January 2007 arXiv papers — page 10

V. Desai, J. J. Dalcanton, A. Aragon-Salamanca, P. Jablonka

We describe Hubble Space Telescope (HST) imaging of 10 of the 20 ESO Distant Cluster Survey (EDisCS) fields. Each ~40 square arcminute field was imaged in the F814W filter with the Advanced Camera for Surveys Wide Field Camera. Based on these data, we present visual morphological classifications for the ~920 sources per field that are brighter than I_auto=23

P. J. McCarthy, H. Yan, R. G. Abraham, E. Mentuch

We describe a compact cluster of massive red galaxies at z=1.51 discovered in one of the Gemini Deep Deep Survey (GDDS) fields. Deep imaging with the Near Infrared Camera and Multi Object Spectrometer (NICMOS) on the Hubble Space Telescope reveals a high density of galaxies with red optical to near-IR colors surrounding a galaxy with a spectroscopic redshift

B. De Pontieu, V. H. Hansteen, L. Rouppe van der Voort, M. van Noort

We present unprecedented high resolution H-alpha observations, obtained with the Swedish 1-m Solar Telescope, that, for the first time, spatially and temporally resolve dynamic fibrils in active regions on the Sun. These jet-like features are similar to mottles or spicules in quiet Sun. We find that most of these fibrils follow almost perfect parabolic paths

M. S. Cunha

I review recent theoretical work on rapidly oscillating Ap stars and discuss key aspects of the physics of the oscillations observed in this class of pulsators.

Scott C. Noble, Po Kin Leung, Charles F. Gammie, Laura G. Book

The radio source Sagittarius A* (Sgr A*) is believed to be a hot, inhomogeneous, magnetized plasma flowing near the event horizon of the 3 million solar mass black hole at the galactic center. At a distance of 8000 parsecs the black hole would be among the largest black holes as judged by angular size. Recent observations are consistent with the idea that th

N. R. Tanvir, P. Jakobsson

The extreme luminosity of gamma-ray bursts (GRBs) and their afterglows means they are detectable, in principle, to very high redshifts. Although the redshift distribution of GRBs is difficult to determine, due to incompleteness of present samples, we argue that for Swift-detected bursts the median redshift is between 2.5 and 3, with a few percent likely at z

E. Orru', M. Murgia, L. Feretti, F. Govoni

Spectral index images can be used to constraint the energy spectrum of relativistic electrons and magnetic field distribution in radio halos and relics, providing useful information to understand their formation, evolution and connection to cluster merger processes. We present low-frequency images of the two clusters of galaxies: A2744 and A2219, in which a

D. R. Ballantyne, C. Papovich

We present the results of calculations of the cosmic AGN background spectrum from 3 keV (4\times 10^{-4} microns) to 1000 microns. These computations make use of the measured X-ray luminosity function and its evolution, as well as fits from synthesis models of the cosmic X-ray background (CXB) to predict the AGN contribution to the cosmic infrared background

I. Sableviciute, V. Vansevicius, K. Kodaira, D. Narbutis

We present structural parameters for 51 compact star clusters from the survey of star clusters conducted in the South-West field of the M31 disk by Kodaira et al. (2004). Structural parameters of the clusters were derived by fitting the 2-D King and EFF (Elson, Fall and Freeman 1987) models to the V-band cluster images. Structural parameters derived for two

Marco Chiaberge

We have studied the nuclear emission detected in high-resolution radio and optical data of carefully selected samples of low luminosity AGN (LLAGN) in the local universe. When the Eddington ratio is plotted against the nuclear ``radio-loudness'' parameter, sources divide according to their physical properties. It is thus possible to disentangle betwe

J. M. Weisberg, S. Stanimirovic

We describe the use of pulsars to study small-scale neutral structure in the interstellar medium (ISM). Because pulsars are high velocity objects, the pulsar-Earth line of sight sweeps rapidly across the ISM. Multiepoch measurements of pulsar interstellar spectral line spectra therefore probe ISM structures on AU scales. We review pulsar measurements of smal

J. Lazio, R. J. Macdowall, J. Burns, L. Demaio

Observations at radio wavelengths address key problems in astrophysics, astrobiology, and lunar structure including the first light in the Universe (the Epoch of Reionization), the presence of magnetic fields around extrasolar planets, particle acceleration mechanisms, and the structure of the lunar ionosphere. Moreover, achieving the performance needed to a

