September 2008 arXiv papers — page 9

Markus Brede

In this letter we discuss a method for generating synchrony-optimized coupling architectures of Kuramoto oscillators with a heterogeneous distribution of native frequencies. The method allows us to relate the properties of the coupling network to its synchronizability. These relations were previously only established from a linear stability analysis of the i

Wing-Kin Ma, Chao-Cheng Su, Joakim Jalden, Tsung-Hui Chang

In multi-input-multi-output (MIMO) detection, semidefinite relaxation (SDR) has been shown to be an efficient high-performance approach. Developed initially for BPSK and QPSK, SDR has been found to be capable of providing near-optimal performance (for those constellations). This has stimulated a number of recent research endeavors that aim to apply SDR to th

Garret Sobczyk, Omar Leon Sanchez

A simple but rigorous proof of the Fundamental Theorem of Calculus is given in geometric calculus, after the basis for this theory in geometric algebra has been explained. Various classical examples of this theorem, such as the Green's and Stokes' theorem are discussed, as well as the new theory of monogenic functions, which generalizes the concept o

William J. Heinzer, Louis J. Ratliff, David E. Rush

Let V be a rank one discrete valuation ring (DVR) on a field F and let L/F be a finite separable algebraic field extension with [L:F] = m. The integral closure of V in L is a Dedekind domain that encodes the following invariants: (i) the number of extensions of V to a valuation ring W on L, (ii) the residue degree of each W over V, and (iii) the ramification

Ann Merchant Boesgaard, Julie A. Krugler

We have determined Be abundances in 50 F and G dwarfs in the mass range of 0.9 $\leq$ M$_\odot$ $\leq$ 1.1 as determined by Lambert & Reddy. The effective temperatures are 5600 to 6400 K and metallicities from $-$0.65 to +0.11. The spectra were taken primarily with Keck I + HIRES. The Be abundances were found via spectral synthesis of Be II lines near 3130 Å

Itzhak Goldman

A recent paper by Stanimirovic etal (2008) presents quit interesting results from HI observations of the Magellanic Stream (MS) tip. The high spatial resolution of the data reveals rich and complex morphological and kinematic structures; notably four coherent HI substreams extending over angular size of about 20 deg were found. We use the position-velocity i

Thomas F. Miller

Ring polymer molecular dynamics (RPMD) is used to directly simulate the dynamics of an excess electron in a supercritical fluid over a broad range of densities. The accuracy of the RPMD model is tested against numerically exact path integral statistics through the use of analytical continuation techniques. At low fluid densities, the RPMD model substantially

Yuri Berest

In these notes, we give a survey of the main results of [BC] and [BW]. Our aim is to generalize the geometric classification of (one-sided) ideals of the first Weyl algebra $ A_1(C) $ (see [BW1, BW2]) to the ring $ D(X) $ of differential operators on an arbitrary complex smooth affine curve X. We approach this problem in two steps: first, we classify the ide

Ahmet A. Husainov

For any free partially commutative monoid $M(E,I)$, we compute the global dimension of the category of $M(E,I)$-objects in an Abelian category with exact coproducts. As a corollary, we generalize Hilbert's Syzygy Theorem to polynomial rings in partially commuting variables.

B. -Q. For, H. Edelmann, E. M. Green, H. Drechsel

We report preliminary VRI differential photometric and spectroscopic results for KBS 13, a recently discovered non-eclipsing sdB+dM system. Radial velocity measurements indicate an orbital period of 0.2923 +/- 0.0004 days with a semi-amplitude velocity of 22.82 +/- 0.23 km s-1. This suggests the smallest secondary minimum mass yet found. We discuss the distr

Rosemary F. G. Wyse

I discuss how the chemical abundance distributions, kinematics and age distributions of stars in the thin and thick disks of the Galaxy can be used to decipher the merger history of the Milky Way, a typical large galaxy. The observational evidence points to a rather quiescent past merging history, unusual in the context of the `consensus' cold-dark-matte

Christof Gattringer, C. B. Lang, Markus Limmer, Thilo Maurer

We present recent results of our dynamical simulations with Chirally Improved fermions and report on new developments in the determination of excited light-quark meson states using interpolators constructed by applying covariant derivatives on Jacobi-smeared quark sources within the framework of the variational method.

