January 2006 arXiv papers — page 21

F. Labourie

We study Hitchin representations and maximal symplectic representations of surface groups, which can be both thought of as generalisations of Fuchsian representations. We show that the corresponding energy functionals are proper on Teichmuller space. We also prove that the mapping class group acts properly on the corresponding moduli spaces. These two result

Payman L Kassaei

We prove a gluing lemma for sections of line bundles on a rigid analytic variety. We apply the lemma, in conjunction with a result of Buzzard's, to give a proof of (a generalization) of Coleman's theorem which states that overconvergent modular forms of small slope are classical. The proof is "geometric" in nature, and is suitable for general

Andrei Moroianu

These notes, based on a graduate course I gave at Hamburg University in 2003, are intended to students having basic knowledges of differential geometry. Their main purpose is to provide a quick and accessible introduction to different aspects of Kähler geometry.

L. V. Belvedere, A. F. Rodrigues

The authors reexamine the two-dimensional model of massive fermions interacting with a massless pseudoscalar field via axial-current-pseudoscalar derivative coupling. Performing a canonical field transformation on the Bose field algebra the model is mapped into the Thirring model with an additional vector-current-scalar-derivative interaction (Schroer-Thirri

B. M. Barbashov, V. N. Pervushin

The Hamiltonian theory of a relativistic string is considered in a specific reference frame in terms the diffeo-invariant variables. The evolution parameter and energy invariant with respect to the time-coordinate transformations are constructed, so that the dimension of the kinemetric group of diffeomorphisms coincides with the dimension of a set of variabl

V. G. J. Rodgers, Takeshi Yasuda

In this note we demonstrate that the algebra associated with coordinate transformations might contain the origins of a scalar field that can behave as an inflaton and/or a source for dark energy. We will call this particular scalar field the diffeomorphism scalar field. In one dimension, the algebra of coordinate transformations is the Virasoro algebra while

Gordon P. Ramsey

The orbital angular momentum is one of the least understood of the spin characteristics of a proton. There are no direct ways to model the orbital angular momentum. However, the Jz=1/2 sum rule includes an angular momentum component and can provide indirect access to its properties. One of the other unknowns in the sum rule is the gluon polarization. We can

Andrea Banfi, Gavin P. Salam, Giulia Zanderighi

It is common, in both theoretical and experimental studies, to separately discuss quark and gluon jets. However, even at parton level, widely-used jet algorithms fail to provide an infrared safe way of making this distinction. We examine the origin of the problem, and propose a solution in terms of a new "flavour-kt" algorithm. As well as being of co

V. P. Goncalves, M. V. T. Machado

We report on our recent investigations in photonuclear production of heavy quarks and vector meson in ultraperipheral heavy ion collisions. In particular, our theoretical predictions are compared with the recent experimental measurements on coherent rho (STAR) and J/Psi (PHENIX) photoproduction at RHIC and estimates for LHC are given.

J. Bartels, S. Bondarenko, K. Kutak, L. Motyka

We examine, as a correction to the central exclusive Higgs boson production in $pp$ collisions at the LHC, the rescattering of gluonic ladders off the proton. As usual, at the lowest order the hard part of this process can be described as a fusion of two hard gluonic ladders. We calculate corrections to this hard amplitude which are due to rescattering of th

Michael J. Ramsey-Musolf, Shelley A. Page

Studies of the strangeness changing hadronic weak interaction have produced a number of puzzles that have so far evaded a complete explanation within the Standard Model. Their origin may lie either in dynamics peculiar to weak interactions involving strange quarks or in more general aspects of the interplay between strong and weak interactions. In principle,

Patrick Meade, Matthew Reece

If one takes naturalness seriously and also assumes a weakly coupled extension of the Standard Model (SM) then there are predictions for phenomenology that can be inferred in a model independent framework. The first such prediction is that there must be some colored particle with mass O(TeV) that cancels the top loop contribution to the quadratic divergence

Wilfried Buchmuller, Koichi Hamaguchi, Oleg Lebedev, Michael Ratz

In the standard model matter fields form complete representations of a grand unified group whereas Higgs fields belong to incomplete `split' multiplets. This remarkable fact is naturally explained by `local grand unification' in higher-dimensional extensions of the standard model. Here, the generations of matter fields are localized in regions of com