Philip Massey, Emily M. Levesque, K. A. G. Olsen, bertrand Plez

We call attention to the fact that one of the brightest red supergiants in the SMC has recently changed its spectral type from K0-1 I (December 2004) to M4 I (December 2005) and back to K0-1 I (September 2006). An archival spectrum from the Very Large Telescope reveals that the star was even cooler (M4.5-M5 I) in December 2001. By contrast, the star was obse

HESS Collaboration, F. A. Aharonian

A recently proposed novel technique for the detection of cosmic rays with arrays of Imaging Atmospheric Cherenkov Telescopes is applied to data from the High Energy Stereoscopic System (H.E.S.S.). The method relies on the ground based detection of Cherenkov light emitted from the primary particle prior to its first interaction in the atmosphere. The charge o

C. Argiroffi, A. Maggio, G. Peres

We study the properties of X-ray emitting plasma of MP Mus, an old classical T Tauri star. We aim at checking whether an accretion process produces the observed X-ray emission and at deriving the accretion parameters and the characteristics of the shock-heated plasma. We compare the properties of MP Mus with those of younger classical T Tauri stars to test w

C. M. Copperwheat, M. Cropper, R. Soria, K. Wu

We have constructed a model which describes the optical emission from ultraluminous X-ray sources (ULXs), and have used it to constrain the parameters of seven ULX systems. Our model assumes a binary nature for ULXs, and accounts for optical emission from an X-ray irradiated companion star and accretion disk. We apply our model to six different ULX optical c

K. Lehtinen, M. Juvela, K. Mattila, D. Lemke

Our aim is to compare the infrared properties of big, ``classical'' dust grains with visual extinction in the cloud L1642. In particular, we study the differences of grain emissivity between diffuse and dense regions in the cloud. The far-infrared properties of dust are based on large-scale 100um and 200um maps. Extinction through the cloud has been

Stephanie Courty, Gunnlaugur Bjornsson, Einar H. Gudmundsson

We explore galaxy properties in general and properties of host galaxies of gamma-ray bursts (GRBs) in particular, using N-body/Eulerian hydrodynamic simulations and the stellar population synthesis model, Starburst99, to infer observable properties. We identify simulated galaxies that have optical star formation rate (SFR) and SFR-to-luminosity ratio similar

G. Sorrentino, A. Rifatto

We investigate the environmental dependence of galaxies with the star formation rate (SFR) in a complete volume limited sample of 91566 galaxies, in the redshift range $0.05 \le z \le 0.095$, and with $M_r=-20.0$ (that is M$^*$ + 1.45), selected from the Sloan Digital Sky Survey Data Release 4 (SDSS-DR4). The environment is characterized by the local number

Giovanni Carraro, Raul de la Fuente Marcos, Sandro Villanova, Christian Moni Bidin

Observations indicate that present-day star formation in the Milky Way disk takes place in stellar ensembles or clusters rather than in isolation. Bound, long lived stellar groups are known as open clusters. They gradually lose stars and in their final evolutionary stages they are severely disrupted leaving an open cluster remnant made of a few stars. In thi

M. Martín Manjón, M. Mollá, A. I. Díaz

We have studied the viability of new theoretical models which combine a chemical evolution code, an evolutionary synthesis code and a photoionization code, to understand the star formation and evolution of H{\sc ii} galaxies. The emission lines observed in H{\sc ii} galaxies are reproduced by meas of the photoionization code CLOUDY, using as ionizing spectru

Mercedes Mollá

We show autoconsistent chemical and spectro-photometric evolution models applied to spiral and irregular galaxies. Evolutionary synthesis models usually used to explain the stellar component spectro-photometric data, are combined with chemical evolution models, to determine precisely the evolutionary history of spiral and irregular galaxies. In this piece of

Woong-Tae Kim, Eve C. Ostriker

Galactic disks consist of both stars and gas. The gas is more dynamically responsive than the stars, and strongly nonlinear structures and velocities can develop in the ISM even while stellar surface density perturbations remain fractionally small. We use 2D numerical simulations to explore formation of bound clouds and turbulence generation in the gas of tw

Sheila J. Kannappan, Eric Gawiser

We show that different stellar-mass estimation methods yield overall mass scales that disagree by factors up to ~2 for the z=0 galaxy population, and more importantly, relative mass scales that sometimes disagree by factors >~3 between distinct classes of galaxies (spiral/irregular types, classical E/S0s, and E/S0s whose colors reflect recent star formation)

