Second-Order Gauge-Invariant Cosmological Perturbation Theory: Current Status

  title={Second-Order Gauge-Invariant Cosmological Perturbation Theory: Current Status},
  author={Kouji Nakamura},
  journal={Advances in Astronomy},
The current status of the recent developments of the second-order gauge-invariant cosmological perturbation theory is reviewed. To show the essence of this perturbation theory, we concentrate only on the universe filled with a single scalar field. Through this paper, we point out the problems which should be clarified for the further theoretical sophistication of this perturbation theory. We also expect that this theoretical sophistication will be also useful to discuss the theoretical… 

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