September 2007 arXiv papers — page 40

Adam N. Letchford, Hanna Seitz, Dirk Oliver Theis

We examine the metrics that arise when a finite set of points is embedded in the real line, in such a way that the distance between each pair of points is at least 1. These metrics are closely related to some other known metrics in the literature, and also to a class of combinatorial optimization problems known as graph layout problems. We prove several resu

Mathieu Hoyrup, Cristobal Rojas

In this paper we investigate algorithmic randomness on more general spaces than the Cantor space, namely computable metric spaces. To do this, we first develop a unified framework allowing computations with probability measures. We show that any computable metric space with a computable probability measure is isomorphic to the Cantor space in a computable an

Joshua Jay Herman

Major mistakes do not read

Lie-Wen Chen, Che Ming Ko, Bao-An Li

Using various relativistic mean-field models, including the nonlinear ones with meson field self-interactions, those with density-dependent meson-nucleon couplings, and the point-coupling models without meson fields, we have studied the isospin-dependent bulk and single-particle properties of asymmetric nuclear matter. In particular, we have determined the d

S. Capozziello, A. Stabile, A. Troisi

Spherical symmetry in $f(R)$ gravity is discussed in details considering also the relations with the weak field limit. Exact solutions are obtained for constant Ricci curvature scalar and for Ricci scalar depending on the radial coordinate. In particular, we discuss how to obtain results which can be consistently compared with General Relativity giving the w

Venkatesan Guruswami, James R. Lee, Alexander Razborov

We give an explicit (in particular, deterministic polynomial time) construction of subspaces X of R^N of dimension (1-o(1))N such that for every element x in X, |x|_1 and N^{1/2} |x|_2 are equivalent up to a factor of (log N)^{log log log N}. If we are allowed to use N^{o(1)} random bits, this factor can be improved to poly(log N). Our construction makes use

V. G. Gurzadyan, A. A. Starobinsky, A. L. Kashin, H. Khachatryan

We study inhomogeneities in the distribution of the excursion sets in the Cosmic Microwave Background (CMB) temperature maps obtained by the three years survey of the Wilkinson Microwave Anisotropy Probe (WMAP). At temperature thresholds |T|<90 μK, the distributions of the excursion sets with over 200 pixels are concentrated in two regions, nearly at the ant

Vladimir Shevelev

We give two simple algorithms for the evaluation of difference between the numbers of multiples of 3 with even and odd binary digit sums in interval [0,x), and give an elementary proof of Coquet&#39;s sharp estimates for it.

J. Martin, Antonio F. Rañada, A. Tiemblo

A general framework for the solutions of the constraints of pure gravity is constructed. It provides with well defined mathematical criteria to classify their solutions in four classes. Complete families of solutions are obtained in some cases. A starting point for the systematic study of the solutions of Einstein gravity is suggested.

Raika Dehy, Bernhard Keller

Given a triangulated 2-Calabi-Yau category C and a cluster-tilting subcategory T, the index of an object X of C is a certain element of the Grothendieck group of the additive category T. In this note, we show that a rigid object of C is determined by its index, that the indices of the indecomposables of a cluster-tilting subcategory T&#39; form a basis of th

Jin-Wu Jiang, Hui Tang, Bing-Shen Wang, Zhao-Bin Su

The symmetry group analysis is applied to classify the phonon modes of $N$-stacked graphene layers (NSGL&#39;s) with AB- and AA-stacking, particularly their infra-red and Raman properties. The dispersions of various phonon modes are calculated in a multi-layer vibrational model, which is generalized from the lattice vibrational potentials of graphene to incl

Matthias C. Lüffe, Jens Koch, Felix von Oppen

Current-driven vibrational non-equilibrium induces vibrational sidebands in single-molecule transistors which arise from tunneling processes accompanied by absorption of vibrational quanta. Unlike conventional sidebands, these absorption sidebands occur in a regime where the current is nominally Coulomb blockaded. Here, we develop a detailed and analytical t

M. L. McClure, Charles Hellaby

The ultimate application of Einstein&#39;s field equations is to empirically determine the geometry of the Universe from its matter content, rather than simply assuming the Universe can be represented by a homogeneous model on all scales. Choosing an LTB model as the most convenient inhomogeneous model for the early stages of development, a data reduction pr

