August 2005 arXiv papers — page 4

Frank Harary, Wolfgang Slany, Oleg Verbitsky

We consider vertex colorings of graphs in which adjacent vertices have distinct colors. A graph is $s$-chromatic if it is colorable in $s$ colors and any coloring of it uses at least $s$ colors. The forcing chromatic number $F(G)$ of an $s$-chromatic graph $G$ is the smallest number of vertices which must be colored so that, with the restriction that $s$ col

Agostino Dovier, Enrico Pontelli, Gianfranco Rossi

The unification problem in algebras capable of describing sets has been tackled, directly or indirectly, by many researchers and it finds important applications in various research areas--e.g., deductive databases, theorem proving, static analysis, rapid software prototyping. The various solutions proposed are spread across a large literature. In this paper

L. -M. Duan

We derive the Hamiltonian for cold fermionic atoms in an optical lattice across a broad Feshbach resonance, taking into account of both multiband occupations and neighboring-site collisions. Under typical configurations, the resulting Hamiltonian can be dramatically simplified to an effective single-band model, which describes a new type of resonance between

D. E. MacLaughlin, M. S. Rose, O. O. Bernal, R. H. Heffner

Transverse-field muSR shifts and relaxation rates have been measured in the non-Fermi liquid (NFL) alloy system UCu_{5-x}Pt_x, x = 1.0, 1.5, and 2.5. At low temperatures the fractional spread in Knight shifts delta K/K approx deltachi/chi is gtrsim 2 for x = 1, but is only half this value for x = 1.5 and 2.5. In a disorder-driven scenario where the NFL behav

D. E. MacLaughlin, M. S. Rose, J. E. Anderson, O. O. Bernal

Longitudinal-field muon spin relaxation (LF-muSR) experiments have been performed in unannealed and annealed samples of the heavy-fermion compound UCu_4Pd to study the effect of disorder on non-Fermi liquid behavior in this material. The muon spin relaxation functions G(t,H) obey the time-field scaling relation G(t,H) = G(t/H^gamma) previously observed in th

Norman H. March, Alejandro Cabo, Francisco Claro

The measured melting curve $T_{m}(ν)$ between the crystal and liquid phases is analyzed using thermodynamics to extract the change of magnetization $ΔM$ as a function of the Landau level filling factor \ $ν,$ near $ν=1$. \ An explanation of $ΔM$($ν)$ is proposed \ in terms of Skyrmions. \ Near $ν=3$, a Wigner crystal is the most probable solid phase, experim

D. E. MacLaughlin, M. S. Rose, J. E. Anderson, Lei Shu

Longitudinal-field muon spin relaxation experiments have been carried out in the paramagnetic state of single-crystal Gd_2Ti_2O_7 just above the phase transition at T_m = 1.0 K. At high applied fields the exponential relaxation time T_1 is proportional to field, whereas T_1 saturates below a crossover field B_c that is ~2.5 T at 1.5 K and decreases as T_m is

Dimitris Achlioptas, Michael Molloy, Cristopher Moore, Frank Van Bussell

We provide an optimally mixing Markov chain for 6-colorings of the square lattice on rectangular regions with free, fixed, or toroidal boundary conditions. This implies that the uniform distribution on the set of such colorings has strong spatial mixing, so that the 6-state Potts antiferromagnet has a finite correlation length and a unique Gibbs measure at z

J. He, Z. Li, S. Zhang

By using the spin torque model in ferromagnets, we compare the response of vortex and transverse walls to the electrical current. For a defect-free sample and a small applied current, the steady state wall mobility is independent of the wall structure. In the presence of defects, the minimum current required to overcome the wall pinning potential is much sma

Z. Li, J. He, S. Zhang

When a spin-polarized current flows through a ferromagnet, the local magnetization receives a spin torque. Two consequences of this spin torque are studied. First, the uniformly magnetized ferromagnet becomes unstable if a sufficiently large current is applied. The characteristics of the instability include spin wave generation and magnetization chaos. Secon

Wolfhard Janke, Adriaan M. J. Schakel

The relation between critical exponents, characterizing a continuous phase transition, and the fractal structure of physical lines, proliferating at the critical point, is established by considering the two-dimensional O($N$) spin model for which many exact results are available.

