August 2008 arXiv papers — page 2

Marek Zukowski

It is shown here that Suarez [Found. Phys. 38, 583 (2008)] wrongly presents the assumptions behind the Leggett's inequalities, and their modified form used by Groeblacher et al. [Nature 446, 871 (2007)] for an experimental falsification of a certain class of non-local hidden variable models.

Daniel E. Lucani, Muriel Médard, Milica Stojanovic

The goal of this paper is two-fold. First, to establish a tractable model for the underwater acoustic channel useful for network optimization in terms of convexity. Second, to propose a network coding based lower bound for transmission power in underwater acoustic networks, and compare this bound to the performance of several network layer schemes. The under

Samuel Tardif, Ing-Song Yu, Thibault Devillers, Mathieu Jamet

While achieving high Curie temperatures (above room temperature) in diluted magnetic semiconductors remains a challenge in the case of well controlled homogeneous alloys, several systems characterized by a strongly inhomogeneous incorporation of the magnetic component appear as promising. Incorporation of manganese into germanium drastically alters the growt

Jean-Guillaume Dumas, Laurent Fousse, Bruno Salvy

We present algorithms to perform modular polynomial multiplication or modular dot product efficiently in a single machine word. We pack polynomials into integers and perform several modular operations with machine integer or floating point arithmetic. The modular polynomials are converted into integers using Kronecker substitution (evaluation at a sufficient

Sk. Safique Ahmad, Nagalinga Rajan, Soumyendu Raha

To analyze the stability of Itô stochastic differential equations with multiplicative noise, we introduce the stochastic logarithmic norm. The logarithmic norm was originally introduced by G. Dahlquist in 1958 as a tool to study the growth of solutions to ordinary differential equations and for estimating the error growth in discretization methods for their

Pawel Stasiak, Michel J. P. Gingras

The LiHo$_x$Y$_{1-x}$F$_4$ Ising magnetic material subject to a magnetic field, $B_x$, perpendicular to the Ho$^{3+}$ Ising direction has shown over the past twenty years to be a host of very interesting thermodynamic and magnetic phenomena. Unfortunately, the availability of other magnetic materials other than LiHo$_x$Y$_{1-x}$F$_4$ that may be described by

Yu. I. Yermolaev, M. Yu. Yermolaev

Recently Zhang et al. [2008] presented a statistical study of sizes and relative geoeffectiveness of ICMEs (bodies of magnetic clouds) and preceding sheaths for 46 events responsible for intense (Dst < -100 nT) geomagnetic storms in 1996-2005 in which only a single ICME was responsible for generating the storm. Here we would like to comment several results a

O. B. Slee, H. Andernach, V. J. McIntyre, G. S. Tsarevsky

The Australia Telescope Compact Array (ATCA) has been used at 1.38 and 2.38 GHz to survey seven southern Abell clusters of galaxies with high X-ray luminosities: A2746, A2837, A3126, A3216, A3230, A3827 and A3836. The clusters have also been surveyed at 0.843 GHz with the Molonglo Observatory Synthesis Telescope (MOST). We have listed a complete 1.38-GHz sam

J. Q. You, Xiao-Feng Shi, Franco Nori

Using superconducting quantum circuits, we propose an approach to construct a Kitaev lattice, i.e., an anisotropic spin model on a honeycomb lattice with three types of nearest-neighbor interactions. We study two particular cases to demonstrate topological states (i.e., the vortex and bond states) and show how the braiding statistics can be revealed. Our app

Masanori Iye

A brief overview on the current status of the census of the early universe population is given. Observational surveys of high redshift galaxies provide direct opportunities to witness the cosmic dawn and to have better understanding of how and when infant galaxies evolve into mature ones. It is a much more astronomical approach in contrast to the physical ap

Si Xie

A model-independent global search for new physics has been performed at the CDF experiment. This search examines 399 final states, looking for discrepancies between observation and the standard model expectation in populations, kinematic shapes, bumps in mass distributions suggestive of new resonances and the tails of the summed transverse momentum distribut

Tomohiro Koyama, Gen Yamada, Hironobu Tanigawa, Shinya Kasai

We report the direct observation of the current-driven domain wall (DW) motion by magnetic force microscopy in a structured Co/Ni wire with perpendicular magnetic anisotropy. The wire has notches to define the DW position. It is demonstrated that single current pulses can precisely control the DW position from notch to notch with high DW velocity of 40 m/s.

