On Friday, December 1, 2017 at 9:05:21 AM UTC, [email protected] wrote: > > > > On Wednesday, November 29, 2017 at 10:40:36 PM UTC, Bruce wrote: > > On 30/11/2017 5:31 am, John Clark wrote: > > On Tue, Nov 28, 2017 at 10:59 PM, Bruce Kellett <[email protected]> > wrote: > > > > > I see no reason all the Everett worlds have the same physics, > > > > > Everettian worlds follow from assuming that the Schrödinger equation > applies everywhere without exception, so that all physical evolution is > unitary. A change in the underlying physics -- such as a change in the > value of fundamental constants, Planck's constant or Newton's constant for > example -- would not be unitary, so cannot occur in MWI. > > > > Why can't it be unitary?? Show me why if > > Newton's constant had any value other than > > 6.754* 10^-11 m3 kg^−1 s^−2 > > the sum of all quantum probabilities would no longer add up to exactly 1. > If you can really do that then you've just derived Newton's constant > directly from first principles and you should but a ticket to Stockholm > right now because you're absolutely certain to win the next nobel Prize. > > > Although unitarity does mean that probabilities always sum to unity, that > is a consequence of unitary evolution, not a definition of it. A unitary > transformation is one that can be reversed: so the unitary operator U can > be written as exp(-iH), for example, and the complex conjugate (or the > adjoint for hermitian operators) is the inverse transformation. > > So for changes in constants to be unitary, there needs to be a hermitian > operator that brings about these changes. But changes in constants only > make sense for dimensionless constants such as the fine structure constant, > > > *From a naive pov one could conjecture that the SoL could change even > though it's not a dimensionless quantity. ISTM the conclusion of an > unchanging SoL is forced on us since a meter is now defined as the distance > light travels in a second, where distance is defined in terms of the SoL. I > mean to say the current definitions of second and meter seem based on the > assumption that the SoL is an unchanging universal constant. Is this not > circular reasoning? AG* >
*Using the current definitions of meter and second, if the SoL slowed, wouldn't the meter shorten (being the distance light travels in some fraction of a second), making the slowing undetectable? Wouldn't the "duration" of the second remain unchanged in this scenario, being some fixed number of oscillations of a cesium atom? TIA, AG* > > > and there is currently no theory as to how this would change in a unitary > manner. > > > >> > lets assume you're right, then the string theory multiverse must be larger > than the many worlds multiverse incorporating everything in Everett's > version and MORE; after all if it contains universes with radically > different laws of physics it must also contain more modest things like a > world where my coin came up heads instead of tails. > > > > > I would suggest that there is no such world. Whether a coin comes up head > or tails on a simple toss is not a quantum event; > > > Do you actually think reality can be neatly divided > > > ... -- 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.
