June 1999 arXiv papers — page 10

K. Shiokawa

Multistep Bose-Einstein condensation of an ideal Bose gas in anisotropic harmonic atom traps is studied. In the presence of strong anisotropy realized by the different trap frequency in each direction, finite size effect dictates a series of dimensional crossovers into lower-dimensional excitations. Two-step condensation and the dynamical reduction of the ef

Steven A. Balbus

The stratification of entropy and the stratification of angular momentum are closely analogous. Of particular interest is the behavior of disks in which angular momentum transport is controlled by convection, and heat transport by dynamical turbulence. In both instances we argue that the transport must proceed ``backwards'' relative to the sense one

A. Mondragon, E. Rodriguez-Jauregui

The phase equivalence of the theoretical mixing matrix ${\bf V}^{th}$ derived from the breaking of the flavour permutational symmetry and the standard parametrization ${\bf V}^{PDG}$ advocated by the Particle Data Group is explicitly exhibited. From here, we derive exact explicit expressions for the three mixing angles $θ_{12}$, $θ_{13}$, $θ_{23}$, and the C

Sergey Prokushkin, Mikhail Vasiliev

We study conserved currents of any integer or half integer spin built from massless scalar and spinor fields in $AdS_3$. 2-forms dual to the conserved currents in $AdS_3$ are shown to be exact in the class of infinite expansions in higher derivatives of the matter fields with the coefficients containing inverse powers of the cosmological constant. This prope

O. M. Del Cima, J. M. Grimstrup, M. Schweda

A new topological model is proposed in three dimensions as an extension of the BF-model. It is a three-dimensional counterpart of the two-dimensional model introduced by Chamseddine and Wyler ten years ago. The BFK-model, as we shall call it, shows to be quantum scale invariant at all orders in perturbation theory. The proof of its full finiteness is given i

Andrew W. Blain, Allon Jameson, Ian Smail, Malcolm Longair

A large fraction of the luminous distant submm-wave galaxies recently detected using SCUBA on the JCMT appear to be associated with interacting optical counterparts. We investigate these systems using a simple hierarchical clustering model of galaxy evolution, in which the large luminosity of the SCUBA galaxies is assumed to be generated at the epoch of gala

Emil M. Prodanov, Siddhartha Sen

We show that on three-dimensional Riemannian manifolds without boundaries and with trivial first real de Rham cohomology group (and in no other dimensions) scalar field theory and Maxwell theory are equivalent: the ratio of the partition functions is given by the Ray-Singer torsion of the manifold. On the level of interaction with external currents, the equi

Dmitri Sorokin

We review the geometrical approach to the description of the dynamics of super-p-branes, Dirichlet branes and the M5-brane, which is based on a generalization of the elements of surface theory to the description of the embedding of supersurfaces into target superspaces. Being manifestly supersymmetric in both, the superworldvolume of the brane and the target

R. Donangelo, K. Sneppen

We study the dynamics of exchange value in a system composed of many interacting agents. The simple model we propose exhibits cooperative emergence and collapse of global value for individual goods. We demonstrate that the demand that drives the value exhibits non Gaussian "fat tails" and typical fluctuations which grow with time interval with a Hurs

Diego Harari, Silvia Mollerach, Esteban Roulet

We study the effects of the galactic magnetic field on the ultra high energy cosmic ray propagation. We show that the deflections of the cosmic ray trajectories can have many important implications such as (de)magnification of the cosmic ray fluxes by lensing effects (which can modify the spectrum of individual sources), the formation of multiple images of a

R. V. Gavai, Sourendu Gupta

We present the first measurement of a new correlation function of Fermion bilinears in finite temperature QCD with and without dynamical quarks in a quantum number channel in which non-trivial correlations are known to be present for purely gluonic operators. We find that the Fermion correlator vanishes for $T \ge 3T_c/2$, in agreement with the expectation f

I. G. Mitrofanov, M. L. Litvak, M. S. Briggs, W. S. Paciesas

Six intensity groups with ~150 BATSE gamma-ray bursts each are compared using average emissivity curves. Time-stretch factors for each of the dimmer groups are estimated with respect to the brightest group, which serves as the reference, taking into account the systematics of counts-produced noise effects and choice statistics. A stretching/intensity anti-co

I. L. Buchbinder, M. Cvetic, A. Yu. Petrov

We study the decoupling effects in N=1 (global) supersymmetric theories with chiral superfields at the one-loop level. The examples of gauge neutral chiral superfields with the minimal (renormalizable) as well as non-minimal (non- renormalizable) couplings are considered, and decoupling in gauge theories with U(1) gauge superfields that couple to heavy chira

Tomasz Masłowski, Stanisław D. Głazek

This manuscript (hep-th/9906140v1) is incomplete. Please read instead S. D. Głazek, T. Masłowski, Renormalized Poincaré algebra for effective particles in quantum field theory, Phys.Rev. D65 (2002) 065011, (hep-th/0110185).

