August 2002 arXiv papers — page 21

J. B. Griffiths, J. Podolsky, P. Docherty

The Robinson-Trautman type N solutions, which describe expanding gravitational waves, are investigated for all possible values of the cosmological constant Lambda and the curvature parameter epsilon. The wave surfaces are always (hemi-)spherical, with successive surfaces displaced in a way which depends on epsilon. Explicit sandwich waves of this class are s

V. N. Melnikov, V. D. Ivashchuk

The relations for G-dot in multidimensional model with Ricci-flat internal space and multicomponent perfect fluid are obtained. A two-component example: dust + 5-brane, is considered.

J. J. Halliwell

The development of quantum cosmology, in which Stephen Hawking played a crucial role, has frequently encountered substantial conceptual and technical difficulties related to the problem of time in quantum gravity and to general issues concerning the foundations of quantum theory. In this contribution to Stephen's 60th Birthday Conference, I describe some

L. B. Savchenko, V. A. Savchenko, G. M. Vereshkov

The only known general base to eliminate the vacuum divergencies of quantized matter fields in quantum geometrodynamics is the fermion-boson supersymmetry. The topological effect of the closed Universe -- discretization of the vacuum fluctuations spectra -- allows to formulate the conditions of cancellation of the divergencies. In the center of attention of

Yves Moinard

About ten years ago, various notions of preferential entailment have been introduced. The main reference is a paper by Kraus, Lehmann and Magidor (KLM), one of the main competitor being a more general version defined by Makinson (MAK). These two versions have already been compared, but it is time to revisit these comparisons. Here are our three main results:

W. Chen

By far, the fractional derivative model is mainly related to the modelling of complicated solid viscoelastic material. In this study, we try to build the fractional derivative PDE model for broadband ultrasound propagation through human tissues.

Duccio Medini, A. Widom

The soft condensed matter of biological organisms exhibits atomic motions whose properties depend strongly on temperature and hydration conditions. Due to the superposition of rapidly fluctuating alternative motions at both very low temperatures (quantum effects) and very high temperatures (classical Brownian motion regime), the dimension of an atomic ``path

Magnus Paulsson, Ferdows Zahid, Supriyo Datta

In recent years, several experimental groups have reported measurements of the current-voltage (I-V) characteristics of individual or small numbers of molecules. Our purpose in this chapter is to provide an intuitive explanation for the observed I-V characteristics using simple models to illustrate the basic physics. In contrast to the MOSFET, whose I-V is l

T. K. Kim, H. Rosner, S. -L. Drechsler, Z. Hu

Experimental and theoretical studies of the unoccupied electronic structure of CaCu2O3 single crystals have been performed using polarization-dependent x-ray absorption spectroscopy and band structure calculations. The measured hole distribution shows an unusual large number of holes in orbitals parallel to the interlayer direction which is in agreement with

Hamza Balci, V. N. Smolyaninova, P. Fournier, Amlan Biswas

The specific heat of electron-doped Pr_{1.85} Ce_{0.15} CuO_4 single crystals is reported for the temperature range 2 - 10 K and magnetic field range 0 - 10 T. A non-linear magnetic field dependence is observed for the field range 0 - 2 T. Our data supports a model with lines of nodes in the gap function of these superconductors. Theoretical calculations of

I. Tifrea, J. A. Budagosky Marcilla, J. J. Rodriguez-Nunez

We reconsider the Ginzburg-Landau expansion for the case of a non-Fermi liquid superconductor. We obtain analytical results for the Ginzburg-Landau functional in the critical region around the superconducting phase transition, T <= T_c, in two special limits of the model, i.e., the spin-charge separation case and the anomalous Fermi liquid case. For both cas

H. -S. Sim, H. Schomerus

We study shot noise for generic quantum dots coupled to two leads and allow for an arbitrary strength of diffractive impurity scattering inside the dots. The ballistic quantum dots possess a mixed classical phase space, where regular and chaotic regions coexist. In absence of disorder, the noise is systematically suppressed below the universal value of fully

Simon W. Marlow, Peter D. Olmsted

We study the effect of shear flow on the entropic Helfrich interaction in lyotropic surfactant smectic fluids. Arguing that flow induces an effective anisotropic surface tension in bilayers due to a combination of intermonolayer friction, bilayer collisions and convection, we calculate the reduction in fluctuations and hence the renormalised change in effect