De-Xing Kong, Kefeng Liu, Ming Shen

In this letter we construct a new time-periodic solution of the vacuum Einstein&#39;s field equations whose Riemann curvature norm takes the infinity at some points. We show that this solution is intrinsically time-periodic and describes a time-periodic universe with the &#34;black hole&#34;. New physical phenomena are investigated and new singularities are

Mark L. Henle, Brian DiDonna, Christian D. Santangelo, Ajay Gopinathan

Describing the diffusion of particles through crowded, confined environments with which they can interact is of considerable biological and technological interest. Under conditions where the confinement dimensions become comparable to the particle dimensions, steric interactions between particles, as well as particle-wall interactions, will play a crucial ro

Takashi Hotta

By employing a numerical renormalization group technique, we evaluate electronic specific heat coefficient $γ$ of the Anderson model coupled with local anharmonic phonons for the oscillation of a caged atom. For the rattling-type cage potential with a flat and wide region in the bottom, we find that phonon-mediated attraction is largely enhanced. When the po

Won Sang Cho, Yeong Gyun Kim, Chan Beom Park

We show that $Z$ polarization measurement is useful for distinguishing the signal decay chain of the `golden region&#39; in the minimal supersymmetric standard model(MSSM) parameter space, which involves the stop decay of $\tilde t_2 \to \tilde t_1 + Z$, from other decay chains involving the neutralino decay of $\tildeχ_2^0 \to \tildeχ_1^0 + Z$ in different

Lei Zhang, Matthew Gilbert, Jesper Pedersen, John Shumway

We explore exchange coupling of a pair of spins in a double dot and in an optical lattice. Our algorithm uses the frequency of exchanges in a bosonic path integral, evaluated with Monte Carlo. This algorithm is simple enough to be a &#34;black box&#34; calculator, yet gives insights into the role of correlation through two-particle probability densities, vis

David Carlton, Nathan Emley, Eduard Tuchfeld, Jeffrey Bokor

We report a simulation study on interacting ensembles of Co nanomagnets that can perform basic logic operations and propagate logic signals, where the state variable is the magnetization direction. Dipole field coupling between individual nanomagnets drives the logic functionality of the ensemble and coordinated arrangements of the nanomagnets allow for the

Keith R. Dienes, Michael Lennek

In light of recent discussions of the string landscape, it is essential to understand the degree to which string theory is predictive. We argue that it is unlikely that the landscape as a whole will exhibit unique correlations amongst low-energy observables, but rather that different regions of the landscape will exhibit different overlapping sets of correla

D. D. Lin, T. J. Lim

We propose a unified framework for deriving and studying soft-in-soft-out (SISO) detection in interference channels using the concept of variational inference. The proposed framework may be used in multiple-access interference (MAI), inter-symbol interference (ISI), and multiple-input multiple-outpu (MIMO) channels. Without loss of generality, we will focus

Lucas A. Cieza, Jonathan J. Swift, Geoffrey S. Mathews, Jonathan P. Williams

We report deep Sub-Millimeter Array observations of 26 pre-main-sequence (PMS) stars with evolved inner disks. These observations measure the mass of the outer disk (r ~20-100 AU) across every stage of the dissipation of the inner disk (r < 10 AU) as determined by the IR spectral energy distributions (SEDs). We find that only targets with high mid-IR excesse

Linda M. Carpenter

I propose implementing General Gauge Mediation using the class of $SU(N) \times U(1)$ SUSY breaking models. As an existence proof, I have utilized the 4-1 model in building multi-parameter gauge mediation. These hidden sectors are relatively easy to use and avoid several model building pitfalls such as runaway directions. In addition models require no specia

M. Ajello, P. Rebusco, N. Cappelluti, O. Reimer

We report about the detection of 10 clusters of galaxies in the ongoing Swift/BAT all-sky survey. This sample, which comprises mostly merging clusters, was serendipitously detected in the 15--55 keV band. We use the BAT sample to investigate the presence of excess hard X-rays above the thermal emission. The BAT clusters do not show significant (e.g. >2 $σ$)

