April 2008 arXiv papers — page 49

E. J. Doedel, B. W. Kooi, Yu. A. Kuznetsov, G. A. K. van Voorn

In Part I of this paper we discussed new methods for the numerical continuation of point-to-cycle connecting orbits in 3-dimensional autonomous ODE's using projection boundary conditions. In this second part we extend the method to the numerical continuation of cycle-to-cycle connecting orbits. In our approach, the projection boundary conditions near the

2 Collaboration, R. R. Akhmetshin, V. M. Aulchenko, V. Sh. Banzarov

The process e+ e- -> phi -> K+ K- has been studied with the CMD-2 detector using about 542 000 events detected in the center-of-mass energy range from 1.01 to 1.034 GeV. The systematic error of the cross section is estimated to be 2.2%. The phi(1020) meson parameters in the phi -> K+K- decay channel have been measured: sigma_0(phi-> K+K-) = 2016 +- 8 +- 44 n

I. Augustin, H. H. Gutbrod, D. Kraemer, K. Langanke

The project of the international Facility for Antiproton and Ion Research (FAIR), co-located to the GSI facility in Darmstadt, has been officially started on November 7, 2007. The current plans of the facility and the planned research program will be described. An investment of about 1 billion euro will permit new physics programs in the areas of low and med

Giovanni Bussi, Alessandro Laio, Michele Parrinello

In this paper we propose a new formalism to map history-dependent metadynamics in a Markovian process. We apply this formalism to a model Langevin dynamics and determine the equilibrium distribution of a collection of simulations. We demonstrate that the reconstructed free energy is an unbiased estimate of the underlying free energy and analytically derive a

Saurav Samanta

The representations of position and momentum operators of a planar phase space having both position and momentum noncommutativity are obtained. Using these representations the dynamics of a particle in a gravitational quantum well is studied to calculate the upper bounds of the noncommutative parameters.

Evgeny Korotyaev, Andrey Badanin

We consider the Schrödinger operator with a periodic potential on a quasi 1D continuous periodic model of armchair nanotubes in $\R^3$ in a uniform magnetic field (with amplitude $B\in \R$), which is parallel to the axis of the nanotube. The spectrum of this operator consists of an absolutely continuous part (spectral bands separated by gaps) plus an infinit

Amie Wilkinson

This is an expository article/encyclopedia entry explaining the history, techniques, and central results in the field of smooth ergodic theory.

George A. Baker, James P. Hague

We propose a model that extends the binary ``united we stand, divided we fall'' opinion dynamics of Sznajd-Weron to handle continuous and multi-state discrete opinions. Disagreement dynamics are often ignored in continuous extensions of the binary rules, so we make the most symmetric continuum extension of the binary model that can treat the conseque

Alberto Blasi, Dario Ferraro, Nicola Maggiore, Nicodemo Magnoli

In this paper we consider an abelian Chern-Simons theory with plane boundary and we show, following Symankiz's quite general approach, how the known results for edge states in the Laughlin series can be derived in a systematic way by the separability condition. Moreover we show that the conserved boundary currents find a natural and explicit interpretati

A. Cerioni, F. Finelli, A. Gruppuso

We study the spectral index of curvature perturbations for inflationary models where the driving scalar field is coupled to a relativistic fluid through a friction term $Γ$. We find that only a very small friction term - $Γ\ll H$, with H being the Hubble parameter during inflation - is allowed by observations, otherwise curvature fluctuations are generated w

L. C. G. Rogers, Fanyin Zhou

In earlier studies, the estimation of the volatility of a stock using information on the daily opening, closing, high and low prices has been developed; the additional information in the high and low prices can be incorporated to produce unbiased (or near-unbiased) estimators with substantially lower variance than the simple open--close estimator. This paper

Jonathan D. Slavin

The Complex of Local Interstellar Clouds (CLIC) is a relatively tight grouping of low density, warm, partially ionized clouds within about 15 pc of the Solar System. The Local Interstellar Cloud (LIC) is the cloud observed on most lines of sight and may be the cloud that immediately surrounds our Solar System, the properties of which set the outer boundary c

M. N. Achasov, ChengDong Fu, Xiaohu Mo, N. Yu. Muchnoi

This document contains a proposal of the BEPC-II collider beam energy calibration system (IHEP, Beijing). The system is based on Compton backscattering of carbon dioxide laser radiation, producing a beam of high energy photons. Their energy spectrum is then accurately measured by HPGe detector. The high-energy spectrum edge will allow to determine the averag

J. Theodore Cox, Edwin A. Perkins

We show that renormalized two-dimensional Lotka--Volterra models near criticality converge to a super-Brownian motion. This is used to establish long-term survival of a rare type for a range of parameter values near the voter model.