L. S. Sharath Chandra, Kaustav Mukherjee, V. Ganesan, A. Banerjee

Field variation of heat capacity at fixed temperatures is investigated to identify the origin of the field induced first order phase transition in polycrystalline Ce(Fe$_{0.094}$Al$_{0.04}$)$_2$ sample. The heat capacity at 4.5K and 3.5K shows hysteresis in different field cycles and the virgin curve stays outside the envelope curve. This is analogous to the

Shaffique Adam, Mikhail L. Polianski, Piet W. Brouwer

A sufficiently large unpolarized current can cause a spin-wave instability in thin nanomagnets with asymmetric contacts. The dynamics beyond the instability is understood in the perturbative regime of small spin-wave amplitudes, as well as by numerically solving a discretized model. In the absence of an applied magnetic field, our numerical simulations revea

Atsushi Harada, Shinji Kawasaki, Hisashi Kotegawa, Yoshio Kitaoka

We report on a cooperative phenomenon of ferromagnetism and unconventional superconductivity (SC) in UGe$_2$ through the measurements of $^{73}$Ge nuclear-quadrupole-resonance (NQR) under pressure ($P$). The NQR spectra evidenced phase separation into ferromagnetic and paramagnetic phases in the vicinity of $P_c\sim 1.5$ GPa, pointing to a first-order transi

A. Brooks Harris

Ferroelectricity has been found to occur in several insulating systems, such as TbMnO$_3$ (TMO) and Ni$_3$V$_2$O$_8$ (NVO) which have more than one phase with incommensurately modulated long-range magnetic order. Here we give a phenomenological model which relates the symmetries of the magnetic structure as obtained from neutron diffraction to the developmen

G. Wendin, V. S. Shumeiko

This paper gives an introduction to the physics and principles of operation of quantized superconducting electrical circuits for quantum information processing.

Gert-Ludwig Ingold, Yu. V. Nazarov

1. Introduction 2. Description of the environment 3. Electron tunneling rates for single tunnel junctions 4. Examples of electromagnetic environments 5. Tunneling rates in Josephson junctions 6. Double junction and single electron transistor 7. Microscopic foundation

V. M. Silkin, J. M. Pitarke, E. V. Chulkov, P. M. Echenique

We have performed self-consistent calculations of the dynamical response of the (111) surface of the noble metals Cu, Ag, and Au. Our results indicate that the partially occupied surface-state band in these materials yields the existence of acoustic surface plasmons with linear dispersion at small wave vectors. Here we demonstrate that the sound velocity of

J. Minar, H. Ebert, C. De Nadai, N. B. Brookes

The pure Fano-effect in angle-integrated valence-band photo-emission of ferromagnets has been observed for the first time. A contribution of the intrinsic spin polarization to the spin polarization of the photo-electrons has been avoided by an appropriate choice of the experimental parameters. The theoretical description of the resulting spectra reveals a co

S. Ciliberti, M. Mezard, R. Zecchina

The use of parity-check gates in information theory has proved to be very efficient. In particular, error correcting codes based on parity checks over low-density graphs show excellent performances. Another basic issue of information theory, namely data compression, can be addressed in a similar way by a kind of dual approach. The theoretical performance of

Sergey Savel'ev, Valery Yampol'skii, Alexander Rakhmanov, Franco Nori

We propose how to control the THz radiation generated by fast moving Josephson vortices in spatially modulated (either along the c-axis or the ab-plane) samples of Bi-2212 and related superconducting compounds. We show that the JVs moving in a subset of weaker junctions can generate out-of-ab-plane and outside-the-cone Cherenkov radiation. The ab-plane modul

D. H. E. Gross

Simple example: During the sudden expansion of an isolated ideal gas from a small volume V_0 into a larger one V_1, the entropy changes by Delta S= N ln(V_1/V_0)=-beta Delta F>0 but no work W is produced nor absorbed. Consequently, Jarzynski&#39;s identity <exp(-beta W)>= exp(-beta Delta F) is wrong.

Antonio Rodriguez, Rudolf A. Roemer, Matthew S. Turner

We study electronic transport in long DNA chains using the tight-binding approach for a ladder-like model of DNA. We find insulating behavior with localizaton lengths xi ~ 25 in units of average base-pair seperation. Furthermore, we observe small, but significant differences between lambda-DNA, centromeric DNA, promoter sequences as well as random-ATGC DNA.

