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arXiv · 1502.03881

Scale-invariant scalar spectrum from the nonminimal derivative coupling with fourth-order term

Yun Soo Myung·Taeyoon Moon
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Abstract

An exactly scale-invariant spectrum of scalar perturbation generated during de Sitter spacetime is found from the gravity model of the nonminimal derivative coupling with fourth-order term. The nonminimal derivative coupling term generates a healthy (ghost-free) fourth-order derivative term, while the fourth-order term provides an unhealthy (ghost) fourth-order derivative term. The Harrison-Zel'dovich spectrum obtained from Fourier transforming the fourth-order propagator in de Sitter space is recovered by computing the power spectrum in its momentum space directly. It shows that this model provides a truly scale-invariant spectrum, in addition to the Lee-Wick scalar theory.

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Yun Soo Myung, Taeyoon Moon. 2015-07-22. Scale-invariant scalar spectrum from the nonminimal derivative coupling with fourth-order term. https://doi.org/10.1142/s0218271815500959

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