Rishi Khatri, Benjamin D. Wandelt

We investigate the effect of variation in the value of the fine structure constant at high redshifts (recombination > z > 30) on the absorption of the cosmic microwave background (CMB) at 21 cm hyperfine transition of the neutral atomic hydrogen. We find that the 21 cm signal is very sensitive to the variations in the fine structure constant and it is so far

John F. Beacom, Matthew D. Kistler

Recent Milagro observations of the Cygnus region have revealed both diffuse TeV gamma-ray emission and a bright and extended TeV source, MGRO J2019+37, which seems to lack an obvious counterpart at other wavelengths. Additional study of this curious object also promises to provide important clues concerning one of the Milky Way's most active environments

Suchetana Chatterjee, Arthur Kosowsky

The observed relationship between X-ray luminosity and temperature of the diffuse intercluster medium clearly shows the effect of nongravitational heating on the formation of galaxy clusters. Quasar feedback into the intergalactic medium can potentially be an important source of heating, and can have significant impact on structure formation. This feedback p

Aidan Burch

We consider two technical developments of the formalism of continuous-time histories. First, we provide an explicit description of histories of the simple harmonic oscillator on the classical histories phase space, comparing and contrasting the Q, P and Wigner representations; we conclude that a representation based on coherent states is the most appropriate

Toufik Mansour, Matthias Schork

In this article combinatorial aspects of normal ordering annihilation and creation operators of a multi-mode boson system are discussed. The modes are assumed to be coupled since otherwise the problem of normal ordering is reduced to the corresponding problem of the single-mode case. To describe the normal ordering in the multi-mode case for each mode a colo

Ehud Nakar

Two types of Gamma-ray bursts (GRBs) are observed: short duration hard spectrum GRBs and long duration soft spectrum GRBs. For many years long GRBs were the focus of intense research while the lack of observational data limited the study of short-hard GRBs (SHBs). In 2005 a breakthrough occurred following the first detections of SHB afterglows, longer wavele

Eric B. Ford, Eugene Chiang

As many as 5 ice giants--Neptune-mass planets composed of 90% ice and rock and 10% hydrogen--are thought to form at heliocentric distances of 10-25 AU on closely packed orbits spaced ~5 Hill radii apart. Such oligarchies are ultimately unstable. Once the parent disk of planetesimals is sufficiently depleted, oligarchs perturb one another onto crossing orbits

E. N. Kirby, P. Guhathakurta, S. M. Faber, D. C. Koo

We present two methods for determining spectroscopic redshifts of galaxies in the DEEP2 survey which display only one identifiable feature, an emission line, in the observed spectrum ("single-line galaxies"). First, we assume each single line is one of the four brightest lines accessible to DEEP2: Halpha, [OIII] 5007, Hbeta, or [OII] 3727. Then, we s

C. Scarlata, C. M. Carollo, S. J. Lilly, R. Feldmann

ABRIDGED: We study the evolution since z~1 of the rest-frame B luminosity function of the early-type galaxies (ETGs) in ~0.7 deg^2 in the COSMOS field. In order to identify ALL progenitors of local ETGs we construct the sample of high-z galaxies using two complementary criteria: (i) A morphological selection based on the Zurich Estimator of Structural Types,

Thomas Klose, Konstantin Zarembo

We compute one-loop S-matrix in the reduced sigma-model which describes AdS_5 x S^5 string theory in the near-flat-space limit. The result agrees with the corresponding limit of the S-matrix in the full sigma-model, which demonstrates the consistency of the reduction at the quantum level.

Roger E. Behrend

The combinatorics of certain osculating lattice paths is studied, and a relationship with oscillating tableaux is obtained. More specifically, the paths being considered have fixed start and end points on respectively the lower and right boundaries of a rectangle in the square lattice, each path can take only unit steps rightwards or upwards, and two differe

Luis O. Silva, Julio H. Toloza

The classical Kramer sampling theorem establishes general conditions that allow the reconstruction of functions by mean of orthogonal sampling formulae. One major task in sampling theory is to find concrete, non trivial realizations of this theorem. In this paper we provide a new approach to this subject on the basis of the M. G. Krein's theory of repres

S. Deser, Bayram Tekin

We propose a novel but natural definition of conserved quantities for gravity models quadratic and higher in curvature. Based on the spatial asymptotics of curvature rather than of metric, it avoids the GR energy machinery's more egregious problems--such as zero energy "theorems" and failure in flat backgrounds -- in this fourth-derivative realm.

