# Scalar-torsion mode in a cosmological model of the Poincaré gauge theory of gravity

## Abstract

We investigate the scalar-torsion mode in a cosmological model of the Poincaré gauge theory of gravity. We treat the geometric effect of torsion as an effective quantity, which behaves like dark energy, and study the effective equation of state (EoS) of the model. We concentrate on two cases with the constant curvature solution and positive kinetic energy, respectively. In the former, we find that the torsion EoS has different values in the various stages of the universe. In particular, it behaves like the radiation (matter) EoS of w{sub r} = 1/3 (w{sub m} = 0) in the radiation (matter) dominant epoch, while in the late time the torsion density is supportive for the accelerating universe. In the latter, our numerical analysis shows that in general the EoS has an asymptotic behavior in the high redshift regime, while it could cross the phantom divide line in the low redshift regime.

- Authors:

- Department of Physics, National Tsing Hua University, Hsinchu, 300 Taiwan (China)

- Publication Date:

- OSTI Identifier:
- 22279682

- Resource Type:
- Journal Article

- Journal Name:
- Journal of Cosmology and Astroparticle Physics

- Additional Journal Information:
- Journal Volume: 2012; Journal Issue: 11; 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; ASTROPHYSICS; ASYMPTOTIC SOLUTIONS; COSMOLOGICAL MODELS; COSMOLOGY; EQUATIONS OF STATE; GAUGE INVARIANCE; GRAVITATION; KINETIC ENERGY; NONLUMINOUS MATTER; NUMERICAL ANALYSIS; PHANTOMS; RED SHIFT; SCALARS; TORSION; UNIVERSE

### Citation Formats

```
Tseng, Huan-Hsin, Lee, Chung-Chi, and Geng, Chao-Qiang, E-mail: d943335@oz.nthu.edu.tw, E-mail: g9522545@oz.nthu.edu.tw, E-mail: geng@phys.nthu.edu.tw.
```*Scalar-torsion mode in a cosmological model of the Poincaré gauge theory of gravity*. United States: N. p., 2012.
Web. doi:10.1088/1475-7516/2012/11/013.

```
Tseng, Huan-Hsin, Lee, Chung-Chi, & Geng, Chao-Qiang, E-mail: d943335@oz.nthu.edu.tw, E-mail: g9522545@oz.nthu.edu.tw, E-mail: geng@phys.nthu.edu.tw.
```*Scalar-torsion mode in a cosmological model of the Poincaré gauge theory of gravity*. United States. doi:10.1088/1475-7516/2012/11/013.

```
Tseng, Huan-Hsin, Lee, Chung-Chi, and Geng, Chao-Qiang, E-mail: d943335@oz.nthu.edu.tw, E-mail: g9522545@oz.nthu.edu.tw, E-mail: geng@phys.nthu.edu.tw. Thu .
"Scalar-torsion mode in a cosmological model of the Poincaré gauge theory of gravity". United States. doi:10.1088/1475-7516/2012/11/013.
```

```
@article{osti_22279682,
```

title = {Scalar-torsion mode in a cosmological model of the Poincaré gauge theory of gravity},

author = {Tseng, Huan-Hsin and Lee, Chung-Chi and Geng, Chao-Qiang, E-mail: d943335@oz.nthu.edu.tw, E-mail: g9522545@oz.nthu.edu.tw, E-mail: geng@phys.nthu.edu.tw},

abstractNote = {We investigate the scalar-torsion mode in a cosmological model of the Poincaré gauge theory of gravity. We treat the geometric effect of torsion as an effective quantity, which behaves like dark energy, and study the effective equation of state (EoS) of the model. We concentrate on two cases with the constant curvature solution and positive kinetic energy, respectively. In the former, we find that the torsion EoS has different values in the various stages of the universe. In particular, it behaves like the radiation (matter) EoS of w{sub r} = 1/3 (w{sub m} = 0) in the radiation (matter) dominant epoch, while in the late time the torsion density is supportive for the accelerating universe. In the latter, our numerical analysis shows that in general the EoS has an asymptotic behavior in the high redshift regime, while it could cross the phantom divide line in the low redshift regime.},

doi = {10.1088/1475-7516/2012/11/013},

journal = {Journal of Cosmology and Astroparticle Physics},

issn = {1475-7516},

number = 11,

volume = 2012,

place = {United States},

year = {2012},

month = {11}

}