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There is a missing energy problem in cosmology: the total energy density of the Universe, based on a wide range of observations, is much greater than the energy density contributed by all baryons, neutrinos, photons, and dark matter. Deepening this mystery are the recent observations of type 1a supernovae which suggest that the expansion rate of the Universe is accelerating. One possible resolution is the existence of a cosmological constant which fills this energy gap. However, a logical alternative is "quintessence," a time-dependent, spatially inhomogeneous, negative pressure energy component which drives the cosmic expansion. This lecture will serve as an introduction to the quintessence cosmological scenario.

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We present a review of some applications of quantum field theory in the physics of condensed matter stressing the extremely fruitful interaction between these two areas. The examples considered include the Kondo effect, Polymers, High-Tc superconductivity and Spin Glasses.

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In this talk I first present an overview of Standard Model predictions for CP violation in the neutral B-meson sector. Then, I present a status report from the <img src="http:/img/fbpe/bjp/v30n2/sbgtra.gif" border="0"> experiment at the Stanford Linear Accelerator Center which has been designed especially to measure time-dependent asymmetries whose interpretation in the Standard Model is directly related to the parameters of the Cabibbo-Kobayashi-Maskawa mixing matrix.

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These lectures provide an elementary introduction to Chern Simons Gravity and Supergravity in d = 2n + 1 dimensions.

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There are many theoretical arguments indicating that there should be new Physics around the TeV scale which can be discovered in the next decade. We briefly review some of the possible scenarios which give rise to a plethora of new signals at collider experiments.

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A strict proof of equivalence between Duffin-Kemmer-Petiau (DKP) and Klein-Gordon (KG) theories is presented for physical S-matrix elements in the case of charged scalar particles interacting in minimal way with an external or quantized electromagnetic field. First, Hamiltonian canonical approach to DKP theory is developed in matrix form. The theory is then quantized through the construction of the generating functional for Green functions (GF) and the physical matrix elements of S-matrix are proved to be relativistic invariants. The equivalence between both theories is then proved using the connection between GF and the elements of S-matrix in reduction formulas of Lehmann, Symanzik, Zimmermann.

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We review the role of the QCD vacuum structure in the determination of the properties of states and processes occurring in the confinement regime of QCD. The vacuum correlation model of non-perturbative QCD is mentioned as a bridge between the fundamental theory and the description of the experiments. The model of the stochastic vacuum provides the framework in which a simple and effective description of the high-energy pp and p data can be given, leading to a determination of relevant parameters of non-perturbative QCD and to a good description of the data. A slow increase of the hadronic radii with the energy accounts for the energy dependence of all observables.

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From a sample of 1240 ± 51 D+ <FONT FACE=Symbol>®</font> pi- pi+ pi+ we find gamma(D+ -> pi- pi+ pi+)/gamma(D+ -> K- pi+ pi+) = 0:0329 ± 0:0015 <img src="http:/img/fbpe/bjp/v30n2/10eq01.gif" border="0" align="absmiddle">. Using a coherent amplitude analysis to t the Dalitz plot of this decay, we find strong evidence that a scalar resonance of mass 483<img src="http:/img/fbpe/bjp/v30n2/10eq02.gif" border="0" align="absmiddle"> ± 17 MeV/c² and width 338<img src="http:/img/fbpe/bjp/v30n2/10eq03.gif" border="0" align="absmiddle"> ± 21 MeV/c² produces a decay fraction of approximately one half.

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The geometric language of General Relativity is not normally related to Condensed Matter (CM) Physics since it is the electromagnetic and not the gravitational interaction that dominates the physics of CM systems. What points in common would then CMP have with Cosmology and the dynamics of objects in a gravitational field? There is at least one that is very important: topological defects formed in symmetry breaking phase transitions. To explore the similarities and differences here has been a very fruitful experience for both sides. On one hand, topological defects in solids started to be described by a gravity-like theory including torsion and, on the other hand, experiments have been proposed and performed in CM systems with the purpose of testing cosmological theories. Some examples are: 1) Landau levels and the Aharonov-Bohm effect of electrons moving in a crystal containing a screw dislocation can be described in a simple way in a geometric formalism; 2) closed timelike curves have been proposed in the vicinity of vortices in superfluid Helium; 3) Kibble mechanism, for the generation of topological defects, has been experimentally verified in liquid crystals. In summary, Condensed Matter Physics with its rich diversity of systems and phenomena and of relatively easy access to experiments, appears as a laboratory for testing hypotheses of gravitational theory and cosmology involving topological defects. In this work I summarize recent results in this interface area focusing mainly in the results obtained by our research group.

