# On adiabatic invariant in generalized Galileon theories

## Abstract

We consider background dynamics of generalized Galileon theories in the context of inflation, where gravity and inflaton are non-minimally coupled to each other. In the inflaton oscillation regime, the Hubble parameter and energy density oscillate violently in many cases, in contrast to the Einstein gravity with minimally coupled inflaton. However, we find that there is an adiabatic invariant in the inflaton oscillation regime in any generalized Galileon theory. This adiabatic invariant is useful in estimating the expansion law of the universe and also the particle production rate due to the oscillation of the Hubble parameter.

- Authors:

- Department of Physics, Faculty of Science, The University of Tokyo, Bunkyo-ku, Tokyo 133-0033 (Japan)
- Kavli IPMU (WPI), UTIAS, The University of Tokyo, Kashiwa, Chiba 277-8583 (Japan)

- Publication Date:

- OSTI Identifier:
- 22525228

- 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; ENERGY DENSITY; GRAVITATION; INFLATIONARY UNIVERSE; INFLATONS; OSCILLATIONS; PARTICLE PRODUCTION; UNIVERSE

### Citation Formats

```
Ema, Yohei, Jinno, Ryusuke, Nakayama, Kazunori, and Mukaida, Kyohei, E-mail: ema@hep-th.phys.s.u-tokyo.ac.jp, E-mail: jinno@hep-th.phys.s.u-tokyo.ac.jp, E-mail: kyohei.mukaida@ipmu.jp, E-mail: kazunori@hep-th.phys.s.u-tokyo.ac.jp.
```*On adiabatic invariant in generalized Galileon theories*. United States: N. p., 2015.
Web. doi:10.1088/1475-7516/2015/10/049.

```
Ema, Yohei, Jinno, Ryusuke, Nakayama, Kazunori, & Mukaida, Kyohei, E-mail: ema@hep-th.phys.s.u-tokyo.ac.jp, E-mail: jinno@hep-th.phys.s.u-tokyo.ac.jp, E-mail: kyohei.mukaida@ipmu.jp, E-mail: kazunori@hep-th.phys.s.u-tokyo.ac.jp.
```*On adiabatic invariant in generalized Galileon theories*. United States. doi:10.1088/1475-7516/2015/10/049.

```
Ema, Yohei, Jinno, Ryusuke, Nakayama, Kazunori, and Mukaida, Kyohei, E-mail: ema@hep-th.phys.s.u-tokyo.ac.jp, E-mail: jinno@hep-th.phys.s.u-tokyo.ac.jp, E-mail: kyohei.mukaida@ipmu.jp, E-mail: kazunori@hep-th.phys.s.u-tokyo.ac.jp. Thu .
"On adiabatic invariant in generalized Galileon theories". United States. doi:10.1088/1475-7516/2015/10/049.
```

```
@article{osti_22525228,
```

title = {On adiabatic invariant in generalized Galileon theories},

author = {Ema, Yohei and Jinno, Ryusuke and Nakayama, Kazunori and Mukaida, Kyohei, E-mail: ema@hep-th.phys.s.u-tokyo.ac.jp, E-mail: jinno@hep-th.phys.s.u-tokyo.ac.jp, E-mail: kyohei.mukaida@ipmu.jp, E-mail: kazunori@hep-th.phys.s.u-tokyo.ac.jp},

abstractNote = {We consider background dynamics of generalized Galileon theories in the context of inflation, where gravity and inflaton are non-minimally coupled to each other. In the inflaton oscillation regime, the Hubble parameter and energy density oscillate violently in many cases, in contrast to the Einstein gravity with minimally coupled inflaton. However, we find that there is an adiabatic invariant in the inflaton oscillation regime in any generalized Galileon theory. This adiabatic invariant is useful in estimating the expansion law of the universe and also the particle production rate due to the oscillation of the Hubble parameter.},

doi = {10.1088/1475-7516/2015/10/049},

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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