April 2008 arXiv papers — page 46

Ki-Seok Kim

We propose one possible mechanism for deconfinement based on an SU(2) slave-boson theory. Resorting to an effective field theory approach, we show that introduction of an isospin interaction potential gives rise to a fermion zero mode in an instanton-hedgehog configuration. As a result, meron-type vortices are allowed. We demonstrate how emergence of such vo

Michael Barnard, Augusta Abrahamse, Andreas Albrecht, Brandon Bozek

We evaluate the ability of future data sets to discriminate among different quintessence dark energy models. This approach gives an alternative measure for assessing the impact of future experiments, as compared with the large body of literature that compares experiments in abstract parameter spaces and more recent work that evaluates the constraining power

The BABAR Collaboration, B. Aubert

Using 383 million BBbar pairs from the BaBar data sample, we report results for branching fractions of six charged B-meson decay modes, where a charged kaon recoils against a charmless resonance decaying to KKbar* or etapipi final states with mass in the range (1.2-1.8)gev/c^2. We observe a significant enhancement at the low KK*bar invariant mass which is in

Ayoub Otmani, Jean-Pierre Tillich, Leonard Dallot

We cryptanalyse here two variants of the McEliece cryptosystem based on quasi-cyclic codes. Both aim at reducing the key size by restricting the public and secret generator matrices to be in quasi-cyclic form. The first variant considers subcodes of a primitive BCH code. We prove that this variant is not secure by finding and solving a linear system satisfie

Vasilis Chousionis, Pertti Mattila

We shall consider the truncated singular integral operators T_{μ, K}^εf(x)=\int_{\mathbb{R}^{n}\setminus B(x,ε)}K(x-y)f(y)dμy and related maximal operators $T_{μ,K}^{\ast}f(x)=\underset{ε>0}{\sup}| T_{μ,K}^εf(x)|$. We shall prove for a large class of kernels $K$ and measures $μ$ and $ν$ that if $μ$ and $ν$ are separated by a Lipschitz graph, then $T_{ν,K}^{\

Enrico Le Donne

This paper is connected with the problem of describing path metric spaces that are homeomorphic to manifolds and biLipschitz homogeneous, i.e., whose biLipschitz homeomorphism group acts transitively. Our main result is the following. Let $X = G/H$ be a homogeneous manifold of a Lie group $G$ and let $d$ be a geodesic distance on $X$ inducing the same topolo

Birgit Richter

We construct a combinatorially defined involution on the algebraic $K$-theory of the ring spectrum associated to a bimonoidal category with anti-involution. Particular examples of such are braided bimonoidal categories. We investigate examples such as algebraic K-theory of connective complex and real topological K-theory and Waldhausen's K-theory of spac

Azita Mayeli

We present a notion of frame multiresolution analysis on the Heisenberg group, abbreviated by FMRA, and study its properties. Using the irreducible representations of this group, we shall define a sinc-type function which is our starting point for obtaining the scaling function. Further, we shall give a concrete example of a wavelet FMRA on the Heisenberg gr

Anna Fino, Adriano Tomassini

On a compact complex manifold we study the behaviour of strong Kähler with torsion (strong KT) structures under small deformations of the complex structure and the problem of extension of a strong KT metric. In this context we obtain the analogous result of Miyaoka extension theorem. Studying the blow-up of a strong KT manifold at a point or along a complex

Adam Kasperski, Pawel Zielinski

In this paper the minmax (regret) versions of some basic polynomially solvable deterministic network problems are discussed. It is shown that if the number of scenarios is unbounded, then the problems under consideration are not approximable within $\log^{1-ε} K$ for any $ε>0$ unless NP $\subseteq$ DTIME$(n^{\mathrm{poly} \log n})$, where $K$ is the number o

M. Teodoro, A. Damineli, R. G. Sharp, J. H. Groh

This work presents the first integral field spectroscopy of the Homunculus nebula around Eta Carinae in the near-infrared spectral region (J band). We confirmed the presence of a hole on the polar region of each lobe, as indicated by previous near-IR long-slit spectra and mid-IR images. The holes can be described as a cylinder of height (i.e. the thickness o

Ariel Megevand

The walls of bubbles in a first-order phase transition can propagate either as detonations, with a velocity larger than the speed of sound, or deflagrations, which are subsonic. We calculate the gravitational radiation that is produced by turbulence during a phase transition which develops via deflagration bubbles. We take into account the fact that a deflag

