February 2003 arXiv papers — page 11

Stoytcho S. Yazadjiev

We present new analytical self-similar solutions describing a collapse of a massless scalar field in scalar-tensor theories. The solutions exhibit a type of critical behavior. The black hole mass for the near critical evolution is analytically obtained for several scalar-tensor theories and the critical exponent is calculated. Within the framework of the ana

S. Willenbrock

Gauge-coupling unification is just as successful in the standard model with six Higgs doublets as it is in the minimal supersymmetric standard model. However, the gauge couplings unify at 10^14 GeV, which yields rapid proton decay in the SU(5) model. I propose that the grand-unified gauge group is instead SU(3)_c x SU(3)_L x SU(3)_R, in which baryon number i

P. Butera, M. Comi, A. J. Guttmann

For the study of Ising models of general spin S on the square lattice, we have combined our recently extended high-temperature expansions with the low-temperature expansions derived some time ago by Enting, Guttmann and Jensen. We have computed for the first time various critical parameters and improved the estimates of others. Moreover the properties of hyp

M. R. James

The importance of feedback control is being increasingly appreciated in quantum physics and applications. This paper describes the use of optimal control methods in the design of quantum feedback control systems, and in particular the paper formulates and solves a risk-sensitive optimal control problem. The resulting risk-sensitive optimal control is given i

H. Fujii

Soft mode near the critical end point in the phase diagram of two-flavor Nambu--Jona-Lasinio (NJL) model is investigated within the leading 1/N_c approximation with N_c being the number of the colors. It is explicitly shown by studying the spectral function of the scalar channel that the relevant soft mode is the scalar density fluctuation, which is coupled

A. Doff, A. A. Natale

We argue that the masses of the first and third fermionic generations, which are respectively of the order of a few MeV up to a hundred GeV, are originated in a dynamical symmetry breaking mechanism leading to masses of the order $αμ$, where $α$ is a small coupling constant and $μ$, in the case of the first fermionic generation, is the scale of the dynamical

R. Dodson, D. Legge, J. E. Reynolds, P. M. McCulloch

The Vela pulsar is the brightest pulsar at radio wavelengths. It was the object that told us (via its glitching) that pulsars were solid rotating bodies not oscillating ones. Along with the Crab pulsar is it the source of many of the models of pulsar behavior. Therefore it is of vital importance to know how far away it is, and its origin. The proper motion a

R. Dodson, D. Lewis, D. McConnell, A. A. Deshpande

We have discovered that the radio nebula surrounding the Vela pulsar covers a much wider extent than previously reported, with two lobes to the North and South of the pulsar. Indications of this object have been reported previously, but its symmetric morphology around the pulsar and other details had not been identified as they were hidden due to poor sensit

T. Bastin, E. Solano

We study the population trapping phenomenon for the one-photon mazer. With this intent, the mazer theory is written using the dressed-state coordinate formalism, simplifying the expressions for the atomic populations, the cavity photon statistics, and the reflection and transmission probabilities. Under the population trapping condition, evidence for new pro

Artur Lozinski, Andreas Buchleitner, Karol Zyczkowski, Thomas Wellens

We derive an analytical expression for the lower bound of the concurrence of mixed quantum states of composite 2xK systems. In contrast to other, implicitly defined entanglement measures, the numerical evaluation of our bound is straightforward. We explicitly evaluate its tightness for general mixed states of 2x3 systems, and identify a large class of states

J. Batle, M. Casas, A. Plastino, A. R. Plastino

In the present study we revisit the application of the $q$-information measures $R_q$ of Rényi's and $S_q$ of Tsallis' to the discussion of special features of two qubits systems. More specifically, we study the correlations between the $q$-information measures and the entanglement of formation of a general (pure or mixed) state $ρ$ describing a syst

V. Josse, A. Dantan, A. Bramati, M. Pinard

We present a theoretical study of an ensemble of X-like 4-level atoms placed in an optical cavity driven by a linearly polarized field. We show that the self-rotation (SR) process leads to polarization switching (PS). Below the PS threshold, both the mean field mode and the orthogonal vacuum mode are squeezed. We provide a simple analysis of the phenomena re

