September 2001 arXiv papers — page 12

Ariel Caticha

I explore the possibility that the laws of physics might be laws of inference rather than laws of nature. What sort of dynamics can one derive from well-established rules of inference? Specifically, I ask: Given relevant information codified in the initial and the final states, what trajectory is the system expected to follow? The answer follows from a princ

O. A. Khrustalev, M. V. Tchitchikina

Quantization of gravitational field in the neighbourhood of exact solution of Einstein equation is considered. The method of Bogoliubov group variables is used.

O. A. Khrustalev, M. V. Tchitchikina

Quantization of gravitational field in the neighbourhood of arbitrary nontrivial solution of Einstein equations is considered, the 2nd order of perturbation theory is calculated. The expression for quantum corrections of the field operator and explicit view of Hamiltonian are represented.

Hideo Kodama

The structure of phase space is determined for spatially compact and locally homogeneous universe models with fluid. Analysis covers models with all possible space topologies except for those covered by S^3, H^3 or S^2xR which have no moduli freedom. We show that space topology significantly affects the number of dynamical degrees of freedom of the system. I

Thibault Damour

The Equivalence Principle (EP) is not one of the ``universal'' principles of physics (like the Action Principle). It is a heuristic hypothesis which was introduced by Einstein in 1907, and used by him to construct his theory of General Relativity. In modern language, the (Einsteinian) EP consists in assuming that the only long-range field with gravit

Rob Frieden

A dichotomy in regulatory treatment and corporate cultures exists between Internet Service Providers (ISPs) and telecommunication carriers. Telephone company executives (Bell Heads) may resent regulation, but they accept their fate and work creatively to exploit anomalies and opportunities to secure a regulation-conferred competitive advantage. Most ISP exec

Ingo Kreuz, Dieter Roller

In order to solve complex configuration tasks in technical domains, various knowledge based methods have been developed. However their applicability is often unsuccessful due to their low efficiency. One of the reasons for this is that (parts of the) problems have to be solved again and again, instead of being "learnt" from preceding processes. Howev

Eneko Agirre, Olatz Ansa, Eduard Hovy, David Martinez

This paper explores the possibility of enriching the content of existing ontologies. The overall goal is to overcome the lack of topical links among concepts in WordNet. Each concept is to be associated to a topic signature, i.e., a set of related words with associated weights. The signatures can be automatically constructed from the WWW or from sense-tagged

W. C. Wu, R. Joynt

We calculate the ultrasonic absorption and the thermal conductivity in the superconducting state of UPt$_{3}$ as functions of temperature and direction of propagation and polarization. Two leading candidates for the superconducting order parameter are considered: the $E_{1g}$ and $E_{2u}$ representations. Both can fit the data except for the ultrasonic absor

G. Zarand, F. Pazmandi, K. F. Pal, G. T. Zimanyi

We propose a new optimization method based on a demagnetization procedure well known in magnetism. We show how this procedure can be applied as a general tool to search for optimal solutions in any system where the configuration space is endowed with a suitable `distance'. We test the new algorithm on frustrated magnetic models and the traveling salesman

Igor S. Aranson, Lev S. Tsimring

A continuum theory of partially fluidized granular flows is developed. The theory is based on a combination of the equations for the flow velocity and shear stresses coupled with the order parameter equation which describes the transition between flowing and static components of the granular system. We apply this theory to several important granular problems

Fulvio Baldovin

For a paradigmatic case, the standard map, we discuss how the statistical description of the approach to equilibrium is related to the sensitivity to the initial conditions of the system. Using a numerical analysis we present an anomalous scenario that may give some insight on the foundations of the Tsallis' statistical mechanics.

Frederic Caupin, Sebastien Balibar, Humphrey J. Maris

Experimental investigation of cavitation in liquid helium 3 has revealed a singular behaviour in the degenerate region at low temperature. As the temperature decreases below 80 mK, the cavitation pressure becomes significantly more negative. To investigate this, we have extrapolated the Fermi parameters in the negative pressure region. This allowed us to cal

R. L. Willett, K. W. West, L. N. Pfeiffer

Using small wavelength surface acoustic waves (SAW) on ultra-high mobility heterostructures, Fermi surface properties are detected at 5/2 filling factor at temperatures higher than those at which the quantum Hall state forms. An enhanced conductivity is observed at 5/2 by employing sub 0.5 micron wavelength SAW, indicating a quasiparticle mean-free-path subs