Sebastian Linden, Jean-Marc Virey

We test the robustness and flexibility of the Chevallier-Polarski-Linder (CPL) parameterization of the Dark Energy equation of state $w(z)=w_0+w_a \frac{z}{1+z}$ in recovering a four-parameter step-like fiducial model. We constrain the parameter space region of the underlying fiducial model where the CPL parameterization offers a reliable reconstruction. It

Sylvain Combrie', Alfredo De Rossi, Quynh Vy Tran, Henri Benisty

We have realized and measured a GaAs nanocavity in a slab photonic crystal based on the design by Kuramochi et al. [Appl. Phys.Lett., \textbf{88}, 041112, (2006)]. We measure a quality factor Q=700,000, which proves that ultra-high Q nanocavities are also feasible in GaAs. We show that, due to larger two-photon absorption (TPA) in GaAs, nonlinearities appear

Maulik K. Parikh, Jan Pieter van der Schaar

We formulate the information paradox in de Sitter space in terms of the no-cloning principle of quantum mechanics. We show that energy conservation puts an upper bound on the maximum entropy available to any de Sitter observer. Combined with a general result on the average information in a quantum subsystem, this guarantees that an observer in de Sitter spac

R. U. Abbasi, T. Abu-Zayyad, M. Allen, J. F. Amman

We have searched for correlations between the pointing directions of ultrahigh energy cosmic rays observed by the High Resolution Fly's Eye experiment and Active Galactic Nuclei (AGN) visible from its northern hemisphere location. No correlations, other than random correlations, have been found. We report our results using search parameters prescribed by

Bertrand Eynard

The generating function which counts partitions with the Plancherel measure (and its q-deformed version), can be rewritten as a matrix integral, which allows to compute its asymptotic expansion to all orders. There are applications in statistical physics of growing/melting crystals, T.A.S.E.P., and also in algebraic geometry. In particular we compute the Gro

Hengyi Xu, T. Heinzel, M. Evaldsson, I. V. Zozoulenko

A theoretical study of the transport properties of zigzag and armchair graphene nanoribbons with a magnetic barrier on top is presented. The magnetic barrier modifies the energy spectrum of the nanoribbons locally, which results in an energy shift of the conductance steps towards higher energies. The magnetic barrier also induces Fabry-Perot type oscillation

F. Castelli, I. Boscolo, S. Cialdi, M. G. Giammarchi

Antihydrogen production by charge exchange reaction between Positronium (Ps) atoms and antiprotons requires an efficient excitation of Ps atoms up to high-n levels (Rydberg levels). In this study it is assumed that a Ps cloud is produced within a relatively strong uniform magnetic field (1 Tesla) and with a relatively high temperature (100 K). Consequently,

I. M. Suslov

Reconstruction of the β-function for ϕ^4 theory, attempted previously by summation of perturbation series, leads to asymptotics β(g)=β_\infty g^αat g\to\infty, where α\approx 1 for space dimensions d=2,3,4. The natural hypothesis arises, that asymptotic behavior is β(g) \sim g for all d. Consideration of the zero-dimensional case confirms the hypothesis and

Alexander Jurisch, Jan-Michael Rost

We develop a quasi-analytical theory for the quantum reflection amplitude of Bose-Einstein condensates. We derive and calculate the decay-width of a Bose-Einstein condensate. A general relation between the time-dependent decay-law of the system and its quantum reflection amplitude allows us to explain the quantum reflection anomaly of Bose-Einstein condensat

S. Nicolosi, P. Ferrante, G. Schiaccianoce, G. Rizzo

In this paper we have considered the interaction of a Jaynes and Cummings system with the electromagnetic field in its vacuum state and, solving the dynamical problem, we have analyzed the amount of entanglement induced in the bipartite system (atom + cavity mode) by the common electromagnetic reservoir. This has allowed us to quantitatively characterize the

Mark Behrens

We characterize the 2-line of the p-local Adams-Novikov spectral sequence in terms of modular forms satisfying a certain explicit congruence condition for primes p > 3. We give a similar characterization of the 1-line, reinterpreting some earlier work of A. Baker and G. Laures. These results are then used to deduce that, for l a prime which generates the p-a

