June 2002 arXiv papers — page 15

Andrew J. Berglund, Andrew C. Doherty, Hideo Mabuchi

We report high time-resolution measurements of photon statistics from pairs of dye molecules coupled by fluorescence resonance energy transfer (FRET). In addition to quantum-optical photon antibunching, we observe photon bunching on a timescale of several nanoseconds. We show by numerical simulation that configuration fluctuations in the coupled fluorophore

V. A. Ivanov, M. A. Smondyrev, J. T. Devreese

We consider the dependence of the MgB_2 superconducting critical temperature on the pressure. Our model exploits the influence of the large polarons on the band structure of the layered MgB_2 superconductor. Namely, the hole Pekar-Froehlich polarons form quasi two-dimensional potential wells in the boron plane which shift the positions of the sigma- and pi-b

Marek Cieplak, Trinh Xuan Hoang

We consider two types of Go models of a protein (crambin) and study their kinetics through molecular dynamics simulations. In the first model, the residue -- residue contact interactions are selected based on a cutoff distance, $R_c$, between the C$_α$ atoms. The folding times depend on the value of $R_c$ strongly and non-monotonically due to the interplay b

E. Akkermans, Ch. Miniatura, C. A. Müller

We present an analysis of the dephasing present in the multiple scattering of photons by atoms with a quantum internal structure. The corresponding phase coherence times $τ_ϕ$ are obtained as a function of the Zeeman degeneracy of the atomic dipole transition and the polarization state of the photons. These results allow for an explanation of the recent expe

T. Fukui

We study a Dirac fermion model with three kinds of disorder as well as a marginal interaction which forms the critical line of $c=1$ conformal field theory. Computing scaling equations by the use of a perturbative renormalization group method, we investigate how such an interaction affects the universality classes of disordered systems with non-interacting f

Ramin Golestanian, Tanniemola B. Liverpool

The effective elasticity of highly charged stiff polyelectrolytes is studied in the presence of counterions, with and without added salt. The rigid polymer conformations may become unstable due to an effective attraction induced by counterion density fluctuations. Instabilities at the longest, or intermediate length scales may signal collapse to globule, or

N. V. Surovtsev, A. P. Sokolov

Low-frequency Raman coupling coefficient of 11 different glasses is evaluated. It is found that the coupling coefficient demonstrates a universal linear frequency behavior near the boson peak maximum and a superlinear behavior at very low frequencies. The last observation suggests vanishing of the coupling coefficient when frequency tends to zero. The result

D. M. Cardamone, C. A. Stafford, B. R. Barrett

Coupled quantum dots are an example of the ubiquitous quantum double potential well. In a typical transport experiment, each quantum dot is also coupled to a continuum of states. Our approach takes this into account by using a Green's function formalism to solve the full system. The time-dependent solution is then explored in different limiting cases. In

T. Fang, H. L. Marshall, J. C. Lee, D. S. Davis

We report the first detection of an OVIII Ly-alpha absorption line associated with an overdense region in the intergalactic medium (IGM) along the sightline towards PKS 2155-304 with the Chandra Low Energy Transmission Grating Spectrometer (LETGS). The absorption line is detected at 4.5 sigma level with cz~16,600 km/s. At the same velocity Shull et al.(1998)

I. Rogachevskii, N. Kleeorin

The nonlinear coefficients defining the mean electromotive force (i.e., the nonlinear turbulent magnetic diffusion, the nonlinear effective velocity, the nonlinear kappa-tensor, etc.) are calculated for an anisotropic turbulence. A particular case of an anisotropic background turbulence (i.e., the turbulence with zero mean magnetic field) with one preferenti

H. C. Rosu, O. Cornejo, M. Reyes, D. Jimenez

Simple linear second-order differential equations have been written down for FRW cosmologies with barotropic fluids by Faraoni. His results have been extended by Rosu, who employed techniques belonging to nonrelativistic supersymmetry to obtain time-dependent adiabatic indices. Further extensions are presented here using the known connection between the line

Stephane Peigne

Within a perturbative scalar QED model recently considered by Brodsky et al., we study how leading-twist Coulomb rescatterings affect the Drell-Yan cross section at small x = x_{target}, and compare to the case of deep inelastic scattering at small x_{B}. We show that in the range where the transverse momentum transferred to the target is large compared to i