Michele Caselle, Martin Hasenbusch, Marco Panero

Motivated by the recent progress in the effective string description of the interquark potential in lattice gauge theory, we study interfaces with periodic boundary conditions in the three-dimensional Ising model. Our Monte Carlo results for the associated free energy are compared with the next-to-leading order (NLO) approximation of the Nambu-Goto string mo

Zoltan Ligeti

The first part of this talk reviews recent developments in flavor physics that can be made without detailed understanding of hadronic physics, driven by the data. The error of sin(2beta) has shrunk below 5%, and the measurements of alpha and gamma have reached interesting precisions. For the first time, there are significant constraints on the deviations fro

Krisztian Peters

We review hard diffractive results and prospects at the Tevatron with an emphasis on factorization breaking in diffractive processes. Upper limits on the exclusive di-jet and chi_c^0 production cross sections at CDF and the status of the D0 Forward Proton Detectors are discussed.

R. Lemrani, M. Robinson, V. A. Kudryavtsev, M. De Jesus

Simulations of neutron background from rock for underground experiments are presented. Neutron propagation through two types of rock, lead and hydrocarbon material is discussed. The results show a reasonably good agreement between GEANT4, MCNPX and GEANT3 in transporting low-energy neutrons.

E. Perez

An overview of experimental results on searches for new phenomena at HERA is presented. The complementarity with searches performed at other experiments is discussed and the prospects for a discovery, using the full HERA data to be delivered until mid-2007, are presented.

Joe Henson

A criticism sometimes made of the causal set quantum gravity program is that there is no practical scheme for identifying manifoldlike causal sets and finding embeddings of them into manifolds. A computational method for constructing an approximate embedding of a small manifoldlike causal set into Minkowski space (or any spacetime that is approximately flat

V. N. Pervushin, V. A. Zinchuk

Quantum Cosmology and Gravity are formulated here as the primary and secondary quantizations of the energy constraints by analogy with the historical formulation of quantum field theory. New fact is that both the Universe and its matter are created from stable vacuum obtained by the Bogoliubov-type transformation just as it is in the theory of quantum superf

Paul S. Wesson

Higher-dimensional theories of the kind which may unify gravitation with particle physics can lead to significant modifications of general relativity. In five dimensions, the vacuum becomes non-standard, and the Weak Equivalence Principle becomes a geometrical symmetry which can be broken, perhaps at a level detectable by new tests in space.

Benjamin Gaidioz, Birger Koblitz, Nuno Santos

We explore the feasibility of implementing a reliable, high performance, distributed storage system on a commodity computing cluster. Files are distributed across storage nodes using erasure coding with small Low-Density Parity-Check (LDPC) codes which provide high reliability while keeping the storage and performance overhead small. We present performance m

B. S. Shajee Mohan, V. K. Govindan

Compression algorithms reduce the redundancy in data representation to decrease the storage required for that data. Data compression offers an attractive approach to reducing communication costs by using available bandwidth effectively. Over the last decade there has been an unprecedented explosion in the amount of digital data transmitted via the Internet,

K. S. Ooi

We describe a novel way in which students can learn the cipher systems without much supervision. In this work we focus on learning symmetric ciphers by altering them using the agile development approach. Two agile approaches the eXtreme Programming (XP) and the closely related Test-Driven Development (TDD) are mentioned or discussed. To facilitate this devel

Anjana Bagga, Pekka Pietilainen, Tapash Chakraborty

The effects of spin-orbit (SO) coupling arising from the confinement potential in single and two vertically-coupled quantum dots have been investigated. Our work indicates that a dot containing a single electron shows the lifting of the degeneracy of dipole-allowed transitions at B=0 due to the SO coupling which disappears for a dot containing two electrons.

