Pion to upsilon from kappa-deformed Poincare phenomenology

In the extreme rarity of meaningful results for four dimensional physics produced from the mathematically very well developed theory of quantum groups, we present a phenomenological fit to the rotational and radial excitations of mesons with very few parameters, From pion to upsilon, the heavy and light mesons are fitted with the same degree of precision.

Reformulation of variational inequalities on a simplex and compactification of complementarity problems

Many variational inequality problems (VIPs) can be reduced, by a compactification procedure, to a VIP on the canonical simplex. Reformulations of this problem are studied, including smooth reformulations with simple constraints and unconstrained reformulations based on the penalized Fischer-Burmeister function. It is proved that bounded level set results hold for these reformulations under quite general assumptions on the operator. Therefore, it can be guaranteed that minimization algorithms generate bounded sequences and, under monotonicity conditions, these algorithms necessarily nd solutions of the original problem. Some numerical experiments are presented.

Índices geométricos de variabilidade da frequência cardíaca na doença pulmonar obstrutiva crônica

Background: It was already evidenced decreased heart rate variability (HRV) in chronic obstructive pulmonary disease (COPD) patients at rest.Objective: In order to insert new elements in the literature regarding this issue, we evaluated geometric index of HRV in COPD subjects.Method: We analyzed data from 34 volunteers, divided into two groups according to spirometric values: COPD (17 volunteers, FEV1/FVC = 47.3 +/- 10.2; FEV1 = 50.8 +/- 15.7) and control (17 volunteers, FEV1/FVC = 78.8 +/- 10.8; FEV1 = 100.1 +/- 14.7). For analysis of HRV indexes the volunteers remained in the supine position for 30 minutes. We analyzed the following indexes: triangular index (RRtri), triangular interpolation of RR intervals (TINN) and Poincare plot (SD1, SD2 and SD1/SD2). Student t test for unpaired samples and Mann-Whitney test were used for data analysis.Results: We observed statistically significant reductions in geometric indexes in the COPD group: RRtri (0.043 +/- 0.01 vs. 0.059 +/- 0.02; p = 0.018), TINN (105.88 +/- 51.82 vs. 151.47 +/- 49.9; p=0.014), SD1 (9.76 +/- 4.66 vs. 14.55 +/- 6.04; p = 0.014) and SD2 (34.86 +/- 17.02 vs. 51.51 +/- 18.38; p = 0.010). SD1/5D2 (0.30 +/- 0.11 vs. 0.28 +/- 0.07; p = 0.605) were not significantly different between groups. Patients with COPD presented a visual analysis of Poincare plot of lower dispersion of RR intervals both beat to beat and the long term.Conclusion: Subjects with COPD present reduction of geometric indexes of HRV, indicating reduced heart rate variability. (C) 2010 Sociedade Portuguesa de Pneumologia. Published by Elsevier Espana, S.L. All rights reserved.

Periodic perturbations of quadratic planar polynomial vector fields

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Large amplitude oscillations for a class of symmetric polynomial differential systems in R³

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Self-energies for interacting fields with a compactified spatial dimension

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Five-dimensional f(R) braneworld models

After incorporating f(R) gravity into the general braneworld sum rules scope, it is shown that some particular class of warped five-dimensional nonlinear braneworld models, which may be interesting for the hierarchy problem solution, still require a negative tension brane. For other classes of warp factors (suitable and not suitable for approaching the hierarchy problem) any negative brane tension in the compactification scheme is not necessary. In this vein, it is argued that, in the bulk f(R) gravity context, some types of warp factors may be useful for approaching the hierarchy problem and for evading the necessity of a negative brane tension in the compactification scheme.

STABLE PIECEWISE POLYNOMIAL VECTOR FIELDS

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Regular and chaotic interactions of two BPS dyons at low energy

We identify and analyze quasiperiodic and chaotic motion patterns in the time evolution of a classical, non-Abelian Bogomol'nyi-Prasad-Sommerfield (BPS) dyon pair at low energies. This system is amenable to the geodesic approximation which restricts the underlying SU(2) Yang-Mills-Higgs dynamics to an eight-dimensional phase space. We numerically calculate a representative set of long-time solutions to the corresponding Hamilton equations and analyze quasiperiodic and chaotic phase space regions by means of Poincare surfaces of section, high-resolution power spectra and Lyapunov exponents. Our results provide clear evidence for both quasiperiodic and chaotic behavior and characterize it quantitatively. Indications for intermittency are also discussed.