Neil Barnaby, Niky Kamran

Infinite order differential equations have come to play an increasingly significant role in theoretical physics. Field theories with infinitely many derivatives are ubiquitous in string field theory and have attracted interest recently also from cosmologists. Crucial to any application is a firm understanding of the mathematical structure of infinite order p

D. Dalmazi, F. L. Sá

In ferromagnetic spin models above the critical temperature ($T > T_{cr}$) the partition function zeros accumulate at complex values of the magnetic field ($H_E$) with a universal behavior for the density of zeros $ρ(H) \sim | H - H_E |^{\sg}$. The critical exponent $\sg$ is believed to be universal at each space dimension and it is related to the magnetic s

Pallab Basu, Anindya Mukherjee, Hsien-Hang Shieh

In arXiv:0803.3295 [hep-th] a holographic black hole solution is discussed which exhibits a superconductor like transition. In the superconducting phase the black holes show infinite DC conductivity. This gives rise to the possibility of deforming the solutions by turning on a time independent current (supercurrent), without any electric field. This type of

Itzhak Fouxon, Yaron Oz

We consider the hydrodynamics of relativistic conformal field theories at finite temperature. We show that the limit of slow motions of the ideal hydrodynamics leads to the non-relativistic incompressible Euler equation. For viscous hydrodynamics we show that the limit of slow motions leads to the non-relativistic incompressible Navier-Stokes equation. We ex

Emil Prodan

Quantum Spin-Hall systems are topological insulators displaying dissipationless spin currents flowing at the edges of the samples. In contradistinction to the Quantum Hall systems where the charge conductance of the edge modes is quantized, the spin conductance is not and it remained an open problem to find the observable whose edge current is quantized. In

Pierre-Philippe Dechant, Anthony N. Lasenby, Michael P. Hobson

We present a novel cosmological model in which scalar field matter in a biaxial Bianchi IX geometry leads to a non-singular `pancaking' solution: the hypersurface volume goes to zero instantaneously at the `Big Bang', but all physical quantities, such as curvature invariants and the matter energy density remain finite, and continue smoothly through t

Elemer E Rosinger

Part 1 : For more than two millennia, ever since Euclid's geometry, the so called Archimedean Axiom has been accepted without sufficiently explicit awareness of that fact. The effect has been a severe restriction of our views of space-time, a restriction which above all affects Physics. Here it is argued that, ever since the invention of Calculus by Newt

Santiago Capriotti

The usual treatment of a (first order) classical field theory such as electromagnetism has a little drawback: It has a primary constraint submanifold that arise from the fact that the dynamics is governed by the antisymmetric part of the jet variables. So it is natural to ask if there exists a formulation of this kind of field theories which avoids this prob

Avery E. Broderick, Vincent L. Fish, Sheperd S. Doeleman, Abraham Loeb

Recent millimeter-VLBI observations of Sagittarius A* (Sgr A*) have, for the first time, directly probed distances comparable to the horizon scale of a black hole. This provides unprecedented access to the environment immediately around the horizon of an accreting black hole. We leverage both existing spectral and polarization measurements and our present un

Aleš Černý

We provide a full characterization of the oblique projector $U(VU)^+V$ in the general case where the range of $U$ and the null space of $V$ are not complementary subspaces. We discuss the new result in the context of constrained least squares minimization.

Paul Benioff

This work is based on the field of reference frames based on quantum representations of real and complex numbers described in other work. Here frame domains are expanded to include space and time lattices. Strings of qukits are described as hybrid systems as they are both mathematical and physical systems. As mathematical systems they represent numbers. As p

Geraldo Botelho, Daniel Pellegrino, Pilar Rueda

The aim of this paper is to prove a stronger version of a conjecture on the existence of non-dominated scalar-valued m-homogeneous polynomials (m>=3) on arbitrary infinite dimensional Banach spaces.

Vincent L. Fish, Avery E. Broderick, Sheperd S. Doeleman, Abraham Loeb

The recent detection of Sagittarius A* at lambda = 1.3 mm on a baseline from Hawaii to Arizona demonstrates that millimeter wavelength very long baseline interferometry (VLBI) can now spatially resolve emission from the innermost accretion flow of the Galactic center region. Here, we investigate the ability of future millimeter VLBI arrays to constrain the s

Yan-Chuan Cai, Shaun Cole, Adrian Jenkins, Carlos Frenk

In a universe with a cosmological constant, the large-scale gravitational potential varies in time and this is, in principle, observable. Using an N-body simulation of a $Λ$CDM universe, we show that linear theory is not sufficiently accurate to predict the power spectrum of the time derivative, $\dotΦ$, needed to compute the imprint of large-scale structure

