May 2003 arXiv papers — page 11

G. Russo, L. M. Sander, P. Smereka

We introduce an algorithm for treating growth on surfaces which combines important features of continuum methods (such as the level-set method) and Kinetic Monte Carlo (KMC) simulations. We treat the motion of adatoms in continuum theory, but attach them to islands one atom at a time. The technique is borrowed from the Dielectric Breakdown Model. Our method

J. Henk, P. Bruno

Motivated by first-principles results for jellium and by surface-barrier shapes that are typically used in electron spectroscopies, the bias voltage in ballistic vacuum tunneling is treated in a heuristic manner. The presented approach leads in particular to a parameterization of the tunnel-barrier shape, while retaining a first-principles description of the

S. A. Morgan, M. Rusch, D. A. W. Hutchinson, K. Burnett

We present numerical results from a full second order quantum field theory of Bose-Einstein condensates applied to the 1997 JILA experiment [D. S. Jin et al., Phys. Rev. Lett. Vol. 78, 764 (1997)]. Good agreement is found for the energies and decay rates for both the lowest-energy m = 2 and m = 0 modes. The anomalous behaviour of the m = 0 mode is due to exp

N. Shah, A. J. Millis

We study theoretically the dynamics of an ``xxz'' spin necklace coupled to a conduction electron sea, a model system for a nanostructure in a dissipative environment. We extract the long-time behavior via a mapping to a multichannel Coulomb gas problem followed by a scaling analysis. The strong quantum fluctuations of the necklace cause a nontrivial

B. Rotenberg, J. Dzubiella, J. -P. Hansen, A. A. Louis

We use thermodynamic perturbation theory to calculate the free energies and resulting phase diagrams of binary systems of spherical colloidal particles and interacting polymer coils in good solvent within an effective one-component representation of such mixtures, whereby the colloidal particles interact via a polymer-induced depletion potential. MC simulati

R. Fantoni, G. Pastore

A recently proposed connection between the threshold for the stability of the iterative solution of integral equations for the pair correlation functions of a classical fluid and the structural instability of the corresponding real fluid is carefully analyzed. Direct calculation of the Lyapunov exponent of the standard iterative solution of HNC and PY integr

J. Henk, A. Ernst, P. Bruno

The electron spin polarization (ESP) of the L-gap surface states on Au(111) is investigated theoretically by means of first-principles electronic-structure and photoemission calculations. The surface states show a large spin-orbit induced in-plane ESP which is perpendicular to the in-plane wavevector, in close analogy to a two-dimensional electron gas with R

Ryuji Higashinaka, Hideto Fukazawa, Yoshiteru Maeno

We report the specific heat and entropy of single crystals of the spin ice compound Dy2Ti2O7 at temperatures down to 0.35 K. We apply magnetic fields along the four characteristic directions: [100], [110], [111] and [112]. Because of Ising anisotropy, we observe anisotropic release of the residual zero-point entropy, attributable to the difference in frustra

Fredrik Liljeros, Christofer R. Edling, H. Eugene Stanley, Y. Aberg

In a recent paper, James Holland Jones and Mark Handcock re-analyze two of the four datasets comprising a database, first analyzed by us, which records the number of distinct sexual partners for Swedish men and women. We argue that the claims of Jones and Handcock can be interpreted in a misleading fashion.

K. Kakuyanagi, K. Kumagai, Y. Matsuda, M. Hasegawa

Spatially-resolved NMR is used to probe the magnetism in and around vortex cores of nearly optimally-doped Tl_2Ba_2CuO_{6+x} (Tc=85 K). The NMR relaxation rate 1/T_1 at Tl site provides a direct evidence that the AF spin correlation is significantly enhanced in the vortex core region. In the core region Cu spins show a local AF ordering with moments parallel

Georgios M. Nikolopoulos, P. Lambropoulos, N. P. Proukakis

We present a computational approach to the outcoupling in a simple one-dimensional atom laser model, the objective being to circumvent mathematical difficulties arising from the breakdown of the Born and Markov approximations. The approach relies on the discretization of the continuum representing the reservoir of output modes, which allows the treatment of

C. Senatore, M. Polichetti, N. Clayton, R. Flukiger

In a type-II superconductor the generation of higher harmonics in the magnetic response to an alternating magnetic field is a consequence of the non-linearity in the I-V relationship. The shape of the current-voltage (I-V) curve is determined by the current dependence of the thermal activation energy U(J) and is thus related to the dynamical regimes governin