John Ardelius, Lenka Zdeborová

We study geometrical properties of the complete set of solutions of the random 3-satisfiability problem. We show that even for moderate system sizes the number of clusters corresponds surprisingly well with the theoretic asymptotic prediction. We locate the freezing transition in the space of solutions which has been conjectured to be relevant in explaining

Damien Gaboriau

We show that every non-amenable free product of groups admits free ergodic probability measure preserving actions which have relative property (T) in the sense of S.-Popa \cite[Def. 4.1]{Pop06}. There are uncountably many such actions up to orbit equivalence and von Neumann equivalence, and they may be chosen to be conjugate to any prescribed action when res

Valeria M. Rosa, Patricio S. Letelier

The existence and stability closed timelike curves in a Bonnor-Ward spacetime without torsion line singularities is shown by exhibiting particular examples.

Wei-Cheng Lee, A. H. MacDonald

Extensive ARPES and low-energy inelastic neutron scattering studies of cuprate superconductors can be successfully described using a weak-coupling theory in which quasiparticles on a square lattice interact via scalar and spin-dependent effective interactions. In this article we point out that in Bi$_2$Sr$_2$Ca$_{1-x}$Y$_x$Cu$_2$O$_8$ (Bi2212) both probes ar

Michael Urban, Peter Schuck

We study the pair-breaking effect of rotation on a cold Fermi gas in the BCS-BEC crossover region. In the framework of BCS theory, which is supposed to be qualitatively correct at zero temperature, we find that in a trap rotating around a symmetry axis, three regions have to be distinguished: (A) a region near the rotational axis where the superfluid stays a

Tae-Wan Noh, Mun Dae Kim, H. -S. Sim

We propose a scheme for a phase qubit in an SIFIS junction, consisting of bulk superconductors (S), a proximity-induced ferromagnet (F), and insulating barriers (I). The qubit state is constituted by 0 and $π$ phase states of the junction, in which the charging energy of the junction leads to the superposition of the two states. The qubit is operated by the

Vladimir Azarin

We approximate a chain recurrent dynamical system by periodic dynamical systems. This is similar to the well known Bohr theorem on approximation of almost periodic functions by periodic functions.

T. Gastine, B. Dintrans

Context: We study the kappa-mechanism that excites radial oscillations in Cepheid variables. Aims: We address the mode couplings that manages the nonlinear saturation of the instability in direct numerical simulations (DNS). Methods: We project the DNS fields onto an acoustic subspace built from the regular and adjoint eigenvectors that are solutions to the

John Lott

We show that a certain entropy-like function is convex, under an optimal transport problem that is adapted to Ricci flow. We use this to reprove the monotonicity of Perelman's reduced volume.

W. Weber, L. E. Golub, S. N. Danilov, J. Karch

Photogalvanic effects are observed and investigated in wurtzite (0001)-oriented GaN/AlGaN low-dimensional structures excited by terahertz radiation. The structures are shown to represent linear quantum ratchets. Experimental and theoretical analysis exhibits that the observed photocurrents are related to the lack of an inversion center in the GaN-based heter

Martin Panak, Vojtech Zadnik

The notion of special symplectic connections is closely related to contact parabolic geometries due to the work of M. Cahen and L. Schwachhöfer. We remind their characterization and reinterpret the result in terms of generalized Weyl connections. The aim of this paper is to provide an alternative and more explicit construction of special symplectic connectio

Raphael Hunger, Michael Joham

We prove convexity of the sum-power constrained mean square error (MSE) region in case of two single-antenna users communicating with a multi-antenna base station. Due to the MSE duality this holds both for the vector broadcast channel and the dual multiple access channel. Increasing the number of users to more than two, we show by means of a simple counter-

Shaaban Khalil, Osamu Seto

Sterile right-handed neutrinos can be naturally embedded in a low scale gauged $U(1)_{B-L}$ extension of the standard model. We show that, within a low reheating scenario, such a neutrino is an interesting candidate for dark matter. We emphasize that if the neutrino mass is of order of MeV, then it accounts for the measured dark matter relic density and also

V. P. Neznamov

The paper describes conditions for transformation from the Dirac representation to the Foldy-Wouthuysen representation. The necessary condition is the block-diagonal transformation of Hamiltonian relative to the upper and lower components of the wave function. The sufficient condition is the wave function transformation law described by relation (6). It has

Kumiko Hattori, Tetsuya Hattori

We give a unique classical solution to initial value problem for a system of partial differential equations for the densities of components of one dimensional incompressible fluid mixture driven by evaporation. Motivated by the known fact that the solution appears as an infinite particle limit of stochastic ranking processes, which is a simple stochastic mod

Daniel Krefl

We give an elementary introduction to the recent derivation of the effective low-energy gauge theories of D3-branes probing orientifolds of toric Calabi-Yau 3-fold singularities via brane tiling techniques.

