On Wednesday, November 29, 2017 at 4:40:36 PM UTC-6, Bruce wrote: > > On 30/11/2017 5:31 am, John Clark wrote: > > On Tue, Nov 28, 2017 at 10:59 PM, Bruce Kellett <bhke...@optusnet.com.au > <javascript:>> 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, > and there is currently no theory as to how this would change in a unitary > manner. >
It is interesting you would say this. I wrote a paper nearly 30 years ago on something like this. The idea was with the renormalization of the Planck constant ħ → ħ*, that was of the form ħ* ~ ħcosh(gs), where g is gravity based on g = -∇_aK^b∇^aK_b. This renormalized Planck constant is not an actual change in the constant, but it is a case where the time dilation and lensing of observed processes have the effect of freezing out quantum fluctuations near an event horizon. The transformation is not unitary, but since it is due to a frame transformation in spacetime it does not imply the sort of damage thought of with information loss. The main dimensionless constant is the fine structure constant α = e^2/ħc. The Planck constant is a conversion factor between momentum and length (wavelength) and the speed of light is a conversion factor between distance and time. I think on a frame bundle or an inertial frame these are absolute constants. This means if the fine structure constant varies it must be the electric charge. This is fine with charge renormalization, and potentially during the inflationary period it was not a set constant that varied with the vacuum energy. LC > > > >> > 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 > > between quantum and non-quantum events? A unstable atom has a 50% chance > of decaying and producing a easily detectable high speed electron, if the > electron is detected a computer controlled robot arm turns my coin to > heads, if it detects no electron it turns my coin to tails. > > > Of course, if you set up a situation in which a quantum event is amplified > to give a difference in macroscopic outcomes, such as in Schrödinger's cat, > then you can say that the macroscopic uncertainty has a quantum origin. But > the majority of quantum events are not amplified in this way -- they simply > occur randomly in large numbers so that the expectation value is unaffected > by individual uncertainties. > > > > Also, in the Level I multiverse it is quite unlikely that the initial > conditions could differ to an extent such that everything was identical in > the two worlds up to your coin toss. > > > Quite > unlikely > events are going to happen if the number of universes is large enough, > and if there are a infinity of worlds then anything with a non-zero > probability is certain to happen in some universe. > > > Except events of measure zero. > > ... -- 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 https://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