Igor A. Batalin, Klaus Bering

We introduce an antisymplectic Dirac operator and antisymplectic gamma matrices. We explore similarities between, on one hand, the Schroedinger-Lichnerowicz formula for spinor bundles in Riemannian spin geometry, which contains a zeroth-order term proportional to the Levi-Civita scalar curvature, and, on the other hand, the nilpotent, Grassmann-odd, second-o

Piotr Faliszewski, Edith Hemaspaandra, Lane A. Hemaspaandra, Joerg Rothe

The only systems previously known to be resistant to all the standard control types were highly artificial election systems created by hybridization. We study a parameterized version of Copeland voting, denoted by Copeland^α, where the parameter αis a rational number between 0 and 1 that specifies how ties are valued in the pairwise comparisons of candidates

X. S. Xu, M. Angst, T. V. Brinzari, R. P. Hermann

We investigated the series of temperature and field-driven transitions in LuFe$_2$O$_4$ by optical and Mössbauer spectroscopies, magnetization, and x-ray scattering in order to understand the interplay between charge, structure, and magnetism in this multiferroic material. We demonstrate that charge fluctuation has an onset well below the charge ordering tra

H. Lee Price

In 1967 the Dutch mathemetician F.J.M. Barning described an infinite, planar, ternary tree*. Seven years later, A. Hall independently discovered the same tree. Both used the method of uni-modular matrices to transform one triple to another. A number of rediscoveries have occurred more recently. In this article we announce the discovery of an entirely differe

David Harbater, Julia Hartmann, Daniel Krashen

This paper provides applications of patching to quadratic forms and central simple algebras over function fields of curves over henselian valued fields. In particular, we use a patching approach to reprove and generalize a recent result of Parimala and Suresh on the u-invariant of p-adic function fields, for p odd. The strategy relies on a local-global princ

Andrew Putman

Let $Γ$ be a finite-index subgroup of the mapping class group of a closed genus $g$ surface that contains the Torelli group. For instance, $Γ$ can be the level $L$ subgroup or the spin mapping class group. We show that $H_2(Γ;\Q) \cong \Q$ for $g \geq 5$. A corollary of this is that the rational Picard groups of the associated finite covers of the moduli spa

D0 Collaboration, V. Abazov

We search for charged massive long-lived particles using 1.1 fb$^{-1}$ of data collected by the D0 detector at the Fermilab Tevatron $p\bar{p}$ Collider. Time-of-flight information is used to search for pair produced long-lived tau sleptons, gaugino-like charginos, and higgsino-like charginos. We find no evidence of a signal and set 95% C.L. cross section up

Gerard H. E. Duchamp, Florent Hivert, Jean-Christophe Novelli, Jean-Yves Thibon

We prove a Cauchy identity for free quasi-symmetric functions and apply it to the study of various bases. A free Weyl formula and a generalization of the splitting formula are also discussed.

Ulf Gran, Bengt E. W. Nilsson

This paper is concerned with the problem of coupling the N=8 superconformal Bagger-Lambert-Gustavsson (BLG) theory to N=8 conformal supergravity in three dimensions. We start by constructing the on-shell N=8 conformal supergravity in three dimensions consisting of a Chern-Simons type term for each of the gauge fields: the spin connection, the SO(8) R-symmetr

Egor Babaev

I consider electrodynamics and the problem of knotted solitons in two-component superconductors. Possible existence of knotted solitons in multicomponent superconductors was predicted several years ago. However their basic properties and stability in these systems remains an outstandingly difficult question both for analytical and numerical treatment. Here I

S. E. Shafranjuk

A directional photon-assisted resonant chiral tunneling through a bilayer graphene barrier is considered. An external electromagnetic field applied to the barrier switches the transparency $T$ in the longitudinal direction from its steady state value T=0 to the ideal T=1 at no energy costs. The switch happens because the a.c. field affects the phase correlat

Charlie Conroy, James E. Gunn, Martin White

The stellar masses, mean ages, metallicities, and star formation histories of galaxies are now commonly estimated via stellar population synthesis (SPS) techniques. SPS relies on stellar evolution calculations from the main sequence to stellar death, stellar spectral libraries, phenomenological dust models, and stellar initial mass functions (IMFs). The pres

