December 2007 arXiv papers — page 12

Hye-Sung Lee, Christoph Luhn, Konstantin T. Matchev

The Minimal Supersymmetric Standard Model (MSSM) with conserved R-parity suffers from several fine-tuning problems, e.g. the mu-problem and the problem of proton decay through higher dimension operators. Both of these problems can be avoided by replacing R-parity with a non-anomalous U(1)' gauge symmetry which is broken at the TeV scale. The new gauge sy

Michael Schürmann, Michael Skeide, Silvia Volkwardt

A Lévy process on a *-bialgebra is given by its generator, a conditionally positive hermitian linear functional vanishing at the unit element. A *-algebra homomorphism k from a *-bialgebra C to a *-bialgebra B with the property that k respects the counits maps generators on B to generators on C. A tranformation between the corrresponding two Lévy processes i

Mustafa Cenk Gursoy

The central design challenge in next generation wireless systems is to have these systems operate at high bandwidths and provide high data rates while being cognizant of the energy consumption levels especially in mobile applications. Since communicating at very high data rates prohibits obtaining high bit resolutions from the analog-to-digital (A/D) convert

Lia Vas

We define and study the symmetric version of differential torsion theories. We prove that the symmetric versions of some of the existing results on derivations on right modules of quotients hold for derivations on symmetric modules of quotients. In particular, we prove that the symmetric Lambek, Goldie and perfect torsion theories are differential. We also s

Veniamin Berezinsky, Vyacheslav Dokuchaev, Yury Eroshenko

What happened to the central cores of tidally destructed dark matter clumps in the Galactic halo? We calculate the probability of surviving of the remnants of dark matter clumps in the Galaxy by modelling the tidal destruction of the small-scale clumps. It is demonstrated that a substantial fraction of clump remnants may survive through the tidal destruction

Lia Vas

Perfect Gabriel filters of right ideals and their corresponding right rings of quotients have the desirable feature that every module of quotients is determined solely by the right ring of quotients. On the other hand, symmetric rings of quotients have a symmetry that mimics the commutative case. In this paper, we study rings of quotients that combine these

Yaron Oz, Stefan Theisen, Shimon Yankielowicz

We consider gluon and gluino scattering amplitudes in large N beta-deformed N=4 SYM with real beta. A direct inspection of the planar diagrams shows that the scattering amplitudes to all orders in perturbation theory are the same as in the undeformed N=4 SYM theory. Using the dual sigma-model description, we find the same equality at strong coupling to all o

Davoud Cheraghi

We prove combinatorial rigidity of infinitely renormalizable unicritical polynomials, P_c :z \mapsto z^d+c, with complex c, under the a priori bounds and a certain "combinatorial condition". This implies the local connectivity of the connectedness loci (the Mandelbrot set when d = 2) at the corresponding parameters.

Eric Benhamou, Emmanuel Gobet, Mohammed Miri

Using Malliavin calculus techniques, we derive an analytical formula for the price of European options, for any model including local volatility and Poisson jump process. We show that the accuracy of the formula depends on the smoothness of the payoff function. Our approach relies on an asymptotic expansion related to small diffusion and small jump frequency

Marcel Bökstedt, Robert R. Bruner, Sverre Lunøe--Nielsen, John Rognes

For a finite p-group G and a bounded below G-spectrum X of finite type mod p, the G-equivariant Segal conjecture for X asserts that the canonical map X^G --> X^{hG} is a p-adic equivalence. Let C_{p^n} be the cyclic group of order p^n. We show that if the C_p Segal conjecture holds for a C_{p^n} spectrum X, as well as for each of its C_{p^e} geometric fixed

Eeuwe S. Zijlstra, Nils Huntemann, Martin E. Garcia

In Arsenic a pressure-induced solid-solid phase transition from the A7 into the simple cubic structure has been experimentally demonstrated [Beister et al., Phys. Rev. B 41, 5535 (1990)]. In this paper we present calculations, which predict that this phase transition can also be induced by an ultrashort laser pulse in As under pressure. In addition, calculat

Chris Clarkson, Bruce A. Bassett, Teresa Hui-Ching Lu

The recent discovery of apparent cosmic acceleration has highlighted the depth of our ignorance of the fundamental properties of nature. It is commonly assumed that the explanation for acceleration must come from a new form of energy dominating the cosmos - dark energy - or a modification of Einstein's theory of Relativity. It is often overlooked, howeve

