# Breaking of spatial diffeomorphism invariance, inflation and the spectrum of cosmological perturbations

## Abstract

Standard inflationary models yield a characteristic signature of a primordial power spectrum with a red tensor and scalar tilt. Nevertheless, Cannone et al. [1] recently suggested that, by breaking the assumption of spatial diffeomorphism invariance in the context of the effective field theory of inflation, a blue tensor spectrum can be achieved without violating the Null Energy Condition. In this context, we explore in which cases the inflationary model of [2] can yield a blue tilt of the tensor modes along with a red tilt in the scalar spectrum. Ultimately, we analyze under which conditions the model of [3] can reproduce the specific consistency relation of String Gas Cosmology.

- Authors:

- Department of Physics, McGill University, 3600 rue University, Montréal, QC, H3A 2T8 (Canada)

- Publication Date:

- OSTI Identifier:
- 22525293

- Resource Type:
- Journal Article

- Journal Name:
- Journal of Cosmology and Astroparticle Physics

- Additional Journal Information:
- Journal Volume: 2015; Journal Issue: 10; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1475-7516

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; COSMOLOGICAL INFLATION; COSMOLOGY; DISTURBANCES; ENERGY SPECTRA; FIELD THEORIES; INFLATIONARY UNIVERSE; SCALARS; TENSORS

### Citation Formats

```
Graef, L.L., and Brandenberger, R., E-mail: leilagraef@usp.br, E-mail: rhb@physics.mcgill.ca.
```*Breaking of spatial diffeomorphism invariance, inflation and the spectrum of cosmological perturbations*. United States: N. p., 2015.
Web. doi:10.1088/1475-7516/2015/10/009.

```
Graef, L.L., & Brandenberger, R., E-mail: leilagraef@usp.br, E-mail: rhb@physics.mcgill.ca.
```*Breaking of spatial diffeomorphism invariance, inflation and the spectrum of cosmological perturbations*. United States. doi:10.1088/1475-7516/2015/10/009.

```
Graef, L.L., and Brandenberger, R., E-mail: leilagraef@usp.br, E-mail: rhb@physics.mcgill.ca. Thu .
"Breaking of spatial diffeomorphism invariance, inflation and the spectrum of cosmological perturbations". United States. doi:10.1088/1475-7516/2015/10/009.
```

```
@article{osti_22525293,
```

title = {Breaking of spatial diffeomorphism invariance, inflation and the spectrum of cosmological perturbations},

author = {Graef, L.L. and Brandenberger, R., E-mail: leilagraef@usp.br, E-mail: rhb@physics.mcgill.ca},

abstractNote = {Standard inflationary models yield a characteristic signature of a primordial power spectrum with a red tensor and scalar tilt. Nevertheless, Cannone et al. [1] recently suggested that, by breaking the assumption of spatial diffeomorphism invariance in the context of the effective field theory of inflation, a blue tensor spectrum can be achieved without violating the Null Energy Condition. In this context, we explore in which cases the inflationary model of [2] can yield a blue tilt of the tensor modes along with a red tilt in the scalar spectrum. Ultimately, we analyze under which conditions the model of [3] can reproduce the specific consistency relation of String Gas Cosmology.},

doi = {10.1088/1475-7516/2015/10/009},

journal = {Journal of Cosmology and Astroparticle Physics},

issn = {1475-7516},

number = 10,

volume = 2015,

place = {United States},

year = {2015},

month = {10}

}

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