Uma N. Iyer, Timothy C. McCune

Withdrawn on account of a crucial error in the main theorem

Nikolai Dokuchaev

We suggest a modification of the estimate for weighted Sobolev norms of solutions of parabolic equations such that the matrix of the higher order coefficients is included into the weight for the gradient. More precisely, we found the upper limit estimate that can be achieved by variations of the zero order coefficient. As an example of applications, an asymp

Paulo Murilo Castro de Oliveira, Dietrich Stauffer, Soeren Wichmann, Suzana Moss de Oliveira

This paper presents Monte Carlo simulations of language populations and the development of language families, showing how a simple model can lead to distributions similar to the ones observed empirically. The model used combines features of two models used in earlier work by phycisists for the simulation of competition among languages: the &#34;Viviane&#34;

A. Beifiori, E. M. Corsini, E. Dalla Bonta&#39;, A. Pizzella

The growth of supermassive black holes (SMBHs) appears to be closely linked with the formation of spheroids. There is a pressing need to acquire better statistics on SMBH masses, since the existing samples are preferentially weighted toward early-type galaxies with very massive SMBHs. With this motivation we started a project aimed at measuring upper limits

Margherita Barile

Using aritmethic conditions on affine semigroups we prove that for a simplicial toric variety of codimension 2 the property of being a set-theoretic complete intersection on binomials in characteristic $p$ holds either for all primes $p$, or for no prime $p$, or for exactly one prime $p$.

Chris Pedder, Julian Sonner, David Tong

We explore the geometric phase in N=(2,2) supersymmetric quantum mechanics. The Witten index ensures the existence of degenerate ground states, resulting in a non-Abelian Berry connection. We exhibit a non-renormalization theorem which prohibits the connection from receiving perturbative corrections. However, we show that it does receive corrections from BPS

Ekaterina V. Kutafina

We consider the hyperbolic generalization of Burgers equation with polynomial source term. The transformation of auto-Bäcklund type was found. Application of the results is shown in the examples, where the pair of two stationary solutions produces kink and bi-kink solutions.

A. J. Bennett, D. G. Gevaux, Z. L. Yuan, A. J. Shields

We report an experiment in which two-photon interference occurs between degenerate single photons that never meet. The two photons travel in opposite directions through our fibre-optic interferometer and interference occurs when the photons reach two different, spatially separated, 2-by-2 couplers at the same time. We show that this experiment is analogous t

David L. Wiltshire

The exact solution of a two-scale Buchert average of the Einstein equations is derived for an inhomogeneous universe which represents a close approximation to the observed universe. The two scales represent voids, and the bubble walls surrounding them within which clusters of galaxies are located. As described elsewhere [gr-qc/0702082], apparent cosmic accel

Jian-Zu Zhang

The induced fractional zero-point canonical angular momentum on charged particles by the Aharonov - Bohm (AB) vector potential is realized via modified combined traps. It explores new features for this type of quantum effects: In a limit of vanishing mechanical kinetic energy the AB vector potential alone cannot induce a fractional zero-point canonical angul

Jean-Francois Grosjean, Julien Roth

In this paper we give pinching theorems for the first nonzero eigenvalue of the Laplacian on the compact hypersurfaces of ambient spaces with bounded sectional curvature. As application we deduce rigidity results for stable constant mean curvature hypersurfaces $M$ of these spaces $N$. Indeed, we prove that if $M$ is included in a ball of radius small enough

S. Tassy, N. Nemitz, F. Baumer, C. Höhl

We have experimentally realized a hybrid trap for ultracold paramagnetic rubidium and diamagnetic ytterbium atoms by combining a bichromatic optical dipole trap for ytterbium with a Ioffe-Pritchard-type magnetic trap for rubidium. In this hybrid trap, sympathetic cooling of five different ytterbium isotopes through elastic collisions with rubidium was achiev

Tobias Kaestner, Georg Bergner, Sebastian Uhlmann, Andreas Wipf

We study and simulate N=2 supersymmetric Wess-Zumino models in one and two dimensions. For any choice of the lattice derivative, the theories can be made manifestly supersymmetric by adding appropriate improvement terms corresponding to discretizations of surface integrals. In particular, we check that fermionic and bosonic masses coincide and the unbroken W

A. Perali, P. Pieri, G. C. Strinati

The radio-frequency spectra of ultracold Fermi atoms are calculated by including final-state interactions affecting the excited level of the transition, and compared with the experimental data. A competition is revealed between pairing-gap effects which tend to push the oscillator strength toward high frequencies away from threshold, and final-state effects

