March 2001 arXiv papers — page 18

V. A. Dolgushev, S. L. Lyakhovich, A. A. Sharapov

The notion of the Wick star-product is covariantly introduced for a general symplectic manifold equipped with two transverse polarisations. Along the lines of Fedosov method, the explicit procedure is given to construct the Wick symbols on the manifold. The cohomological obstruction is identified to the equivalence between the Wick star-product and the Fedos

S. Gardner, Ulf-G. Meißner, G. Valencia

We consider what constraints unitarity and CPT invariance yield on the strong and electromagnetic phases entering K -> pi pi decay. In particular, we show that the relative size of the electromagnetically-induced changes in the I=0 and I=2 phase shifts in the two--pion final state do not depend on the explicit coupling to the pi^+ pi^- gamma channel. This de

T. Barnes

In this talk I give a short summary of the basics of conventional and exotic meson spectroscopy, and consider in particular those issues in the charmonium and charmonium hybrid sectors which can be addressed by a future antiproton facility at GSI.

M. A. Sanchis-Lozano

We discuss the power scaling rules along the lines of a complete Heavy Quark Effective Field Theory (HQEFT) for the description of heavy quarkonium production through a color-octet mechanism. To this end, we firstly derive a tree-level heavy quark effective Lagrangian keeping both particle-antiparticle mixed sectors allowing for heavy quark-antiquark pair an

S. P. Baranov, N. P. Zotov

In the framework of the semihard ($k_T$ factorization) QCD approach, we consider the photoproduction of D* mesons associated with two hadron jets and the D* production in DIS at THERA conditions with the emphasis on the BFKL and CCFM dynamics of gluon distributions. In the photoproduction of D* mesons the attention is focused on the variable $x_γ$, which is

M. Gluck, E. Reya, C. Sieg

The implications of the positivity constraint, $|g_1^{γ(P^2)}(x,Q^2)| \leq F_1^{γ(P^2)}(x,Q^2)$, on the presently unknown spin--dependent structure function $g_1^{γ(P^2)}(x,Q^2)$ of real and virtual photons are studied at scales $Q^2\gg P^2$ where longitudinally polarized photons dominate physically relevant cross sections. In particular it is shown how to i

G. J. Gounaris, P. I. Porfyriadis, F. M. Renard

The process gamma gamma to ZH first arises at the 1-loop level, and as such it provides remarkable tests of the structure of the electroweak Higgs sector. These tests are complementary to those in the gauge sector involving gamma gamma to gamma gamma, gamma Z, ZZ. We show that in the Standard Model (SM) where H=H_{SM}, as well as in the supersymmetric case w

Chuan-Hung Chen, Chao-Qiang Geng

We study the exclusive decays of $B\to K^{(*)}l^+l^-$ within the framework of the PQCD. We obtain the form factors for the $B\to K^{(*)}$ transitions in all allowed values of $q^2$, which agree with the lattice results. We find that our distributions of the decay rates and leptonic asymmetries are consistent with that given in the other QCD models in the lit

Pankaj Jain, John P. Ralston

We review the current status of high energy exclusive processes and color transparency.

Roger D. Kylin

We extend a systematic renormalization procedure for quantum field theory to include particle masses and present several applications. We use a Hamiltonian formulation and light-front quantization because this may produce a convergent Fock-space expansion. The QCD Hamiltonian is systematically renormalized to second order in the strong coupling and the Fock-

K. Jimmy Juge, Julius Kuti, Colin Morningstar

Surface critical phenomena and the related onset of Goldstone modes represent fundamental properties of the confining flux in Quantum Chromodynamics. New ideas on surface roughening and their implications for lattice studies of quark confinement and string formation are presented. Problems with a simple string description of the large Wilson surface are disc

Colin Gay

The neutral $B$ mesons, $B^0$ and $B_s$, can oscillate between their particle and antiparticle states owing to flavor-changing weak interactions. In recent years, techniques to detect these oscillations as a function of the meson's decay time have been developed. In this article the physics of flavor oscillations is reviewed and theoretical predictions a

G. de Berredo-Peixoto, A. B. Penna-Firme, I. L. Shapiro

We calculate the one-loop divergences for quantum gravity with cosmological constant, using new parametrization of quantum metric. The conformal factor of the metric is treated as an independent variable. As a result the theory possesses an additional degeneracy and one needs an extra conformal gauge fixing. We verify the on shell independence of the diverge

Osvaldo M. Moreschi, Alejandro Perez

We study the possible asymptotically flat perturbations of Robinson-Trautman spacetimes. We differentiate between algebraically special perturbations and general perturbations. The equations that determine physically realistic spacetimes with angular momentum are presented.

