Stochastic Dark Matter from Curvature Perturbations

Journal Article · 12 March 2025 · Physical Review Letters

DOI: https://doi.org/10.1103/PhysRevLett.134.101005 · OSTI ID:2530760

Garani, Raghuveer ; Redi, Michele ; Tesi, Andrea

We investigate the production of dark matter from metric perturbations produced during inflation or in standard cosmology. Perturbations break Weyl flatness of the Friedmann-Lemaître-Robertson-Walker metric, allowing conformally coupled fields—in particular, fermions studied here—to be produced even when their mass is negligible. Particle production can be computed by studying the Bogoliubov transformation induced by the stochastic background. For perturbations generated during inflation, we present a closed formula for the resulting abundance of particles that depends solely on the power spectrum of curvature perturbations at the end of inflation. This production mechanism can be dominant especially if the amplitude of curvature perturbations is enhanced for modes that exit the horizon toward the end of inflation. In the simplest scenario, the critical dark matter abundance is reproduced for $M\gtrsim {10}^6\mathrm{GeV}$ . Published by the American Physical Society 2025

• Sponsoring Organization: USDOE
• OSTI ID: 2530760
• Journal Information: Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 10 Vol. 134; ISSN 0031-9007; ISSN PRLTAO
• Publisher: American Physical SocietyCopyright Statement
• Country of Publication: United States
• Language: English