Zafar Ahmed

We propose construction of a unique and definite metric ($η_+$), time-reversal operator (T) and an inner product such that the pseudo-Hermitian matrix Hamiltonians are C, PT, and CPT invariant and PT(CPT)-norm is indefinite (definite). Here, P and C denote the generalized symmetries : parity and charge-conjugation respectively. The limitations of the other c

Dagomir Kaszlikowski, L. C. Kwek, Marek Zukowski, Berthold-Georg Englert

We propose entropic measures for the strength of single-particle and two-particle interference in interferometric experiments where each particle of a pair traverses a multi-path interferometer. Optimal single-particle interference excludes any two-particle interference, and vice versa. We report an inequality that states the compromises allowed by quantum m

Michal Horodecki, Pawel Horodecki, Jonathan Oppenheim

Quantum compression can be thought of not only as compression of a signal, but also as a form of cooling. In this view, one is interested not in the signal, but in obtaining purity. In compound systems, one may be interested to cool the system to obtain {\it local purity} by use of local operations and classical communication [Oppenheim et al. Phys. Rev. Let

J. Roland, N. J. Cerf

We analyze three different quantum search algorithms, the traditional Grover's algorithm, its continuous-time analogue by Hamiltonian evolution, and finally the quantum search by local adiabatic evolution. We show that they are closely related algorithms in the sense that they all perform a rotation, at a constant angular velocity, from a uniform superpo

Rob Clifton, Jeffrey Bub, Hans Halvorson

We show that three fundamental information-theoretic constraints--the impossibility of superluminal information transfer between two physical systems by performing measurements on one of them, the impossibility of broadcasting the information contained in an unknown physical state, and the impossibility of unconditionally secure bit commitment--suffice to en

D. L. Khokhlov

It is considered the detection of neutrinos moving from the opposite directions. The states of the particle of the detector interacting with the neutrinos are connected with the P-transformation. Hence only a half of neutrinos gives contribution into the superposition of the neutrino states. Taking into account the effect of the opposite neutrino directions

Gonzalo E. Reyes, Antoine Royer

Newton's law of motion relative to an inertial frame ("the laboratory") for a particle subject to a force acting at a certain time may be interpreted in either of two ways: (1) The force acting on the particle during an infinitesimal time imparts to the laboratory a boost (impulse divided by the mass) while the particle maintains the original vel

V. P. Ruban

Hamiltonian dynamics of a thin vortex filament in ideal incompressible fluid near a flat fixed boundary is considered at the conditions that at any point of the curve determining shape of the filament the angle between tangent vector and the boundary plane is small, also the distance from a point on the curve to the plane is small in comparison with the curv

John Gilman

The phenomenon of ball lightning has been observed for a long time, but the nature of these luminous balls has been unknown. It is proposed here that they consist of highy excited Rydberg atoms with large polarizabilities that bind them together. Thus the cohesion of the balls comes from photon exchange forces (London dispersion forces) rather than the more

A. Hildebrandt, O. Kohlbacher, R. Blossey, H. -P. Lenhof

Solvation free energy is an important quantity in Computational Chemistry with a variety of applications, especially in drug discovery and design. The accurate prediction of solvation free energies of small molecules in water is still a largely unsolved problem, which is mainly due to the complex nature of the water-solute interactions. In this letter we dev

Michael Ibison

Attempts at an electromagnetic explanation of the inertial mass of charged particles have recently been revived within the framework of Stochastic Electrodynamics, characterized by the adoption of a classical version of the electromagnetic zero-point field (ZPF). Recent claims of progress in that area have to some extent received support from related claims

T. Barnes, E. S. Swanson, C. -Y. Wong, X. -M. Xu

We present numerical results for the dissociation cross sections of ground-state, orbitally- and radially-excited charmonia in collisions with light mesons. Our results are derived using the nonrelativistic quark model, so all parameters are determined by fits to the experimental meson spectrum. Examples of dissociation into both exclusive and inclusive fina

A. Fix, H. Arenhoevel

The optical potential approach for low-energy scattering of $η$-mesons on three-body nuclei is compared to an exact treatment of the $η3N$ system using four-body scattering theory with separable interactions in s-waves only. The higher-order terms including the interaction of the struck nucleon with the surrounding nuclear medium and virtual target excitatio

M. J. Ramsey-Musolf

I discuss several physics issues that can be addressed through the present and future program of parity-violating electron scattering measurements. In particular, I focus on strange quark form factors, hadronic effects in electroweak radiative corrections, and physics beyond the Standard Model.