V. Mathai, R. B. Melrose, I. M. Singer

An index theory for projective families of elliptic pseudodifferential operators is developed when the twisting, i.e. Dixmier-Douady, class is decomposable. One of the features of this special case is that the corresponding Azumaya bundle can be realized in terms of smoothing operators. The topological and the analytic index of a projective family of ellipti

Davide Pietrobon, Alexandre Amblard, Amedeo Balbi, Paolo Cabella

We apply spherical needlets to the Wilkinson Microwave Anisotropy Probe 5-year cosmic microwave background (CMB) dataset, to search for imprints of non-isotropic features in the CMB sky. We use the needlets localization properties to resolve peculiar features in the CMB sky and to study how these features contribute to the anisotropy power spectrum of the CM

L. Cywinski, W. M. Witzel, S. Das Sarma

We investigate pure dephasing decoherence (free induction decay and spin echo) of a spin qubit interacting with a nuclear spin bath. While for infinite magnetic field B the only decoherence mechanism is spectral diffusion due to dipolar flip-flops of nuclear spins, with decreasing B the hyperfine-mediated interactions between the nuclear spins become importa

Anders J. Frankild, Sean Sather-Wagstaff, Amelia Taylor

We investigate Buchbaum and Eisenbud&#39;s construction of the second symmetric power S^2_R(X) of a chain complex X of modules over a commutative ring R. We state and prove a number of results from the folklore of the subject for which we know of no good direct references. We also provide several explicit computations and examples. We use this construction t

Steven Weber, Jeffrey G. Andrews, Nihar Jindal

This paper surveys and unifies a number of recent contributions that have collectively developed a metric for decentralized wireless network analysis known as transmission capacity. Although it is notoriously difficult to derive general end-to-end capacity results for multi-terminal or \adhoc networks, the transmission capacity (TC) framework allows for quan

Soummya Kar, Jose M. F. Moura, Kavita Ramanan

The paper studies distributed static parameter (vector) estimation in sensor networks with nonlinear observation models and noisy inter-sensor communication. It introduces \emph{separably estimable} observation models that generalize the observability condition in linear centralized estimation to nonlinear distributed estimation. It studies two distributed e

V. Salari, M. Rahnama, J. A. Tuszynski

The feasibility of wave function collapse in the human brain has been the subject of vigorous scientific debates since the advent of quantum theory. Scientists like Von Neumann, London, Bauer and Wigner (initially) believed that wave function collapse occurs in the brain or is caused by the mind of the observer. It is a legitimate question to ask how human b

Matthew D. Duez, Francois Foucart, Lawrence E. Kidder, Harald P. Pfeiffer

We present a code for solving the coupled Einstein-hydrodynamics equations to evolve relativistic, self-gravitating fluids. The Einstein field equations are solved in generalized harmonic coordinates on one grid using pseudospectral methods, while the fluids are evolved on another grid using shock-capturing finite difference or finite volume techniques. We s

Jonathan L. Feng, Jason Kumar, John Learned, Louis E. Strigari

We consider the prospects for testing the dark matter interpretation of the DAMA/LIBRA signal with the Super-Kamiokande experiment. The DAMA/LIBRA signal favors dark matter with low mass and high scattering cross section. We show that these characteristics imply that the scattering cross section that enters the DAMA/LIBRA event rate determines the annihilati

Frederick K. Lamb, Stratos Boutloukos, Sandor Van Wassenhove, Robert T. Chamberlain

We investigate further a model of the accreting millisecond X-ray pulsars we proposed earlier. In this model, the X-ray-emitting regions of these pulsars are near their spin axes but move. This is to be expected if the magnetic poles of these stars are close to their spin axes, so that accreting gas is channeled there. As the accretion rate and the structure

Kentaro Aoki, Tomonori Totani, Takashi Hattori, Kouji Ohta

We examine variability of absorption line strength of intervening systems along the line of sight to GRB 060206 at $z = 4.05$, by the low-resolution optical spectra obtained by the Subaru telescope from six to ten hours after the burst. Strong variabilities of Fe\emissiontype{II} and Mg\emissiontype{II} lines at $z=1.48$ during $t=$5--8 hours have been repor

Rudolf Hanel, Stefan Thurner

In statistical physics lately a specific kind of average, called the q-expectation value, has been extensively used in the context of q-generalized statistics dealing with distributions following power-laws. In this context q-expectation values appear naturally. After it has been recently shown that this non-linear functional is instable, under a very strong

Yosuke Imamura, Keisuke Kimura

We consider N=2 quiver Chern-Simons theories described by brane tilings, whose moduli spaces are toric Calabi-Yau 4-folds. Simple prescriptions to obtain toric data of the moduli space and a corresponding brane crystal from a brane tiling are proposed.