Vincenzo Piazza, Vittorio Pellegrini, Fabio Beltram, Werner Wegscheider

The single-particle energy spectrum of a two-dimensional electron gas in a perpendicular magnetic field consists of equally-spaced spin-split Landau levels, whose degeneracy is proportional to the magnetic field strength. At integer and particular fractional ratios between the number of electrons and the degeneracy of a Landau level (filling factors n) quant

Kaiki Taro Inoue, Kenji Tomita, Naoshi Sugiyama

The effect of a non-trivial topology on the temperature correlations on the cosmic microwave background (CMB) in a small compact hyperbolic universe with volume comparable to the cube of the curvature radius is investigated. Because the bulk of large-angular CMB fluctuations is produced at the late epoch in low $Ω_0$ models, the effect of a long wavelength c

Igor Bray, Justin Beck, Chris Plottke

Electron-impact ionization of lithium is studied using the convergent close-coupling (CCC) method at 25.4 and 54.4 eV. Particular attention is paid to the spin-dependence of the ionization cross sections. Convergence is found to be more rapid for the spin asymmetries, which are in good agreement with experiment, than for the underlying cross sections. Compar

Luis Santos, Maciej Lewenstein

We analyse the effects of atom-atom collisions on collective laser cooling scheme. We derive a quantum Master equation which describes the laser cooling in presence of atom-atom collisions in the weak-condensation regime. Using such equation, we perform Monte Carlo simulations of the population dynamics in one and three dimensions. We observe that the ground

Boris Grishanin, Victor Zadkov

A system of two closely spaced atoms interacting through a vacuum electromagnetic field is considered. It is demonstrated that radiative decay in such a system resulting from photon exchange gives rise to a definite amount of information related to interatomic communication. Joint distributions of detection probabilities of atomic quanta and the correspondin

J. Audretsch, M. B. Mensky, A. D. Panov

We consider a driven 2-level system with one level showing spontaneous decay to an otherwise uncoupled third level. Rabi transitions to the unstable level are strongly damped. This simple configuration can be used to demonstrate and to explore the quantum Zeno effect leading to a freezing of the system to the initial level. A comparison with repeated project

G. M. D'Ariano, M. Rubin, M. F. Sacchi, Y. Shih

We present a method of generation of the Greenberger-Horne-Zeilinger state involving type II and type I parametric downconversion, and triggering photodetectors. The state generated by the proposed experimental set-up can be reconstructed through multi-mode quantum homodyne tomography. The feasibility of the measurement is studied on the basis of Monte-Carlo

R. E. S. Polkinghorne, T. C. Ralph

We investigate the efficacy with which entanglement can be teleported using a continuous measurement scheme. We show that by using the correct gain for the classical channel the degree of violation of locality that can be demonstrated (using a CH type inequality) is {\it not} a function of the level of entanglement squeezing used in the teleportation. This i

M. A. Pravia, E. Fortunato, Y. Weinstein, M. D. Price

NMR is emerging as a valuable testbed for the investigation of foundational questions in quantum mechanics. The present paper outlines the preparation of a class of mixed states, called pseudo-pure states, that emulate pure quantum states in the highly mixed environment typically used to describe solution-state NMR samples. It also describes the NMR observat

Boris Grishanin, Victor Zadkov

A problem of inducing a required sign of chirality in a racemic mixture of enantiomers of a chiral molecule is analyzed. As an example, a racemic mixture (vapor) of left- and right-handed enantiomers of hydrogen peroxide (H2O2) molecule is considered. It is shown that biharmonic Raman excitation of the splitted due to the left-right conversion internal rotat

Qun Li, Yang Pang, Nu Xu

We study the mechanism of transverse energy (E_T) production in Au+Au collisions at RHIC. The time evolution starting from the initial energy loss to the final E_T production is closely examined in transport models. The relationship between the experimentally measured E_T distribution and the maximum energy density achieved is discussed.

