### Abstract

We investigate photon emission from a moving particle in an expanding universe. This process is analogous to the radiation from an accelerated charge in the classical electromagnetic theory. Using the framework of quantum field theory in curved spacetime, we demonstrate that the Wentzel-Kramers-Brillouin (WKB) approximation leads to the Larmor formula for the rate of the radiation of energy from a moving charge in an expanding universe. Using exactly solvable models in a radiation-dominated universe and in a Milne universe, we examine the validity of the WKB formula. It is shown that the quantum effect suppresses the radiation energy in comparison with the WKB formula.

Original language | English |
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Article number | 013 |

Journal | Journal of Cosmology and Astroparticle Physics |

Issue number | 11 |

DOIs | |

Publication status | Published - Nov 1 2006 |

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### All Science Journal Classification (ASJC) codes

- Astronomy and Astrophysics

### Cite this

*Journal of Cosmology and Astroparticle Physics*, (11), [013]. https://doi.org/10.1088/1475-7516/2006/11/013

**Classical and quantum radiation from a moving charge in an expanding universe.** / Nomura, Hidenori; Sasaki, Misao; Yamamoto, Kazuhiro.

Research output: Contribution to journal › Review article

*Journal of Cosmology and Astroparticle Physics*, no. 11, 013. https://doi.org/10.1088/1475-7516/2006/11/013

}

TY - JOUR

T1 - Classical and quantum radiation from a moving charge in an expanding universe

AU - Nomura, Hidenori

AU - Sasaki, Misao

AU - Yamamoto, Kazuhiro

PY - 2006/11/1

Y1 - 2006/11/1

N2 - We investigate photon emission from a moving particle in an expanding universe. This process is analogous to the radiation from an accelerated charge in the classical electromagnetic theory. Using the framework of quantum field theory in curved spacetime, we demonstrate that the Wentzel-Kramers-Brillouin (WKB) approximation leads to the Larmor formula for the rate of the radiation of energy from a moving charge in an expanding universe. Using exactly solvable models in a radiation-dominated universe and in a Milne universe, we examine the validity of the WKB formula. It is shown that the quantum effect suppresses the radiation energy in comparison with the WKB formula.

AB - We investigate photon emission from a moving particle in an expanding universe. This process is analogous to the radiation from an accelerated charge in the classical electromagnetic theory. Using the framework of quantum field theory in curved spacetime, we demonstrate that the Wentzel-Kramers-Brillouin (WKB) approximation leads to the Larmor formula for the rate of the radiation of energy from a moving charge in an expanding universe. Using exactly solvable models in a radiation-dominated universe and in a Milne universe, we examine the validity of the WKB formula. It is shown that the quantum effect suppresses the radiation energy in comparison with the WKB formula.

UR - http://www.scopus.com/inward/record.url?scp=42749109058&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=42749109058&partnerID=8YFLogxK

U2 - 10.1088/1475-7516/2006/11/013

DO - 10.1088/1475-7516/2006/11/013

M3 - Review article

AN - SCOPUS:42749109058

JO - Journal of Cosmology and Astroparticle Physics

JF - Journal of Cosmology and Astroparticle Physics

SN - 1475-7516

IS - 11

M1 - 013

ER -