Shirin Jalali, Tsachy Weissman

We propose an approach to lossy source coding, utilizing ideas from Gibbs sampling, simulated annealing, and Markov Chain Monte Carlo (MCMC). The idea is to sample a reconstruction sequence from a Boltzmann distribution associated with an energy function that incorporates the distortion between the source and reconstruction, the compressibility of the recons

Emil T. Akhmedov, P. V. Buividovich

It is well known that there should be a total cancellation of the IR divergences in unitary interacting field theories, such as QED and gravity. The cancellation should be at all orders between loop and tree level contributions to cross--sections. This is the crucial fact related to the unitarity of the evolution operator (S--matrix) of the underlying intera

C. Ospelkaus, S. Ospelkaus

This PhD tutorial article is a review of our experiments on heteronuclear quantum gas mixtures at the University of Hamburg. We introduce basic properties of trapped Fermi-Bose mixtures and demonstrate the achievement of large quantum degenerate mixtures of 40K and 87Rb. Using heteronuclear Feshbach resonances, we show how the heteronuclear interaction can b

RadhaKrishna Ganti, Martin Haenggi

In a wireless network the set of transmitting nodes changes frequently because of the MAC scheduler and the traffic load. Previously, connectivity in wireless networks was analyzed using static geometric graphs, and as we show leads to an overly constrained design criterion. The dynamic nature of the transmitting set introduces additional randomness in a wir

E. E. Edwards, M. Beeler, Tao Hong, S. L. Rolston

We experimentally investigate the role of localization on the adiabaticity of loading a Bose-Einstein condensate into a one-dimensional optical potential comprised of a shallow primary lattice plus one or two perturbing lattice(s) of incommensurate period. We find that even a very weak perturbation causes dramatic changes in the momentum distribution and mak

D0 Collaboration, V. Abazov

We report the observation of the doubly strange b baryon Omega_b- in the decay channel Omega_b- to J/psi Omega-, with J/psi to mu+ mu- and Omega- to Lambda K-, in $p\bar{p}$ collisions at $\sqrt{s}=1.96$ TeV. Using approximately 1.3 fb$^{-1}$ of data collected with the D0 detector at the Fermilab Tevatron Collider, we observe 17.8 +/- 4.9 (stat) +/- 0.8 (sys

Silvano Garnerone, N. Tobias Jacobson, Stephan Haas, Paolo Zanardi

We study the random XY spin chain in a transverse field by analyzing the susceptibility of the ground state fidelity, numerically evaluated through a standard mapping of the model onto quasi-free fermions. It is found that the fidelity susceptibility and its scaling properties provide useful information about the phase diagram. In particular it is possible t

C. Aidala

A variety of measurements performed utilizing transversely polarized proton- proton collisions at the Relativistic Heavy Ion Collider (RHIC) are now avail- able. Recent results from the PHENIX and BRAHMS experiments are presented and discussed.

H. -Y. Yang, P. M. Ricker, P. M. Sutter

Using a hydrodynamics plus N-body simulation of galaxy cluster formation within a large volume and mock Chandra X-ray observations, we study the form and evolution of the intrinsic scatter about the best-fit X-ray temperature-mass relation for clusters. We investigate the physical origin of the scatter by correlating it with quantities that are closely relat

A. Marek, H. -Th. Janka, E. Mueller

We present 2D hydrodynamic simulations of the long-time accretion phase of a 15 solar mass star after core bounce and before the launch of a supernova explosion. Our simulations are performed with the Prometheus-Vertex code, employing multi-flavor, energy-dependent neutrino transport and an effective relativistic gravitational potential. Testing the influenc

Xiong-Jun Liu, Mario F. Borunda, Xin Liu, Jairo Sinova

We propose an experimental scheme to study spin-orbit coupling effects in a of two-dimensional (2D) Fermi atomic gas cloud by coupling its internal electronic states (pseudospins) to radiation in a delta configuration. The induced spin-orbit coupling can be of the Dresselhaus and Rashba type with and without a Zeeman term. We show that the optically induced

