Paolo Cea

Ellipsoidal Universe Can Solve The CMB Quadrupole Problem

The recent 3 yr Wilkinson Microwave Anisotropy Probe data have confirmed the anomaly concerning the low quadrupole amplitude compared to the best-fit Lambda-cold dark matter prediction. We show that by allowing the large-scale spatial geometry of our universe to be plane symmetric with eccentricity at decoupling or order 10(-2), the quadrupole amplitude can be drastically reduced without affecting higher multipoles of the angular power spectrum of the temperature anisotropy.

Cosmic microwave background quadrupole and ellipsoidal universe

Recent Wilkinson Microwave Anisotropy Probe (WMAP) data confirm the cosmic microwave background (CMB) quadrupole anomaly. We further elaborate our previous proposal that the quadrupole power can be naturally suppressed in axis-symmetric universes. In particular, we discuss in greater detail the CMB quadrupole anisotropy and considerably improve our analysis. As a result, we obtain tighter constraints on the direction of the axis of symmetry as well as on the eccentricity at decoupling. We find that the quadrupole amplitude can be brought in accordance with observations with an eccentricity at decoupling of about 0.64x10{sup -2}. Moreover, our determination of the direction of the symmetry axis is in reasonable agreement with recent statistical analyses of cleaned CMB temperature fluctuation maps obtained by means of improved internal linear combination methods as galactic foreground subtraction technique.

Ellipsoidal universe can solve the cosmic microwave background quadrupole problem.

The recent 3 yr Wilkinson Microwave Anisotropy Probe data have confirmed the anomaly concerning the low quadrupole amplitude compared to the best-fit Lambda-cold dark matter prediction. We show that by allowing the large-scale spatial geometry of our universe to be plane symmetric with eccentricity at decoupling or order 10(-2), the quadrupole amplitude can be drastically reduced without affecting higher multipoles of the angular power spectrum of the temperature anisotropy.

Testing the Isotropy of the Universe with Type Ia Supernovae

We analyze the magnitude-redshift data of type Ia supernovae included in the Union and Union2 compilations in the framework of an anisotropic Bianchi type I cosmological model and in the presence of a dark energy fluid with anisotropic equation of state. We find that the amount of deviation from isotropy of the equation of state of dark energy, the skewness �, and the present level of anisotropy of the large-scale geometry of the Universe, the actual shear �0, are constrained in the ranges −0.16 . � . 0.12 and −0.012 . �0 . 0.012 (1� C.L.) by Union2 data. Supernova data are then compatible with a standard isotropic universe (� = �0 = 0), but a large level of anisotropy, both in the geometry of the Universe and in the equation of state of dark energy, is allowed.

Decay constants of heavy mesons from a QCD relativistic potential model

Abstract We compute masses and leptonic decay constants of charmed and beauty pseudoscalar and vector mesons by using a QCD-inspired relativistic potential model. We obtain results in agreement with the available experimental data; as for the pseudoscalar meson decay constants, we predict fD=1.38fπ,fDs=1.51fπ,fB=1.75fπ,fBs=1.86f π.

Inflation-produced magnetic fields in nonlinear electrodynamics

We study the generation of primeval magnetic fields during inflation era in nonlinear theories of electrodynamics. Although the intensity of the produced fields strongly depends on characteristics of inflation and on the form of electromagnetic Lagrangian, our results do not exclude the possibility that these fields could be astrophysically interesting.

Dual superconductivity in the SU(2) pure gauge vacuum: A lattice study.

We investigate the dual superconductivity hypothesis in pure SU(2) lattice gauge theory. We focus on the dual Meissner effect by analyzing the distribution of the color fields due to a static quark-antiquark pair. We find evidence of the dual Meissner effect both in the maximally Abelian gauge and without gauge fixing. We measure the London penetration length. Our results suggest that the London penetration length is a physical gauge-invariant quantity. We put out a simple relation between the penetration length and the square root of the string tension. We find that our estimation is quite close to the extrapolated continuum limit available in the literature. A remarkable consequence of our study is that an effective Abelian theory can account for the long range properties of the SU(2) confining vacuum.

Analytic continuation from imaginary to real chemical potential in two-color QCD

The method of analytic continuation from imaginary to real chemical potential is one of the most powerful tools to circumvent the sign problem in lattice QCD. Here we test this method in a theory, two-color QCD, which is free from the sign problem. We find that the method gives reliable results, within appropriate ranges of the chemical potential, and that a considerable improvement can be achieved if suitable functions are used to interpolate data with imaginary chemical potential.

Inflation-Produced Magnetic Fields in R^n F^2 and I F^2 models

We reanalyze the production of seed magnetic fields during inflation in

Abelian chromomagnetic fields and confinement

(R/{m}^{2}{)}^{n}{F}_{\ensuremath{\mu}\ensuremath{\nu}}{F}^{\ensuremath{\mu}\ensuremath{\nu}}