January 2004 arXiv papers — page 12

O. V. Man'ko, V. I. Man'ko

Probability representation entropy (tomographic entropy) of arbitrary quantum state is introduced. Using the properties of spin tomogram to be standard probability distribution function the tomographic entropy notion is discussed. Relation of the tomographic entropy to Shannon entropy and von Neumann entropy is elucidated.

A. Andre, A. S. Sorensen, M. D. Lukin

We analyze the effect of realistic noise sources for an atomic clock consisting of a local oscillator that is actively locked to a spin-squeezed (entangled) ensemble of $N$ atoms. We show that the use of entangled states can lead to an improvement of the long-term stability of the clock when the measurement is limited by decoherence associated with instabili

Gavriel Segre

Asher Peres' proof that a violation of No Cloning Theorem would imply a violation of the Second Law of Thermodynamics is shown not to take into account the algorithmic-information's contribution to the Thermodynamical Entropy of the semi-permeable membranes of Peres' engine.

Thomas Petermann, Paolo De Los Rios

Especially in lattice structured populations, homogeneous mixing represents an inadequate assumption. Various improvements upon the ordinary pair approximation based on a number of assumptions concerning the higher-order correlations have been proposed. To find approaches that allow for a derivation of their dynamics remains a great challenge. By representin

Ming S. Liu, B. D. Todd, Richard J. Sadus

F1-ATPase catalyses ATP hydrolysis and converts the cellular chemical energy into mechanical rotation. The hydrolysis reaction in F1-ATPase does not follow the widely believed Michaelis-Menten mechanism. Instead, the hydrolysis mechanism behaves in an ATP-dependent manner. We develop a model for enzyme kinetics and hydrolysis cooperativity of F1-ATPase which

Rodrick Wallace

We adapt an information theory analysis of interacting cognitive biological and social modules to the problem of the global neuronal workspace, the current standard neuroscience picture of consciousness. Tunable punctuation emerges in a natural manner, suggesting the possibility of fitting appropriate phase transition power law, and, away from transition, ge

J. E. Clendenin, A. Brachmann, E. L. Garwin, S. Harvey

Future colliders such as NLC and JLC will require a highly-polarized macropulse with charge that is more than an order of magnitude beyond that which could be produced for the SLC. The maximum charge from the SLC uniformly-doped GaAs photocathode was limited by the surface charge limit (SCL). The SCL effect can be overcome by using an extremely high (>1019 c

D. Y. Churmakov, I. V. Meglinski, S. A. Piletsky, D. A. Greenhalgh

A novel Monte Carlo technique of simulation of spatial fluorescence distribution within the human skin is presented. The computational model of skin takes into account the spatial distribution of fluorophores, which would arise due to the structure of collagen fibres, compared to the epidermis and stratum corneum where the distribution of fluorophores is ass

Oleh Danyliv, Lev Kantorovich

With the aim of future applications in quantum mechanical embedding in extended systems such as crystals, we suggest a simple and computationally efficient method which enables construction of a set of nonorthogonal highly localized one-electron orbitals for periodic nonmetallic crystals which reflect their chemical nature. The orbitals are also used to buil

Lev Kantorovich, Oleh Danyliv

Methods for calculating an electron density of a periodic crystal constructed using non-orthogonal localised orbitals are discussed. We demonstrate that an existing method based on the matrix expansion of the inverse of the overlap matrix into a power series can only be used when the orbitals are highly localised (e.g. ionic systems). In other cases includin

Fabian Huegging

For the ATLAS Pixel Detector fast readout electronics has been successfully developed and tested. Main attention was given to the ability to detect small charges in the order of 5,000 electrons within 25 ns in the harsh radiation environment of LHC together with the challenge to cope with the huge amount of data generated by the 80 millions channels of the P

I. V. Meglinski, D. Y. Churmakov, A. N. Bashkatov, E. A. Genina

The purpose of the present work is a theoretical examination of how localized skin-tissue dehydration affects the depth of the confocal probing and what depth of effective detection can be reached with the chemical administration of skin tissues. A semi-infinite multilayer Monte Carlo model is used to estimate spatial localization of the output signal offere

R. L. Mills, P. C. Ray, R. M. Mayo, M. Nansteel

It was demonstrated that low pressure (~0.2 Torr) water vapor plasmas generated in a 10 mm inner diameter quartz tube with an Evenson microwave cavity show at least two features which are not explained by conventional plasma models. First, significant (> 0.25 nm) hydrogen Balmer_ line broadening, of constant width, up to 5 cm from the microwave coupler was r

Laszlo E. Szabo

The main content of this paper has been moved into the new version of physics/0308035.

