On Wed, Nov 04, 2015 at 10:55:56AM +1100, Bruce Kellett wrote: > On 4/11/2015 4:49 am, Brent Meeker wrote: > >I think that would have been better expressed if you had noted > >that the robust basis is not necessarily the position basis. As > >Schlosshauer notes, for atomic size things it is often the energy > >eigenvalues that are robust. But we didn't predict that; we have > >discovered it empirically. > > This is the mistake made by both Zurek and Schlosshauer: Position > and energy are variables, not bases, and for both you have the same > basis problem (both are operators in infinite dimensional Hilbert > spaces, but *different* spaces). The question as to whether a
Not different spaces - unless you're talking about completely different experiments. The basis problem is that position and energy do not commute, so along which basis has reality decohered to? Why does it seem to depend on what we're interested in measuring? > measurement is primarily one of position or of energy is depends on > the system under study and the experimental set up. But the basis in > either position or energy space still has to be chosen. Einselection > then turns out to be rather trivial because all the measurements and > interaction Hamiltonians are always expressed in terms of the > classical counterparts of the relevant variables. > > > >So would it be a complete solution of the measurement problem if > >we could predict which basis choice would provide robust > >eigenvalues? Would this prediction start from a very complex > >instrument/environment interaction Hamiltonian? It seems that if > >it did we'd be in the position of having to do stat mech on the > >interaction, which would again involve assumptions about chaos and > >averaging? I think we might run into Chris'es "cat in the tree" > >problem. > > The argument that is made is that the 'classical' world emerges from > the quantum, in the sense that the quantum is more fundamental. But > when we look into it, we find that Bohr was quite perceptive with > his Correspondence Principle: since we are essentially 'classical' > beings, we have to start with classical concepts even to begin to > build a quantum theory. I doubt that it would be even possible to > construct a quantum theory /ab initio/, without reference to > classical ideas. > Quantum theory ab-initio is fine, but I strongly suspect you will never get the classical world emerging out of it with some extra ingredient (which I believe is your critique). That extra ingredient I think has been identified as the subjective - and the subjective is possibly constrained to having to implement classical computation (Bruno's idea), which explains why it is the classical world that emerges from the quantum, not something else. -- ---------------------------------------------------------------------------- Prof Russell Standish Phone 0425 253119 (mobile) Principal, High Performance Coders Visiting Professor of Mathematics hpco...@hpcoders.com.au University of New South Wales http://www.hpcoders.com.au ---------------------------------------------------------------------------- -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