Pascal Tesson, Denis Therien

The study of finite automata and regular languages is a privileged meeting point of algebra and logic. Since the work of Buchi, regular languages have been classified according to their descriptive complexity, i.e. the type of logical formalism required to define them. The algebraic point of view on automata is an essential complement of this classification:

K. A. Arnaud, G. Auger, S. Babak, J. Baker

The Mock LISA Data Challenges (MLDCs) have the dual purpose of fostering the development of LISA data analysis tools and capabilities, and demonstrating the technical readiness already achieved by the gravitational-wave community in distilling a rich science payoff from the LISA data output. The first round of MLDCs has just been completed: nine data sets co

Adam S. Bolton, Scott Burles, Tommaso Treu, Leon V. E. Koopmans

We combine strong-lensing masses with SDSS stellar velocity dispersions and HST-ACS effective (half-light) radii for 36 lens galaxies from the Sloan Lens ACS (SLACS) Survey to study the mass dependence of mass-dynamical structure in early-type galaxies. We find that over a 180--390 km/s range in velocity dispersion, structure is independent of lensing mass t

G. Maillard, T. Mountford

We study the decay rate of large deviation probabilities of occupation times, up to time $t$, for the voter model $η\colon\Z^2\times[0,\infty)\ra\{0,1\}$ with simple random walk transition kernel, starting from a Bernoulli product distribution with density $ρ\in(0,1)$. Bramson, Cox and Griffeath (1988) showed that the decay rate order lies in $[\log(t),\log^

Alexander Nagel, Elias Stein

The purpose of this paper is to prove optimal estimates for solutions of the Kohn-Laplacian for certain classes of model domains in several complex variables. This will be achieved by applying a type of singular integral operator whose novel features (related to product theory and flag kernels) differ essentially from the more standard Calderon-Zygmund opera

R. F. Sawyer

We investigate some features of the hydrodynamics and neutrino physics in the (predominantly) electron-positron plasma above a hyperaccreting disk (or torus) around a black hole, a conjectured engine for a short gamma ray burst. We suggest a possible scenario in which plasma in the region very near the black hole, energetically driven by neutrino annihilatio

Xavier Andrade, Silvana Botti, Miguel A. L. Marques, Angel Rubio

We present an efficient perturbative method to obtain both static and dynamic polarizabilities and hyperpolarizabilities of complex electronic systems. This approach is based on the solution of a frequency dependent Sternheimer equation, within the formalism of time-dependent density functional theory, and allows the calculation of the response both in reson

Vladimir Tolstykh

Dyer and Formanek (1976) proved that if N is a free nilpotent group of class two and of finite rank which is not equal to 1, or to 3, then the automorphism group Aut(N) of N is complete. The main result of the present paper states that the automorphism group of any infinitely generated free nilpotent group of class two is also complete.

Helen V. Gomonay, Vadim M. Loktev

It is of common knowledge that the direction of easy axis in the finite-size ferromagnetic sample is controlled by its shape. In the present paper we show that a similar phenomenon should be observed in the compensated antiferromagnets with strong magnetoelastic coupling. Destressing energy which originates from the long-range magnetoelastic forces is analog

Brad M. S. Hansen, Jay Anderson, James Brewer, Aaron Dotter

We present the results of a deep Hubble Space Telescope (HST) exposure of the nearby globular cluster NGC6397, focussing attention on the cluster's white dwarf cooling sequence. This sequence is shown to extend over 5 magnitudes in depth, with an apparent cutoff at magnitude F814W=27.6. We demonstrate, using both artificial star tests and the detectabili

J. P. de Lima, L. L. Goncalves, T. F. A. Alves

The static and dynamic properties of the anisotropic XY-model $(s=1/2)$ on the inhomogeneous periodic chain, composed of $N$ cells with $n$ different exchange interactions and magnetic moments, in a transverse field $h,$ are determined exactly at arbitrary temperatures. The properties are obtained by introducing the Jordan-Wigner fermionization and by reduci

C. Kevin Xu, David Shupe, Veronique Buat, Michael Rowan-Robinson

We study dust attenuation and stellar mass of $\rm z\sim 0.6$ star-forming galaxies using new SWIRE observations in IR and GALEX observations in UV. Two samples are selected from the SWIRE and GALEX source catalogs in the SWIRE/GALEX field ELAIS-N1-00 ($Ω= 0.8$ deg$^2$). The UV selected sample has 600 galaxies with photometric redshift (hereafter photo-z) $0

Davide Forcella, Amihay Hanany, Alberto Zaffaroni

We show how it is possible to use the plethystic program in order to compute baryonic generating functions that count BPS operators in the chiral ring of quiver gauge theories living on the world volume of D branes probing a non compact CY manifold. Special attention is given to the conifold theory and the orbifold C^2/Z_2 times C, where exact expressions fo

Jaroslaw Buczynski

We construct a family of examples of Legendrian subvarieties in some projective spaces. Although most of them are singular, a new example of smooth Legendrian variety in dimension 8 is in this family. The 8-fold has interesting properties: it is a compactification of the special linear group, a Fano manifold of index 5 and Picard number 1.