G. E. Volovik

Traditionally it is assumed that the Casimir vacuum pressure does not depend on the ultraviolet cut-off. There are, however, some arguments that the effect actually depends on the regularization procedure and thus on the trans-Planckian physics. We provide the condensed matter example where the Casimir forces do explicitly depend on the microscopic (correspo

Luis P Chimento, Alejandro S Jakubi, Diego Pavon

We explore what restrictions may impose the second law of thermodynamics on varying speed of light theories. We find that the attractor scenario solving the flatness problem is consistent with the generalized second law at late time.

Valeria Del Prete, Alessandro Treves

In a recent study the initial rise of the mutual information between the firing rates of N neurons and a set of p discrete stimuli has been analytically evaluated, under the assumption that neurons fire independently of one another to each stimulus and that each conditional distribution of firing rates is gaussian. Yet real stimuli or behavioural correlates

Laurent Stainier, Alberto M. Cuitino, Michael Ortiz

The present paper is concerned with the development of a micromechanical model of the hardening, rate-sensitivity and thermal softening of bcc crystals. In formulating the model we specifically consider the following unit processes: double-kink formation and thermally activated motion of kinks; the close-range interactions between primary and forest dislocat

R. Fletcher, V. M. Pudalov, A. D. B. Radcliffe, C. Possanzini

This paper reports thermopower and conductivity measurements through the metal-insulator transition for 2-dimensional electron gases in high mobility Si-MOSFETs. At low temperatures both thermopower and conductivity show critical behaviour as a function of electron density. When approaching the critical density from the metallic side the diffusion thermopowe

M. Eremin, A. Rigamonti

The letter deals with the spin-freezing process observed by means of NMR-NQR relaxation or by muon spin rotation in underdoped cuprate superconductors. This phenomenon, sometimes referred as coexistence of antiferromagnetic and superconducting order parameters, is generally thought to result from randomly distributed magnetic moments related to charge inhomo

P. R. Huffman, C. R. Brome, J. S. Butterworth, S. N. Dzhosyuk

Magnetically stabilized luminescence is observed in hexagonal boron nitride. The luminescence is induced by absorption of cold neutrons and is in the visible region. In the absence of a magnetic field, the photon emission level is observed to decay over several hundred seconds. A fraction of this luminescence can be suppressed if the temperature is T <~ 0.6

A. E. Miroshnichenko, S. Flach, M. V. Fistul, Y. Zolotaryuk

We present a theoretical study of the resonant interaction between dynamical localized states (discrete breathers) and linear electromagnetic excitations (EEs) in Josephson junction ladders. By making use of direct numerical simulations we find that such an interaction manifests itself by resonant steps and various sharp switchings (voltage jumps) in the cur

J. R. Morris, K. M. Ho

We have performed molecular dynamic simulations of a Martensitic bcc->hcp transformation in a homogeneous system. The system evolves into three Martensitic variants, sharing a common nearest neighbor vector along a bcc <111> direction, plus an fcc region. Nucleation occurs locally, followed by subsequent growth. We monitor the time-dependent scattering S(q,t

R. E. S. Otadoy, A. Lodder

Andreev bound states in clean, ballistic SNS and SNSNS junctions are calculated exactly and by using the Andreev approximation (AA). The AA appears to break down for junctions with transverse dimensions chosen such that the motion in the longitudinal direction is very slow. The doubly degenerate states typical for the traveling waves found in the AA are repl

D. Pini, G. Stell, N. B. Wilding

We study a model for an argon-like fluid parameterised in terms of a hard-core repulsion and a two-Yukawa potential. The liquid-gas phase behaviour of the model is obtained from the thermodynamically self-consistent Ornstein-Zernike approximation (SCOZA) of Hoye and Stell, the solution of which lends itself particularly well to a pair potential of this form.