F. F. Assaad, V. Rousseau, F. Hebert, M. Feldbacher

We study spin and charge dynamics of stripes in doped Mott insulators by considering a two-dimensional Hubbard model with N fermion flavors. For N =2 we recover the normal one-band model while for N -> infty a spin density wave mean-field solution. For all band fillings, lattice topologies and N= 4 n the model may be solved by means of Monte Carlo methods wi

Kazuo Ghoroku, Masanobu Yahiro

We address the relation among the parameters of accelerating brane-universe embedded in five dimensional bulk space. It is pointed out that the tiny cosmological constant of our world can be obtained as quantum corrections around a given brane-solution in the bulk theory or in the field theory on the boundary from the holographic viewpoint.Some implications

Cyrus P. Master, Fumiko Yamaguchi, Yoshihisa Yamamoto

Quantum algorithms are well-suited to calculate estimates of the energy spectra for spin lattice systems. These algorithms are based on the efficient calculation of the discrete Fourier components of the density of states. The efficiency of these algorithms in calculating the free energy per spin of general spin lattices to bounded error is examined. We find

Jun Tsuzurugi, Masato Okada

We investigated the use of the Bayesian inference to restore noise-degraded images under conditions of spatially correlated noise. The generative statistical models used for the original image and the noise were assumed to obey multi-dimensional Gaussian distributions whose covariance matrices are translational invariant. We derived an exact description to b

JLQCD Collaboration, S. Aoki, M. Fukugita, S. Hashimoto

The calculation of the I=2 pion scattering length in quenched lattice QCD is revisited. The calculation is carried out with the Wilson fermion action employing Lüscher's finite size scaling method at $β=5.9$, 6.1, and 6.3 corresponding to the range of lattice spacing $a\simeq 0.12 - 0.07$ fm. We obtain in the continuum limit $a_0m_π= -0.0410(69)$, which

Holger Baumgardt, Piet Hut, Douglas C. Heggie

We report results of N-body simulations of isolated star clusters, performed up to the point where the clusters are nearly completely dissolved. Our main focus is on the post-collapse evolution of these clusters. We find that after core collapse, isolated clusters evolve along nearly a single sequence of models whose properties are independent of the initial

Erik van Nimwegen, Mihaela Zavolan, Nikolaus Rajewsky, Eric D. Siggia

Genome wide comparisons between enteric bacteria yield large sets of conserved putative regulatory sites on a gene by gene basis that need to be clustered into regulons. Using the assumption that regulatory sites can be represented as samples from weight matrices we derive a unique probability distribution for assignments of sites into clusters. Our algorith

Paul Seidel

This is an informal (and mostly conjectural) discussion of some aspects of Fukaya categories. We start by looking at exact symplectic manifolds which are obtained from a closed Calabi-Yau by removing a hyperplane section. We look at the possible geometric significance of Hochschild cohomology in this situation, and how one can try to get from the Fukaya cate

Daniel Krashen

A conjecture of Amitsur states that two Severi-Brauer varieties are birationally isomorphic if and only if the underlying algebras are the same degree and generate the same cyclic subgroup of the Brauer group. It is known that generating the same cyclic subgroup is a necessary condition, however it has not yet been shown to be sufficient. In this paper we ex

V. Bolotnikov, A. Kheifets, L. Rodman

A class is studied of complex valued functions defined on the unit disk (with a possible exception of a discrete set) with the property that all their Pick matrices have not more than a prescribed number of negative eigenvalues. Functions in this class, known to appear as pseudomultipliers of the Hardy space, are characterized in several other ways. It turns

Peter Ebenfelt, Xiaojun Huang, Dmitri Zaitsev

We consider local CR-immersions of a strictly pseudoconvex real hypersurface $M\subset\bC^{n+1}$, near a point $p\in M$, into the unit sphere $\mathbb S\subset\bC^{n+d+1}$ with $d>0$. Our main result is that if there is such an immersion $f\colon (M,p)\to \mathbb S$ and $d < n/2$, then $f$ is {\em rigid} in the sense that any other immersion of $(M,p)$ into

E. S. Key, M. Klosek, D. Abbott

We construct games of chance from simpler games of chance. We show that it may happen that the simpler games of chance are fair or unfavourable to a player andyet the new combined game is favourable -- this is a counter-intuitive phenomenoknown as Parrondo&#39;s paradox. We observe that all of the games in question are random walks in periodic environments (

R. Pyke

In a series of papers, G. Harmer and D. Abbott study the behavior of random walks associated with games introduced in 1997 by J. M. R. Parrondo. These games illustrate an apparent paradox that random and deterministic mixtures of losing games may produce winning games. In this paper, classical cyclic random walks on the additive group of integers modulo $m$,