Nathan Seiberg, Tomer Volansky, Brian Wecht

We describe a framework for gauge mediation of supersymmetry breaking in which the messengers are charged under the hidden sector gauge group but do not play a role in breaking supersymmetry. From this point of view, our framework is between ordinary gauge mediation and direct mediation. As an example, we consider the 3-2 model of dynamical supersymmetry bre

Soo-hyeon Nam

We discuss the aspects of the little Higgs model with the $SU(4)_L \times U(1)_X$ electroweak gauge group as an alternative solution to the naturalness and fine-tuning issues. We introduce anomaly-free fermion spectra, and present their interactions with the physical gauge bosons. We also discuss some phenomenological implications of these fermions and the e

Devang A. Joshi, A. Thamizhavel, S. K. Dhar

The results of the magnetization studies on Pr_{5}Ge_{3}and Tb_{5}Ge_{3} single crystals are reported. Single Crystals of Pr_{5}Ge_{3} and Tb_{5}Ge_{3} compounds were successfully grown by Czochralski method. These compounds crystallize in a Mn_{5}Si_{3} type hexagonal structure with space group P6_{3}/mcm. Ferromagnetic correlations set in at around 36 K in

R. Lipperheide, U. Wille

Spin-polarized electron transport in diluted magnetic semiconductors (DMS) in the paramagnetic phase is described within the thermoballistic transport model. In this (semiclassical) model, the ballistic and diffusive transport mechanisms are unified in terms of a thermoballistic current in which electrons move ballistically across intervals enclosed between

Yidun Wan

We study interactions amongst topologically conserved excitations of quantum theories of gravity, in particular the braid excitations of four-valent spin networks. These have been shown previously to propagate and interact under evolution rules of spin foam models. We show that the dynamics of these braid excitations can be described by an effective theory b

Peter Vermeire

Under certain effective positivity conditions, we show that the secant variety to a smooth variety satisfies $N_{3,p}$. For smooth curves, we provide the best possible effective bound on the degree $d$ of the embedding, $d\geq 2g+3+p$.

Itzel Lucio Martinez, Philip Chan, Xiaofan Mo, Steve Hosier

We propose and investigate a fibre-based quantum key distribution system, which employs polarization qubits encoded into faint laser pulses. As a novel feature, it allows sending of classical framing information via sequences of strong laser pulses that precede the quantum data. This allows synchronization, sender and receiver identification, and compensatio

Supriyo Datta

Nanoscale electronic devices are of great interest for all kinds of applications like switching, energy conversion and sensing. The objective of this chapter, however, is not to discuss specific devices or applications. Rather it is to convey the conceptual framework that has emerged over the last twenty years, which is important not only because of the prac

L. Tian

We present a ground state cooling scheme for a nanomechanical resonator linearly coupled with a LC oscillator. The linear coupling, when periodically modulated at red detuning, up-converts the low-frequency nanomechanical mode to the high-frequency LC oscillator mode and generates backaction force that can cool the resonator to its ground state in the resolv

D. V. Evtushinsky, D. S. Inosov, V. B. Zabolotnyy, A. Koitzsch

The precise momentum dependence of the superconducting gap in the iron-arsenide superconductor with Tc = 32K (BKFA) was determined from angle-resolved photoemission spectroscopy (ARPES) via fitting the distribution of the quasiparticle density to a model. The model incorporates finite lifetime and experimental resolution effects, as well as accounts for pecu

Edward Frenkel, David Hernandez

We establish a correspondence (or duality) between the characters and the crystal bases of finite-dimensional representations of quantum groups associated to Langlands dual semi-simple Lie algebras. This duality may also be stated purely in terms of semi-simple Lie algebras. To explain this duality, we introduce an "interpolating quantum group" depen

Qi Guo, Simon D. M. White

We study model predictions for three high-redshift galaxy populations: Lyman break galaxies at z~3 (LBGs), optically selected star-forming galaxies at z~2 (BXs), and distant red galaxies at z~2 (DRGs).Our galaxy formation model simultaneously reproduces the abundances, redshift distributions and clustering of all three observed populations. The star formatio

Kingshook Biswas, Mahan Mj

For $i= 1,2$, let $G_i$ be cocompact groups of isometries of hyperbolic space $\Hyp^n$ of real dimension $n$, $n \geq 3$. Let $H_i \subset G_i$ be infinite index quasiconvex subgroups satisfying one of the following conditions: 1) limit set of $H_i$ is a codimension one topological sphere. 2) limit set of $H_i$ is an even dimensional topological sphere. 3) $