D. Herschkowitz, M. Opper

We study learning of probability distributions characterized by an unknown symmetry direction. Based on an entropic performance measure and the variational method of statistical mechanics we develop exact upper and lower bounds on the scaled critical number of examples below which learning of the direction is impossible. The asymptotic tightness of the bound

Angsula Ghosh, Sadhan K. Adhikari

We investigate the solution of the gap equation for mixed order parameter symmetry states as a function of filling using a two-dimensional tight-binding model incorporating second-neighbor hopping for tetragonal and orthorhombic lattice. The principal (major) component of the order parameter is taken to be of the $d_{x^2-y^2}$ type. As suggested in several i

Rafal Weron

The price of electricity is far more volatile than that of other commodities normally noted for extreme volatility. Demand and supply are balanced on a knife-edge because electric power cannot be economically stored, end user demand is largely weather dependent, and the reliability of the grid is paramount. The possibility of extreme price movements increase

Alessandro Torcini, Roberto Livi, Antonio Politi

In this paper we show that a dynamical description of the protein folding process provides an effective representation of equilibrium properties and it allows for a direct investigation of the mechanisms ruling the approach towards the native configuration. The results reported in this paper have been obtained for a two-dimensional toy-model of amino acid se

Ignacio Pagonabarraga, Alexander J. Wagner, M. E. Cates

By performing lattice Boltzmann simulations of a binary mixture, we scrutinize the dynamical scaling hypothesis for the spinodal decomposition of binary mixtures for the crossover region, i.e. the region of parameters in the growth curve where neither inertia nor viscous forces dominate the coarsening process. Our results give no evidence for a breakdown of

KA Benedict, RK Hills

Motivated by recent phonon spectroscopy experiments in the fractional quantum Hall regime we consider processes in which thermally excited magnetoroton excitations are scattered by low energy phonons. We show that such scattering processes can never give rise to dissociation of magnetorotons into unbound charged quasiparticles as had been proposed previously

Jyotipratim Ray Chaudhuri, Suman Kumar Banik, Bidhan Chandra Bag, Deb Shankar Ray

We consider a system-reservoir model where the reservoir is modulated by an external noise. Both the internal noise of the reservoir and the external noise are stationary, Gaussian and are characterized by arbitrary decaying correlation functions. Based on a relation between the dissipation of the system and the response function of the reservoir driven by e

Y. Asano

We discuss the Josephson current in superconductor / dirty normal conductor / superconductor junctions, where the superconductors have $d_{x^2-y^2}$ pairing symmetry. The low-temperature behavior of the Josephson current depends on the orientation angle between the crystalline axis and the normal of the junction interface. We show that the ensemble-averaged

Yoshihiro Takushima, Akihisa Koga, Norio Kawakami

We investigate quantum phase transitions among the spin-gap phases and the magnetically ordered phases in a two-dimensional frustrated antiferromagnetic spin system, which interpolates several important models such as the orthogonal-dimer model as well as the model on the 1/5-depleted square lattice. By computing the ground state energy, the staggered suscep

Alexander J. Wagner, Ignacio Pagonabarraga

Lees Edwards boundary conditions (LEbc) for Molecular Dynamics simulations are an extension of the well known periodic boundary conditions and allow the simulation of bulk systems in a simple shear flow. We show how the idea of LEbc can be implemented in lattice Boltzmann simulations and how LEbc can be used to overcome the problem of a maxinum shear rate th

A. S. Evans, D. T. Frayer, J. A. Surace, D. B. Sanders

Millimeter-wave (CO) observations of optically-selected QSOs are potentially a powerful tool for studying the properties of both the QSOs and their host galaxies. We summarize here a recent molecular gas survey of z<0.17 optical QSOs with infrared (IR) excess, L_IR (8-1000 um) / L_bbb (0.1-1.0 um) > 0.36. Eight of these QSOs have been detected to date in CO(

F. Halzen

Of all high-energy particles, only neutrinos can directly convey astronomical information from the edge of the universe---and from deep inside the most cataclysmic high-energy processes. Copiously produced in high-energy collisions, travelling at the velocity of light, and not deflected by magnetic fields, neutrinos meet the basic requirements for astronomy.

Pedro F. Gonzalez-Diaz

By using a tracking quintessence model we obtain that the position of the first Doppler peak in the spectrum of CMB anisotropies only depends on the topology of the universe, $Ω_k$, for any value of the ratio $Ω_Λ/Ω_M$, so that such a dependence is perfectly valid in the range suggested by supernova observations.