Jean-Marc Sparenberg

R-matrix analyses of the 12C + alpha elastic-scattering phase shifts deduced from a recent high-precision measurement of the differential cross sections are performed. The l=0 phase shifts constrain the R-matrix radius a around 5.85 fm, while the l=2 phase shifts lead to a strong constrain neither on a nor on the asymptotic normalization constant C of the 2+

H. Zhan, A. Nogga, B. R. Barrett, J. P. Vary

Nuclear many-body calculations are computationally demanding. An estimate of their accuracy is often hampered by the limited amount of computational resources even on present-day supercomputers. We provide an extrapolation method based on perturbation theory, so that the binding energy of a large basis-space calculation can be estimated without diagonalizing

S. Juchem, W. Cassing, C. Greiner

We solve the Kadanoff-Baym equations for nonequilibrium initial configurations of the $ϕ^4$-theory in 2+1 dimensions and compare to explicit solutions of generalized transport equations for the same theory. The latter transport equations are derived from the Kadanoff-Baym equation in a first order gradient expansion in phase space and explicitly retain the o

P. Fröbrich

Recent progress in the theory of fission of hot nuclei is reported. We discuss in particular the properties of the friction formfactor as function of the deformation (and possibly of the temperature) which are necessary to reproduce data concerning fission of hot nuclei and its accompanying light particle and $γ$-ray emission. Recent theoretical work gives s

Sukhendusekhar Sarkar, M. Saha Sarkar

Using recent experimental information for 132Sn region, an empirical Hamiltonian is obtained by some modifications of a Hamiltonian (CW5082) originally derived from the 208Pb region. Shell model calculations with the new Hamiltonian shows remarkable improvement in the predictive power when compared with the available experimental results. It overcomes many l

Jens Jorgen Gaardhoje

Heavy ion collisions at RHIC energies (Au+Au collisions at $\sqrt{s_{NN}}=200$ GeV) exhibit significant new features as compared to earlier experiments at lower energies. The reaction is characterized by a high degree of transparency of the collisions partners leading to the formation of a baryon-poor central region. In this zone, particle production occurs

F. E. Wietfeldt, C. Trull, R. Anderman, F. B. Bateman

We describe a beta electron spectrometer for use in an upcoming experiment that will measure the beta-antineutrino correlation coefficient (a-coefficient) in neutron beta decay. Electron energy is measured by a thick plastic scintillator detector. A conical array of plastic scintillator veto detectors is used to suppress events where the electron backscatter

H. Scheit, O. Niedermaier, M. Pantea, F. Aksouh

After the successful commissioning of the radioactive beam experiment at ISOLDE (REX-ISOLDE) - an accelerator for exotic nuclei produced by ISOLDE - first physics experiments using these beams were performed. Initial experiments focused on the region of deformation in the vicinity of the neutron-rich Na and Mg isotopes. Preliminary results show the high pote

Anna L. Lin, Aric Hagberg, Ehud Meron, Harry L. Swinney

Various resonant and near-resonant patterns form in a light-sensitive Belousov-Zhabotinsky (BZ) reaction in response to a spatially-homogeneous time-periodic perturbation with light. The regions (tongues) in the forcing frequency and forcing amplitude parameter plane where resonant patterns form are identified through analysis of the temporal response of the

D. Gomez-Ullate, N. Kamran, R. Milson

We propose a more direct approach to constructing differential operators that preserve polynomial subspaces than the one based on considering elements of the enveloping algebra of sl(2). This approach is used here to construct new exactly solvable and quasi-exactly solvable quantum Hamiltonians on the line which are not Lie-algebraic. It is also applied to g

