State reduction and cosmic anisotropy
Abstract
Between the quantum domain and the classical world of facts there is an intermediate domain for which a ``classical'' probabilistic description is appropriate. As a result of decoherence, such a description obeys the classical additivity of probabilities. In contrast to the usual interpretation in classical probability theory, however, the ``classical'' probability which emerges from an underlying quantum theory is meant to be applicable to a single system, such as the universe.
It is argued that small inhomogeneities and anisotropies in the very early universe should be described probabilistically. If, furthermore, the transition between this probabilistic description and a later deterministic description happens as late as after the decoupling of photons, then the smoothness of the microwave background receives a different interpretation: it is not because the fluctuations at decoupling were extremely small, but because the contributions from different fluctuations add to smooth things out.
 Publication:

After the first three minutes
 Pub Date:
 April 1991
 DOI:
 10.1063/1.40442
 Bibcode:
 1991AIPC..222..155W
 Keywords:

 Anisotropy;
 Big Bang Cosmology;
 Evolution (Development);
 Relic Radiation;
 Universe;
 Astronomical Models;
 Density Distribution;
 Microwaves;
 Probability Theory;
 Astrophysics;
 98.80.Dr;
 98.70.Vc;
 98.80.Bp;
 Background radiations;
 Origin and formation of the Universe