Kavita Joshi, D. G. Kanhere

We have carried out extensive isokinetic {\it ab initio} molecular dynamic simulations to investigate the finite temperature properties of the impurity doped cluster Li$_6$Sn along with the host cluster Li$_7$. The data obtained from about 20 temperatures and total simulation time of at least 3 ns is used to extract thermodynamical quantities like canonical

Anders Levermann, Itamar Procaccia

We report a new algorithm to generate Laplacian Growth Patterns using iterated conformal maps. The difficulty of growing a complete layer with local width proportional to the gradient of the Laplacian field is overcome. The resulting growth patterns are compared to those obtained by the best algorithms of direct numerical solutions. The fractal dimension of

A. Yu. Aladyshkin, A. I. Buzdin, A. A. Fraerman, A. S. Mel'nikov

On the basis of phenomenological Ginzburg-Landau approach we investigate the problem of order parameter nucleation in hybrid superconductor/ferromagnetic systems with a domain structure in applied external magnetic field. Both the isolated domain boundaries and periodic domain structures in ferromagnetic layers are considered. We study the interplay between

Seiji Miyoshi, Masato Okada

It is known that storage capacity per synapse increases by synaptic pruning in the case of a correlation-type associative memory model. However, the storage capacity of the entire network then decreases. To overcome this difficulty, we propose decreasing the connecting rate while keeping the total number of synapses constant by introducing delayed synapses.

Igor F. Herbut, Dominic J. Lee

We study the spin dynamics in underdoped cuprates at low temperatures by considering them as quasi two dimensional d-wave superconductors (dSC) with strong phase fluctuations. An effective theory of spin degrees of freedom of nodal quasiparticles coupled to vortex defects in the phase of the superconducting order parameter is formulated. It represents the mi

Yukitoshi Motome, Nobuo Furukawa

Spin excitation spectrum is studied in the double exchange model in the presence of disorder. Spin wave approximation is applied in the lowest order of 1/S expansion. The disorder causes anomalies in the spin excitation spectrum such as broadening, branching, anticrossing with gap opening. The origin of the anomalies is the Friedel oscillation, in which the

Andrew Das Arulsamy

Comment on "Fe valency-induced effect on the magnetic and electrotransport properties in Nd$_{0.67}$Sr$_{0.33}$Mn$_{1-x}$Fe$_x$O$_3$ polycrystalline system" [Appl. Phys. Lett. 82, 1721 (2003)]

Anatoli Polkovnikov

We consider dynamics of boson condensates in finite optical lattices under a slow external perturbation which brings the system to the unstable equilibrium. It is shown that quantum fluctuations drive the condensate into the maximally entangled state. We argue that the truncated Wigner approximation being a natural generalization of the Gross-Pitaevskii clas

Francois Coppex, Michel Droz, Jaroslaw Piasecki, Emmanuel Trizac

We consider the velocity distribution for a granular gas of inelastic hard spheres described by the Boltzmann equation. We investigate both the free of forcing case and a system heated by a stochastic force. We propose a new method to compute the first correction to Gaussian behavior in a Sonine polynomial expansion quantified by the fourth cumulant $a_2$. O

C. O. Heinke, J. E. Grindlay, P. M. Lugger, H. N. Cohn

Quiescent low-mass X-ray binaries (qLMXBs) containing neutron stars have been identified in several globular clusters using Chandra or XMM X-ray observations, using their soft thermal spectra. We report a complete census of the qLMXB population in these clusters, identifying three additional probable qLMXBs in NGC 6440. We conduct several analyses of the qLM

C. Borys, S. C. Chapman, M. Halpern, D. Scott

We investigate the emission of sub-millimetre-wave radiation from galaxies in a 165 square arcminute region surrounding the Hubble Deep Field North. The data were obtained from dedicated observing runs from our group and others using the SCUBA camera on the James Clerk Maxwell Telescope, and combined using techniques specifically developed for low signal-to-

C. O. Heinke, J. E. Grindlay, P. D. Edmonds, D. A. Lloyd

We report our analysis of a Chandra X-ray observation of the rich globular cluster M80, in which we detect some 19 sources to a limiting 0.5-2.5 keV X-ray luminosity of 7*10^30 ergs/s within the half-mass radius. X-ray spectra indicate that two of these sources are quiescent low-mass X-ray binaries (qLMXBs) containing neutron stars. We identify five sources