R. Arnold, C. Augier, J. Baker, A. Barabash

The background induced by radioactive impurities of $^{208}\rm Tl$ and $^{214}\rm Bi$ in the source of the double beta experiment NEMO-3 has been investigated. New methods of data analysis which decrease the background from the above mentioned contamination are identified. The techniques can also be applied to other double beta decay experiments capable of m

T. Bartsch, J. Main, G. Wunner

Semiclassical periodic-orbit theory and closed-orbit theory represent a quantum spectrum as a superposition of contributions from individual classical orbits. Close to a bifurcation, these contributions diverge and have to be replaced with a uniform approximation. Its construction requires a normal form that provides a local description of the bifurcation sc

M. Wendeker, G. Litak, J. Czarnigowski, K. Szabelski

We report our results on non-periodic experimental time series of pressure in a spark ignition engine. The experiments were performed for a low rotational velocity of a crankshaft and a relatively large spark advance angle. We show that the combustion process has many chaotic features. Surprisingly, the reconstructed attractor has a characteristic butterfly

Mark A. Taylor, Susan Kurien, Gregory L. Eyink

One of the main benchmarks in direct numerical simulations of three-dimensional turbulence is the Kolmogorov 1941 prediction for third-order structure functions with homogeneous and isotropic statistics in the infinite-Reynolds number limit. Previous DNS techniques to obtain isotropic statistics have relied on time-averaging structure functions in a few dire

Eugene Perchik

J. Hadamard's ideas of correct formulation of problems of mathematical physics as well as related Banach's theorem on the inverse operator are analyzed. Modern techniques of numerical simulations are shown to be in drastic contradiction to the concepts of J. Hadamard, S. Banach and a number of other outstanding scientists in the sense that the priori

N. G. Marchuk

We prove the following theorem: the Dirac equation for an electron (invented by P.A.M.Dirac in 1928) can be written as a tensor equation. An equation is called a tensor equation if all values in it are tensors and all operations in it take tensors to tensors.

Ken Ito

We investigate in detail relationships between the set ${\mathfrak B}^\infty$ of all infinite ``biconvex'' sets in the positive root system $Δ_+$ of an arbitrary untwisted affine Lie algebra ${\mathfrak g}$ and the set ${\mathcal W}^\infty$ of all infinite ``reduced word'' of the Weyl group of ${\mathfrak g}$. The study is applied to the clas

Alberto Corso, Laura Ghezzi, Claudia Polini, Bernd Ulrich

Let $(R, {\mathfrak m})$ be a Noetherian local ring and let $I$ be an $R$-ideal. Inspired by the work of Hübl and Huneke, we look for conditions that guarantee the Cohen-Macaulayness of the special fiber ring ${\mathcal F}={\mathcal R}/{\mathfrak m}{\mathcal R}$ of $I$, where ${\mathcal R}$ denotes the Rees algebra of $I$. Our key idea is to require `good&#3

Joan E. Hart, Kenneth Kunen

If B is an infinite subset of omega and X is a topological group, let C^X_B be the set of all x in X such that <x^n : n in B> converges to 1. If F is a filter of infinite sets, let D^X_F be the union of all the C^X_B for B in F. The C^X_B and D^X_F are subgroups of X when X is abelian. In the circle group T, it is known that C^X_B always has measure 0. We sh

J. -P. Brasselet, D. Massey, A. J. Parameswaran, J. Seade

Several authors have proved Lefschetz type formulae for the local Euler obstruction. In particular, a result of this type is proved in [BLS].The formula proved in that paper turns out to be equivalent to saying that the local Euler obstruction, as a constructible function, satisfies the local Euler condition (in bivariant theory) with respect to general line

Holger Brenner

We provide the set of filters (saturated submonoids) in a commutative monoid with a topology (like the spectrum of a ring) and study the resulting spaces.

Holger Brenner

We study complements of hypersurfaces in schemes with respect to the property being affine.