Felix Boehm

We review the status and the results of reactor neutrino experiments. Long baseline oscillation experiments at Palo Verde and Chooz have provided limits for the oscillation parameters while the recently proposed Kamland experiment at a baseline of more than 100km is now in the planning stage. We also describe the status of neutrino magnetic moment experiment

Brian Harbourne, Sandeep Holay, Stephanie Fitchett

Let I be the ideal corresponding to a set of general points $p_1,...,p_n \in P^2$. There recently has been progress in showing that a naive lower bound for the Hilbert functions of symbolic powers $I^{(m)}$ is in fact attained when n>9. Here, for m sufficiently large, the minimal free graded resolution of $I^{(m)}$ is determined when n>9 is an even square, a

Peter Saveliev

We provide theorems containnig both Kakutani and Browder fixed points theorems as immediate corollaries, as well as Michael and Browder selection theorems. For this purpose we introduce convex structures more general than those of locally convex and non-locally convex topological vector spaces or generalized convexity structures due to Michael, Van de Vel an

J. E. Fornaess

In this paper we investigate complex dynamics in infinite dimensions.

Alexandr Borisov

The author was recently able to provide a cohomological interpretation of Tate's Riemann-Roch formula for number fields using some new harmonic analysis objects, ghost-spaces. When trying to investigate these objects in general, we realized the importance of functions and measures on locally compact abelian groups that are both positive and positive-defi

Vladimir Tchernov

Recently V. Arnold introduced Strangeness and $J^{\pm}$ invariants of generic immersions of an oriented circle to $\R^2$. Here these invariants are generalized to the case of generic immersions of an oriented circle to an arbitrary surface $F$. We explicitly describe all the invariants satisfying axioms, which naturally generalize the axioms used by V. Arnol

Vladimir Tchernov

We explicitly calculate the fundamental group of the space $\mathcal F$ of all immersed closed curves on a surface $F$. It is shown that $π_n(\mathcal F)=0$, n>1 for $F\neq S^2, RP^2$. It is also proved that $π_2(\mathcal F)=\Z$, and $π_n(\mathcal F)=π_n(S^2)\oplusπ_{n+1}(S^2)$, n>2, for $F$ equal to $S^2$ or $RP^2$.

L. Paris, D. Rolfsen

This paper is a study of the subgroups of the mapping class groups of Riemann surfaces, called "geometric" subgroups, corresponding to the inclusion of subsurfaces. Our analysis includes surfaces with boundary and with punctures. The centres of all the mapping class groups are calculated. We determine the kernel of inclusion-induced maps of the mappi

Vladimir Tchernov

A first order Vassiliev invariant of an oriented knot in an $S^1$-fibration and a Seifert fibration over a surface is constructed. It takes values in a quotient of the group ring of the first homology group of the total space of the fibration. It gives rise to an invariant of wave fronts on surfaces and orbifolds related to the Bennequin-type invariants of t

Eugene Lerman

We generalize the Weinstein-Moser theorem on the existence of nonlinear normal modes (i.e., periodic orbits) near an equilibrium in a Hamiltonian system to a theorem on the existence of relative periodic orbits near a relative equilibrium in a Hamiltonian system with continuous symmetries. More specifically we significantly improve a result proved earlier jo

Dmitry Arinkin, Alexander Polishchuk

We construct a version of Fourier transform for families of real tori. This transform defines a functor from certain category associated with a symplectic family of tori to the category of holomorphic vector bundles on the dual family (the dual family has a natural complex structure). In the 1-dimensional case the former category is closely related to the Fu

C. Munoz

In this talk I summarize several recent results concerning the four-dimensional effective supergravity obtained using a Calabi-Yau compactification of the $E_8\times E_8$ heterotic string from M-theory. A simple macroscopic study is provided expanding the theory in powers of two dimensionless variables. Higher order terms in the Kähler potential are identifi

C. -W. H. Lee, S. G. Rajeev

To formulate two-dimensional Yang-Mills theory with adjoint matter fields in the large-N limit as classical mechanics, we derive a Poisson algebra for the color-invariant observables involving adjoint matter fields. We showed rigorously in J. Math. Phys. 40, 1870 (1999) that different quantum orderings of the observables produce essentially the same Poisson