R. L. Willett, K. W. West, L. N. Pfeiffer

To establish the presence and orientation of the proposed striped phase in ultra-high mobility 2D electron systems at filling factor 9/2, current path transport properties are determined by varying the separation and allignment of current and voltage contacts. Contacts alligned orthogonal to the proposed intrinsic striped phase produce voltages consistent wi

Pierre-Henri Chavanis

We complete previous investigations on the statistics of velocity fluctuations arising from a random distribution of point vortices in two-dimensional hydrodynamics. We show that, on a statistical sense, the velocity created by a point vortex is shielded by cooperative effects on a distance $Λ\sim n^{-1/2}$, the inter-vortex separation. For $R\gg Λ$, the ``e

A. T. Costa, R. B. Muniz

We show that electrical current flowing through nanowires made of ferromagnetic disordered alloys can become highly spin polarized.

Frederic Caupin, Sebastien Balibar

Recent experiments have suggested that, at low enough temperature, the homogeneous nucleation of bubbles occurs in liquid helium near the calculated spinodal limit. This was done in pure superfluid helium 4 and in pure normal liquid helium 3. However, in such experiments, where the negative pressure is produced by focusing an acoustic wave in the bulk liquid

Frederic Caupin, Sebastien Balibar, Humphrey J Maris

We propose that the liquid-gas spinodal line of helium 3 reaches a minimum at 0.4 K. This feature is supported by our cavitation measurements. We also show that it is consistent with extrapolations of sound velocity measurements. Speedy [J. Phys. Chem. 86, 3002 (1982)] previously proposed this peculiar behavior for the spinodal of water and related it to a c

V. A. Ivanov, M. van den Broek, F. M. Peeters

MgB$(p^{n_σ}p^{n_π})_{2}$ is classified as a system with strongly interacting $σ$-electrons and non-correlated $π$-electrons of boron ions. The kinematic and Coulomb interaction V between the orbitally degenerated $σ$-electrons provide the superconducting state with an anisotropic gap of s*-wave symmetry. The critical temperature $T_c$ has a non-monotonic de

Frithjof B. Anders

An unconventional superconducting phase is explored developing out of a non Fermi-liquid phase of the two-channel Anderson lattice model. It is characterized by a composite order parameter comprising of a local spin or orbital degree of freedom bound to triplet Cooper pairs with an isotropic and a nearest neighbour form factor. The superconducting transition

M. G. A. Crawford, P. W. Brouwer

We calculate the density P(τ) of the eigenvalues of the Wigner-Smith time delay matrix for two-dimensional rectangular and circular billiards with one opening. For long times, the density of these so-called "proper delay times" decays algebraically, in contradistinction to chaotic quantum billiards for which P(τ) exhibits a long-time cut-off.

M. Keller, W. Metzner, U. Schollwoeck

We analyze the normal phase of the attractive Hubbard model within dynamical mean-field-theory. We present results for the pair-density, the spin-susceptibility, the specific heat, the momentum distribution, and for the quasiparticle weight. At weak coupling the low-temperature behavior of all quantities is consistent with Fermi liquid theory. At strong coup

Laurent Proville, S. Aubry

A variational approach is proposed to determine some properties of the adiabatic Holstein-Hubbard model which describes the interactions between a static atomic lattice and an assembly of fermionic charge carriers. The sum of the electronic energy and the lattice elastic energy is proved to have minima with a polaron structure in a certain domain of the phas

Daniel Duque

M. Girardi and W. Figueiredo have proposed a simple model of aggregation in one dimension to mimic the self-assembly of amphiphiles in aqueous solution [Phys. Rev. E 62, 8344 (2000)]. We point out that interesting results can be obtained if a different set of interactions is considered, instead of their choice (the s=1 Ising model).

