# Coupled bulk and brane fields about a de Sitter brane

## Abstract

We consider the evolution of a bulk scalar field in anti-de Sitter (AdS) spacetime linearly coupled to a scalar field on a de Sitter boundary brane. We present results of a spectral analysis of the system, and find that the model can exhibit both bound and continuum resonant modes. We find that zero, one, or two bound states may exist, depending upon the masses of the brane and bulk fields relative to the Hubble length and the AdS curvature scale and the coupling strength. In all cases, we find a critical coupling above which there exists a tachyonic bound state. We show how the 5-dimensional spectral results can be interpreted in terms of a 4-dimensional effective theory for the bound states. We find excellent agreement between our analytic results and the results of a new numerical code developed to model the evolution of bulk fields coupled to degrees of freedom on a moving brane. This code can be used to model the behavior of brane-world cosmological perturbations in scenarios for which no analytic results are known.

- Authors:

- Institute of Cosmology and Gravitation, University of Portsmouth, Portsmouth PO1 2EG (United Kingdom)

- Publication Date:

- OSTI Identifier:
- 21020371

- Resource Type:
- Journal Article

- Resource Relation:
- Journal Name: Physical Review. D, Particles Fields; Journal Volume: 75; Journal Issue: 8; Other Information: DOI: 10.1103/PhysRevD.75.084002; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; BOUND STATE; BRANES; COUPLING; DE SITTER GROUP; DEGREES OF FREEDOM; DISTURBANCES; MANY-DIMENSIONAL CALCULATIONS; MASS; QUANTUM FIELD THEORY; SCALAR FIELDS; SPACE-TIME; TACHYONS

### Citation Formats

```
Cardoso, Antonio, Koyama, Kazuya, Mennim, Andrew, Seahra, Sanjeev S., and Wands, David.
```*Coupled bulk and brane fields about a de Sitter brane*. United States: N. p., 2007.
Web. doi:10.1103/PHYSREVD.75.084002.

```
Cardoso, Antonio, Koyama, Kazuya, Mennim, Andrew, Seahra, Sanjeev S., & Wands, David.
```*Coupled bulk and brane fields about a de Sitter brane*. United States. doi:10.1103/PHYSREVD.75.084002.

```
Cardoso, Antonio, Koyama, Kazuya, Mennim, Andrew, Seahra, Sanjeev S., and Wands, David. Sun .
"Coupled bulk and brane fields about a de Sitter brane". United States.
doi:10.1103/PHYSREVD.75.084002.
```

```
@article{osti_21020371,
```

title = {Coupled bulk and brane fields about a de Sitter brane},

author = {Cardoso, Antonio and Koyama, Kazuya and Mennim, Andrew and Seahra, Sanjeev S. and Wands, David},

abstractNote = {We consider the evolution of a bulk scalar field in anti-de Sitter (AdS) spacetime linearly coupled to a scalar field on a de Sitter boundary brane. We present results of a spectral analysis of the system, and find that the model can exhibit both bound and continuum resonant modes. We find that zero, one, or two bound states may exist, depending upon the masses of the brane and bulk fields relative to the Hubble length and the AdS curvature scale and the coupling strength. In all cases, we find a critical coupling above which there exists a tachyonic bound state. We show how the 5-dimensional spectral results can be interpreted in terms of a 4-dimensional effective theory for the bound states. We find excellent agreement between our analytic results and the results of a new numerical code developed to model the evolution of bulk fields coupled to degrees of freedom on a moving brane. This code can be used to model the behavior of brane-world cosmological perturbations in scenarios for which no analytic results are known.},

doi = {10.1103/PHYSREVD.75.084002},

journal = {Physical Review. D, Particles Fields},

number = 8,

volume = 75,

place = {United States},

year = {Sun Apr 15 00:00:00 EDT 2007},

month = {Sun Apr 15 00:00:00 EDT 2007}

}