D. Fay, J. Appel

We calculate the effect of scattering on the static, exchange enhanced, spin susceptibility and show that in particular spin orbit scattering leads to a reduction of the giant moments and spin glass freezing temperature due to dilute magnetic impurities. The harmful spin fluctuation contribution to the intra-grain pairing interaction is strongly reduced open

A. Hotta, E. M. Terentjev

We study the linear dynamic mechanical response of monodomain nematic liquid crystalline elastomers under shear in the geometry that allows the director rotation. The aspects of time-temperature superposition are discussed at some length and Master Curves are obtained between the glassy state and the nematic transition temperature Tni. However, the time-temp

A. E. Karakozov, E. G. Maksimov, O. V. Dolgov

The interrelation between the condensation energy and the optical sum rules has been investigated. It has been shown that the so called &#39;partial&#39; sum rule violation is related mainly to a temperature dependence of the relaxation rate rather than to the appearance of superconductivity itself. Moreover, we demonstrate that the experimental data on the

Tanniemola B. Liverpool

Using a simple model, we study the fluctuating dynamics of inextensible, semiflexible polar filaments interacting with active and directed force generating centres such as molecular motors. Taking into account the fact that the activity occurs on time-scales comparable to the filament relaxation time, we obtain some unexpected differences between both the st

A. Podesta&#39;, G. Fantoni, P. Milani, M. Ragazzi

We have characterized the frictional properties of nanostructured (ns) carbon films grown by Supersonic Cluster Beam Deposition (SCBD) via an Atomic Force-Friction Force Microscope (AFM-FFM). The experimental data are discussed on the basis of a modified Amonton&#39;s law for friction, stating a linear dependence of friction on load plus an adhesive offset a

Dhruba Banerjee, Suman Kumar Banik, Bidhan Chandra Bag, Deb Shankar Ray

Based on a true phase space probability distribution function and an ensemble averaging procedure we have recently developed [Phys. Rev. E 65, 021109 (2002)] a non-Markovian quantum Kramers&#39; equation to derive the quantum rate coefficient for barrier crossing due to thermal activation and tunneling in the intermediate to strong friction regime. We comple

Kunal K. Das

We analyze the phase stability and the response of a mixture of bosons and spin-polarized fermions in one dimension (1D). Unlike in 3D, phase separation happens for low fermion densities. The dynamics of the mixture at low energy is independent of the spin-statistics of the components, and zero-sound-like modes exist that are essentially undamped.

Takashi Kimura, Yuji Zenitani, Kazuhiko Kuroki, Ryotaro Arita

Plaquette lattices with each unit cell containing multiple atoms are good candidates for disconnected Fermi surfaces, which are shown by Kuroki and Arita to be favorable for spin-flucutation mediated superconductivity from electron repulsion. Here we find an interesting example in a tetramer lattice where the structure within each unit cell dominates the nod

Marian Boguna, Romualdo Pastor-Satorras, Alessandro Vespignani

Random scale-free networks have the peculiar property of being prone to the spreading of infections. Here we provide an exact result showing that a scale-free connectivity distribution with diverging second moment is a sufficient condition to have null epidemic threshold in unstructured networks with either assortative or dissortative mixing. Connectivity co

O. Morsch, J. H. Müller, D. Ciampini, M. Cristiani

The mode structure of a Bose-Einstein condensate non-adiabatically loaded into a one-dimensional optical lattice is studied by analyzing the visibility of the interference pattern as well as the radial profile of the condensate after a time-of-flight. A simple model is proposed that predicts the short-time decrease of the visibility as a function of the cond

W. V. Pogosov, A. L. Rakhmanov, V. V. Moshchalkov

The vortex patterns stabilized by the square array of artificial pinning sites with a tunable pinning strength are studied by using a phenomenological approach in the London limit. The transitions between pinned and deformed triangular lattices are analyzed as a function of the amplitude of the vortex-pinning site interaction and the characteristic length-sc

V. A. Moskalenko, P. Entel, M. Marinaro, D. F. Digor

We investigate the interaction of strongly correlated electrons with phonons in the frame of the Hubbard-Holstein model. The electron-phonon interaction is considered to be strong and is an important parameter of the model besides the Coulomb repulsion of electrons and band filling. This interaction with the nondispersive optical phonons has been transformed