D. Ivaneyko, J. Ilnytskyi, B. Berche, Yu. Holovatch

We perform numerical simulations to study static and dynamic critical behaviour of the 3d random-site Ising model. A distinct feature of our approach is a combination of the Metropolis, Swendsen-Wang, and Wolff Monte Carlo algorithms. For the static critical behaviour, these approaches are the complementary ones, whereas in dynamics they correspond to three

H. Rafii-Tabar, H. R. Sepangi

The stochastic dynamics of inclusions in a randomly fluctuating biomembrane is simulated. These inclusions can represent the embedded proteins and the external particles arriving at a cell membrane. The energetics of the biomembrane is modelled via the Canham-Helfrich Hamiltonian. The contributions of both the bending elastic-curvature energy and the surface

P. Pingue, V. Piazza, P. Baschieri, C. Ascoli

The fabrication and performances of cantilevered probes with reduced parasitic capacitance starting from a commercial Si3N4 cantilever chip is presented. Nanomachining and metal deposition induced by focused ion beam techniques were employed in order to modify the original insulating pyramidal tip and insert a conducting metallic tip. Two parallel metallic e

Sergey Savel&#39;ev, Valery Yampol&#39;skii, Franco Nori

We predict the existence of surface waves in layered superconductors in the THz frequency range, below the Josephson plasma frequency $ω_J$. This wave propagates along the vacuum-superconductor interface and dampens in both transverse directions out of the surface (i.e., towards the superconductor and towards the vacuum). This is the first prediction of prop

Sergey Savel&#39;ev, Valery Yampol&#39;skii, Alexander Rakhmanov, Franco Nori

We show that a moving Josephson vortex in spatially modulated layered superconductors generates out-of-plane THz radiation. Remarkably, the magnetic and in-plane electric fields radiated are of the same order, which is very unusual for any good-conducting medium. Therefore, the out-of-plane radiation can be emitted to the vacuum without the standard impedanc

Lorenzo Malavasi, Carla Sanna, Nathascia Lampis, Alessandra Geddo Lehmann

In this paper we reported, to the best of our knowledge, the first deposition of highly oriented thin films (with thickness of about 90 nm) of NdCoO3 and Nd0.8Sr0.2CoO3 cobaltites on single-crystalline STO and LAO substrates. Our investigation has shown that highly oriented single phase thin films of NCO and NSCO can be successfully deposited by means of rf-

A. Kalitsov, I. Theodonis, N. Kioussis, M. Chshiev

We present tight-binding calculations of the spin torque in non-collinear magnetic tunnel junctions based on the non-equilibrium Green functions approach. We have calculated the spin torque via the effective local magnetic moment approach and the divergence of the spin current. We show that both methods are equivalent, i.e. the absorption of the spin current

Th. Gerrits, M. L. Schneider, A. B. Kos, T. J. Silva

A time-resolved ferromagnetic resonance technique was used to investigate the magnetization dynamics of a 10 nm thin Permalloy film. The experiment consisted of a sequence of magnetic field pulses at a repetition rate equal to the magnetic systems resonance frequency. We compared data obtained by this technique with conventional pulsed inductive microwave ma

Markus Mueller, Eran Lebanon

We discuss the history dependence and memory effects which are observed in the out-of-equilibrium conductivity of electron glasses. The experiments can be understood by assuming that the local density of states retains a memory of the sample history. We provide analytical arguments for the consistency of this assumption, and discuss the saturation of the mem

A. Astillero, A. Santos

In the preceding paper (cond-mat/0405252), we have conjectured that the main transport properties of a dilute gas of inelastic hard spheres (IHS) can be satisfactorily captured by an equivalent gas of elastic hard spheres (EHS), provided that the latter are under the action of an effective drag force and their collision rate is reduced by a factor $(1+α)/2$

A. Kwang-Hua Chu

We make an estimate of the possible range of $ΔT_c$ induced by high-pressure effects in post-metallic superconductors by using the theory of {\it extended irreversible/reversible thermodynamics} and Pippard&#39;s length scale. The relationship between the increment of the superconducting temperature and the increase of the pressure is parabolic.

A. M. Ghez, S. D. Hornstein, J. Lu, A. Bouchez

(Abridged) We present the first Laser Guide Star Adaptive Optics (LGS-AO) observations of the Galactic center. LGS-AO has dramatically improved the quality, robustness, and versatility with which high angular resolution infrared images of the Galactic center can be obtained with the W. M. Keck II 10-meter telescope. Specifically, Strehl ratios of 0.7 and 0.3

A. Del Popolo, N. Ercan

In this paper, I revisit the constraints obtained by several authors (Reichart et al. 1999; Eke et al. 1998; Henry 2000) on the estimated values of $Ω_{\rm m}$, $n$ and $σ_8$ in the light of recent theoretical developments: 1) new theoretical mass functions (Sheth & Tormen 1999, Sheth, Mo & Tormen 2001, Del Popolo 2002b); 2) a more accurate mass-temperature