Peter G. Doyle, Dan Rockmore

The rising algebra is a subalgebra of the group algebra of the symmetric group S_n, gotten by lumping together permutations having the same number of rising sequences. This well-known algebra arises naturally when studying riffle shuffles. Here we introduce a number of other subalgebras that arise naturally when studying `ruffles', which are like riffles

V. Urpin, D. Konenkov

We study the efficiency of Joule heating in the crustal layers of young neutron stars. It is shown that dissipation of the magnetic field is highly inhomogeneous in the crust with much faster dissipation in relatively low density layers. In young neutron stars, the rate of Joule heating in the crust can exceed the standard luminosity of non-magnetic star and

Lingyu Wang, Michael Rowan-Robinson, Issei Yamamura, Hiroshi Shibai

We present a careful analysis of the point source detection limit of the AKARI All-Sky Survey in the WIDE-S 90 $μ$m band near the North Ecliptic Pole (NEP). Timeline Analysis is used to detect IRAS sources and then a conversion factor is derived to transform the peak timeline signal to the interpolated 90 $μ$m flux of a source. Combined with a robust noise m

Marianne Morillon

We work in set-theory without choice $\ZF$. Given a closed subset $F$ of $[0,1]^I$ which is a bounded subset of $\ell^1(I)$ ({\em resp.} such that $F \subseteq \ell^0(I)$), we show that the countable axiom of choice for finite subsets of $I$, ({\em resp.} the countable axiom of choice $\ACD$) implies that $F$ is compact. This enhances previous results where

Selcuk S. Bayin

In a recent article we have introduced Friedmann thermodynamics, where certain geometric parameters in Friedmann models are treated like their thermodynamic counterparts (temperature, entropy, Gibbs potential etc.). This model has the advantage of allowing us to determine the geometry of the universe by thermodynamic stability arguments. In this article we r

Eyob Delele Yirdaw

This paper derives Touchard's theorem from Euler's form for odd perfect numbers. It also fine-tunes Euler's form.

G. Lapenta, S. Ju

We propose an alternative implementation of preconditioning techniques for the solution of non-linear problems. Within the framework of Newton-Krylov methods, preconditioning techniques are needed to improve the performance of the solvers. We propose a different implementation approach to re-utilize existing semi-implicit methods to precondition fully implic

R. J. H. Dunn, R. P. Fender, E. G. Koerding, C. Cabanac

We report on a comprehensive and consistent investigation into the X-ray emission from GX 339-4. All public observations in the 11 year RXTE archive were analysed. Three different types of model - single powerlaw, broken powerlaw and a disc + powerlaw - were fitted to investigate the evolution of the disc, along with a fixed gaussian component at 6.4 keV to

Kalobaran Maiti

We investigate the influence of impurities and vacancies in the formation of magnetic moment in CaB6 using full potential ab initio band structure calculations. CaB6 is found to be a band insulator with a band gap of about 0.2 eV. The calculated results indicate that carbon and oxygen substitution in boron sublattice, usually expected as impurity in low puri

A. E. Koshelev

Intrinsic Josephson-junction stacks realized in high-temperature superconductors provide a very attractive base for developing coherent sources of electromagnetic radiation in the terahertz frequency range. A promising way to synchronize phase oscillations in all the junctions is to excite an internal cavity resonance. We demonstrate that this resonance prom

Antoine Julien

We consider a subclass of tilings, the tilings obtained by cut and projection. Under somewhat standard assumptions, we show that the natural complexity function has polynomial growth. We compute its exponent αin terms of the ranks of certain groups which appear in the construction. We give bounds for α. These computations apply to some well known tilings, su

Benoît Lemaire, Guy Denhière

A computational model of the construction of word meaning through exposure to texts is built in order to simulate the effects of co-occurrence values on word semantic similarities, paragraph by paragraph. Semantic similarity is here viewed as association. It turns out that the similarity between two words W1 and W2 strongly increases with a co-occurrence, de