Karlo Penc, B. Sriram Shastry

We study the exact one electron propagator and spectral function of a solvable model of interacting electrons due to Schulz and Shastry. The solution previously found for the energies and wave functions is extended to give the spectral functions, which turn out to be computable, interesting and non trivial. They provide one of the few examples of cases where

R. Egger, A. O. Gogolin

Carbon nanotubes provide a new class of molecular wires that display new and exciting mesoscopic transport properties. We provide a detailed theoretical description for transport in multi-wall nanotubes, where both disorder and strong interactions are important. The interplay of both aspects leads to a particularly effective intrinsic Coulomb blockade for tu

F. Renzoni, T. Brandes

We describe a novel mechanism for charge pumping through tunnel-coupled quantum dots in the regime of strong Coulomb blockade. The quantum state of an additional electron within the structure is steered by changing the tunneling couplings between neighbouring dots. Appropriate tailoring of the interdot tunneling rates allows to design the instantaneous eigen

I. Shtrichman, C. Metzner, B. D. Gerardot, W. V. Schoenfeld

We study the electronic coupling between two vertically stacked InAs quantum dots, which are embedded in the center of a n-i-n structure. We use a micro-photoluminescence setup to optically isolate a single quantum dot pair and measure the time-averaged photoluminescence under an applied vertical electric field. We find that field tunable coupling between ex

M. H. S. Amin, A. N. Omelyanchouk, A. M. Zagoskin

We investigate nonlocal coherent transport in ballistic four-terminal Josephson structures (where bulk superconductors (terminals) are connected through a clean normal layer, e.g., a two-dimensional electron gas). Coherent anisotropic superposition of macroscopic wave functions of the superconductors in the normal region produces phase slip lines (2D analogs

Yuqing Wang, Z. D. Wang, Y. -X. Li, X. Pei

Synchronization is studied in a spatially-distributed network of weekly-coupled, excitatory neurons of Hodgkin-Huxley type. All neurons are coupled to each other synaptically with a fixed time delay and a coupling strength inversely proportional to the distance between two neurons. We found that a robust, noise-resistant phase clustering state occurred regar

D. M. Edwards, A. C. M. Green

An introduction is given to the many-body coherent potential approximation (CPA) for the double-exchange (DE) model and the Holstein-DE model, the latter including coupling of the electrons to local phonons as well as to local spins. It is shown how the method can treat the local spins and phonons quantum-mechanically and how it is equivalent to dynamical me

Fulvio Baldovin, Constantino Tsallis, Bruno Schulze

The standard map is a paradigmatic one-parameter (noted $a$) two-dimensional conservative map which displays both chaotic and regular regions. This map becomes integrable for $a=0$. For $a \ne 0$ it can be numerically shown that the usual, Boltzmann-Gibbs entropy $S_1(t)=-\sum_{i} p_i(t)\ln{p_i(t)}$ exhibits a {\it linear} time evolution whose slope hopefull

Anca Constantin, Joseph C. Shields, Fred Hamann, Craig B. Foltz

We present results of a program of high signal-to-noise spectroscopy for 44 QSOs at redshifts > 4 using the MMT and Keck observatories. The quasar spectra cover 1100 -- 1700 A in the rest frame for sources spanning a luminosity range of approximately 2 orders of magnitude. Comparisons between these data and spectra of lower redshift quasars reveal a high deg

G. Duchene, T. Simon, J. Eisloffel, J. Bouvier

We have searched for visual binaries with projected separations in the range 200-3000 AU (0.1"-1.5") among a sample of 96 stars in the massive young NGC 6611 cluster, 60 of them being subsequently identified as high probability cluster members of mainly OB spectral type. This is the first visual binary survey among such a large and homogeneous sample

H. M. Antia, S. Basu, F. Hill, R. Howe

We study the variation of the frequency splitting coefficients describing the solar asphericity in both GONG and MDI data, and use these data to investigate temporal sound-speed variations as a function of both depth and latitude during the period from 1995-2000 and a little beyond. The temporal variations in even splitting coefficients are found to be corre

Joseph Silk

The formation of supermassive black holes (SMBH) is intimately related to galaxy formation, although precisely how remains a mystery. I speculate that formation of, and feedback from, SMBH may alleviate problems that have arisen in our understanding of the cores of dark halos of galaxies.

G. Taffoni, P. Monaco, T. Theuns

We study the ability of PINOCCHIO (PINpointing Orbit-Crossing Collapsed HIerarchical Objects) to predict the merging histories of dark matter (DM) haloes, comparing the PINOCCHIO predictions with the results of two large N-body simulations run from the same set of initial conditions. We focus our attention on quantities most relevant to galaxy formation and

P. Monaco, T. Theuns, G. Taffoni, F. Governato

We present a new algorithm (PINOCCHIO, PINpointing Orbit-Crossing Collapsed HIerarchical objects) to predict accurately the formation and evolution of individual dark matter haloes in a given realization of an initial linear density field. Compared with the halo population formed in a large (360^3 particles) collisionless simulation of a CDM universe, our me