Fiammetta Battaglia, Elisa Prato

In this research announcement we associate to each convex polytope, possibly nonrational and nonsimple, a family of compact spaces that are stratified by quasifolds, i.e. the strata are locally modelled by $\R^k$ modulo the action of a discrete, possibly infinite, group. Each stratified space is endowed with a symplectic structure and a moment mapping having

H. Casini, R. Montemayor, Luis F. Urrutia

A generalization of duality transformations for arbitrary Lorentz tensors is presented, and a systematic scheme for constructing the dual descriptions is developed. The method, a purely Lagrangian approach, is based on a first order parent Lagrangian, from which the dual partners are generated. In particular, a family of theories which are dual to the massiv

Wolfgang A. Rolke, Angel M. Lopez

We discuss a method for correcting the bias in the limits for small signals if those limits were found based on cuts that were chosen by minimizing a criterion such as sensitivity. Such a bias is commonly present when a &#34;minimization&#34; and an &#34;evaluation&#34; are done at the same time. We propose to use a variant of the bootstrap to adjust the lim

A. E. Dorokhov

The behaviour of the pion transition form factor for the process $γ^\starγ\to π^0$ and $γ^\starγ^\star\to π^0$ at space-like values of photon momenta is estimated within the nonlocal covariant quark-meson model. The nonlocal contributions are important to install the axial anomaly at zero photon virtualities and give the contributions to the twist-4 power co

Denis V. Popel, Anita Dani

This paper introduces a new approach to represent logic functions in the form of Sierpinski Gaskets. The structure of the gasket allows to manipulate with the corresponding logic expression using recursive essence of fractals. Thus, the Sierpinski gasket&#39;s pattern has myriad useful properties which can enhance practical features of other graphic represen

Bart Goethals, Jan Van den Bussche

In recent years, the problem of association rule mining in transactional data has been well studied. We propose to extend the discovery of classical association rules to the discovery of association rules of conjunctive queries in arbitrary relational data, inspired by the WARMR algorithm, developed by Dehaspe and Toivonen, that discovers association rules o

A. N. Bogdanov, U. K. Roessler, M. Wolf, K. -H. Muller

A phenomenological theory of magnetic states in noncentrosymmetric tetragonal antiferromagnets is developed, which has to include homogeneous and inhomogeneous terms (Lifshitz-invariants) derived from Dzyaloshinskii-Moriya couplings. Magnetic properties of this class of antiferromagnets with low crystal symmetry are discussed in relation to its first known m

V. A. Kuprievich, O. L. Kapitanchuk, O. V. Shramko

The calculations of the charge distribution in C$_{60}$-based FET structure are presented. A simple model is proposed to describe the distribution of the injected electrons or holes between two-dimensional layers. The calculations show that the relative charge distribution between the layers turns to be independent on the total amount of injected charges. Th

P. Gegenwart, J. Custers, C. Geibel, K. Neumaier

We report low-temperature calorimetric, magnetic and resistivity measurements on the antiferromagnetic (AF) heavy-fermion metal YbRh$_2$Si$_2$ (${T_N =}$ 70 mK) as a function of magnetic field $B$. While for fields exceeding the critical value ${B_{c0}}$ at which ${T_N\to0}$ the low temperature resistivity shows an ${AT^2}$ dependence, a ${1/(B-B_{c0})}$ div

F. Anfuso, E. Ercolessi, G. Morandi, M. Roncaglia

We analyze the gaps in the excitation spectrum of a Haldane chain with single-ion anisotropy in a staggered field. We show that the gap along the direction of the field increases at a faster rate than the others, while its spectral weight decreases, being transferred to a two-magnon continuum.

Gwang-Hee Kim, Mincheol Shin

Quantum vortex tunneling is studied for the case where the Hall and the dissipative dynamics are simultaneously present. For a given temperature, the magnetization relaxation rate is calculated as a function of the external current and the quasiparticle scattering time. The relaxation rate is solved analytically at zero temperature and obtained numerically a

Jung Hoon Han

We consider the influence of magnetic excitations on the local density of states in the d-wave superconductor. The magnetic susceptibility is calculated within the renormalized $t-t&#39;-J$ model and its influence on the quasiparticle self-energy is considered using a minimal model originally proposed by Polkovnikov {\it et al.}[cond-mat/0203176]. We find th