Ofer Shayevitz, Meir Feder

We address the problem of universal communications over an unknown channel with an instantaneous noiseless feedback, and show how rates corresponding to the empirical behavior of the channel can be attained, although no rate can be guaranteed in advance. First, we consider a discrete modulo-additive channel with alphabet $\mathcal{X}$, where the noise sequen

Daniel A. Spielman, Shang-Hua Teng

We introduce a new notion of graph sparsificaiton based on spectral similarity of graph Laplacians: spectral sparsification requires that the Laplacian quadratic form of the sparsifier approximate that of the original. This is equivalent to saying that the Laplacian of the sparsifier is a good preconditioner for the Laplacian of the original. We prove that e

Timothy Cohen, David E. Morrissey, Aaron Pierce

The properties of the dark matter that determine its thermal relic abundance can be very different from the dark matter properties today. We investigate this possibility by coupling a dark matter sector to a scalar that undergoes a phase transition after the dark matter freezes out. If the value of Omega_DM h^2 calculated from parameters measured at collider

Amit Kashi, Noam Soker

We propose an explanation to the puzzling appearance of a wide blue absorption wing in the He I 10830A P-Cygni profile of the massive binary star Eta Carinae several months before periastron passage. Our basic assumption is that the colliding winds region is responsible for the blue wing absorption. By fitting observations, we find that the maximum outflow v

Atsushi Taruya, Kazuya Koyama, Takahiko Matsubara

Employing the perturbative treatment of gravitational clustering, we discuss possible effects of primordial non-Gaussianity on the matter power spectrum. As gravitational clustering develops, the coupling between different Fourier modes of density perturbations becomes important and the primordial non-Gaussianity which intrinsically possesses a non-trivial m

Andrzej Sitarz

We propose the extension of the spectral action principle to fermions and show that the neutrino mass terms appear then naturally as next-order corrections.

Tomoyuki Yamakami

In formal language theory, one of the most fundamental tools, known as pumping lemmas, is extremely useful for regular and context-free languages. However, there are natural properties for which the pumping lemmas are of little use. One of such examples concerns a notion of advice, which depends only on the size of an underlying input. A standard pumping lem

M. Tahir, K. Sabeeh, A. MacKinnon

We present a theoretical study of magnetocapacitance in a graphene monolayer at finite temperature taking into account the effects of disorder. The density of states (DOS) and magnetocapacitance found for graphene are compared to those found in standard two dimensional electron gas (2DEG) systems. The magnetic oscillations in DOS and magnetocapacitance are f

Brendon LaBuz

In ``Rips complexes and covers in the uniform category&#39;&#39; the authors define, following James, covering maps of uniform spaces and introduce the concept of generalized uniform covering maps. Conditions for the existence of universal uniform covering maps and generalized uniform covering maps are given. This paper notes that the universal generalized u

Shaofang Hong, Raphael Loewy

In this paper we present systematically analysis on the smallest eigenvalue of matrices associated with completely even functions (mod $r$). We obtain several theorems on the asymptotic behavior of the smallest eigenvalue of matrices associated with completely even functions (mod $r$). In particular, we get information on the asymptotic behavior of the small

François Bavaud

Formalising the confrontation of opinions (models) to observations (data) is the task of Inferential Statistics. Information Theory provides us with a basic functional, the relative entropy (or Kullback-Leibler divergence), an asymmetrical measure of dissimilarity between the empirical and the theoretical distributions. The formal properties of the relative

Thomas M. Fiore, Simona Paoli

We construct a cofibrantly generated Quillen model structure on the category of small n-fold categories and prove that it is Quillen equivalent to the standard model structure on the category of simplicial sets. An n-fold functor is a weak equivalence if and only if the diagonal of its n-fold nerve is a weak equivalence of simplicial sets. This is an n-fold

Michele Caraglio, Ferdinando Gliozzi

The entanglement entropy of a subsystem of a quantum system is expressed, in the replica approach, through analytic continuation with respect to n of the trace of the n-th power of the reduced density matrix. This trace can be thought of as the vacuum expectation value of a suitable observable in a system made with n independent copies of the original system