John Ellis, Zygmunt Lalak, Stefan Pokorski, Steven Thomas

We discuss supersymmetry breaking in the field-theoretical limit of the strongly-coupled heterotic string compactified on a Calabi-Yau manifold, from the different perspectives of four and five dimensions. The former applies to light degrees of freedom below the threshold for five-dimensional Kaluza-Klein excitations, whereas the five-dimensional perspective

Agustin Nieto, Michel H. G. Tytgat

We study the perturbation expansion of the free energy of N=4 supersymmetric SU(N) Yang-Mills at finite temperature in powers of 't Hooft's coupling g^2 N in the large N limit. Infrared divergences are controlled by constructing a hierarchy of two 3 dimensional effective field theories. This procedure is applied to the calculation of the free energy

M. Chaichian, W. F. Chen, C. Montonen

We review a detailed investigation of the perturbative part of the low-energy effective action of N=2 supersymmetric Yang-Mills theory in a conventional effective field theory approach. With the restriction that the effective action should contain at most two derivatives and not more than four-fermion couplings, the features of the low-energy effective actio

T. P. Branson, P. B. Gilkey, K. Kirsten, D. V. Vassilevich

We calculate the coefficient $a_5$ of the heat kernel asymptotics for an operator of Laplace type with mixed boundary conditions on a general compact manifold.

A. Hatzinikitas

We investigate the behaviour of a particle moving on the quotient manifold $M=C^2/Z_$ which is derived from the EH metric as the two centers approach each other. In the classical region of the configuration space we specify the physically acceptable solutions and observe a tendency of the radial wave function to concentrate around the conical singularity. Fo

H. J. Drescher, M. Hladik, S. Ostapchenko, K. Werner

We present a new parton model approach for nuclear collisions at RHIC energies (and beyond). It is a selfconsistent treatment, using the same formalism for calculating cross sections like the total and the inelastic one and, on the other hand, particle production. Actually, the latter one is based on an expression for the total cross section, expanded in ter

Francesca Rosati

Recent data point in the direction of a cosmological constant dominated universe. We investigate the role of supersymmetric QCD with N_f < N_c as a possible candidate for dynamical cosmological constant (``quintessence&#39;&#39;). We take in full consideration the multi-scalar nature of the model, allowing for different initial conditions for the N_f indepen

D. Fliegner, A. Retey, J. A. M. Vermaseren

After an introduction to the sequential version of FORM and the mechanisms behind it we report on the status of our ongoing project of its parallelization. An analysis of the parallel platforms used is given and the structure of a parallel prototype of FORM is explained.

Edgard Gunzig, Alexei Nesteruk, Martin Stokley

We present a simple and self-consistent cosmology with a phenomenological model of quantum creation of radiation and matter due to decay of the cosmological constant $Λ$. The decay drives a non-isentropic inflationary epoch, which exits smoothly to the radiation-dominated era, without reheating, and then evolves to the dust era. The initial vacuum for radiat

N. G. Sarkar, S. Biswas, A. Shaw

We study the behaviour of Dirac current in expanding spacetime with Schr{ö}dinger and de Sitter form for the evolution of the scale-factor. The study is made to understand the particle-antiparticle rotation and the evolution of quantum vacuum leading to particle production in such spacetime.

S. Biswas, A. Shaw, B. Modak

This paper presents the derivation of Schwinger&#39;s gauge invariant result of $Im \cal{L}_{eff}$ upto one loop approximation, for particle production in an uniform electric field through the method of complex trajectory WKB approximation (CWKB). The CWKB proposed by one of the author&#39;s \cite{bis:ijtp} looks upon particle production as due to the motion

E. N. Glass, J. P. Krisch

We consider homothetic maps in a family of spherical relativistic star models. A generalization of Vaidya&#39;s radiating metric provides a fluid atmosphere of radiation and strings. The similarity structure of the string fluid is investigated.

Ken Samuel, Sandra Carberry, K. Vijay-Shanker

We present an empirical investigation of various ways to automatically identify phrases in a tagged corpus that are useful for dialogue act tagging. We found that a new method (which measures a phrase&#39;s deviation from an optimally-predictive phrase), enhanced with a lexical filtering mechanism, produces significantly better cues than manually-selected cu

Mathis Plapp, Jean-Francois Gouyet

We develop mean-field kinetic equations for a lattice gas model of a binary alloy with vacancies (ABv model) in which diffusion takes place by a vacancy mechanism. These equations are applied to the study of phase separation of finite portions of an unstable mixture immersed in a stable vapor. Due to a larger mobility of surface atoms, the most unstable mode

