April 2006 arXiv papers — page 30

D. Rodriguez-Perez, Oscar Sotolongo-Grau, Ramon Espinosa Riquelme, Oscar Sotolongo-Costa

We model the interaction between the immune system and tumor cells including a time delay to simulate the time needed by the latter to develop a chemical and cell mediated response to the presence of the tumor. The results are compared with those of a previous paper, concluding that the delay introduces new instabilities in the system leading to an uncontrol

S. Esposito

An account is given of some topical unpublished work by Ettore Majorana, revealing his very deep intuitions and skilfulness in Theoretical Physics. The relevance of the quite unknown results obtained by him is pointed out as well.

Alexander G. Kyriakos

The purpose of present paper is to develop the approach to calculation of the mass spectra of elementary particles within the framework of the resonance theory of elementary particles as de Broglie waves

U. D. Jentschura, S. Kotochigova, E. -O. Le Bigot, P. J. Mohr

We combine a limited number of accurately measured transition frequencies in hydrogen and deuterium, recent quantum electrodynamics (QED) calculations, and, as an essential additional ingredient, a generalized least-squares analysis, to obtain precise and optimal predictions for hydrogen and deuterium transition frequencies. Some of the predicted transition

L. Praxmeyer, K. Wodkiewicz

We extend the theory of Talbot revivals for planar or rectangular geometry to the case of cylindrical waveguides. We derive a list of conditions that are necessary to obtain revivals in cylindrical waveguides. A phase space approach based on the Wigner and the Kirkwood-Rihaczek functions provides a pictorial representation of TM modes interference associated

L. Noethe, H. M. Adorf

Phase steps are an important type of wavefront aberrations generated by large telescopes with segmented mirrors. In a closed-loop correction cycle these phase steps have to be measured with the highest possible precision using natural reference stars, that is with a small number of photons. In this paper the classical Fisher information of statistics is used

A. Bret

We present an investigation of the electromagnetic instabilities which are trig gered when an ultra relativistic electron beam passes through a plasma. The linear growth rate is computed for every direction of propagation of the unstable modes, and temperatures are modelled using simple waterbag distribution functions. The ultra relativistic unstable spectru

Sebastien Chenais, Sebastien Forget, Marie-Claude Castex

A novel approach is used to enhance by nearly two orders of magnitude the conversion efficiency of a 125 nm-coherent source, based on four-wave mixing in room-temperature mercury vapor. Saturation issues are observed and discussed.

Andrei P. Kirilyuk

This report provides a brief review of recently developed extended framework for fundamental physics, designated as Quantum Field Mechanics and including causally complete and intrinsically unified theory of explicitly emerging elementary particles, their inherent properties, quantum and relativistic behaviour, interactions and their results. Essential progr

Goran Faldt, Ulla Tengblad, Colin Wilkin

The cross section for the dd -> 4He pi pi reaction is estimated near threshold in a two-step model where a pion created in a first interaction produces a second pion in a subsequent interaction. This approach, which describes well the rates of 2pi and eta production in the pd -> 3He pi pi and dd -> 4He eta reactions, leads to predictions that are much too lo

M. Hedayati-Poor, H. S. Sherif

A relativistic non-local model for the inclusive photoproduction of $η$ mesons from complex nuclei is introduced. The model is based on the dominance of the S$_{11}$(1535) resonance. We compare the results of our calculations with the available data on inclusive cross sections for the nuclei C, Al and Cu. Assuming the resonance propagates freely in the nucle

N. A. Kostov

Spectral method related to Lame equation with finite-gap potential is used to study the optical cascading equations. These equations are known not to be integrable by inverse scattering method. Due to "partial integrability" two-gap solutions are obtained in terms of products of elliptic functions and are classified in five different families related

Y. Chung, T. Schaefer

We study the propagation of ultra-short pulses in a cubic nonlinear medium. Using multiple-scale technique, we derive a new wave equation that preserves the nonlocal dispersion present in Maxwell's equations. As a result, we are able to understand how ultra-short nonlinear shocks are stabilized by dispersive terms. A delicate balance between dispersion a

Amir Leshem

In this paper we prove that given a black box assumed to generate bits of a given non-recursive real $Ω$ there is no computable decision procedure generating sequences of decisions such that if the output is indeed $Ω$ the process eventually accepts the hypothesis while if the output is different than $Ω$ than the procedure will eventually reject the hypothe