Aurel Rascanu, Eduard Rotenstein

Using the Fitzpatrick function, we characterize the solutions for different classes of deterministic and stochastic differential equations driven by maximal monotone operators (or in particular subdifferential operators) as the minimum point of a suitably chosen convex lower semicontinuous function. Such technique provides a new approach for the existence of

B. Z. Kopeliovich, A. H. Rezaeian, Ivan Schmidt

We investigate the azimuthal asymmetry v2 of produced pions in pp and pA collisions at both RHIC and SPS energies. In our approach, based on the pQCD parton model and the light-cone QCD-dipole formalism, the azimuthal asymmetry results from a correlation between the color-dipole orientation and the impact parameter of the collision. We introduce the color-di

Raphael Campos Drumond, Marcelo de Oliveira Terra Cunha

A given dynamics for a composite quantum system can exhibit several distinct properties for the asymptotic entanglement behavior, like entanglement sudden death, asymptotic death of entanglement, sudden birth of entanglement, etc. A classification of the possible situations was given in [M. O. Terra Cunha, {\emph{New J. Phys}} {\bf{9}}, 237 (2007)] but for s

Sourish Dutta, Robert J. Scherrer

We examine hilltop quintessence models, in which the scalar field is rolling near a local maximum in the potential, and w is close to -1. We first derive a general equation for the evolution of the scalar field in the limit where w is close to -1. We solve this equation for the case of hilltop quintessence to derive w as a function of the scale factor; these

Paolo Ciarcelluti, Robert Foot

Mirror dark matter provides a simple framework for which to explain the DAMA/Libra annual modulation signal consistently with the null results of the other direct detection experiments. The simplest possibility involves ordinary matter interacting with mirror dark matter via photon-mirror photon kinetic mixing of strength epsilon ~ 10^(-9). We confirm that p

Andrea Fiege, Timo Aspelmeier, Annette Zippelius

We study the velocity autocorrelation function (VACF) of a driven granular fluid in the stationary state in 3 dimensions. As the critical volume fraction of the glass transition in the corresponding elastic system is approached, we observe pronounced cage effects in the VACF as well as a strong decrease of the diffusion constant. At moderate densities the VA

Stefan Groot Nibbelink, Filipe Paccetti Correia, Michele Trapletti

Instantons on Eguchi-Hanson spaces provide explicit examples of stable bundles on non-compact four dimensional C^2/Z_n orbifold resolutions with non-Abelian structure groups. With this at hand, we can consider compactifications of ten dimensional SO(32) supergravity (arising as the low energy limit of the heterotic string) on the resolved spaces in the prese

Bess Yiyuan Fang, Patrizia Vignolo, Christian Miniatura, Anna Minguzzi

We consider a strongly interacting one-dimensional (1D) Bose-Fermi mixture confined in a harmonic trap. It consists of a Tonks-Girardeau (TG) gas (1D Bose gas with repulsive hard-core interactions) and of a non-interacting Fermi gas (1D spin-aligned Fermi gas), both species interacting through hard-core repulsive interactions. Using a generalized Bose-Fermi

K. Abe, J. Hosaka, T. Iida, M. Ikeda

A high performance distillation system to remove krypton from xenon was constructed, and a purity level of Kr/Xe = $\sim 3 \times 10^{-12}$ was achieved. This development is crucial in facilitating high sensitivity low background experiments such as the search for dark matter in the universe.

Nick Gill, Anupam Singh

We classify the real and strongly real conjugacy classes in $GL_n(q)$, $SL_n(q)$, $PGL_n(q)$, $PSL_n(q)$, and all quasi-simple covers of $PSL_n(q)$. In each case we give a formula for the number of real, and the number of strongly real, conjugacy classes.