J. H. Jefferson, A. Ramsak, T. Rejec

A shallow potential well in a near-perfect quantum wire will bind a single-electron and behave like a quantum dot, giving rise to spin-dependent resonances of propagating electrons due to Coulomb repulsion and Pauli blocking. It is shown how this may be used to generate full entanglement between static and flying spin-qubits near resonance in a two-electron

K. Morawetz, P. Lipavsky, J. J. Mares

The effect of the magnetic field on a capacitor with a superconducting electrode is studied within the Ginzburg-Landau approach. It is shown that the capacitance has a discontinuity at the onset of the surface superconductivity $B_{\rm c3}$ which is expressed as a discontinuity in the penetration depth of the electric field into metals. Estimates show that t

Oskar Sandberg

We study a one parameter family of random graph models that spans a continuum between traditional random graphs of the Erdős-Rényi type, where there is no underlying structure, and percolation models, where the possible edges are dictated exactly by a geometry. We find that previously developed theories in the fields of random graphs and percolation have, st

Tomasz Ciszkowski, Charlott Eliasson, Markus Fiedler, Zbigniew Kotulski

The Voice over Internet Protocol (VoIP) is becoming a more available and popular way of communicating for Internet users. This also applies to Peer-to-Peer (P2P) systems and merging these two have already proven to be successful (e.g. Skype). Even the existing standards of VoIP provide an assurance of security and Quality of Service (QoS), however, these fea

S. Leon, L. Verdes-Montenegro, J. Sabater, D. Espada

The study of the radio properties of the AMIGA sample is intended to characterize the radio continuum emission for a sample least affected by local environment, thus providing a reference against which less isolated and interacting samples can be compared. Radio continuum data at 325, 1420 and 4850 MHz were extracted from the WENSS, NVSS/FIRST and GB6 survey

De-You Chen, Qing-Quan Jiang, Xiao-Tao Zu

Hawking radiation from black hole horizon can be viewed as a quantum tunnelling process, and fermions via tunnelling can successfully recover Hawking temperature. In this paper, considering the tunnelling particles with spin 1/2 (namely, Dirac particles), we further improve Kerner and Man's fermion tunnelling method to study Hawking radiation via tunnell

S. Peru, H. Goutte

Fully consistent axially-symmetric-deformed Quasi-particle Random Phase Approximation (QRPA) calculations have been performed, in which the same Gogny D1S effective force has been used for both the Hartree-Fock-Bogolyubov mean field and the QRPA approaches. Giant resonances calculated in deformed $^{26-28}$Si and $^{22-24}$Mg nuclei as well as in the spheric

V. Millot, A. Pisante

We classify nonconstant entire local minimizers of the standard Ginzburg-Landau functional for maps in $H^{1}_{loc}(R^3;R^3)$ satisfying a natural energy bound. Up to translations and rotations, such solutions of the Ginzburg-Landau system are given by an explicit solution equivariant under the action of the orthogonal group.

Johannes Leitner

In an incomplete Brownian-motion market setting, we propose a convex monotonic pricing functional for nonattainable bounded contingent claims which is compatible with prices for attainable claims. The pricing functional is defined as the convex conjugate of a generalized entropy penalty functional and an interpretation in terms of tracking with instantaneous

O. Esquivel, B. Fuchs

Following a wave-mechanical treatment we calculate the drag force exerted by an infinite homogeneous background of stars on a perturber as this makes its way through the system. We recover Chandrasekhar's classical dynamical friction (DF) law with a modified Coulomb logarithm. We take into account a range of models that encompasses all plausible density

H. -R. Müller, V. Florinski, J. Heerikhuisen, V. V. Izmodenov

Modeling of the global heliosphere seeks to investigate the interaction of the solar wind with the partially ionized local interstellar medium. Models that treat neutral hydrogen self-consistently and in great detail, together with the plasma, but that neglect magnetic fields, constitute a sub-category within global heliospheric models. There are several dif

Marco Fabbrichesi, Maurizio Piai, Luca Vecchi

We study a modification of the five-dimensional description of dynamical electro-weak symmetry breaking inspired by the AdS/CFT correspondence. Conformal symmetry is broken in the low-energy region near the IR brane by a power-law departure from the pure AdS background. Such a modification--while not spoiling the identification of the IR brane with the scale

Andreas Poppe, Momtchil Peev, Oliver Maurhart

A Quantum Key Distribution (QKD) network is currently implemented in Vienna by integrating seven QKD-Link devices that connect five subsidiaries of SIEMENS Austria. We give an architectural overview of the network and present the enabling QKD-technologies, as well as the novel QKD network protocols.