R. Podgornik, P. L. Hansen

We investigate interactions between an elastic membrane and a substrate characterized by quenched positional disorder in the height function. We show that the positional disorder transforms the standard secondary DLVO minimum into two separate states: the hovering state characterized by a planar membrane at a finite separation from the interface and a pinned

D. J. Gonzalez, L. E. Gonzalez, J. M. Lopez, M. J. Stott

The dynamic structure factor of the 7Li0.61Na0.39 liquid alloy at T=590 K has been calculated by ab initio molecular dynamics simulations using 2000 particles. For small wavevectors, 0.15 <= q/A-1 <= 1.6, we find clear side peaks in the partial dynamic structure factors. Whereas for q <= 0.25 A-1 the peak frequencies correspond to the hydrodynamic sound disp

Shinji Watanabe, Masatoshi Imada

The ground-state properties of the two-dimensional Hubbard model with nearest-neighbor and next-nearest-neighbor hoppings at half filling are studied by the path-integral-renormalization-group method. The nonmagnetic-insulator phase sandwiched by the the paramagnetic-metal phase and the antiferromagnetic-insulator phase shows evidence against translational s

John E. Carlstrom, Gilbert P. Holder, Erik D. Reese

The Sunyaev-Zel&#39;dovich effect (SZE) provides a unique way to map the large-scale structure of the universe as traced by massive clusters of galaxies. As a spectral distortion of the cosmic microwave background, the SZE is insensitive to the redshift of the galaxy cluster, making it well-suited for studies of clusters at all redshifts, and especially at r

G. C. Dewangan, K. P. Singh, K. F. Gunn, A. M. Newsam

In order to study systematically the soft X-ray emission of Active Galactic Nuclei (AGNs) at medium to high redshifts, we have analyzed ROSAT PSPC and HRI data of QSOs at 0.26<z<3.43 selected from the second deepest ROSAT PSPC survey carried out in 1991-1993 by McHardy et al. (1998). Our sample of 22 type 1 QSOs is nearly complete above a flux limit of 1.4e-

C. L. Williams, N. Panagia, S. D. Van Dyk, C. K. Lacey

We present observations of the radio emission from the unusual SN 1988Z made with the VLA from 385 to 4,438 days after explosion. SN 1988Z is the most distant radio supernova ever detected. The radio light curves are well-described by a model involving the blastwave interacting with a high-density circumstellar cocoon, which consists almost entirely of clump

C. Gallart, M. Zoccali, G. Bertelli, C. Chiosi

This is the first of a series of three papers devoted to the calibration of a few parameters of crucial importance in the modeling of the evolution of intermediate-mass stars, with special attention to the amount of convective core overshoot. To this end we acquired deep V and R photometry for three globular clusters of the Large Magellanic Cloud (LMC), name

J. C. Lee, C. S. Reynolds, R. Remillard, N. S. Schulz

The Chandra AO1 HETGS observation of the micro-quasar GRS 1915+105 in the low hard state reveals (1) neutral K absorption edges from Fe, Si, Mg, and S in cold gas, and (2) highly ionized (Fe XXV and Fe XXVI) absorption attributed to a hot disk, disk wind, or corona. The neutral edges reveal anomalous Si and Fe abundances which we attribute to surrounding col

Gary Steigman

Of the light nuclides observed in the universe today, D, 3He, 4He, and 7Li are relics from its early evolution. The primordial abundances of these relics, produced via Big Bang Nucleosynthesis (BBN) during the first half hour of the evolution of the universe provide a unique window on Physics and Cosmology at redshifts of order 10^10. Comparing the BBN-predi

Ted von Hippel, Carlos Allende Prieto, Chris Sneden

Stellar spectroscopic classification has been successfully automated by a number of groups. Automated classification and parameterization work best when applied to a homogeneous data set, and thus these techniques primarily have been developed for and applied to large surveys. While most ongoing large spectroscopic surveys target extragalactic objects, many

David E. Trilling, Jonathan I. Lunine, Willy Benz

We present a statistical study of the post-formation migration of giant planets in a range of initial disk conditions. For given initial conditions we model the evolution of giant planet orbits under the influence of disk, stellar, and mass loss torques. We determine the mass and semi-major axis distribution of surviving planets after disk dissipation, for v

E. Piconcelli, M. Cappi, L. Bassani, F. Fiore

We present a spectroscopic study of 41 hard X-ray sources detected serendipitously with high significance (> 5 sigma in the 2-10 keV band) in seven EPIC performance/verification phase observations. The large collecting area of EPIC allows us to explore the spectral properties of these faint hard X-ray sources with 2< F_{2-10} < 80 x 10^{-14} erg cm^{-2}s^{-1

Aurelien Barrau

Antiprotons and antideuterons are considered as probes to look for primordial black holes in our Galaxy. I give a brief overview of the latest developments on the subject.