Zoran Škoda

A heap is a structure with a ternary operation which is intuitively a group with forgotten unit element. Quantum heaps are associative algebras with a ternary cooperation which are to the Hopf algebras what heaps are to groups, and, in particular, the category of copointed quantum heaps is isomorphic to the category of Hopf algebras. There is an intermediate

Alexey M. Kulik

The mild sufficient conditions for exponential ergodicity of a Markov process, defined as the solution to SDE with a jump noise, are given. These conditions include three principal claims: recurrence condition R, topological irreducibility condition S and non-degeneracy condition N, the latter formulated in the terms of a certain random subspace of \Re^m, as

Raymond Fresard, Henni Ouerdane, Thilo Kopp

We establish a correspondence between the resummation of world lines and the diagonalization of the Hamiltonian for a strongly correlated electronic system. For this purpose, we analyze the functional integrals for the partition function and the correlation functions invoking a slave boson representation in the radial gauge. We show in the spinless case that

M. L. Cowan, D. Anache-Ménier, W. K. Hildebrand, J. H. Page

Temporal fluctuations in the phase of waves transmitted through a dynamic, strongly scattering, mesoscopic sample are investigated using ultrasonic waves, and compared with theoretical predictions based on circular Gaussian statistics. The fundamental role of phase in Diffusing Acoustic Wave Spectroscopy is revealed, and phase statistics are also shown to pr

Susanne Pielawa, Giovanna Morigi, David Vitali, Luiz Davidovich

We propose a scheme for generating two-mode squeezing in high-Q resonators using a beam of atoms with random arrival times, which acts as a reservoir for the field. The scheme is based on four-wave mixing processes leading to emission into two cavity modes, which are resonant with the Rabi sidebands of the atomic dipole transition, driven by a saturating cla

Daniel Boer, Andre Utermann, Erik Wessels

Phenomenological models of the dipole cross section that enters in the description of for instance deep inelastic scattering at very high energies have had considerable success in describing the available small-x data in both the saturation region and the so-called extended geometric scaling (EGS) region. We investigate to what extent such models are compati

Adam J. Schwarz, Alessandro Gozzi, Angelo Bifone

We present an approach to study functional segregation and integration in the living brain based on community structure decomposition determined by maximum modularity. We demonstrate this method with a network derived from functional imaging data with nodes defined by individual image pixels, and edges in terms of correlated signal changes. We found communit

Marc-André Malouin, Fedwa El-Mellouhi, Normand Mousseau

Ga interstitials in GaAs ($I_{Ga}$) are studied using the local-orbital {ab-initio} code SIESTA in a supercell of {216+1} atoms. Starting from eight different initial configurations, we find five metastable structures: the two tetrahedral sites in addition to the 110-split$\mathrm{_{[Ga-As]}}$, 111-split$\mathrm{_{[Ga-As]}}$, and 100-split$\mathrm{_{[Ga-Ga]}

Ugur Tirnakli, Christian Beck, Constantino Tsallis

We investigate the probability density of rescaled sums of iterates of deterministic dynamical systems, a problem relevant for many complex physical systems consisting of dependent random variables. A Central Limit Theorem (CLT) is only valid if the dynamical system under consideration is sufficiently mixing. For the fully developed logistic map and a cubic

Yael Karshon, Christina Bjorndahl

A theorem of Tietze and Nakamija, from 1928, asserts that if a subset X of R^n is closed, connected, and locally convex, then it is convex. We give an analogous "local to global convexity" theorem when the inclusion map of X to R^n is replaced by a map from a topological space X to R^n that satisfies certain local properties. We say that a map from a

Kasper Peeters

Cadabra is a new computer algebra system designed specifically for the solution of problems encountered in field theory. It has extensive functionality for tensor polynomial simplification taking care of Bianchi and Schouten identities, for fermions and anti-commuting variables, Clifford algebras and Fierz transformations, implicit coordinate dependence, mul