David R. Andersen, Matthew A. Bershady, Linda S. Sparke, John S. Gallagher

We have measured the intrinsic disk ellipticity for 7 nearby, nearly face-on spiral galaxies by combining Densepak integral-field spectroscopy with I-band imaging from the WIYN telescope. Initially assuming an axisymmetric model, we determine kinematic inclinations and position angles from H-alpha velocity fields, and photometric axis ratios and position ang

Claire J. Chandler, John S. Richer

We present images of the HH 211 molecular jet in the SiO v=0, J=1-0 line at 43 GHz made with the Very Large Array at approximately 0.5 arcsec resolution. The SiO emission appears to trace primarily internal bowshocks in the outflow, suggesting that the dust and molecular gas are accelerated via prompt entrainment at internal working surfaces in the jet. Ther

D. Molteni, G. Gerardi, M. A. Valenza

Using simple arguments we show that the canonical thin keplerian accretion disks cannot smoothly match any plain advection dominated flow (ADAF) model. By &#39;plain&#39; ADAF model we mean the ones with zero cooling. The existence of sonic points in exact solutions is critical and imposes constraints that cannot be surpassed adopting &#39;reasonable&#39; ph

G. Kovacs, A. R. Walker

Our former study on the empirical relations between the Fourier parameters of the light curves of the fundamental mode RR Lyrae stars and their basic stellar parameters has been extended to considerably larger data sets. The most significant contribution to the absolute magnitude M_v comes from the period P and from the first Fourier amplitude A_1, but there

T. R. Geballe, D. Saumon, S. K. Leggett, G. R. Knapp

We have obtained a good quality R$\sim$400 0.8-2.5 $\mu$m spectrum and accurate photometry of Gl 570D, one of the coolest and least luminous brown dwarfs currently known. The spectrum shows that Gl 570D has deeper absorptions in the strong water and methane bands at 1.12-1.17 $\mu$m, 1.33-1.45 $\mu$m, 1.62-1.88 $\mu$m, and 2.20-2.45 $\mu$m and is both bluer

Eli Waxman

A review is presented of the fireball model of gamma-ray bursts (GRBs), and of the production in GRB fireballs of high energy protons and neutrinos. Constraints imposed on the model by recent afterglow observations, which support the association of GRB and ultra-high energy cosmic-ray (UHECR) sources, are discussed. Predictions of the GRB model for UHECR pro

C. Spangler, A. I. Sargent, M. D. Silverstone, E. E. Becklin

Using ISO-ISOPHOT we carried out a survey of almost 150 stars to search for evidence of emission from dust orbiting young main sequence stars, both in clusters and isolated systems. Over half of the detections are new examples of dusty stellar systems, and demonstrate that such dust can be detected around numerous stars older than a few x 10^6 years. Fluxes

J. D. Monnier, L. J. Greenhill, P. G. Tuthill, W. C. Danchi

This paper discusses our ongoing efforts to characterize dust-enshrouded Wolf-Rayet (WR) stars in the radio and infrared. We have used the Very Large Array to measure the broadband radio spectrum of WR stars in suspected binary systems and discovered non-thermal emission, which is usually attributed to colliding winds. In addition, infrared imaging using ape

X. -Y. Xia, Th. Boller, Z. -G. Deng, G. Borner

We report on the results of the cross-correlation of a sample of 903 Ultraluminous IRAS galaxies (ULIRGs) with the ROSAT-All Sky Survey Bright Source Catalogue and the ROSAT archived pointing observations. The sample of ULIRGs has been compiled from the PSCz redshift survey. In total, 35 ULIRGs are securely detected by the ROSAT All-Sky Survey and pointing o

Sergey P. Trudolyubov

Using the data of 5 years of RXTE observations we investigate the X-ray spectral and timing properties of GRS 1915+105 during the hard steady states. According to the results of our simultaneous X-ray spectral and timing analysis the behavior the source during the hard steady states can be reduced to a couple of major distinct types. i) Type I states: The do

Crystal L. Martin, Robert C. Kennicutt,

We report the first results of a detailed study of the star formation law in a sample of 32 nearby spiral galaxies with well-measured rotation curves, HI and H$_2$ (as traced by CO) surface density profiles, and new \Ha CCD photometry. Our results strongly support the view that the formation of gravitationally bound interstellar clouds regulates the onset of

