Primordial Black Holes from Volkov-Akulov-Starobinsky Supergravity

We study the formation of primordial black holes (PBH) in the Starobinsky supergravity coupled to the nilpotent superfield describing Volkov-Akulov goldstino. By using the no-scale Kahler potential and a polynomial superpotential, we find that under certain conditions our model can describe effectively single-field inflation with the ultra-slow-roll phase that appears near a critical (near-inflection) point of the scalar potential. This can lead to the formation of PBH as part of (or whole) dark matter, while keeping the inflationary spectral tilt and the tensor-to-scalar ratio in good agreement with the current cosmic microwave background (CMB) bounds. After inflation, supersymmetry is spontaneously broken at the inflationary scale with the vanishing cosmological constant.

Automated summary

By using the Starobinsky supergravity theory and the nilpotent superfield describing Volkov-Akulov goldstino, we find that our model can effectively describe single-field inflation with the ultra-slow-roll phase near a critical point. This can lead to the formation of primordial black holes (PBH) as part of or the entirety of dark matter, while maintaining consistency with the cosmic microwave background (CMB) constraints on the spectral tilt and tensor-to-scalar ratio. After inflation, supersymmetry is spontaneously broken at the inflationary scale, resulting in a vanishing cosmological constant.