E. Caliceti, S. Graffi

Let $H$ be any $\PT$ symmetric Schrödinger operator of the type $ -\hbar^2Δ+(x_1^2+...+x_d^2)+igW(x_1,...,x_d)$ on $L^2(\R^d)$, where $W$ is any odd homogeneous polynomial and $g\in\R$. It is proved that $¶H$ is self-adjoint and that its eigenvalues coincide (up to a sign) with the singular values of $H$, i.e. the eigenvalues of $\sqrt{H^\ast H}$. Moreover w

Gavriel Segre

Some little considerations concerning the application of the Theory of Dirichlet Forms to stocastic variational principle on riemannian manifolds are performed

Eleny-Nicoleta Ionel, Thomas H. Parker

We define relative Gromov-Witten invariants of a symplectic manifold relative to a codimension two symplectic submanifold. These invariants are the key ingredients in the symplectic sum formula of [IP4]. The main step is the construction of a compact space of `V-stable' maps. Simple special cases include the Hurwitz numbers for algebraic curves and the e

Stefano Vidussi

This short note presents a simple construction of nonisotopic symplectic tori representing the same primitive homology class in the symplectic 4-manifold E(1)_K, obtained by knot surgery on the rational elliptic surface E(1) with the left-handed trefoil knot K. E(1)_K has the simplest homotopy type among simply-connected symplectic 4-manifolds known to exhib

Zhi-Ming Luo

We show that the category of presheaves of simplicial groupoids on a site $\mathcal{C}$ is a right proper simplicial model category. We define $G$-torsor of presheaf of 2-groupoids $G$, presheaf of simplicial groups $G$ and presheaf of simplicial groupoids $G$ on a site $\mathcal{C}$ and classify $G$-torsors by the homotopy classes $[\ast, \bar{W}G]$.

Liviu I. Nicolaescu

We use a probabilistic approach to describe the behavior as $n -> \infty$ of the Laplace transforms of $P^n$, where $P$ a fixed complex polynomial. As a consequence we obtain a new elementary proof of an result of Gillis-Ismail-Offer in the combinatorial theory of derangements.

Patrick Bahls

We show that right-angled Coxeter groups are relatively hyperbolic in the sense defined by Farb, relative to a natural collection of rank-2 parabolic subgroups.

M. Andrle, L. Rebollo-Neira, E. Sagianos

A recursive approach for shrinking coefficients of an atomic decomposition is proposed. The corresponding algorithm evolves so as to provide at each iteration a) the orthogonal projection of a signal onto a reduced subspace and b) the index of the coefficient to be disregarded in order to construct a coarser approximation minimizing the norm of the residual

Andreas Wannebo

An technically interesting proof of a known theorem.

Bernhard Kroetz, Michael Otto

We apply techniques from symplectic geometry to extend and give a new proof of the complex convexity theorem of Gindikin-Kroetz.

Hilmar Hauer, Ignazio Longhi

The exceptional zero conjecture relates the first derivative of the $p$-adic $L$-function of a rational elliptic curve with split multiplicative reduction at $p$ to its complex $L$-function. Teitelbaum formulated an analogue of Mazur and Tate's refined (multiplicative) version of this conjecture for elliptic curves over the rational function field $\FQ(T

Timothy Porter

The notes were prepared for a series of talks that I gave in Hagen in late June and early July 2003, and, with some changes, in the University of La Laguña, the Canary Islands, in September, 2003. They aim (i) to revisit some oldish material on abstract homotopy and simplicial ly enriched categories, that seems to be being used in today's resurgence of i

E. Celeghini, P. P. Kulish

Triangular deformation of the orthosymplectic Lie superalgebra osp(1|4) is defined by chains of twists. Corresponding classical r-matrix is obtained by a contraction procedure from the trigonometric r-matrix. The carrier space of the constant r-matrix is the Borel subalgebra.

Y. Chen, A. Its

In this paper we study those polynomials orthogonal with respect to a particular weight over the union of disjoint intervals first introduced by N.I. Akhiezer, via a reformulation as a matrix factorization or Riemann-Hilbert problem. This approach complements the method proposed in a previous paper, that involves the construction of a certain meromorphic fun

Anton Deitmar

We formulate a conjectural Lefschetz formula for locally symmetric spaces of finite volume. The formula can be verified in the compact case and for Riemann surfaces.