Holger Brenner

We study different notions of slope of a vector bundle over a smooth projective curve with respect to ampleness and affineness in order to apply this to tight closure problems. This method gives new degree estimates from above and from below for the tight closure of a homogeneous $R_+$-primary ideal in a two-dimensional normal standard-graded algebra $R$ in

Alexader G. Elashvili, Alfons I. Ooms

The purpose of this paper is to study finite-dimensional Lie algebras over a field k of characteristic zero which admit a commutative polarization (CP). Among the many results and examples, it is shown that, if k is algebraically closed, the nilradical N of a parabolic subalgebra in A_n and C_n has such a CP. Using this fact a simple closed formula is derive

Alberto Bressan

Consider a stack of books, containing both white and black books. Suppose that we want to sort them out, putting the white books on the right, and the black books on the left (fig.~1). This will be done by a finite sequence of elementary transpositions. In other words, if we have a stack of all black books of length $a$ followed by a stack of all white books

Alberto Bressan

The theory of weak solutions for nonlinear conservation laws is now well developed in the case of scalar equations [3] and for one-dimensional hyperbolic systems [1, 2]. For systems in several space dimensions, however, even the global existence of solutions to the Cauchy problem remains a challenging open question. In this note we construct a conterexample

C. S. Rajan

We show the non-vanishing of cohomology groups of sufficiently small congruence lattices in $SL(1,D)$, where $D$ is a quaternion division algebras defined over a number field $E$ contained inside a solvable extension of a totally real number field. As a corollary, we obtain new examples of compact, arithmetic, hyperbolic three manifolds, with non-torsion fir

Valentina Barucci, Marco D&#39;Anna, Ralf Froberg

Two plane analytic branches are topologically equivalent if and only if they have the same multiplicity sequence. We show that having same semigroup is equivalent to having same multiplicity sequence, we calculate the semigroup from a parametrization, and we characterize semigroups for plane branches. These results are known, but the proofs are new. Furtherm

Valentina Barucci, Stefania Gabelli, Moshe Roitman

It is well known that a domain without proper strongly divisorial ideals is completely integrally closed. In this paper we show that a domain without {\em prime} strongly divisorial ideals is not necessarily completely integrally closed, although this property holds under some additional assumptions.

Igor Belegradek

We prove a result on equivariant deformations of flat bundles, and as a corollary, we obtain two ``splitting in a finite cover&#39;&#39; theorems for isometric group actions on Riemannian manifolds with infinite fundamental groups, where the manifolds are either compact of nonnegative Ricci curvature, or complete of nonnegative sectional curvature.

Igor Belegradek

We characterize co-Hopfian finitely generated torsion free nilpotent groups in terms of their Lie algebra automorphisms, and construct many examples of such groups.

Gail Letzter

A unified theory of quantum symmetric pairs is applied to q-special functions. Previous work characterized certain left coideal subalgebras in the quantized enveloping algebra and established an appropriate framework for quantum zonal spherical functions. Here a distinguished family of such functions, invariant under the Weyl group associated to the restrict

Franz Lehner

We continue the investigation of noncommutative cumulants. In this paper various characterizations of noncommutative Gaussian random variables are proved.

Pieter Collins

The Nielsen-Thurston theory of surface diffeomorphisms shows that useful dynamical information can be obtained about a surface diffeomorphism from a finite collection of periodic orbits.In this paper, we extend these results to homoclinic and heteroclinic orbits of saddle points. These orbits are most readily computed and studied as intersections of unstable

E. Elizalde, A. C. Tort

We consider a massive scalar field with arbitrary coupling in $\mathbf{S}^{1}\times \mathbf{S}^{3}$ space, which mimics the thermal expanding universe, and calculate explicitly all relevant thermodynamical functions in the low- and high-temperature regimes, extending previous analysis of entropy bounds and entropy/energy ratios performed in the conformal cas

G. W. Gibbons

It is shown that despite the possibility of a breakdown of hyperbolicity, the SU(2) Skyrme model can never exhibit bulk violations of Einstein causality because its energy momentum tensor satisfies the dominant energy condition. It also satisfies the strong energy condition. The Born-Infeld-Skyrme model also satisfies both the dominant and strong energy cond

