Masahide Yamaguchi

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We consider hidden sector supersymmetry breakdown in the strongly coupled heterotic E 8 × E 8 theory of Hořava and Witten. Using effective field theory methods in four dimensions, we can show that gravitational interactions induce soft breaking terms in the observable sector that are of order of the gravitiono mass. We apply these methods to the mechanism(More)
We propose a self-consistent scenario of new inflation in supergravity. Chaotic inflation first takes place around the Planck scale, which solves the longevity problem, namely, why the universe can live much beyond the Planck time, and also gives an adequate initial condition for new inflation. Then, new inflation lasts long enough to generate primordial(More)
We study non-Gaussianity, the spectral index of primordial scalar fluctuations and tensor modes in models where fluctuations from the inflaton and the curvaton can both contribute to the present cosmic density fluctuations. Even though simple single-field inflation models generate only tiny non-Gaussianity, if we consider such a mixed scenario, large(More)
We propose a new class of inflation model, G inflation, which has a Galileon-like nonlinear derivative interaction of the form G(ϕ,(∇ϕ)(2))□ϕ in the Lagrangian with the resultant equations of motion being of second order. It is shown that (almost) scale-invariant curvature fluctuations can be generated even in the exactly de Sitter background and that the(More)
We study the effect of primordial isocurvature perturbations on non-Gaussian properties in CMB temperature anisotropies. We consider generic forms of the non-linearity of isocurvature perturbations which can be applied to a wide range of theoretical models. We derive analytical expressions of the bispectrum and the Minkowski Func-tionals for CMB temperature(More)
This paper describes the effect of three new acoustic feature parameters to detect audio source segments that are based on spectral cross-correlation: spectral stability, white noise similarity, and sound spectral shape. These parameters are devised for accurate audio source detection and are used in a pre-processing module for automatic indexing of the(More)