Emergence of classicality for primordial fluctuations: Concepts and analogies

May, 1998
24 pages
Published in:
  • Annalen Phys. 7 (1998) 137-158
e-Print:
Report number:
  • FREIBURG-THEP-98-7,
  • FREIBURG-THP-98-7

Citations per year

1998200520122019202502468
Abstract: (arXiv)
We clarify the way in which cosmological perturbations of quantum origin, produced during inflation, assume classical properties. Two features play an important role in this process: First, the dynamics of fluctuations which are presently on large cosmological scales leads to a very peculiar state (highly squeezed) that is indistinguishable, in a precise sense, from a classical stochastic process. This holds for almost all initial quantum states. Second, the process of decoherence by interaction with the environment distinguishes the field amplitude basis as a robust pointer basis. We discuss in detail the interplay between these features and use simple analogies such as the free quantum particle to illustrate the main conceptual issues.
Note:
  • 25 pages, Latex, typos corrected, reference added
  • inflation
  • density: perturbation
  • spectrum: fluctuation
  • model: stochastic
  • classical
  • decoherence
  • quantum mechanics
  • squeezed state