Wlodzimierz M. Tulczyjew

Standandard Hamiltonian mechanics in its homogeneous formulation is applied to the study of discontinuities representing rapid changes of Hamiltonians. Different formulations of Hamiltonian mechanics are reviewed. An original representation of a positive homogeneous Hamiltonian system by an outer oriented coisotropic submanifold of the phase space is propose

Jorge Sotomayor, Luis Fernando Mello, Denis de Carvalho Braga

In this paper we study the Lyapunov stability and Hopf bifurcation in a system coupling a Watt-centrifugal-governor with a steam-engine. Sufficient conditions for the stability of the equilibrium state in terms of the physical parameters and of the bifurcating periodic orbit at most critical parameters on the bifurcation surface are given.

Mark Braverman, Michael Yampolsky

In this note we give answers to questions posed to us by J.Milnor and M.Shub, which shed further light on the structure of non-computable Julia sets.

Jacob Palis, Jean-Christophe Yoccoz

The purpose of this paper is to advance the knowledge of the dynamics arising from the creation and subsequent bifurcation of Poincaré heteroclinic cycles. The problem is central to dynamics: it has to be addressed if, for instance, one aims at describing the typical orbit behaviour of a typical system, thus providing a global scenario for the ensemble of dy

John E. Roberts, Giuseppe Ruzzi

What remains of a geometrical notion like that of a principal bundle when the base space is not a manifold but a coarse graining of it, like the poset formed by a base for the topology ordered under inclusion? Motivated by finding a geometrical framework for developing gauge theories in algebraic quantum field theory, we give, in the present paper, a first a

Larry Wasserman, Kathryn Roeder

The power of multiple testing procedures can be increased by using weighted p-values (Genovese, Roeder and Wasserman 2005). We derive the optimal weights and we show that the power is remarkably robust to misspecification of these weights. We consider two methods for choosing weights in practice. The first, external weighting, is based on prior information.

Joseph P. S. Kung, Hal Schenck

Let A be an n by d matrix having full rank n. An orthogonal dual A^{\perp} of A is a (d-n) by d matrix of rank (d-n) such that every row of A^{\perp} is orthogonal (under the usual dot product) to every row of A. We define the orthogonal dual for arrangements by identifying an essential (central) arrangement of d hyperplanes in n-dimensional space with the n

Louis Boutet de Monvel

We show that the logarithmic trace of generalized Szegö projectors on compact contact manifolds vanishes identically.

Ronaldo Garcia, Jaume Llibre, Jorge Sotomayor

In this paper are determined the principal curvatures and principal curvature lines on canal surfaces which are the envelopes of families of spheres with variable radius and centers moving along a closed regular curve in R^3. By means of a connection of the differential equations for these curvature lines and real Riccati equations, it is established that ca

Guido Gentile, Michele V. Bartuccelli, Jonathan H. B. Deane

We consider a class of ordinary differential equations describing one-dimensional analytic systems with a quasi-periodic forcing term and in the presence of damping. In the limit of large damping, under some generic non-degeneracy condition on the force, there are quasi-periodic solutions which have the same frequency vector as the forcing term. We prove tha

K. Storozhuk

Let $X$ be a real or complex Banach space and $T_t:X\to X$ is a power bounded operator (or a $C_0$-semigroup). If there exists a "occasionally" attracting compact subset K (for each x$ in unit ball $\liminf_n ρ(T^n x, K)=0$ then there exists attracting finite-dimensional subspace $L$ (for each x in X $\lim_n ρ(T^n x, L)=0$. Also we define the compact

Masaru Kada

A slalom is a sequence of finite sets of length omega. Slaloms are ordered by coordinatewise inclusion with finitely many exceptions. Improving earlier results of Mildenberger, Shelah and Tsaban, we prove consistency results concerning existence and non-existence of an increasing sequence of a certain type of slaloms which covers a bounded set of functions i

Donald Yau

We study homology and cohomology of triassociative algebras with non-trivial coefficients.

Paolo Bellingeri, Sylvain Gervais, John Guaschi

We determine the lower central series and corresponding residual properties for braid groups and pure braid groups of orientable surfaces.