Hugo Touchette

The theory of large deviations is concerned with the exponential decay of probabilities of large fluctuations in random systems. These probabilities are important in many fields of study, including statistics, finance, and engineering, as they often yield valuable information about the large fluctuations of a random system around its most probable state or t

I. Bejenari, V. Kantser

Electronic structure of bismuth telluride nanowires with the growth directions [110] and [015] is studied in the framework of anisotropic effective mass method using the parabolic band approximation. The components of the electron and hole effective mass tensor for six valleys are calculated for both growth directions. For a square nanowire, in the temperatu

Ariel G. Sanchez, Carlton M. Baugh, Raul Angulo

Oscillations in the baryon-photon fluid prior to recombination imprint different signatures on the power spectrum and correlation function of matter fluctuations. The measurement of these features using galaxy surveys has been proposed as means to determine the equation of state of the dark energy. The accuracy required to achieve competitive constraints dem

Kumiko Hattori, Tetsuya Hattori

We study a stochastic particle system which models the time evolution of the ranking of books by online bookstores (e.g., Amazon). In this system, particles are lined in a queue. Each particle jumps at random jump times to the top of the queue, and otherwise stays in the queue, being pushed toward the tail every time another particle jumps to the top. In an

J. Sieber, A. Gonzalez-Buelga, S. A. Neild, D. J. Wagg

We present a continuation method that enables one to track or continue branches of periodic orbits directly in an experiment when a parameter is changed. A control-based setup in combination with Newton iterations ensures that the periodic orbit can be continued even when it is unstable. This is demonstrated with the continuation of initially stable rotation

M. Revnivtsev, E. Churazov, S. Sazonov, W. Forman

We use deep Chandra observations to measure the emissivity of the unresolved X-ray emission in the elliptical galaxy NGC 3379. After elimination of bright, low-mass X-ray binaries with luminosities >10^{36 erg/sec, we find that the remaining unresolved X-ray emission is characterized by an emissivity per unit stellar mass L_x/M_stars ~8.2x10^{27} erg/s/M_sun

Birgit van Dalen

In this paper we prove several new stability results for the reconstruction of binary images from two projections. We consider an original image that is uniquely determined by its projections and possible reconstructions from slightly different projections. We show that for a given difference in the projections, the reconstruction can only be disjoint from t

Anna Campbellova, Rikard von Unge

We study monopole solutions of the quantum exact low-energy effective N=2 super Yang-Mills theories of Seiberg and Witten. We find a first order differential equation for the spatial dependence of the moduli and show that it can be interpreted as an attractor equation. Numerically integrating this equation, we try to address the question of what happens when

J. P. Rodriguez, P. N. Barnes, C. V. Varanasi

The results of a linear elasticity analysis yields that nano-rod inclusions aligned along the c axis of a thin film of YBa2Cu3O{7-delta}, such as BaZrO3 and BaSnO3, squeeze that matrix by pure shear. The sensitivity of the superconducting critical temperature in that material to the latter implies that the phase boundary separating the nano-rod inclusion fro

Valeriy A. Yumaguzhin

In this paper, we investigate the action of pseudogroup of all point transformations on the natural bundle of equations $y'' = u^0(x,y) + u^1(x,y)y' + u^2(x,y)(y')^2 + u^3(x,y)(y')^3$. We calculate the 1-st nontrivial differential invariant of this action. It is a horizontal differential 2-form with values in some algebra, it is defined o

Cuiling Luo

Using the skew-symmetry of the differential operators and multiplication operators in the canonical representations of finite-dimensional classical Lie algebras, we obtain some noncanonical polynomial representations of the classical Lie algebras. The representation spaces of all polynomials are decomposed into irreducible submodules, which are infinite-dime

Yun Soo Myung, Yong-Wan Kim, Young-Jai Park

We show that all thermodynamic quantities of the Einstein-Born-Infeld black holes in three dimensions can be obtained from the dilaton and its potential of two dimensional dilaton gravity through the dimensional reduction. These are all between non-rotating uncharged BTZ black hole (NBTZ) and charged BTZ black hole (CBTZ).

