RE: [asa] Many Worlds - Quantum Mechanics

First, one doesn't need a multiverse in order to have time travel. There are several ways (tachyons, "time machine" solutions of Einstein's equations, hydrodynamic waves in dark energy, advanced potentials in electrodynamics) which _might_ make it possible to send signals into the past. Second, multiple time dimensions don't seem to be possible in string theories with extra dimensions - - which of course doesn't mean that they aren't possible in _any_ theory.

Shalom,
George

---- James Patterson <james000777@bellsouth.net> wrote:
> There seems to be a commonality...if multiverses can allow one to time-travel (other than the one way travel we have now of course), and multiple time dimensions can allow one to time travel, then are multiverses equivalent on some level with multiple (at least two) time dimensions? I think that there are 10 or 11 dimensions (I can never remember) and we are only in 4 of them...could it be that what physicists are seeing in their equations is this effect of multiple time dimensions?
>
> -----Original Message-----
> From: gmurphy10@neo.rr.com [mailto:gmurphy10@neo.rr.com]
> Sent: Monday, February 02, 2009 9:47 AM
> To: asa@calvin.edu; James Patterson
> Subject: Re: [asa] Many Worlds - Quantum Mechanics
>
> The many worlds of interpretation (MWI) of quantum mechanics, introduced by John Wheeler's student Hugh Everett in the mid 50s, is _one_ possible interpretation of quantum theory. In particular, it is one way of understanding what happens when a measurement is made on a system. Instead of the state of the system (i.e., its wave function) collapsing to one in which the measured quantity has a definite value (as in the Copenhagen interpretation), there in in MWI a split in different worlds, in each of which the system has one of its possible values. (& in each world there is the observer observing that value.)
>
> As I said, this is one possible interpretation. It is of particular interest if one wants to apply quantum theory to the entire universe, for then there is no "outside" for a Copenhagen type observer. But partisans of MWI (e.g., Tipler), sometimes overstate the case & suggest that quantum cosmology _requires_ MWI.
>
> It's also worth noting that the idea of a splitting worlds in MWI, like that of the collapse of the wave function in the more traditional approach, is a _postulate_, not something that is proven on the basis of other assumptions.
>
> I'll mention again the paper on various parallel world ideas (including MWI) & theology that I gave at the 1987 ASA meeting. I'll be glad to send a copy to anyone who gives me a snailmail address, though at present delivery will be delayed somewhat.
>
> As to the time travel issues discussed in the link James has given, I think that MWI is a solution to a non-problem. The so-called "grandfather paradox" really arises from the assumption that _if_ I could travel into the past I could kill my grandfather before my father was conceived. I.e., the idea of alternate worlds is taken for granted. But if the past is fixed then I just can't do it. I can't kill my grandfather because I didn't. Nahin's book _Time Machines_ provides a good discussion of this & other matters related to time travel. (Portions of this book, including - if I remember correctly - treatment of this "paradox," arae available on Google.)
>
> Shalom
> George
> ---- James Patterson <james000777@bellsouth.net> wrote:
> > These three references here raise a question for me in regard to quantum
> > physics...how popular and accepted is this "Many Worlds" concept? It appears
> > to have been around for at least 50 years.
> >
> >
> >
> > 1. Wiki on Many-worlds <http://en.wikipedia.org/wiki/Many_worlds>
> > interpretation "The many-worlds interpretation or MWI (also known as the
> > relative state formulation, theory of the universal wavefunction, parallel
> > universes, many-universes interpretation or just many worlds), is an
> > interpretation of quantum mechanics.".
> >
> >
> >
> > 2. Parallel universe proof boosts time travel hopes
> >
> > By Roger Highfield - Last Updated: 10:46AM BST 24 Sep 2007
> >
> > "Parallel universes really do exist, according to a mathematical discovery
> > by Oxford scientists that sweeps away one of the key objections to the mind
> > boggling and controversial idea..." Read
> > <http://www.telegraph.co.uk/scienceandtechnology/science/sciencenews/3307757
> > /Parallel-universe-proof-boosts-time-travel-hopes.html> more
> >
> >
> >
> > 3. Also - a book by Frank Tipler - "The Physics of Christianity" - which I
> > confess I can't understand all of - but he professes to be both a Christian
> > and to believe in multiple universes.
> >
> >
> >
> > JP
> >
>
>
>
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Received on Thu Feb 5 10:01:11 2009