B. Feigin, M. Jimbo, T. Miwa, E. Mukhin

Let \{M_{r,s}\}_{0< r < p, 0< s < p&#39;} be the irreducible Virasoro modules in the $(p,p&#39;)$-minimal series. In our previous paper, we have constructed a monomial basis of \oplus_{r=1}^{p-1}M_{r,s} in the case of $1<p&#39;/p<2$. By `monomials&#39; we mean vectors of the form ϕ^{(r_L,r_{L-1})}_{-n_L}...ϕ^{(r_1,r_{0})}_{-n_1} |r_0,s >, where ϕ_{-n}^{(r&#3

Natalia Castellana, Juan A. Crespo, Jerome Scherer

We characterize Hopf spaces with finitely generated cohomology as an algebra over the Steenrod algebra. We &#34;deconstruct&#34; the original space into an H-space Y with finite mod p cohomology and a finite number of p-torsion Eilenberg-Mac Lane spaces. We give a precise description of homotopy commutative H-spaces in this setting.

A. Dymarsky, S. Gubser, Z. Guralnik, J. Maldacena

We study the dual gravity description of supersymmetric Wilson loops whose expectation value is unity. They are described by calibrated surfaces that end on the boundary of anti de-Sitter space and are pseudo-holomorphic with respect to an almost complex structure on an eight-dimensional slice of AdS_5 x S^5. The regularized area of these surfaces vanishes,

S. Bellucci, S. Krivonos, A. Shcherbakov

We demonstrate that in N=8 supersymmetric mechanics with linear and nonlinear chiral supermultiplets one may dualize two auxiliary fields into physical ones in such a way that the bosonic manifold will be a hyper-Kaehler one. The key point of our construction is about different dualizations of the two auxiliary components. One of them is turned into a physic

Samuel Webster

For five-dimensional braneworlds with an $S_1/\mathbb{Z}_2$ orbifold topology for the extra dimension $x^5$, we discuss the validity of recent claims that a gauge exists where the two boundary branes lie at fixed positions and the metric satisfies $g_{μ5}=\partial_5 g_{55}=0$ where $μ$ labels the transverse dimensions. We focus on models where the bulk is em

A. A. Slavnov

A systematic analysis of the unitary electroweak model described by the higher derivative Lagrangian depending on extra dimension [1] is presented.

Giovanna Davatz, Fabian Stoeckli, Charalampos Anastasiou, Guenther Dissertori

We study a phenomenological ansatz for merging next-to-next-to-leading order (NNLO) calculations with Monte Carlo event generators. We reweight them to match bin-integrated NNLO differential distributions. To test this procedure, we study the Higgs boson production cross-section at the LHC, for which a fully differential partonic NNLO calculation is availabl

Spencer Chang, Lawrence J. Hall, Neal Weiner

We present a supersymmetric realization of the twin Higgs mechanism, which cancels off all contributions to the Higgs mass generated above a scale f. Radiative corrections induced by the top quark sector lead to a breaking of the twin sector electroweak symmetry at a scale f ~ TeV. In our sector, below the scale f, these radiative corrections from the top qu

V. V. Khruschov

Methods of determination of constants of the Standard Model are considered. The constants values obtained now are presented and experiments for improving some values are pointed out. A few possible generalized models are considered together with their groups of gauge and kinematical symmetries.

Gino Isidori, Federico Mescia, Paride Paradisi, Christopher Smith

We present an extensive analysis of rare K decays, in particular of the two neutrino modes K+->pi+ nu nu-bar and KL->pi0 nu nu-bar, in the Minimal Supersymmetric extension of the Standard Model. We analyse the expectations for the branching ratios of these modes, both within the restrictive framework of the minimal flavour violation hypothesis and within a m

B. A. Kniehl, A. Onishchenko, J. H. Piclum, M. Steinhauser

In this paper we consider the matching coefficients up to two loops between Quantum Chromodynamics (QCD) and Non-Relativistic QCD (NRQCD) for the vector, axial-vector, scalar and pseudo-scalar currents. The structure of the effective theory is discussed and analytical results are presented. Particular emphasis is put on the singlet diagrams.