J. Lages, A. Berard, H. Mohrbach, Y. Grandati

Dyson published in 1990 a proof due to Feynman of the Maxwell equations. This proof is based on the assumption of simple commutation relations between position and velocity. We first study a nonrelativistic particle using Feynman formalism. We show that Poincaré&#39;s magnetic angular momentum and Dirac magnetic monopole are the direct consequences of the st

Jesper Lykke Jacobsen, Hubert Saleur

We discuss in this paper combinatorial aspects of boundary loop models, that is models of self-avoiding loops on a strip where loops get different weights depending on whether they touch the left, the right, both or no boundary. These models are described algebraically by a generalization of the Temperley-Lieb algebra, dubbed the two-boundary TL algebra. We

Y. C. Lin, K. Yun, T. M. Hong

The Hele-Shaw experiment is performed with a circular invasion to study the scaling and dynamic behavior of the interface. We did not find any universal power law. The time exponent varies with the range of scale, as has been reported in the literature but not captured by existing models. We ascribe this distinct difference from the planar injection to the f

Xavier Bardina, Ivan Nourdin, Carles Rovira, Samy Tindel

In this note, a diffusion approximation result is shown for stochastic differential equations driven by a (Liouville) fractional Brownian motion B with Hurst parameter H in (1/3,1/2). More precisely, we resort to the Kac-Stroock type approximation using a Poisson process studied in Bardina, Jolis and Tudor (2003) and Delgado and Jolis (2000), and our method

Francois Dahmani, Koji Fujiwara

We establish that, given $Σ$ a compact orientable surface, and $G$ a finitely presented one-ended group, the set of copies of $G$ in the mapping class group $\mathcal{MCG}(Σ)$ consisting of only pseudo-anosov elements except identity, is finite up to conjugacy. This relies on a result of Bowditch on the same problem for images of surfaces groups. He asked us

Taesoo Song, Yongjae Park, Su Houng Lee, Cheuk-Yin Wong

The velocity dependence of the thermal width of heavy quarkonia traveling with respect to the quark gluon plasma is calculated up to the NLO in perturbative QCD. At the LO, the width decreases with increasing speed, whereas at the NLO it increases with a magnitude approximately proportional to the expectation value of the relative velocity between the quarko

Masaki Nakagawa

We describe the integral cohomology rings of the flag manifolds of types B_n, D_n, G_2 and F_4 in terms of their Schubert classes. The main tool is the divided difference operators of Bernstein-Gelfand-Gelfand and Demazure. As an application, we compute the Chow rings of the corresponding complex algebraic groups, recovering thereby the results of R. Marlin.

Yuri A. Rylov

Not any geometry can be axiomatized. The paradoxical Godel&#39;s theorem starts from the supposition that any geometry can be axiomatized and goes to the result, that not any geometry can be axiomatized. One considers example of two close geometries (Riemannian geometry and $σ$-Riemannian one), which are constructed by different methods and distinguish in so

You-Gang Feng

In this paper we lay special stress on analyzing the topological properties of the lattice systems and try to ovoid the conventional ways to calculate the critical points. Only those clusters with finite sizes can execute the self similar transformations of infinite hierarchies. Each ordered cluster has fractal dimension, their minimum relates to the edge fi

David H. Adams, Weonjong Lee

For logarithmically divergent one-loop lattice Feynman integrals I(p,a), subject to mild general conditions, we prove the following expected and crucial structural result: I(p,a) = f(p)log(aM)+g(p)+h(p,M) up to terms which vanish for lattice spacing a -> 0. Here p denotes collectively the external momenta and M is a mass scale which may be chosen arbitrarily

F. Yuasa, E. de Doncker, J. Fujimoto, N. Hamaguchi

We present a new approach for obtaining very precise integration results for infrared vertex and box diagrams, where the integration is carried out directly without performing any analytic integration of Feynman parameters. Using an appropriate numerical integration routine with an extrapolation method, together with a multi-precision library, we have obtain

Yong-Wan Kim, Young-Jai Park

We calculate the statistical entropy of a scalar field on the background of (2+1)-dimensional de Sitter space without an artificial cutoff considering corrections to all orders in the Planck length from a generalized uncertainty principle (GUP) on the quantum state density. The desired entropy proportional to the horizon perimeter is obtained.