Y. S. Myung, H. W. Lee

We study the wave equation for a minimally coupled massive scalar in D-dimensional de Sitter space. We compute the absorption cross section to investigate its cosmological horizon in the southern diamond. By analogy of the quantum mechanics, it is found that there is no absorption in de Sitter space. This means that de Sitter space is usually in thermal equi

Alexander Maloney, Andrew Strominger, Xi Yin

The description of string-theoretic s-branes at g_s=0 as exact worldsheet CFTs with a (lambda cosh X^0) or (lambda e^(X^0)) boundary interaction is considered. Due to the imaginary-time periodicity of the interaction under X^0 -> X^0 + 2 pi i, these configurations have intriguing similarities to black hole or de Sitter geometries. For example, the open strin

Alessandro Torrielli

The results of our research on noncommutative perturbative quantum field theory and its relation to string theory are exposed with details. 1) We give an introduction to noncommutative quantum field theory and its derivation from open string theory in an antisymmetric background. 2) We perform a perturbative Wilson loop calculation for 2D NCYM. We compare th

Hitoshi Nishino, Subhash Rajpoot

We present noncommutative nonlinear supersymmetric theories. The first example is a non-polynomial Akulov-Volkov-type lagrangian with noncommutative nonlinear global supersymmetry in arbitrary space-time dimensions. The second example is the generalization of this lagrangian to Dirac-Born-Infeld lagrangian with nonlinear supersymmetry realized in dimensions

Sharada Iyer Dutta, Mary Hall Reno, Ina Sarcevic

The ultrahigh energy neutrino cross section is well understood in the standard model for neutrino energies up to 10$^{12}$ GeV. Test of neutrino oscillations ($ν_μ\leftrightarrowν_τ$) from extragalactic sources of neutrinos are possible with large underground detectors. Measurments of horizontal air shower event rates at neutrino energies above 10$^{10}$ GeV

W. J. Huo, C. D. Lu, Z. J. Xiao

We calculate the branching ratios of $B_{s,d}\to γγ$ decay in the sequential fourth generation model. We find that the theoretical values of the branching ratios, ${\rm BR}(B_{s}\toγγ)$, including the contributions of $t&#39;$, are much different from the minimal standard model (SM) predictions. The new physics contribution can provide one to two orders enha

B. M. Gripaios, J. G. Milhano

A variational analysis of the pure SU(N) gauge theory in 3+1 dimensions at finite temperature is performed, extending the work of Kogan, Kovner and Milhano in hep-ph/0208053 . A de-confining phase transition is found at a temperature of 470 MeV, somewhat higher than lattice estimates. This value is however rather sensitive, for reasons which are discussed. A

S. P. Baranov, A. V. Lipatov, N. P. Zotov

In the framework of the k_T-factorization QCD approach we consider the production of b quark pairs in p\bar p collisions at the Fermilab Tevatron. We investigate the dependence of the b quark, B meson and decay muon differential cross sections on the different forms of unintegrated gluon distributions. The analysis also covers the azimuthal correlations betw

K. J. Eskola, H. Honkanen, V. J. Kolhinen, C. A. Salgado

The DGLAP analyses of the nuclear parton distribution functions (nPDF) based on the global fits to the data are reviewed, and the results from EKS98 and HKM are compared. The usefulness of measuring hard probes in $pA$ collisions, at the LHC in particular, is demonstrated.

P. Kroll

The basic theoretical ideas of the handbag mechanism for wide-angle exclusive scattering reactions are discussed and, with regard to the present experimental program carried out at JLab, its application to Compton scattering is reviewed in some detail. Results for other wide-angle reactions such as two-photon annihilations into pairs of hadrons or virtual Co

A. Bornheim

We present final measurements of thirteen charmless hadronic B decay modes from the CLEO experiment. The decay modes include the ten pipi, Kpi, and KKbar final states and new limits on dibaryonic final states, ppbar, pLambdabar, and LambdaLambdabar, as well as a new determination of the ratio BR(B-> DK)/BR(B-> Dpi). The results are based on the full CLEO II

Claudio Simeone

The relation between a recently proposed path integral for minisuperspaces and different canonical quantizations is established. The step of the procedure where a choice between non equivalent theories is made is identified. Coordinates avoiding such a choice are found for a class of homogeneous cosmologies.