Andrew N. Youdin

We show that small solids in low mass, turbulent protoplanetary disks collect into self-gravitating rings. Growth is faster than disk lifetimes and radial drift times for moderately strong turbulence, characterized by dimensionless diffusivities, $α_g < 10^{-6} -- 10^{-3}$ when particles are mm-sized. This range reflects a strong dependance on disk models. G

Q. D. Wang, Y. Yao, T. M. Tripp, T. -T. Fang

X-ray absorption lines of highly-ionized species such as OVII at about zero redshift have been firmly detected in the spectra of several active galactic nuclei. However, the location of the absorbing gas remains a subject of debate. To separate the Galactic and extragalactic contributions to the absorption, we have obtained Chandra LETG-HRC and FUSE observat

Curtis Struck, Michele Kaufman, Elias Brinks, Magnus Thomasson

We present numerical hydrodynamical models of the collision between the galaxies IC 2163 and NGC 2207. These models extend the results of earlier work where the galaxy discs were modeled one at a time. We confirm the general result that the collision is primarily planar, that is, at moderate inclination relative to the two discs, and prograde for IC 2163, bu

Andrew N. Youdin

We analyze the gravitational collapse of solids subject to gas drag in a protoplanetary disk. We also study the stirring of solids by turbulent fluctuations to determine the velocity dispersion and thickness of the midplane particle layer. The usual thresholds for determining gravitational instability in disks, Toomre&#39;s criterion and/or the Roche density

Sergiy Silich, Guillermo Tenorio-Tagle, Gabriel Alejandro Anorve Zeferino

The X-ray emission properties from the hot thermalized plasma that results from the collisions of individual stellar winds and supernovae ejecta within rich and compact star clusters are discussed. We propose a simple analytical way of estimating the X-ray emission generated by super star clusters and derive an expression that indicates how this X-ray emissi

Tohru Nagao, Roberto Maiolino, Alessandro Marconi

We analyze optical (UV rest-frame) spectra of X-ray selected narrow-line QSOs at redshift 1.5 < z < 3.7 found in the Chandra Deep Field South and of narrow-line radio galaxies at redshift 1.2 < z < 3.8 to investigate the gas metallicity of the narrow-line regions and their evolution in this redshift range. Such spectra are also compared with UV spectra of lo

James Fisher, Klaus-Peter Schröder, Robert Connon Smith

We study a sample of spectroscopic binaries (SBs) in the local solar neighbourhood to 100 pc and to an absolute magnitude of 4 in an attempt to find the distributions of the period, primary mass and the mass ratio as well as the IMF of the local population of field binaries. The sample was collated using available SB data and the Hipparcos catalogue, the lat

P. B. Stetson, M. Catelan, H. A. Smith

New BVRI broad-band photometry and astrometry are presented for the globular cluster NGC 4147, based upon measurements derived from 524 ground-based CCD images mostly either donated by colleagues or retrieved from public archives. We have also reanalysed five exposures of the cluster obtained with WFPC2 on the Hubble Space Telescope in the F439W and F555W (B

Craig J. Copi, Lawrence M. Krauss, David Simmons-Duffin, Steven R. Stroiney

The future of direct terrestrial WIMP detection lies on two fronts: new, much larger low background detectors sensitive to energy deposition, and detectors with directional sensitivity. The former can large range of WIMP parameter space using well tested technology while the latter may be necessary if one is to disentangle particle physics parameters from as

Paul J. McMillan, Walter Dehnen

Angular momentum transfer from a rotating stellar bar has been proposed by Weinberg & Katz (2002) as a mechanism to destroy dark-matter cusps in a few rotation periods. The N-body simulations performed by these authors in support of their claim employed spherical harmonics for the force computation and were, as shown by Sellwood (2003), very sensitive to inc

J. Jurcsik, B. Szeidl, M. Váradi, A. Henden

Based on extended multicolour CCD photometry of the triple-mode radial pulsator V823 Cas we studied the properties of the coupling frequencies invoked by nonlinear processes. Our results support that a resonance connection as suggested by Antonello & Aikawa (1998) affects the mode coupling behaviour. The P1/P0 period ratio of V823 Cas has an &#34;out of rang

V. Holzwarth, M. Jardine

Observational and theoretical investigations provide evidence for non-uniform spot and magnetic flux distributions on rapidly rotating stars, which have a significant impact on their angular momentum loss rate through magnetised winds. Supplementing the formalism of MacGregor & Brenner (1991) with a latitude-dependent magnetised wind model, we analyse the ef