Carlos M. Mora, Rolando Rebolledo

The paper is devoted to the study of nonlinear stochastic Schrödinger equations driven by standard cylindrical Brownian motions (NSSEs) arising from the unraveling of quantum master equations. Under the Born--Markov approximations, this class of stochastic evolutions equations on Hilbert spaces provides characterizations of both continuous quantum measuremen

S. N. Fedotkin, A. G. Magner, M. Brack

We derive stability traces of bifurcating orbits in Hénon-Heiles potentials near their saddles

A. E. Mironov

In this work, we construct commutative rings of two variable matrix differential operators that are isomorphic to a ring of meromorphic functions on a rational manifold obtained from the $CP^1\times CP^1$ by identification of two lines with the pole on a certain rational curve.

A. E. Mironov

In this work, we find spectral data that allow to find Hamiltonian-minimal Lagrangian tori in $CP^2$ in terms of theta functions of spectral curves.

Paweł Sztonyk

Estimates of densities of convolution semigroups of probability measures are given under specific assumptions on the corresponding Lévy measure and the Lévy--Khinchin exponent. The assumptions are satisfied, e.g., by tempered stable semigroups of J. Rosi{ń}ski.

Melissa L. Macasieb, Thomas W. Mattman

Let K be a hyperbolic (-2,3,n) pretzel knot and M = S^3 K its complement. For these knots, we verify a conjecture of Reid and Walsh: there are at most three knot complements in the commensurability class of M. Indeed, if n \neq 7, we show that M is the unique knot complement in its class. We include examples to illustrate how our methods apply to a broad cla

K. Tatematsu, R. Kandori, T. Umemoto, Y. Sekimoto

The ``integral-shaped filament'' of the Orion A giant molecular cloud was mapped in N2H+, and its northern end, the OMC-2/3 region was observed also in HC3N and CCS. The N2H+ distribution is similar to the dust continuum distribution, except for the central part of the Orion Nebula. The distribution of H13CO+ holds resemblance to that of dust continu

Christian Thiemann, Martin Treiber, Arne Kesting

The NGSIM trajectory data sets provide longitudinal and lateral positional information for all vehicles in certain spatiotemporal regions. Velocity and acceleration information cannot be extracted directly since the noise in the NGSIM positional information is greatly increased by the necessary numerical differentiations. We propose a smoothing algorithm for

A. V. Kisselev, V. A. Petrov

In this paper we present an analysis of the multiple hadron production induced by primary heavy quarks in e+e- annihilation with the account of most complete and corrected experimental data. In the framework of perturbative QCD, new theoretical bounds on the asymptotically constant differences of the multiplicities in processes with light and heavy quarks ar

Patrick Wils, Stelios Kleidis, Eric Broens

The Blazhko effect in RR Lyrae stars is still poorly understood theoretically. Stars with multiple Blazhko periods or in which the Blazhko effect itself varies are particularly challenging. This study investigates the Blazhko effect in the RRc star LS Her. Detailed VRI CCD photometry has been performed on 63 nights during six months. LS Her is confirmed to h

Andrey Feuerverger

Rejoinder of ``Statistical analysis of an archeological find'' [arXiv:0804.0079]

Joseph B. Kadane

Discussion of ``Statistical analysis of an archeological find'' by Andrey Feuerverger [arXiv:0804.0079]

Edoardo Ballico, Francesco Malaspina

Here we consider the product of varieties with $n$-blocks collections . We give some cohomological splitting conditions for rank 2 bundles. A cohomological characterization for vector bundles is also provided. The tools are Beilinson's type spectral sequences generalized by Costa and Miró-Roig. Moreover we introduce a notion of Castelnuovo-Mumford regula

J. Mortera, P. Vicard

Discussion of ``Statistical analysis of an archeological find'' by Andrey Feuerverger [arXiv:0804.0079]

Edoardo Ballico, Francesco Malaspina

Let $f_s: X_s \to {\bf {P}}^2$ be the blowing-up of $s$ distinct points and $E$ a vector bundle on $X_s$. Here we give a cohomological criterio which is equivalent to $E \cong f_s^\ast (A)$ with $A$ a direct sum of line bundles. We also some cohomological characterizations of very particular rank 2 vector bundles on ${\bf {P}}^2$.

