Primordial Black Holes and Induced Gravitational Waves from Inflation with History-Dependent Effective Dissipation
Abstract
We study inflation with an exponential factor multiplying the scalar Lagrangian and depending on the accumulated expansion history through a field-dependent coupling. Variation of the complete action on a finite interval yields an adjoint response with a final-time boundary condition. We derive the background and coupled scalar perturbation equations and examine five benchmarks for an exponential plateau potential and a smooth single-window coupling. The kinetic, direct-coupling and adjoint contributions nearly cancel, producing transient positive minima of the first Hubble slow-roll parameter, ε1, without a comparable reduction in field velocity. The scalar spectra, normalized to the cosmic microwave background (CMB) pivot amplitude, develop localized peaks with amplitudes $0.033−−0.098$. Under Gaussian statistics and the adopted radiation-era collapse prescription, the the primordial black hole (PBH) abundance peaks span masses from 4.52×10−13 to 34.05 M⊙. The lightest-mass benchmark reaches fPBH≃0.99, allowing nearly all dark matter within the monochromatic approximation. The accompanying scalar-induced gravitational-wave spectra span peak frequencies from 6.78×10−10 to 5.92×10−3 Hz, with selected benchmarks lying within the projected sensitivities of future detectors.
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BibTeX
@misc{rashidi2026primordial,
title = {{Primordial Black Holes and Induced Gravitational Waves from Inflation with History-Dependent Effective Dissipation}},
author = {Narges Rashidi},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2611.06329},
eprint = {2611.06329},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2611.06329},
}
RIS
TY - UNPB
TI - Primordial Black Holes and Induced Gravitational Waves from Inflation with History-Dependent Effective Dissipation
AU - Narges Rashidi
PY - 2026
DA - 2026/11/04
PB - arXiv
DO - 10.48550/arxiv.2611.06329
UR - https://arxiv.org/abs/2611.06329
AB - We study inflation with an exponential factor multiplying the scalar Lagrangian and depending on the accumulated expansion history through a field-dependent coupling. Variation of the complete action on a finite interval yields an adjoint response with a final-time boundary condition. We derive the background and coupled scalar perturbation equations and examine five benchmarks for an exponential plateau potential and a smooth single-window coupling. The kinetic, direct-coupling and adjoint contributions nearly cancel, producing transient positive minima of the first Hubble slow-roll parameter, ε_1, without a comparable reduction in field velocity. The scalar spectra, normalized to the cosmic microwave background (CMB) pivot amplitude, develop localized peaks with amplitudes $0.033−−0.098$. Under Gaussian statistics and the adopted radiation-era collapse prescription, the the primordial black hole (PBH) abundance peaks span masses from 4.52×10^−13 to 34.05 M_⊙. The lightest-mass benchmark reaches f_PBH≃0.99, allowing nearly all dark matter within the monochromatic approximation. The accompanying scalar-induced gravitational-wave spectra span peak frequencies from 6.78×10^−10 to 5.92×10^−3 Hz, with selected benchmarks lying within the projected sensitivities of future detectors.
ER -