On Wednesday, June 6, 2018 at 1:17:22 AM UTC, Brent wrote: > > > > On 6/5/2018 5:05 PM, Bruce Kellett wrote: > > From: <[email protected] <javascript:>> > > > On Tuesday, June 5, 2018 at 7:02:11 PM UTC, Brent wrote: >> >> >> >> On 6/5/2018 2:48 AM, [email protected] wrote: >> >> *One objective was to convince myself whether the wf you have written for >> decoherence makes any sense. Originally I thought one needed mutual >> interference of all components for it to be viable. I doubted whether each >> component interferes with the others in your proposed wf because the |e> >> wave functions have no well defined deBroglie wave lengths (which I thought >> were necessary for a valid quantum superposition).* >> >> >> de Broglie wave lengths are useful when thinking about a particle, but a >> complex system with many degrees of freedom has many different energy >> levels available to it and each one evolves with a different frequency. So >> the de Broglie wavelength is not very useful. >> >> Brent >> > > *Agree. That's what Bruce wrote, in effect, when he noted that the macro > states in the superposition for decoherence are just symbols for the > multitude of entanglements, each presumably with its own deBroglie wave > length**. But now I don't see the problem -- the weird implications > --with these superpositions involving macro systems as dependent on > interference. If the S Cat's wf can be written as a sum of two states, each > entangled with the radioactive source, the implication is that the Cat is > simultaneously alive and dead. It's like a simple vector in the plane -- > those pointy things -- which can be written as the sum of a horizontal and > vertical vectors (or a non orthogonal basis). If it can be written as a > sum, it can be interpreted as manifesting both vectors in the sum > simultaneously. So, if you want to write state vectors to include > entanglements with macro systems, you will get cats that are alive and dead > simultaneously, and in the decoherence case, you'll ger copies of this > universe, inclusive of copies of observers, etc. That was Schrodinger's > point; the fallacy of entangling quantum and macro states in one wf. AG* > > > Yes, Schrödinger's original intention with the cat scenario was to provide > a *reductio ad absurdum*: the conclusion of cats being simultaneously > alive and dead was patently absurd. In later life Schrödinger regretted > introducing his wave equation. His idea had been to formulate quantum > phenomena in terms of something easily visulizable in a classical way, such > as wave motion. This was as an antidote to what many saw as the increasing > obscurantism of Bohr and the Copenhagen school. However, he was > disappointed by the results, and by the fact that his wave equation became > the standard way of thinking about quantum processes. Schrödinger was > undoubtedly aware that there were other ways of doing quantum calculations > than in terms of his wave equation; Heisenberg matrix mechanics was already > available, then there is Schwinger's mathematical approach, path integral > approaches, and so on. None of which need mention a wave or a wave > equation. They all give the same results for quantum probabilities so since > they were equivalent in this sense, they were, according to the metaphysics > of the time, all considered to be the same theory. > > But it is doubtful if they are all actually the same theory, since they > seem to imply different ontologies. Schrödinger's wave mechanics has led to > the reification of the wave function itself, and the result is many worlds > theory. But if you don't have a wave equation and work only with matrices, > there is no reason to postulate any multiplicity of worlds. The model that > you use for calculations in the theory implies an ontology, and not all > implied ontologies are the same, or even equally useful. People are all to > ready to believe that the simplest ontology of their model is what is > "really real". But they are generally mistaken, as the negative induction > of scientific realism points out. > > Bruce > > > Well said. >
Ditto. AG > Bohmian QM also gave the same answers as CI, but has a different ontology > and is deterministic. It's randomness comes from ignorance of the initial > state. CI postulates intrinsic randomness. MWI is deterministic but > postulates ignorance of where you'll end up. QBism assumes personal > randomness. > > Brent > -- 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 [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