Randall Ingermanson

We critique the analysis by A. Feuerverger of an archaeological find [arXiv:0804.0079] that has been alleged by some to be the tomb of Jesus of Nazareth. We show that his analysis rests on six faulty assumptions that have been severely criticized by historians, archaeologists, and scholars in related disciplines. We summarize the results of an alternative co

Koong Chee Weng, N. Chandrasekhar, Christian Miniatura, Berthold-Georg Englert

Hirsch (1999) proposed a mechanism and geometry for the observation of the spin-Hall effect. In this work, we present a novel realization of the Hirsch geometry in a platinum (Pt) nanostructure, which is an increasingly important material for spintronics applications. Measurements were made in a non-local geometry to avoid spurious effects. The measurements

Holger Höfling, Larry Wasserman

Discussion of ``Statistical analysis of an archeological find'' by Andrey Feuerverger [arXiv:0804.0079]

Sheila M. Bird

Discussion of ``Statistical analysis of an archeological find'' by Andrey Feuerverger [arXiv:0804.0079]

Michael W. Feast

Adopting a distance for RS Pup derived from a period-luminosity relation based on Cepheid parallaxes, it is shown that the phase-lag observations of the surrounding nebulosity by Kervella et al. are well fitted by a model of an equatorial disc at an angle of 8.1 $\pm$ 0.6 degrees to the plane of the sky. The astrophysical implications of this are briefly men

A. E. Mironov, Dafeng Zuo

In this paper by reduction we construct a family of conformally flat Hamiltonian-minimal Lagrangian tori in $\mathbb{CP}^3$ as the image of the composition of the Hopf map $\mathcal{H}: \mathbb{S}^7\to \mathbb{CP}^3$ and a map $ψ:\mathbb{R}^3 \to \mathbb{S}^7$ with certain conditions.

Donald L. Bentley

Discussion of ``Statistical analysis of an archeological find'' by Andrey Feuerverger [arXiv:0804.0079]

E. Ostrovsky, L. Sirota

We have introduced and investigated so-called Shlomilchs and Bells series for modified Bessel's functions, namely, their asymptotic and non-asymptotic properties, connection with Stirling's and Bell's numbers etc. We have obtained exact constants in the moment inequalities for sums of centered independent random variables, improved their asymptot

Camil Fuchs

Discussion of ``Statistical analysis of an archeological find'' by Andrey Feuerverger [arXiv:0804.0079]

Ryo Okamoto, Holger F. Hofmann, Tomohisa Nagata, Jeremy L. O'Brien

Quantum metrology promises greater sensitivity for optical phase measurements than could ever be achieved classically. Here we present a theory of the phase sensitivity for the general case where the detection probability is given by an $N$ photon interference fringe. We find that the phase sensitivity has a complex dependence on both the intrinsic efficienc

A. Barchielli, M. Gregoratti, M. Licciardo

We consider a two-level atom stimulated by a coherent monochromatic laser and we study how to enhance the squeezing of the fluorescence light and of the atom itself in the presence of a Wiseman-Milburn feedback mechanism, based on the homodyne detection of a fraction of the emitted light. Besides analyzing the effect of the control parameters on the squeezin

D. V. Shirkov

In quantum theory, physical amplitudes are usually presented in the form of Feynman perturbation series in powers of coupling constant $\al .$ However, it is known that these amplitudes are not regular functions at $α=0 .$ For QCD, we propose new sets of expansion parameters ${\bf w}_k(\as)$ that reflect singularity at $\as=0 $ and should be used instead of

T. Monz, K. Kim, W. Hänsel, M. Riebe

Algorithms for quantum information processing are usually decomposed into sequences of quantum gate operations, most often realized with single- and two- qubit gates[1]. While such operations constitute a universal set for quantum computation, gates acting on more than two qubits can simplify the implementation of complex quantum algorithms[2]. Thus, a singl

Stephen M. Stigler

Discussion of ``Statistical analysis of an archeological find'' by Andrey Feuerverger [arXiv:0804.0079]