Nigel G. Douglas

This review attempts to place the observations of extragalactic planetary nebulae in the context of galactic dynamics. From this point of view only the radial velocities of the PNe are important. We have built a specialised instrument to detect PNe in distant galaxies and measure their radial velocities in one step. This is explained in some detail, along wi

S. Pires, J. B. Juin, D. Yvon, Y. Moudden

We present a new method for the reconstruction of Sunyaev-Zel&#39;dovich (SZ) galaxy clusters in future SZ-survey experiments using multiband bolometer cameras such as Olimpo, APEX, or Planck. Our goal is to optimise SZ-Cluster extraction from our observed noisy maps. We wish to emphasize that none of the algorithms used in the detection chain is tuned on pr

Radoslaw Wojtak, Ewa L. Lokas, Stefan Gottloeber, Gary A. Mamon

Using cosmological N-body simulations we study the line-of-sight velocity distribution of dark matter haloes focusing on the lowest-order even moments, dispersion and kurtosis, and their application to estimate the mass profiles of cosmological structures. For each of the ten massive haloes selected from the simulation box we determine the virial mass, conce

S. Orlando, G. Peres, F. Reale, F. Bocchino

We model the hydrodynamic interaction of a shock wave of an evolved supernova remnant with a small interstellar gas cloud like the ones observed in the Cygnus loop and in the Vela SNR. We investigate the interplay between radiative cooling and thermal conduction during cloud evolution and their effect on the mass and energy exchange between the cloud and the

R. J. Beswick, S. Aalto, A. Pedlar, S. Huttemeister

We present sub-arcsecond, Multi-Element Radio Linked Interferometer (MERLIN) observations of the decimetre radio continuum structure and neutral hydrogen (HI) absorption from the nuclear region of the starburst galaxy NGC 4194 (the Medusa Merger). The continuum structure of the central kiloparsec of the Medusa has been imaged, revealing a pair of compact rad

J. Kasparova, M. Karlicky, E. P. Kontar, R. A. Schwartz

A multi-wavelength spatial and temporal analysis of solar high energy electrons is conducted using the August 20, 2002 flare of an unusually flat (gamma=1.8) hard X-ray spectrum. The flare is studied using RHESSI, Halpha, radio, TRACE, and MDI observations with advanced methods and techniques never previously applied in the solar flare context. A new method

HongSheng Zhao

Many past attempts to kill MOND have only strengthened the theory. Better data on galaxy velocity curves clearly favor MOND (without fine-tuning) over cold dark matter. The usual critism on the incompleteness of classical MOND has spurred a Modified Relativity (MR) by Bekenstein. After outlining cosmology and lensing in MOND, we review MOND on small scales.

Fenghui Zhang, Lifang Li, Zhanwen Han

Using EPS we present high resolution (0.3 Å, HRes) ISEDs from 3000 to 7000 Åand Lick/IDS absorption-line indices, for an extensive set of instantaneous burst binary stellar populations (BSPs) with binary interactions. The ages of the BSPs are in the range 1 - 15 Gyr and the metallicities are in the range 0.004 - 0.03. This HRes synthesis results can satisfy

M. E. Brown, C. A. Trujillo, D. L. Rabinowitz

We present the discovery and initial physical and dynamical characterization of the object 2003 UB313. The object is sufficiently bright that for all reasonable values of the albedo it is certain to be larger than Pluto. Pre-discovery observations back to 1989 are used to obtain an orbit with extremely small errors. The object is currently at aphelion in wha

W. P. Chen, Kaushar Sanchawala, M. C. Chiou

We present cross-identification of archived X-ray point sources with W UMa variable stars found in the All-Sky Automated Survey (ASAS). In a surveyed sky area of 300 square degrees of ASAS, 36 W UMa stars have been found associated with X-ray emission. We compute the distances of these W UMa systems and hence their X-ray luminosities. Our data support the &#

E. Di Grezia, S. Esposito, G. Salesi

We analyze the phenomenological consequences of a Lorentz violating energy-momentum dispersion relation in order to give a simple explanation for the baryon asymmetry in the Universe. By assuming very few hypotheses, we propose a straightforward mechanism for generating the observed matter-antimatter asymmetry which entails a Lorentz-breakdown energy scale o

D. E. Lopez-Fogliani, C. Munoz

The fact that neutrinos are massive suggests that the minimal supersymmetric standard model (MSSM) might be extended in order to include three gauge-singlet neutrino superfields with Yukawa couplings of the type $H_2 L ν^c$. We propose to use these superfields to solve the $μ$ problem of the MSSM without having to introduce an extra singlet superfield as in