Pieter-Jan De Smet

We classify all five-dimensional Einstein manifolds that are static, have an SO(3) isometry group and have Petrov type 22. We use this classification to show that the localized black hole in the Randall-Sundrum scenario necessarily has Petrov type 4.

Carlos Kozameh, Ezra T Newman, Pawel Nurowski

Necessary and sufficient conditions for a space-time to be conformal to an Einstein space-time are interpreted in terms of curvature restrictions for the corresponding Cartan conformal connection.

P. S. Custódio, J. E. Horvath

We analyze the thermodynamical behavior of black holes in closed finite boxes. First the black hole mass evolution is analyzed in an initially empty box. Using the conservation of the energy and the Hawking evaporation flux, we deduce a minimal volume above which one black hole can loss all of its mass to the box, a result which agrees with the previous anal

H. -J. Schmidt

We show that the square of the Weyl tensor can be negative by giving an example.

Alex Brodsky, Nicholas Pippenger

Among their many uses, growth processes (probabilistic amplification), were used for constructing reliable networks from unreliable components, and deriving complexity bounds of various classes of functions. Hence, determining the initial conditions for such processes is an important and challenging problem. In this paper we characterize growth processes by

David Eppstein, John M. Sullivan, Alper Ungor

We show it is possible to tile three-dimensional space using only tetrahedra with acute dihedral angles. We present several constructions to achieve this, including one in which all dihedral angles are less than $77.08^\circ$, and another which tiles a slab in space.

Volodymyr Myrnyy

The article deals with a kind of recursive function templates in C++, where the recursion is realized corresponding template parameters to achieve better computational performance. Some specialization of these template functions ends the recursion and can be implemented using optimized hardware dependent or independent routines. The method is applied in addi

Jarmo Laaksolahti, Magnus Boman

An anticipatory system for guiding plot development in interactive narratives is described. The executable model is a finite automaton that provides the implemented system with a look-ahead. The identification of undesirable future states in the model is used to guide the player, in a transparent manner. In this way, too radical twists of the plot can be avo

A. B. Kuzmenko, N. Tombros, H. J. A. Molegraaf, M. Grueninger

We present the c-axis optical conductivity $σ_{1c}(ω, T)$ of underdoped ($x$ = 0.12) and optimally doped ($x$ = 0.15) LSCO from 4 meV to 1.8 eV obtained by a combination of reflectivity and transmission spectra. In addition to the opening of the superconducting gap, we observe an {\it increase} of conductivity above the gap up to 270 meV with a maximal effec

X. J. Chen, C. L. Zhang, C. C. Almasan, J. S. Gardner

We report anisotropic resistivity measurements on a La$_{1.2}$Sr$_{1.8}$Mn$_{2}$O$_{7}$ single crystal over a temperature $T$ range from 2 to 400 K and in magnetic fields $H$ up to 14 T. For $T\geq 218$ K, the temperature dependence of the zero-field in-plane $ρ_{ab}(T)$ resistivity obeys the adiabatic small polaron hopping mechanism, while the out-of-plane

L. Arrachea, D. Dalidovich, V. Dobrosavljević, M. J. Rozenberg

The quantum critical behavior of the Ising glass in a magnetic field is investigated. We focus on the spin glass to paramagnet transition of the transverse degrees of freedom in the presence of finite longitudinal field. We use two complementary techniques, the Landau theory close to the T=0 transition and the exact diagonalization method for finite systems.

Andrew D. Rutenberg, Andrew J. Richardson, Claire J. Montgomery

Particles moving along curved trajectories will diffuse if the curvature fluctuates sufficiently in either magnitude or orientation. We consider particles moving at a constant speed with either a fixed or with a Gaussian distributed curvature magnitude. At small speeds the diffusivity is independent of the speed. At larger particle speeds, the diffusivity de

A. V. Goltsev, D. M. Rowe, V. L. Kuznetsov, L. A. Kuznetsova

A theoretical study has been undertaken of the Peltier effect in normal metal - insulator - heavy fermion metal junctions. The results indicate that, at temperatures below the Kondo temperature, such junctions can be used as electronic microrefrigerators to cool the normal metal electrode and are several times more efficient in cooling than the normal metal

