Entanglement of Primordial Fluctuations(Quantum Realm-Nonlocal Correlation and Uncertainty-)

Abstract

Inflation provides a mechanism of generation of primordial inhomogeneity which is needed for the formation of large-scale structures in our present universe. After the wavelength of generated quantum fluctuations becomes larger than the Hubble horizon, the quantum nature of the fluctuation is expected to be lost and the statistical property of fluctuations is represented by the classical distribution function. This assumption of "quantum to classical transition of primordial fluctuations" must be justified. In this article, we introduce the approach to apprehend the mechanism of quantum to classical transition of primordial fluctuations from the view point of the quantum entanglement.