Mark S. Byrd

The use of d-state systems, or qudits, in quantum information processing is discussed. Three-state and higher dimensional quantum systems are known to have very different properties from two-state systems, i.e., qubits. In particular there exist qudit states which are not equivalent under local unitary transformations unless a selection rule is violated. Thi

Charles A. Rohde, Keisuke Hasegawa, Miriam Deutsch

We report on measurements of visible extinction spectra of semicontinuous silver nanoshells grown on colloidal silica spheres. We find that thin, fractal shells below the percolation threshold exhibit geometrically tunable plasmon resonances. A modified scaling theory approach is used to model the dielectric response of such shells, which is then utilized to

B Sriram Shastry

We display an interesting sum rule for the dynamical thermal conductivity for many standard models of condensed matter in terms of the expectation of a thermal operator. We present the thermal operator for several model systems of current interest, which enable an evaluation of the sum rule and the Lorentz number, the thermo electric figure of merit as well

Aleksandar Bogojevic, Antun Balaz, Aleksandar Belic

A recently developed analytical method for systematic improvement of the convergence of path integrals is used to derive a generalization of Euler&#39;s summation formula for path integrals. The first $p$ terms in this formula improve convergence of path integrals to the continuum limit from 1/N to $1/N^p$, where $N$ is the coarseness of the discretization.

Per Kraus, Finn Larsen

In the AdS/CFT correspondence one encounters theories that are not invariant under diffeomorphisms. In the boundary theory this is a gravitational anomaly, and can arise in 4k+2 dimensions. In the bulk, there can be gravitational Chern-Simons terms which vary by a total derivative. We work out the holographic stress tensor for such theories, and demonstrate

P. Di Francesco, P. Zinn-Justin

We prove higher rank analogues of the Razumov--Stroganov sum rule for the groundstate of the O(1) loop model on a semi-infinite cylinder: we show that a weighted sum of components of the groundstate of the A_{k-1} IRF model yields integers that generalize the numbers of alternating sign matrices. This is done by constructing minimal polynomial solutions of t

W. A. Christiansen, Y. Jack Ng, H. van Dam

Due to quantum fluctuations, spacetime is probably ``foamy&#39;&#39; on very small scales. We propose to detect this texture of spacetime foam by looking for core-halo structures in the images of distant quasars. We find that the Very Large Telescope interferometer will be on the verge of being able to probe the fabric of spacetime when it reaches its design

C. M. Ho, D. Boyanovsky, H. J. de Vega

Neutrino oscillations in the early Universe prior to the epoch of primordial nucleosynthesis is studied by implementing real time non-equilibrium field theory methods. We focus on two flavors of Dirac neutrinos, however, the formulation is general. We obtain the equations of motion for neutrino wavepackets of either chirality and helicity in the plasma allow

A. V. Bratchikov

This paper has been withdrawn by the author.The formula which was proposed gives only a second order deformation.

Yuval Peres, Oded Schramm, Scott Sheffield, David B. Wilson

The game of Hex has two players who take turns placing stones of their respective colors on the hexagons of a rhombus-shaped hexagonal grid. Black wins by completing a crossing between two opposite edges, while White wins by completing a crossing between the other pair of opposite edges. Although ordinary Hex is famously difficult to analyze, Random-Turn Hex

Catherine Mia Ihm, Vassiliki Kalogera, Krzysztof Belczynski

Recent pulsar surveys have increased the number of observed double neutron stars (DNS) in our galaxy enough so that observable trends in their properties are starting to emerge. In particular, it has been noted that the majority of DNS have eccentricities less than 0.3, which are surprisingly low for binaries that survive a supernova explosion that we believ

G. Vernizzi, P. Ribeca, H. Orland, A. Zee

We consider the folding of a self-avoiding homopolymer on a lattice, with saturating hydrogen bond interactions. Our goal is to numerically evaluate the statistical distribution of the topological genus of pseudoknotted configurations. The genus has been recently proposed for classifying pseudoknots (and their topological complexity) in the context of RNA fo

Daniel M. Gordon

Delsarte conjectured in 1973 that there are no nontrivial pefect codes in the Johnson scheme. Etzion and Schwartz recently showed that perfect codes must be k-regular for large k, and used this to show that there are no perfect codes correcting single errors in J(n,w) for n <= 50000. In this paper we show that there are no perfect single error-correcting cod

Yu Lu, H. J. Mo, Neal Katz, Martin D. Weinberg

N-body simulations predict that CDM halo-assembly occurs in two phases: 1) a fast accretion phase with a rapidly deepening potential well; and 2) a slow accretion phase characterised by a gentle addition of mass to the outer halo with little change in the inner potential well. We demonstrate, using one-dimensional simulations, that this two-phase accretion l

