On Tue, Sep 27, 2011 at 11:52 PM, meekerdb <meeke...@verizon.net> wrote:

>  On 9/27/2011 9:13 PM, Jason Resch wrote:
>
>
>>  I don't think that.  I just noted it's logically possible, contrary to
>> assertions that our universe must be duplicated infinitely many times.
>
>
>  If our universe is not duplicated a huge number of times, then quantum
> computers would not work.  They rely on huge numbers of universes different
> from ours aside from a few entangled particles.  Even normal interference
> patterns are explained by there existing a huge number of very similar
> universes.
>
>
> Or by Feynmann paths that zigzag in spacetime.  Don't become to enamored of
> an interpretation.
>
>
If you assume there is a single photon interfering with itself, how  is it
that this one particle can evaluate a problem whose computational complexity
would exceed that of any conventional computer using all the matter in the
universe?


>
>
>
>>
>>
>>  However, according to Vilenkin, Greene, and
>>> Tegmark, a generic prediction of the theory of inflation is that there
>>> is an *infinite* number of Hubble volumes (what you are calling
>>> universes).  Let's call the hypothesis that all quantum-physical
>>> possibilities are realized infinitely many times "the hypothesis of
>>> Cosmic Repetition". Brian Greene argues for this hypothesis quite
>>> persuasively. He says, "In an infinitely big universe, there are
>>> infinitely many patches [i.e., Hubble volumes]; so, with only finitely
>>> many different particles arrangements, the arrangements of particles
>>> within patches must be duplicated an infinite number of times." (The
>>> Hidden Reality, pg. 33)
>>>
>>  It's plausible - but not logically required.  Suppose all the infinite
>> universes are number 1, 2, ...  Number 1 is ours.  Number 2 something
>> different.  Numbers  3,4, ...inf are exact copies of number 2.  So there are
>> only two arrangements of particles; in spite of there being infinitely many
>> universes.
>
>
>  Not logically required, but I would say it is not consistent with our
> current theories and observations.
>
>
>>
>>
>>
>>> As for the probability distribution of matter and/or outcomes, I'll
>>> let Tegmark do the explaining:
>>>
>>> "Observers living in parallel universes at Level I observe the exact
>>> same laws of physics as we do, but with different initial conditions
>>> than those in our Hubble volume.
>>>
>>
>>  This is questionable.  Most theories of the universe starting from a
>> quantum fluctuation or tunneling from a prior universe assume that the
>> universe must start very small - no more than a few Planck volumes.
>
>
>  The generalized theory of inflation is eternal inflation.  It leads to an
> exponentially growing volume which expands forever.
>
>
>>  This limits the amount of information that can possibly be provided as
>> initial conditions.  So where does all the information come from?
>
>
>  I haven't heard the theory that there is an upper bound on the
> information content for this universe set by the big bang.
>
>
> In one Planck volume there is only room for one bit.  That's the
> holographic principle.
>
>
Yet our universe appears to take more than 1 bit to describe, and it seems
to have a possibly infinite volume.


>
>
>  As to where information comes from, if all possibilities exist, the total
> information content may be zero, and the appearance of a large amount of
> information is a local illusion.
>
>
>>  QM allows negative information (hidden correlations) so that one
>> possibility is that the net information is zero or very small and the
>> apparent information is created by the existence of the hubble horizon.
>>
>>
>>  The currently favored theory is that
>>> the initial conditions (the densities and motions of different types
>>> of matter early on) were created by quantum fluctuations during the
>>> inflation
>>> epoch (see section 3). This quantum mechanism generates initial
>>> conditions that are for all practical purposes random, producing
>>> density fluctuations described by what mathematicians call an ergodic
>>> random field. Ergodic means that if you imagine generating an ensemble
>>> of universes, each with its own random initial conditions, then the
>>> probability distribution of outcomes in a given volume is identical to
>>> the distribution that you get by sampling different volumes in a
>>> single universe.
>>
>>
> That's not what ergodic means.  In the theory of stochastic processes it
> means that ensemble statistics are the same as temporal statistics.  In the
> eternal expansion theory it is not assumed that the physics is the same in
> each bubble universe.
>

This one "bubble" is infinitely big according to eternal inflation.


>   It is hypothesized that the spontaneous symmetry breaking that results in
> different coupling constants for the weak, strong, EM, and gravity forces is
> random.  That's how it provides and anthropic explanation for "fine-tuning"
> - we're in the one where the random symmetry breaking was favorable to life.
>

This is one hypothesis to explain fine tuning, I am not sure how well it is
supported.


>
>
>    In other words, it means that everything that could
>>> in principle have happened here did in fact happen somewhere else.
>>> Inflation in fact generates all possible initial conditions
>>>
>>
> But it's not initial conditions.  It's random symmetry breaking.
>
>
>    with non-zero probability, the most likely ones being almost uniform
>>> with fluctuations at the 10^5 level that are amplified by
>>> gravitational clustering to form galaxies,
>>> stars, planets and other structures. This means both that pretty much
>>> all imaginable matter configurations occur in some Hubble volume far
>>> away, and also that we should
>>> expect our own Hubble volume to be a fairly typical one — at least
>>> typical among those that contain observers.
>>
>>
> But this sort of undercuts the need for the anthropic explanation.  If our
> universe is "typical" (i.e. probable) then there's no need to invoke
> infinitely many others to avoid the "fine-tuning" problem.  You could just
> say it's the more probable one and so it's the one that happened.
>
> Brent
> "If an explanation could easily explain anything in the given field, then
> it actually explains nothing."
>
> Which explanation is this referring to?

Jason

-- 
You received this message because you are subscribed to the Google Groups 
"Everything List" group.
To post to this group, send email to everything-list@googlegroups.com.
To unsubscribe from this group, send email to 
everything-list+unsubscr...@googlegroups.com.
For more options, visit this group at 
http://groups.google.com/group/everything-list?hl=en.

Reply via email to