# Stability of a tachyon braneworld

## Abstract

Within the braneworld paradigm the tachyonic scalar field has been used to generate models that attempt to solve some of the open problems that physics faces nowadays, both in cosmology and high energy physics as well. When these field configurations are produced by the interplay of higher dimensional warped gravity with some matter content, braneworld models must prove to be stable under the whole set of small fluctuations of the gravitational and matter fields background, among other consistency tests. Here we present a complete proof of the stability under scalar perturbations of tachyonic thick braneworlds with an embedded maximally symmetric 4D space-time, revealing its physical consistency. This family of models contains a recently reported tachyonic de Sitter thick braneworld which possesses a series of appealing properties. These features encompass complete regularity, asymptotic flatness (instead of being asymptotically dS or AdS) even when it contains a negative bulk cosmological constant, a relevant 3-brane with dS metric which naturally arises from the full set of field equations of the 5D background (it is not imposed), qualitatively describing the inflationary epochs of our Universe, and a graviton spectrum with a single zero mode bound state that accounts for the 4D graviton localised onmore »

- Authors:

- Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México,Apartado Postal 48-3, 62251, Cuernavaca, Morelos (Mexico)
- Instituto de Física, Benemérita Universidad Autónoma de Puebla,Apartado Postal J-48, 72570, Puebla, Puebla (Mexico)
- (Mexico)
- (UFABC),Avenida dos Estados, 5001, Santo André, SP (Brazil)
- Centro de Matemática, Computação e Cognição, Universidade Federal do ABC (UFABC),Avenida dos Estados, 5001, Santo André, SP (Brazil)

- Publication Date:

- Sponsoring Org.:
- SCOAP3, CERN, Geneva (Switzerland)

- OSTI Identifier:
- 22458431

- Resource Type:
- Journal Article

- Journal Name:
- Journal of Cosmology and Astroparticle Physics

- Additional Journal Information:
- Journal Volume: 2016; Journal Issue: 01; Other Information: PUBLISHER-ID: JCAP01(2016)047; OAI: oai:repo.scoap3.org:13624; Article funded by SCOAP3. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 License. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1475-7516

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; BOUND STATE; BRANES; COSMOLOGICAL CONSTANT; COSMOLOGICAL MODELS; COULOMB FIELD; DE SITTER SPACE; FIELD EQUATIONS; FOUR-DIMENSIONAL CALCULATIONS; GRAVITATION; KALUZA-KLEIN THEORY; MASS SPECTRA; METRICS; M-THEORY; SCALAR FIELDS; SPACE-TIME; TACHYONS; UNIVERSE; VECTOR FIELDS

### Citation Formats

```
Germán, Gabriel, Herrera-Aguilar, Alfredo, Instituto de Física y Matemáticas, Universidad Michoacana de San Nicolás de Hidalgo,Ciudad Universitaria, CP 58040, Morelia, Michoacán, Kuerten, André Martorano, Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Malagón-Morejón, Dagoberto, and Rocha, Roldão da.
```*Stability of a tachyon braneworld*. United States: N. p., 2016.
Web. doi:10.1088/1475-7516/2016/01/047.

```
Germán, Gabriel, Herrera-Aguilar, Alfredo, Instituto de Física y Matemáticas, Universidad Michoacana de San Nicolás de Hidalgo,Ciudad Universitaria, CP 58040, Morelia, Michoacán, Kuerten, André Martorano, Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Malagón-Morejón, Dagoberto, & Rocha, Roldão da.
```*Stability of a tachyon braneworld*. United States. doi:10.1088/1475-7516/2016/01/047.

```
Germán, Gabriel, Herrera-Aguilar, Alfredo, Instituto de Física y Matemáticas, Universidad Michoacana de San Nicolás de Hidalgo,Ciudad Universitaria, CP 58040, Morelia, Michoacán, Kuerten, André Martorano, Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Malagón-Morejón, Dagoberto, and Rocha, Roldão da. Tue .
"Stability of a tachyon braneworld". United States. doi:10.1088/1475-7516/2016/01/047.
```

```
@article{osti_22458431,
```

title = {Stability of a tachyon braneworld},

author = {Germán, Gabriel and Herrera-Aguilar, Alfredo and Instituto de Física y Matemáticas, Universidad Michoacana de San Nicolás de Hidalgo,Ciudad Universitaria, CP 58040, Morelia, Michoacán and Kuerten, André Martorano and Centro de Ciências Naturais e Humanas, Universidade Federal do ABC and Malagón-Morejón, Dagoberto and Rocha, Roldão da},

abstractNote = {Within the braneworld paradigm the tachyonic scalar field has been used to generate models that attempt to solve some of the open problems that physics faces nowadays, both in cosmology and high energy physics as well. When these field configurations are produced by the interplay of higher dimensional warped gravity with some matter content, braneworld models must prove to be stable under the whole set of small fluctuations of the gravitational and matter fields background, among other consistency tests. Here we present a complete proof of the stability under scalar perturbations of tachyonic thick braneworlds with an embedded maximally symmetric 4D space-time, revealing its physical consistency. This family of models contains a recently reported tachyonic de Sitter thick braneworld which possesses a series of appealing properties. These features encompass complete regularity, asymptotic flatness (instead of being asymptotically dS or AdS) even when it contains a negative bulk cosmological constant, a relevant 3-brane with dS metric which naturally arises from the full set of field equations of the 5D background (it is not imposed), qualitatively describing the inflationary epochs of our Universe, and a graviton spectrum with a single zero mode bound state that accounts for the 4D graviton localised on the brane and is separated from the continuum of Kaluza-Klein massive graviton excitations by a mass gap. The presence of this mass gap in the graviton spectrum makes the extra-dimensional corrections to Newton’s law decay exponentially. Gauge vector fields with a single massless bound state in its mass spectrum are also localised on this braneworld model a fact that allows us to recover the Coulomb’s law of our 4D world. All these properties of the above referred tachyonic braneworld together with the positive stability analysis provided in this work, constitute a firm step towards the construction of realistic cosmological models within the braneworld paradigm.},

doi = {10.1088/1475-7516/2016/01/047},

journal = {Journal of Cosmology and Astroparticle Physics},

issn = {1475-7516},

number = 01,

volume = 2016,

place = {United States},

year = {2016},

month = {1}

}