English

Constant-roll inflation with non-minimally derivative coupling

General Relativity and Quantum Cosmology 2024-07-22 v2

Abstract

We investigate the constant-roll inflation with non-minimally kinetic coupling to the Einstein tensor. With the slow-roll parameter ηϕ=ϕ¨/(Hϕ˙)\eta_\phi = -\ddot{\phi}/(H\dot{\phi}) being a constant, we calculate the power spectra for scalar and tensor perturbations, and derive the expressions for the scalar spectral tilt nsn_s, the tensor spectral tilt nTn_T, and the tensor-to-scalar ratio rr. We find that the expressions for nsn_s are different with different ordering of taking the derivative of the scalar power spectrum with respect to the scale kk and the horizon crossing condition csk=aHc_sk=aH in the constant-roll inflation, the consistency relation r=8nTr=-8n_T does not hold if ηϕ|\eta_\phi| is not small, and the duality of the tensor-to-scalar ratio between the slow-roll inflation and ultra-slow-roll inflation does not exist in inflationary models with non-minimally derivative coupling. The result offers a fresh perspective on the understanding of the inflationary models with non-minimally derivative coupling and is helpful for the production of scalar induced gravitational waves in the framework of ultra-slow-roll inflation with non-minimally derivative coupling.

Keywords

Cite

@article{arxiv.2404.04978,
  title  = {Constant-roll inflation with non-minimally derivative coupling},
  author = {Jie Liu and Yungui Gong and Zhu Yi},
  journal= {arXiv preprint arXiv:2404.04978},
  year   = {2024}
}

Comments

8 pages, accepted by Communications in Theoretical Physics

R2 v1 2026-06-28T15:46:36.966Z