Stefan Weinzierl

A perturbative approach to quantum field theory involves the computation of loop integrals, as soon as one goes beyond the leading term in the perturbative expansion. First I review standard techniques for the computation of loop integrals. In a second part I discuss more advanced algorithms. For these algorithms algebraic methods play an important role. A s

Stefan Michalski

We study the restoration of chiral symmetry in linear sigma models with two quark flavors. The models taken into consideration have a U(2)_L x U(2)_R and an O(4) internal symmetry. The physical mesons of these models are sigma, pion, eta and a_0 where the latter two are not present in the O(4) model. Including two-loop contributions through sunset graphs we

The BABAR Collaboration, B. Aubert

We present a study of the decays B0bar --> D(*)0 K(*)0bar using a sample of 226 million Y(4S) --> B Bbar decays collected with the BaBar detector at the PEP-II asymmetric-energy e+e-collider at SLAC. We report evidence for the decay of B0 and B0bar mesons to the D*0 K0s final state with an average branching fraction BF(B0-tilde --> D*0 K0bar) := [ BF(B0bar -

M. Akbar

Static space times with maximal symmetric transverse spaces are classified according to their Ricci collineations. These are investigated for non-degenerate Ricci tensor ($det.(R_α) \neq 0$). It turns out that the only collineations admitted by these spaces can be ten, seven, six or four. Some new metrics admitting proper Ricci collineations are also investi

Eugeniy E. Mikhailov, Keisuke Goda, Thomas Corbitt, Nergis Mavalvala

We study the effects of frequency-dependent squeeze amplitude attenuation and squeeze angle rotation by electromagnetically induced transparency (EIT) on gravitational wave (GW) interferometers. We propose the use of low-pass, band-pass, and high-pass EIT filters, an S-shaped EIT filter, and an intra-cavity EIT filter to generate frequency-dependent squeezin

Amos Lapidoth, Ligong Wang

The capacity of non-coherent stationary Gaussian fading channels with memory under a peak-power constraint is studied in the asymptotic weak-signal regime. It is assumed that the fading law is known to both transmitter and receiver but that neither is cognizant of the fading realization. A connection is demonstrated between the asymptotic behavior of channel

Richard J. Barton

We consider the problem of adaptive modulation for wideband DS-CDMA Rayleigh fading channels with imperfect channel state information (CSI). We assume a multidimensional signal subspace spanned by a collection of random spreading codes (multicoding) and study the effects of both the subspace dimension and the probability distribution of the transmitted symbo

Tie Liu, Pramod Viswanath

Two new proofs of the Fisher information inequality (FII) using data processing inequalities for mutual information and conditional variance are presented.

Majid Khayari, Stéphane Schneider, Isabelle Kramer, Laurent Romary

This paper presents the TermSciences portal, which deals with the implementation of a conceptual model that uses the recent ISO 16642 standard (Terminological Markup Framework). This standard turns out to be suitable for concept modeling since it allowed for organizing the original resources by concepts and to associate the various terms for a given concept.

Damiano Bolzoni, Sandro Etalle

We present APHRODITE, an architecture designed to reduce false positives in network intrusion detection systems. APHRODITE works by detecting anomalies in the output traffic, and by correlating them with the alerts raised by the NIDS working on the input traffic. Benchmarks show a substantial reduction of false positives and that APHRODITE is effective also

Di Xiao, Junren Shi, Qian Niu

The Comment by Duval et al. [PRL 96, 099701 (2006)] addresses an important, but not the main, result of our Letter [PRL 95, 137204 (2005)]. It does not contradict our results in substance, and the only objection is really on the style of approach.

Manuel Torres, Alejandro Kunold

In this work we study the microwave photoconductivity of a two-dimensional electron system (2DES) in the presence of a magnetic field and a two-dimensional modulation (2D). The model includes the microwave and Landau contributions in a non-perturbative exact way, the periodic potential is treated perturbatively. The Landau-Floquet states provide a convenient

Tanmoy Das, R. S. Markiewicz, A. Bansil

Recent experiments on Pr$_{0.89}$LaCe$_{0.11}$CuO$_4$ observe an anisotropic spin-correlation gap and a nonmonotonic superconducting (SC) gap, which we analyze within the framework of a $t-t^{\prime}-t^{\prime\prime}-t^{\prime\prime\prime}-t^{iv}-U$ model with a $d_{x^2-y^2}$ pairing interaction including a third harmonic contribution. By introducing a reali

Yoichi Tanaka, Norio Kawakami

We study transport through double quantum dots coupled to normal and superconducting leads, where the Andreev reflection plays a key role in determining characteristic transport properties. We shall discuss two typical cases, i.e. double dots with serial or parallel geometry. For the parallel geometry, the interference of electrons via multiple paths is indu