C. Travaglio, K. Kifonidis, E. Mueller

We investigate explosive nuclear burning in core collapse supernovae by coupling a tracer particle method to one and two-dimensional Eulerian hydrodynamic calculations. Adopting the most recent experimental and theoretical nuclear data, we compute the nucleosynthetic yields for 15 Msun stars with solar metallicity, by post-processing the temperature and dens

Tanmay Vachaspati

Eternal inflation is shown to require violations of the Null Energy Condition (NEC) on superhorizon scales. With light scalar fields as the matter sources in a de Sitter background, there can be no classical or semiclassical violations of the NEC. However, quantum fluctuations of the energy-momentum tensor, described by an expectation value of four field ope

William G. Mathews, Fabrizio Brighenti

We propose a stellar origin for the central dust clouds observed in most giant elliptical galaxies. Dusty gas ejected from evolving red giant stars in E or cD galaxies can cool rapidly even after entering the hot, X-ray emitting gas. Cooling by thermal collisions with dust grains can be faster than either the dynamical time in the galactic potential or the g

R. C. Kennicutt,, L. Armus, G. Bendo, D. Calzetti

The SIRTF Nearby Galaxy Survey is a comprehensive infrared imaging and spectroscopic survey of 75 nearby galaxies. Its primary goal is to characterize the infrared emission of galaxies and their principal infrared-emitting components, across a broad range of galaxy properties and star formation environments. SINGS will provide new insights into the physical

S. Saar, S. Seager

We point out some advantages of making observations of extrasolar planets in linearly polarized (LP) light. Older cool stars have quite low levels (~ 10^-4 to 10^-5) of fractional LP, while extrasolar planets can have relatively high fractional LP (~0.1). Observations in LP light can therefore significantly enhance contrast between the planet and its parent

G. G. Pavlov, V. E. Zavlin

Observations of thermal radiation from neutron stars allow one to measure the surface temperatures and confront them with cooling scenarios. Detection of gravitationally redshifted spectral lines can yield the mass-to-radius ratio. In the few cases when the distance is known, one can measure the neutron star radius, which is particularly important to constra

N. C. Santos, S. Udry, M. Mayor, D. Naef

The presence of a planet around the K dwarf HD192263 was recently called into question by the detection of a periodic photometric signal with the same period as the one observed in radial velocity. In this paper, we investigate this possibility, using a combination of radial-velocity, photometry, and bisector measurements obtained simultaneously. The results

A. Bershadskii

Scaling properties of the cosmic microwave background (CMB) radiation are studied using satellite (COBE-DMR maps), balloon-borne and ground-based (combined QMASK map) data. Quantitative consistency is found between the multiscaling properties of the COBE-DMR and QMASK CMB maps. Surprisingly, it is found that the observed CMB temperature multiscaling resemble

M. Rejkuba, D. Minniti, D. R. Silva

The first variable star catalogue in a giant elliptical galaxy NGC 5128 (Centaurus A) is presented. Using multi-epoch observations with ISAAC at the VLT we have detected 1504 red variables in two halo fields covering 10.46 arcmin square. For the variables with at least 10 good measurements, periods and amplitudes were determined using Fourier analysis and no

M. Pedani

In the last three decades, the Ultra Steep spectrum tecnique has been exploited by many groups since it was demonstrated that radio sources with very steep spectra (Alpha < -1.0) are good tracers of high-z radio galaxies (HzRGs; z>2). Though more than 150 HzRGs have been discovered up to now with this tecnique, little is known about its real effectiveness, a

W. Bednarek

In the recent paper we calculated the $γ$-ray spectra from pulsar wind nebulae (PWNe), assuming that a significant amount of the pulsar rotational energy is converted into relativistic nuclei. These nuclei accelerate leptons which are responsible for most of the observed electromagnetic emission from PWNe. Small part of nuclei also interact with the matter o

Hans-Joachim Drescher, Glennys Farrar, Marcus Bleicher, Manuel Reiter

The SENECA model, a new hybrid approach to air shower simulations, is presented. It combines the use of efficient cascade equations in the energy range where a shower can be treated as one-dimensional, with a traditional Monte Carlo method which traces individual particles. This allows one to reproduce natural fluctuations of individual showers as well as th