R. T. Zavala, G. B. Taylor

Multifrequency polarimetry with the VLBA confirms the previously reported time-varying Faraday rotation measure (RM) in the quasar 3C-279. Variability in the RM and electric vector position angle (EVPA) of the jet component (C4) is seen making it an unreliable absolute EVPA calibrator. 3C-273 is also shown to vary its RM structure on 1.5 year time-scales. Va

D. L. Kaplan, S. R. Kulkarni, M. H. van Kerkwijk, R. E. Rothschild

Soft Gamma-ray Repeaters (SGRs) are among the most enigmatic sources known today. Exhibiting huge X- and Gamma-ray bursts and flares, as well as soft quiescent X-ray emission, their energy source remains a mystery. Just as mysterious are the Anomalous X-ray pulsars (AXPs), which share many of the same characteristics. Thanks to recent Chandra observations, S

Marshall Joy, John E. Carlstrom

The cosmic microwave background radiation (CMBR) is providing important clues into the evolution of the early universe. In this Science Perspective, Joy and Carlstrom discuss one feature of the CMBR, the Sunyaev-Zel&#39;dovich effect, which can be used to determine the abundance and evolution of clusters of galaxies, thereby constraining key cosmological par

Sheldon Katz, Chiu-Chu Melissa Liu

In this paper, we present foundational material towards the development of a rigorous enumerative theory of stable maps with Lagrangian boundary conditions, ie stable maps from bordered Riemann surfaces to a symplectic manifold, such that the boundary maps to a Lagrangian submanifold. Our main application is to a situation where our proposed theory leads to

A. R. Mondragon, R. E. Allen

It is commonly believed that the vacuum energy problem points to the need for (1) a radically new formulation of gravitational physics and (2) a new principle which forces the vacuum stress-energy tensor (as measured by gravity) to be nearly zero. Here we point out that a new fundamental theory contains both features: (1) In this theory the vierbein is inter

Duane A. Dicus, Hong-Jian He, John N. Ng

Evidence for neutrino oscillations is pointing to the existence of tiny but finite neutrino masses. Such masses may be naturally generated via radiative corrections in models such as the Zee model where a singlet Zee-scalar plays a key role. We minimally extend the Zee model by including a right-handed singlet neutrino ν_R. The radiative Zee-mechanism can be

G. Arreaga, R. Capovilla, C. Chryssomalakos, J. Guven

We determine the equilibria of a rigid loop in the plane, subject to the constraints of fixed length and fixed enclosed area. Rigidity is characterized by an energy functional quadratic in the curvature of the loop. We find that the area constraint gives rise to equilibria with remarkable geometrical properties: not only can the Euler-Lagrange equation be in

Xiangdong Ji, Chulwoo Jung

We calculate the first moment of the photon structure function, $<x>^γ=\int^1_0 dx F^γ_2(x,Q^2)$, on the quenched lattices with $β=6.0$ using the formalism developed by the authors recently. In this exploratory study, we take into account only the connected contractions. The result is compared with the experimental data as well as model predictions.

Lawrence Hall, Yasunori Nomura

A complete 5-dimensional SU(5) unified theory is constructed which, on compactification on the orbifold with two different Z_2&#39;s (Z_2 and Z_2&#39;), yields the minimal supersymmetric standard model. The orbifold accomplishes SU(5) gauge symmetry breaking, doublet-triplet splitting, and a vanishing of proton decay from operators of dimension 5. Until 4d s

Bernard de Wit

I review electric-magnetic duality from the perspective of extended supergravity theories in four spacetime dimensions

S. Bose, I. Fuentes-Guridi, P. L. Knight, V. Vedral

We show that entanglement can always arise in the interaction of an arbitrarily large system in any mixed state with a single qubit in a pure state. This small initial purity is enough to enforce entanglement even when the total entropy is close to maximum. We demonstrate this feature using the Jaynes-Cummings interaction of a two level atom in a pure state

Ian Ellwood, Washington Taylor

Witten&#39;s cubic open string field theory is expanded around the perturbatively stable vacuum, including all scalar fields at levels 0, 2, 4 and 6. The (approximate) BRST cohomology of the theory is computed, giving strong evidence for the absence of physical open string states in this vacuum.

