Do we really gain from field-level inference? A comparison with joint power spectrum and bispectrum analysis

Kazuyuki Akitsu (KEK, Tsukuba)

Sep 22. 2025, 14:20 — 14:40

We show that, within the perturbative regime, the constraining power of field-level inference on cosmological parameters is comparable to that of a joint power spectrum and bispectrum analysis based on the same perturbative model. We further examine the role of the field-level likelihood and demonstrate that using a Gaussian field-level likelihood to fit mock data with non-Gaussian noise leads to significant biases in the inferred cosmological parameters. In contrast, the joint power spectrum and bispectrum analysis can reliably recover the input cosmological parameters under a Gaussian likelihood, owing to the central limit theorem. These results underscore that the success of field-level inference critically depends on employing the correct likelihood, which may be the main obstacle to extending this method to smaller scales, even within the perturbative regime.

Further Information
Venue:
ESI Boltzmann Lecture Hall
Associated Event:
Putting the Cosmic Large-scale Structure on the Map: Theory Meets Numerics (Workshop)
Organizer(s):
Oliver Hahn (U of Vienna)
Cornelius Rampf (RBI, Zagreb)
Cora Uhlemann (Bielefeld U)