Robert A. Pelcovits, Robert B. Meyer

In a nematic gel, the appearance of nematic order is accompanied by a spontaneous elongation of the gel parallel to the nematic director. If such a gel is made chiral, it has a tendency to form a cholesteric helical texture, in which local elongation of the gel parallel to the nematic director is suppressed due to the requirement of elastic compatibility. We

Marc J. Kuchner, Michael E. Brown, Matthew Holman

We numerically integrated the orbits of 1458 particles in the region of the classical Kuiper Belt (41 AU < a < 47 AU) to explore the role of dynamical instabilities in sculpting the inclination distribution of the classical Kuiper Belt Objects (KBOs). We find that the selective removal of low-inclination objects by overlapping secular resonances (nu_17 and n

G. Iovane

MEDEA is a software architecture to detect luminosity variations connected with the discovery of new planet outside the Solar System. Taking into account the enormous number of stars to monitor for our aim traditional approaches are very demanding in terms of computing time; here, the implementation of an automatic vision and decision system, which allows to

P. A. Crowther, D. J. Hillier, C. J. Evans, A. W. Fullerton

We have undertaken quantitative analysis of four LMC and SMC O4--9.7 extreme supergiants using far-ultraviolet FUSE, ultraviolet IUE/HSTand optical VLT UVES spectroscopy. Extended, non-LTE model atmospheres that allow for the consistent treatment of line blanketing are used to analyse wind & photospheric spectral features simultaneously. Using Halpha to cons

Michael J. Harris

I argue that the existence of cold antimatter in bulk is not permitted by the Standard Model, so that if a gamma-ray signature from antiproton annihilation were to be detected, it must represent either new physics or the action of intelligence. Time variability of the signal would strongly support the second alternative. The entire sky was scanned at the rel

Will J. Percival, Will Sutherland, John A. Peacock, Carlton M. Baugh

We constrain flat cosmological models with a joint likelihood analysis of a new compilation of data from the cosmic microwave background (CMB) and from the 2dF Galaxy Redshift Survey (2dFGRS). Fitting the CMB alone yields a known degeneracy between the Hubble constant h and the matter density Omega_m, which arises mainly from preserving the location of the p

H. Nunokawa, W. J. C. Teves, R. Zukanovich Funchal

Assuming that neutrinos are Majorana particles, in a three generation framework, current and future neutrino oscillation experiments can determine six out of the nine parameters which fully describe the structure of the neutrino mass matrix. We try to clarify the interplay among the remaining parameters, the absolute neutrino mass scale and two CP violating

Ronald Dickman, Francisco Fontenele Araujo,, Daniel ben-Avraham

We study an unbiased, discrete time random walk on the nonnegative integers, with the origin absorbing. The process has a history-dependent step length: the walker takes steps of length v while in a region which has been visited before, and steps of length n when entering a region that has never been visited. The process provides a simplified model of spread

Pankaj S. Joshi, Rituparno Goswami

We bring out here the role of initial data in causing the black hole and naked singularity phases as the final end state of a continual gravitational collapse. The collapse of a type I general matter field is considered, which includes most of the known physical forms of matter. It is shown that given the distribution of the density and pressure profiles at

Heather E. Logan, Shufang Su

We study the loop-induced process e+e- --> W+H- in the Minimal Supersymmetric Standard Model (MSSM). This process allows the charged Higgs boson to be produced in e+e- collisions when its mass is larger than half the center-of-mass energy, so that e+e- --> H+H- is kinematically forbidden. By scanning over the MSSM parameters subject to experimental constrain

Kimberly C. B. New

Gravitational wave emission from the gravitational collapse of massive stars has been studied for more than three decades. Current state of the art numerical investigations of collapse include those that use progenitors with realistic angular momentum profiles, properly treat microphysics issues, account for general relativity, and examine non--axisymmetric

Rafal Ciesielski, Zygmunt Lalak

We have investigated moduli stabilization leading to hierarchical supersymmetry breakdown in racetrack models with two moduli fields simultaneously present in the effective racetrack superpotential. We have shown that stabilization of moduli occurs when a shift symmetry of the moduli space becomes gauged. This gauging results in a D-term contribution to the

B. P. Crill, P. A. R. Ade, D. R. Artusa, R. S. Bhatia

We describe BOOMERANG; a balloon-borne microwave telescope designed to map the Cosmic Microwave Background (CMB) at a resolution of 10&#39; from the Long Duration Balloon (LDB) platform. The millimeter-wave receiver employs new technology in bolometers, readout electronics, cold re-imaging optics, millimeter-wave filters, and cryogenics to obtain high sensit