Dmitri Piontkovski, Sergei Silvestrov

We develop the cohomology theory of color Lie superalgebras due to Scheunert--Zhang in a framework of nonhomogeneous quadratic Koszul algebras. In this approach, the Chevalley--Eilenberg complex of a color Lie algebra becomes a standard Koszul complex for its universal enveloping algebra. As an application, we calculate cohomologies with trivial coefficients

Henric Krawczynski

Imaging Atmospheric Cherenkov Telescopes (IACTs) allow us to observe Active Galactic Nuclei (AGNs) in the 100 GeV to 20 TeV energy range with high sensitivity. The TeV gamma-ray observations of the nine blazars detected so far in this energy range reveal rapid flux and spectral variability on time scales of several hours, sometimes even on time scales of a f

Andrew Raich

Let $p:\mathbb{C}\to\mathbb{R}$ be a subharmonic, nonharmonic polynomial and $τ$ a real parameter. Define $\bar{Z}_{τp} = \partial_{\bar z} + τp_{\bar z}$, a closed, densely-defined operator on $L^2(\mathbb{C})$. If $\Box_{τp} = \bar{Z}_{τp}\bar{Z}_{τp}^*$ and $τ>0$, we solve the heat equation $ (\partial_s + \Box_{τp}) u =0$, $u(0,z) = f(z)$, on $(0,\infty)

Paul Benioff

A quantum theoretic representation of real and complex numbers is described here as equivalence classes of Cauchy sequences of quantum states of finite strings of qubits. There are 4 types of qubits each with associated single qubit annihilation creation (a-c) operators that give the state and location of each qubit type on a 2 dimensional integer lattice. T

Yuan Liang Lim, Sean D. Barrett, Almut Beige, Pieter Kok

We introduce an architecture for robust and scalable quantum computation using both stationary qubits (e.g. single photon sources made out of trapped atoms, molecules, ions, quantum dots, or defect centers in solids) and flying qubits (e.g. photons). Our scheme solves some of the most pressing problems in existing non-hybrid proposals, which include the diff

Claus Kiefer

I briefly review the current status of quantum gravity. After giving some general motivations for the need of such a theory, I discuss the main approaches in quantizing general relativity: Covariant approaches (perturbation theory, effective theory, and path integrals) and canonical approaches (quantum geometrodynamics, loop quantum gravity). I then address

Alan M. Kadin

Low-temperature electronic systems require electrical leads which have low electrical resistance to provide bias current I without excessive voltage drop V. But proper cryogenic design also requires high thermal resistance to maintain a minimum heat leak Q from the hot temperature T[hot] to the cold temperature T[cold]. By the Wiedemann-Franz law, these requ

Pavel A. Belov, Yang Hao, Sunil Sudhakaran

Original realization of a lens capable to transmit images with sub-wavelength resolution is proposed. The lens is formed by parallel conducting wires and effectively operates as a telegraph: it captures image at the front interface and the transmit it to the back interface without distortion. This regime of operation is called canalization and is inherent in

Matthias Kuenzer

Let E be a Frobenius category, let_E_ denote its stable category. The shift functor on_E_ induces a first shift functor on the category of acyclic complexes with entries in_E_ by pointwise application. Shifting a complex by 3 positions yields a second shift functor on this category. Passing to the quotient modulo split acyclic complexes, Heller remarked that

J. E. Avron, B. Gutkin, D. H. Oaknin

We propose a quantum theory of swimming for swimmers that are small relative to the coherence length of the medium. The quantum swimming equation is derived from known results on quantum pumps. For a one-dimensional Fermi gas at zero temperature we find that swimming is topological: The distance covered in one swimming stroke is quantized in half integer mul

H. Watanabe, S. Yukawa, M. A. Novotny, N. Ito

We construct asymptotic arguments for the relative efficiency of rejection-free Monte Carlo (MC) methods compared to the standard MC method. We find that the efficiency is proportional to $\exp{({const} β)}$ in the Ising, $\sqrtβ$ in the classical XY, and $β$ in the classical Heisenberg spin systems with inverse temperature $β$, regardless of the dimension.