C. Cattuto, R. Brito, U. Marini Bettolo Marconi, F. Nori

We have numerically investigated the behavior of driven non-cohesive granular media and found that two fixed large intruder particles, immersed in a sea of small particles, experience, in addition to a short range depletion force, a long range repulsive force. The observed long range interaction is fluctuation-induced and we propose a mechanism similar to th

Chenyu Wei

Temperature dependent conformations of linear polymer molecules adsorbed at carbon nanotube (CNT) interfaces are investigated through molecule dynamics simulations. Model polyethylene (PE) molecules are shown to have selective conformations on CNT surface, controlled by atomic structures of CNT lattice and geometric coiling energy. PE molecules form entropy

N. Bergeal, V. Dubost, Y. Noat, W. Sacks

We present scanning tunneling microscopy and spectroscopy of the newly discovered superconductor CaC$_6$. The tunneling conductance spectra, measured between 3 K and 15 K, show a clear superconducting gap in the quasiparticle density of states. The gap function extracted from the spectra is in good agreement with the conventional BCS theory with $Δ(0)$ = 1.6

R. J. Radwanski, Z. Ropka

In contrary to customarily consideration of the Jahn-Teller theorem for 3d-ion compounds in the orbital space only we point out that it has to be considered in the spin-orbital space. It is despite the weakness of the intraatomic spin-orbit coupling. A direct motivation for this paper is an erroneous claim of a recent Phys. Rev. Lett. 96 (2006) 027201 paper

J. Hass, C. A. Jeffrey, R. Feng, T. Li

With expanding interest in graphene-based electronics, it is crucial that high quality graphene films be grown. Sublimation of Si from the 4H-SiC(0001) Si-terminated) surface in ultrahigh vacuum is a demonstrated method to produce epitaxial graphene sheets on a semiconductor. In this paper we show that graphene grown from the SiC$(000\bar{1})$ (C-terminated)

S. N. Taraskin, S. I. Simdyankin, S. R. Elliott, J. R. Neilson

Using an analytical theory, experimental terahertz time-domain spectroscopy data and numerical evidence, we demonstrate that the frequency dependence of the absorption coupling coefficient between far-infrared photons and atomic vibrations in disordered materials has the universal functional form, C(omega) = A + B*omega^2, where the material-specific constan

Robert P. Smith, Anna Kusmartseva, Yuen T. C. Ko, Siddharth S Saxena

We have studied the evolution, with hydrostatic pressure, of the recently discovered superconductivity in the graphite intercalation compounds C$_6$Yb and C$_6$Ca. We present pressure-temperature phase diagrams, for both superconductors, established by electrical transport and magnetization measurements. In the range 0-1.2 GPa the superconducting transition

Vincenzo Vitelli, Julius B. Lucks, David R. Nelson

We study static and dynamical properties that distinguish two dimensional crystals constrained to lie on a curved substrate from their flat space counterparts. A generic mechanism of dislocation unbinding in the presence of varying Gaussian curvature is presented in the context of a model surface amenable to full analytical treatment. We find that glide diff

M. Takizawa, H. Wadati, K. Tanaka, M. Hashimoto

We have measured photoemission spectra of SrTiO3/LaTiO3 superlattices with a topmost SrTiO3 layer of variable thickness. Finite coherent spectral weight with a clear Fermi cut-off was observed at chemically abrupt SrTiO3/LaTiO3 interfaces, indicating that an ``electronic reconstruction&#39;&#39; occurs at the interface between the Mott insulator LaTiO3 and t

Andrei Borzdov, Dmitry Pozdnyakov, Vadim Galenchik, Vladimir Borzdov

Self-consistent calculations of acoustic and polar optical phonon scattering rates in GaAs quantum wire transistor structures were carried out with account of collisional broadening. The influence of the gate bias on the scattering rates was examined, too. It was shown that in order to treat the scattering rates rigorously it is important to search for elect

Isabelle Cantat, Celine Poloni, Renaud Delannay

Liquid foam flows in a Hele-Shaw cell were investigated. The plug flow obtained for a monodisperse foam is strongly perturbed in the presence of bubbles whose size is larger than the average bubble size by an order of magnitude at least. The large bubbles migrate faster than the mean flow above a velocity threshold which depends on its size. We evidence expe

Ekaterina Grancharova

We propose a new approach to the self-consistency equation, which arises in the problem of the motion of a hole in a quantum antiferromagnet, appropriate to the case of small exchange energy $J$. The functional equation for the Green function is transformed into a differential equation; its solutions are analyzed and compared to the existing numerical calcul