L. Trache, F. Carstoiu, A. M. Mukhamedzhanov, R. E. Tribble

We have used existing data on the one-proton-removal cross section of 9C at 285 MeV/u and Glauber model calculations to extract the asymptotic normalization coefficient for the wave function of the last proton in the ground state of 9C. The calculations are done first using folded potentials starting from two different effective nucleon-nucleon interactions

Filipe Moura

We fully compute the N=1 supersymmetrization of the fourth power of the Weyl tensor in d=4 x-space with the auxiliary fields. In a previous paper, we showed that their elimination requires an infinite number of terms; we explicitely compute those terms to order κ^4 (three loop). We also write, in superspace notation, all the possible N=1 actions, in four dim

D. R. Gies, C. T. Bolton, J. R. Thomson, W. Huang

We present the results of a spectroscopic monitoring program (from 1998 to 2002) of the H-alpha emission strength in HDE 226868, the optical counterpart of the black hole binary, Cyg X-1. The H-alpha profiles consist of (1) a P Cygni component associated with the wind of the supergiant, (2) emission components that attain high velocity at the conjunctions an

P. O. Bowman, U. M. Heller, D. B. Leinweber, A. G. Williams

The Laplacian gauge is a nonperturbative gauge fixing that reduces to Landau gauge in the asymptotic limit. Like Landau gauge, it respects Lorentz invariance, but it is free of Gribov copies; the gauge fixing is unambiguous. In this paper we study the infrared behavior of the lattice gluon propagator in Laplacian gauge by using a variety of lattices with spa

M. Eschrig, J. Kopu, J. C. Cuevas, Gerd Schön

We investigate the coupling between two singlet superconductors separated by a half-metallic magnet. The mechanism behind the coupling is provided by the rotation of the quasiparticle spin in the superconductor during reflection events at the interface with the half metal. Spin rotation induces triplet correlations in the superconductor which, in the presenc

M. Wing

A much improved determination of the transverse energy of jets has been carried out in ZEUS, using a correction procedure based on two independent methods. The first is based on a combination of tracking and calorimeter information which optimises the resolution of reconstructed kinematic variables. The conservation of energy and momentum in neutral current

D. I. Golosov

We investigate the structure of magnetic domain walls in a classical double exchange ferromagnet, evaluating domain wall energies and charges. Three different cases are studied: (i) a conventional smooth Bloch wall, (ii) an abrupt Ising-type wall, which is shown to have lower energy at small values of carrier concentration, and (iii) stripe wall, correspondi

N. Lehner

We discuss FUSE observations of two early-type stars, DI1388 and DGIK975, in the low density and low metallicity gas of Magellanic Bridge (MB). Toward DI1388, the FUSE observations show molecular hydrogen, O VI, and numerous other atomic or ionic transitions in absorption, implying the presence of multiple gas phases in a complex arrangement. The relative ab

Annalisa Fierro, Mario Nicodemi, Antonio Coniglio

We discuss a Statistical Mechanics approach in the manner of Edwards to the ``inherent states&#39;&#39; (defined as the stable configurations in the potential energy landscape) of glassy systems and granular materials. We show that at stationarity the inherent states are distributed according a generalized Gibbs measure obtained assuming the validity of the

Hans Jörg Limbach, Christian Holm, Kurt Kremer

We present simulations on charged polymers in poor solvent. First we investigate in detail the dilute concentration range with and without imposed extension constraints. The resulting necklace polymer conformations are analyzed in detail. We find strong fluctuations in the number of pearls and their sizes leading only to small signatures in the form factor a

V. Bozza, M. Gasperini, M. Giovannini, G. Veneziano

We present the results of a detailed study of how isocurvature axion fluctuations are converted into adiabatic metric perturbations through axion decay, and discuss the constraints on the parameters of pre-big bang cosmology needed for consistency with present CMB-anisotropy data. The large-scale normalization of temperature fluctuations has a non-trivial de

Masahito Hayashi, Masato Koashi, Keiji Matsumoto, Fumiaki Morikoshi

Consider entanglement concentration schemes that convert n identical copies of a pure state into a maximally entangled state of a desired size with success probability being close to one in the asymptotic limit. We give the distillable entanglement, the number of Bell pairs distilled per copy, as a function of an error exponent, which represents the rate of

