative ring with many units.

Santabrata Das, Peter A. Becker, Truong Le

We develop and discuss global accretion solutions for viscous ADAF disks containing centrifugally supported isothermal shock waves. The fact that such shocks can exist at all in ADAF disks is a new result. Interestingly, we find that isothermal shocks can form even when the level of viscous dissipation is relatively high. In order to better understand this p

Eric Poisson

The tidal interaction of a (rotating or nonrotating) black hole with nearby bodies produces changes in its mass, angular momentum, and surface area. Similarly, tidal forces acting on a Newtonian, viscous body do work on the body, change its angular momentum, and part of the transferred gravitational energy is dissipated into heat. The equations that describe

Manwai Yuen

We study the stabilities and classical solutions of Euler-Poisson equations of describing the evolution of the gaseous star in astrophysics. In fact, we extend the study the stabilities of Euler-Poisson equations with or without frictional damping term to some special dimensional spaces. Besides, by using the second inertia function in 2 dimension of Euler-P

Peter A. Becker, Santabrata Das, Truong Le

In this Letter, we present a new self-consistent theory for the production of the relativistic outflows observed from radio-loud black hole candidates and active galaxies as a result of particle acceleration in hot, viscous accretion disks containing standing, centrifugally-supported isothermal shocks. This is the first work to obtain the structure of such d

Peter A. Becker

The partial differential equation governing the formation of the radiation spectrum in the shocked plasma accreting onto an x-ray pulsar is solved to obtain the associated Green&#39;s function describing the scattering of monochromatic radiation injected into the plasma at a fixed altitude above the star. Collisions between the photons and the infalling elec

Geoffrey Lovelace, Yanbei Chen, Michael Cohen, Jeffrey D. Kaplan

Research on extracting science from binary-black-hole (BBH) simulations has often adopted a &#34;scattering matrix&#34; perspective: given the binary&#39;s initial parameters, what are the final hole&#39;s parameters and the emitted gravitational waveform? In contrast, we are using BBH simulations to explore the nonlinear dynamics of curved spacetime. Focusi

M. F. Gelin, D. S. Kosov

We have derived several relations, which allow the evaluation of the system free energy changes in the leading order in $\hbar^{2}$ along classically generated trajectories. The results are formulated in terms of purely classical Hamiltonians and trajectories, so that semiclassical partition functions can be computed, e.g., via classical molecular dynamics s

A. Eggenberger, S. Udry, G. Chauvin, J. -L. Beuzit

The presence of a stellar companion closer than ~100 AU is likely to affect planet formation and evolution. Yet, the precise effects and their actual impact on planet occurrence are still debated. To bring observational constraints, we have conducted with VLT/NACO a systematic adaptive optics survey for close stellar companions to 130 solar-type stars with a

Ganquan Xie, Jianhua Li, Feng Xie, Lee Xie

In this paper, we propose a novel electromagnetic (EM) cloaking structure that consists of two annular layers between three spherical shells and model its performance numerically and theoretically by using a Global and Local EM field (GL) method. The two annular layers contain distinct cloaking materials: the outer layer provides invisibility; the inner laye

Emmanuel Amiot

The problem of phase retrieval is a difficult one which remains far from solved. Two homometric sets are always connected by way of a convolution product by some spectral unit, though not necessarily in a unique way. Here we elucidate one small aspect, the subgroup of spectral units with finite order. Its elements are completely characterized by relations be