Martin Reiris

We introduce the notion of general K=-1 Friedman-Lemaître (compact) cosmologies and the notion of averaged evolution by means of an averaging map. We then analyze the Friedman-Lemaître equations and the role of gravitational energy on the universe evolution. We distinguish two asymptotic behaviors: radiative and mass gap. We discuss the averaging problem in

Robert S. Hoy, Mark O. Robbins

Simulations are used to examine the microscopic origins of strain hardening in polymer glasses. While stress-strain curves for a wide range of temperature can be fit to the functional form predicted by entropic network models, many other results are fundamentally inconsistent with the physical picture underlying these models. Stresses are too large to be ent

LIGO Scientific Collaboration

We present the results of a search for short-duration gravitational-wave bursts associated with 39 gamma-ray bursts (GRBs) detected by gamma-ray satellite experiments during LIGO&#39;s S2, S3, and S4 science runs. The search involves calculating the crosscorrelation between two interferometer data streams surrounding the GRB trigger time. We search for assoc

Hye-Sung Lee, Konstantin T. Matchev, Ting T. Wang

The Minimal Supersymmetric Standard Model (MSSM) is plagued by two major fine-tuning problems: the mu-problem and the proton decay problem. We present a simultaneous solution to both problems within the framework of a U(1)&#39;-extended MSSM (UMSSM), without requiring R-parity conservation. We identify several classes of phenomenologically viable models and

C. C. Cheung, L. Stawarz, D. E. Harris, M. Ostrowski

We report new detections of the hotspots in Cygnus A at 4.5 and 8.0 microns with the Spitzer Space Telescope. Together with detailed published radio observations and synchrotron self-Compton modeling of previous X-ray detections, we reconstruct the underlying electron energy spectra of the two brightest hotspots (A and D). The low-energy portion of the elect

Naiomi Cameron, Kendra Killpatrick

We extend the notion of $k$-ribbon tableaux to the Fibonacci lattice, a differential poset defined by R. Stanley in 1975. Using this notion, we describe an insertion algorithm that takes $k$-colored permutations to pairs of $k$-ribbon Fibonacci tableaux of the same shape, and we demonstrate a color-to-spin property, similar to that described by Shimozono and

P. C. Gregory

A Bayesian multi-planet Kepler periodogram has been developed for the analysis of precision radial velocity data (Gregory 2005b and 2007). The periodogram employs a parallel tempering Markov chain Monte Carlo algorithm. The HD 11964 data (Butler et al. 2006) has been re-analyzed using 1, 2, 3 and 4 planet models. Assuming that all the models are equally prob

G. B. Taylor, S. E. Healey, J. F. Helmboldt, S. Tremblay

We examine the radio properties of EGRET-detected blazars observed as part of the VLBA Imaging and Polarimetry Survey (VIPS). VIPS has a flux limit roughly an order of magnitude below the MOJAVE survey and most other samples that have been used to study the properties of EGRET blazars. At lower flux levels, radio flux density does not directly correlate with

Mark McCann, Nicholas Pippenger

A commonly used model for fault-tolerant computation is that of cellular automata. The essential difficulty of fault-tolerant computation is present in the special case of simply remembering a bit in the presence of faults, and that is the case we treat in this paper. We are concerned with the degree (the number of neighboring cells on which the state transi

Harish Sethu

In this report, we consider maximal solutions to the induced bounded-degree subgraph problem and relate it to issues concerning stream control in multiple-input multiple-output (MIMO) networks. We present a new distributed algorithm that completes in logarithmic time with high probability and is guaranteed to complete in linear time. We conclude the report w

Thomas Vojta

This article first gives a concise introduction to quantum phase transitions, emphasizing similarities with and differences to classical thermal transitions. After pointing out the computational challenges posed by quantum phase transitions, a number of successful computational approaches is discussed. The focus is on classical and quantum Monte Carlo method

D. DeMille, S. Sainis, J. Sage, T. Bergeman

We propose new experiments with high sensitivity to a possible spatial or temporal variation of the electron-to-proton mass ratio $μ\equiv m_e/m_p$. We consider a nearly-degenerate pair of molecular vibrational levels, where each state is associated with a different electronic potential. The change in the splitting between such levels, with respect to a chan

Hai-Yang Cheng

Spectroscopy and strong decays of the charmed baryons are reviewed. Possible spin-parity quantum numbers of several newly observed charmed baryon resonances are discussed. Strong decays of charmed baryons are analyzed in the framework of heavy hadron chiral perturbation theory in which heavy quark symmetry and chiral symmetry are synthesized.