Andrey Feuerverger

In 1980, a burial tomb was unearthed in Jerusalem containing ossuaries (limestone coffins) bearing such inscriptions as Yeshua son of Yehosef, Marya, Yoseh--names which match those of New Testament (NT) figures, but were otherwise in common use. This paper discusses certain statistical aspects of authenticating or repudiating links between this find and the

A. Rawat, Francois Hammer, Ajit K. Kembhavi, Hector Flores

We use a combination of deep, high angular resolution imaging data from the CDFS (HST/ACS GOODS survey) and ground based near-IR $K_s$ images to derive the evolution of the galaxy major merger rate in the redshift range $0.2 \leq z \leq 1.2$. We select galaxies on the sole basis of their J-band rest-frame, absolute magnitude, which is a good tracer of the st

Takayuki Tamura, Kazuhisa Mitsuda, Yoh Takei, Noriko Y. Yamasaki

The results from Suzaku XIS observations of the relaxed cluster of galaxies Abell2052 are presented. Offset pointing data are used to estimate the Galactic foreground emission in the direction to the cluster. Significant soft X-ray excess emission above this foreground, the intra-cluster medium emission, and other background components is confirmed and resol

Yuki Fuseya, Masao Ogata, Hidetoshi Fukuyama

Hall effects are investigated for three-dimensional Dirac electrons as a model of bismuth alloys. It is found that there is unconventional contributions to the Hall conductivity $σ_{xy}$ generated by the interband effects of a magnetic field. This phenomena is remarkable near the band-edge. The Hall coefficient exhibits two unexpected properties; a sharp pea

Jaap-Henk Hoepman

Private handshaking allows pairs of users to determine which (secret) groups they are both a member of. Group membership is kept secret to everybody else. Private handshaking is a more private form of secret handshaking, because it does not allow the group administrator to trace users. We extend the original definition of a handshaking protocol to allow and

Erlin Yao

Mafia can be described as an experiment in human psychology and mass hysteria, or as a game between informed minority and uninformed majority. Focus on a very restricted setting, Mossel et al. [to appear in Ann. Appl. Probab. Volume 18, Number 2] showed that in the mafia game without detectives, if the civilians and mafias both adopt the optimal randomized s

M. Malik, J. Dey, Meheboob Alam

Linear stability and the non-modal transient energy growth in compressible plane Couette flow are investigated for two prototype mean flows: (a) the {\it uniform shear} flow with constant viscosity, and (b) the {\it non-uniform shear} flow with {\it stratified} viscosity. Both mean flows are linearly unstable for a range of supersonic Mach numbers ($M$). For

Y. Suzuki, W. Horiuchi, M. Orabi, K. Arai

The angular motion of a few-body system is described with global vectors which depend on the positions of the particles. The previous study using a single global vector is extended to make it possible to describe both natural and unnatural parity states. Numerical examples include three- and four-nucleon systems interacting via nucleon-nucleon potentials of

Kevin Henshall, Peter Schachte, Harald Søndergaard, Leigh Whiting

Selman and Kautz's work on ``knowledge compilation'' established how approximation (strengthening and/or weakening) of a propositional knowledge-base can be used to speed up query processing, at the expense of completeness. In this classical approach, querying uses Horn over- and under-approximations of a given knowledge-base, which is represente

M. Malik, Meheboob Alam, J. Dey

Nonmodal transient growth studies and estimation of optimal perturbations have been made for the compressible plane Couette flow with three-dimensional disturbances. The maximum amplification of perturbation energy over time, $G_{\max}$, is found to increase with increasing Reynolds number ${\it Re}$, but decreases with increasing Mach number $M$. More speci

Peter Moeck

Two novel (and proprietary) strategies for the structural identification of a nanocrystal from either a single high-resolution (HR) transmission electron microscopy (TEM) image or a single precession electron diffraction pattern are proposed and their advantages discussed in comparison to structural fingerprinting from powder X-ray diffraction patterns. Simu

Chen-Lung Hung, Xibo Zhang, Nathan Gemelke, Cheng Chin

We demonstrate a simple scheme to achieve fast, runaway evaporative cooling of optically trapped atoms by tilting the optical potential with a magnetic field gradient. Runaway evaporation is possible in this trap geometry due to the weak dependence of vibration frequencies on trap depth, which preserves atomic density during the evaporation process. Using th