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New experiments are discussed on measuring the Casimir force between metallic surfaces. One of them uses torsion pendulum and the other one - atomic force microscope. The claimed agreement of experimental data with a theory is analyzed. A 5% level of agreement obtained with a torsion pendulum is shown to be in contradiction with the values of surface roughness, finite conductivity and temperature corrections to the Casimir force. A 1% agreement (at the closest separations) obtained with an atomic force microscope is confirmed by the use of more exact theory taking into account higher order surface roughness and conductivity corrections.

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An overview of the LHCb experiment, which has been aprooved by CERN in september 1998, is presented [1].

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We argue that the Copenhagen interpretation of quantum mechanics cannot be applied to quantum cosmology. Among the alternative interpretations, we choose to apply the Bohm-de Broglie interpretation of quantum mechanics to canonical quantum cosmology. For minisuperspace models, we show that there is no problem of time in this interpretation, and that quantum effects can avoid the initial singularity, create inflation and isotropize the Universe. For the general case, it is shown that, irrespective of any regularization or choice of factor ordering of the Wheeler-DeWitt equation, the unique relevant quantum effect which does not break spacetime is the change of its signature from lorentzian to euclidean. The other quantum effects are either trivial or break the four-geometry of spacetime. A Bohm-de Broglie picture of a quantum geometrodynamics is constructed, which allows the investigation of these latter structures.

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Present data from various neutrino experiments are strongly suggesting the existence of neutrino mass and flavor mixing. We review the present status of neutrino oscillation search and various neutrino anomalies and their possible interpretations in terms of oscillation induced by neutrino mass and flavor mixing.

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We present some aspects of the study of quantum integrable systems and its relation to quantum groups.

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This paper describes the Forward Proton Detector (FPD) proposed to be implemented in the Dzero Detector, as a set of sub-detectors consisting of 18 Roman Pots. We call attention to the importance of the studies of the diffractive region of the strong interactions.

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Recent observations indicate that the expansion of the Universe is accelerating. This suggests the existence of some kind of exotic matter with negative pressure. The simplest possibility is a cosmological constant but there are alternatives, as for instance an evolving scalar field. In this paper we explore constraints from lensing statistics and high-z type Ia Supernovae on some of these alternatives.

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Thin film Al/Sb2Pb1Se7/Al, MGM, sandwiched structures, prepared using thermal evaporation technique have been studied. The DC measurements at low electric field suggest that the electrical transport is governed by space charge limited conduction (SCLC) mechanism. The detailed analysis of current-voltage limited conduction (SCLC) mechanism characteristics on the basis of SCLC theory reveals the presence of uniformly distributed trap density of the order of 10(23) m-3 eV-1 with average activation energy 0.48 eV.

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We present new experimental atomic transition values for the atomic emission spectrum of doubly ionized argon, Ar III. In this work we studied 3s² 3p4 - 3s² 3p³ 3d, 3s² 3p4 - 3s² 3p³ 4s, 3s² 3p4 - 3s² 3p³ 4d, 3s² 3p4 - 3s² 3p³ 5s, 3s² 3p³ 4p, and 3s² 3p³ 4p transition arrays and 196 lines were identified as new atomic transitions between levels of these configurations. The experimental data were obtained from a capillary-discharge tube. The identifications are supported by multiconfiguration Hartree-Fock relativistic calculations.

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We determine the mobility of positive and negative charge carriers in a soluble green-emitting alternating block copolymer with a methoxy bi-substituted conjugated segment. The negative charge carrier mobility of 6 × 10-11 cm /V.s is directly determined using space-charge-limited current analytical expressions. Positive charge carrier transport is also space-charge-limited, with a mobility of 1 × 10-8 eV. The electron trap distribution is exponential, with a characteristic energy of ~ 0.12 eV. A hole trap with energy ~ 0.4 eV was observed. This copolymer is used as emissive material in organic light-emitting diodes that present brightness of ~ 900 dc/m² at 12.5 V.