Guenter Schneider, Peter Schmitteckert

A new method to perform linear and finite bias conductance calculations in one dimensional systems based on the calculation of real time evolution within the Density Matrix Renormalization Group (DMRG) is presented. We consider a system of spinless fermions consisting of an extended interacting nanostructure attached to non-interacting leads. Results for the

C. M. Roland, K. J. McGrath, R. Casalini

The role of jamming (steric constraints) and its relationship to the available volume is addressed by examining the effect that certain modifications of a glass-former have on the ratio of its isochoric and isobaric activation enthalpies. This ratio reflects the relative contribution of volume (density) and temperature (thermal energy) to the temperature-dep

David Ford

The wavefunction of a single spin system in a prepared initial state evolves to equilibrium with a heat bath. The average spin $$q(t) = p_{\uparrow}(t) - p_{\downarrow}(t)$$ exhibits a characteristic time for this evolution. With the proper choice of spin flip rates, a dynamical Ising model (Glauber) can be constructed with the same characteristic time for t

Mucio A. Continentino

We study phase transitions in heavy fermion systems due to spin-wave instabilities. One motivation is to determine the changes in the spin-wave parameters of a magnetically ordered heavy fermion system as it approaches a quantum critical point (QCP) by applying pressure. The other more actual is to provide an alternative approach, based on spin-wave instabil

Georg Albert, Marco Maccarini, Michael Himmelhaus

Thin films of gold were deposited on single crystalline CaF2 substrates of (100) and (111) orientation by thermal evaporation. The resulting film structure was analyzed by means of atomic force microscopy in dependence of substrate temperature and deposition thickness. A marked substrate dependency was found. On CaF2 (100), extended and flat plateaus with di

M. K. Kneip, D. R. Yakovlev, M. Bayer, T. Slobodskyy

We show that the magnetization dynamics in diluted magnetic semiconductors can be controlled separately from the static magnetization by means of an electric field. The spin-lattice relaxation (SLR) time of magnetic Mn2+ ions was tuned by two orders of magnitude by a gate voltage applied to n-type modulation-doped (Zn,Mn)Se/(Zn,Be)Se quantum wells. The effec

A. Greco, R. Zeyher

The excitation spectrum of the t-J model is studied on a square lattice in the large $N$ limit in a doping range where a $d$-$density$-$wave$ (DDW) forms below a transition temperature $T^\star$. Characteristic features of the DDW ground state are circulating currents which fluctuate above and condense into a staggered flux state below $T^\star$ and density

Andrzej M. Oles, Giniyat Khaliullin, Peter Horsch, Louis Felix Feiner

The temperature dependence and anisotropy of optical spectral weights associated with different multiplet transitions is determined by the spin and orbital correlations. To provide a systematic basis to exploit this close relationship between magnetism and optical spectra, we present and analyze the spin-orbital superexchange models for a series of represent

Kamil Walczak

The rate-equation approach is used to describe sequential tunneling through a molecular junction in the Coulomb blockade regime. Such device is composed of molecular quantum dot (with discrete energy levels) coupled with two metallic electrodes via potential barriers. Based on this model, we calculate nonlinear transport characteristics (conductance-voltage

G. Catelani

We consider the tunneling Density of States (DoS) of superconducting films driven to the paramagnetic phase by the Zeeman splitting. We show that there is minimum in the DoS whose position depends on the orientation of the applied field. This dependence, not predicted by previous theoretical calculations, is in agreement with a recent experiment.

R. Casalini, S. Capaccioli, C. M. Roland

Relaxation times for different temperatures, T, and specific volumes, V, collapse to a master curve versus TV^g, with g a material constant. The isochoric fragility, m_V, is also a material constant, inversely correlated with g. From these we obtain a 3-parameter function, which fits accurately relaxation times of several glass-formers over the supercooled r

L. Chioncel, E. Arrigoni, M. I. Katsnelson, A. I. Lichtenstein

Electron-electron correlations affect the band gap of half-metallic ferromagnets by introducing non-quasiparticle states just above the Fermi level. In contrast to the spin-orbit coupling, a large asymmetric non-quasiparticle spectral weight is present in the minority-spin channel, leading to a peculiar finite-temperature spin depolarization effects. Using r

X. S. Wu, P. W. Adams, G. Catelani

We report a detailed study of the pairing resonance via tunneling density of states in ultra-thin superconducting Al films in supercritical magnetic fields. Particular emphasis is placed on effects of the perpendicular component of the magnetic field on the resonance energy and magnitude. Though the resonance is broadened and attenuated by $H_\bot$ as expect

G. Aprea, C. Di Castro, M. Grilli, J. Lorenzana

We investigate the interplay between the electron-electron and the electron-phonon interaction in the Hubbard-Holstein model. We implement the flow-equation method to investigate within this model the effect of correlation on the electron-phonon effective coupling and, conversely, the effect of phonons in the effective electron-electron interaction. Using th