Bianca M. Poggianti

In this paper I present some recent and new results regarding the effects of the cluster environment on the star formation history of galaxies. Three main aspects are discussed: the differences in the stellar population ages of cluster ellipticals and S0 galaxies; the comparison of the spectroscopic properties of galaxies in distant clusters and in Coma; and

M. Soida, R. Beck, M. Urbanik, J. Braine

We present three-frequency VLA observations of the flocculent spiral galaxy NGC 4414 made in order to study the magnetic field structure in absence of strong density wave flows. NGC 4414 shows a regular spiral pattern of observed polarization B-vectors with a radial component comparable in strength to the azimuthal one. The average pitch angle of the magneti

J. Huovelin, J. Schultz, O. Vilhu, D. Hannikainen

(Abridged) Spectral and time variability analysis of the region of the hard X-ray transient EXS 1737.9-2952 near the Galactic Centre (GC), using data from the Narrow Field Instruments of BeppoSAX is reported. The main results are the MECS spectra of the 10 identified sources. Fluxes obtained with spectral fits are 1.7-4.8E-12 erg / cm2 s. The absorption is i

Travis S. Metcalfe

White Dwarf Research Corporation is a 501(c)(3) non-profit organization dedicated to scientific research and public education on topics relevant to white dwarf stars. It was founded in 1999 in Austin, Texas to help fulfill the need for an alternative research center where scarce funding dollars could be used more efficiently, and to provide a direct link bet

Yong -Cheol Kim, Pierre Demarque, Sukyoung K. Yi, David R. Alexander

We present a new set of isochrones in which the effect of the alpha-element enhancement is fully incorporated. These isochrones are an extension of the already published set of YY Isochrones (Yi et al. 2001: Paper 1), constructed for the scaled-solar mixture. As in Paper 1, helium diffusion and convective core overshoot have been taken into account.The range

T. Yamada, Y. Koyama, F. Nakata, M. Kajisawa

We have obtained a new high-resolution K&#39;-band image of the central region of the rich X-ray cluster RX J0848.9+4452 at z=1.26. We found that the brightest cluster galaxy (BCG) in the cluster is clearly separated into two distinct objects. Whereas the optical to near-infrared colors of the objects are consistent with the predictions of passive evolution

Thierry Passot, Enrique Vazquez-Semadeni

We discuss magnetic pressure and density fluctuations in strongly turbulent isothermal MHD flows in &#34;1+2/3&#34; dimensions. We first consider &#34;simple&#34; nonlinear MHD waves, which allow us show that the slow and fast modes have different asymptotic dependences of the magnetic pressure B^2 vs. rho. For the slow mode, B^2 ~= c_1-c_2 rho, while for th

J. W. Dunn, D. Blume, Bogdan Borca, B. E. Granger

Spectroscopic studies of few-body systems at ultracold temperatures provide valuable information that often cannot be extracted in a hot environment. Considering a pair of atoms, we propose a cooling mechanism that makes use of a scattering Feshbach resonance. Application of a series of time-dependent magnetic field ramps results in the situation in which ei

Edward L. Hamilton, Chris H. Greene

To describe multiple interacting fragmentation continua, we develop a method in which the vibrational channel functions obey outgoing wave Siegert boundary conditions. This paper demonstrates the utility of the Siegert approach, which uses channel energy eigenvalues that possess a negative imaginary part. The electron scattering energy in each such channel i

J. M. Miller, R. Wijnands, M. Mendez, E. Kendziorra

We present an analysis of the first high-resolution spectra measured from an accretion-driven millisecond X-ray pulsar in outburst. We observed XTE J1751-305 with XMM-Newton on 2002 April 7 for approximately 35 ksec. Using a simple absorbed blackbody plus power-law model, we measure an unabsorbed flux of (6.6 +/- 0.1) * 10^(-10) erg/cm^2/s (0.5--10.0 keV). A