S. Das Sarma, Daw-Wei Wang

We explain quantitatively why resonant Raman scattering spectroscopy, an extensively used experimental tool in studying elementary electronic excitations in doped low dimensional semiconductor nanostructures, always produces an observable peak at the so-called &#34;single particle&#34; excitation although the standard theory predicts that there should be no

J. T. Chalker, Z. Jane Wang

We study spectral properties of the Fokker-Planck operator that represents particles moving via a combination of diffusion and advection in a time-independent random velocity field, presenting in detail work outlined elsewhere [J. T. Chalker and Z. J. Wang, Phys. Rev. Lett. {\bf 79}, 1797 (1997)]. We calculate analytically the ensemble-averaged one-particle

D. V. Shantsev, Y. M. Galperin, T. H. Johansen

The critical state in a superconducting thin circular disk with an arbitrary magnetic field dependence of the critical sheet current, Jc(B), is analyzed. With an applied field Ba perpendicular to the disk, a set of coupled integral equations for the flux and current distributions is derived. The equations are solved numerically, and flux and current profiles

S. D. M. Zwerschke, R. R. Gerhardts

Adopting the mean-field composite fermion picture, we describe the magneto-transport properties of a two-dimensional electron gas with laterally modulated density around filling factor 1/2. The occurrence of a strong positive magnetoresistance at low effective magnetic fields as well as Weiss oscillations, which were observed in recent experiments in such sy

A. V. Dooglav, A. V. Egorov, I. R. Mukhamedshin, A. V. Savinkov

Copper nuclear quadrupole resonance (NQR) and zero field nuclear magnetic resonance (ZFNMR) studies of YBa$_2$Cu$_3$O$_{6.5}$ show that a magnetic phase appears in underdoped 123 superconductors treated in ambient wet air. The studies give convincing evidence that the ``empty&#39;&#39; CuO chains play the role of easy water insertion channels. The reaction o

V. M. Rozenbaum, I. V. Kuzmenko

We investigate anharmonically coupled high- and low-frequency excitations in a planar lattice of adsorbed molecules interacting with phonons of a crystal. Dephasing of high-frequency local vibrations by low-frequency resonance modes is described in terms of temperature Green&#39;s function. The equations obtained are solved, first, with a small ratio of the

Rosario Fazio, G. Massimo Palma, Jens Siewert

The unit of quantum information is the qubit, a vector in a two-dimensional Hilbert space. On the other hand, quantum hardware often operates in two-dimensional subspaces of vector spaces of higher dimensionality. The presence of higher quantum states may affect the accuracy of quantum information processing. In this Letter we show how to cope with {\em quan

G. D&#39;Anna, V. Berseth, L. Forro, A. Erb

Longitudinal and Hall voltages are measured in a clean twinned YBCO single crystal in the liquid and solid vortex phases. For magnetic fields tilted away from the c-axis more than about 2 deg, a scaling law |rho_xy|=A (rho_xx)^beta with beta approx.=1.4 is observed, which is unaffected by the vortex-lattice melting transition. The vortex-solid Hall conductiv

S. Covino, D. Lazzati, G. Ghisellini, P. Saracco

Models for gamma-ray burst afterglows envisage an hyper-relativistic fireball that is decelerated in the ambient medium around the explosion site. This interaction produces a shock wave which amplifies the magnetic field and accelerates electrons to relativistic energies, setting the conditions for an efficient production of synchrotron photons. If produced

A. M. Burdett, I. H. Bond, P. J. Boyle, S. M. Bradbury

We present the results of a search for pulsed TeV emission from the Crab pulsar using the Whipple Observatory&#39;s 10m gamma-ray telescope. The direction of the Crab pulsar was observed for a total of 73.4 hours between 1994 November and 1997 March. Spectral analysis techniques were applied to search for the presence of a gamma-ray signal from the Crab puls

Steven A. Balbus, John F. Hawley

The dynamical state of the solar nebula depends critically upon whether or not the gas is magnetically coupled. The presence of a subthermal field will cause laminar flow to break down into turbulence. Magnetic coupling, in turn, depends upon the ionization fraction of the gas. The inner most region of the nebula ($\lesssim 0.1$ AU) is magnetically well-coup

Ray Jayawardhana, Lee Hartmann, Giovanni Fazio, R. Scott Fisher

A group of young, active stars in the vicinity of TW Hydrae has recently been identified as a possible physical association with a common origin. Given its proximity ($\sim$50 pc), age ($\sim$10 Myr) and abundance of binary systems, the TW Hya Association is ideally suited to studies of diversity and evolution of circumstellar disks. Here we present mid-infr