Costas Strouthos, John B. Kogut

Non-compact three-dimensional QED is studied by computer simulations to understand its chiral symmetry breaking features for different values of the number of fermion flavors N_f. We consider the four-component formulation for the fermion fields, which arises naturally as the continuum limit of the staggered fermion construction in (2+1) dimensions. We prese

Yongqin Liu

In this paper we focus on the global-in-time existence and the pointwise estimates of solutions to the initial value problem for the semilinear dissipative wave equation in multi-dimensions. By using the method of Green function combined with the energy estimates, we obtain the pointwise estimates of the solution.

Alessandro B. Romeo, Oscar Agertz, Ben Moore, Joachim Stadel

The effects of particle discreteness in N-body simulations of Lambda Cold Dark Matter (LambdaCDM) are still an intensively debated issue. In this paper we explore such effects, taking into account the scatter caused by the randomness of the initial conditions, and focusing on the statistical properties of the cosmological density field. For this purpose, we

Mitsuyoshi Yukawa, Ryuji Ukai, Peter van Loock, Akira Furusawa

Continuous-variable Gaussian cluster states are a potential resource for universal quantum computation. They can be efficiently and unconditionally built from sources of squeezed light using beam splitters. Here we report on the generation of three different kinds of continuous-variable four-mode cluster states. In our realization, the resulting cluster-type

R. N. Bisset, M. J. Davis, T. P. Simula, P. B. Blakie

We simulate a trapped quasi-two-dimensional Bose gas using a classical field method. To interpret our results we identify the uniform Berezinskii-Kosterlitz-Thouless (BKT) temperature $T_{BKT}$ as where the system phase space density satisfies a critical value. We observe that density fluctuations are suppressed in the system well above $T_{BKT}$ when a quas

Giuseppe La Vacca, Loris P. L. Colombo, Luca Vergani, Silvio A. Bonometto

When CMB data are used to derive cosmological parameters, their very choice does matter: some parameter values can be biased if the parameter space does not cover the "true" model. This is a problem, because of the difficulty to parametrize Dark Energy (DE) physics. We test this risk through numerical experiments. We create artificial data for dynami

Fusun Akman

Sudoku grids can be thought of as graphs where the vertices are the squares of the grid, and edges join vertices in the same row, column, or sub-grid. A Sudoku puzzle corresponds to a partial proper coloring of the Sudoku graph. We provide a new and simpler proof of the theorem which states that the number of completions of partial colorings of a graph is a

Corey A. Hoelscher

This paper has been withdrawn by the author due to a critical error in the proof of Theorem A pointed out by Burkhard Wilking.

Masahide Sasaki, Masahiro Takeoka, Hiroki Takahashi

We study non-Gaussian states generated by two-photon subtraction from a cw squeezed light source. In a cw scheme one can subtract two photons from the source with a designated time separation and can genarate temporally multiplexed superposition states of continuous variables. We numerically study the properties of these states in the light of bosonic interf

Ping Wang, Chaoming Song, Christopher Briscoe, Hernan A. Makse

We report experimental measurements of particle dynamics on slowly sheared granular matter in a three-dimensional (3D) Couette cell. A closely-packed ensemble of transparent spherical beads is confined by an external pressure and filled with fluid to match both the density and refractive index of the beads. This allows us to track tracer particles embedded i

Stanislaw Mrowczynski

Coupling of the quark-gluon plasma from the early stage of heavy-ion collisions is argued to be weaker at LHC than at RHIC. For this reason, the role of instabilities - the pre-equilibrium plasma is unstable with respect to chromomagnetic modes - will be enhanced. The instabilities isotropize the system and speed up the process of equilibration. A possibilit

Yue Zhang, Haipeng An, Xiangdong Ji, Rabindra N. Mohapatra

We show that in supersymmetric left-right models (SUSYLR), the upper bound on the lightest neutral Higgs mass can be appreciably higher than that in minimal supersymmetric standard model (MSSM). The exact magnitude of the bound depends on the scale of parity restoration and can be 10-20 GeV above the MSSM bound if mass of the right-handed gauge boson $W_R$ i