Xiuqing Huang

Using the newly developed real space vortex-lattice based theory of superconductivity, we study the maximum superconducting transition temperature (T_{c}^{\max}) in the iron-based superconductors. We find that all the reported FeAs superconductors can be divided into two basic classes (c/a=3 and c/a=5/2) depending on the lattice constants, where a is the Fe-

P. Samuelsson, I. Neder, M. Buttiker

We present a theory for two-particle entanglement production and detection in mesoscopic conductors at finite temperature. In contrast to the zero temperature limit, the entanglement of the density matrix projected out of the emitted many-body state is different from the entanglement of the reduced density matrix, detectable by current correlation measuremen

Oliver Bültel

We give several new moduli interpretations of the fibers of certain Shimura varieties over several prime numbers. As a consequence (of our theorem 9.1) one obtains that for every prescribed odd prime characteristic $p$ every bounded symmetric domain possesses quotients by arithmetic groups whose models have good reduction at a prime divisor of $p$.

Amar Prakash Azad, Eitan Altman, R. El-Azouzi

The paper studies the routing in the network shared by several users. Each user seeks to optimize either its own performance or some combination between its own performance and that of other users, by controlling the routing of its given flow demand. We parameterize the degree of cooperation which allows to cover the fully non-cooperative behavior, the fully

Th. Maschberger, C. J. Clarke

We have made a new compilation of observations of maximum stellar mass versus cluster membership number from the literature, which we analyse for consistency with the predictions of a simple random drawing hypothesis for stellar mass selection in clusters. Previously, Weidner and Kroupa have suggested that the maximum stellar mass is lower, in low mass clust

Anupam Karmakar, Naveen Kumar, Gennady Shvets, Oleg Polomarov

A new quasi-neutral model describing the Weibel instability of a high-current relativistic beam propagating through a resistive plasma is developed. It treats beam electrons as kinetic particles, and ambient plasma as a non-relativistic fluid. For a finite-temperature beam, a new class of negative energy magneto-sound waves is identified, which can possess n

Manuel Perez-Victoria

We use Pade approximants to systematically approximate scalar unparticle propagators and their associated phase factors by a finite number of ordinary particles. This is possible for conformal dimensions 1<d<2, and also for d>2 if we add local terms. A small number of particles can, in some cases, mimic unparticle signals. We also discuss how the approximant

N. Olivi-Tran

The random close packing fraction in two dimensions is calculated exactly via the central limit theorem and the brownian motion with no gain between monodisperse disks.

Oliver Riordan, Nicholas Wormald

In this paper we study the diameter of the random graph $G(n,p)$, i.e., the the largest finite distance between two vertices, for a wide range of functions $p=p(n)$. For $p=\la/n$ with $\la>1$ constant, we give a simple proof of an essentially best possible result, with an $O_p(1)$ additive correction term. Using similar techniques, we establish 2-point conc

Marek Gierlinski, Chris Done, Kim Page

We build a simple model of the optical/UV emission from irradiation of the outer disc by the inner disc and coronal emission in black hole binaries. We apply this to the broadband Swift data from the outburst of the black hole binary XTE J1817--330 to confirm previous results that the optical/UV emission in the soft state is consistent with a reprocessing a

R. J. Mondragon, S. Zhou

In complex networks the rich nodes are the subset of nodes with high degree. These well connected nodes tend to dominate the organisation of the network&#39;s structure. In non-evolving networks, a reference network has been used to detect if the connectivity between the rich nodes is due to chance or caused by an unknown mechanism. Chance is represented as

M. Herrmann, V. Batteiger, S. Knünz, G. Saathoff

We demonstrate a method for precision spectroscopy on trapped ions in the limit of unresolved motional sidebands. By sympathetic cooling of a chain of crystallized ions we suppress adverse temperature variations induced by the spectroscopy laser that usually lead to a distorted line profle and obtain a Voigt profile with negligible distortions. We applied th

Andrei Agrachev

We prove the result stated in the title; it is equivalent to the existence of a regular point of the sub-Riemannian exponential mapping. We also prove that the metric is analytic on an open everywhere dense subset in the case of a complete real-analytic sub-Riemannian manifold.