J. C. Jackson, Marina Dodgson

We determine cosmological and evolutionary parameters from the 3CR K-band Hubble diagram and K-band number counts, assuming that the galaxies in question undergo pure luminosity evolution. Separately the two data sets are highly degenerate with respect to choice of cosmological and evolutionary parameters, but in combination the degeneracy is resolved. Of mo

Gary Bernstein

The familiar tools of Fourier analysis and Fisher matrices are applied to derive the uncertainties on photometric, astrometric, and weak-lensing measurements of stars and galaxies in real astronomical images. Many effects or functions that are ignored in basic exposure-time calculators can be included in this framework: pixels of size comparable to the stell

Todd A. Boroson

Recent studies of black holes in the nuclei of both active and normal galaxies have yielded relationships that permit a physical interpretation of the principal components of the spectra of QSOs. It is shown that principal component (or eigenvector) 1 (PC1) is driven predominantly by L/L{Edd}, and principal component 2 (PC2) is driven by luminosity or accret

H. Bravo-Alfaro, V. Cayatte, J. H. van Gorkom, C. Balkowski

In the first paper of this series we used HI observations of the 19 brightest spirals in Coma to analyze the dynamical state of the cluster. In this paper we present the detailed HI distribution and kinematics of the spirals that were detected in HI, and radio continuum data for a sample of star forming and post starburst galaxies in Coma. We discuss the imp

E. Romano-Diaz, E. Branchini, R. van de Weygaert, .

We assess the extent to which the flux-limited PSCz redshift sample is capable of accounting for the major share of mass concentrations inducing the external tidal forces affecting the peculiar velocities within the Local Supercluster (LS). The investigation is based upon a comparison of the ``true'' velocities in 2 large N-body simulations and their

Ehud Behar, Masao Sako, Steven M. Kahn

A full set of calculations is presented for inner-shell n = 2 to 3 photoexcitation of the 16 iron charge states: Fe I through Fe XVI. The blend of the numerous absorption lines arising from these excitations (mainly 2p - 3d) forms an unresolved transition array (UTA), which has been recently identified as a prominent feature between 16 - 17 Åin the soft X-ra

C. R. Benn, M. Vigotti, M. Pedani, J. Holt

In a pilot search for high-redshift radio QSOs, we have obtained spectra of 55 FIRST sources (S(1.4GHz) > 1 mJy) with very red (O-E > 3) starlike optical identifications. 10 of the candidates are QSOs with redshifts 3.6 < z < 4.4 (4 previously known), six with z > 4. The remaining 45 candidates comprise: a z = 2.6 BAL QSO; 3 low-redshift galaxies with narrow

M. Haverkorn, P. Katgert, A. G. de Bruyn

We present multi-frequency polarization observations of the diffuse radio synchrotron background modulated by Faraday rotation. No total intensity is observed, indicating that total intensity does not vary on scales below approximately a degree. However, polarized intensity and polarization angle show abundant small-scale structure due to Faraday rotation in

D. Steeghs, T. Marsh, C. Knigge, P. Maxted

We present the first detection of the mass donor star in the cataclysmic variable WZ Sge. Phase resolved spectroscopy reveals narrow Balmer emission components from the irradiated secondary star during the 2001 outburst. Its radial velocity curve indicates a systemic velocity of -72 +/- 3 km/s and an apparent velocity amplitude of K_2_app=493 +/- 10 km/s. Do

W. V. Dixon, J. Dupuis, M. Hurwitz

The Berkeley Extreme and Far-Ultraviolet Spectrometer (BEFS) flew as part of the ORFEUS telescope on the ORFEUS-SPAS I and II space-shuttle missions in 1993 and 1996, respectively. The data obtained by this instrument have now entered the public domain. To facilitate their use by the astronomical community, we have re-extracted and re-calibrated both data se

N. Dauphas, B. Marty

Noble metals and gases are very sensitive to the late accretion to the Earth of asteroids and comets. We present mass balance arguments based on these elements that indicate that 0.7E22-2.7E22 kg of extraterrestrial bodies struck the Earth after core formation and that comets comprised less than 1E-5 by mass of the impacting population. These results imply t

Katsuji Koyama

This paper reviews the Chandra deep exposure observations of star forming regions, rho-Ophiuchi, Orion Molecular Clouds 2 and 3, Sagittarius B2 and Monoceros R2. The results are; (1) class I protostars are found to exhibit higher temperature plasma than those of T Tauri stars, (2) heavily absorbed X-rays are discovered from the candidates of class 0 protosta