D. Giuliano, P. Sodano, A. Tagliacozzo

A Berry phase can be added to the wavefunction of an isolated quantum dot by adiabatically modulating a nonuniform electric field along a time-cycle. The dot is tuned close to a three-level degeneracy, which provides a wide range of possibilities of control. We propose to detect the accumulated phase by capacitively coupling the dot to a double-path intefero

James F. Lutsko

The effect of velocity correlations on the equal-time density autocorrelation function, e.g. the pair distribution function or pdf, of a hard-sphere fluid undergoing shear flow is investigated. The pdf at contact is calculated within the Enskog approximation and is shown to be in good agreement with molecular dynamics simulations for shear rates below the sh

S. Rai Choudhury, Naveen Gaur

In this paper we study the polarization asymmetries of the final state lepton in the radiative dileptonic decay of B meson (\bsllg) in the framework of Minimal Supersymmetric Standard Model (MSSM) and various other unified models within the framework of MSSM e.g. mSUGRA, SUGRA (where condition of universality of scalar masses is relaxed) etc. Lepton polariza

A. D. Drozdov, J. deC. Christiansen, R. K. Gupta, A. P. Shah

Experimental data are reported on moisture diffusion and the elastoplastic response of an intercalated nanocomposite with vinyl ester resin matrix and montmorillonite clay filler at room temperature. Observations in diffusion tests show that water transport in the neat resin is Fickian, whereas it becomes anomalous (non-Fickian) with the growth of the clay c

Takeru Ken Suzuki

We investigate possibilities of solar coronal heating by acoustic waves generated not at the photosphere but in the corona, aiming at heating in the mid- to low-latitude corona where the low-speed wind is expected to come from. Acoustic waves of period tau ~ 100s are triggered by chromospheric reconnection, one model of small scale magnetic reconnection even

Miguel H. Ibanez S., Yuri A. Shchekinov

The dynamics of linear perturbations in a radiatively cooling dusty plasma is considered, with the charge of both dust ($Z_d$) and plasma ($Z_p$) components being allowed to vary with their densities. It is shown that in the long-wavelength limit corresponding to the characteristic cooling length, when the plasma can be treated as quasineutral, the presence

Ragnvald J. Irgens, Per B. Lilje, Haakon Dahle, S. J. Maddox

Dynamic velocity dispersion and mass estimates are given for a sample of five X-ray luminous rich clusters of galaxies at intermediate redshifts (z~0.3) drawn from a sample of 39 clusters for which we have obtained gravitational lens mass estimates. The velocity dispersions are determined from between 9 and 20 redshifts measured with the LDSS spectrograph of

U. F. Keyser, C. Fuhner, S. Borck, R. J. Haug

A small quantum ring with less than 10 electrons was studied by transport spectroscopy. For strong coupling to the leads a Kondo effect is observed and used to characterize the spin structure of the system in a wide range of magnetic fields. At small magnetic fields Aharonov-Bohm oscillations influenced by Coulomb interaction appear. They exhibit phase jumps

D. Davesne, M. Oertel, H. Hansen

In this paper, we develop a consistent extension of RPA for bosonic systems. In order to illustrate the method, we consider the case of the anharmonic oscillator. We compare our results with those obtained in mean-field and standard RPA approaches, with the exact ones and show that they are very close to the exact ones.

G. Picard, A. Ajdari, L. Bocquet, F. Lequeux

Various experiments evidence spatial heterogeneities in sheared yield stress fluids. To account for heterogeneities in the velocity gradient direction, we use a simple model corresponding to a non-monotonous local constitutive curve and study a simple shear geometry. Different types of boundary conditions are considered. Under controlled macroscopic shear st

H. Itoyama, T. Oota

We consider the model in two dimensions with boundary quadratic deformation (BQD), which has been discussed in tachyon condensation. The partition function of this model (BQD) on a cylinder is determined, using the method of zeta function regularization. We show that, for closed channel partition function, a subtraction procedure must be introduced in order

A. Rakhimov, Jae Hyung Yee

We have extended the variational perturbative theory based on the back ground field method to include the optimized expansion of Okopinska and the post Gaussian effective potential of Stansu and Stevenson. This new method provides much simpler way to compute the correction terms to the Gausssian effective action (or potential). We have also renormalized the

Yonina C. Eldar

In this paper we consider the problem of unambiguous discrimination between a set of linearly independent pure quantum states. We show that the design of the optimal measurement that minimizes the probability of an inconclusive result can be formulated as a semidefinite programming problem. Based on this formulation, we develop a set of necessary and suffici

S. V. Zharikov, Yu. A. Shibanov, A. B. Koptsevich, N. Kawai

We report the B band optical observations of an old (17.5 Myr) radiopulsar PSR B0950+08 obtained with the Suprime-Cam at the Subaru telescope. We detected a faint object, B=27.07(16). Within our astrometrical accuracy it coincides with the radio position of the pulsar and with the object detected earlier by Pavlov et al. (1996) in UV with the HST/FOC/F130LP.

