A Physical Picture of Bispectrum Baryon Acoustic Oscillations in the Interferometric Basis
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A Physical Picture of Bispectrum Baryon Acoustic Oscillations in the Interferometric Basis

  • Author(s): Child, Hillary L
  • Slepian, Zachary
  • Takada, Masahiro
  • et al.
Abstract

We present a picture of the matter bispectrum in a novel "interferometric" basis designed to highlight interference of the baryon acoustic oscillations (BAO) in the power spectra composing it. Triangles where constructive interference amplifies BAO provide stronger cosmic distance constraints than triangles with destructive interference. We show that the amplitude of the BAO feature in the full cyclically summed bispectrum can be decomposed into simpler contributions from single terms or pairs of terms in the perturbation theory bispectrum, and that across large swathes of our parameter space the full BAO amplitude is described well by the amplitude of BAO in a single term. The dominant term is determined largely by the $F^{(2)}$ kernel of Eulerian standard perturbation theory. We present a simple physical picture of the BAO amplitude in each term; the BAO signal is strongest in triangle configurations where two wavenumbers differ by a multiple of the BAO fundamental wavelength.

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