L. Grandchamp, R. Rapp

The production of $J/Ψ$ mesons in central collisions of heavy nuclei is investigated as a function of collision energy. Two contributions are considered simultaneously: early (hard) production coupled with subsequent suppression in a Quark-Gluon Plasma, as well as thermal recombination of primordially produced $c$ and $\bar c$ quarks at the hadronization tra

Denis Perrot

In this paper we construct a bivariant Chern character defined on ``families of spectral triples&#39;&#39;. Such families should be viewed as a version of unbounded Kasparov bimodules adapted to the category of bornological algebras. The Chern character then takes its values in the bivariant entire cyclic cohomology of Meyer. The basic idea is to work within

Debrupa Chakraverty, Anindya Datta, Biswarup Mukhopadhyaya

We investigate b-quark production in both charged and neutral current channels through neutrino-nucleon scattering at a neutrino factory, mediated by the lepton flavour violating interactions present in a supersymmetric theory with broken R-parity. Using values of the effctive interaction strengths well below the current and projected experimental bounds, we

Predrag Lazic, D. K. Sunko

A bond-disordered two-dimensional Ising model is used to simulate Kauzmann&#39;s mechanism of vitrification in liquids, by a Glauber Monte Carlo simulation. The rearrangement of configurations is achieved by allowing impurity bonds to hop to nearest neighbors at the same rate as the spins flip. For slow cooling, the theoretical minimum energy configuration i

Michael Gronau, Yuval Grossman, Jonathan L. Rosner

We propose a set of measurements at a charm factory to determine the $D^0-\bar D^0$ mixing parameters $ΔM$ and $ΔΓ$ and the strong phase difference $δ$ between doubly-Cabibbo-suppressed (DCS) and Cabibbo-favored (CF) neutral $D$ decays into $K^-π^+$. The method can also be used to measure strong phase differences between other corresponding DCS and CF amplit

G. Sambandamurthy, K. Das Gupta, N. Chandrasekhar

Current-voltage (I-V) characteristics of quench condensed, superconducting, ultrathin $Bi$ films in a magnetic field are reported. These I-V&#39;s show hysteresis for all films, grown both with and without thin $Ge$ underlayers. Films on Ge underlayers, close to superconductor-insulator transition (SIT), show a peak in the critical current, indicating a stru

Ming-Hsien Tu

We consider the Gelfand-Dickey (GD) structure defined by the Moyal $\star$-product with parameter $\ka$, which not only defines the bi-Hamiltonian structure for the generalized Moyal KdV hierarchy but also provides a $W_n^{(\ka)}$ algebra containing the Virasoro algebra as a subalgebra with central charge $\ka^2(n^3-n)/3$. The free-field realization of the $

Alex Kaivarainen

The coherent physical theory of Psi phenomena is absent till now due to its high complexity and multilateral character. The original mechanism of Bivacuum mediated Psi phenomena, proposed here, is based on few stages of my long term efforts. They include creation of new theories: 1) Unified theory of Bivacuum, matter and fields duality, mass and charge origi

R. Manvelyan, R. Mkrtchyan, H. J. W. Mueller-Kirsten

The behavior of the divergent part of the bulk AdS/CFT effective action is considered with respect to the special finite diffeomorphism transformations acting on the boundary as a Weyl transformation of the boundary metric. The resulting 1-cocycle of the Weyl group is in full agreement with the 1-cocycle of the Weyl group obtained from the cohomological cons

G. Wilk, Z. Wlodarczyk

We demonstrate that non-exponential decays of unstable systems can be understood as yet another example of nonextensivity encountered in many physical systems and as such can be characterized by the nonextensivity parameter q.

Mariusz Michalec, Wojciech Florkowski, Wojciech Broniowski

By means of a simple rescaling, modifications of hadron masses and widths are incorporated into the thermal analysis of particle ratios in ultra-relativistic heavy-ion collisions. We find that moderate, up to 20%, changes of hadron masses do not spoil the quality of the fits, which remain as good as those obtained without modifications. The fits with the mod

Yoav Tsori, David Andelman

We investigate the effect of chemically patterned surfaces on the morphology of diblock copolymers below the order-disorder transition. Profiles for lamellar phases in contact with one surface, or confined between two surfaces are obtained in the weak segregation limit using a Ginzburg-Landau expansion of the free energy, and treating it with mean-field theo