Pascal Collin, Robert Kusner, William H. Meeks, III

This paper develops new tools for understanding surfaces with more than one end (and usually, of infinite topology) which properly minimally embed into Euclidean three-space. On such a surface, the set of ends forms a compact Hausdorff space, naturally ordered by the relative heights of the ends in space. One of our main results is that the middle ends of th

Patrick Bahls

A Coxeter system is called two-dimensional if its associated Davis complex is two-dimensional (equivalently, every spherical subgroup has rank less than or equal to 2). We prove that given a two-dimensional system (W,S) and any other system (W,S') which yields the same reflections, the diagrams corresponding to these systems are isomorphic, up to the ope

Linus Kramer, Katrin Tent

Asymptotic cones of metric spaces were first invented by Gromov. They are metric spaces which capture the 'large-scale structure' of the underlying metric space. Later, van den Dries and Wilkie gave a more general construction of asymptotic cones using ultrapowers. Certain facts about asymptotic cones, like the completeness of the metric space, now f

Michael Anshelevich

We continue the investigation of the Levy processes on a q-deformed full Fock space started in a previous paper. First, we show that the vacuum vector is cyclic and separating for the algebra generated by such a process. Next, we describe a chaotic representation property in terms of multiple integrals with respect to diagonal measures, in the style of Nuala

Arkady Berenstein, Sergey Fomin, Andrei Zelevinsky

We continue the study of cluster algebras initiated in math.RT/0104151 and math.RA/0208229. We develop a new approach based on the notion of an upper cluster algebra, defined as an intersection of certain Laurent polynomial rings. Strengthening the Laurent phenomenon from math.RT/0104151, we show that, under an assumption of "acyclicity", a cluster a

M. Cvetic, G. W. Gibbons, C. N. Pope

We study properties of supergravity theories with non-compact gaugings, and their higher-dimensional interpretations via consistent reductions on the inhomogeneous non-compact hyperboloidal spaces {\cal H}^{p,q}. The gauged supergravities are free of ghosts, despite the non-compactness of the gauge groups. We give a general discussion of the existence of sta

H. Lu, J. F. Vazquez-Poritz

We review two ways in which smooth cosmological evolution between two de Sitter phases can be obtained from M/string-theory. Firstly, we perform a hyperbolic reduction of massive IIA* theory to D=6 N=(1,1) SU(2)xU(1) gauged de Sitter supergravity, which supports smooth cosmological evolution between dS_4 x S^2 and a dS_6-type geometry. Secondly, we obtain fo

Alexander B. Zamolodchikov

I show that the expectation value of the composite field $T{\bar T}$, built from the components of the energy-momentum tensor, is expressed exactly through the expectation value of the energy-momentum tensor itself. The relation is derived in two-dimensional quantum field theory under broad assumptions, and does not require integrability.

F. Strocchi

The problems which arise for a relativistic quantum mechanics are reviewed and critically examined in connection with the foundations of quantum field theory. The conflict between the quantum mechanical Hilbert space structure, the locality property and the gauge invariance encoded in the Gauss' law is discussed in connection with the various quantizatio

Kentaro Hori

We study boundary renormalization group flows of N=2 minimal models using Landau-Ginzburg description of B-type. A simple algebraic relation of matrices is relevant. We determine the pattern of the flows and identify the operators that generate them. As an application, we show that the charge lattice of B-branes in the level k minimal model is Z_{k+2}. We al

Vladimir M. Braun, Einan Gardi, Stefan Gottwald

Power corrections to exclusive processes are usually calculated using models for twist-four distribution amplitudes (DA) which are based on the leading-order terms in the conformal expansion. In this work we develop a different approach which does not rely on conformal symmetry but is based instead on renormalon analysis. This way we obtain an upper bound fo

D. Yu. Ivanov, B. Pire, L. Szymanowski, O. V. Teryaev

Electroproduction of two vector mesons with a large rapidity gap between them provides the first feasible selective access to chiral-odd GPDs. The scattering amplitude of the process $ γ^* N \to ρ_L^0 ρ_T^+ N'$ may be represented as a convolution of an impact factor describing the $γ^* \to ρ_L^0$ transition and an amplitude describing the $N\to ρ_T^+ N&#