M. Douspis, J. G. Bartlett, A. Blanchard

Application of a Goodness--of--fit (GOF) statistic is an essential element of parameter estimation. We discuss the computation of GOF when estimating parameters from anisotropy measurements of the cosmic microwave background (CMB), and we propose two GOF statistics to be used when employing approximate band--power likelihood functions. They are based on an a

R. Buta, D. L. Block, J. H. Knapen

We describe a Fourier-based method of separating bars from spirals in near-infrared images. The method takes advantage of the fact that a bar is typically a feature with a relatively fixed position angle, and uses the simple assumption that the relative Fourier amplitudes due to the bar decline with radius past a maximum in the same or a similar manner as th

Z. G. Dai, X. F. Wu

We present an explanation for the unusual temporal feature of the GRB 030226 afterglow. The R-band afterglow of this burst faded as ~ t^{-1.2} in ~ 0.2 days after the burst, rebrightened during the period of ~ 0.2 - 0.5 days, and then declined with ~ t^{-2.0}. To fit such a light curve, we consider an ultrarelativistic jetted blast wave expanding in a densit

J. S. Kaastra, R. Lieu, T. Tamura, F. B. S. Paerels

XMM-Newton recently discovered O VII line emission from ~2 million K gas near the outer parts of several clusters of galaxies. This emission is attributed to the Warm-Hot Intergalactic Medium. The original sample of clusters studied for this purpose has been extended and two more clusters with a soft X-ray excess have been found. We discuss the physical prop

R. Genzel, R. Schoedel, T. Ott, F. Eisenhauer

We analyze deep near-IR adaptive optics imaging as well as new proper motion data of the nuclear star cluster of the Milky Way. The surface density distribution of faint stars peaks within 0.2&#34; of the black hole candidate SgrA*. The radial density distribution of this stellar &#39;cusp&#39; follows a power law of exponent 1.3-1.4. The K-band luminosity f

Noam Soker, Oded Regev

We reexamine a previously proposed model for thermal pressure acceleration of collimated outflows in young stellar objects (YSO). We are motivated by new results from recent X-ray observations of YSO. These show that there is essentially no difference between the properties of X-ray emission from YSO with and without outflows, imposing quite severe constrain

Rosalba Perna, Ramesh Narayan, George Rybicki, Luigi Stella

A large number of neutron stars (NSs), ~10^9, populate the Galaxy, but only a tiny fraction of them is observable during the short radio pulsar lifetime. The majority of these isolated NSs, too cold to be detectable by their own thermal emission, should be visible in X-rays as a result of accretion from the interstellar medium. The ROSAT all sky survey has h

M. Opher, P. C. Liewer, T. I. Gombosi, W. Manchester

The Voyager spacecraft is now approaching the edge of the solar system. Near the boundary between the solar system and the interstellar medium we find that an unstable ``jet-sheet&#39;&#39; forms. The jet-sheet oscillates up and down due to a velocity shear instability. This result is due to a novel application of a state-of-art 3D Magnetohydrodynamic (MHD)

M. Tosi

Studies of the resolved stellar populations in nearby systems are crucial to understand galaxy evolution. Here, we summarize how the interpretation of the colour-magnitude diagrams of field stars in late-type dwarfs inside and outside the Local Group has allowed us to infer their star formation histories and put useful constraints on the evolution of this ty

E. Waxman

The origin of energetic gamma-ray bursts is still unknown. But the detection of polarization of gamma-rays provides fresh insight into the mechanism driving these powerful explosions.

R. J. West, S. Nazarenko, J. P. Laval, S. Galtier

We present the results of a numerical investigation of the turbulent kinematic dynamo problem in a high Prandtl number regime. The scales of the magnetic turbulence we consider are far smaller than the Kolmogorov dissipative scale, so that the magnetic wavepackets evolve in a nearly smooth velocity field. Firstly, we consider the Kraichnan-Kazantsev model (K

B. E. J. Pagel

Highlights of the meeting include new insights into r and s-processes and an explosion of interesting abundance data on stars in the Galactic halo and in dwarf spheroidal galaxies. I include in this summary a few suggestions on the chemical evolution of the Thick and Thin disks, and on the present and past distribution of baryons and metals in the universe.