Slavek M. Rucinski, Wenxian Lu

Radial velocity measurements and simple sine-curve fits to the orbital velocity variations are presented for the second set of ten contact binary systems. Eight systems are of the A-type: AH Aur, CK Boo, DK Cyg, UZ Leo, XZ Leo, V839 Oph, GR Vir and NN Vir. V842 Her is the only W-type, while SV Equ appears to be a semi-detached system seen at a low orbital in

P. P. Avelino, J. H. P. Wu, E. P. S. Shellard

We use the present observed number density of large X-ray clusters to constrain the amplitude of matter density perturbations induced by cosmic strings on the scale of $8 h^{-1}$Mpc ($σ_8$), in both open cosmologies and flat models with a non-zero cosmological constant. We find a slightly lower value of $σ_8$ than that obtained in the context of primordial G

D. A. Baiko, P. Haensel

As pointed out by Kutschera and W{ó}jcik, very low concentration of protons combined with a specific density dependence of effective neutron-proton interaction could lead to a localization of ``proton impurities&#39;&#39; in neutron medium at densities exceeding four times normal nuclear matter density. We study consequences of the localization of protons fo

K. O&#39;Neil, G. Bothun, C. Impey

[annotated] HST WFPC2 images were taken of three LSB dwarf elliptical galaxies in the Virgo cluster. The intent of the observations was to determine the small scale structure in these enigmatic galaxies, and to attempt to learn something about the nature of their giant branch through the detection of luminosity fluctuations. In two of the three studied galax

M. Rowan-Robinson

The star formation history derived from ultraviolet and H$α$ data, without correction for dust extinction, on the one hand, and from far infrared and submillimetre data, on the other, is investigated. The latter estimates are found to be a factor 2-3 higher than the former, consistent with 2/3-3/4 of the uv light in star forming regions being absorbed by dus

P. E. Nissen, D. L. Lambert, F. Primas, V. V. Smith

High resolution (R=110000), very high S/N spectra, centered on the 6707.8A LiI line have been obtained with the ESO Coude Echelle Spectrometer for five, metal-poor (-0.8 < [Fe/H] < -0.6) disk stars in the turnoff region of the HR-diagram. The instrumental and stellar atmospheric line broadening have been determined from two unblended iron lines and used in a

E. Meyer-Hofmeister, F. Meyer

Using the black hole transient X-ray source A0620-00 as an example we study the physical interplay of three theoretical constituents for modelling these transient sources: (1) the advection-dominated accretion flow (ADAF) onto the central black hole, (2) the evaporation of matter from the cool outer disk forming a coronal flow and (3) standard disk evolution

Young-Wook Lee, Suk-Jin Yoon, Hyun-chul Lee, Jong-Hak Woo

Surface temperature distribution of horizontal-branch (HB) stars is very sensitive to age in old stellar systems, which makes it an attractive age indicator. In this paper, we present the recent revision of our model calculations for the HB morphology of globular clusters. The result is more updated version of our earlier models (Lee, Demarque, & Zinn 1994),

A. A. Mikhailov

The connection between the arrival directions of ultrahigh energy cosmic rays by using the EAS array data and point galactic sources of radio-and gamma-radiations, pulsars,is sought. At the mean particle energy of 10^{19} eV the correlation between the particle arrival directions and pulsars located along the magnetic field lines has been found. According to

Licia Verde, Limin Wang, Alan Heavens, Marc Kamionkowski

Since cosmic-microwave-background (CMB) and large-scale-structure (LSS) data will shortly improve dramatically with the Microwave Anisotropy Probe (MAP) and Planck Surveyor, and the Anglo-Australian 2-Degree Field (2dF) and Sloan Digital Sky Survey (SDSS), respectively, it is timely to ask which of the CMB or LSS will provide a better probe of primordial non

Bo-Qiang Ma, Ivan Schmidt, Jian-Jun Yang

It is shown that a perturbative QCD (pQCD) based analysis and the SU(6) quark-diquark model give significant different predictions concerning the flavor and spin structure for the quark distributions of the $Λ$-baryon near $x=1$. Detailed predictions for the ratios $u(x)/s(x)$ of unpolarized quark distributions, $Δs(x)/s(x)$ of valence strange quark, and $Δu