Egle Tomasi-Gustafsson, Michail P. Rekalo

The spin structure of the matrix element for the reactions $γ+ N\to Y_c +{D}^*$, where $Y_c=Λ_c^+(2285)$, $Σ_c(2455)$ are charmed baryons with spin 1/2, and $D^*(2010)$ is the vector charmed meson, can be parametrized, in collinear regime, in terms of three independent scalar amplitudes, which are functions of the photon energy $E_γ$, only. In framework of a

K. Matsuda

We investigate a model that the Yukawa coupling form is constructed by two kinds of matrix (M_0 and M_1). For example, in the SO(10) GUT model, M_0 and M_1 are Yukawa couplings generated by the 10 and 126 Higgs scalars. We study how this model can give the observed mass and mixings of quarks and leptons. Parameter fitting is fully scanned by assuming all the

Dan Hooper

In this article, based on the talk given at the Cracow Epiphany Conference on Astroparticle Physics, I discuss some of the opportunities provided by high-energy and ultra-high energy neutrino astronomy in probing particle physics beyond the standard model. Following a short summary of current and next generation experiments, I review the prospects for observ

Defu Hou, Qun Wang, Dirk H. Rischke

We derive a generalized Ward identity for color-superconducting quark matter via the functional integral approach. The identity implies the gauge independence of the color-superconducting gap parameter on the quasi-particle mass shell to subleading order in covariant gauge.

Timothy L. Barklow

Methods for extracting Higgs boson signals at a 1 TeV center-of-mass energy e+e- linear collider are described. In addition, estimates are given for the accuracy with which branching fractions can be measured for Higgs boson decays to bb, WW, gluon-gluon, and gamma-gamma.

H. Wulandari, J. Jochum, W. Rau, F. von Feilitzsch

The new detection concept applied for the direct WIMP search experiment CRESST II, which enables a clear discrimination between electron recoils and nuclear recoils, will leave neutrons as the main background. This background will soon limit the sensitivity of the experiment and therefore become an important issue for the next phase of CRESST. We have perfor

Paolo Franzini

The original plan of a vigorous program of frontier physics at LNF, based on the phi-factory DAFNE with the KLOE detector, has not yet reached its major aim in the study of discrete symmetries in the neutral kaon system. It has however led to the education of a new generation of particle and accelerator physicists. With such invaluable human resources it see

J. Manuel Garcia-Islas

In this paper we report some results on the expectation values of a set of observables introduced for 3-dimensional Riemannian quantum gravity with positive cosmological constant, that is, observables in the Turaev-Viro model. Instead of giving a formal description of the observables, we just formulate the paper by examples. This means that we just show how

Elspeth W. Allen, Elizabeth Buckmiller, Lior M. Burko, Richard H. Price

In numerical computations of Einstein's equations for black hole spacetimes, it will be necessary to use approximate boundary conditions at a finite distance from the holes. We point out here that ``tails,'' the inverse power-law decrease of late-time fields, cannot be expected for such computations. We present computational demonstrations and di

Lorenzo Iorio

The possibility of performing post-Newtonian gravitoelectromagnetic measurements with a joint LAGEOS-LAGEOS II-OPTIS space-based mission is investigated

Dave Pandres,, Edward L. Green

A theory has been presented previously in which the geometrical structure of a real four-dimensional space time manifold is expressed by a real orthonormal tetrad, and the group of diffeomorphisms is replaced by a larger group. The group enlargement was accomplished by including those transformations to anholonomic coordinates under which conservation laws a

David Delphenich

This article is a continuation of a previous work that dealt with the topological obstructions to the reductions of the bundle of linear frames on a spacetime manifold for a particular chain of subgroups of GL(4). In this article, the corresponding geometrical information, such as connections, torsion, curvature, and automorphisms of the reductions will be d

Hernando Quevedo, Julio G. Tafoya

We present a first attempt to apply the approach of deformation quantization to linearized Einstein's equations. We use the analogy with Maxwell equations to derive the field equations of linearized gravity from a modified Maxwell Lagrangian which allows the construction of a Hamiltonian in the standard way. The deformation quantization procedure for fre