A. P. Bakulev, S. V. Mikhailov, N. G. Stefanis

We use QCD sum rules with nonlocal condensates to re-calculate more accurately the moments and their confidence intervals of the twist-2 pion distribution amplitude including radiative corrections. We are thus able to construct an admissible set of pion distribution amplitudes which define a reliability region in the $a_{2}$, $a_{4}$ plane of the Gegenbauer

Watson Kuo, C. D. Chen

We have studied experimentally the magnetic field-induced superconductor-insulator quantum phase transition in one-dimensional arrays of small Josephson junctions. The zero bias resistance was found to display a drastic change upon application of a small magnetic field; this result was analyzed in context of the superfluid-insulator transition in one dimensi

Carlo Michel Carloni Calame

An improved QED Parton Shower algorithm to calculate photonic radiative corrections to QED processes at flavour factories is described. We consider the possibility of performing photon generation in order to take into account also the effects due to interference between initial and final state radiation. Comparisons with exact order $α$ results are shown and

Miloslav Znojil

The Feshbach-type reduction of the Hilbert space to the physically most relevant &#34;model&#34; subspace is suggested as a means of a formal unification of the standard quantum mechanics with its recently proposed PT symmetric modification. The resulting &#34;effective&#34; Hamiltonians H(eff) are always Hermitian, and the two alternative forms of their ene

Heng Fan, Keiji Matsumoto, Miki Wadati

The optimal N to M ($M>N$) quantum cloning machines for the d-level system are presented. The unitary cloning transformations achieve the bound of the fidelity.

Chih-Lung Chou, Chung-Hsien Chou

In the gauge-mediated supersymmetry breaking models with scalar tau as the next-to-lightest supersymmetric particle, a scalar lepton may decay dominantly into its superpartner, tau lepton, and the lightest scalar tau particle. We give detailed formulas for the three-body decay amplitudes and the polarization asymmetry of the outgoing tau lepton . We find tha

Jun&#39;ichi Yokoyama, Yoshiaki Himemoto

Reheating or entropy production on the three-brane from a decaying bulk scalar field is studied in the brane-world picture of the Universe. It is shown that a significant amount of dark radiation is produced in this process unless only the specific modes are excited, so that subsequent entropy production within the brane is required in general before primord

G. E. Brown, Mannque Rho

This article reviews our view on how chiral symmetry, its pattern of breaking and restoration under extreme conditions manifest themselves in the nucleon, nuclei, nuclear matter and dense hadronic matter. Topics treated are nucleon structure in terms of chiral symmetry, &#34;first-principle&#34; (QCD) calculations of the properties of finite nuclei effectuat

Fu-Guang Cao, A. I. Signal

We present a study of the flavour asymmetry of polarized anti-quarks in the nucleon using the meson cloud model. We include contributions both from the vector mesons and the interference terms of pseudoscalar and vector mesons. Employing the bag model, we first give the polarized valence quark distribution of the $\rho$ meson and the interference distributio

Tomoyuki Takenawa

A method to calculate the algebraic entropy of a mapping which can be lifted to an isomorphism of a suitable rational surfaces (the space of initial values) are presented. It is shown that the degree of the $n$th iterate of such a mapping is given by its action on the Picard group of the space of initial values. It is also shown that the degree of the $n$th

Guang-jiong Ni

The recent experiment on superconducting quantum interference device provides new opportunity to clarify the fundamental interpretation of quantum mechanics. After analyzing this and relevant experiments, we claim the point of view that the quantum state in abstract sense contains no information and the wave function is the probability amplitude of fictitiou

Emilio Santos

The conjecture is made that quantum mechanics is compatible with local hidden variables (or local realism). The conjecture seems to be ruled out by the theoretical argument of Bell, but it is supported by the empirical fact that nobody has been able to perform a loophole-free test of local realism in spite of renewed effort during almost 40 years.

Xiaoguang Wang

We introduce the nonlinear spin coherent state via its ladder operator formalism and propose a type of nonlinear spin coherent state by the nonlinear time evolution of spin coherent states. By a new version of spectroscopic squeezing criteria we study the spin squeezing in both the spin coherent state and nonlinear spin coherent state. The results show that

M. D. Bowdrey, J. A. Jones

We describe a simple scheme for calculating the fidelity of a composite pulse when considered as a universal rotor.