S. Jeon, J. Jalilian-Marian, I. Sarcevic

We present results for inclusive $π^0$ production in proton-proton and in Au-Au at RHIC energy $\sqrt s=200$ GeV. We use next-to-leading order perturbative QCD calculation and we include nuclear effects such as parton energy loss and nuclear shadowing. We consider the ratio of $π^0$ distribution in Au-Au and p-p collisions for $p_T > 3$ GeV for three cases o

Mark Byrne, Christopher Kolda, Jason E. Lennon

We re-examine the bounds on supersymmetric particle masses in light of the new E821 data on the muon anomalous magnetic moment and the revised theoretical calculations of its hadronic contributions. The current experimental excess is either 1.5 sigma or 3.2 sigma depending on whether e+e- or tau-decay data are used in the theoretical calculations for the lea

Boaz Tsaban

Whereas the Gerlits-Nagy gamma-property is strictly weaker than the Galvin-Miller strong gamma-property, the corresponding strong notions for the Menger, Hurewicz, Rothberger, Gerlits-Nagy (*), Arkhangel&#39;skii and Sakai properties are equivalent to the original ones. The main result is that almost each of these properties admits the game theoretic charact

Xavier Bekaert, Nicolas Boulanger

Using a mathematical framework which provides a generalization of the de Rham complex (well-designed for p-form gauge fields), we study the gauge structure and duality properties of theories for free gauge fields transforming in arbitrary irreducible representations of GL(D,R). We prove a generalization of the Poincare lemma which enables us to solve the abo

H. M. Fried, Y. Gabellini

A physically reasonable model is introduced in order to estimate, in a functional way, the vast number of distinct graphs which are conventionally neglected in eikonal scattering models that lead to total cross sections increasing with energy in the form of the Froissart bound.

Ya. S. Greenberg, A. Izmalkov, M. Grajcar, E. Il&#39;ichev

Time-domain observations of coherent oscillations between quantum states in mesoscopic superconducting systems were so far restricted to restoring the time-dependent probability distribution from the readout statistics. We propose a new method for direct observation of Rabi oscillations in a phase qubit. The external source, typically in GHz range, induces t

Robert S. Whitney, Yuval Gefen

We investigate the effect of the environment on a Berry phase measurement involving a spin-half. We model the spin+environment using a biased spin-boson Hamiltonian with a time-dependent magnetic field. We find that, contrary to naive expectations, the Berry phase acquired by the spin can be observed, but only on timescales which are neither too short nor ve

J. M. Alcala&#39;, M. Radovich, R. Silvotti, M. Pannella

The Capodimonte Deep Field (OACDF) is a multi-colour imaging survey on two 0.5x0.5 square degree fields performed in the BVRI bands and in six medium-band filters (700 - 900 nm) with the Wide Field Imager (WFI) at the ESO 2.2 m telescope at La Silla, Chile. In this contribution the adopted strategies for the OACDF data reduction are discussed. Preliminary sc

Franz X. Bronold, Ivar Martin, Avadh Saxena, Darryl L. Smith

We present a theoretical investigation of the magnetic field dependence of the longitudinal ($T_1$) and transverse ($T_2$) spin relaxation times of conduction band electrons in n-type III-V semiconductors. In particular, we find that the interplay between the Dyakonov-Perel process and an additional spin relaxation channel, which originates from the electron

Dipak Munshi, Anthony D. Challinor, Olivier Doré, Daniel J. Mortlock

This paper has been withdrawn. It was an early draft submitted prematurely in error. A complete version is to be submitted shortly.

Dafne Guetta, Jonathan Granot

We consider GRBs that occur inside pulsar wind bubbles (PWBs), in the context of the supranova model, where initially a supernova explosion takes place, leaving behind a supra-massive neutron star (SMNS), which eventually loses its rotational energy and collapses to a black hole, triggering a GRB explosion. The most natural mechanism by which the SMNS can lo

G. E. Volovik

An analog of black hole can be realized in the low-temperature laboratory. The horizon can be constructed for the `relativistic&#39; ripplons (surface waves) living on the brane. The brane is represented by the interface between two superfluid liquids, 3He-A and 3He-B, sliding along each other without friction. Similar experimental arrangement has been recen

D. Grumiller, W. Kummer, D. V. Vassilevich

The virtual black hole phenomenon, which has been observed previously in specific models, is established for generic 2D dilaton gravity theories with scalar matter. The ensuing effective line element can become asymptotically flat only for two classes of models, among them spherically reduced theories and the string inspired dilaton black hole (CGHS model).

