Accurate estimators of power spectra inN-body simulations

Accurate estimators of power spectra in N -body simulations

A method to rapidly estimate the Fourier power spectrum of a point distribution is presented. This method relies on a Taylor expansion of the trigonometric functions. It yields the Fourier modes from a number of FFTs, which is controlled by the order N of the expansion and by the dimension D of the system. In three dimensions, for the practical value N = 3, the number of FFTs required is 20. We...

Temperature dependence of infrared reflectance spectra of InN

To investigate both the optical and electrical properties of InN, we have measured the infrared reflectance spectra of InN thin films and performed the fitting analyses of the infrared spectra to obtain not only phonon frequencies and the damping factors but also the carrier concentration of InN. In this paper, we extend the aim of those analyses to the electron mobility and demonstrate that th...

Permuted Estimators for Regenerative Simulations

In a previous paper we introduced a new variance-reduction technique for regenerative simulations based on permuting regeneration cycles. In this paper we apply this idea to large classes of other estimators. In particular, we derive permuted versions of likelihood-ratio derivative estimators for steady-state performance measures, importance-sampling estima-tors of the mean cumulative reward un...

accurate-mass spectra

Understanding the PSCz Galaxy Power Spectrum with N-body Simulations

By comparing the PSCz galaxy power spectrum with the results of nested pure darkmatter N-body simulations, we try to understand how infrared-selected galaxies populate dark-matter haloes, paying special attention to the method of halo identification in the simulations. We thus test the hypothesis that baryonic physics negligibly affects the distribution of galaxies down to the smallest scales y...