Robert J. Scherrer, A. A. Sen

The thawing quintessence model with a nearly flat potential provides a natural mechanism to produce an equation of state parameter, w, close to -1 today. We examine the behavior of such models for the case in which the potential satisfies the slow roll conditions: [(1/V)(dV/dphi)]^2 << 1 and (1/V)(d^2 V/dphi^2) << 1, and we derive the analog of the slow-roll

Tim Wouters

In this text we investigate the good behaviour of the elementary obstruction, introduced by Colliot-Thelene and Sansuc. This is an obstruction to the existence of a rational points on certain algebraic varieties. Assuming some conditions on the Picard group, we prove that the elementary obstruction behaves well under the Weil restriction of a variety.

M. Demiański, A. G. Doroshkevich

We analyze basic properties of about 200 metal systems observed in high resolution spectra of 9 quasars by Boksenberg, Sargent & Rauch (2003). The measured Doppler parameters for the hydrogen and carbon lines are found to be different by a factor $\sim\sqrt{m_C/ m_H}$ what indicates the domination of the thermal broadening and high degree of relaxation for m

Christian Miebach

Let $G$ be a real-reductive Lie group and let $G_1$ and $G_2$ be two subgroups given by involutions. We show how the technique of gradient maps can be used in order to obtain a new proof of Matsuki&#39;s parametrization of the closed double cosets $G_1\backslash G/G_2$ by Cartan subsets. We also describe the elements sitting in non-closed double cosets.

Celso de Camargo Barros, Yogiro Hama

Recent experiments at RHIC have shown that in 200 GeV Au-Au collisions, the Lambda and Antilambda hyperons are produced with very small polarizations [1], almost consistent with zero. These results can be understood in terms of a model that we recently proposed [2]. In this work, we show how this model may be applied in such collisions, and also will discuss

Jacob Mostovoy

Dold-Thom functors are generalizations of infinite symmetric products, where integer multiplicities of points are replaced by composable elements of a partial abelian monoid. It is well-known that for any connective homology theory, the machinery of $Γ$-spaces produces the corresponding linear Dold-Thom functor. In this note we construct such functors direct

Keiichi Umetsu, Tom Broadhurst

[Abridged] We derive a projected 2D mass map of the well studied galaxy cluster A1689 based on an entropy-regularized maximum-likelihood combination of the lens magnification and distortion of red background galaxies registered in deep Subaru images. The known strong lensing information is also readily incorporated in this approach, represented as a central

John Ove Fjaerestad

We use a wave functional approach to calculate the fidelity of ground states in the Luttinger liquid universality class of one-dimensional gapless quantum many-body systems. The ground-state wave functionals are discussed using both the Schrodinger (functional differential equation) formulation and a path integral formulation. The fidelity between Luttinger

Alexander Leitsch, Guenter Schachner, Karl Svozil

We discuss the question of how to operationally validate whether or not a &#34;hypercomputer&#34; performs better than the known discrete computational models.

Francesco Caravenna, Nicolas Pétrélis

We consider a model for a polymer chain interacting with a sequence of equispaced flat interfaces through a pinning potential. The intensity $δ\in \mathbb {R}$ of the pinning interaction is constant, while the interface spacing $T=T_N$ is allowed to vary with the size $N$ of the polymer. Our main result is the explicit determination of the scaling behavior o

Erik I. Broman, Federico Camia

We study Mandelbrot&#39;s percolation process in dimension $d \geq 2$. The process generates random fractal sets by an iterative procedure which starts by dividing the unit cube $[0,1]^d$ in $N^d$ subcubes, and independently retaining or discarding each subcube with probability $p$ or $1-p$ respectively. This step is then repeated within the retained subcube

Jean-Paul Ibrahim

Following the recent investigations of Baik and Suidan in \cite{baik2005gcl} and Bodineau and Martin in \cite{bodineau2005upl}, we prove large deviation properties for a last-passage percolation model in $\mathbb{Z}^{2}_{+}$ whose paths are close to the axis. The results are mainly obtained when the random weights are Gaussian or have a finite moment-generat