Anne-Christine Davis, Senthooran Rajamanoharan

We present a new method for finding lower bounds on the energy of topological cosmic string solutions in gravitational field theories. This new method produces bounds that are valid over the entire space of solutions, unlike the traditional approach, where the bounds obtained are only valid for cylindrically symmetric solutions. This method is shown to be a

Mariana Haim, Blas Torrecillas

We study the problem of whether a coalgebra that generates its category of left (right) comodules is left (right) quasi-coFrobenius or not. We prove it does not hold in general, by giving a method of constructing counterexamples. This gives a negative answer to a question stated in \cite{kn:coalgen}. We also prove it is true for monomial pointed coalgebras a

Oki Miura, Takeo Fujiwara

LDA+DMFT method in the framework of the iterative perturbation theory (IPT) with full LDA Hamiltonian without mapping onto the effective Wannier orbitals. We then apply this LDA+DMFT method to ferromagnetic bcc-Fe and fcc-Ni as a test of transition metal, and to antiferromagnetic NiO as an example of transition metal oxide. In Fe and Ni, the width of occupie

Jennifer James, Thomas Koberda, Kathryn Lindsey, Cesar E. Silva

We examine some of the properties of uniformly rigid transformations, and analyze the compatibility of uniform rigidity and (measurable) weak mixing along with some of their asymptotic convergence properties. We show that on Cantor space, there does not exist a finite measure-preserving, totally ergodic, uniformly rigid transformation. We briefly discuss gen

Jeffrey Schenker

It is shown that certain ensembles of random matrices with entries that vanish outside a band around the diagonal satisfy a localization condition on the resolvent which guarantees that eigenvectors have strong overlap with a vanishing fraction of standard basis vectors, provided the band width $W$ raised to a power $μ$ remains smaller than the matrix size $

N. Qureshi, M. Zbiri, J. Rodríguez-Carvajal, A. Stunault

We present a combination of ab initio calculations, magnetic Compton scattering and polarized neutron experiments, which elucidate the density distribution of unpaired electrons in the kagome staircase system Co3V2O8. Ab initio wave functions were used to calculate the spin densities in real and momentum space, which show good agreement with the respective e

Jared C. Bronski, Mathew A. Johnson

We study the spectral stability of a family of periodic standing wave solutions to the generalized KdV (g-KdV) in a neighborhood of the origin in the spectral plane using what amounts to a rigorous Whitham modulation theory calculation. In particular we are interested in understanding the role played by the null directions of the linearized operator in the s

Michal Sedlak, Mario Ziman

We address the problem of unambiguous comparison of a pair of unknown qudit unitary channels. Using the framework of process positive operator valued measures (PPOVM) we characterize all solutions and identify the optimal ones. We prove that the entanglement is the key ingredient in designing the optimal experiment for comparison of unitary channels. Without

Hau-wen Huang, Chih-wen Weng

Let $X=(V,E)$ be a finite simple connected graph with $n$ vertices and $m$ edges. A configuration is an assignment of one of two colors, black or white, to each edge of $X.$ A move applied to a configuration is to select a black edge $ε\in E$ and change the colors of all adjacent edges of $ε.$ Given an initial configuration and a final configuration, try to

Sayantani Bhattacharyya, R. Loganayagam, Ipsita Mandal, Shiraz Minwalla

We generalize recent work to construct a map from the conformal Navier Stokes equations with holographically determined transport coefficients, in d spacetime dimensions, to the set of asymptotically locally AdS_{d+1} long wavelength solutions of Einstein's equations with a negative cosmological constant, for all d>2. We find simple explicit expressions

Franziska Synatschke, Georg Bergner, Holger Gies, Andreas Wipf

We study supersymmetric quantum mechanics with the functional RG formulated in terms of an exact and manifestly off-shell supersymmetric flow equation for the effective action. We solve the flow equation nonperturbatively in a systematic super-covariant derivative expansion and concentrate on systems with unbroken supersymmetry. Already at next-to-leading or

Preeti Parashar, Swapan Rana

We prove that the most general W class of N-qubit states are uniquely determined among arbitrary states (pure or mixed) by just their bipartite reduced density matrices. Moreover, if we consider only pure states, then (N-1) of them are shown to be sufficient.

Pedro Silva, Pascal Weil

We show that the following problems are decidable in a rank 2 free group F_2: does a given finitely generated subgroup H contain primitive elements? and does H meet the orbit of a given word u under the action of G, the group of automorphisms of F_2? Moreover, decidability subsists if we allow H to be a rational subset of F_2, or alternatively if we restrict

Qing-Hu Chen, Yu-Yu Zhang, Tao Liu, Ke-Lin Wang

By using extended bosonic coherent states, a new technique to solve the Dicke model exactly is proposed in the numerical sense. The accessible system size is two orders of magnitude higher than that reported in literature. Finite-size scaling for several observables, such as the ground-state energy, Berry phase, and concurrence are analyzed. The existing dis