Yong-Seon Song, Lloyd Knox

We study the detectability, given CMB polarization maps, of departures from the inflationary consistency equation, r \equiv T/S \simeq -5 n_T, where T and S are the tensor and scalar contributions to the quadrupole variance, respectively. The consistency equation holds if inflation is driven by a slowly-rolling scalar field. Departures can be caused by: 1) h

Kentaro Nagamine, Volker Springel, Lars Hernquist

We study the distribution of the star formation rate and metallicity of damped Lyman-alpha absorbers using cosmological SPH simulations of the Lambda cold dark matter model in the redshift range z=0-4.5. Our approach includes a phenomenological model of galactic wind. We find that there is a positive correlation between the projected stellar mass density and

Andreas Karch

We point out that gravity on dS_n gives rise to a localized graviton on dS_{n-1}. This way one can derive a recursion relation for the entropy of dS spaces, which might have interesting implications for dS holography. In the same spirit we study domain walls interpolating between dS spaces with different cosmological constant. Our observation gives an easy w

Julián Manzano, Jörgen Blomvall

In this article we present a non-linear dynamic programming algorithm for the computation of forward rates within the maximum smoothness framework. The algorithm implements the forward rate positivity constraint for a one-parametric family of smoothness measures and it handles price spreads in the constraining dataset. We investigate the outcome of the algor

H. Hansen, G. Chanfray

We present some applications of the renormalized RPA in bosonic field theories. We first present some developments for the explicit calculation of the total energy in Phi^4 theory and discuss its phase structure in 1+1 dimensions. We also demonstrate that the Goldstone theorem is satisfied in the O(N) model within the renormalized RPA.

Jonathan Granot, Abraham Loeb

We calculate the time evolution of the flux, apparent size, and image centroid motion of gamma-ray burst (GRB) radio jets, and show that they can be resolved by the VLBA at distances of hundreds of Mpc. We find that GRB 030329 which showed spectroscopic evidence for an associated Type Ic supernova (SN) at a distance of $\approx$ 800 Mpc might just be resolva

H. A. Alhendi, E. I. Lashin

We use a power-series expansion to calculate the eigenvalues of anharmonic oscillators bounded by two infinite walls. We show that for large finite values of the separation of the walls, the calculated eigenvalues are of the same high accuracy as the values recently obtained for the unbounded case by the inner-product quantization method. We also apply our m

M. B. Hastings

A generalization of the Lieb-Schultz-Mattis theorem to higher dimensional spin systems is shown. The physical motivation for the result is that such spin systems typically either have long-range order, in which case there are gapless modes, or have only short-range correlations, in which case there are topological excitations. The result uses a set of loop o

Abhay Ashtekar, Alejandro Corichi

The black hole entropy calculation for type I isolated horizons, based on loop quantum gravity, is extended to include non-minimally coupled scalar fields. Although the non-minimal coupling significantly modifies quantum geometry, the highly non-trivial consistency checks for the emergence of a coherent description of the quantum horizon continue to be met.

Y. Bergner, Luis M. A. Bettencourt

Many quantum field theoretical models possess non-trivial solutions which are stable for topological reasons. We construct a self-consistent example for a self-interacting scalar field--the quantum (or dressed) kink--using a two particle irreducible effective action in the Hartree approximation. This new solution includes quantum fluctuations determined self

Magdalena Djordjevic, Miklos Gyulassy

The color dielectric modification of the gluon dispersion relation in a dense QCD medium suppresses both the soft and collinear gluon radiation associated with jet production. We compute both the longitudinal and transverse plasmon contributions to the zeroth order in opacity radiative energy loss. This QCD analog of the Ter-Mikayelian effect in QED leads to

Jeppe R. Andersen, Agustin Sabio Vera

The Balitsky-Fadin-Kuraev-Lipatov equation in the next-to-leading logarithmic approximation is solved using an iterative method. We derive the solution for forward scattering with all conformal spins. A discussion of the infrared finiteness of the results is included.

