Multiple inflation and the WMAP 'glitches' II. Data analysis and cosmological parameter extraction

Detailed analyses of the WMAP data indicate possible oscillatory features in the primordial curvature perturbation, which moreover appears to be suppressed beyond the present Hubble radius. Such deviations from the usual inflationary expectation of an approximately Harrison-Zeldovich spectrum are expected in the supergravity-based 'multiple inflation' model wherein phase transitions during inflation induce sudden changes in the mass of the inflaton, thus interrupting its slow-roll. In a previous paper we calculated the resulting curvature perturbation and showed how the oscillations arise. Here we perform a Markov Chain Monte Carlo fitting exercise using the 3-year WMAP data to determine how the fitted cosmological parameters vary when such a primordial spectrum is used as an input, rather than the usually assumed power-law spectrum. The 'concordance' LCDM model is still a good fit when there is just a 'step' in the spectrum. However if there is a 'bump' in the spectrum (due e.g. to two phase transitions in rapid succession), the precision CMB data can be well-fitted by a flat Einstein-de Sitter cosmology without dark energy. This however requires the Hubble constant to be h ~ 0.44 which is lower than the locally measured value. To fit the SDSS data on the power spectrum of galaxy clustering requires a ~10% component of hot dark matter, as would naturally be provided by 3 species of neutrinos of mass ~0.5 eV. This CHDM model cannot however fit the position of the baryon acoustic peak in the LRG redshift two-point correlation function. It may be possible to overcome these difficulties in an inhomogeneous Lemaitre-Tolman-Bondi cosmological model with a local void, which can potentially also account for the SN Ia Hubble diagram without invoking cosmic acceleration.Comment: 27 pages, 18 figures (RevTex); Tables revised to include the \chi^2 and "Akaike information criterion" in comparison of cosmological models; Fits to WMAP3 EE spectrum shown; Additional references added; Accepted for publication in in Phys Rev

Search for features in the spectrum of primordial perturbations using Planck and other datasets

We reconstruct the power spectrum of primordial curvature perturbations by applying a well-validated non-parametric technique employing Tikhonov regularisation to the first data release from the Planck satellite. To improve the reconstruction on small spatial scales we include data from the ground-based ACT and SPT experiments, the WiggleZ galaxy redshift survey, the CFHTLenS tomographic weak lensing survey, and spectral analysis of the Lyman-α forest. The reconstructed scalar spectrum (assuming the standard ΛCDM cosmology) is not scale-free but has an infrared cutoff at k ≲ 5 × 10-4 Mpc-1 and several (2-3)σ features, of which two at wavenumber k/Mpc-1 0.0018 and 0.057 had been seen already in WMAP data. A higher significance feature at k ∼ 0.12 Mpc-1 is indicated by Planck data, but may be sensitive to the systematic uncertainty around multipole ℓ ∼ 1800 in the 217×217 GHz cross-spectrum. In any case accounting for the 'look elsewhere' effect decreases its global significance to ∼2σ

Synthesis and Characterization of MnO2 as Electrocatalytic Energy Material for Fuel Cell Electrode

Development Inexpensive  non Pt based  high electrocatalytic energy materials is the need of hour for fuel cell electrode to produce clean alternative green energy from synthesized Bio alcohol  from Biomass.  MnO2 electro synthesized  at different current density is found to be  well performed electrocatalytic material, comparable to Pt, with higher current density, very low over voltage for electrochemical oxidation of methanol . From EIS study, the polarization resistance of the coated MnO2 is found to be much low and electrical double layer capacitance is high, the effect increases with increase in current density of electro deposition. XRD , EDX and AAS analysis confirm the MnO2 deposition, the amount increases with current density. SEM morphology exhibits  enhanced  3D effective substrate area  for electro oxidation of the fuel and a few nano structured grains of deposited MnO2 at higher  current density. The fact  supports an improved electro catalytic property to be applied as high energetic  materials for fuel cell Electrode. Keywords: Electro catalytic ; Energy Material; Fuel Cell: Impedance; Polarization; Electro coatin

Using cosmic neutrinos to search for non-perturbative physics at the Pierre Auger Observatory

The Pierre Auger (cosmic ray) Observatory provides a laboratory for studying fundamental physics at energies far beyond those available at colliders. The Observatory is sensitive not only to hadrons and photons, but can in principle detect ultrahigh energy neutrinos in the cosmic radiation. Interestingly, it may be possible to uncover new physics by analyzing characteristics of the neutrino flux at the Earth. By comparing the rate for quasi-horizontal, deeply penetrating air showers triggered by all types of neutrinos, with the rate for slightly upgoing showers generated by Earth-skimming tau neutrinos, we determine the ratio of events which would need to be detected in order to signal the existence of new non-perturbative interactions beyond the TeV-scale in which the final state energy is dominated by the hadronic component. We use detailed Monte Carlo simulations to calculate the effects of interactions in the Earth and in the atmosphere. We find that observation of 1 Earth-skimming and 10 quasi-horizontal events would exclude the standard model at the 99% confidence level. If new non-perturbative physics exists, a decade or so would be required to find it in the most optimistic case of a neutrino flux at the Waxman-Bahcall level and a neutrino-nucleon cross-section an order of magnitude above the standard model prediction.Comment: 8 pages revtex, 4 eps figure