S. Zieba, J. Maslowski, A. Michalec, A. Kulak

Three types of observations: the daily values of the solar radio flux at 7 frequencies, the daily international sunspot number and the daily Stanford mean solar magnetic field were processed in order to find all the periodicities hidden in the data. Using a new approach to the radio data, two time series were obtained for each frequency examined, one more se

S. Cristiani, S. Bianchi, S. D&#39;Odorico, T. -S. Kim

A sample of 8 QSOs with 1.7 < z_em < 3.7 has been observed with VLT/UVES at a typical resolution 45000 and S/N~40-50. Thanks to the two-arm design of the spectrograph, a remarkable efficiency has been achieved below 400nm and above 800nm, which translates immediately in the possibility of obtaining new results, especially at z<2.5. We report here new insight

Sam Phillips, Philipp Podsiadlowski

We present a method for the calculation of the effects of external irradiation on the geometrical shape of the secondary in a close binary containing a compact star, the source of the radiation, and a normal companion star, where we include the possibility of shadowing by an accretion disc. The model is based on a simple modification of the standard Roche bi

Jongsoo Kim, Dongsu Ryu

The Parker instability is considered to play important roles in the evolution of the interstellar medium. Most studies on the development of the instability so far have been based on an initial equilibrium system with a uniform magnetic field. However, the Galactic magnetic field possesses a random component in addition to the mean uniform component, with co

A. Zezas, G. Fabbiano, A. Prestwich, M. Ward

We present Chandra observations of two star-forming galaxies (M82 and the Antennae) and three starburst/AGN composite galaxies (NGC1808, NGC6240, NGC7331). In both star-forming galaxies we detect a large number of sources with diverse properties. Some of them can be identified as X-ray binaries, based on their variability and spectra. However, there is a sig

Frieder Kleefeld, Eef van Beveren, George Rupp, Michael D. Scadron

The assignments of the isoscalar scalar mesons f0(980), f0(1370), and f0(1500) in terms of their qqbar substructure is still a matter of heated dispute. Here we employ the weak and electromagnetic decays D(s)(+) to f0+pi(+) and f0 two-photon decays, respectively, to identify the f0(980) and f0(1500) as mostly ssbar, and the f0(1370) as dominantly nonstrange,

Keith Kastella, Richard Freeling

In the multitarget Grover algorithm, we are given an unstructured N-element list of objects S_i containing a T-element subset tau and function f, called an oracle, such that f(S_i)=1 if S_i is in tau, otherwise f(S_i) = 0. By using quantum parallelism, an element of tau can be retrieved in O(sqrt(N/T)) steps, compared to O(N/T) for any classical algorithm. I

G. M. Kavoulakis, S. M. Reimann, B. Mottelson

Recently Liu et al. [PRL 87, 030404 (2001)] examined the lowest state of a weakly-interacting Bose-Einstein condensate. In addition to other interesting results, using the method of the pair correlation function, they questioned the validity of the mean-field picture of the formation of vortices and stated that the vortices are generated at the center of the

Subir Sachdev

We discuss the possibility of spin glass order in the vicinity of the unexpected metallic state of the two-dimensional electron gas in zero applied magnetic field. An average ferromagnetic moment may also be present, and the spin glass order then resides in the plane orthogonal to the ferromagnetic moment. We argue that a quantum transition involving the des

Louis-Pierre Arguin, Yvan Saint-Aubin

We introduce three non-local observables for the two-dimensional Ising model. At criticality, conformal field theory may be used to obtain theoretical predictions for their behavior. These formulae are explicit enough to show that their asymptotics are described by highest weights $h_{pq}$ from the Kac table for c=1/2 distinct from those of the three unitary

Vittorio Barone Adesi, Sergio Zerbini

A new formula relating the analytic continuation of the Hurwitz zeta function to the Euler gamma function and a polylogarithmic function is presented. In particular, the values of the first derivative of the real part of the analytic continuation of the Hurwitz zeta function for even negative integers and the imaginary one for odd negative integers are expli

Brian C. Hall, Jeffrey J. Mitchell

We describe a family of coherent states and an associated resolution of the identity for a quantum particle whose classical configuration space is the d-dimensional sphere S^d. The coherent states are labeled by points in the associated phase space T*(S^d). These coherent states are NOT of Perelomov type but rather are constructed as the eigenvectors of suit

