Separate universe and the back reaction of long wavelength fluctuations

Yasusada Nambu

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


We investigate the back reaction of cosmological long wavelength perturbations on the evolution of the Universe. By applying the renormalization group method to a Friedmann-Robertson-Walker universe with long wavelength fluctuations, we demonstrate that the renormalized solution with the back reaction effect is equivalent to that of the separate universe. Then, using the effective Friedmann equation, we show that only the nonadiabatic mode of long wavelength fluctuations affects the expansion law of the spatially averaged universe.

Original languageEnglish
Article number084016
Pages (from-to)1-5
Number of pages5
JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
Issue number8
Publication statusPublished - Apr 15 2005
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Nuclear and High Energy Physics
  • Physics and Astronomy (miscellaneous)


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