Tomo Tanaka, Takashi Tamaki

We consider the possibility that the horizon area is expressed by the general area spectrum in loop quantum gravity and calculate the black hole entropy by counting the degrees of freedom in spin-network states related to its area. Although the general area spectrum has a complex expression, we succeeded in obtaining the result that the black hole entropy is

Michel Enock

Mimicking the von Neumann version of Kustermans and Vaes&#39; locally compact quantum groups, Franck Lesieur had introduced a notion of measured quantum groupoid, in the setting of von Neumann algebras. In this article, we suppose that the basis of the measured quantum groupoid is central; in that case, we prove that a specific sub-${\bf C}^*$ algebra is inv

Florentina Bunea

This paper investigates correct variable selection in finite samples via $\ell_1$ and $\ell_1+\ell_2$ type penalization schemes. The asymptotic consistency of variable selection immediately follows from this analysis. We focus on logistic and linear regression models. The following questions are central to our paper: given a level of confidence $1-δ$, under

Benjamin A. Burton

Many key algorithms in 3-manifold topology involve the enumeration of normal surfaces, which is based upon the double description method for finding the vertices of a convex polytope. Typically we are only interested in a small subset of these vertices, thus opening the way for substantial optimization. Here we give an account of the vertex enumeration probl

Michel Enock

Mimicking the von Neumann version of Kustermans and Vaes&#39; locally compact quantum groups, Franck Lesieur had introduced a notion of measured quantum groupoid, in the setting of von Neumann algebras. In a former article, the author had introduced the notion of actions, crossed-product, dual actions of a measured quantum groupoid: a biduality theorem for a

Matthias Schneider

We give existence results for simple closed curves with prescribed geodesic curvature on $S^{2}$, which correspond to periodic orbits of a charge in a magnetic field.

Aurélien Djament, Christine Vespa

We compute the stable homology of orthogonal and symplectic groups over a finite field k with coefficients coming from an usual endofunctor F of k-vector spaces (exterior, symmetric, divided powers...), that is, for all natural integer i, we compute the colimits of the vector spaces $H_i(O_{n,n}(k) ; F(k^{2n}))$ and $H_i(Sp_{2n}(k) ; F(k^{2n}))$. In this sit

Umberto Cannella, Riccardo Sturani

We apply the Effective Field Theory approach to General Relativity, introduced by Goldberger and Rothstein, to study point-like and string-like sources in the context of scalar-tensor theories of gravity. Within this framework we compute the classical energy-momentum tensor renormalization to first Post-Newtonian order or, in the case of extra scalar fields,

Shun-ichiro Koh

The onset mechanism of superfluidity is examined by taking the case of the capillary flow of liquid helium 4. In the capillary flow, a substantial fall of the shear viscosity has been observed in the normal phase (lambda point<T<3.7K). In this temperature region, under the strong influence of Bose statistics, the coherent many-body wave function grows to an

Steven G. Krantz

We study a positive reproducing kernel for holomorphic functions on a domain in a complex space. The technique is based on an idea of L. Hua. Applications are provided. These ideas were developed in another context (quantization of Kähler manifolds) by Berezin.

Youngsik Huh, Ryo Nikkuni

A generic immersion of a planar graph into the 2-space is said to be knotted if there does not exist a trivial embedding of the graph into the 3-space obtained by lifting the immersion with respect to the natural projection from the 3-space to the 2-space. In this paper we show that if a generic immersion of a planar graph is knotted then the number of doubl

Jaime Merino, B. J. Powell, Ross H. McKenzie

We investigate an effective Hamiltonian for Na0.5CoO2 that includes the electrostatic potential due to the ordered Na ions and strong electronic correlations. This model displays a subtle interplay between metallic and insulating phases and between charge and magnetic order. For realistic parameters, the model predicts an insulating phase with similarities t

Yoshihiro Iwata, Yoshizumi Inoue, Makoto Minowa

A simple resonance ionization mass spectrometer is built with a Quadrupole Mass Spectrometer (QMS) and two laser diodes aiming at trace analysis of potassium. The overall detection efficiency is estimated comparing the yields of resonance ionization and electron-impact ionization in the same QMS. A clear discrimination of $^{39}\rm K$, $^{40}\rm K$ and $^{41