Zahid Zakir

Inhomogeneous Nelson&#39;s diffusion in flat spacetime with a tensor of diffusion can be described as a homogeneous one in a Riemannian manifold with this tensor of diffusion as a metric tensor. The influence of matter to the energy density of the stochastic background (vacuum) is considered. It is shown that gravitation can be represented as inhomogeneity o

I. Devetak, A. LeClair

A scattering scattering description is proposed for a boundary perturbation of a c=1 SL(2,Z) invariant conformal field theory. The bulk massless S-matrices are of the form of Zamolodchikov&#39;s staircase model. Using the boundary version of the thermodynamic Bethe ansatz, we show that the boundary free energy goes through a series of integer valued plateaux

Alejandro Corichi, Andres Gomberoff

We consider 2+1 dimensional gravity with a cosmological constant, and explore a duality that exists between space-times that have the De Sitter group SO(3,1) as its local isometry group. In particular, the Lorentzian theory with a positive cosmological constant is dual to the Euclidean theory with a negative cosmological constant. We use this duality to cons

M. R. Matthews, B. P. Anderson, P. C. Haljan, D. S. Hall

The order parameter of a condensate with two internal states can continuously distort in such a way as to remove twists that have been imposed along its length. We observe this effect experimentally in the collapse and recurrence of Rabi oscillations in a magnetically trapped, two-component Bose-Einstein condensate of ^87Rb.

D. B. Saakian, E. E. Vogel

An approximate method is proposed for investigating complex-temperature properties of real-dimensional spin-glass models. The method uses the complex-temperature data of the ferromagnetic model on the same lattice. The universality line in the complex-temperature space is obtained.

R. N. Mohapatra, F. Olness, R. Stroynowski, V. L. Teplitz

We consider laboratory experiments that can detect stable, neutral strongly interacting massive particles (SIMPs). We explore the SIMP annihilation cross section from its minimum value (restricted by cosmological bounds) to the barn range, and vary the mass values from a GeV to a TeV. We calculate, as a function of the SIMP-nucleon cross section, the minimum

Markus Deserno, Christian Holm, Sylvio May

We investigate the phenomenon of counterion condensation in a solution of highly charged rigid polyelectrolytes within the cell model. A method is proposed which -- based on the charge distribution function -- identifies both the fraction of condensed ions and the radial extension of the condensed layer. Within salt-free Poisson-Boltzmann (PB) theory it repr

S Hollands

We characterise the homogeneous and isotropic gauge invariant and quasifree states for free Dirac quantum fields on Robertson-Walker spacetimes in any even dimension. Using this characterisation, we construct adiabatic vacuum states of order $n$ corresponding to some Cauchy surface. We then show that any two such states (of sufficiently high order) are local

D. Ebert, R. N. Faustov, V. O. Galkin

Exclusive semileptonic decays of B mesons to orbitally excited D mesons are considered beyond the infinitely heavy quark limit in the framework of the relativistic quark model based on the quasipotential approach. This model agrees with the structure of heavy quark mass corrections predicted by the heavy quark effective theory and allows the determination of

D. Bolle, P. Kozlowski

The thermodynamic and retrieval properties of the Ashkin-Teller neural network model storing an infinite number of patterns are examined in the replica-symmetric mean-field approximation. In particular, for linked patterns temperature-capacity phase diagrams are derived for different values of the two-neuron and four-neuron coupling strengths. This model can

Attila Csoto, Karlheinz Langanke

The He3(He4,gamma)Be7 and H3(He4,gamma)Li7 reactions are studied in an extended two-cluster model which contains alpha+h/t and Li6+p/n clusterizations. We show that the inclusion of the Li6+p/n channels can significantly change the zero-energy reaction cross sections, S(0), and other properties of the Be7 and Li7 nuclei, like the quadrupole moments Q. Howeve

Michael Joyce, Kimmo Kainulainen, Tomislav Prokopec

We consider scalar field theory in a changing background field. As an example we study the simple case of a spatially varying mass for which we construct the semiclassical approximation to the propagator. The semiclassical dispersion relation is obtained by consideration of spectral integrals and agrees with the WKB result. Further we find that, as a consequ

Scott Dodelson, Enrique Gaztanaga

The two point angular correlation function is an excellent measure of structure in the universe. To extract from it the three dimensional power spectrum, one must invert Limber&#39;s Equation. Here we perform this inversion using a Bayesian prior constraining the smoothness of the power spectrum. Among other virtues, this technique allows for the possibility