Bhuvanesh Sundar, Alasdair C. Hamilton, Johannes Courtial

We describe local light-ray rotation in terms of complex refractive indices. We show that Fermat's principle holds, and we derive an extended Snell's law. The change in the angle of a light ray with respect to the normal to a refractive-index interface is described by the modulus of the refractive-index ratio, the rotation around the interface normal

Jordan P. Skittrall

In extra dimensional models with Kaluza-Klein graviton states that are well separated in mass, such states may be observed as resonances in collider experiments. We extend previous works on such scenarios by considering the one-loop resonant production of a Z boson in association with a photon. We find the production rate to be negligible in conservative sce

Alasdair C. Hamilton, Johannes Courtial

A ray-rotation sheet consists of miniaturized optical components that function - ray optically - as a homogeneous medium that rotates the local direction of transmitted light rays around the sheet normal by an arbitrary angle [A. C. Hamilton et al., arXiv:0809.2646 (2008)]. Here we show that two or more parallel ray-rotation sheets perform imaging between tw

Andreas O. Bender

A monic polynomial in F_q[t] of degree n over a finite field F_q of odd characteristic can be written as the sum of two irreducible monic elements in F_q[t] of degrees n and n-1 if q is larger than a bound depending only on n. The main tool is a sufficient condition for simultaneous primality of two polynomials in one variable x with coefficients in F_q[t].

Alasdair C. Hamilton, Johannes Courtial

Volumes of sub-wavelength electromagnetic elements can act like homogeneous materials: metamaterials. In analogy, sheets of optical elements such as prisms can act ray-optically like homogeneous sheet materials. In this sense, such sheets can be considered to be metamaterials for light rays (METATOYs). METATOYs realize new and unusual transformations of the

Gustavo Dotti, Julio Oliva, Ricardo Troncoso

The classification of certain class of static solutions for the Einstein-Gauss-Bonnet theory in vacuum is presented. The spacelike section of the class of metrics under consideration is a warped product of the real line with a nontrivial base manifold. For arbitrary values of the Gauss-Bonnet coupling, the base manifold must be Einstein with an additional sc

Giuseppe Bimonte, Luca Cappellin, Giovanni Carugno, Giuseppe Ruoso

We report new measurements of the linear polarization of thermal radiation emitted by incandescent thin tungsten wires, with thicknesses ranging from five to hundred microns. Our data show very good agreement with theoretical predictions, based on Drude-type fits to measured optical properties of tungsten.

T. P. Billam, S. A. Gardiner

Under certain conditions, the quantum delta-kicked harmonic oscillator displays quantum resonances. We consider an atom-optical realization of the delta-kicked harmonic oscillator, and present a theoretical discussion of the quantum resonances that could be observed in such a system. Having outlined our model of the physical system we derive the values at wh

M. Fujikawa, Y. Yusa

We report measurements of CP violation parameters in $B^0 \to K^0 π^0$ decays based on a data sample of $657 \times 10^6 B\bar{B}$ pairs collected with the Belle detector at the KEKB $e^+ e^-$ asymmetric-energy collider. We use $B^0 \to K^0_S π^0$ decays for both mixing-induced and direct $CP$ violating asymmetry measurements and $B^0 \to K^0_L π^0$ decays f

Smitha Subramanian, Annapurni Subramaniam

We used the red clump stars from the photometric data of the Optical Gravitational Lensing Experiment(OGLE II) survey and the Magellanic Cloud Photometric Survey (MCPS) for both the Clouds to estimate the depth.The observed dispersion in the magnitude and colour distribution of red clump stars is used to estimate the depth, after correcting for population ef

Gabriel P. Paternain

Let $(M,g)$ be a closed oriented negatively curved surface. A unitary connection on a Hermitian vector bundle over $M$ is said to be transparent if its parallel transport along the closed geodesics of $g$ is the identity. We study the space of such connections modulo gauge and we prove a classification result in terms of the solutions of certain PDE that ari

Adan Cabello, Alessandro Rossi, Giuseppe Vallone, Francesco De Martini

Franson's Bell experiment with energy-time entanglement [Phys. Rev. Lett. 62, 2205 (1989)] does not rule out all local hidden variable models. This defect can be exploited to compromise the security of Bell inequality-based quantum cryptography. We introduce a novel Bell experiment using genuine energy-time entanglement, based on a novel interferometer,

Tobias Hurth

We present theoretical and experimental preparations for an indirect search for new physics using the rare decay $\bar B_d \to \bar K^* l^+ l^-$. We design new observables with very small theoretical uncertainties and good experimental resolution.