Pierre Sikivie

The late infall of cold dark matter onto our galaxy produces discrete flows and caustics in its halo. The recently discovered ring of stars near galactocentric distance 20 kpc and a series of sharp rises in the Milky Way rotation curve are interpreted as due to the presence of caustic rings of dark matter in the galactic plane. Their locations are consistent

Frédéric Grosshans, Philippe Grangier

We propose several methods for quantum key distribution (QKD) based upon the generation and transmission of random distributions of coherent or squeezed states, and we show that they are are secure against individual eavesdropping attacks. These protocols require that the transmission of the optical line between Alice and Bob is larger than 50 %, but they do

Claudio Meneghini

This thesis is concerned with extending the idea of geodesic completeness from pseudo-Riemannian to complex geometry: we take, however a completely holomorphicpoint of view; that is to say, a &#39;metric&#39; will be a (meromorphic) symmetric section of the twice covariant holomorphic tensor bundle. We shall hint at the need of reformulating some aspects of

Alon E. Faraggi, Marc Thormeier

Grand unification, and its incarnation in the form of heterotic-string unification, are the only extensions of the Standard Model that are rooted in the structure of the Standard Model itself. In this context, it was proposed that the exclusiveness of proton stability and suppression of neutrino masses necessitates the existence of an additional U(1)_Z&#39;

C. Bartocci, U. Bruzzo, D. Hernandez Ruiperez, J. M. Muñoz Porras

We consider a relative Fourier-Mukai transform defined on elliptic fibrations over an arbitrary normal base scheme. This is used to construct relative Atiyah sheaves and generalize Atiyah&#39;s and Tu&#39;s results about semistable sheaves over elliptic curves to the case of elliptic fibrations. Moreover we show that this transform preserves relative (semi)s

R. Aurich, F. Steiner

Dark energy models due to a slowly evolving scalar (quintessence) field $ϕ$ are studied for various potentials $V(ϕ)$ in a universe with negative curvature. The potentials differ in whether they possess a minimum at $ϕ=0$ or are monotonically declining, i.e. have a minimum at infinity. The angular power spectrum $C_l$ of the cosmic microwave background (CMB)

Michal Chodorowski, Pawel Ciecielag

In maximum-likelihood analyses of the Local Group (LG) acceleration, the object describing nonlinear effects is the coherence function (CF), i.e. the cross-correlation coefficient of the Fourier modes of the velocity and gravity fields. We study the CF both analytically, using perturbation theory, and numerically, using a hydrodynamic code. The dependence of

Stanislav Smirnov, Wendelin Werner

We show how to combine Kesten&#39;s scaling relations, the determination of critical exponents associated to the stochastic Loewner evolution process by Lawler, Schramm, and Werner, and Smirnov&#39;s proof of Cardy&#39;s formula, in order to determine the existence and value of critical exponents associated to percolation on the triangular lattice.

D. DeMille

We propose a novel physical realization of a quantum computer. The qubits are electric dipole moments of ultracold diatomic molecules, oriented along or against an external electric field. Individual molecules are held in a 1-D trap array, with an electric field gradient allowing spectroscopic addressing of each site. Bits are coupled via the electric dipole

Lukas Kurtz, Herschel Rabitz, Regina de Vivie-Riedle

A novel algorithm was recently presented to utilize emerging time dependent probability density data to extract molecular potential energy surfaces. This paper builds on the previous work and seeks to enhance the capabilities of the extraction algorithm: An improved method of removing the generally ill-posed nature of the inverse problem is introduced via an

A. Helmstetter, D. Sornette

We present an analytical solution and numerical tests of the epidemic-type aftershock (ETAS) model for aftershocks, which describes foreshocks, aftershocks and mainshocks on the same footing. The occurrence rate of aftershocks triggered by a single mainshock decreases with the time from the mainshock according to the modified Omori law K/(t+c)^p with p=1+the

H. Huffel

We perform the Batalin-Vilkovisky quantization of Yang-Mills theory on a 2-point space, discussing the formulation of Connes-Lott as well as Connes&#39; real spectral triple approach. Despite of the model&#39;s apparent simplicity the gauge structure reveals infinite reducibility and the gauge fixing is afflicted with the Gribov problem.