Kenji Yonemitsu

Dynamics of ionic-to-neutral and neutral-to-ionic phase transitions induced by intrachain charge-transfer photoexcitations are studied in a quasi-one-dimensional extended Hubbard model with alternating potentials and an electron-lattice coupling for mixed-stack charge-transfer complexes. For interchain couplings, we use electron-electron interactions previou

Nobuya Maeshima, Kouichi Okunishi, Kiyomi Okamoto, Tôru Sakai

We study an incommensurate long-range order induced by an external magnetic field in a quasi-one-dimensional bond-alternating spin system, F5PNN, focusing on the role of the frustrating interaction which can be enhanced by a high-pressure effect. On the basis of the density matrix renormalization group analysis of a microscopic model for F5PNN, we present se

Sh. E. Kekutia, N. D. Chkhaidze

The problem studied in this paper is to obtain the equations describing sound propagation in a consolidated porous medium filled with superfluid, determine the elastic coefficients, appearing in the equations, in terms of physically measurable quantities, and calculate the propagation velocities of transverse and longitudinal waves at high and low oscillatin

Priya Sony, Alok Shukla

In this paper we present an approach aimed at calculating the optical dielectric constant of crystalline insulators both at the Hartree-Fock, and correlated levels. Our scheme employs a real-space methodology, employing Wannier functions as the basic building blocks. The scheme has been applied to compute the optical dielectric constants of LiF, LiCl, MgO, a

Yan Chen, T. M. Rice, F. C. Zhang

For reasonable parameters a hole bound to a Na^{+} acceptor in Ca_{2-x}Na_{x}CuO_{2}Cl_{2} has a doubly degenerate ground state whose components can be represented as states with even (odd) reflection symmetry around the x(y) -axes. The conductance pattern for one state is anisotropic as the tip of a tunneling microscope scans above the Cu-O-Cu bonds along t

Jing-Min Hou, Li-Jun Tian, Shuo Jin

We propose a scheme to realize coherent control of spin states of molecule magnet, Ni$_4$. We introduce transverse magnetic fields with special frequencies. When the frequencies of transverse magnetic fields match in some conditions, we obtain dark states in Ni$_4$ molecules. Through adjusting the magnitude of magnetic fields, we can obtain any arbitrary sup

C. Van den Broeck, R. Kawai

Onsager symmetry implies that a Brownian motor, driven by a temperature gradient, will also perform a refrigerator function upon loading. We analytically calculate the corresponding heat flux for an exactly solvable microscopic model and compare it with molecular dynamics simulations.

Stefano Ciliberti, Paolo De Los Rios, Francesco Piazza

Vibrational spectra of proteins and topologically disordered solids display a common anomaly at low frequencies, known as Boson peak. We show that such feature in globular proteins can be deciphered in terms of an energy landscape picture, as it is for glassy systems. Exploiting the tools of Euclidean random matrix theory, we clarify the physical origin of s

Sze-Shiang Feng, Mogus Mochena

The zinc-blende GaAs-based III-V diluted magnetic semiconductors (DMS)are studied in the coherent potential approximation(CPA). In this work, we use the exact Hilbert transformation of the face-centered cubic(fcc) density of states (DOS), which is different from the usual semi-circle density of states employed in our previous work. Our calculated relation of

Jerome Esteve, Jean-Baptiste Trebbia, Thorsten Schumm, Alain Aspect

We report in situ measurements of density fluctuations in a quasi one dimensional Bose gas at thermal equilibrium in an elongated harmonic trap. We observe an excess of fluctuations compared to the shot noise level expected for uncorrelated atoms. At low atomic density, the measured excess is in good agreement with the expected bunching for an ideal Bose gas

Yuki Watanabe, Eiichiro Komatsu

We show that the energy density spectrum of the primordial gravitational waves has characteristic features due to the successive changes in the relativistic degrees of freedom during the radiation era. These changes make the evolution of radiation energy density deviate from the conventional adiabatic evolution, ρ_r~ a^{-4}, and thus cause the expansion rate

Crystal L. Martin

The kinematics of neutral gas and warm ionized gas have been mapped in one-dimension across ultraluminous starburst galaxies using interstellar absorption and emission lines, in Keck II ESI spectra. Blue-shifted absorption is found along more of the slit than anticipated, exceeding scales of 15 kpc across several systems. The large velocity gradient measured