F. Feng, J. P. Ma, Q. Wang

A new method is proposed to calculate wave functions in $k_T$-factorization in \cite{LiMi} as a comment about our paper \cite{FMW}. We point out that the results obtained with the method are in conflict with the translation invariance and depend on the chosen contours for loop-integrals. Therefore, the method is in principle unacceptable and the results with

Aaron Clauset, Sidney Redner

We present a quantitative model for the biological evolution of species body masses within large groups of related species, e.g., terrestrial mammals, in which body mass M evolves according to branching (speciation), multiplicative diffusion, and an extinction probability that increases logarithmically with mass. We describe this evolution in terms of a conv

L. Zhao, X. Chen, C. K. Ong

We have setup a simple field mapping measure system to describe graphically the 2D quasi-free-space electromagnetic wave in a parallel plate waveguide at the X-band frequencies. Our apparatus illustrates a potential application in characterizing the microwave absorbing materials. The visual demonstration about the physical process and quantitative measuremen

I. E. Anderson, J. D. Olson, L. Yang, S. A. Carter

Spin-cast all-inorganic nanoparticle solutions have been used to make a CdTe/CdSe solar cell with an efficiency of up to 2.8% without alumina or calcium buffer layers. The type of junction and non-selective nature of the contacts made to these devices is explored.

Pavel Gorodetsky, Emmanuel Tannenbaum

The two classic theories for the existence of sexual replication are that sex purges deleterious mutations from a population, and that sex allows a population to adapt more rapidly to changing environments. These two theories have often been presented as opposing explanations for the existence of sex. Here, we develop and analyze evolutionary models based on

Marcello Sega, Pietro Faccioli, Francesco Pederiva, Henri Orland

We consider the application of Kramers theory to the microscopic calculation of rates of conformational transitions of macromolecules. The main difficulty in such an approach is to locate the transition state in a huge configuration space. We present a method which identifies the transition state along the most probable reaction pathway. It is then possible

Edward H. Feng, Gavin E. Crooks

An unresolved problem in physics is how the thermodynamic arrow of time arises from an underlying time reversible dynamics. We contribute to this issue by developing a measure of time-symmetry breaking, and by using the work fluctuation relations, we determine the time asymmetry of recent single molecule RNA unfolding experiments. We define time asymmetry as

Joseph Y. Halpern, Rafael Pass

We develop a general game-theoretic framework for reasoning about strategic agents performing possibly costly computation. In this framework, many traditional game-theoretic results (such as the existence of a Nash equilibrium) no longer hold. Nevertheless, we can use the framework to provide psychologically appealing explanations to observed behavior in wel

Thorsten Ohl, Christian Speckner

We study the production of the heavy W&#39; and Z&#39; bosons in the three site higgsless model at the LHC. We focus on the s-channel production mode to estimate the prospects for measuring their suppressed couplings to standard model fermions.

M. C. Nucci, K. M. Tamizhmani

We present a method devised by Jacobi to derive Lagrangians of any second-order differential equation: it consists in finding a Jacobi Last Multiplier. We illustrate the easiness and the power of Jacobi&#39;s method by applying it to several equations and also a class of equations studied by Musielak with his own method [Musielak ZE, Standard and non-standar

Kendall Atkinson, David Chien, Olaf Hansen

An elliptic partial differential equation Lu=f with a zero Dirichlet boundary condition is converted to an equivalent elliptic equation on the unit ball. A spectral Galerkin method is applied to the reformulated problem, using multivariate polynomials as the approximants. For a smooth boundary and smooth problem parameter functions, the method is proven to c

Ling Long, Chris Kurth

In this paper we show two classes of noncongruence subgroups satisfy the so-called unbounded denominator property. In particular, we establish our conjecture in [KL08] which says that every type II noncongruence character group of Gamma^0(11) satisfies the unbounded denominator property.

N. E. Csima, R. E. Kottwitz

This paper gives a rather concrete description of the category Rep(G) for certain flat commutative affine group schemes G over a discrete valuation ring such that the general fiber of G is the multiplicative group.

Jakob Stix

Rational points in the boundary of a hyperbolic curve over a field with sufficiently nontrivial Kummer theory are the source for an abundance of sections of the fundamental group exact sequence. We follow and refine Nakamura&#39;s approach towards these boundary sections. For example, we obtain a weak anabelian theorem for hyperbolic genus 0 curves over quit