V. V. Skalozub, A. V. Strelchenko

The vacuum state of SU(3) gluodynamics at high temperature is investigated. A consistent approach including the calculation of either the spontaneously generated constant chromomagnetic isotopic $H_{3}$ and hypercharge $H_{8}$ fields or the polarization operator of charged gluons in this background is applied. It is shown within the effective potential inclu

J. Berges, J. Serreau

We present the first study of parametric resonance in quantum field theory from a complete next-to-leading order calculation in a 1/N-expansion of the 2PI effective action, which includes scattering and memory effects. We present a complete numerical solution for an O(N)-symmetric scalar theory and provide an approximate analytic description of the nonlinear

J. Gutowski, G. Papadopoulos

We investigate the four-dimensional supergravity theory obtained from the compactification of eleven-dimensional supergravity on a smooth manifold of G_2 holonomy. We give a new derivation for the Kaehler potential associated with the scalar kinetic term of the N=1 four-dimensional theory. We then examine some solutions of the four-dimensional theory which a

O. A. Castro-Alvaredo, A. Fring, C. Figueira de Morisson Faria

Within a one particle approximation of the Dirac equation we investigate a defect system in a quantum wire. We demonstrate that by minimally coupling a laser field of frequency omega to such an impurity system, one may generate harmonics of multiples of the driving frequency. In a multiple defect system one may employ the distance between the defects in orde

E. Deotto, E. Gozzi, D. Mauro

In this paper we analyze two different functional formulations of classical mechanics. In the first one the Jacobi fields are represented by bosonic variables and belong to the vector (or its dual) representation of the symplectic group. In the second formulation the Jacobi fields are given as condensates of Grassmannian variables belonging to the spinor rep

Yeong Gyun Kim, Takeshi Nihei, Leszek Roszkowski, Roberto Ruiz de Austri

We derive the allowed ranges of the spin--independent interaction cross section $\sigsip$ for the elastic scattering of neutralinos on proton for wide ranges of parameters of the general Minimal Supersymmetric Standard Model. We investigate the effects of the lower limits on Higgs and superpartner masses from colliders, as well as the impact of constraints f

E. Deotto, E. Gozzi, D. Mauro

In this paper we study the Hilbert space structure underlying the Koopman-von Neumann (KvN) operatorial formulation of classical mechanics. KvN limited themselves to study the Hilbert space of zero-forms that are the square integrable functions on phase space. They proved that in this Hilbert space the evolution is unitary for every system. In this paper we

Peter Hoyer, Robert Spalek

We demonstrate that the unbounded fan-out gate is very powerful. Constant-depth polynomial-size quantum circuits with bounded fan-in and unbounded fan-out over a fixed basis (denoted by QNCf^0) can approximate with polynomially small error the following gates: parity, mod[q], And, Or, majority, threshold[t], exact[q], and Counting. Classically, we need logar

F. Lefloch, C. Hoffmann, M. Sanquer, D. Quirion

We performed low temperature shot noise measurements in Superconductor (TiN) - strongly disordered normal metal (heavily doped Si) weakly transparent junctions. We show that the conductance has a maximum due to coherent multiple reflections at low energy and that shot noise is then twice the Poisson noise (S=4eI). The shot noise changes to the normal value (

Yoshiaki Koma

The [U(1)]^{N-1} dual Ginzburg-Landau (DGL) theory as a low-energy effective theory of Abelian-projected SU(N) gauge theory is formulated in a Weyl symmetric way. The string tensions of flux-tube solutions of the DGL theory associated with color-electric charges in various representations of SU(N) are calculated analytically at the border between type-I and

Navin Khaneja, Timo Reiss, Burkhard Luy, Steffen J. Glaser

Experiments in coherent spectroscopy correspond to control of quantum mechanical ensembles guiding them from initial to final target states. The control inputs (pulse sequences) that accomplish these transformations should be designed to minimize the effects of relaxation and to optimize the sensitivity of the experiments. For example in nuclear magnetic res

George Svetlichny

We comment on the article of Ch. Simon, V. Buzek and N. Gisin: ``No-Signaling Condition and Quantum Dynamics&#39;&#39;, Phys. Rev. Lett. 87 (2001) 170405, which argues that linearity of quantum mechanics follows from lack of superluminal signals and some usual hypotheses about measurements. We argue that such assumptions in the end are ineffective as an expl