J. Klein Wolterink, G. T. Barkema, Sanjay Puri

We present experimental results for spinodal decomposition in polymer mixtures of gelatin and dextran. The domain growth law is found to be consistent with t^1/4-growth over extended time-regimes. Similar results are obtained from lattice simulations of a polymer mixture. This slow growth arises due to the suppression of the bulk mobility of polymers. In tha

Nicola M. Pugno

Spiders suggest us that producing high strength over density ratio invisible cables could be of great importance. In this letter we show that such invisible cables could in principle be built, thanks to carbon nanotube bundles. Theoretical strength of about 10MPa, Young modulus of about 0.1GPa and density of 0.1Kg per cubic meter are estimated.

Nicola M. Pugno

In this letter we derive a universal law for nanoindentation, considering different sizes and shapes of the indenter. The law matches as limit cases all the well-known hardness scaling laws proposed in the literature. But our finding can also explain their deviations experimentally observed at the nanoscale. An even more general scaling law is then formulate

Matthias Braun, Jürgen König, Jan Martinek

We study frequency-dependent current noise through a single-level quantum dot connected to ferromagnetic leads with non-collinear magnetization. We propose to use the frequency-dependent Fano factor as a tool to detect single-spin dynamics in the quantum dot. Spin precession due to an external magnetic and/or a many-body exchange field affects the Fano facto

N. Binggeli, M. Altarelli

The origin of the correlation between surface reactivity and quantum-size effects, observed in recent experiments on the oxidation of ultrathin magnesium films, is addressed by means of ab-initio calculations and model predictions. We show that the decay length in vacuum of the electronic local density of states at the Fermi energy exhibits systematic oscill

Andrea Antoniazzi, Yves Elskens, Duccio Fanelli, Stefano Ruffo

A reduced Hamiltonian formulation to reproduce the saturated regime of a single pass free electron laser, around perfect tuning, is here discussed. Asymptotically, $N\_m$ particles are found to organize in a dense cluster, that evolves as an individual massive unit. The remaining particles fill the surrounding uniform sea, spanning a finite portion of phase

A. Thilagam, M. A. Lohe

We investigate the spin dynamics of excitons interacting with acoustic phonons in quantum wells, quantum wires and quantum disks by employing a multiband model based on the $4\times4$ Luttinger Hamiltonian. We also use the Bir-Pikus Hamiltonian to model the coupling of excitons to both longitudinal acoustic phonons and transverse acoustic phonons, thereby pr

V. P. S. Awana, M. Isobe, K. P. Singh, Md. Shahabuddin

Polycrystalline MgB2 samples with 0, 2, 4 and 6 percent added nano-Co3O4 being synthesized by vacuum (10-5 Torr) annealing at 750 0C for three hours each are found to be nearly single phase with presence of only a small quantity of Mg/MgO in pristine sample and in addition the Co2O3 in doped compounds. All the samples exhibited clear and sharp diamagnetic tr

Hideo Hasegawa

We have studied the synchronization in finite $N$-unit FitzHugh-Nagumo neuron ensembles subjected to additive and multiplicative noises, by using the augmented moment method (AMM) which is reformulated with the use of the Fokker-Planck equation. It has been shown that for diffusive couplings, the synchronization may be enhanced by multiplicative noises while

Zi-Gang Huang, Xin-Jian Xu, Zhi-Xi Wu, Ying-Hai Wang

We carry out comparative studies of random walks on deterministic Apollonian networks (DANs) and random Apollonian networks (RANs). We perform computer simulations for the mean first passage time, the average return time, the mean-square displacement, and the network coverage for unrestricted random walk. The diffusions both on DANs and RANs are proved to be

Zhi-Feng Huang, Jorge Vinals

In order to address the selection mechanism that is responsible for the unique lamellar orientation observed in block copolymers under oscillatory shears, we use a constitutive law for the dissipative part of the stress tensor that respects the uniaxial symmetry of a lamellar phase. An interface separating two domains oriented parallel and perpendicular to t

Emir Haleva, Haim Diamant

We revisit the problem of a two-dimensional polymer ring subject to an inflating pressure differential. The ring is modeled as a freely jointed closed chain of N monomers. Using a Flory argument, mean-field calculation and Monte Carlo simulations, we show that at a critical pressure, $p_c \sim N^{-1}$, the ring undergoes a second-order phase transition from