Hans Van Winckel, Tom Lloyd Evans, Maarten Reyniers, Pieter Deroo

In this contribution we give a progress report on our systematic study of a large sample of post-AGB stars. The sample stars were selected on the basis of their infrared colours and the selection criteria were tuned to discover objects with hot dust in the system. We started a very extensive, multi-wavelength programme which includes the analysis of our radi

Robert A. Wittenmyer, Michael Endl, William D. Cochran, Artie P. Hatzes

Based on the long-term radial-velocity surveys carried out with the McDonald Observatory 2.7m Harlan J. Smith Telescope from 1988 to the present, we derive upper limits to long-period giant planet companions for 31 nearby stars. Data from three phases of the McDonald Observatory 2.7m planet-search program have been merged together and for 17 objects, data fr

I. Rogachevskii, N. Kleeorin, A. D. Chernin, E. Liverts

A new mechanism of generation of large-scale magnetic fields in colliding protogalactic clouds and merging protostellar clouds is discussed. Interaction of the colliding clouds produces large-scale shear motions which are superimposed on small-scale turbulence. Generation of the large-scale magnetic field is due to a &#39;&#39;shear-current&#34; effect (or &

S. Cortiglioni, E. Carretti

The B-mode detection of Cosmic Microwave Background polarization will require new technological developments, able to get sensitivities at least 2 orders of magnitude better than for the E-mode. This really ambitious goal cannot be reached simply by either improving the present technology or by adding more detectors to current design, at least in the frame o

Renaud Papoular

A numerical simulation of vibrational excitation of molecules was devised, and used to excite computational models of common molecules into a prescribed, pure, normal vibration mode in the ground electronic state, with varying, controlable energy content. The redistribution of this energy (either non-chaotic or irreversible IVR) within the isolated, free mol

Justin R. Crepp, Jian Ge, Andrew D. Vanden Heuvel, Shane P. Miller

We have built a series of notch filter image masks that make the Lyot coronagraph less susceptible to low-spatial-frequency optical aberrations. In this paper, we present experimental results of their performance in the lab using monochromatic light. Our tests show that these ``eighth-order&#39;&#39; masks are resistant to tilt and focus alignment errors, an

E. Chiosi, A. Vallenari, E. V. Held, L. Rizzi

In this paper we discuss the cluster and field star formation in the central part of the Small Magellanic Cloud. The main goal is to study the correlation between young objects and their interstellar environment. The ages of about 164 associations and 311 clusters younger than 1 Gyr are determined using isochrone fitting. The spatial distribution of the clus

Alfonso Trejo, Luis F. Rodriguez

An extraordinarily massive cluster of red supergiants has been recently reported in the direction of the galactic coordinates $l = 25\rlap.^\circ3$; $b = -0\rlap.^\circ2$. This cluster is associated with an X-ray source, a very high-energy $γ$-ray source, and three bright non-thermal radio sources. The \sl a priori \rm probability of these associations being

Manami Sasaki, Roland Kothes, Paul P. Plucinsky, Terrance J. Gaetz

We report the detection of molecular clouds around the X-ray bright interior feature in the Galactic supernova remnant (SNR) CTB 109 (G109.1-1.0). This feature, called the Lobe, has been previously suggested to be the result of an interaction of the SNR shock wave with a molecular cloud complex. We present new high resolution X-ray data from the Chandra X-ra

Kaspar Arzner, Loukas Vlahos

We numerically explore electron acceleration and coronal heating by dissipative electric fields. Electrons are traced in linear force-free magnetic fields extrapolated from SOHO/MDI magnetograms, endowed with anomalous resistivity ($η$) in localized dissipation regions where the magnetic twist $\nabla \times \bhat$ exceeds a given threshold. Associated with

H. K. Eriksen, C. Dickinson, C. R. Lawrence, C. Baccigalupi

The quality of CMB observations has improved dramatically in the last few years, and will continue to do so in the coming decade. Over a wide range of angular scales, the uncertainty due to instrumental noise is now small compared to the cosmic variance. One may claim with some justification that we have entered the era of precision CMB cosmology. However, s

Flavio D&#39;Amico, Francisco Jablonski, Claudia V. Rodrigues, Deonisio Cieslinski

We report here on near infrared observations of the field around IGR J16358-4756. The source belongs to the new class of highly absorbed X-ray binaries discovered by IBIS/INTEGRAL. Our primary goal was to identify the infrared counterpart of the source, previously suggested to be a LMXB and then further reclassified as a HMXB. We have made use of Chandra obs

