On Saturday, March 7, 2020 at 2:47:15 PM UTC-6, Brent wrote: > > > > On 3/7/2020 4:05 AM, Lawrence Crowell wrote: > > On Friday, March 6, 2020 at 7:51:10 PM UTC-6, Brent wrote: >> >> >> >> On 3/6/2020 3:55 PM, Bruce Kellett wrote: >> >> On Sat, Mar 7, 2020 at 10:17 AM John Clark <[email protected]> wrote: >> >>> This video just went online, I thought it was excellent: >>> >>> Parallel Worlds Probably Exist. Here’s Why >>> <https://www.youtube.com/watch?v=kTXTPe3wahc> >>> >>> John K Clark >>> >> >> Impressive graphics, but the same old....same old.... >> >> Bruce >> >> >> You might find this interview of Sean Carroll more interesting. He's >> aware of the problems with MWI and is fairly candid about it even though he >> likes it. Start at 54:00 to skip all the explanation of QM. >> https://www.youtube.com/watch?v=XjDiOu5__oA >> >> Brent >> > > The question on whether QM has an infinite or finite Hilbert space can be > addressed with the existence of event horizons. The cosmological event > horizon puts a limit. Consider a Planck scale quantum state that has been > redshifted to the cosmological horizon scale. This is a ratio of around > 10^{60} and from the FLRW this leads to a distance of around 1800 billion > light years. Since this defines a finite region this means the Hilbert > space accessible to any observer is finite, even if enormously large. Even > if the global Hilbert space is infinite, observers are fundamentally local > and the amount of quantum information accessible is finite. To take this > further, with inflationary cosmology the cosmological event horizon on the > high energy vacuum was only 10^2 or 10^3 Planck units of radius the large > number of quantum states that appear accessible on the low energy physical > vacuum are an enormous redundancy. > > At around 1:14 Carroll gets to brass-tacks on this issue with the horn. > The idea in MWI is then "everything happens that can happen," which some > people find difficult. In effect even though there is a probability weight > with each possible branch, an observer that witnesses a highly improbable > quantum event has this sense they are on a split branch and have no post > collapse information about a prior probability. MWI has the concept of a > cosmic wave function, but this sense of there being only two outcomes > reflects a lack of counterfactual definite reasoning tied to objective > probabilities. As a result these branches occur in a certain nonlocal > sense. > > Is this at all demonstrable? No, counterfactual definite reasoning and the > existence of a global wave are not demonstrable. There are forms of > horizons, in general a form of epistemic horizon, which are a > generalization of the inaccessibility of information in QM and with general > relativity and event horizons. So whether there is or is not a global > cosmological wave function is a metaphysical choice of an analyst. > Generally ψ-ontological interpretations have a global cosmic wave function, > but a subset of those with a hidden variable interpretation also have > counterfactualism. > > As Carroll points out there are four major types of interpretations, MWI > and deBroglie-Bohm, both ψ-ontic but with and without counterfactualism, > and Qubism and dynamic collapse that are ψ-epistemic. Qubism has some > advantages, but it leads to odd ideas that are almost solipsism. Dynamic > collapse and related idea of stochastic QM have wave functions just > spontaneously collapse and the more entangled the system is the more > frequent this will happen. > > > Isn't the Transactional Interpretation a kind of dynamic collapse, in > which a possibility is actualized by the absorbtion of energy or > information? > > Brent > > It is not an idea I know that well. The idea is that a quantum wave ψ is the time forwards state and its complex conjugate ψ* is advanced. It is a sort of quantum variant on the Feynman-Wheeler absorber theory. The collapse of a wave function is then in some ways real and not swept away as a phenom as in MWI.
These quantum interpretations are emerging and multiplying like bunnies. As I see it if these are a manifestation of a qubit version of Turing's theorem these are then incomplete and auxiliary axioms. Frankly the best thing to do is to give light consideration to any of these and mostly shut up and calculate. LC > I have certain issues there with how to treat coherent states such as with > lasers or with condensates of states. In general one can pick and choose, > and these are available for those who want to think of certain problems in > a certain framework. I think frankly that QM decoherence, and by extension > a measurement, amounts to a sort of Gödel numbering of quantum bits by > quantum bits. I see all of these interpretations of QM then as a sort of > incompleteness or inconsistency that results by trying to impose a certain > question or proposition on QM that is not decidable. > > LC > -- > 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] <javascript:>. > To view this discussion on the web visit > https://groups.google.com/d/msgid/everything-list/a65f1c1d-2d39-4690-81fb-be2dd41e6ecf%40googlegroups.com > > <https://groups.google.com/d/msgid/everything-list/a65f1c1d-2d39-4690-81fb-be2dd41e6ecf%40googlegroups.com?utm_medium=email&utm_source=footer> > . > > > -- 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 view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/bae1af82-729e-40a9-aad5-2add7563a262%40googlegroups.com.