Zbigniew A. Nowacki

It is known that superluminal transmission of information and energy contradicts Einstein&#39;s relativity. Here we announce an unusual TOE called &#39;nature theory&#39; in which impossible things become possible. We present the scheme of an apparatus for sending signals over arbitrarily large distances with speeds arbitrarily exceeding the light speed in v

Minoru Horibe, Takaaki Hashimoto, Akihisa Hayashi

We show that the Fano operator for one dimensional quantum system is uniquely determined by assuming the reasonable behavior under translation and parity transformation on phase space. Contrarily, for the system with lattice phase space the same procedure does not work.

Matthew J. Donald

It has been suggested, on the one hand, that quantum states are just states of knowledge; and, on the other, that quantum theory is merely a theory of correlations. These suggestions are confronted with problems about the nature of psycho-physical parallelism and about how we could define probabilities for our individual future observations given our individ

Alexander Barg

We extend a low-rate improvement of the random coding bound on the reliability of a classical discrete memoryless channel to its quantum counterpart. The key observation that we make is that the problem of bounding below the error exponent for a quantum channel relying on the class of stabilizer codes is equivalent to the problem of deriving error exponents

Mehran Kardar, A. Zee

Barn owls hunt in the dark by using cues from both sight and sound to locate their prey. This task is facilitated by topographic maps of the external space formed by neurons (e.g., in the optic tectum) that respond to visual or aural signals from a specific direction. Plasticity of these maps has been studied in owls forced to wear prismatic spectacles that

S. Bellucci, S. Bini, V. M. Biryukov, Yu. A. Chesnokov

We present an idea for creation of a crystalline undulator and report its first realization. One face of a silicon crystal was given periodic micro-scratches (trenches) by means of a diamond blade. The X-ray tests of the crystal deformation due to given periodic pattern of surface scratches have shown that a sinusoidal shape is observed on both the scratched

Ionel Lazanu, Sorina Lazanu

Silicon detectors in particle physics experiments at the new accelerators or in space missions for physics goals will be exposed to extreme radiation conditions. The principal obstacles to long-term operation in these environments are the changes in detector parameters, consequence of the modifications in material properties after irradiation. The phenomenol

Randall D. Peters

A modification of Coulomb&#39;s law of friction uses a variable coefficient of friction that depends on a power law in the energy of mechanical oscillation. Through the use of three different exponents: 0, 1/2 and 1; all commonly encountered non-viscous forms of damping are accommodated. The nonlinear model appears to yield good agreement with experiment in

Florin Diacu, Manuele Santoprete

We study the global flow of the anisotropic Manev problem, which describes the planar motion of two bodies under the influence of an anisotropic Newtonian potential with a relativistic correction term. We first find all the heteroclinic orbits between equilibrium solutions. Then we generalize the Poincare&#39;-Melnikov method and use it to prove the existenc

M. A. Jafarizadeh, S. Behnia

Hierarchy of one-parameter families of chaotic maps with an invariant measure have been introduced, where their appropriate coupling has lead to the generation of some coupled chaotic maps with an invariant measure. It is shown that these chaotic maps (also the coupled maps) do not undergo any period doubling or period-n-tupling cascade bifurcation to chaos,

Abhik Basu

The turbulent dynamo effect, which describes the generation of magnetic fields in astrophysical objects, is described by the dynamo equation. This, in the kinematic (linear) approximation gives an unbounded exponential growth of the long wavelength part of the magnetic fields. Here we, in a systematic diagrammatic, perturbation theory, show how non-linear ef

Karen E. Daniels, Richard J. Wiener, Eberhard Bodenschatz

We investigate a novel bursting state in inclined layer thermal convection in which convection rolls exhibit intermittent, localized, transverse bursts. With increasing temperature difference, the bursts increase in duration and number while exhibiting a characteristic wavenumber, magnitude, and size. We propose a mechanism which describes the duration of th

M. R. Paul, M. C. Cross, P. F. Fischer

Pattern formation in Rayleigh-Benard convection in a large-aspect-ratio cylinder with a radial ramp in the plate separation is studied analytically and numerically by performing numerical simulations of the Boussinesq equations. A horizontal mean flow and a vertical large scale counterflow are quantified and used to understand the pattern wavenumber. Our res