Max-Louis G. Buot, Serkan Hosten, Donald St. P. Richards

Let $μ$ be a $p$-dimensional vector, and let $Σ_1$ and $Σ_2$ be $p \times p$ positive definite covariance matrices. On being given random samples of sizes $N_1$ and $N_2$ from independent multivariate normal populations $N_p(μ,Σ_1)$ and $N_p(μ,Σ_2)$, respectively, the Behrens-Fisher problem is to solve the likelihood equations for estimating the unknown para

Stephen Boyd, Persi Diaconis, Pablo A. Parrilo, Lin Xiao

We show how to exploit symmetries of a graph to efficiently compute the fastest mixing Markov chain on the graph (i.e., find the transition probabilities on the edges to minimize the second-largest eigenvalue modulus of the transition probability matrix). Exploiting symmetry can lead to significant reduction in both the number of variables and the size of ma

Dr Julia A. Berashevich, Vadim Apalkov, Tapash Chakraborty

The formation of polaron and its migration in a DNA chain are studied within a semiclassical Peyrard-Biship-Holstein polaron model. Comparing the energetics of the polaron system found from the quantum chemical and semiclassical calculations, we extract the charge-phonon coupling constant for poly DNA sequences. The coupling constant is found to be larger fo

Y. Y. Kovalev

We report new results from a sub-parsec scale study of the inner jet in M87 performed at 15 GHz with the Very Long Baseline Array. We have detected a limb brightened structure of the jet along with a faint 3 mas long counter-feature which we also find to be limb brightened. Typical speeds of separate jet features are measured to be less than 0.05 speed of li

Evan Scannapieco, Robert J. Thacker, H. M. P. Couchman

One of the most important and poorly-understood issues in structure formation is the role of outflows driven by active galactic nuclei (AGN). Using large-scale cosmological simulations, we compute the impact of such outflows on the small-scale distribution of the cosmic microwave background (CMB). Like gravitationally-heated structures, AGN outflows induce C

V. V. Makarov, N. Zacharias, G. S. Hennessy, H. C. Harris

We report a late M-type, common proper motion companion to a nearby young visual binary HIP 115147 (V368 Cep), separated by 963 arcseconds from the primary K0 dwarf. This optically dim star has been identified as a candidate high proper motion, nearby dwarf LSPM J2322+7847 by L{é}pine in 2005. The wide companion is one of the latest post-T Tauri low mass sta

T. A. Bell, W. Whyatt, S. Viti, M. P. Redman

We have carried out a systematic search for the molecular ion CO+ in a sample of 8 protoplanetary and planetary nebulae in order to determine the origin of the unexpectedly strong HCO+ emission previously detected in these sources. An understanding of the HCO+ chemistry may provide direct clues to the physical and chemical evolution of planetary nebulae. We

Pieter van Dokkum, Asantha Cooray, Ivo Labbe, Casey Papovich

IRAC excels at detecting distant objects. Due to a combination of the shapes of the spectral energy distributions of galaxies and the low background achieved from space, IRAC reaches greater depth in comparable exposure time at 3.6 and 4.5 micron than any ground- or space-based facility currently can at 2.2 micron. Furthermore, the longer wavelengths probed

J. H. Debes, S. Sigurdsson

During planet formation, a gas giant will interact with smaller protoplanets that stray within its sphere of gravitational influence. We investigate the outcome of interactions between gas giants and terrestrial-sized protoplanets with lunar-sized companions. An interaction between a giant planet and a protoplanet binary may have one of several consequences,

Michael Endl, William D. Cochran, Robert A. Wittenmyer, Alan P. Boss

We report the detection of a planetary companion with a minimum mass of m sin i = 0.0771 M_Jup = 24.5 M_Earth to the nearby (d = 9.4 pc) M2.5V star GJ 176. The star was observed as part of our M dwarf planet search at the Hobby-Eberly Telescope (HET). The detection is based on 5 years of high-precision differential radial velocity (RV) measurements using the

Wenliang Zhang

In this paper we study the commutativity of the Frobenius functor and the colon operation of two ideals for Noetherian rings of positive characteristic $p$. New characterizations of regular rings and local UFDs are given.