Craig J. Hogan

A particular form for the quantum indeterminacy of relative spacetime position of events is derived from the limits of measurement possible with Planck wavelength radiation. The indeterminacy predicts fluctuations from a classically defined geometry in the form of ``holographic noise'' whose spatial character, absolute normalization, and spectrum are predict

Remi Rhodes

We investigate a functional limit theorem (homogenization) for Reflected Stochastic Differential Equations on a half-plane with stationary coefficients when it is necessary to analyze both the effective Brownian motion and the effective local time. We prove that the limiting process is a reflected non-standard Brownian motion. Beyond the result, this problem

Emmanuel Frenod, Olivier Sire

In this paper we explain the biophysical principles which, according to us, govern the Proteus mirabilis swarm phenomenon. Then, we translate this explanation into a mathematical model, essentially based on partial differential equations. This model is then implemented using numerical methods of the finite volume type in order to make simulations. The simula

Carla Novelli, Gianluca Occhetta

We classify smooth complex projective varieties $X \subset \proj^N$ of dimension $2s+1$ containing a linear subspace $Λ$ of dimension $s$ whose normal bundle $N_{Λ/X}$ is numerically effective.

Joan Soto, Jaume Tarrus

We propose a low energy effective field theory of QCD at the scale of pion mass for the $N_B=2$ sector, $N_B$ being the baryon number, which contains two dibaryon fields in addition to the nucleons and pions. It has a well defined counting, is renormalizable and the nucleon-nucleon scattering amplitudes are manifestly unitary at leading order. We work out a

Francesco D&#39;Andrea, Ludwik Dabrowski, Giovanni Landi

We study the spectral geometry of the quantum projective plane CP^2_q, a deformation of the complex projective plane CP^2, the simplest example of a spin^c manifold which is not spin. In particular, we construct a Dirac operator D which gives a 0^+ summable spectral triple, equivariant under U_q(su(3)). The square of D is a central element for which left and

Kiran S. Kedlaya

We complete our proof that given an overconvergent F-isocrystal on a variety over a field of positive characteristic, one can pull back along a suitable generically finite cover to obtain an isocrystal which extends, with logarithmic singularities and nilpotent residues, to some complete variety. We also establish an analogue for F-isocrystals overconvergent

R. F. Avila, M. J. Menon

By means of improved empirical fits to the differential cross section data on $pp$ elastic scattering at $19.4 \le\sqrt{s}\le 62.5$ GeV and making use of a semi-analytical method, we determine the eikonal in the momentum transfer space (the inverse scattering problem). This method allows the propagation of the uncertainties from the fit parameters up to the

Yongli Ping, Lixin Xu, Baorong Chang, Hongya Liu

Current universe (assumed here to be normal matter on the brane) is pressureless from observations. In this case the energy condition is $ρ_0\geq0$ and $p_0=0$. By using this condition, brane models can be distinguished. Then, assuming arbitrary component of matter in DGP model, we use four known energy conditions to study the matter on the brane. If there i

Marina Marchisio, Vittorio Perduca

We study semi-stable degenerations of toric varieties determined by certain partitions of their moment polytopes. Analyzing their defining equations we prove a property of uniqueness.

Katrin Steinberg, Marc Scheffler, Martin Dressel

The response of superconducting aluminum to electromagnetic radiation is investigated in a broad frequency (45 MHz to 40 GHz) and temperature range ($T>T_c/2$), by measuring the complex conductivity. While the imaginary part probes the superfluid density (Cooper-pairs), the real part monitors the opening of the superconducting energy gap and -- most importan

Mihai Mariş

For a large class of variational problems we prove that minimizers are symmetric whenever they are $C^1$.

Christoph Adam, Joaquin Sanchez-Guillen, Andrzej Wereszczynski

We briefly review the concepts of generalized zero curvature conditions and integrability in higher dimensions, where integrability in this context is related to the existence of infinitely many conservation laws. Under certain assumptions, it turns out that these conservation laws are, in fact, generated by a class of geometric target space transformations,

A. Khalatyan, A. Cattaneo, M. Schramm, S. Gottloeber

We have used GADGET2 to simulate the formation of an elliptical galaxy in a cosmological dark matter halo with mass 3x10^12M_Sun/h. Using a stellar population synthesis model has allowed us to compute magnitudes, colours and surface brightness profiles. We have included a model to follow the growth of a central black hole and we have compared the results of