Sebastien Clesse, Jonathan Rocher

Hybrid inflation faces two well-known problems: the blue spectrum of the non-supersymmetric version of the model and the fine-tuning of the initial conditions of the fields leading to sufficient inflation to account for the standard cosmological problems. They are investigated by studying the exact two-fields dynamics instead of assuming slow-roll. When the

Mehdi Kargarian

The entanglement properties of a class of topological stabilizer states, the so called \emph{topological color codes} defined on a two-dimensional lattice or \emph{2-colex}, are calculated. The topological entropy is used to measure the entanglement of different bipartitions of the 2-colex. The dependency of the ground state degeneracy on the genus of the su

Dariusz Buraczewski, Ewa Damek, Yves Guivarc'h

We consider a Markov chain $\{X_n\}_{n=0}^\8$ on $\R^d$ defined by the stochastic recursion $X_{n}=M_n X_{n-1}+Q_n$, where $(Q_n,M_n)$ are i.i.d. random variables taking values in the affine group $H=\R^d\rtimes {\rm GL}(\R^d)$. Assume that $M_n$ takes values in the similarity group of $\R^d$, and the Markov chain has a unique stationary measure $ν$, which h

Adam Skalski

Let E be a product system of C*-correspondences over N^r. Some sufficient conditions for the existence of a not necessarily regular isometric dilation of a completely contractive representation of E are established and difference between regular and *-regular dilations discussed. It is in particular shown that a minimal isometric dilation is *-regular if and

Mun Dae Kim

We study the quantum operation of coupled superconducting flux qubits under a microwave irradiation. The flux qubits can be described as magnetic dipole moments in the limit of weak microwave field amplitude consistent with usual experimental situations. With the Hamiltonian for coupled qubits under a microwave field, we show that a strong coupling enables t

S. Takayoshi, W. Kokuyama, Hiroshi Fukuyama

When He gas is injected from room temperature into boiling liquid N$_{2}$, boiling is suppressed, leaving liquid surface flat like a mirror. Although the qualitative explanation for this phenomenon is known [Minkoff G J \textit{et al}. Nature 1957;180(4599):1413-4.], it has not been studied quantitatively and comprehensively yet. In this report, we made care

Michele Rossi, Lea Terracini

In the present paper MAPLE subroutines computing Milnor and Tyurina numbers of an isolated algebraic hypersurface singularity are presented and described in detail. They represents examples, and perhaps the first ones, of a MAPLE implementation of local monomial ordering. As an application, the last section is devoted to writing down equations of algebraic s

Patrick Popescu-Pampu

Each elliptic curve can be embedded uniquely in the projective plane, up to projective equivalence. The hessian curve of the embedding is generically a new elliptic curve, whose isomorphism type depends only on that of the initial elliptic curve. One gets like this a rational map from the moduli space of elliptic curves to itself. We call it the hessian dyna

O. Kamps, R. Friedrich, R. Grauer

We present a formal connection between Lagrangian and Eulerian velocity increment distributions which is applicable to a wide range of turbulent systems ranging from turbulence in incompressible fluids to magnetohydrodynamic turbulence. For the case of the inverse cascade regime of two-dimensional turbulence we numerically estimate the transition probabiliti

Ramkrishna Das, Dipankar Banerjee, Nagarhalli Ashok, Olivier Chesneau

We present spectroscopic and photometric results of Nova V1280 Sco which was discovered in outburst in early 2007 February. The large number of spectra obtained of the object leads to one of the most extensive, near-infrared spectral studies of a classical nova. The spectra evolve from a P-Cygni phase to an emission-line phase and at a later stage is dominat

Elisa Gorla

We study the family of ideals generated by minors of mixed size contained in a ladder of a symmetric matrix from the point of view of liaison theory. We prove that they can be obtained from ideals of linear forms by ascending G-biliaison. In particular, they are glicci.

Hans Heymans, Isar Stubbe

We explain the precise relationship between two module-theoretic descriptions of sheaves on an involutive quantale, namely the description via so-called Hilbert structures on modules and that via so-called principally generated modules. For a principally generated module satisfying a suitable symmetry condition we observe the existence of a canonical Hilbert