N. Kim, H. Kim, J. W. Kim, S. J. Lee

We propose a ferromagnetic/ferroelectric hybrid double quantum well structure, and present an investigation of the Curie temperature (Tc) modulation in this quantum structure. The combined effects of applied electric fields and spontaneous electric polarization are considered for a system that consists of a Mn δ-doped well, a barrier, and a p-type ferroelect

Guy Hed, S. A. Safran

The concept of network immunity, i.e., the robustness of the network connectivity after a random deletion of edges or vertices, has been investigated in biological or communication networks. We apply this concept to a self-assembling, physical network of microemulsion droplets connected by telechelic polymers, where more than one polymer can connect a pair o

S. N. Coppersmith

Satisfiability is a classic problem in computational complexity theory, in which one wishes to determine whether an assignment of values to a collection of Boolean variables exists in which all of a collection of clauses composed of logical OR's of these variables is true. Here, a renormalization group transformation is constructed and used to relate the

T. Verkholyak, A. Honecker, W. Brenig

The Jordan-Wigner transformation is applied to study the ground state properties and dimerization transition in the $J_1-J_2$ $XXZ$ chain. We consider different solutions of the mean-field approximation for the transformed Hamiltonian. Ground state energy and the static structure factor are compared with complementary exact diagonalization and good agreement

Katharina Lodders, Bruce Fegley,

"Brown dwarfs" is the collective name for objects more massive than giant planets such as Jupiter but less massive than M dwarf stars. This review gives a brief description of the classification and chemistry of low mass dwarfs. The current spectral classification of stars includes L and T dwarfs that encompass the coolest known stars and substellar

O. M. Blaes, S. W. Davis, S. Hirose, J. H. Krolik

Stellar atmosphere models of ionized accretion disks have generally neglected the contribution of magnetic fields to the vertical hydrostatic support, although magnetic fields are widely believed to play a critical role in the transport of angular momentum. Simulations of magnetorotational turbulence in a vertically stratified shearing box geometry show that

O. M. Blaes, P. Arras, P. C. Fragile

Accretion flows with pressure gradients permit the existence of standing waves which may be responsible for observed quasi-periodic oscillations (QPO's) in X-ray binaries. We present a comprehensive treatment of the linear modes of a hydrodynamic, non-self-gravitating, polytropic slender torus, with arbitrary specific angular momentum distribution, orbit

R. P. Kraft, C. Jones, P. E. J. Nulsen, M. J. Hardcastle

We present results from a short {\em Chandra}/ACIS-S observation of NGC 7618, the dominant central galaxy of a nearby ($z$=0.017309, d=74.1 Mpc) group. We detect a sharp surface brightness discontinuity 14.4 kpc N of the nucleus subtending an angle of 130$^\circ$ with an X-ray tail extending $\sim$ 70 kpc in the opposite direction. The temperature of the gas

Asantha Cooray, Robert R. Caldwell

We investigate the extent to which correlated distortions of the luminosity distance-redshift relation due to large-scale bulk flows limit the precision with which cosmological parameters can be measured. In particular, peculiar velocities of type 1a supernovae at low redshifts may prevent a sufficient calibration of the Hubble diagram necessary to measure t

O. Daigle, C. Carignan, P. Amram, O. Hernandez

This is the first part of an Halpha kinematics follow-up survey of the SINGS sample. The data for 28 galaxies are presented. The observations were done on three different telescopes with FaNTOmM, an integral field photon counting spectrometer, installed in the respective focal reducer of each telescope. The data reduction was done through a newly built pipel

G. Worseck, L. Wisotzki

We report the discovery of the faint (V=21.7) quasar QSO03027-0010 at z=2.808 in the vicinity of Q0302-003, one of the few quasars observed with STIS to study intergalactic HeII absorption. Together with another newly discovered QSO at z=2.29, there are now 6 QSOs known near the line of sight towards Q0302-003, of which 4 are located within the redshift regi

M. Lemoine-Goumard, B. Degrange, M. Tluczykont

A simple 3D-reconstruction method for gamma-ray induced air showers is presented, which takes full advantage of the assets of a system of Atmospheric Cherenkov Telescopes combining stereoscopy and fine-grain imaging like the High Energy Stereoscopic System (H.E.S.S.). The rich information collected by the cameras allows to select electromagnetic showers on t

