# Correspondence between loop-inspired and braneworld cosmology

## Abstract

Braneworld scenarios are motivated by string/M-theory and can be characterized by the way in which they modify the conventional Friedmann equations of Einstein gravity. An alternative approach to quantum gravity, however, is the loop quantum cosmology program. In the semiclassical limit, the cosmic dynamics in this scenario can also be described by a set of modified Friedmann equations. We demonstrate that a dynamical correspondence can be established between these two paradigms at the level of the effective field equations. This allows qualitatively similar features between the two approaches to be compared and contrasted as well as providing a framework for viewing braneworld scenarios in terms of constrained Hamiltonian systems. As concrete examples of this correspondence, we illustrate the relationships between different cosmological backgrounds representing scaling solutions.

- Authors:

- School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD (United Kingdom)
- Astronomy Unit, School of Mathematical Sciences, Queen Mary, University of London, Mile End Road, London, E1 4NS (United Kingdom)
- Department of Physics, Waseda University, Okubo 3-4-1, Shinjuku, Tokyo 169-8555 (Japan)

- Publication Date:

- OSTI Identifier:
- 20776720

- Resource Type:
- Journal Article

- Resource Relation:
- Journal Name: Physical Review. D, Particles Fields; Journal Volume: 73; Journal Issue: 4; Other Information: DOI: 10.1103/PhysRevD.73.043503; (c) 2006 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; COSMOLOGY; FIELD EQUATIONS; GRAVITATION; HAMILTONIANS; MATHEMATICAL SOLUTIONS; QUANTUM GRAVITY; SEMICLASSICAL APPROXIMATION; STRING MODELS

### Citation Formats

```
Copeland, Edmund J., Lidsey, James E., and Mizuno, Shuntaro.
```*Correspondence between loop-inspired and braneworld cosmology*. United States: N. p., 2006.
Web. doi:10.1103/PhysRevD.73.043503.

```
Copeland, Edmund J., Lidsey, James E., & Mizuno, Shuntaro.
```*Correspondence between loop-inspired and braneworld cosmology*. United States. doi:10.1103/PhysRevD.73.043503.

```
Copeland, Edmund J., Lidsey, James E., and Mizuno, Shuntaro. Wed .
"Correspondence between loop-inspired and braneworld cosmology". United States.
doi:10.1103/PhysRevD.73.043503.
```

```
@article{osti_20776720,
```

title = {Correspondence between loop-inspired and braneworld cosmology},

author = {Copeland, Edmund J. and Lidsey, James E. and Mizuno, Shuntaro},

abstractNote = {Braneworld scenarios are motivated by string/M-theory and can be characterized by the way in which they modify the conventional Friedmann equations of Einstein gravity. An alternative approach to quantum gravity, however, is the loop quantum cosmology program. In the semiclassical limit, the cosmic dynamics in this scenario can also be described by a set of modified Friedmann equations. We demonstrate that a dynamical correspondence can be established between these two paradigms at the level of the effective field equations. This allows qualitatively similar features between the two approaches to be compared and contrasted as well as providing a framework for viewing braneworld scenarios in terms of constrained Hamiltonian systems. As concrete examples of this correspondence, we illustrate the relationships between different cosmological backgrounds representing scaling solutions.},

doi = {10.1103/PhysRevD.73.043503},

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

number = 4,

volume = 73,

place = {United States},

year = {Wed Feb 15 00:00:00 EST 2006},

month = {Wed Feb 15 00:00:00 EST 2006}

}