Lionel Levine, Yuval Peres

We study the scaling limits of three different aggregation models on Z^d: internal DLA, in which particles perform random walks until reaching an unoccupied site; the rotor-router model, in which particles perform deterministic analogues of random walks; and the divisible sandpile, in which each site distributes its excess mass equally among its neighbors. A

David Krejcirik

We make an overview of spectral-geometric effects of twisting and bending in quantum waveguides modelled by the Dirichlet Laplacian in an unbounded three-dimensional tube of uniform cross-section. We focus on the existence of Hardy-type inequalities in twisted tubes of non-circular cross-section.

H. Kohler, I. Smolyarenko, C. Pineda, T. Guhr

Unexpected relations between fidelity decay and cross form--factor, i.e., parametric level correlations in the time domain are found both by a heuristic argument and by comparing exact results, using supersymmetry techniques, in the framework of random matrix theory. A power law decay near Heisenberg time, as a function of the relevant parameter, is shown to

W. Pusz, P. M. Soltan

This paper is an adaptation of a chapter from an upcoming monograph on noncommutative geometry and quantum groups. We present examples of non compact quantum groups which are deformations of low dimensional Lie groups. The paper is of expository nature and provides both particular examples and some general procedures for constructing them.

Andrea Marini

The coupling with the lattice vibrations is shown to drastically modify the state--of--the--art picture of the excitonic states based on a frozen atom approximation. The zero--point vibrations renormalize the bare energies and optical strengths. Excitons acquire a non--radiative lifetime that decreases with increasing temperature. The optical brightness and

S. M. Troshin

This is a comment on the recent paper by O.V. Selyugin, J.-R. Cudell, and E. Predazzi &#34;Analytic properties of different unitarization schemes&#34; arXiv: 0712.0621v2, [hep-ph]

Dror Orgad

We study the superconducting transition temperature, T_c, of an array of fluctuating, maximally gapped interacting ladders, embedded in a disordered plane. Renormalization group analysis indicates that geometrical fluctuations mitigate the suppression of the intra-ladder pairing correlations by the disorder. In addition, the fluctuations enhance the Josephso

Margarita Safonova, C. Sivaram, Jayant Murthy

Transient events have posed special problems in astronomy because of the intrinsic difficulty of their detection, and a new class of observatories such as the Pan-STARRS and LSST are coming up specifically to observe these energetic events. In this paper we discuss the UV transient events from two specific sources, such as possible collisions in extrasolar p

Xin Li, Tian Liu

M.Aleknovich et al. have recently proposed a model of algorithms, called BT model, which generalizes both the priority model of Borodin, Nielson and Rackoff, as well as a simple dynamic programming model by Woeginger. BT model can be further divided into three kinds of fixed, adaptive and fully adaptive ones. They have proved exponential time lower bounds of

Tetsuo Hyodo, Daisuke Jido, Luis Roca

We study the behavior with the number of colors (Nc) of the two poles associated to the Lambda(1405) resonance obtained dynamically within the chiral unitary approach. The leading order chiral meson-baryon interaction manifests a nontrivial Nc dependence for SU(3) baryons, which gives a finite attractive interaction in some channels in the large Nc limit. As

W. H. Z. Cardenas, M. S. Hussein, L. F. Canto, J. Lubian

We discuss the derivation of an equivalent \textit{l}-independent polarization potential for use in the optical Schrödinger equation that describes the elastic scattering of heavy ions. Three diffferent methods are used for this purpose. Application of our theory to the low energy scattering of the halo nucleus $^{11}$Li from a $^{12}$C target is made. It is

D. Vanbeveren, H. Belkus, J. Van Bever, N. Mennekens

In the present paper we combine an N-body code that simulates the dynamics of young dense stellar systems with a massive star evolution handler that accounts in a realistic way for the effects of stellar wind mass loss. We discuss two topics: 1. The formation and the evolution of very massive stars (with a mass >120 Mo) is followed in detail. These very mass

Ryusuke Ikeda

This is a Comment on Phys.Rev.Lett. 100, 017001 (2008).