P. Sestito, S. Degl Innocenti, P. G. Prada Moroni, S. Randich

Recent 3-D analysis of the solar spectrum data suggests a significant change of the solar chemical composition. This may affect the temporal evolution of the surface abundance of light elements since the extension of the convective envelope is largely affected by the internal opacity value. We analyse the influence of the adopted solar mixture on the opacity

Manolis Plionis, Cinthia Ragone, Spyros Basilakos

In the hierarchical structure formation model cosmic halos are supposed to form by accretion of smaller units along anisotropic direction, defined by large-scale filamentary structures. After the epoch of primary mass aggregation (which depend on the cosmological model), violent relaxation processes will tend to alter the halo phase-space configuration produ

Andrei Mesinger, Greg Bryan, Zoltan Haiman

We use three-dimensional hydrodynamic simulations to investigate the effects of a transient photoionizing ultraviolet (UV) flux on the collapse and cooling of pregalactic clouds. These clouds have masses in the range 10^5 -10^7 M_sun, form at high redshifts (z>18), are assumed to lie within the short-lived cosmological HII regions around the first generation

Ralitsa L. Dragomirova, Branislav K. Nikolic

We generalize the scattering theory of quantum shot noise to include the full spin-density matrix of electrons injected from a spin-filtering or ferromagnetic electrode into a quantum-coherent nanostructure governed by various spin-dependent interactions. This formalism yields the spin-resolved shot noise power for different experimental measurement setups--

N. Kashikawa, K. Shimasaku, M. A. Malkan, M. Doi

We report an extensive search for Lyman-alpha emitters (LAEs) at z=6.5 in the Subaru Deep Field. Subsequent spectroscopy with Subaru and Keck identified eight more LAEs, giving a total of 17 spectroscopically confirmed LAEs at z=6.5. Based on this spectroscopic sample of 17, complemented by a photometric sample of 58 LAEs, we have derived a more accurate Lym

K. F. Tiampo, J. B. Rundle, W. Klein, J. Holliday

Numerical simulations have shown that certain driven nonlinear systems can be characterized by mean-field statistical properties often associated with ergodic dynamics [C.D. Ferguson, W. Klein, and J.B. Rundle, Phys. Rev. E 60, 1359 (1999); D. Egolf, Science 287, 101 (2000)]. These driven mean-field threshold systems feature long-range interactions and can b

David Pooley, Jeffrey A. Blackburne, Saul Rappaport, Paul L. Schechter

PG 1115+080 is a quadruply lensed quasar at z=1.72 whose image positions are well fit by simple models of the lens galaxy (at z=0.31). At optical wavelengths, the bright close pair of images exhibits a modest flux ratio anomaly (factors of ~1.2-1.4 over the past 22 years) with respect to these same models. We show here that as observed in X-rays with Chandra

Udo Baumgartner

Let $Γ$ be a group which is virtually free of rank at least 2 and let $\mathcal{F}_{td}(Γ)$ be the family of totally disconnected, locally compact groups containing $Γ$ as a co-compact lattice. We prove that the values of the scale function with respect to groups in $\mathcal{F}_{td}(Γ)$ evaluated on the subset $Γ$ have only finitely many prime divisors. Thi

Arnaud Koetsier, D. B. M. Dickerscheid, H. T. C. Stoof

We present the microscopic theory for the BEC-BCS crossover of an atomic Fermi gas in an optical lattice, showing that the Feshbach resonance underlying the crossover in principle induces strong multiband effects. Nevertheless, the BEC-BCS crossover itself can be described by a single-band model since it occurs at magnetic fields that are relatively far away

A. Ipp, K. Kajantie, A. Rebhan, A. Vuorinen

We present a new method for the evaluation of the perturbative expansion of the QCD pressure which is valid at all values of the temperature and quark chemical potentials in the deconfined phase and which we work out up to and including order g^4 accuracy. Our calculation is manifestly four-dimensional and purely diagrammatic -- and thus independent of any e

Tao Han, Bin Zhang

The Majorana nature of neutrinos may only be experimentally verified via lepton-number violating processes involving charged leptons. We explore the $ΔL=2$ like-sign dilepton production at hadron colliders to search for signals of Majorana neutrinos. We find significant sensitivity for resonant production of a Majorana neutrino in the mass range of 10-80 GeV