N. Laskin

Properties of the fractional Schrodinger equation have been studied. We have proven the hermiticity of fractional Hamilton operator and established the parity conservation law for the fractional quantum mechanics. As physical applications of the fractional Schrodinger equation we have found the energy spectrum for a hydrogen-like atom - fractional &#39;&#39;

K. Eckert, J. Mompart, X. X. Yi, J. Schliemann

We investigate quantum computation with neutral atoms in optical microtraps where the qubit is implemented in the motional states of the atoms, i.e., in the two lowest vibrational states of each trap. The quantum gate operation is performed by adiabatically approaching two traps and allowing tunneling and cold collisions to take place. We demonstrate the cap

G. N. Ord, R. B. Mann

We show that a point particle moving in space-time on entwined-pair paths generates Schroedinger&#39;s equation in a static potential in the appropriate continuum linit. This provides a new realist context for the Schroedinger equation within the domain of classical stochastic processes. It also suggests that self-quantizing systems may provide considerable

JM Geremia, Jon Williams, Hideo Mabuchi

Photonic band gap (PBG) materials are attractive for cavity QED experiments because they provide extremely small mode volumes and are monolithic, integratable structures. As such, PBG cavities are a promising alternative to Fabry-Perot resonators. However, the cavity requirements imposed by QED experiments, such as the need for high Q (low cavity damping) an

Richard J. Hughes, Jane E. Nordholt, Derek Derkacs, Charles G. Peterson

We have demonstrated quantum key distribution (QKD) over a 10-km, 1-airmass atmospheric range during daylight and at night. Secret random bit sequences of the quality required for the cryptographic keys used to initialize secure communications devices were transferred at practical rates with realistic security. By identifying the physical parameters that det

Mary Beth Ruskai

Recently a method for adiabatic quantum computation has been proposed and there has been considerable speculation about its efficiency for NP-complete problems. Heuristic arguments in its favor are based on the unproven assumption of an eigenvalue gap. We show that, even without the assumption of an eigenvalue gap, other standard arguments can be used to sho

Y. Nosochkov, P. Raimondi, T. O. Raubenheimer, A. Seryi

Realistic calculation of NLC luminosity has been performed using particle tracking in DIMAD and beam-beam simulations in GUINEA-PIG code for various values of beam emittance, energy and beta functions at the Interaction Point (IP). Results of the simulations are compared with analytic luminosity calculations. The optimum range of IP beta functions for high l

I. G. Aznauryan

Two approaches for analysis of pion photo- and electroproduction on nucleons in the resonance energy region are checked at $Q^2=0$ using the results of GWU(VPI) partial-wave analysis of photoproduction data. The approaches are based on dispersion relations and unitary isobar model. Within dispersion relations good description of photoproduction multipoles is

David R Harrington

Dispersive corrections to the total cross section for high-energy scattering from a heavy nucleus are calculated using a matrix model, based on the triple-Pomeron behavior of diffractive scattering from a single nucleon, for the cross section operator connecting different states of the projectile nucleon . Energy-dependent effects due to the decrease in long

Peter A. Braun, Stefan Heusler, Sebastian Müller, Fritz Haake

Employing symbolic dynamics for geodesic motion on the tesselated pseudosphere, the so-called Hadamard-Gutzwiller model, we construct extremely long periodic orbits without compromising accuracy. We establish criteria for such long orbits to behave ergodically and to yield reliable statistics for self-crossings and avoided crossings. Self-encounters of perio

Barry Simon, Andrej Zlatos

We study the Case sum rules, especially $C_0$, for general Jacobi matrices. We establish situations where the sum rule is valid. Applications include an extension of Shohat&#39;s theorem to cases with an infinite point spectrum and a proof that if $\lim n (a_n -1)=α$ and $\lim nb_n =β$ exist and $2α<\absβ$, then the Szegő condition fails.