Guanghan Cao, Chunmu Feng, Yi Xu, Wen Lu

We report the electrical, magnetic and thermal measurements on a layered cobalt oxyhydrate Na$_{0.31}$CoO$_{2}\cdot$1.3H$_{2}$O. Bulk superconductivity at 4.3 K has been confirmed, however, the measured superconducting fraction is relatively low probably due to the sample&#39;s intrinsic two-dimensional characteristic. The compound exhibits weak-coupled and

L. Coraggio, N. Itaco, A. Covello, A. Gargano

Ground-state properties of 16O and 40Ca are calculated with a low-momentum nucleon-nucleon potential, V-low-k, derived from the chiral N3LO interaction recently constructed by Entem and Machleidt. The smooth V-low-k is used directly in a Hartree-Fock approach, avoiding the difficulties of the Brueckner-Hartree-Fock procedure. Corrections up to third order in

Yves Demasure, Romuald A. Janik

We compute the decay of an unstable D9 brane in type IIA string theory including backreaction effects using an effective field theory approach. The open string tachyon on the brane is coupled consistently to the space-time metric, the dilaton and the RR 9-form. The purpose of this note is to address the fate of the open string energy density, which remains c

Oleg I. Lobkis, Igor S. Rozhkov, Richard L. Weaver

We study the dissipation of diffuse ultrasonic energy in a reverberant body coupled to a waveguide, an analog for a mesoscopic electron in a quantum dot. A simple model predicts a Porter-Thomas like distribution of level widths and corresponding nonexponential dissipation, a behavior largely confirmed by measurements. For the case of fully open channels, how

N. Mukunda, S. Chaturvedi, R. Simon

Wigner distributions for quantum mechanical systems whose configuration space is a finite group of odd order are defined so that they correctly reproduce the marginals and have desirable transformation properties under left and right translations. While for the Abelian case we recover known results, though from a different perspective, for the non Abelian ca

Christine Meurer

First results on the production of Xi and AntiXi hyperons in Pb+Pb interactions at 40 AGeV are presented. The AntiXi/Xi ratio at midrapidity is studied as a function of collision centrality. The ratio shows no significant centrality dependence within statistical errors; it ranges from 0.07 to 0.15. The AntiXi/Xi ratio for central Pb+Pb collisions increases s

R. Hofmann, F. Paccetti Correia, M. G. Schmidt, Z. Tavartkiladze

We present possible realizations of gauge inflation arising from a 5D ${\cal N}=1$ supersymmetric U(1) model, where the extra dimension is compactified on a circle. A one-loop inflaton effective 4D potential is generated, with the inflaton being a &#39;Wilson-line field&#39;. It relies on a SUSY breaking. We first consider SUSY breaking to occur spontaneousl

Mayeul Arminjon

A new method of post-Newtonian approximation (PNA) for weak gravitational fields is presented together with its application to test an alternative, scalar theory of gravitation. The new method consists in defining a one-parameter family of systems, by applying a Newtonian similarity transformation to the initial data that defines the system of interest. This

H. Mäkelä, Y. Zhang, K. -A. Suominen

We investigate the structure of topological defects in the ground states of spinor Bose-Einstein condensates with spin F=1 or F=2. The type and number of defects are determined by calculating the first and second homotopy groups of the order-parameter space. The order-parameter space is identified with a set of degenerate ground state spinors. Because the st

L. Metcalfe, J. -P. Kneib, B. McBreen, B. Altieri

ISOCAM was used to perform a deep survey through three gravitationally lensing clusters of galaxies. Nearly seventy sq. arcmin were covered over the clusters A370, A2218 and A2390. We present maps and photometry at 6.7 & 14.3 microns, showing a total of 145 mid-IR sources and the associated source counts. The 15 micron counts reach the faintest level yet rec

Lubomir Gavrilov, Iliya D. Iliev

We study the displacement map associated to small one-parameter polynomial unfoldings of polynomial Hamiltonian vector fields on the plane. Its leading term, the generating function $M(t)$, has an analytic continuation in the complex plane and the real zeroes of $M(t)$ correspond to the limit cycles bifurcating from the periodic orbits of the Hamiltonian flo

Ue-Li Pen

I present a weak lensing sensitivity estimate for upcoming high redshift (epoch of reionization and beyond) 21cm surveys. Instruments such as PAST, LOFAR and SKA should be able to measure the weak lensing power spectrum to precisions far exceeding conceivable optical surveys. Three types of sources are detectable, which include the re-ionization stromgren sp

R. Kretschmer, L. Szymanowski

In infinite-dimensional Hilbert spaces, the application of the concept of quasi-Hermiticity to the description of non-Hermitian Hamiltonians with real spectra may lead to problems related to the definition of the metric operator. We discuss these problems by examining some examples taken from the recent literature and propose a formulation that is free of th