I. D. Kosińska, I. Goychuk, M. Kostur, G. Schmid

Ion transport in biological and synthetic nanochannels is characterized by phenomena such as ion current fluctuations and rectification. Recently, it has been demonstrated that nanofabricated synthetic pores can mimic transport properties of biological ion channels [P. Yu. Apel, {\it et al.}, Nucl. Instr. Meth. B {\bf 184}, 337 (2001); Z. Siwy, {\it et al.},

Yves Grandati, Alain Berard, Herve Mohrbach

In the category of motions preserving the angular momentum&#39;s direction, Gorringe and Leach exhibited two classes of differential equations having elliptical orbits. After enlarging slightly these classes, we show that they are related by a duality correspondence of the Arnold-Vassiliev type. The specific associated conserved quantities (Laplace-Runge-Len

Thomas Butler, Nigel Goldenfeld, Damien Mathew, Zaida Luthey-Schulten

A molecular dynamics calculation of the amino acid polar requirement is presented and used to score the canonical genetic code. Monte Carlo simulation shows that this computational polar requirement has been optimized by the canonical genetic code more than any previously-known measure. These results strongly support the idea that the genetic code evolved fr

Anupam Gupta, Kunal Talwar

In recent years, considerable advances have been made in the study of properties of metric spaces in terms of their doubling dimension. This line of research has not only enhanced our understanding of finite metrics, but has also resulted in many algorithmic applications. However, we still do not understand the interaction between various graph-theoretic (to

Yun-Song Piao

In this paper, in a class of warped compactifications with the brane/flux annihilation, we find that the inflation may be driven by a flat direction identified as that along the number p of anti D3-branes located at the tip of the Klebanov-Strassler throat. The spectrum of adiabatic perturbation generated during inflation is nearly scale invariant, which may

Chandra Nair, Abbas El Gamal

Korner and Marton established the capacity region for the 2-receiver broadcast channel with degraded message sets. Recent results and conjectures suggest that a straightforward extension of the Korner-Marton region to more than 2 receivers is optimal. This paper shows that this is not the case. We establish the capacity region for a class of 3-receiver broad

Xuehao He, Friederike Schmid

We present an extensive computer simulation study of structure formation in amphiphilic block copolymer solutions after a quench from a homogeneous state. By using a mesoscopic field-based simulation method, we are able to access time scales in the range of a second. A phase diagram of final structures is mapped out as a function of the concentration and sol

Erhan Bayraktar, Hao Xing

In this paper we show that the optimal exercise boundary / free boundary of the American put option pricing problem for jump diffusions is continuously differentiable (except at the maturity). This differentiability result has been established by Yang et al. (European Journal of Applied Mathematics, 17(1):95-127, 2006) in the case where the condition $r\geq

Denis-Charles Cisinski, Frédéric Déglise

We define, for a regular scheme $S$ and a given field of characteristic zero $\KK$, the notion of $\KK$-linear mixed Weil cohomology on smooth $S$-schemes by a simple set of properties, mainly: Nisnevich descent, homotopy invariance, stability (which means that the cohomology of $\GG_{m}$ behaves correctly), and Künneth formula. We prove that any mixed Weil

Yun Soo Myung

We study thermodynamics of the Schwarzschild-de Sitter black hole in five dimensions by introducing two temperatures based on the standard and Bousso-Hawking normalizations. We use the first-law of thermodynamics to derive thermodynamic quantities. The two temperatures indicate that the Nariai black hole is thermodynamically unstable. However, it seems that

J. Zhou

We study the effect of the Singwi-Tosi-Land-Sjölander local field correction on spin relaxation/dephasing in $n$-type GaAs quantum wells at low temperature by constructing and numerically solving the kinetic spin Bloch equations. We calculate the local field factor $G(q)$ in quantum wells by numerically solving three equations which link the local field fact

Max N. Artyomov, Alexander Yu. Morozov, Anatoly B. Kolomeisky

Dynamics of molecular motors that move along linear lattices and interact with them via reversible destruction of specific lattice bonds is investigated theoretically by analyzing exactly solvable discrete-state ``burnt-bridge&#39;&#39; models. Molecular motors are viewed as diffusing particles that can asymmetrically break or rebuild periodically distribute

M. Schindler, A. Ajdari

We propose a simple model to analyze the traffic of droplets in microfluidic ``dual networks&#39;&#39;. Such functional networks which consist of two types of channels, namely those accessible or forbidden to droplets, often display a complex behavior characteristic of dynamical systems. By focusing on three recently proposed configurations, we offer an expl