David Garfinkle, Greg Comer

GGR News: -we hear that..., by David Garfinkle -News from the GRG Society, by Abhay Ashtekar -LIGO/GEO/Virgo work together, by Peter Saulson -GWIC Ten Years on, by Stan Whitcomb Research Briefs: -Quasi-local energy, by Bjoern S. Schmekel -The current status of cosmic strings, by Patrick Peter -Gravitational waves from `mountains&#39; on neutron stars, by Ian

Bruno Preziosi, Erasmo Recami

Ettore Majorana was a member of Enrico Fermi's research group in Rome, Italy. Fermi did regard Majorana as much brihter than himself as far as theoretical physics was concerned (more information can be found particularly in the arXives' e-print physics/9810023, in Italian, and refs therein, and also in the recent multilanguage arXiv:0708.2855v1 [physics.hist

Kazuhiro Hayama, Soumya D. Mohanty, Malik Rakhmanov, Shantanu Desai

Searches for gravitational wave bursts that are triggered by the observation of astronomical events require a different mode of analysis than all-sky, blind searches. For one, much more prior information is usually available in a triggered search which can and should be used in the analysis. Second, since the data volume is usually small in a triggered searc

G. Kontrym-Sznajd, M. Samsel-Czekala, G. E. Grechnev, H. Sormann

We discuss an efficiency of various band structure algorithms in determining the Fermi surface (FS) of the paramagnetic ErGa3. The linear muffin-tin orbital (LMTO) in the atomic sphere approximation (ASA) method and three full potential (FP) codes: FP-LMTO, FP linear augmented plane wave (FLAPW), and FP local orbitals (FPLO) methods are employed. Results are

Serkan Hosten, Seth Sullivant

We study the problem of maximum likelihood estimation for general patterns of bivariate missing data for normal and multinomial random variables, under the assumption that the data is missing at random (MAR). For normal data, the score equations have nine complex solutions, at least one of which is real and statistically significant. Our computations suggest

László Á. Gergely, Zoltán Keresztes, Gyula M. Szabó

A class of generalized Randall-Sundrum type II (RS) brane-world models with Weyl fluid are confronted with the Gold supernovae data set and BBN constraints. We consider three models with different evolutionary history of the Weyl fluid, characterized by the parameter $α$. For $α=0$ the Weyl curvature of the bulk appears as dark radiation on the brane, while

Anna Hasenfratz, Roland Hoffmann, Stefan Schaefer

In a system where chiral symmetry is spontaneously broken, the low energy eigenmodes of the continuum Dirac operator are extended. On the lattice, due to discretization effects, the Dirac operator can have localized eigenmodes that affect physical quantities sensitive to chiral symmetry. While the infrared eigenmodes of the Wilson Dirac operator are usually

A. M. Frydryszak, V. M. Tkachuk

We study quantum brachistochrone problem for the spin-1 system in a magnetic field of a constant absolute value. Such system gives us a possibility to examine in detail the statement of papers [A. Carlini {\it et al.}, Phys. Rev. Lett. {\bf 96}, 060503 (2006), D. C. Brody, D. W. Hook, J. Phys. A {\bf 39}, L167, (2006)] that {\it the state vectors realizing t

V. Gudkov, V. Montealegre

Generalized mutual entropy is defined for networks and applied for analysis of complex network structures. The method is tested for the case of computer simulated scale free networks, random networks, and their mixtures. The possible applications for real network analysis are discussed.

Jianyong Sun, Ata Kaban, Somak Raychaudhury

We develop a mixture-based approach to robust density modeling and outlier detection for experimental multivariate data that includes measurement error information. Our model is designed to infer atypical measurements that are not due to errors, aiming to retrieve potentially interesting peculiar objects. Since exact inference is not possible in this model,

Rajendran Raja

We outline a physics program at Fermilab that would significantly improve our ability to understand the behavior of hadronic showers in calorimeters. This would involve a two-pronged approach designed to measure particle production cross sections of hadronic beams on several nuclei to improve shower simulation programs and the validation of the improved show

Ales Psaker

We investigate the extension of the deeply virtual Compton scattering process into the weak interaction sector.