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We analyse the planetary perihelion precession and the deffection of light in the Schwarzschild field modified by a conical defect. By using observational results from solar system tests of general relativity, we obtain limits on the conical defect parameter <img src="http:/img/fbpe/bjp/v30n2/ses.gif">. For the physical case of a cosmic string the quoted limits are one and three orders weaker than the cosmological bounds.

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The space-dependent electric potential equations were determined by solution of non-linear Poisson-Boltzmann equation, which decribes an erythrocyte membrane model which takes into account the charges of molecules associated with lipidic bilayer (glycocalyx molecules, outer side, and spectrin, inner side). It was assumed that on both sides of the membrane the charges are homogeneously distributed. Therefore, the potential was dependent on the z-coordinate only. Thus, we obtained the potential profile curve. The results are compared to previous ones obtained from more simple membrane model (Bioelectroch. Bioenerg. 1993, 32:305-315).

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We discuss the occurrence of Bose-Einstein condensation in systems of noninteracting charged particles in three and one dimensions and in presence of an external magnetic field. In the one dimensional, as well as in the magnetic field cases, although not a critical temperature, a characteristic temperature can be found, corresponding to the case in which the ground state density becomes a macroscopic fraction of the total density. The case of relativistic charged scalar and vector particles is studied. The results give support to the existence of superconductivity in extremely strong magnetic fields, and lead to the prediction of superconductive-ferromagnetic behavior in the vector field case, which might be of interest in condensed matter as well as in cosmology. Some features of the magnetization in the early universe are conjectured.

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The existence of the vector supersymmetry is analysed within the context of the finite temperature Chern-Simons theory.

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In this work we have studied the dispersion of the disorder-induced (D) and the second-order (G') Raman bands in single wall carbon nanotubes using several laser excitation energies (E laser) in the range 1.5-3.0 eV. An anomalous step-like behavior was observed in the E laser dependence of the G'-band frequency. This result is interpreted as a manifestation of the one-dimensional (1D) behavior of the phonon spectrum in carbon nanotubes.

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We use the self-consistent harmonic approximation (SCHA) to study static properties of the two-dimensional quantum Heisenberg model with easy-axis anisotropy. We calculate the critical temperature as a function of the spin value, and compare with classical results. Specifically, we compare how the ratio of critical temperatures varies as a function of the spin S in the quantum and classical cases, for afixed anisotropy parameter. We see that, for values of spin near 5/2, the classical result approximates to the quantum results and the classical calculation is justified. We have also studied the behavior of the magnetization for very small anisotropies. We have shown that our magnetization curves do not present a plateau in the limit of very small anisotropies, as predicted by the real-space renormalization-group calculations.

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We report elastic differential cross sections (DCS) for the scattering of electron by H2, CH4, C2H4, SiH4, and H2O in the 5 to 20 eV energy range. These cross sections were obtained using the Schwinger variational principle. In our procedures the scattering wave function is expanded as a combination of plane waves. In the present implementation the exchange potential and polarization effects are not considered and all results are obtained at the static level of approximation. For all molecules, except H2, our calculated DCS agree reasonably well with avaliable experimental data and with other theoretical results (obtained at the static-exchange level of approximation). Our study suggests that the Schwinger variational principle with plane wave expansion may become an efficient method for studying electron-molecule scattering.

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In this paper we obtain the Lie symmetries and the Noether symmetries for several physical systems, all of them involving a charged particle in the presence of some electromagnetic field. We also obtain first integrals for these systems and discuss briefly their Lie algebra. In some examples we discuss their integrability.

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Nonlinear dispersionless equations arise as the dispersionless limit of well know integrable hierarchies of equations or by construction, such as the system of hydrodynamic type. Some of these equations are integrable in the Hamiltonian sense and appear in the study of topological minimal models. In the first part of the review, we will give a brief introduction to integrable models, mainly its Lax representation. Then, we will introduce the dispersionless limit and show some of our results concerning the two-component hyperbolic system of equations such as the polytropic gas and Born-Infeld equations.