We use a set of numerical N -body simulations to study the large-scale behavior of the reduced bispectrum of dark matter and compare the results with the second-order perturbation theory and the halo models for different halo mass functions. We find that the second-order perturbation theory (PT2) agrees with the simulations fairly well on large scales of k < 0.05 hMpc, but it shows a signature ...

A generalization of the Woodward's theorem is applied to the case of random signals jointly modulated in amplitude and frequency. This yields the signal spectrum and a rather robust estimate of the bispectrum. Furthermore, higher order statistics that quantify the amount of energy in the signal due to nonlinearities, e.g., wave–wave interaction in the case of water waves, can be inferred. Consi...

Acoustic noise generated by vessel motion in the test range on a river is the subject of this paper. The hydroacoustic field of the vessel is analyzed using different methods. The analysis was performed in time and frequency domain. The acoustic signals are analyzed using classical concept of the spectral analysis, parametric models of random processes and bispectrum analysis. Particular intere...

The method proposed in this chapter is making use of the bispectrum transformation to estimate the level of integration of a fractionally integrated time series. Bispectrum transformation transforms the series into a two dimensional frequency space, and thus has higher information content compared to the Geweke-Porter-Hudak method. The bispectrum method is an alternative to the recently propose...

Baryonic oscillations in the galaxy power spectrum have been studied as a way of probing dark-energy models. While most studies have focused on spectroscopic surveys at high redshift, large multi-color imaging surveys have already been planned for the near future. In view of this, we study the prospects for measuring baryonic oscillations from angular statistics of galaxies binned using photome...

In this paper, we discuss the potential importance of measuring the CMB anistropy bispectrum. We develop a formalism for computing the bispectrum and for measuring it from microwave background maps. As an example, we compute the bispectrum resulting from the 2nd order Rees-Sciama effect, and find that is undetectable with current and upcoming missions. While this effect is undetectable, we show...

We perform a frequentist analysis of the bispectrum of WMAP first year data. We find clear signal domination up to l ≈ 200, with overall consistency with Gaussianity, except for the following features. There is a flat patch (i.e. a low χ region) in the same-l components of the bispectrum spanning the range l = 32 − 62; this may be interpreted as ruling out Gaussianity at the 99.6% confidence le...

We calculate the bispectrum of the Cosmic Microwave Background (CMB) temperature anisotropies induced by the second-order fluctuations in the Boltzmann equation. In this paper, which is one of a series of papers on the numerical calculation of the bispectrum from the second-order fluctuations, we consider the terms that are products of the first-order perturbations, and leave intrinsically seco...

We calculate the bispectrum of the gravitational field fluctuations generated during warm inflation, where dissipation of the vacuum potential during inflation is the mechanism for structure formation. The bispectrum is non–zero because of the self–interaction of the scalar field. We compare the predictions with those of standard, or ‘supercooled’, inflationary models, and consider the detectab...