Classical and quantum correlations of scalar field in the inflationary universe

Yasusada Nambu, Yuji Ohsumi

Research output: Contribution to journalArticlepeer-review

39 Citations (Scopus)


We investigate classical and quantum correlations of a quantum field in the inflationary universe using a particle detector model. By considering the entanglement and correlations between two comoving detectors interacting with a scalar field, we find that the entanglement between the detectors becomes zero after their physical separation exceeds the Hubble horizon. Furthermore, the quantum discord, which is defined as the quantum part of total correlation, approaches zero on the super horizon scale. These behaviors support the appearance of the classical nature of the quantum fluctuation generated during the inflationary era.

Original languageEnglish
Article number044028
JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
Issue number4
Publication statusPublished - Aug 8 2011
Externally publishedYes

All Science Journal Classification (ASJC) codes

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


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