Re: confused w/ decoherence

mahdiarnt schrieb:
Thanks very much for all those illuminating points. There are two more
questions:

1) So you say that in the "frictionless case," (4) is correct for a
pure state. Then it means that the results of successive experiments
are independent of the previous ones (or am I wrong?) Then there is no
wave function reduction at this level at all, whatever interpretation
we choose. This is weird (and perhaps measurable),

No. Measurement always requires irreversibility and hence dissipation
(what Parrott calles friction). Otherwise there is no macroscopic
record available. (Macroscopic observables are always described by
thermodynamics, which is intrinsically dissipative, due to the
second law.

The book
V.B. Braginsky and F.Ya. Khalili,
Quantum measurement,
Cambridge Univ. Press, Cambridge 1992
gives a good description of modern measurement theory.

Arnold Neumaier

.

Relevant Pages

  • Re: confused w/ decoherence
    ... particles each of which are observers themselves. ... See 'Quantum Noise: A ... measurement still remains weird. ... to abandon the entire concept of measurement in the "frictionless" ...
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  • Re: confused w/ decoherence
    ... wave function reduction at this level at all, ... to abandon the entire concept of measurement in the "frictionless" ... resembles what we would expect from wave function collapse? ...
    (sci.physics.research)