C. Garcia-Recio, J. Nieves, E. Oset, A. Ramos

A microscopic optical potential based on a chiral model is used as a starting point for studying kaonic atoms levels. We add to this potential a phenomenological part fitted to the experimentally known shifts and widths of kaonic levels. This fitted potential is used to predict deeply bound atomic levels, as well as nuclear levels. Comparison with the predic

Yu. A. Simonov

General solution of RG equations in the framework of background perturbation theory is written down in the large N_c limit. A simplified (model) approximation to the general solution is suggested which allows to write beta(alpha) and alpha(beta) to any loop order. The resulting alpha_B(Q^2) coincides asymptotically at large $|Q^2|$ with standard (free) alpha

J. L. Chkareuli, C. D. Froggatt, H. B. Nielsen

We argue that flavour mixing, both in the quark and lepton sector, follows the minimal mixing pattern, according to which the whole of this mixing is basically determined by the physical mass generation for the first family of fermions. So, in the chiral symmetry limit when the masses of the lightest ($u$ and $d$) quarks vanish, all the quark mixing angles v

Rong-Gen Cai

We study thermodynamic properties and phase structures of topological black holes in Einstein theory with a Gauss-Bonnet term and a negative cosmological constant. The event horizon of these topological black holes can be a hypersurface with positive, zero or negative constant curvature. When the horizon is a zero curvature hypersurface, the thermodynamic pr

V. V. Pashkevich, P. Meier, M. Brack, A. V. Unzhakova

We use a perturbative semiclassical trace formula to calculate the three lowest-order multipole (quadrupole $\eps_2$, octupole $\eps_3$, and hexadecapole $\eps_4$) deformations of simple metal clusters with $90 \le N \le 550$ atoms in their ground states. The self-consistent mean field of the valence electrons is modeled by an axially deformed cavity and the

D. Pini, A. Parola, L. Reatto

We study a simple modification of the optimized random phase approximation (ORPA) aimed at improving the performance of the theory for interactions with a narrow attractive well by taking into account contributions to the direct correlation function non-linear in the interaction. The theory is applied to a hard-core Yukawa and a square-well potential. Result

K. Abe

We report a search for the flavor-changing neutral current decay $B \to K^{(*)} \ell^{+} \ell^{-}$ using a 29.1 fb${}^{-1}$ data sample accumulated at the $Υ(4S)$ resonance with the Belle detector at the KEKB $e^{+}e^{-}$ storage ring. We observe the decay process $B\to K\ell^+\ell^- (\ell = e, μ)$, for the first time, with a branching fraction of ${\cal B}(

Ayman F. Abouraddy, Bahaa E. A. Saleh, Alexander V. Sergienko, Malvin C. Teich

We demonstrate that any pure bipartite state of two qubits may be decomposed into a superposition of a maximally entangled state and an orthogonal factorizable one. Although there are many such decompositions, the weights of the two superposed states are, remarkably, unique. We propose a measure of entanglement based on this decomposition. We also demonstrat

Pawel Wocjan, Martin Roetteler, Dominik Janzing, Thomas Beth

We address the problem of simulating pair-interaction Hamiltonians in n node quantum networks where the subsystems have arbitrary, possibly different, dimensions. We show that any pair-interaction can be used to simulate any other by applying sequences of appropriate local control sequences. Efficient schemes for decoupling and time reversal can be construct

S Codriansky, S Salamo

As a result of the so(2,1) of the hypergeometric Natanzon potential a set of potentials related to the given one is determined. The set arises as a result of the action of the so(2,1) generators.

Akira Shimizu, Takayuki Miyadera, Akihisa Ukena

In quantum systems of a macroscopic size V, such as interacting many particles and quantum computers with many qubits, there exist pure states such that fluctuations of some intensive operator A is anomalously large, <δA^2> = O(V^0), which is much larger than that assumed in thermodynamics, <δA^2> = O(1/V). By making full use of the locality, we show, starti

H. A. Kastrup

A typical classical interference pattern of two waves with intensities I_1, I_2 and relative phase phi = phi_2-phi_1 may be characterized by the 3 observables p = sqrt{I_1 I_2}, p cosϕand -p sinϕ. They are, e.g. the starting point for the semi-classical operational approach by Noh, Fougeres and Mandel (NFM) to the old and notorious phase problem in quantum o

