Quantum loop effects on the power spectrum and constraints on primordial black holes

Understand

We present a detailed exposition on the prospects of the formation of Primordial Black Holes (PBHs) during Slow Roll (SR) to Ultra Slow Roll (USR) sharp transitions in the framework of single-field inflation.

• We use an effective field theory (EFT) approach in order to keep the analysis model-independent and applicable to both the canonical and non-canonical cases.
• We show in detail how renormalizing the power spectrum to one loop order in $P(X,\phi)$ theories severely limits the prospects for PBH formation in a single-field inflationary framework.
• We demonstrate that for the allowed range of effective sound speed, $1<c_s<1.17$, the consistency of one-loop corrected power spectrum leaves a small window for black hole masses, $M_{\rm PBH}\sim \mathcal{O}(10^2-10^3)$gm to have sufficient e-foldings, $\Delta {\cal N}_{\rm Total}\sim {\cal O}(54-59)$ for inflation.