S. De Nicola, R. Fedele, M. A. Man&#39;ko, V. I. Man&#39;ko

We develope the tomographic representation ofwavefunctions which are solutions of the generalizednonlinear Schrodinger equation (NLSE) and show itsconnection with the Weyl--Wigner map.In particular, this theory is applied tothe envelope solitons, where tomograms for envelopebright solitons of a wide family of modified NLSE arepresented and numerically evalue

Yum-Tong Siu, Sai-Kee Yeung

This is an addendum to our earlier paper on the defect of an ample divisor of an abelian variety. It modifies an argument of the original paper to handle one difficulty there. At the same time the modification improves the result in the original paper by replacing the counting function by one truncated at a multiplicity given by an explicit function of the d

Cesar Camacho, Hossein Movasati

The systematic study of neighborhoods of analytic varieties was started by H. Grauert in his celebrated article 1962. In that article he considers a manifold X and a negatively embedded submanifold A subset X. He introduces n-neighborhood, n in N, of A and studies when an isomorphism of two n-neighborhoods can be extended to an isomorphism of (n+1)-neighborh

Noam D. Elkies

For nonzero rational D, which may be taken to be a squarefree integer, let E_D be the elliptic curve Dy^2=x^3-x over Q arising in the &#34;congruent number&#34; problem. It is known that the L-function of E_D has sign -1, and thus odd analytic rank, if and only if |D| is congruent to 5, 6, or 7 mod 8. For such D, we expect by the conjecture of Birch and Swin

Th. Schlumprecht

We present partial results to the following question: Does every infinite dimensional Banach space have an infinite dimensional subspace on which one can define an operator which is not a compact perturbation of a scalar multiplication?

Sonia Natale

We show that a semisimple Hopf algebra A is group theoretical if and only if its Drinfeld double is a twisting of the Dijkgraaf-Pasquier-Roche quasi-Hopf algebra D^{omega}(Sigma), for some finite group Sigma and some 3-cocycle omega on Sigma. We show that semisimple Hopf algebras obtained as bicrossed products from an exact factorization of a finite group Si

S. V. Breimesser, James D. E. Grant, D. B. Pearson

We apply the methods of value distribution theory to the spectral asymptotics of Schrodinger operators with L^2-sparse potentials.

Y. Hu, A. S. Ustunel, M. Zakai

This paper deals with the study of the Malliavin calculus of Euclidean motions on Wiener space, (i.e. transformations induced by general measure preserving transformations, called `rotations&#39;, and H-valued shifts) and the associated flows on abstract Wiener spaces

A. M. Fedotov, N. B. Narozhny, V. D. Mur, V. A. Belinski

We propose a scalar background in Minkowski spacetime imparting constant proper acceleration to a classical particle. In contrast to the case of a constant electric field the proposed scalar potential does not create particle-antiparticle pairs. Therefore an elementary particle accelerated by such field is a more appropriate candidate for an &#34;Unruh-detec

Barak Kol

A straightforward generalization of the celebrated uniqueness theorem to dimensions greater than four was recently found to fail in two pure gravity cases - the 5d rotating black ring and the black string on R^{3,1} * S^1. Two amendments are suggested here (without proof) in order to rectify the situation. The first is that in addition to specifying the mass

K. S. Stelle

We review the relations between a family of domain-wall solutions to M-theory and gravitational instantons with special holonomy. When oxidized into the maximal-dimension parent supergravity, the transverse spaces of these domain walls become cohomogeneity-one spaces with generalized Heisenberg symmetries and a homothetic conformal symmetry. These metrics ma

Gerard &#39;t Hooft

Path integrals can be rigorously defined only in low dimensional systems where the small distance limit can be taken. Particularly non-trivial models in more than four dimensions can only be handled with considerable amount of speculation. In this lecture we try to put these various aspects in perspective.

J. Avan, H. M. Fried, Y. Gabellini

We present new, non trivial generalizations of the recent Tomaras, Tsamis and Woodard extension of the original Schwinger formula for charged pair production in a constant field.

Roberto Casadio, Laura Mersini

Current theoretical investigations seem to indicate the possibility of observing signatures of short distance physics in the Cosmic Microwave Background spectrum. We try to gain a deeper understanding on why all information about this regime is lost in the case of Black Hole radiation but not necessarily so in a cosmological setting by using the moving mirro