E. Pompei, R. R. de Carvalho, A. Iovino

This paper presents the results of a pilot redshift survey of 18 candidate compact groups from the distant DPOSS survey that extends the available surveys of compact groups of galaxies to z ~0.2 in redshift, mainly Hickson Compact Groups and Southern Compact Groups. The goal of our survey was to confirm group membership via redshift information and to measur

P. Saha, F. Courbin, D. Sluse, S. Dye

Aims: To predict time delays for a sample of gravitationally lensed quasars and to evaluate the accuracy that can be realistically achieved on the value of H_0. Methods: We consider 14 lensed quasars that are candidates for time-delay monitoring and model them in detail using pixelized lens models. For each system, we provide a mass map, arrival-time surface

V. M. Bakulev

The new approach of the regular spacing of planetary orbits and planet mass distribution in the Solar system is considered. The relative planetary distances will be represented as the inverse composite probabilities of two discrete distributions with one fitted parameter. Conceivable physical interpretation of these distributions and fitted parameter will be

Joanna M. Rankin, Cameron Rodriguez, Geoffrey A. E. Wright

A new single pulse behaviour has been identified in two pulsars, B0919+06 and B1859+07. Normally both starts emit bright subpulses in a region near the trailing edge of heir profile. However, occasionally these stars exhibit "events" wherein the emission longitude gradually decreases by about their profile width, remains in this position for typicall

J. Bergeat, L. Chevallier

(Shortened version): The mass loss rates, expansion velocities and dust-to-gas density ratios from millimetric observations of 119 carbon-rich giants are compared, as functions of stellar parameters, to the predictions of recent hydrodynamical models. Distances and luminosities previously estimated from HIPPARCOS data, masses from pulsations and C/O abundanc

Miroslav Pardy

We consider the Foucault pendulum, isosceles triangle pendulum and the general triangle pendulum rotating on the Earth. As an analogue, planet orbiting in the rotating galaxy is considered as the giant galactical gyroscope. The Lorentz and the Bargman-Michel-Telegdi equations are generalized for the rotating system. These equations are inevitable for LHC whe

Michael Truss, Chris Done

The galactic microquasar GRS 1915+105 has been in a continuous state of outburst since 1992, over 20 times longer than any other black hole X-ray transient. Assuming that the outburst is powered via accretion of an irradiated gaseous disc, we calculate how the predicted outburst duration varies according to the efficiency of the self-irradiation mechanism. A

I. Hunter, J. V. Smoker, F. P. Keenan, C. Ledoux

We present an analysis of interstellar Na I (lambda=3302.37Å, 3302.98Å), Ti II (lambda=3383.76Å) and Ca II K (lambda=3933.66Å) absorption features for 74 sightlines towards O- and B-type stars in the Galactic disc. The data were obtained from the UVES Paranal Observatory Project, at a spectral resolution of 3.75km/s and with mean signal to noise ratios per p

K. E. Gabanyi, T. P. Krichbaum, S. Britzen, U. Bach

The quasar B2005+403 located behind the Cygnus region, is a suitable object for studying the interplay between propagation effects, which are extrinsic to the source and source intrinsic variability. On the basis of VLBI experiments performed at 1.6, 5, 8, 15, 22, and 43GHz between 1992-2003 and parallel multi-frequency monitoring of the total flux density,

P. F. Roche, C. Packham, C. M. Telesco, J. T. Radomski

High spatial resolution spectroscopy at 8-13microns with T-ReCS on Gemini-S has revealed striking variations in the mid-infrared emission and absorption in the nucleus of the Circinus galaxy on sub-arcsecond scales. The core of Circinus is compact and obscured by a substantial column of cool silicate dust. Weak extended emission to the east and west coincide

I. Montilla, J. Sellos, S. F. Pereira, J. J. M. Braat

Wide field interferometry has become a subject of increasing interest in the recent years. New methods have been suggested in order to avoid the drawbacks of the standard wide-field method (homothetic mapping) which is not applicable when the aperture is highly diluted; for this reason imaging with non-homothetic arrays is being extensively studied [1], [2].

