#### Document Type

Article

#### Date

5-1-2008

#### Language

English

#### Disciplines

Physics

#### Description/Abstract

We apply the effective field theory approach to the coupled metric-inflaton system, in order to investigate the impact of higher dimension operators on the spectrum of scalar and tensor perturbations in the short-wavelength regime. In both cases, effective corrections at tree-level become important when the Hubble parameter is of the order of the Planck mass, or when the physical wave number of a cosmological perturbation mode approaches the square of the Planck mass divided by the Hubble constant. Thus, the cut-off length below which conventional cosmological perturbation theory does not apply is likely to be much smaller than the Planck length. This has implications for the observability of "trans-Planckian" effects in the spectrum of primordial perturbations.

#### Repository Citation

Armendariz-Picon, Christian; Fontanini, Michele; Penco, Riccardo; and Trodden, Mark, "Where does Cosmological Perturbation Theory Break Down?" (2008). *Physics*. 213.

https://surface.syr.edu/phy/213

#### Source

Harvested from Arxiv.org

## Additional Information

25 pages, uses FeynMP More information at http://arxiv.org/abs/0805.0114