A. Robledo

It is pointed out that the dynamics of the order parameter at a thermal critical point obeys the precepts of the nonextensive Tsallis statistics. We arrive at this conclusion by putting together two well-defined statistical-mechanical developments. The first is that critical fluctuations are correctly described by the dynamics of an intermittent nonlinear ma

Layachi Hadji

We show that the interaction of a particle with a directionally solidified interface induces the onset of morphological instability provided that the particle-interface distance falls below a critical value. This instability occurs at pulling velocities that are below the threshold for the onset of the Mullins-Sekerka instability. The expression for the crit

A. Robledo

We go over our finding that the dynamics at the noise-perturbed edge of chaos in logistic maps is comparable to that observed in supercooled liquids close to vitrification. That is, the three major features of glassy dynamics in structural glass formers, two-step relaxation, aging, and a relationship between relaxation time and configurational entropy, are d

Grzegorz Szamel

We consider a toy model for glassy dynamics of colloidal suspensions: a single Brownian particle diffusing among immobile obstacles. If Gaussian factorization of static density fluctuations is assumed, this model can be solved without factorization approximation for any dynamic correlation function. The solution differs from that obtained from the ideal mode

M. Kriener, C. Zobel, A. Reichl, J. Baier

We present an investigation of the influence of structural distortions in charge-carrier doped \lmco by substituting La$^{3+}$ with alkaline earth metals of strongly different ionic sizes, that is M = Ca$^{2+}$, Sr$^{2+}$, and Ba$^{2+}$, respectively. We find that both, the magnetic properties and the resistivity change non-monotonously as a function of the

Anatoly Yu. Smirnov

An application of impedance measurement technique (IMT) for a detection of quantum tunneling in molecular structures is investigated. A charged particle which tunnels in a two-well potential is electrically coupled to a high-quality superconducting LC-circuit(tank) that makes possible a measurement of the electric susceptibility of the molecule at the resona

A. A. Burkov, Leon Balents

We consider the problem of spin relaxation in a two-dimensional electron gas (2DEG) in a perpendicular magnetic field. We assume that the spin relaxation is induced by the Rashba spin-orbit (SO) interaction, which appears due to the inversion asymmetry of the confining potential. Our solution is based on a microscopic evaluation of the spin density response

T. Schneider

We review and refine the finite size scaling analysis of specific heat and London penetration depths data of cuprate superconductors and compare it to the analysis of specific heat measurements near the superfluid transition of 4He confined to 1mum^3 cylindrical boxes. This system crosses from 3D to 0D behavior near the transition. This has a marked effect o

M. J. Greenall, A. O. Parry, J. M. Romero-Enrique

We investigate interfacial structural and fluctuation effects occurring at continuous filling transitions in 3D wedge geometries. We show that fluctuation-induced wedge covariance relations that have been reported recently for 2D filling and wetting have mean-field or classical analogues that apply to higher-dimensional systems. Classical wedge covariance em

B. Limbach, P. vom Stein, C. Wallisser, R. Schaefer

We report measurements on single-electron pumps, consisting of two metallic islands formed by three tunnel junctions in series. We focus on the linear-response conductance as a function of gate voltage and temperature of three samples with varying system parameters. In all cases, strong quantum fluctuation phenomena are observed by a log(k_B T/(2 E_co)) redu

L. Yin, V. K. Vlasko-Vlasov, A. Rydh, J. Pearson

The generation of surface plasmon polaritons (SPP's) at isolated nanoholes in 100 nm thick Au films is studied using near-field scanning optical microscopy (NSOM). Finite-difference time-domain calculations, some explicitly including a model of the NSOM tip, are used to interpret the results. We find the holes act as point-like sources of SPP's and d

Denis Ullmo, Hong Jiang, Weitao Yang, Harold U. Baranger

We analyze the ground state energy and spin of quantum dots obtained from spin density functional theory (SDFT) calculations. First, we introduce a Strutinsky-type approximation, in which quantum interference is treated as a correction to a smooth Thomas-Fermi description. For large irregular dots, we find that the second-order Strutinsky expressions have an