Alwen Tiu, Rajeev Gore

We consider the problem of intruder deduction in security protocol analysis: that is, deciding whether a given message $M$ can be deduced from a set of messages $Γ$ under the theory of blind signatures and arbitrary convergent equational theories modulo associativity and commutativity (AC) of certain binary operators. The traditional formulations of intruder

Yaron Ostrover, Ilya Tyomkin

In this paper we study certain algebraic properties of the quantum homology algebra for the class of symplectic toric Fano manifolds. In particular, we examine the semi-simplicity of the quantum homology algebra, and the more general property of containing a field as a direct summand. Our main result provides an easily-verified sufficient condition for these

J. Wang, L. Cywinski, C. Sun, J. Kono

We have studied ultrafast photoinduced demagnetization in GaMnAs via two-color time-resolved magneto-optical Kerr spectroscopy. Below-bandgap midinfrared pump pulses strongly excite the valence band, while near-infrared probe pulses reveal sub-picosecond demagnetization that is followed by an ultrafast ($\sim$1 ps) partial recovery of the Kerr signal. Throug

Steven N. Evans, Alex Gottlieb

As well as arising naturally in the study of non-intersecting random paths, random spanning trees, and eigenvalues of random matrices, determinantal point processes (sometimes also called fermionic point processes) are relatively easy to simulate and provide a quite broad class of models that exhibit repulsion between points. The fundamental ingredient used

L. O. Sjouwerman, Y. M. Pihlstrom

We present Very Large Array (VLA) radio interferometry observations of the 1720 MHz OH masers in the Galactic Center (GC). Most 1720 MHz OH masers arise in regions where the supernova remnant Sgr A East is interacting with the interstellar medium. The majority of the newly found 1720 MHz OH masers are located to the northeast, independently indicating and co

Sean M. Andrews, A. M. Hughes, D. J. Wilner, Chunhua Qi

We present high spatial resolution (< 0.3&#34; = 40$ AU) Submillimeter Array observations of the 865 micron continuum emission from the circumstellar disk around the young star DoAr 25. Despite its bright millimeter emission, this source exhibits only a comparatively small infrared excess and low accretion rate, suggesting that the material and structural pr

E. Garcia-Rio, P. Gilkey, M. E. Vazquez-Abal, R. Vazquez-Lorenzo

In the algebraic context, we show that null Osserman, spacelike Osserman, and timelike Osserman are equivalent conditions for a model of signature (2,2). We also classify the null Jordan Osserman models of signature (2,2). In the geometric context, we show that a pseudo-Riemannian manifold of signature (2,2) is null Jordan Osserman if and only if either it h

Matthew G. Baring, Alice K. Harding

The paradigm for Anomalous X-ray Pulsars (AXPs) has evolved recently with the discovery by INTEGRAL and RXTE of flat, hard X-ray components in three AXPs. These non-thermal spectral components differ dramatically from the steeper quasi-power-law tails seen in the classic X-ray band in these sources, and can naturally be attributed to activity in the magnetos

M. Moskalets, M. Buttiker

We calculate analytically the Floquet scattering matrix for a periodically driven double-barrier structure. Our approach takes into account dynamical effects which become necessarily important when electrons propagate through a system subject to a fast drive. It is convenient to represent the Floquet scattering amplitude as a sum of amplitudes corresponding

Jeno Szigeti, Leon van Wyk

We have results about the centralizer.

Giacomo Cacciapaglia, Guido Marandella, John Terning

We examine the correspondence between the anti-de Sitter (AdS) description of conformal field theories (CFTs) and the unparticle description of CFTs. We show how unparticle actions are equivalent to holographic boundary actions for fields in AdS, and how massive unparticles provide a new type of infrared cutoff that can be simply implemented in AdS by a soft

Daniel de Florian, Rodolfo Sassot, Marco Stratmann, Werner Vogelsang

We present a new analysis of the helicity parton distributions of the nucleon. The analysis takes into account the available data from inclusive and semi-inclusive polarized deep inelastic scattering, as well as from polarized pp scattering at RHIC. For the first time, all theoretical calculations are performed fully at next-to-leading order (NLO) of perturb

E. L. Starostin, G. H. M. van der Heijden

We study the non-monotonic force-extension behaviour of helical ribbons using a new model for inextensible elastic strips. Unlike previous rod models our model predicts hysteresis behaviour for low-pitch ribbons of arbitrary material properties. Associated with it is a first-order transition between two different helical states as observed in experiments wit

A. L. Pirozerski, S. E. Emelin

In the present paper kinetics of emission spectra of the high voltage erosive water discharge at near ultraviolet and visible spectral ranges has been investigated. Obtained results show a similarity of physical properties of this discharge (and of corresponding plasmoids) to that of some other types of erosional discharges which also result in the formation

Alessandro Curioni, Bonnie T. Fleming, Mitchell Soderberg

In this paper we give a thorough description of a liquid argon time projection chamber designed, built and operated at Yale. We present results from a calibration run where cosmic rays have been observed in the detector, a first in the US.