E. M. L. Humphreys, M. J. Reid, L. J. Greenhill, J. M. Moran

We report measurements of centripetal accelerations of maser spectral components of NGC 4258 for 51 epochs spanning 1994 to 2004. This is the second paper of a series, in which the goal is determination of a new geometric maser distance to NGC 4258 accurate to possibly ~3%. We measure accelerations using a formal analysis method that involves simultaneous de

M. Blasone, A. Capolupo, S. Capozziello, G. Vitiello

We report on the recent result that a contribution to the dark energy can be achieved by the vacuum condensate induced by neutrino mixing phenomenon.

Alfredo Braunstein, Roberto Mulet, Andrea Pagnani

In this work we propose a novel algorithmic strategy that allows for an efficient characterization of the whole set of stable fluxes compatible with the metabolic constraints. The algorithm, based on the well-known Bethe approximation, allows the computation in polynomial time of the volume of a non full-dimensional convex polytope in high dimensions. The re

G. Nimtz, A. A. Stahlhofen

Tunneling is an important physical process. The observation that particles surmount a high mountain in spite of the fact that they don&#39;t have the necessary energy cannot be explained by classical physics. However, this so called tunneling became allowed by quantum mechanics. Experimental tunneling studies with different photonic barriers from microwave f

M. Gullieuszik, M. Rejkuba, M. R. Cioni, H. J. Habing

We investigate the intermediate-age asymptotic giant branch stellar population of two Local Group dwarf irregular galaxies to characterize their carbon star population in near-infrared (IR). Our work is based on J and K-band SOFI near-IR photometry complemented with optical ground based and HST photometry. We show that near-IR photometry is a very powerful t

Michael Skeide

The theory of product systems both of Hilbert spaces (Arveson systems) and product systems of Hilbert modules has reached a status where it seems appropriate to rest a moment and to have a look at what is known so far and what are open problems. However, the attempt to give an approximately complete account in view pages is destined to fail already for Arves

V Janis, P. Augustinsky

The low-temperature behavior of the asymmetric single-impurity Anderson model is studied by diagrammatic methods resulting in analytically controllable approximations. We first discuss the ways one can simplify parquet equations in critical regions of singularities in the two-particle vertex. The scale vanishing at the critical point defines the Kondo temper

Jesus Hernandez, Nuria Calvet, C. Briceno, L. Hartmann

We present new Spitzer Space Telescope observations of two fields in the Orion OB1 association. We report here IRAC/MIPS observations for 115 confirmed members and 41 photometric candidates of the ~10 Myr 25 Orionis aggregate in the OB1a subassociation, and 106 confirmed members and 65 photometric candidates of the 5 Myr region located in the OB1b subassocia

Avraham Ben-Aroya, Oded Schwartz, Amnon Ta-Shma

Quantum expanders are a natural generalization of classical expanders. These objects were introduced and studied by Ben-Aroya and Ta-Shma and by Hastings. In this note we show how to construct explicit, constant-degree quantum expanders. The construction is essentially the classical Zig-Zag expander construction, applied to quantum expanders.

Biagio Lucini, Agostino Patella, Claudio Pica

In a compact space with non-trivial cycles, for sufficiently small values of the compact dimensions, charge conjugation (C), spatial reflection (P) and time reversal (T) are spontaneously broken in QCD. The order parameter for the symmetry breaking is the trace of the Wilson line wrapping around the compact dimension, which acquires an imaginary part in the

Charles E. Woodward, Michael S. Kelley, Dominique Bockelee-Morvan, R. D. Gehrz

We present sensitive 5.5 to 7.6 micron spectra of comet C/2003 K4 (LINEAR) obtained on 16 July 2004 (r_{h} = 1.760 AU, Delta_{Spitzer} = 1.409 AU, phase angle 35.4 degrees) with the Spitzer Space Telescope. The nu_{2} vibrational band of water is detected with a high signal-to-noise ratio (> 50). Model fitting to the best spectrum yields a water ortho-to-par

Sylvain Boussier, Hideki Hashimoto, Michel Vasquez

The subject of the 5th challenge proposed by the French Society of Operations Research and Decision Analysis (ROADEF) consists in scheduling technicians and interventions for telecommunications (http://www.g-scop.inpg.fr/ChallengeROADEF2007/ or http://www.roadef.org/). We detail the algorithm we proposed for this challenge which is a Greedy Randomized Adapta

Adrian Constantin, David Lannes

In recent years two nonlinear dispersive partial differential equations have attracted a lot of attention due to their integrable structure. We prove that both equations arise in the modeling of the propagation of shallow water waves over a flat bed. The equations capture stronger nonlinear effects than the classical nonlinear dispersive Benjamin-Bona-Mahone

Klaus Fabricius, Barry M. McCoy

We extend our studies of the TQ equation introduced by Baxter in his 1972 solution of the 8 vertex model with parameter $η$ given by $2Lη=2m_1K+im_2K&#39;$ from $m_2=0$ to the more general case of complex $η.$ We find that there are several different cases depending on the parity of $m_1$ and $m_2$.