M. Bessa, J. Rocha

This paper has been withdrawn by the authors due to a mistake in one of the proofs

Zoltan Fodor, Sandor D. Katz, Christian Schmidt

We study the QCD phase diagram by first principle lattice calculations at so far unreached high densities. For this purpose we employ the density of states method. Unimproved staggered fermions, which describe four quark flavors in the continuum are used in this analysis. Though the method is quite expensive, small lattices show an indication for a triple-po

Ovidiu Costin, Stavros Garoufalidis

The fractional polylogarithms, depending on a complex parameter $\a$, are defined by a series which is analytic inside the unit disk. After an elementary conversion of the series into an integral presentation, we show that the fractional polylogarithms are multivalued analytic functions in the complex plane minus 0 and 1. For non-integer values of $\a$, we p

K. Schoenhammer

Exact numerical results for the full counting statistics (FCS) for a one-dimensional tight-binding model of noninteracting electrons are presented without using an idealized measuring device. The two initially separate subsystems are connected at t=0 and the exact time evolution for the large but finite combined system is obtained numerically. At zero temper

Richard B. Larson

Although the basic physics of star formation is classical, numerical simulations have yielded essential insights into how stars form. They show that star formation is a highly nonuniform runaway process characterized by the emergence of nearly singular peaks in density, followed by the accretional growth of embryo stars that form at these density peaks. Circ

Jianguo Cao

In this paper, we study certain compact 4-manifolds with non-negative sectional curvature $K$. If $s$ is the scalar curvature and $W_+$ is the self-dual part of Weyl tensor, then it will be shown that there is no metric $g$ on $S^2 \times S^2$ with both (i) $K > 0$ and (ii) $ {1/6} s - W_+ \ge 0$. We also investigate other aspects of 4-manifolds with non-neg

Zhi-Ping Jin, Yi-Zhong Fan

We constrain the circum-burst medium profile with the rise behavior of the very early afterglow light curves of gamma-ray bursts (GRBs). Using this method, we find a constant and low-density medium profile for GRB 060418 and GRB 060607A, which is consistent with the inference from the late afterglow data. In addition, we show that the absence of the IR flash

Robert Fleischer

We discuss the theoretical interpretation of the $B\toπK$ system in the light of new data. Using the branching ratio and direct CP asymmetry of $B^0_d\toπ^-K^+$, the picture of the direct CP violation in $B_d^0\toπ^+π^-$ could be clarified: we predict $A_{CP}^{dir}(B_d\toπ^+π^-)=-0.24\pm0.04$, which favours the BaBar measurement, and extract $γ=(70.0^{+3.8}_

Sergei V. Zhukovsky, Dmitry N. Chigrin, Andrei V. Lavrinenko, Johann Kroha

We propose the new concept of a switchable multimode microlaser. As a generic, realistic model of a multimode microresonator a system of two coupled defects in a two-dimensional photonic crystal is considered. We demonstrate theoretically that lasing of the cavity into one selected resonator mode can be caused by injecting an appropriate optical pulse at the

Robin Pemantle

Consider a binary tree, to the vertices of which are assigned independent Bernoulli random variables with mean $p\leq1/2$. How many of these Bernoullis one must look at in order to find a path of length $n$ from the root which maximizes, up to a factor of $1-ε$, the sum of the Bernoullis along the path? In the case $p=1/2$ (the critical value for nontriviali

R. L. S. Farias, N. C. Cassol-Seewald, G. Krein, R. O. Ramos

The nonequilibrium effective equation of motion for a scalar background field in a thermal bath is studied numerically. This equation emerges from a microscopic quantum field theory derivation and it is suitable to a Langevin simulation on the lattice. Results for both the symmetric and broken phases are presented.

Tetsufumi Hirano, Ulrich W. Heinz, Dmitri Kharzeev, Roy Lacey

We investigate the robustness of the discovery of the perfect fluid through comparison of hydrodynamic calculations with the elliptic flow coefficient v_2 at midrapidity in Au+Au collisions at sqrt{s_{NN}}=200 GeV. Employing the Glauber model for initial entropy density distributions, the centrality dependence of v_2 is reasonably reproduced by using an idea

Sara Bergkvist, Robert Saers, Emil Lundh, Anders Rosengren

A two-dimensional system of atoms in an anisotropic optical lattice is studied theoretically. If the system is finite in one direction, it is shown to exhibit a transition between a two-dimensional superfluid and a one-dimensional Mott insulating chain of superfluid tubes. Monte Carlo simulations are consistent with the expectation that the phase transition

Marco Zambon

We show that certain submanifolds of generalized complex manifolds ("weak branes") admit a natural quotient which inherits a generalized complex structure. This is analog to quotienting coisotropic submanifolds of symplectic manifolds. In particular Gualtieri's generalized complex submanifolds ("branes") quotient to space-filling branes.