Lucien Hardy

We expect a theory of Quantum Gravity to be both probabilistic and have indefinite causal structure. Indefinite causal structure poses particular problems for theory formulation since many of the core ideas used in the usual approaches to theory construction depend on having definite causal structure. For example, the notion of a state across space evolving

Nick Letzepis, Albert Guillen i Fabregas

The free-space optical channel has the potential to facilitate inexpensive, wireless communication with fiber-like bandwidth under short deployment timelines. However, atmospheric effects can significantly degrade the reliability of a free-space optical link. In particular, atmospheric turbulence causes random fluctuations in the irradiance of the received l

Dastgeer Shaikh

We develop a self-consistent model of turbulence in a local interstellar medium (ISM). The model describes a partially ionized magnetofluid ISM in which a neutral hydrogen fluid interacts with a plasma dominantly through a charge exchange. The ISM turbulent correlation scales in our model are much bigger than the shock characteristic length-scales. Unlike sm

A. C. Mafra, B. Scardua

We prove that a one-dimensional foliation with generic singularities on a projective space, exhibiting a Lie group transverse structure in the complement of some codimension one algebraic subset is logarithmic, i.e., it is the intersection of codimension one foliations given by closed one-forms with simple poles. If there is only one singularity in a suitabl

V. G. Eselevich, V. M. Bogod, I. V. Chashey, M. V. Eselevich

Recently Tsurutani et al., (2008) (Paper 1) analyzed the complex interplanetary structures during 7 to 8 November, 2004 to identify their properties as well as resultant geomagnetic effects and the solar origins. Besides mentioned paper by Gopalswamy et al., (2006) the solar and interplanetary sources of geomagnetic storm on 7-10 November, 2004 have also bee

E. Emsiz, E. M. Opdam, J. V. Stokman

For any module over the affine Weyl group we construct a representation of the associated trigonometric Cherednik algebra $A(k)$ at critical level in terms of Dunkl type operators. Under this representation the center of $A(k)$ produces quantum conserved integrals for root system generalizations of quantum spin-particle systems on the circle with delta funct

Dastgeer Shaikh, G. P. Zank

We have developed a time-dependent three-dimensional model of isotropic, adiabatic, and compressible magnetohydrodynamic plasma to understand nonlinear cascades of density fluctuations in local interstellar medium. Our simulations, describing evolution of initial supersonic, super Alfvénic plasma modes, indicate that nonlinear interactions lead to damping of

Sundance Bilson-Thompson, Jonathan Hackett, Lou Kauffman, Lee Smolin

We develop the idea that the particles of the standard model may arise from excitations of quantum geometry. A previously proposed topological model of preons is developed so that it incorporates an unbounded number of generations. A condition is also found on quantum gravity dynamics necessary for the interactions of the standard model to emerge.

David P. Blecher, Benton L. Duncan

In analogy with the C*-algebra theory, we study variants appropriate to nonselfadjoint algebras of nuclearity, the local lifting property, exactness, and the weak expectation property. In addition, we study the relationships between these notions, and how they are connected with the classical C*-algebra theory through the use of C*-algebras generated by the

I. de Medeiros Varzielas

We consider an existing framework of models where the neutrino Dirac and Majorana mass terms are related, and clarify how the mass structures interact through the type I seesaw mechanism, producing exact tri-bi-maximal mixing for the effective neutrinos in the limit of strong Majorana mass hierarchy (sequential dominance). In order to better illustrate this,

S. M. Giampaolo, G. Adesso, F. Illuminati

We introduce a general analytic approach to the study of factorization points and factorized ground states in quantum cooperative systems. The method allows to determine rigorously existence, location, and exact form of separable ground states in a large variety of, generally non-exactly solvable, spin models belonging to different universality classes. The

Sergio L. Cacciatori, Dietmar Klemm, Diego S. Mansi, Emanuele Zorzan

The timelike supersymmetric solutions of N=2, D=4 gauged supergravity coupled to an arbitrary number of abelian vector multiplets are classified using spinorial geometry techniques. We show that the generalized holonomy group for vacua preserving N supersymmetries is GL((8-N)/2,C) $\ltimes$ N/2 C^((8-N)/2) $\subseteq$ GL(8,R), where N=0,2,4,6,8. The spacetim