Priscilla C. Frisch, Jonathan D. Slavin

The galactic environment of the Sun varies over short timescales as the Sun and interstellar clouds travel through space. Small variations in the dynamics, ionization, density, and magnetic field strength of the interstellar medium (ISM) surrounding the Sun yield pronounced changes in the heliosphere. We discuss essential information required to understand s

J. L. Han, R. N. Manchester, A. G. Lyne, G. J. Qiao

The large-scale magnetic field of our Galaxy can be probed in three dimensions using Faraday rotation of pulsar signals. We report on the determination of 223 rotation measures from polarization observations of relatively distant southern pulsars made using the Parkes radio telescope. Combined with previously published observations these data give clear evid

Priscilla C. Frisch

Speculations that encounters with interstellar clouds modify the terrestrial climate have appeared in the scientific literature for over 85 years. This article introduces a series of articles that seek to give substance to these speculations by examining the exact mechanisms that link the pressure and composition of the interstellar medium surrounding the Su

Eric V. Linder

Baryon acoustic oscillations, measured through the patterned distribution of galaxies or other baryon tracing objects on very large (100 Mpc) scales, offer a possible geometric probe of cosmological distances. Pluses and minuses in this approach's leverage for understanding dark energy are discussed, as are systematic uncertainties requiring further inve

A. V. Belitsky, A. S. Gorsky, G. P. Korchemsky

We study anomalous dimensions of (super)conformal Wilson operators at weak and strong coupling making use of the integrability symmetry on both sides of the gauge/string correspondence and elucidate the origin of their single-logarithmic behavior for long operators/strings in the limit of large Lorentz spin. On the gauge theory side, we apply the method of t

Andreas A. Berlind, Joshua A. Frieman, David H. Weinberg, Michael R. Blanton

We identify galaxy groups and clusters in volume-limited samples of the SDSS redshift survey, using a redshift-space friends-of-friends algorithm. We optimize the friends-of-friends linking lengths to recover galaxy systems that occupy the same dark matter halos, using a set of mock catalogs created by populating halos of N-body simulations with galaxies. Ex

Shamit Kachru, John McGreevy, Peter Svrcek

In string compactification on a manifold X, in addition to the string scale and the normal scales of low-energy particle physics, there is a Kaluza-Klein scale 1/R associated with the size of X. We present an argument that generic string models with low-energy supersymmetry have, after moduli stabilization, bulk fields with masses which are parametrically li

G. Khoury, H. S. Eisenberg, E. J. S. Fonseca, D. Bouwmeester

We use a photon-number resolving detector to monitor the photon number distribution of the output of an interferometer, as a function of phase delay. As inputs we use coherent states with mean photon number up to seven. The postselection of a specific Fock (photon-number) state effectively induces high-order optical non-linearities. Following a scheme by Ben

Yoshifumi Hyakutake, Sachiko Ogushi

In this paper we derive higher derivative corrections to the eleven dimensional supergravity by applying the Noether method with respect to the N=1 local supersymmetry. An ansatz for the higher derivative effective action, which includes quartic terms of the Riemann tensor, is parametrized by 132 parameters. Then we show that by the requirement of the local

O. A. Gelfond, E. D. Skvortsov, M. A. Vasiliev

Using unfolded formulation of free equations for massless fields of all spins we obtain explicit form of higher-spin conformal conserved charges bilinear in 4d massless fields of arbitrary spins.

Edward Lyman, Daniel M. Zuckerman

Assessing the convergence of a biomolecular simulation is an essential part of any computational investigation. This is because many important quantities (e.g., free energy differences) depend on the relative populations of different conformers; insufficient convergence translates into systematic errors. Here we present a simple method to self-consistently a

Heng-Yu Chen, Keisuke Okamura

We consider the correspondence between the spinning string solutions in Lunin-Maldacena background and the single trace operators in the Leigh-Strassler deformation of N=4 SYM. By imposing an appropriate rotating string ansätz on the Landau-Lifshitz reduced sigma model in the deformed SU(2) sector, we find two types of `elliptic' solutions with two spins

Sarah E. Shandera, S. -H. Henry Tye

Linking the slow-roll scenario and the Dirac-Born-Infeld scenario of ultra-relativistic roll (where, thanks to the warp factor, the inflaton moves slowly even with an ultra-relativistic Lorentz factor), we find that the KKLMMT D3/anti-D3 brane inflation is robust, that is, enough e-folds of inflation is quite generic in the parameter space of the model. We s

Marek Golasinski, Daciberg Gonçalves, Peter Wong

In this paper, we define equivariant evaluation subgroups of the higher Rhodes groups and study their relations with Gottlieb-Fox groups.