H. Dobler, D. Strauch

We investigate 1, 2, 3, and 4 monolayers of iron grown on the (001) surface of ZnSe using spin density functional theory, plane-wave expansion, and ultrasoft pseudopotentials. An ideal structure of the interface is plausible due to the very small lattice mismatch between both materials. However, we observe dramatic deviations from this idealized configuratio

Ellak Somfai, Nicholas R. Goold, Robin C. Ball, Jason P. DeVita

Random walkers absorbing on a boundary sample the Harmonic Measure linearly and independently: we discuss how the recurrence times between impacts enable non-linear moments of the measure to be estimated. From this we derive a new technique to simulate Dielectric Breakdown Model growth which is governed nonlinearly by the Harmonic Measure. Recurrence times a

Patrick Ilg, Iliya V. Karlin

A method for the combination of microscopic and macroscopic simulations is developed which is based on the invariance of the macroscopic relative to the microscopic dynamics. The method recognizes the onset and breakdown of the macroscopic description during the integration. We apply this method to the case of ferrofluid dynamics, where it switches between d

L. Palatella, P. Allegrini, P. Grigolini, V. Latora

With the help of the Diffusion Entropy technique we show the non-Poisson statistics of the distances between consecutive Omori's swarms of earthquakes. We give an analytical proof of the numerical results of an earlier paper [cond-mat/0212529, Mega et al., Phys. Rev. Lett. 90 (2003) 188501]

L. Harnau, S. Dietrich

The depletion potential between two hard spheres in a solvent of thin hard disclike platelets is investigated by using either the Derjaguin approximation or density functional theory. Particular attention is paid to the density dependence of the depletion potential. A second-order virial approximation is applied, which yields nearly exact results for the bul

Robert Spatschek

Nonequilibrium dynamics at interfaces is generally driven by a chemical potential. Here we demonstrate a generic technique to derive the basic equations of motion, boundary conditions and the chemical potential in a consistent way from fundamental variational principles. As a particular example, we consider a solid surface with elastodynamic effects, togethe

Jordi Molins, Eduard Vives

Within the framework of maximum entropy principle we show that the finite-size long-range Ising model is the adequate model for the description of homogeneous credit portfolios and the computation of credit risk when default correlations between the borrowers are included. The exact analysis of the model suggest that when the correlation increases a first-or

T. E. Humphrey, H. Linke

Conventional thermionic power generators and refrigerators utilize a barrier in the direction of transport to selectively transmit high-energy electrons. Here we show that the energy spectrum of electrons transmitted in this way is not optimal, and we derive the ideal energy spectrum for operation in the maximum power regime. By using suitable energy filters

Robert S. Whitney, Yuriy Makhlin, Alexander Shnirman, Yuval Gefen

We discuss the concept of the Berry phase in a dissipative system. We show that one can identify a Berry phase in a weakly-dissipative system and find the respective correction to this quantity, induced by the environment. This correction is expressed in terms of the symmetrized noise power and is therefore insensitive to the nature of the noise representing

I. Vekhter, A. V. Chubukov

We consider a two dimensional itinerant antiferromagnet near a quantum critical point. We show that, contrary to conventional wisdom, fermionic excitations in the ordered state are not the usual Fermi liquid quasiparticles. Instead, down to very low frequencies, the fermionic self energy varies as $ω^{2/3}$. This non-Fermi liquid behavior originates in the c

Serguei Brazovskii

Mysterious high temperature structureless transitions in (TMTTF)2X compounds have been discovered in mid 80's (Coulon, Lawersanne,vet al), but left unexplained and abandoned, together with other warnings from structural effects (Moret, Pouget, et al), with dramatic consequences for the whole field. Recently their nature has been identified as the ferroel

P. Süle

The 2D pair-condensate is characterized by a fluctuating chiral charge ordered state with a "checkerboard" pattern in the CuO_2 planes and with an alternating supermodulation along the c-axis in such a way that the adjacent layers are mirror images of one anothers electronic state. Planar chiral order is revealed with a recent circular dichroism (CD)

Arnab Chatterjee, Bikas K. Chakrabarti

The dynamic magnetization-reversal phenomena in the Ising model under a finite-duration external magnetic field competing with the existing order for $T<T_c^0$ has been discussed. The nature of the phase boundary has been estimated from the mean-field equation of motion. The susceptibility and relaxation time diverge at the MF phase boundary. A Monte Carlo s