J. Dias de Deus, J. G. Milhano

We explore the relationship between the Glasma framework and the String Percolation Model by introducing a simple model for the rapidity distributions in nucleus-nucleus collisions. The model is solved for both symmetrical and asymmetrical collisions. The phenomenon of limiting fragmentation is briefly discussed.

Constantin V. Usenko, Nataliia O. Cherkashyna

It is shown that relative coordinate and momentum of coherent electron pair have the meaning of observables with the help of quadrupole and magnetic moments. Distributions of quadrupole terms of scalar potential are shown. These distributions have nonclassical properties.

Oriol Vendrell, Fabien Gatti, Hans-Dieter Meyer

The dynamics and infrared absorption spectrum of the protonated water dimer are reported by full quantum simulation. Strong couplings between the spectroscopically active proton-transfer motion and low-frequency, large-amplitude torsional modes are clearly identified and their role in the cluster dynamics is explained. These couplings are responsible for the

Gustavo A. Fernandez-Alcober, Ilya V. Kazachkov, Vladimir N. Remeslennikov, Peter Symonds

We address the following question. For which finitely generated pro-$p$ groups the comparison map $ϕ^2:H_{cont}^{2}(P,\F_p) \to H_{disc}{2}(P,\F_p)$ is an isomorphism? We prove that if $P$ is not finitely presented then $ϕ^2$ is not surjective. Furthermore, if $P$ is finitely presented $ϕ^2$ is an isomorphism if and only if the comparison map $ϕ_2:H^{disc}_{

G. K. Sankaran

This paper is withdrawn because it is superseded by arXiv:0710.4284

Guido Cognola, Monica Gastaldi, Sergio Zerbini

Motivated by the dark energy issue, a minisuperspace approach to the stability for modified gravitational models in a four dimensional cosmological setting are investigated. Specifically, after revisiting the $f(R)$ case, $R$ being the Ricci curvature, we present a stability condition around a de Sitter solution valid for modified gravitational models of gen

P. Olesen

The question of whether the zero viscosity limit $ν\to 0$ is identical to the no viscosity $ν\equiv 0$ case is investigated in a simple shell (GOY) model with only three shells. We find that it is possible to express two velocities in terms of Bessel functions. The third velocity function acts as a background. The relevant Bessel functions are infinitely osc

Kasra Rafi, Saul Schleimer

We provide the first non-trivial examples of quasi-isometric embeddings between curve complexes. These are induced either by puncturing a closed surface or via orbifold coverings. As a corollary, we give new quasi-isometric embeddings between mapping class groups.

C. Hanhart, Yu. S. Kalashnikova, A. E. Kudryavtsev, A. V. Nefediev

In many calculations of the two--photon decay of hadronic molecules, the decay matrix element is estimated using the wave function at the origin prescription, in analogy to the two-photon decay of parapositronium. We question the applicability of this procedure to the two-photon decay of hadronic molecules for it introduces an uncontrolled model dependence i

Wan-Il Park, Ewan D. Stewart

We analyze how the spectrum of perturbations produced in a multi-component modular inflation model proposed by Kadota and Stewart depends on couplings between the two moduli. Although some simple direct couplings give essentially the same results as the original model, $dn/d\ln k \propto n-1$, simple indirect couplings produce a power law spectrum, $n-1 = \t

Keiju Murata, Jiro Soda, Sugumi Kanno

We investigate (2+1)-dimensional black strings in the Kaluza-Klein spacetime. The system is classically stable as long as the horizon size is much larger than the size of the compact space. Semiclassically, however, the horizon size shrinks gradually due to the energy loss through the Hawking radiation. Eventually, the system will enter into the regime of th

Qing-Quan Jiang, Shuang-Qing Wu, Xu Cai

Recently, Hawking radiation from a Schwarzschild-type black hole via gravitational anomaly at the horizon has been derived by Robinson and Wilczek. Their result shows that, in order to demand general coordinate covariance at the quantum level to hold in the effective theory, the flux of the energy momentum tensor required to cancel gravitational anomaly at t