S. Jain

The non-equilibrium dynamics of the strongly diluted random-bond Ising model in two-dimensions (2d) is investigated numerically. The persistence probability, P(t), of spins which do not flip by time t is found to decay to a non-zero, dilution-dependent, value $P(\infty)$. We find that $p(t)=P(t)-P(\infty)$ decays exponentially to zero at large times. Further

S. Biswas, A. Shaw, D. Biswas

In the Starobinsky inflationary model inflation is driven by quantum corrections to the vacuum Einstein equation. We reduce the Wheeler-DeWitt equation corresponding to the Starobinsky model to a Schroedinger form containing time. The Schroedinger equation is solved with a Gaussian ansatz. Using the prescription for the normalization constant of the wavefunc

T K Rai Dastidar, Krishna Rai Dastidar

It has been demonstrated in a recent paper (Mod.Phys.Lett. A13, 1265 (1998); hep-th/9902020) that the existence of a non-thermodynamic arrow of time at the atomic level is a fundamental requirement for conservation of energy in matter-radiation interaction. Since the universe consists of two things only --- energy and massive matter --- we argue that as a co

Takanori Fujiwara, Hiroshi Suzuki, Ke Wu

The axial anomaly in lattice gauge theories has a topological nature when the Dirac operator satisfies the Ginsparg-Wilson relation. We study the axial anomaly in Abelian gauge theories on an infinite hypercubic lattice by utilizing cohomological arguments. The crucial tool in our approach is the non-commutative differential calculus~(NCDC) which makes the L

B. V. Geshkenbein, B. L. Ioffe

We develope the method of improvement of perturbative theory in QCD, applied to any polarization operator. The case of polarization operator Π(q^2), corresponding to the process e^+e^- -> hadrons is considered in details. Using the analytical properties of Π(q^2) and perturbative expansion of Π(q^2) at q^2<0, ImΠ(q^2) at q^2>0 is determined in such a way, th

A. Imaanpur

A 3d topological sigma model describing maps from a 3-manifold Y to a Calabi-Yau 3-fold M is introduced. As the model is topological, we can choose an arbitrary metric on M. Upon scaling up the metric, the path integral by construction localizes on the moduli space of special Lagrangian submanifolds of M. We couple the theory to dynamical gauge fields and di

Daisuke Ida

Static charged perfect fluid distributions have been studied. It is shown that if the norm of the timelike Killing vector and the electrostatic potential have the Weyl-Majumdar relation, then the background spatial metric is the space of constant curvature, and the field equations reduces to a single non-linear partial differential equation. Furthermore, if

D. N. Sheng, Z. Y. Weng

The phase diagram of integer quantum Hall effect is numerically determined in the tight-binding model, which can account for overall features of recently obtained experimental phase diagram. In particular, the quantum Hall plateaus are terminated by two distinct insulating phases, characterized by the Hall resistance with classic and quantized values, respec

Shiping Feng, F. Yuan, W. Q. Yu, P. P. Zhang

Within the t-J model, the c-axis charge dynamics of the copper oxide materials in the underdoped and optimally doped regimes is studied by considering the incoherent interlayer hopping. It is shown that the c-axis charge dynamics is mainly governed by the scattering from the in-plane fluctuation. In the optimally doped regime, the c-axis resistivity is a lin

K. -I. Kondo, Y. Taira

We derive a new version of SU(3) non-Abelian Stokes theorem by making use of the coherent state representation on the coset space $SU(3)/(U(1)\times U(1))=F_2$, the flag space. Then we outline a derivation of the area law of the Wilson loop in SU(3) Yang-Mills theory in the maximal Abelian gauge (The detailed exposition will be given in a forthcoming article

L. Kaplan

A simple argument shows that eigenstates of a classically ergodic system are individually ergodic on coarse-grained scales. This has implications for the quantization ambiguity in ergodic systems: the difference between alternative quantizations is suppressed compared with the $O(\hbar^2)$ ambiguity in the integrable case. For two-dimensional ergodic systems

R. Folman, J. Schmiedmayer, H. Ritsch

Following almost a century of debate on possible `independent of measurement&#39; elements of reality, or `induced&#39; elements of reality - originally invoked as an ad-hoc collapse postulate, we propose a novel line of interference experiments which may be able to examine the regime of induced elements of reality. At the basis of the proposed experiment, l