Ewan M. Wright, Nikolay I. Zheludev

We elucidate the physical mechanisms by which electromagnetic excitations in planar chiral waveguides exhibit broken time reversal and parity symmetries as recently observed in metallic nanostructures (Phys. Rev. Lett. 91, 247404 (2003)). Furthermore, we show that concomitant with these broken symmetries the electromagnetic excitations can acquire fractional

Heiko Bauke, Stephan Mertens

Tossing a coin is the most elementary Monte Carlo experiment. In a computer the coin is replaced by a pseudo random number generator. It can be shown analytically and by exact enumerations that popular random number generators are not capable of imitating a fair coin: pseudo random coins show more heads than tails. This bias explains the empirically observed

Kurt L. Adelberger, Charles C. Steidel, Alice E. Shapley, Matthew P. Hunt

Few galaxies have been found between the redshift ranges z < ~1 probed by magnitude-limited surveys and z > ~3 probed by Lyman-break surveys. Comparison of galaxy samples at lower and higher redshift suggests that large numbers of stars were born and the Hubble sequence began to take shape at the intermediate redshifts 1<z<3, but observational challenges hav

Michael M. Shara, David R. Zurek, Edward A. Baltz, Tod R. Lauer

Only one certain classical nova eruption has ever been detected inside a globular cluster - nova 1860 A.D. (T Sco) in M80. During a survey of M87 we have detected an erupting star coincident (to within 0.08 pixels) with a globular cluster of that giant elliptical galaxy. We are able to discount variables in the foreground or background of M87. The light curv

Brad Hansen, Harvey Richer, Greg Fahlman, Peter Stetson

We investigate in detail the white dwarf cooling sequence of the globular cluster Messier 4. In particular we study the influence of various systematic uncertainties, both observational and theoretical, on the determination of the cluster age from the white dwarf cooling sequence. These include uncertainties in the distance to the cluster and the extinction

Scott Croom, David Schade, Brian Boyle, Tom Shanks

We present results of a Gemini adaptive optics (AO) imaging program to investigate the host galaxies of typical QSOs at z~2. Our aim is to study the host galaxies of typical, L*_qso QSOs at the epoch of peak QSO and star formation activity. The large database of faint QSOs provided by the 2dF QSO Redshift Survey allows us to select a sample of QSOs at z=1.75

H. B. Richer, G. G. Fahlman, J. Brewer, S. Davis

This paper presents new results from a photometric study of the main-sequence stars in M4, the closest globular cluster to the sun. Multi-field, multi-epoch observations at approximately 1, 2, and 6 core-radii were obtained with the WFPC2 camera on the HST. The multi-epoch observations allowed us to clean the data on the basis of proper motion. In all the fi

C. C. Steidel, A. E. Shapley, M. Pettini, K. L. Adelberger

We present the first results of a large-scale survey, using the UV/blue sensitive LRIS-B spectrograph on the Keck I telescope, of galaxies in the redshift interval 1.4<z<2.5, often called the `redshift desert&#39; because of historical difficulties in spectroscopically identifying galaxies in that range. We introduce two samples of star forming galaxies, `BX

Sean N. Raymond, Oliver J. Fraser, Arti Garg, Suzanne L. Hawley

We present a detailed observational strategy for finding Near Earth Objects (NEOs) with the Sloan Digital Sky Survey (SDSS) telescope. We investigate strategies in normal, unbinned mode as well as binning the CCDs 2x2 or 3x3, which affects the sky coverage rate and the limiting apparent magnitude. We present results from 1 month, 3 year and 10 year simulatio

Lauren A. MacArthur, Stephane Courteau, Eric Bell, Jon Holtzman

(Abridged) We investigate optical and near-IR color gradients in a sample of 172 low-inclination galaxies spanning Hubble types S0--Irr. The colors are compared to stellar population synthesis models from which luminosity-weighted average ages and metallicities are determined. We explore the effects of different underlying star formation histories and additi

M. Vestergaard

The applicability and apparent uncertainties of the techniques currently available for measuring or estimating black-hole masses in AGNs are briefly summarized.