E. V. Gorbar, Michio Hashimoto, V. A. Miransky

We study the dynamics in phases with vector condensates of gluons (gluonic phases) in dense two-flavor quark matter. These phases yield an example of dynamics in which the Higgs mechanism is provided by condensates of gauge (or gauge plus scalar) fields. Because vacuum expectation values of spatial components of vector fields break the rotational symmetry, i

S. Y. Li, Z. G. Si, Z. J. Yang

The inclusive production of doubly heavy baryons $Ξ_{cc}$ and $Ξ_{bb}$ at $γγ$ collider is investigated. It is found that the contribution from the heavy quark pair $QQ$ in color triplet and color sextet are important.

M. Mori, S. Hikino, S. Takahashi, S. Maekawa

We study the influence of magnetic scattering on the Josephson critical current, Ic, in a superconductor/ferromagnetic metal/superconductor (SFS) junction by a tunneling Hamiltonian approach. An analytical formula of Ic is given in the fourth order perturbation theory as regards the tunneling matrix element. The Ic exhibits the damped oscillatory dependence

Ying Chen, Chuan Liu, Yubin Liu, Jianping Ma

The excited states of charmonia are numerically investigated in quenched lattice QCD with improved gauge and Wilson fermion actions formulated on anisotropic lattices. Through a constrained curve fitting algorithm, the masses of the first excited states in $0^{++}$, $1^{++}$, and $1^{+-}$ channels are determined to be 3.825(88), 3.853(57), and 3.858(70) GeV,

Colin Guillarmou, Laurent Guillopé

For any orientable compact surface with boundary, we compute the regularized determinant of the Dirichlet-to-Neumann (DN) map in terms of particular values of dynamical zeta functions by using natural uniformizations, one due to Mazzeo-Taylor, the other to Osgood-Phillips-Sarnak. We also relate in any dimension the DN map for the Yamabe operator to the scatt

Mahan Mj

In earlier work, we had shown that Cannon-Thurston maps exist for Kleinian surface groups. In this paper we prove that pre-images of points are precisely end-points of leaves of the ending lamination whenever the Cannon-Thurston map is not one-to-one. In particular, the Cannon-Thurston map is finite-to-one. This completes the proof of the conjectural picture

Igor Belegradek

This is an expositiry article on collapsing theory in Riemannian geometry written for the Modern Encyclopedia of Mathematical Physics (MEMPhys). We focus on describing the geometric and topological structure of collapsed/non-collapsed regions in Riemannian manifold under various curvature assumptions. Numerous applications of collapsing theory to Riemannian

Rouzbeh Allahverdi, Andrew R. Frey, Anupam Mazumdar

The cosmological evolution of the string landscape is expected to consist of multiple stages of old inflation with large cosmological constant ending by tunnelling. Old inflation has a well known graceful exit problem as the observable universe becomes empty, devoid of any entropy. Simultaneously, in the quest for reheating the right degrees of freedom, it i

Wen Zhao, Donghui Xu

The evolution of the electric and magnetic components in an effective Yang-Mills condensate dark energy model is investigated. If the electric field is dominant, the magnetic component disappears with the expansion of the Universe. The total YM condensate tracks the radiation in the earlier Universe, and later it becomes $w_y\sim-1$ thus is similar to the co

S. de la Torre, O. Le Fevre, S. Arnouts, L. Guzzo

By combining the VVDS with the SWIRE data, we have built the currently largest spectroscopic sample of galaxies selected in the rest-frame near-infrared. These allow us to investigate, for the first time using spectroscopic redshifts, the clustering evolution of galaxies selected from their rest-frame near-infrared luminosity in the redshift range 0.2<z<2.1.

M. P. Almeida, F. de Melo, M. Hor-Meyll, A. Salles

We demonstrate the difference between local, single-particle dynamics and global dynamics of entangled quantum systems coupled to independent environments. Using an all-optical experimental setup, we show that, while the environment-induced decay of each system is asymptotic, quantum entanglement may suddenly disappear. This &#34;sudden death&#34; constitute

Prakash Gupta, Anirban Pathak

A clear physical meaning of the Carruthers-Nieto symmetric quantum phase fluctuation parameter (U) has been provided in Susskind Glogower and Barnett Pegg formalism of quantum phase and it is shown that the reduction of phase fluctuation parameter U with respect to its coherent state value corresponds to an antibunched state. Thus nonclassicality of a state