On Tuesday, September 17, 2019 at 11:46:35 PM UTC-5, Bruce wrote: > > On Wed, Sep 18, 2019 at 10:37 AM 'Brent Meeker' via Everything List < > everyth...@googlegroups.com <javascript:>> wrote: > >> On 9/17/2019 3:49 PM, Bruce Kellett wrote: >> >> On Wed, Sep 18, 2019 at 3:01 AM smitra <smi...@zonnet.nl <javascript:>> >> wrote: >> >>> On 17-09-2019 13:32, Bruce Kellett wrote: >>> > >>> > So why do all Everettians have to add so many additional assumptions >>> > in order to pretend to get out the Born rule? >>> > >>> >>> Simply assuming the special case of the Born rule that measuring a >>> system in an eigenstate of an observable will yield the eigenvalue of >>> that eigenstate with certainty, is enough. >> >> >> Where did the concept of an observable as an operator in a Hilbert space, >> and the idea that measurements correspond to the action of that observable >> on the state, giving a result that is the eigenvalue corresponding to the >> projected eigenvector, come from? >> >> >> The operator should be expressible in terms of the Hamiltonian of the >> measuring instrument and its interaction with the system. But nobody tries >> to write down the Hamiltonian of the instrument; they just look at what >> it's supposed to measure classically and then they write an abstract >> operator that does that. >> > > So it is something added to the supposed "minimal QM" of the Schrodinger > equation. The eigenvector/eigenvalue link is pretty well established. Zurek > has a good argument to derive this. > > Bruce >
The Zurek (QD) theory is a very good (in my view) framework to consider. A useful antidote to MWI. https://arxiv.org/abs/1807.02092 *Quantum Theory of the Classical: Quantum Jumps, Born's Rule, and Objective Classical Reality via Quantum Darwinism* Wojciech Hubert Zurek (Submitted on 5 Jul 2018) Emergence of the classical world from the quantum substrate of our Universe is a long-standing conundrum. I describe three insights into the transition from quantum to classical that are based on the recognition of the role of the environment. I begin with derivation of preferred sets of states that help define what exists - our everyday classical reality. They emerge as a result of breaking of the unitary symmetry of the Hilbert space which happens when the unitarity of quantum evolutions encounters nonlinearities inherent in the process of amplification - of replicating information. This derivation is accomplished without the usual tools of decoherence, and accounts for the appearance of quantum jumps and emergence of preferred pointer states consistent with those obtained via environment-induced superselection, or einselection. Pointer states obtained this way determine what can happen - define events - without appealing to Born's rule for probabilities. Therefore, Born's rule can be now deduced from the entanglement-assisted invariance, or envariance - a symmetry of entangled quantum states. With probabilities at hand one also gains new insights into foundations of quantum statistical physics. Moreover, one can now analyze information flows responsible for decoherence. These information flows explain how perception of objective classical reality arises from the quantum substrate: Effective amplification they represent accounts for the objective existence of the einselected states of macroscopic quantum systems through the redundancy of pointer state records in their environment - through quantum Darwinism. @philipthrift -- 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 view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/ee4aa20d-b9bd-407b-b985-3ab107e0f7b2%40googlegroups.com.