Vyacheslav S. Rychkov

We propose a &#34;Copenhagen interpretation&#34; for spacetime noncommutativity. The goal is to be able to predict results of simple experiments involving signal propagation directly from commutation relations. A model predicting an energy dependence of the speed of photons of the order E/E_Planck is discussed in detail. Such effects can be detectable by the

D. Falcone

By inverting the seesaw formula we determine the heavy neutrino mass matrix. The impact on the baryogenesis via leptogenesis and the radiative lepton decays in supersymmetric models is described. Links to neutrinoless double beta decay are also briefly discussed. The analysis leads to two distinct matrix models. One has small mixings while the other has one

Igor Jex, Erika Andersson, Anthony Chefles

We investigate how to determine whether the states of a set of quantum systems are identical or not. This paper treats both error-free comparison, and comparison where errors in the result are allowed. Error-free comparison means that we aim to obtain definite answers, which are known to be correct, as often as possible. In general, we will have to accept al

M. Wilkinson, B. Mehlig

We analyse the motion of a system of particles subjected a random force fluctuating in both space and time, and experiencing viscous damping. When the damping exceeds a certain threshold, the system undergoes a phase transition: the particle trajectories coalesce. We analyse this transition by mapping it to a Kramers problem which we solve exactly. In the li

Hideo Aoki

An overview is given on how superconductivity with anisotropic pairing can be realised from repulsive electron-electron interaction. (i) We start from the physics in one dimension, where the Tomonaga-Luttinger theory predicts that, while there is no superconducting phase for the repulsive case for a single chain, the phase does exists in ladders with the num

Guo-meng Zhao

We have analyzed data from angle resolved photoemission spectroscopy, Fourier transform scanning tunnelling spectroscopy, and low-temperature thermal conductivity for optimally doped Bi_2Sr_2CaCu_2O_8+y in order to discriminate between d-wave and extended s-wave pairing symmetry. The combined data are inconsistent with d-wave symmetry, but quantitatively con

Arnold I. Boothroyd, Peter G. Martin, Michael R. Peterson

The interaction potential energy surface (PES) of He-H2 is of great importance for quantum chemistry, as the simplest test case for interactions between a molecule and a closed-shell atom. It is also required for a detailed understanding of certain astrophysical processes, namely collisional excitation and dissociation of H2 in molecular clouds, at densities

David R. Law, Steven R. Majewski, Michael F. Skrutskie, John M. Carpenter

J, H, and K_S band data from the Two Micron All-Sky Survey (2MASS) are used to study the effects of differential reddening across the three massive Galactic globular clusters Omega Centauri, NGC 6388, and NGC 6441. Evidence is found that variable extinction may produce false detections of tidal tails around Omega Centauri. We also investigate what appears to

Elena R. Loubenets

We introduce a new mathematical framework for the probabilistic description of an experiment upon a system of any type in terms of initial information representing this system. Based on the notions of an information state, an information state space and a generalized observable, this general framework covers the description of a wide range of experimental si

T. Briant, P. F. Cohadon, A. Heidmann, M. Pinard

We present an experimental study of the internal mechanical vibration modes of a mirror. We determine the frequency repartition of acoustic resonances via a spectral analysis of the Brownian motion of the mirror, and the spatial profile of the acoustic modes by monitoring their mechanical response to a resonant radiation pressure force swept across the mirro

Michele Pavon

We seek to complement Nelson&#39;s work on the two-slit experiment by showing that the two-slit process, whose density exhibits the characteristic interference pattern, may be obtained as the model after the beam has reached the screen by means of a variational mechanism. The one-slit process, modeling the beam before it reaches the screen, plays the role of

V. I. Man&#39;ko, V. A. Sharapov, E. V. Shchukin

The tomographic probability distribution is used to decribe the kinetic equations for open quantum systems. Damped oscillator is studied. Purity parameter evolution for different damping regime is considered.