Massive superstring vertex operator in D=10 superspace

Using the pure spinor formalism for the superstring, the vertex operator for the first massive states of the open superstring is constructed in a manifestly super-Poincare covariant manner. This vertex operator describes a massive spin-two multiplet in terms of ten-dimensional superfields.

Superstrings in graviphoton background and N=1/2+3/2 supersymmetry

Motivated by Ooguri and Vafa, we study superstrings in flat R-4 in a constant self-dual graviphoton background. The supergravity equations of motion are satisfied in this background which deforms the N = 2 d = 4 flat space super-Poincare algebra to another algebra with eight supercharges. A D-brane in this space preserves a quarter of the supercharges; i.e. N = 1/2 supersymmetry is realized linearly, and the remaining N = 3/2 supersymmetry is realized nonlinearly. The theory on the brane can be described as a theory in noncommutative superspace in which the chiral fermionic coordinates theta(alpha) of N = 1 d = 4 superspace are not Grassman variables but satisfy a Clifford algebra.

Covariant multiloop superstring amplitudes

In this article, the multiloop amplitude prescription using the super-Poincare invariant pure spinor formalism for the superstring is reviewed. Unlike the RNS prescription, there is no sum over spin structures and surface terms coming from the boundary of moduli space can be ignored. Massless N-point multiloop amplitudes vanish for N < 4, which implies (with two mild assumptions) the perturbative finiteness of superstring theory. Also, R-4 terms receive no multiloop contributions in agreement with the Type IIB S-duality conjecture of Green and Gutperle. (c) 2005 Published by Elsevier SAS on behalf of Academie des sciences.

Cosmological term and fundamental physics

A nonvanishing cosmological term in Einstein's equations implies a nonvanishing spacetime curvature even in the absence of any kind of matter. It would, in consequence, affect many of the underlying kinematic tenets of physical theory. The usual commutative spacetime translations of the Poincare group would be replaced by the mixed conformal translations of the de Sitter group, leading to obvious alterations in elementary concepts such as time, energy and momentum. Although negligible at small scales, such modifications may come to have important consequences both in the large and for the inflationary picture of the early Universe. A qualitative discussion is presented, which suggests deep changes in Hamiltonian, Quantum and Statistical Mechanics. In the primeval universe as described by the standard cosmological model, in particular, the equations of state of the matter sources could be quite different from those usually introduced.

Charges and fluxes in Maxwell theory on compact manifolds with boundary

We investigate the charges and fluxes that can occur in higher-order Abelian gauge theories defined on compact space-time manifolds with boundary. The boundary is necessary to supply a destination to the electric lines of force emanating from brane sources, thus allowing non-zero net electric charges, but it also introduces new types of electric and magnetic flux. The resulting structure of currents, charges, and fluxes is studied and expressed in the language of relative homology and de Rham cohomology and the corresponding abelian groups. These can be organised in terms of a pair of exact sequences related by the Poincare-Lefschetz isomorphism and by a weaker flip symmetry exchanging the ends of the sequences. It is shown how all this structure is brought into play by the imposition of the appropriately generalised Maxwell's equations. The requirement that these equations be integrable restricts the world-volume of a permitted brane (assumed closed) to be homologous to a cycle on the boundary of space-time. All electric charges and magnetic fluxes are quantised and satisfy the Dirac quantisation condition. But through some boundary cycles there may be unquantised electric fluxes associated with quantised magnetic fluxes and so dyonic in nature.

Pure spinor formalism as an N=2 topological string

Following suggestions of Nekrasov and Siegel, a non-minimal set of fields are added to the pure spinor formalism for the superstring. Twisted (c) over cap = 3 N = 2 generators are then constructed where the pure spinor BRST operator is the fermionic spin-one generator, and the formalism is interpreted as a critical topological string. Three applications of this topological string theory include the super-Poincare covariant computation of multiloop superstring amplitudes without picture-changing operators, the construction of a cubic open superstring field theory without contact-term problems, and a new four-dimensional version of the pure spinor formalism which computes F-terms in the spacetime action.