J. R. Kirtley, C. C. Tsuei, F. Tafuri

We have observed spontaneous fluxoid generation in thin-film rings of the amorphous superconductor Mo$_3$Si, cooled through the normal-superconducting transition, as a function of quench rate and externally applied magnetic field, using a variable sample temperature scanning SQUID microscope. Our results can be explained using a model of freezout of thermall

Rosario Fazio, F. W. J. Hekking, J. P. Pekola

We study adiabatic charge transfer in a superconducting Cooper pair pump, focusing on the influence of current measurement on coherence. We investigate the limit where the Josephson coupling energy $E_J$ between the various parts of the system is small compared to the Coulomb charging energy $E_C$. In this case the charge transferred in a pumping cycle $Q_P

Nicola Cufaro Petroni, Salvatore De Martino, Silvio De Siena, Fabrizio Illuminati

The formation of the beam halo in charged particle accelerators is studied in the framework of a stochastic-hydrodynamic model for the collective motion of the particle beam. In such a stochastic-hydrodynamic theory the density and the phase of the charged beam obey a set of coupled nonlinear hydrodynamic equations with explicit time-reversal invariance. Thi

Haye Hinrichsen

The Langevin equation for the pair contact process with diffusion (PCPD) 2A->3A, 2A->0 can be mapped by a Cole-Hopf transformation to a Kardar-Parisi-Zhang equation in a potential which has been discussed previously in the context of non-equilibrium wetting. Using this transformation the phase transition in the PCPD manifests itself as a depinning transition

Ron Lifshitz

It is argued that the prevailing definition of quasicrystals, requiring them to contain an axis of symmetry that is forbidden in periodic crystals, is inadequate. This definition is too restrictive in that it excludes an important and interesting collection of structures that exhibit all the well-known properties of quasicrystals without possessing any forbi

I. Gomes, C. Mirasso, R. Toral, O. Calvo

We study the stochastic resonance phenomenon occurring in electronic Chua circuits operating in the chaotic regime when the forcing signal is modulated at relatively high frequency, of the order of magnitude of the main Chua frequency in the absence of forcing ($f_o$). In all the cases, a clear maximum in the signal-to-noise ratio for an intermediate noise l

Nicola Cufaro Petroni, Salvatore De Martino, Silvio De Siena, Fabrizio Illuminati

We introduce a description of the collective transverse dynamics of charged (proton) beams in the stability regime by suitable classical stochastic fluctuations. In this scheme, the collective beam dynamics is described by time--reversal invariant diffusion processes deduced by stochastic variational principles (Nelson processes). By general arguments, we sh

H. Yamada, T. Fukui

We study Anderson localization of non-interacting random hopping fermions on bipartite lattices in two dimensions, focusing our attention to strong disorder features of the model. We concentrate ourselves on specific models with a linear dispersion in the vicinity of the band center, which can be described by a Dirac fermion in the continuum limit. Based on

P. Miranovic, N. Nakai, M. Ichioka, K. Machida

Orientational field-dependence of the zero energy density of states (ZEDOS) is calculated for superconductors with the polar state (line node), axial state (point node) and 3D d-wave state. Depending on the gap topology and relative field direction the field dependencies of ZEDOS sensitively differ, providing us a useful and practical method to identify the

Bing Dong, H. L. Cui, S. Y. Liu, X. L. Lei

We investigate the equilibrium and out-of-equilibrium Kondo effects in a single-level interacting quantum dot connected to two ferromagnetic leads. Within the non-crossing approximation, we calculate the total density of states (DOS), the linear conductance, and the nonlinear differential conductance for both the parallel and the anti-parallel alignments of

Hsi-Sheng Goan

We provide a unified picture for the master equation approach and the quantum trajectory approach to a measurement problem of a two-state quantum system (a qubit), an electron coherently tunneling between two coupled quantum dots (CQD&#39;s) measured by a low transparency point contact (PC) detector. We show that the master equation of ``partially&#39;&#39;

Sean N. Raymond, Paula Szkody, Suzanne L. Hawley, Scott F. Anderson

We have identified 109 White Dwarf (WD) - M dwarf pairs in the Sloan Digital Sky Survey (SDSS) with g < 20th magnitude. For each system we determined the temperature of the WD primary and the spectral type of the M dwarf secondary. Using H-alpha emission as a proxy for the chromospheric activity level of the M dwarf, we investigated correlations between the

