PIRSA:14090082 Scientific Series Cosmology

DOI10.48660/14090082

Series: Cosmology and Gravitation

Singh, S. (2014). Evolution of quantum field, particle content, and classicality in the three stage universe. Perimeter Institute. https://pirsa.org/14090082

Singh, Suprit. Evolution of quantum field, particle content, and classicality in the three stage universe. Perimeter Institute, Sep. 18, 2014, https://pirsa.org/14090082 

@misc{ pirsa_PIRSA:14090082,
  doi = {10.48660/14090082},
  url = {https://pirsa.org/14090082},
  author = {Singh, Suprit},
  keywords = {Cosmology},
  language = {en},
  title = {Evolution of quantum field, particle content, and classicality in the three stage universe},
  publisher = {Perimeter Institute},
  year = {2014},
  month = {sep},
  note = {PIRSA:14090082 see, \url{https://pirsa.org}}
}

Abstract

I will discuss the evolution of a quantum scalar field in a toy universe which has three stages of evolution, viz., (i) an early (inflationary) de Sitter phase (ii) radiation-dominated phase and (iii) late-time (cosmological constant dominated) de Sitter phase. Using the Schr\"odinger picture, the scalar field equations are solved separately for the three stages and matched at the transition points. The boundary conditions are chosen so that field modes in the early de Sitter phase evolve from the Bunch-Davies vacuum state. I shall look the (time-dependent) particle content of this quantum state for the entire evolution of the universe and describe the various features both numerically and analytically. I shall also describe the quantum to classical transition in terms of a classicality parameter which tracks the particle creation and its effect on phase space correlation of the quantum field.

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