PIRSA:24020047

Axionic Blue Isocurvature Perturbations: Generation and Astrophysical Detection Forecasts

Chaitanya, S. (2024). Axionic Blue Isocurvature Perturbations: Generation and Astrophysical Detection Forecasts. Perimeter Institute. https://pirsa.org/24020047

Chaitanya, Sai. Axionic Blue Isocurvature Perturbations: Generation and Astrophysical Detection Forecasts. Perimeter Institute, Feb. 08, 2024, https://pirsa.org/24020047 

          @misc{ pirsa_PIRSA:24020047,
            doi = {10.48660/24020047},
            url = {https://pirsa.org/24020047},
            author = {Chaitanya, Sai},
            keywords = {Cosmology},
            language = {en},
            title = {Axionic Blue Isocurvature Perturbations: Generation and Astrophysical Detection Forecasts},
            publisher = {Perimeter Institute},
            year = {2024},
            month = {feb},
            note = {PIRSA:24020047 see, \url{https://pirsa.org}}
          }

Sai Chaitanya

University of Wisconsin–Madison

Talk number
PIRSA:24020047
Collection
Talk Type
Subject
Abstract

When additional degrees of freedom are considered during inflation, a crucial aspect of early universe physics emerges: the generation of isocurvature quantum fluctuations. In this talk, we will present generation and detection forecast for axionic blue-tilted isocurvature power spectra. The large blue-tilt readily evades current CMB bounds. Following a brief review, we will discuss a SUSY-embedded axion model which generates a strongly blue tilted (nI~4) isocurvature spectrum during inflation when the quantum modes are starting to be underdamped ( m/H > 3/2 ). Interestingly, there exist parametric regions with strong resonant spectral behavior that lead to rich isocurvature spectral shapes and large amplitude enhancements. These can be particularly interesting with observational consequences, in relation to the generation of PBH and GWs. The isocurvature spectral tilt is directly linked to the axion mass during inflation. Detecting blue-tilted isocurvatures can offer indirect evidence of a weakly interacting dark matter-like spectator field beyond conventional thermal-relic scenarios. Lastly, we will examine and forecast constraints for experiments such as Euclid (upcoming) and MegaMapper (proposed) using EFTofLSS based perturbative techniques. In the process we will comment upon the consistent renormalization requirements for mixed adiabatic and blue isocurvature primordial spectra.

---

Zoom link