C. Quesne

The problem of d-dimensional Schrodinger equations with a position-dependent mass is analyzed in the framework of first-order intertwining operators. With the pair (H, H_1) of intertwined Hamiltonians one can associate another pair of second-order partial differential operators (R, R_1), related to the same intertwining operator and such that H (resp. H_1) c

Dimitrios Tsimpis

We perform a systematic search for all possible massive deformations of IIA supergravity in ten dimensions. We show that there exist exactly two possibilities: Romans supergravity and Howe-Lambert-West supergravity. Along the way we give the full details of the ten-dimensional superspace formulation of the latter. The scalar superfield at canonical mass dime

D. V. Denisov, A. L. Rakhmanov, D. V. Shantsev, Y. M. Galperin

Recent theoretical analysis of spatially-nonuniform modes of the thermomagnetic instability in superconductors [Phys. Rev. B 70, 224502 (2004)] is generalized to the case of a thin film in a perpendicular applied field. We solve the thermal diffusion and Maxwell equations taking into account nonlocal electrodynamics in the film and its thermal coupling to th

Biswarup Mukhopadhyaya, Santosh Kumar Rai

Doubly charged scalars, predicted in many models having exotic Higgs representations, can in general have lepton-number violating (LFV) couplings. The basis of most searches for this charged scalar has been to look for its direct production and its subsequent decay to like-sign final state leptons. In this work we show that by using an associated monoenerget

Sébastien Peirani, José Antonio De Freitas Pacheco

The spherical infall model first developed by Lemaître and Tolman was modified in order to include the effects of a dark energy term. The resulting velocity-distance relation was evaluated numerically. This equation, when fitted to actual data, permits the simultaneous evaluation of the central mass and of the Hubble parameter. Application of this relation t

Nikolai Kochelev, Dong-Pil Min

We consider the parity doublet structure observed in high hadronic excitations within the instanton model for the QCD vacuum. In the conventional approach this doubling phenomenon is treated as a manifestation of the partial restoration of chiral or $U(1)_A$ symmetry. We demonstrate that the suppression of direct instanton contribution to the masses of excit

Troels Harmark, Poul Olesen

We study the structure of stationary and axisymmetric metrics solving the vacuum Einstein equations of General Relativity in four and higher dimensions, building on recent work in hep-th/0408141. We write the Einstein equations in a new form that naturally identifies the sources for such metrics. The sources live in a one-dimensional subspace and the entire

P. -M. Billangeon, F. Pierre, H. Bouchiat, R. Deblock

We measure current fluctuations of mesoscopic devices in the quantum regime, when the frequency is of the order of or higher than the applied voltage or temperature. Detection is designed to probe separately the absorption and emission contributions of current fluctuations, i.e. the positive and negative frequencies of the Fourier transformed nonsymmetrized

Gizem Karaali

We review recent results in the study of quantum groups in the super setting. In particular, we provide an overview of results about solutions of the Yang-Baxter equations in the super setting and begin to develop the super analog of the theory of dynamical quantum groups.

A. Yu. Khrennikov, S. V. Kozyrev

Free evolution for quantum particle in general ultrametric space is considered. We find that if mean zero wave packet is localized in some ball in the ultrametric space then its evolution remains localized in the same ball.

Matthew J. Davis, P. Blair Blakie

The ergodic hypothesis asserts that a classical mechanical system will in time visit every available configuration in phase space. Thus, for an ergodic system, an ensemble average of a thermodynamic quantity can equally well be calculated by a time average over a sufficiently long period of dynamical evolution. In this paper we describe in detail how to calc

Tatsuo Kobayashi, Carlos Munoz

In realistic four-dimensional string constructions the presence of anomalous U(1)&#39;s is generic. In addition, the associated Fayet-Iliopoulos contribution to the D-term can break the extra gauge symmetries. As a consequence, physical particles can appear combined with other states. We show that even if a three-generation standard-like model has originally

Osamu Fujino

We reformulate base point free theorems. Our formulation is flexible and has some important applications. One of the main purposes of this paper is to prove a generalization of the base point free theorem in Fukuda&#39;s paper: On numerically effective log canonical divisors.

Tonatiuh Matos, Dario Nunez

We derive an exact solution to the Einstein&#39;s equations with a stress-energy tensor corresponding to an opposite-sign scalar field, and show that such a solution describes the internal region of a rotating wormhole. We also derive an static wormhole asymptotically flat solution and match them on both regions, thus obtaining an analytic solution for the c

Stuart Wyithe, Abraham Loeb

Following the completion of cosmic reionization, the mean-free-path of ionizing photons was set by a population of Ly-limit absorbers. As the mean-free-path steadily grew, the intensity of the ionizing background also grew, thus lowering the residual neutral fraction of hydrogen in ionization equilibrium throughout the diffuse intergalactic medium (IGM). Ly-