R. Srikanth

Wheeler&#39;s delayed choice experiment, a well known manifestation of the complementarity principle, has proved somewhat difficult to physically interpret. We show that, restated in quantum field theoretic language, the experiment submits to a simple explanation: that wave- or particle-nature is imposed not at the slit plane but at the detector system. The

W. Krause, A. V. Korol, A. V. Solov&#39;yov, W. Greiner

This paper discusses the undulator radiation emitted by high-energy positrons during planar channeling in periodically bent crystals. We demonstrate that the construction of the undulator for positrons with energies of 10 GeV and above is only possible if one takes into account the radiative energy losses. The frequency of the undulator radiation depends on

A. V. Korol, A. V. Solov&#39;yov, W. Greiner

This paper is devoted to a detailed analysis of the new type of the undulator radiation generated by an ultra-relativistic charged particle channeling along a crystal plane, which is periodically bent by a transverse acoustic wave, as well as to the conditions limiting the observation of this phenomenon. This mechanism makes feasible the generation of electr

W. Krause, A. V. Korol, A. V. Solov&#39;yov, W. Greiner

This paper discusses the undulator radiation emitted by high-energy positrons during planar channeling in periodically bent crystals. We demonstrate that the construction of the undulator for positrons with energies of 10 GeV and above is only possible if one takes into account the radiative energy losses. The frequency of the undulator radiation depends on

W. Krause, A. V. Korol, A. V. Solov&#39;yov, W. Greiner

We present the results of numerical calculations of the channelling and undulator radiation generated by an ultra-relativistic positron channelling along a crystal plane, which is periodically bent. The bending might be due either to the propagation of a transverse acoustic wave through the crystal, or due to the static strain as it occurs in superlattices.

A. V. Korol, W. Krause, A. V. Solov&#39;yov, W. Greiner

We discuss radiation generated by positrons channeling in a crystalline undulator. The undulator is produced by periodically bending a single crystal with an amplitude much larger than the interplanar spacing. Different approaches for bending the crystal are described and the restrictions on the parameters of the bending are established. We present the resul

A. V. Korol, A. V. Solov&#39;yov, W. Greiner

We investigate, both analytically and numerically, the influence of the dechanneling process on the parameters of undulator radiation generated by ultra-relativistic positron channelling along a crystal plane, which is periodically bent. The bending might be due either to the propagation of a transverse acoustic wave through the crystal, or due to the static

W. Krause, A. V. Korol, A. V. Solov'yov, W. Greiner

We discuss the radiation generated by positrons channeling in a crystalline undulator. The undulator is produced by periodically bending a single crystal with an amplitude much larger than the interplanar spacing. Different approaches for bending the crystal are described and the restrictions on the parameters of the bending are discussed. We also present nu

A. V. Korol, A. V. Solov&#39;yov, W. Greiner

This paper is devoted to the investigation of the radiation energy losses of an ultra-relativistic charged particle channeling along a crystal plane which is periodically bent by a transverse acoustic wave. In such a system there are two essential mechanisms leading to the photon emission. The first one is the ordinary channeling radiation. This radiation is

A. V. Korol, A. V. Solov&#39;yov, W. Greiner

We suggest a new type of the undulator radiation which is generated by an ultra-relativistic particle channeled along a periodically bent crystallographic plane or axis. The electromagnetic radiation arises mainly due to the bending of the particle&#39;s trajectory, which follows the shape of the channel. The parameters of this undulator, which totally defin

A. D. Lahiff, I. R. Afnan

A covariant model of elastic pion-nucleon scattering based on the Bethe-Salpeter equation is presented. We obtain a good description of the S- and P-wave phase shifts up to 360 MeV laboratory energy. We also compare results from the K-matrix approach and several 3-dimensional quasipotential equations to the Bethe-Salpeter equation.

S. Ando, T. -S. Park, K. Kubodera, F. Myhrer

Muon capture on the deuteron is studied in heavy baryon chiral perturbation theory (HBChPT). It is found that by far the dominant contribution to $μd$ capture comes from a region of the final three-body phase-space in which the energy of the two neutrons is sufficiently small for HBChPT to be applicable. The single unknown low-energy constant having been fix

N. Kaiser, W. Weise

The role of chiral (pion) dynamics in nuclear matter is reviewed. Contributions to the energy per particle from one- and two-pion exchange are calculated systematically, and it is demonstrated that already at order $k^4_f$ in the Fermi momentum, two-pion exchange produces realistic nuclear binding together with very reasonable values for the compressibility