Arkady Berenstein, David Kazhdan

For each reductive algebraic group G we introduce and study unipotent bicrystals which serve as a regular version of birational geometric and unipotent crystals introduced earlier by the authors. The framework of unipotent bicrystals allows, on the one hand, to study systematically such varieties as Bruhat cells in G and their convolution products and, on th

Marek Golasinski, Daciberg Gonçalves, Peter Wong

In 1945, R. Fox introduced the so-called Fox torus homotopy groups in which the usual homotopy groups are embedded and their Whitehead products are expressed as commutators. A modern treatment of Fox torus homotopy groups and their generalization has been given and studied. In this note, we further explore these groups and their properties. We discuss co-mul

Frans R. Klinkhamer

A model is presented to illustrate that vacuum neutrino oscillations can be essentially T and CP invariant up to a certain energy but strongly T and CP noninvariant at much higher energies. Detailed model results for the vacuum probabilities P(nu_mu to nu_e) and P(nu_e to nu_mu) are given, which may be relevant to proposed long-baseline neutrino-oscillation

Simone Paziani, Saverio Moroni, Paola Gori-Giorgi, Giovanni B. Bachelet

Based on exact limits and quantum Monte Carlo simulations, we obtain, at any density and spin polarization, an accurate estimate for the energy of a modified homogeneous electron gas where electrons repel each other only with a long-range coulombic tail. This allows us to construct an analytic local-spin-density exchange-correlation functional appropriate to

Richard Steiner

The orientals or oriented simplexes are a family of strict omega-categories constructed by Ross Street. We show that the category of orientals is isomorphic to a subcategory of the category of chain complexes. This leads to a very simple combinatorial description of the morphisms between orientals. We also show that the category of orientals is the closure o

R. P. Andrews, N. Dorey

We demonstrate a classical equivalence between the large-N limit of the Higgsed N=1* SUSY U(N) Yang-Mills theory and the Maldacena-Nunez twisted compactification of a six dimensional gauge theory on a two-sphere. A direct comparison of the actions and spectra of the two theories reveals them to be identical. We also propose a gauge theory limit which should

Z. Bajnok

The spectrum of integrable spin chains are shown to be independent of the ordering of their spins. As an application we introduce defects (local spin inhomogeneities in homogenous chains) in two-boundary spin systems and, by changing their locations, we show the spectral equivalence of different boundary conditions. In particular we relate certain nondiagona

Y. Krivolapov, A. Mann, Joseph L. Birman

A U(3) model proposed by Iachello for superconductivity in cuprate materials is analyzed. The model consists of s and d pairs (approximated as bosons) in a two-dimensional Fermi system with a surface. The transition occurs between a phase in which the system is a condensate of one of the bosons, and a phase which is a mixture of two types of bosons. In the c

S. K. Singh, M. Sajjad Athar, Shakeb Ahmad

The coherent pion production induced by neutrinos in nuclei is studied using a delta hole model in local density approximation taking into account the renormalization of $Δ$ properties in a nuclear medium. The pion absorption effects have been included in an eikonal approximation. These effects give a large reduction in the total cross section. The numerical

Cédric Bonnafé, Raphaël Rouquier

Let $G$ be a connected reductive algebraic group defined over an algebraic closure of a finite field and let $F : G \to G$ be an endomorphism such that $F^d$ is a Frobenius endomorphism for some $d \geq 1$. Let $P$ be a parabolic subgroup of $G$ admitting an $F$-stable Levi subgroup. We prove that the Deligne-Lusztig variety $\{gP | g^{-1}F(g)\in P\cdot F(P)

Anton Cox, Maud De Visscher, Paul Martin

We determine the blocks of the Brauer algebra in characteristic zero. We also give information on the submodule structure of standard modules for this algebra.

Mildred Hager, Johannes Sjoestrand

We consider quite general $h$-pseudodifferential operators on $R^n$ with small random perturbations and show that in the limit of small $h$ the eigenvalues are distributed according to a Weyl law with a probabality that tends to 1. The first author has previously obtained a similar result in dimension 1. Our class of perturbations is different.