Jacopo Stoppa

We introduce a cohomological obstruction to solving the constant scalar curvature Kähler (cscK) equation twisted by a semipositive form, appearing in works of Fine and Song-Tian. Geometrically this gives an obstruction for a manifold to be the base of a holomorphic submersion carrying a cscK metric in certain ``adiabatic&#39;&#39; classes. In turn this produ

Antal Jevicki, Kewang Jin

In this contribution we describe some soliton based techniques for generating classical AdS string solutions. The methods introduced are useful for further understanding of rotating AdS configurations with spikes which correspond to higher twist operators in SYM theory. The main identification (accomplished in arXiv:0712.1193) between solitons and string spi

Isabelle A. Grenier

The exclusive Galactic gamma-ray club has opened up to new members. Supernova remnants, pulsar wind nebulae, and massive binary systems hosting a compact object have recently joined the young pulsars as firmly established sources of gamma rays in the Milky Way. Massive young stellar clusters are on the waiting list to join the club. Only the fine imaging rec

J. Sieber, P. Kowalczyk, S. J. Hogan, M. di Bernardo

We study dynamical systems that switch between two different vector fields depending on a discrete variable and with a delay. When the delay reaches a problem-dependent critical value so-called event collisions occur. This paper classifies and analyzes event collisions, a special type of discontinuity induced bifurcations, for periodic orbits. Our focus is o

Igor Cialenco, Sergey Lototsky, Jan Pospisil

A parameter estimation problem is considered for a diagonaliazable stochastic evolution equation using a finite number of the Fourier coefficients of the solution. The equation is driven by additive noise that is white in space and fractional in time with the Hurst parameter $H\geq 1/2$. The objective is to study asymptotic properties of the maximum likeliho

Ulysse Marboeuf, Olivier Mousis, David Ehrenreich, Yann Alibert

We study the formation conditions of icy planetesimals in protoplanetary disks in order to determine the composition of ices in small and cold extrasolar planets. Assuming that ices are formed from hydrates, clathrates, and pure condensates, we calculate their mass fractions with respect to the total quantity of ices included in planetesimals, for a grid of

Oleg V. Yazyev, Alfredo Pasquarello

Using first principles calculations, we model the chemical vapor deposition (CVD) growth of carbon nanotubes (CNT) on nanoparticles of late transition (Ni, Pd, Pt) and coinage (Cu, Ag, Au) metals. The process is analyzed in terms of the binding of mono- and diatomic carbon species, their diffusion pathways, and the stability of the growing CNT. We find that

James M. Stone, Thomas A. Gardiner, Peter Teuben, John F. Hawley

A new code for astrophysical magnetohydrodynamics (MHD) is described. The code has been designed to be easily extensible for use with static and adaptive mesh refinement. It combines higher-order Godunov methods with the constrained transport (CT) technique to enforce the divergence-free constraint on the magnetic field. Discretization is based on cell-cente

T. Pardini, R. R. P. Singh, A. Katanin, O. P. Sushkov

Using series expansions and spin-wave theory we calculate the spin-stiffness anisotropy $ρ_{sx}/ρ_{sy}$ in Heisenberg models on the square lattice with anisotropic couplings $J_x,J_y$. We find that for the weakly anisotropic spin-half model ($J_x\approx J_y$), $ρ_{sx}/ρ_{sy}$ deviates substantially from the naive estimate $ρ_{sx}/ρ_{sy} \approx J_x/J_y$. We

Roman Frigg

This is an extensive review of recent work on the foundations of statistical mechanics. Subject matters discussed include: interpretation of probability, typicality, recurrence, reversibility, ergodicity, mixing, coarse graining, past hypothesis, reductionism, phase average, thermodynamic limit, interventionism, entropy.