Peter Gilkey, Klaus Kirsten

We study the heat content asymptotics on a Riemannian manifold with smoooth boundary defined by Dirichlet, Neumann, transmittal and transmission boundary conditions.

P P Martin, A Elgamal

We introduce the ramified partition algebra, which is a physically motivated and natural generalization of the partition algebra. We investigate its representation theory and demonstrate quasi--heredity under certain conditions. Under these conditions we determine an index set for simple modules and construct standard modules with this index set. We construc

Sophie Térouanne

In this note we consider a quotient π: X-> X/G, with G a finite group and X a smooth projective scheme such that X/G is smooth. We compare the equivariant derived category D^G(X) and the derived category of the quotient D(X/G) by giving the image of the functor π^*: D(X/G)-> D^G(X).

Bert van Es, Peter Spreij, Harry van Zanten

We consider discrete time models for asset prices with a stationary volatility process. We aim at estimating the multivariate density of this process at a set of consecutive time instants. A Fourier type deconvolution kernel density estimator based on the logarithm of the squared process is proposed to estimate the volatility density. Expansions of the bias

Alexander I. Bobenko, Tatyana V. Pavlyukevich, Boris A. Springborn

We present a global representation for surfaces in 3-dimensional hyperbolic space with constant mean curvature 1 (CMC-1 surfaces) in terms of holomorphic spinors. This is a modification of Bryant&#39;s representation. It is used to derive explicit formulas in hypergeometric functions for CMC-1 surfaces of genus 0 with three regular ends which are asymptotic

Thibault Damour, Sophie de Buyl, Marc Henneaux, Christiane Schomblond

In recent papers, it has been shown that (i) the dynamics of theories involving gravity can be described, in the vicinity of a spacelike singularity, as a billiard motion in a region of hyperbolic space bounded by hyperplanes; and (ii) that the relevant billiard has remarkable symmetry properties in the case of pure gravity in $d+1$ spacetime dimensions, or

Lorenzo Leal

We study a generalization of the group of loops based on sets of signed points, instead of paths or loops. This geometrical setting incorporates the kinematical constraints of the Sigma Model, inasmuch as the the group of loops does with the Bianchi identities of Yang-Mills theories. We employ an Abelian version of this construction to quantize the Self-Dual

K. Shima, M. Tsuda

We show explicitly by the heuristic and practical arguments that for $N = 2$ supersymmetry (SUSY) a SUSY invariant relation between component fields of a vector supermultiplet of linear SUSY and Nambu-Goldstone fermions of the Volkov-Akulov model of nonlinear SUSY is written by using only three arbitrary dimensionless parameters, which can be recasted as the

F. J. Botella, G. C. Branco, M. Nebot, M. N. Rebelo

Assuming that the Kobayashi-Maskawa mechanism gives the dominant contribution to CP violation at low energies, we propose a novel way of testing the flavour sector of the Standard Model which has the potencial for discovering New Physics. Using 3 x 3 unitarity of the V_{CKM} matrix and choosing a complete set of rephasing invariant phases, we derive a set of

B. C. Tiburzi

We present generalized parton distributions for weakly bound systems on the light cone in order to build intuition about the light-front formalism. Physics at the crossover is reviewed in terms of the light-cone Fock space representation. Furthermore, we link light-cone Fock components to the equal (light-cone) time projection of the covariant Bethe-Salpeter

N. Timneanu, J. Kwiecinski, L. Motyka

We introduce a saturation model for photon-photon interactions, based on a QCD dipole picture of high energy scattering. The two-dipole cross-section is assumed to satisfy the saturation property. This pomeron-like contribution is supplemented with QPM and non-pomeron reggeon contributions. The model gives a very good description of the data on the gamma-gam

J. Kwiecinski, L. Motyka, N. Timneanu

A saturation model for the total gamma-gamma and gamma*-gamma* cross-sections and for the real photon structure function F_2^gamma(x,Q^2) is described. The model is based on a QCD dipole picture of high energy scattering. The two-dipole cross-section is assumed to satisfy the saturation property with the saturation radius taken from the GBW analysis of the g

P. Lach, P. Zenczykowski

We discuss all contributions from Zweig-rule-satisfying SU(3)-symmetric inelastic FSI-induced corrections in B decays to $ππ$, $πK$, $K\bar{K}$, $πη(η&#39;)$, and $K η(η&#39;)$ . It is shown how all of these FSI corrections lead to a simple redefinition of the amplitudes, permitting the use of a simple diagram-based description, in which, however, weak phase