Andreas E. Kyprianou, Ví ctor Rivero

Following from recent developments by Hubalek and Kyprianou, the objective of this paper is to provide further methods for constructing new families of scale functions for spectrally negative Lévy processes which are completely explicit. This is the result of an observation in the aforementioned paper which permits feeding the theory of Bernstein functions d

Po-Hsiang Lai, Joseph A. O&#39;Sullivan

In this paper, designs and analyses of compressive recognition systems are discussed, and also a method of establishing a dual connection between designs of good communication codes and designs of recognition systems is presented. Pattern recognition systems based on compressed patterns and compressed sensor measurements can be designed using low-density mat

E. O. Ofek, M. Muno, R. Quimby, S. R. Kulkarni

The gamma-ray burst (GRB) 070201 was a bright short-duration hard-spectrum GRB detected by the Inter-Planetary Network (IPN). Its error quadrilateral, which has an area of 0.124 sq. deg, intersects some prominent spiral arms of the nearby M31 (Andromeda) galaxy. Given the properties of this GRB, along with the fact that LIGO data argues against a compact bin

F. Schrettle, S. Krohns, P. Lunkenheimer, J. Hemberger

We present a detailed study of complex dielectric constant and ferroelectric polarization in multiferroic LiCuVO4 as function of temperature and external magnetic field. In zero external magnetic field, spiral spin order with an ab helix and a propagation vector along the crystallographic b direction is established, which induces ferroelectric order with spo

N. J. Brassington

Presented here are the highlights from the deep Chandra observation of the elliptical galaxy NGC 3379. From the multi-epoch observation of this galaxy, 132 discrete X-ray sources have been detected within the region overlapped by all observations, 98 of which lie within the D25 ellipse of the galaxy. Of these 132 sources, 71 exhibit long-term variability, in

J. A. Schreier, A. A. Houck, Jens Koch, D. I. Schuster

We present an experimental realization of the transmon qubit, an improved superconducting charge qubit derived from the Cooper pair box. We experimentally verify the predicted exponential suppression of sensitivity to 1/f charge noise [J. Koch et al., Phys. Rev. A 76, 042319 (2007)]. This removes the leading source of dephasing in charge qubits, resulting in

D. M. Worrall, M. Birkinshaw, R. P. Kraft, G. R. Sivakoff

We report an X-ray spectral study of the transverse structure of the Centaurus A jet using new data from the Chandra Cen A Very Large Project. We find that the spectrum steepens with increasing distance from the jet axis, and that this steepening can be attributed to a change in the average spectrum of the knotty emission. Such a trend is unexpected if the k

Anh-Thu Le, Toru Morishita, C. D. Lin

Based on high-order harmonic generation (HHG) spectra obtained from solving the time-dependent Schrodinger equation for atoms, we established quantitatively that the HHG yield can be expressed as the product of a returning electron wave packet and the photo-recombination cross sections, and the shape of the returning wave packet is shown to be largely indepe

Jens Braun, Bertram Klein

A non-perturbative Renormalization Group approach is used to calculate scaling functions for an O(4) model in d=3 dimensions in the presence of an external symmetry-breaking field. These scaling functions are important for the analysis of critical behavior in the O(4) universality class. For example, the finite-temperature phase transition in QCD with two fl

Benjamin D. Johnson, David Schiminovich, Mark Seibert, Marie Treyer

The meaningful comparison of models of galaxy evolution to observations is critically dependent on the accurate treatment of dust attenuation. To investigate dust absorption and emission in galaxies we have assembled a sample of ~1000 galaxies with ultraviolet (UV) through infrared (IR) photometry from GALEX, SDSS, and Spitzer and optical spectroscopy from S

Bruce Knuteson

Experimental program review in our field may benefit from a more quantitative framework within which to quantitatively discuss the scientific merit of a proposed program of research, and to assess the scientific merit of a particular experimental result. This article proposes explicitly such a quantitative framework. Examples of the use of this framework in

Edwin Wang

Recently, microRNAs (miRNAs) have emerged as central posttranscriptional regulators of gene expression. miRNAs regulate many key biological processes, including cell growth, death, development and differentiation. This discovery is challenging the central dogma of molecular biology. Genes are working together by forming cellular networks. It has become an em