I. Carusotto, M. Artoni, G. C. La Rocca, F. Bassani

We theoretically study the effect of ultraslow group velocities on the emission of Vavilov-Cherenkov radiation in a coherently driven medium. We show that in this case the aperture of the group cone on which the intensity of the radiation peaks is much smaller than that of the usual wave cone associated with the Cherenkov coherence condition. We show that su

Hitoshi Inamori, Luke Rallan, Vlatko Vedral

We investigate a new strategy for incoherent eavesdropping in Ekert&#39;s entanglement based quantum key distribution protocol. We show that under certain assumptions of symmetry the effectiveness of this strategy reduces to that of the original single qubit protocol of Bennett and Brassard.

Christoph Simon

This thesis consists of four parts. In the first part it is shown that optimal universal cloning of photons can be realized with the help of stimulated emission. Possible schemes based on three-level systems and on parametric down-conversion are analyzed in detail. The second part shows that the dynamical rules of quantum physics can be derived from its stat

Antia Lamas-Linares, Christian Mikkelsen, John C. Howell, D. Bouwmeester

Inspired by laser operation, we address the question of whether stimulated emission into polarization entangled modes can be achieved. We describe a state produced by stimulated emission of the singlet Bell state and propose a setup for creating it. As a first important step towards an entangled-photon laser we demonstrate experimentally interference-enhance

M. E. Madjet, Himadri S. Chakraborty, Jan-M. Rost

We find that for simple metal clusters a single-electron description of the ground state employing self-interaction correction (SIC) in the framework of local-density approximation strongly contaminates the high energy photoionization cross sections with spurious oscillations for a subshell containing node(s). This effect is shown connected to the unphysical

Hanns L. Harney

The Gaussian theory of errors has been generalized to situations, where the Gaussian distribution and, hence, the Gaussian rules of error propagation are inadequate. The generalizations are based on Bayes&#39; theorem and a suitable measure. The following text sketches some chapters of a monograph that is presently prepared. We concentrate on the material th

L. A. Gevorgian, R. V. Tumanian

Crystallization and radiation of accelerator beams is considered. For the first time it is shown that crystallization conditions for charged particle beams differs from those of plasma. Crystallization conditions of charged relativistic bunches are found and shown that they may be satisfies in existing linacs. The coherence radiation of crystalline beams in

V. V. Lyahov, V. M. Nechshadim

Some aspects of the development of physics and the mathematics set one think about relation between complex numbers and reality around us. If number to spot as the relation of two quantities, from the fact of existence of complex numbers and accepted definition of number it is necessary necessity complex value to assign to all physical quantities. The basic

W. M. Itano

Frequency shifts of the ^199Hg^+ 5d^10 6s ^2S_1/2 (F=0, M_F=0) to 5d^9 6s^2 ^2D_5/2 (F=2, M_F=0) electric-quadrupole transition at 282 nm due to external fields are calculated, based on a combination of measured atomic parameters and ab initio calculations. This transition is under investigation as an optical frequency standard. The perturbations calculated

V. Maddalena, R. Shyam

We analyze the recently obtained new data on the partial cross sections and parallel momentum distributions for transitions to ground as well as excited states of the 16C core, in the one-neutron removal reaction 197Au(17C,16C gamma)X at the beam energy of 61 MeV/nucleon. The Coulomb and nuclear breakup components of the one-neutron removal cross sections ha

M. Lakshmanan, T. Kanna, R. Radhakrishnan

Wecritically review the recent progress in understanding soliton propagation in birefringent optical fibers.By constructing the most general bright two-soliton solution of the integrable coupled nonlinear Schroedinger equation (Manakov model) we point out that solitons in birefringent fibers can in general change their shape after interaction due to a change

G. G. Amosov, A. S. Holevo

A multiplicativity conjecture for quantum communication channels is formulated, validity of which for the values of parameter $p$ close to 1 is related to the solution of the fundamental problem of additivity of the channel capacity in quantum information theory. The proof of the conjecture is given for the case of natural numbers $p$.

K. A. Volosov

We propose a new method based on the invariant properties of the ansatz of the Hirota method which have been discovered recently. This method allows one to construct new solutions for a certain class the dissipative equations classified by degrees of homogeneity. This algorithm is similar to the method of ``dressing&#39;&#39; the solutions of integrable equa