A. Bressan, F. Rampazzo

The paper analyzes a Lagrangian system which is controlled by directly assigning some of the coordinates as functions of time, by means of frictionless constraints. In a natural system of coordinates, the equations of motions contain terms which are linear or quadratic w.r.t.time derivatives of the control functions. After reviewing the basic equations, we e

Lorenzo Brandolese

Given a finite sequence of times $0<t_1<...<t_N$, we construct an example of a smooth solution of the free nonstationnary Navier--Stokes equations in $\R^d$, $d=2,3$, such that: (i) The velocity field $u(x,t)$ is spatially poorly localized at the beginning of the evolution but tends to concentrate until, as the time $t$ approaches $t_1$, it becomes well-loca

T. Klimczuk, Han-oh Lee, F. Ronning, T. Durakiewicz

We report the properties of two new isostructural compounds, U3Bi4Ni3 and U3Bi4Rh3. The first of these compounds is non-metallic, and the second is a nearly ferromagnetic metal, both as anticipated from their electron count relative to other U-based members of the larger 3-4-3 family. For U3Bi4Rh3, a logarithmic increase of C/T below 3 K, a resistivity propo

E. Kim, K. Stratford, R. Adhikari, M. E. Cates

We use lattice Boltzmann simulations to investigate the formation of arrested structures upon demixing of a binary solvent containing neutrally wetting colloidal particles. Previous simulations for symmetric fluid quenches pointed to the formation of `bijels&#39;: bicontinuous interfacially jammed emulsion gels. These should be created when a glassy monolaye

Juan Zhang, John E. Kolassa

In the manuscript, we present a practical way to find the matching priors proposed by Welch & Peers (1963) and Peers (1965). We investigate the use of saddlepoint approximations combined with matching priors and obtain p-values of the test of an interest parameter in the presence of nuisance parameter. The advantage of our procedure is the flexibility of cho

Elisa Tenni

Let $f:S \fr B$ be a surface fibration with fibres of genus 5. We find a linear relation between the fundamental invariants of the surface. Namely $K_f^2=χ_f+N$ where $N$ is the number of trigonal fibres. Our proof is based on the analysis of the relative canonical algebra $\cal{R}(f)$.

Rongwei Yang

For a tuple $A=(A_0, A_1, ..., A_n)$ of elements in a unital Banach algebra ${\mathcal B}$, its {\em projective spectrum} $p(A)$ is defined to be the collection of $z=[z_0, z_1, ..., z_n]\in \pn$ such that $A(z)=z_0A_0+z_1A_1+... +z_nA_n$ is not invertible in ${\mathcal B}$. The pre-image of $p(A)$ in ${\cc}^{n+1}$ is denoted by $P(A)$. When ${\mathcal B}$ i

P. Gori, F. Ronci, S. Colonna, A. Cricenti

The nature of the alpha-Sn/Ge(111) surface is still a matter of debate. In particular, two possible configurations have been proposed for the 3x3 ground state of this surface: one with two Sn adatoms in a lower position with respect to the third one (1U2D) and the other with opposite configuration (2U1D). By means of first-principles quasiparticle calculatio

Lalitha Sankar, Narayan B. Mandayam, H. Vincent Poor

The sum-capacity is studied for a K-user degraded Gaussian multiaccess relay channel (MARC) where the multiaccess signal received at the destination from the K sources and relay is a degraded version of the signal received at the relay from all sources, given the transmit signal at the relay. An outer bound on the capacity region is developed using cutset bo

Franz M. Weinert, Jonas A. Kraus, Thomas Franosch, Dieter Braun

The thermal expansion of a fluid combined with a temperature-dependent viscosity introduces nonlinearities in the Navier-Stokes equations unrelated to the convective momentum current. The couplings generate the possibility for net fluid flow at the microscale controlled by external heating. This novel thermo-mechanical effect is investigated for a thin fluid

David Berenstein

Recent progress towards understanding a strong coupling expansion for various superconformal field theories in four dimensions is described. First, the case of the maximally supersymmetric Yang Mills theory is analyzed, as well as many calculations that can be done directly at strong coupling and matched to the AdS dual geometry. Also, this understanding is

Frank C. Porter

Several approaches to testing the hypothesis that two histograms are drawn from the same distribution are investigated. We note that single-sample continuous distribution tests may be adapted to this two-sample grouped data situation. The difficulty of not having a fully-specified null hypothesis is an important consideration in the general case, and care is