Jochen Konemann, David Pritchard, Kunlun Tan

The Steiner tree problem is a classical NP-hard optimization problem with a wide range of practical applications. In an instance of this problem, we are given an undirected graph G=(V,E), a set of terminals R, and non-negative costs c_e for all edges e in E. Any tree that contains all terminals is called a Steiner tree; the goal is to find a minimum-cost Ste

Razvan Teodorescu

Recent achievements in experiments with cold fermionic atoms indicate the potential for developing novel superconducting devices which may be operated in a wide range of regimes, at a level of precision previously not available. Unlike traditional, solid-state superconducting devices, the cold-atom systems allow the fast switching on of the BCS phase, and th

A. Banu, Y. Li, M. McCleskey, M. Bullough

We report on a recently developed novel type of large area (62 mm x 62 mm) position sensitive silicon detector with four-corner readout. It consists of a square-shaped ion-implanted resistive anode framed by additional low-resistivity strips with resistances smaller than the anode surface resistance by a factor of 2. The detector position linearity, position

V. Manuilov

We give an example of a non-trivial asymptotic representation of the reduced C*-algebra of a free group. This example allows to evaluate the asymptotic tensor C*-norm of some elements in tensor product C*-algebras and to show semi-invertibility of the non-invertible extension of $C^*_r(\mathbb F_2)$ considered by Haagerup and Thorbjornsen.

E. G. Drukarev, A. I. Mikhailov, I. A. Mikhailov, W. Scheid

We show that the high energy limit for the amplitude of the double electron capture to the bound state of the Coulomb field of a nucleus with emission of a single photon is determined by behavior of the wave function in the vicinity of the singular triple coalescence point.

D. Soriano, D. Jacob, J. J. Palacios

It is shown how unbound electron wave functions can be expanded in a suitably chosen localized basis sets for any desired range of energies. In particular, we focus on the use of gaussian basis sets, commonly used in first-principles codes. The possible usefulness of these basis sets in a first-principles description of field emission or scanning tunneling m

R. Di Stefano

Nearby masses can have a high probability of lensing stars in a distant background field. High-probability lensing, or mesolensing, can therefore be used to dramatically increase our knowledge of dark and dim objects in the solar neighborhood, where it can discover and study members of the local dark population (free-floating planets, low-mass dwarfs, white

Matthieu Tissier, Gilles Tarjus

We study the critical behavior and phase diagram of the $d$-dimensional random field O(N) model by means of the nonperturbative functional renormalization group approach presented in the preceding paper. We show that the dimensional reduction predictions, obtained from conventional perturbation theory, break down below a critical dimension $d_{DR}(N)$ and we

David A. Thilker, Luciana Bianchi, Gerhardt Meurer, Armando Gil de Paz

We have initiated a search for extended ultraviolet disk (XUV-disk) galaxies in the local universe. Herein, we compare GALEX UV and visible--NIR images of 189 nearby (D$<$40 Mpc) S0--Sm galaxies included in the GALEX Atlas of Nearby Galaxies and present the first catalogue of XUV-disk galaxies. We find that XUV-disk galaxies are surprisingly common but have

Baris I. Erkmen, Jeffrey H. Shapiro

The theory of ghost imaging is developed in a Gaussian-state framework that both encompasses prior work - on thermal-state and biphoton-state imagers - and provides a complete understanding of the boundary between classical and quantum behavior in such systems. The core of this analysis is the expression derived for the photocurrent-correlation image obtaine

F. Borondo, D. A. Wisniacki, E. G. Vergini, R. M. Benito

Unstable periodic orbits are known to originate scars on some eigenfunctions of classically chaotic systems through recurrences causing that some part of an initial distribution of quantum probability in its vicinity returns periodically close to the initial point. In the energy domain, these recurrences are seen to accumulate quantum density along the orbit

Mason A. Porter, Chiara Daraio, Ivan Szelengowicz, Eric B. Herbold

We use experiments, numerical simulations, and theoretical analysis to investigate the propagation of highly nonlinear solitary waves in periodic arrangements of dimer (two-mass) and trimer (three-mass) cell structures in one-dimensional granular lattices. To vary the composition of the fundamental periodic units in the granular chains, we utilize beads of d