G. Baskaran

Electrical and magnetic properties of underdoped cuprates in the spin gap phase, a precursor to high Tc superconducting state, is riddled with puzzles. We propose a novel reference state to study this phase, where each hole dopant adds one real holon and one real spinon, with Haldane exclusion statistics $g_{\rm h} =1$ and $g_{\rm s} = {1/2}$, to a fairly in

A. Afanasev, M. Strikman, C. Weiss

We study the transverse target spin dependence of the cross section for inclusive electron-nucleon scattering with unpolarized beam. Such dependence is absent in the one-photon exchange approximation (Christ-Lee theorem) and arises only in higher orders of the QED expansion, from the interference of one-photon and absorptive two-photon exchange amplitudes as

Hitoshi Yamamoto

International Linear Collider (ILC) is an electron-positron collider with the initial center-of-mass energy of 500 GeV which is upgradable to about 1 TeV later on. Its goal is to study the physics at TeV scale with unprecedented high sensitivities. The main topics include precision measurements of the Higgs particle properties, studies of supersymmtric parti

Michael Maziashvili

Operational definition of space-time in light of quantum mechanics and general relativity inevitably indicates an intrinsic imprecision in space-time structure which has to do with space-time dimension as well. The operational dimension of space-time turns out to be a scale dependent quantity slightly smaller than four at distances $\gg l_P$. Close to the Pl

David A. Craven

In this article we prove the following result: that for any two natural numbers k and j, and for all sufficiently large symmetric groups Sym(n), there are k disjoint sets of j irreducible characters of Sym(n), such that each set consists of characters with the same degree, and distinct sets have different degrees. In particular, this resolves a conjecture mo

Michael J. Kurtz, Edwin A. Henneken

We demonstrate conclusively that there is no &#34;Open Access Advantage&#34; for papers from the Astrophysical Journal. The two to one citation advantage enjoyed by papers deposited in the arXiv e-print server is due entirely to the nature and timing of the deposited papers. This may have implications for other disciplines.

D. R. Murray, P Öhberg, Damiá Gomila, Stephen M. Barnett

We numerically simulate vortex nucleation in a Bose-Einstein Condensate (BEC) subject to an effective magnetic field. The effective magnetic field is generated from the interplay between light with a non-trivial phase structure and the BEC, and can be shaped and controlled by appropriate modifications to the phase and intensity of the light. We demonstrate t

Thomas Jorg, Florent Krzakala

In a recent interesting Letter Contucci {\it et al.} have investigated several properties of the three-dimensional (3d) Edwards-Anderson (EA) Ising spin glass. They claim to have found strong numerical evidence for the presence of a complex ultrametric structure similar to the one described by the replica symmetry breaking solution of the mean field model. W

Rahul Pandit, Samriddhi Sankar Ray, Dhrubaditya Mitra

We give an overview of the progress that has been made in recent years in understanding the dynamic multiscaling of homogeneous, isotropic turbulence and related problems. We emphasise the similarity of this problem with the dynamic scaling of time-dependent correlation functions in the vicinity of a critical point in, e.g., a spin system. The universality o

R. B. Mann, G. L. Murphy

We investigate the quantum evolution of the metric operators for Bianchi-Type I model universes in the Heisenberg picture in order to remove the need to consider the wave function of the universe and interpret its &#34;spin&#34; variables. The calculation is analogous to that of the Zitterbewegung of the Dirac electron. We consider the behavior of the metric

A. Gomez-Marin, J. M. Sancho

A Brownian pump of particles powered by a stochastic flashing ratchet mechanism is studied. The pumping device is embedded in a finite region and bounded by particle reservoirs. In the steady state, we exactly calculate the spatial density profile, the concentration ratio between both reservoirs and the particle flux. A simple numerical scheme is presented a