Expanding universe with nonlinear gravitational waves

Taishi Ikeda, Chul Moon Yoo, Yasusada Nambu

研究成果: ジャーナルへの寄稿学術誌査読

5 被引用数 (Scopus)


We test the validity of Isaacson's formula which states that high frequency and low amplitude gravitational waves behave as a radiation fluid on average. For this purpose, we numerically construct a solution of the vacuum Einstein equations which contains nonlinear standing gravitational waves. The solution is constructed in a cubic box with periodic boundary conditions. The time evolution is solved in a gauge in which the trace of the extrinsic curvature K of the time slice becomes spatially uniform. Then, the Hubble expansion rate H is defined by H=-K/3 and compared with the effective scale factor L defined by the proper volume, area and length of the cubic box. We find that, even when the wave length of the gravitational waves is comparable to the Hubble scale, the deviation from Isaacson's formula H-L-2 is at most 3% without taking a temporal average and is below 0.1% with a temporal average.

ジャーナルPhysical Review D - Particles, Fields, Gravitation and Cosmology
出版ステータス出版済み - 8月 21 2015

!!!All Science Journal Classification (ASJC) codes

  • 核物理学および高エネルギー物理学
  • 物理学および天文学(その他)


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