O. Akhavan, A. T. Rezakhani, M. Golshani

We have presented a theoretical extended version of dense coding protocol using entangled position state of two particles shared between two parties. A representation of Bell states and the required unitary operators are shown utilizing symmetric normalized Hadamard matrices. In addition, some explicit and conceivable forms for the unitary operators are pres

Jeremy Butterfield

This paper gives a technically elementary treatment of some aspects of Hamilton-Jacobi theory, especially in relation to the calculus of variations. The second half of the paper describes the application to geometric optics, the optico-mechanical analogy and the transition to quantum mechanics. Finally, I report recent work of Holland providing a Hamiltonian

Koen J. van Vlaenderen

Within the framework of Classical Electrodynamics (CED) it is common practice to choose freely an arbitrary gauge condition with respect to a gauge transformation of the electromagnetic potentials. The Lorenz gauge condition allows for the derivation of the inhomogeneous potential wave equations (IPWE), but this also means that scalar derivatives of the elec

Predrag Miocinovic, Peter Niessen

To maximize the accuracy of background simulation and event reconstruction, high-energy neutrino telescopes require detailed knowledge of light propagation over a large volume of detection medium. If light scattering and absorption leng ths in the medium are of the same scale as the detector size, this problem can only be handled numerically. Any inhomogenei

Guillaume Huot, Laurence Mechin, Daniel Bloyet

Mo, Pt, Pt/Mo and Pt/Ti thin films have been deposited onto Si and SiO2 substrates by RF sputtering and annealed in the YBa2Cu3O7-d growth conditions. The effect of annealing on the sheet resitance of unpatterned layers was measured. A Pt-based multilayered metallization for the PMOS devices was proposed and tested for the monolithic integration of PMOS devi

N. L. Harshman

Several graphical representations of the mass and width spectrum of unstable subatomic particles are presented. Such plots are useful tools for introducing students to the particle zoo and provide students an alternate way to organize conceptually what can seem like an overwhelming amount of data. In particular, such graphs highlight phenomenological feature

Bruno Guillet, Didier Robbes, Laurence Mechin

In electrically substituted radiometers, the ultra low noise control of the temperature is required. In this framework, we present results dedicated to the temperature regulation of copper plates, 3 cm diameter and 1 mm thick, using YBa2Cu3O7-d (YBCO) transition edge sensors (TES). One of the TES was used as the active thermometer of the temperature control

Tomislav Ivezic

In this paper we present the formulation of relativistic electrodynamics (independent of the reference frame and of the chosen system of coordinates in it) that uses the Faraday bivector field F. This formulation with F field is a self-contained, complete and consistent formulation that dispenses with either electric and magnetic fields or the electromagneti

Jian Qi Shen

During the last three decades, photon rest mass problem captured special attention of many investigators who have reported several experimental upper limits on the photon mass by using various methods. More recently, Luo et al. obtained the most new upper limit on photon rest mass of $1.2\times 10^{-54}$ Kg by means of rotating torsion balance experiment. Al

Pasi Huovinen

I review how hydrodynamical flow is related to the observed flow in ultrarelativistic heavy ion collisions and how initial conditions, equation of state and freeze-out temperature affect flow in hydrodynamical models.

J. Honzatko, V. A. Khitrov, C. Panteleev, A. M. Sukhovoj

Transition energies and intensities of 454 two-step cascades following thermal neutron capture in Sn-117 have been measured. These data allowed us to make more precise and considerably extend the earlier obtained decay scheme of the Sn-118 nucleus. Autocorrelation analysis of the excitation spectrum of intermediate levels of the most intense cascades allowed

T. C. Black, P. R. Huffman, D. L. Jacobson, W. M. Snow

We have performed the first high precision measurement of the coherent neutron scattering length of deuterium in a pure sample using neutron interferometry. We find b_nd = (6.665 +/- 0.004) fm in agreement with the world average of previous measurements using different techniques, b_nd = (6.6730 +/- 0.0045) fm. We compare the new world average for the nd coh

Toshiyuki Gotoh, Robert H. Kraichnan

Fully-developed incompressible Navier-Stokes turbulence in three dimensions is a dissipative dynamical system that exhibits strong departure from absolute equilibrium. Nevertheless, several kinds of representation by Tsallis equilibria have been proposed. The symmetry of the contributions to the kinetic energy from the degrees of freedom of the flow must be

A. G. Rossberg, K. Bartholome, J. Timmer

A new method for extracting the phase of oscillations from noisy time series is proposed. To obtain the phase, the signal is filtered in such a way that the filter output has minimal relative variation in the amplitude (MIRVA) over all filters with complex-valued impulse response. The argument of the filter output yields the phase. Implementation of the algo

A G Rossberg

A definition of frequency (cycles per unit-time) based on an approximate reconstruction of the phase-space trajectory of an oscillator from a signal is introduced. It is shown to be invariant under linear filtering, and therefore inaccessible by spectral methods. The effect of filtering on frequency in cases where this definition does not perfectly apply is