John P. Blakeslee, Zlatan I. Tsvetanov, Adam G. Riess, Holland C. Ford

We present observations of the first two supernovae discovered with the recently installed Advanced Camera for Surveys (ACS) on the Hubble Space Telescope. The supernovae were found in Wide Field Camera images of the Hubble Deep Field North taken with the F775W, F850LP, and G800L optical elements as part of the ACS guaranteed time observation program. Spectr

T. A. Rector, J. T. Stocke

While BL Lacertae objects are widely believed to be highly beamed, low-luminosity radio galaxies, many radio-selected BL Lacs have extended radio power levels and optical emission lines that are too luminous to be low-luminosity radio galaxies. Also, Stocke & Rector discovered an excess of MgII absorption systems along BL Lac sightlines compared to quasars,

S. M. Rucinski, C. C. Capobianco, W. Lu, H. DeBond

Radial-velocity measurements and sine-curve fits to the orbital velocity variations are presented for the seventh set of ten close binary systems: V410 Aur, V523 Cas, QW Gem, V921 Her, V2357 Oph, V1130 Tau, HN UMa, HX UMa, HD 93917, NSV 223. All systems, but three (V523 Cas, HD 93917, NSV 223), were discovered photometrically by the Hipparcos mission. All sy

A. Arrieta, S. Torres-Peimbert

Eleven objects that have been reported as proto-planetary nebula or as young planetary nebulae that show very extended Halpha wings are presented. The extension of these wings is larger than 800 km/s. Data for two symbiotic stars that show this same characteristic is also presented. Raman scattering is the mechanism that best explains the wings in 10 of the

T. A. Rector, D. C. Gabuzda, J. T. Stocke

We present VLA and first-epoch VLBA observations that are part of a program to study the parsec-scale radio structure of a sample of fifteen high-energy-peaked BL Lacs (HBLs). The sample was chosen to span the range of logarithmic X-ray to radio flux ratios observed in HBLs. As this is only the first epoch of observations, proper motions of jet components ar

Alejandro Gangui

In the framework of inflationary models with non-vacuum initial states for cosmological perturbations, we study non-Gaussian signatures on the cosmic microwave background radiation produced by a broken-scale-invariant model which incorporates a feature at a privileged scale in the primordial power spectrum.

Hans-Rainer Kl&#34;ockner, Willem A. Baan, Michael A. Garrett

Here we report on observations of powerful hydroxyl (OH) line emissions that trace the obscuring material within the circumnuclear environment of the galaxy Markarian 231. The hydroxyl (mega)-maser emission shows the characteristics of a rotating, dusty, molecular torus (or thick disk) located between 30 and 100 pc from the central engine. We now have a clea

J. C. Charlton, J. Ding, S. G. Zonak, C. W. Churchill

High resolution optical (HIRES/Keck) and UV (STIS/HST) spectra, covering a large range of chemical transitions, are analyzed for three single-cloud weak MgII absorption systems along the line of sight toward the quasar PG 1634+706. Weak MgII absorption lines in quasar spectra trace metal-enriched environments that are rarely closely associated with the most

John S. Mulchaey, David S. Davis, Richard F. Mushotzky, David Burstein

A search was conducted for a hot intragroup medium in 109 low-redshift galaxy groups observed with the ROSAT PSPC. Evidence for diffuse, extended X-ray emission is found in at least 61 groups. Approximately one-third of these detections have not been previously reported in the literature. Most of the groups are detected out to less than half of the virial ra

M. Barden, M. D. Lehnert, L. Tacconi, R. Genzel

We describe the first results of a programme to obtain rotation curves of z~1 disc galaxies in the near-infrared using the Ha emission line in order to study the Tully-Fisher relation. To put any observed evolution into perspective and to investigate any possible selection biases, we constructed a control sample of low redshift galaxies that had rotation vel

M. A. Jimenez-Garate, N. S. Schulz, H. L. Marshall

During the disk-mediated accretion phase, the high-resolution X-ray spectrum of the low-mass X-ray binary system EXO 0748-676 reveals a photoionized plasma which is orbiting the neutron star. Our observations with the Chandra High Energy Transmission Grating Spectrometer (HETGS) constrain the structure of the upper layers of the accretion disk, by means of t