Yuri N. Obukhov, Guillermo F. Rubilar

We develop a general approach, based on the Lagrange-Noether machinery, to the definition of invariant conserved currents for gravity theories with general coordinate and local Lorentz symmetries. In this framework, every vector field ξon spacetime generates, in any dimension n, for any Lagrangian of gravitational plus matter fields and for any (minimal or n

Gilles Tarjus, Matthieu Tissier

We have developed a nonperturbative functional renormalization group approach for random field models and related disordered systems for which, due to the existence of many metastable states, conventional perturbation theory often fails. The approach combines an exact renormalization group equation for the effective average action with a nonperturbative appr

Thomas Quella, Volker Schomerus, Thomas Creutzig

In this note we compute exact boundary spectra for D-instantons in sigma-models on the supergroup PSL(2|2). Our results are obtained through an explicit summation of the perturbative expansion for conformal dimensions to all orders in the curvature radius. The analysis exploits several remarkable properties of the perturbation series that arises from rescali

Yuri N. Obukhov, Guillermo F. Rubilar

Previously, we have developed a general method to construct invariant conserved currents and charges in gravitational theories with Lagrangians that are invariant under spacetime diffeomorphisms and local Lorentz transformations. This approach is now generalized to the case when the local Lorentz group is replaced by an arbitrary local gauge group. The parti

A. L. Barabanov

A model for ternary fission is discussed in which a third particle (alpha-particle) is emitted due to non-adiabatic change of the nuclear potential at neck rapture. An expression for energy and angular distribution of alpha-particles is proposed. It is shown that an interaction between spin of fissioning system and orbital momentum of alpha-particle (spin-or

Vladimir Y. Chernyak, Michael Chertkov, Sergey V. Malinin, Razvan Teodorescu

We study a stochastic many-body system maintained in an non-equilibrium steady state. Probability distribution functional of the time-integrated current and density is shown to attain a large-deviation form in the long-time asymptotics. The corresponding Current-Density Cramer Functional (CDCF) is explicitly derived for irreversible Langevin dynamics and dis

C. Laumann, A. Scardicchio, S. L. Sondhi

We study the diluted Ising ferromagnet on the Bethe lattice as a case study for the application of the cavity method to problems with Griffiths-McCoy singularities. Specifically, we are able to make much progress at infinite coupling where we compute, from the cavity method, the density of Lee-Yang zeroes in the paramagnetic Griffiths region as well as the p

Stephen M. Merkowitz, Philip W. Dabney, Jeffrey C. Livas, Jan F. McGarry

More precise lunar and Martian ranging will enable unprecedented tests of Einstein&#39;s theory of General Relativity and well as lunar and planetary science. NASA is currently planning several missions to return to the Moon, and it is natural to consider if precision laser ranging instruments should be included. New advanced retroreflector arrays at careful

David B. Henley, Robin L. Shelton

We present an analysis of a pair of Suzaku spectra of the soft X-ray background (SXRB), obtained from pointings on and off a nearby shadowing filament in the southern Galactic hemisphere. Because of the different Galactic column densities in the two pointing directions, the observed emission from the Galactic halo has a different shape in the two spectra. We

Grégory Benmenzer, Emmanuel Gobet, Céline Jérusalem

In this article we present a continuous time model for natural gas and crude oil future prices. Its main feature is the possibility to link both energies in the long term and in the short term. For each energy, the future returns are represented as the sum of volatility functions driven by motions. Under the risk neutral probability, the motions of both ener

A. Trejo, Luis F. Rodriguez

We report sensitive VLA 3.6 cm radio observations toward the head of the Cone nebula in NGC 2264, made in 2006. The purpose of these observations was to study a non-thermal radio jet recently discovered, that appears to emanate from the head of the Cone nebula. The jet is highly polarized, with well-defined knots, and one-sided. The comparison of our images

M. Diehl, D. Yu. Ivanov

A number of hard exclusive scattering processes can be described in terms of generalized parton distributions (GPDs) and perturbative hard-scattering kernels. Both the physical amplitude and the hard-scattering kernels fulfill dispersion relations. We show that their consistency at all orders in perturbation theory is guaranteed if the GPDs satisfy certain i