  Developing an earlier proposal (Ne'eman, Damnjanovic, etc), we show herein
that there is a Landau continuous phase transition from the exact quantum
dynamics to the effectively classical one, occurring via spontaneous
superposition breaking (effective hiding), as a special case of the
corresponding general formalism (Bernstein). Critical values of the order
parameters for this transition are determined by Heisenberg's indeterminacy
relations, change continuously, and are in excellent agreement with the recent
and remarkable experiments with Bose condensation. It is also shown that such a
phase transition can sucessfully model self-collapse (self-decoherence), as an
effective classical phenomenon, on the measurement device. This then induces a
relative collapse (relative decoherence) as an effective quantum phenomenon on
the measured quantum object by measurement.
  We demonstrate this (including the case of Bose-Einstein condensation) in the
well-known cases of the Stern-Gerlach spin measurement, Bell's inequality and
the recently discussed quantum superposition on a mirror a la Marshall et al.
These results provide for a proof that quantum mechanics, in distinction to all
absolute collapse and hidden-variable theories, is local and objective. There
now appear no insuperable obstacles to solving the open problems in quantum
theory of measurement and foundation of quantum mechanics, and strictly within
the standard quantum-mechanical formalism. Simply put, quantum mechanics is a
field theory over the Hilbert space, the classical mechanics characteristics of
which emerge through spontaneous superposition breaking.
