Re: [Phys-l] Arrow of Time Issue

[Spinozalens@aol.com]

Here are some interesting papers on the AOT in terms of Eternal  Inflation. 
I have written about this for another list but this list can't handle  the 
math notation and no one wants to read computize  I;ll send to any  
interested person. These papers invoke a Biverse boundary condition, first  proposed 
by Sakharov , and in terms the inflation model proposed by my friend Dr  
Vic Stenger in several of his books. This allows an essentially Steady State  
cosmology even though inflation is not past complete, that is it must have 
begun  at some point in time. 
 
 
Bob Zannelli 
 
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Inflation without a beginning: a null boundary proposal  
Authors: _Anthony  Aguirre_ 
(http://arxiv.org/find/gr-qc/1/au:+Aguirre_A/0/1/0/all/0/1) , _Steven  Gratton_ 
(http://arxiv.org/find/gr-qc/1/au:+Gratton_S/0/1/0/all/0/1) 
(Submitted on 10 Jan 2003 (_v1_ (http://arxiv.org/abs/gr-qc/0301042v1) ), 
last revised 28 Mar 2003  (this version, v2))

Abstract: We develop our recent suggestion  that inflation may be made past 
eternal, so that there is no initial  cosmological singularity or 
"beginning of time". Inflation with multiple vacua  generically approaches a 
steady-state statistical distribution of regions at  these vacua, and our model 
follows directly from making this distribution hold  at all times. We find that 
this corresponds (at the semi-classical level) to  particularly simple 
cosmological boundary conditions on an infinite null  surface near which the 
spacetime looks de Sitter. The model admits an  interesting arrow of time that 
is well-defined and consistent for all physical  observers that can 
communicate, even while the statistical description of the  entire universe admits a 
symmetry that includes time-reversal. Our model  suggests, but does not 
require, the identification of antipodal points on the  manifold. The resulting 
"elliptic" de Sitter spacetime has interesting  classical and quantum 
properties. The proposal may be generalized to other  inflationary potentials, or 
to boundary conditions that give semi-eternal but  non-singular cosmologies. 
 
 
_http://arxiv.org/pdf/gr-qc/0301042v2.pdf_ 
(http://arxiv.org/pdf/gr-qc/0301042v2.pdf) 
 
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Steady-State Eternal Inflation  
Authors: _Anthony  Aguirre_ 
(http://arxiv.org/find/astro-ph/1/au:+Aguirre_A/0/1/0/all/0/1) , _Steven  Gratton_ 
(http://arxiv.org/find/astro-ph/1/au:+Gratton_S/0/1/0/all/0/1) 
(Submitted on 9 Nov 2001 (_v1_ (http://arxiv.org/abs/astro-ph/0111191v1) ), 
last revised 22 Feb  2002 (this version, v2))

Abstract: Since the  advent of inflation, several theorems have been proven 
suggesting that  although inflation can (and generically does) continue 
eternally into the  future, it cannot be extended eternally into the past to 
create a  ``steady-state'' model with no initial time. Here we provide a 
construction  that circumvents these theorems and allows a self-consistent, 
geodesically  complete, and physically sensible steady-state eternally inflating 
universe,  based on the flat slicing of de Sitter space. This construction 
could be  used as the background space-time for creation events that form  
big-bang-like regions, and hence could form the basis for a cosmology that  is 
compatible with observations and yet which avoids an initial singularity  
or beginning of time. 

 


                _http://arxiv.org/pdf/astro-ph/0111191v2.pdf_ 
(http://arxiv.org/pdf/astro-ph/0111191v2.pdf) 
 
 
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Eternal Inflation, past and future  
Authors: _Anthony  Aguirre_ 
(http://arxiv.org/find/hep-th/1/au:+Aguirre_A/0/1/0/all/0/1) 
(Submitted on 4 Dec 2007)

Abstract: Cosmological inflation, if it  occurred, radically alters the 
picture of the `big bang', which would merely  point to reheating at the end of 
inflation. Moreover, this reheating may be  only local, so that inflation 
continues elsewhere and forever, continually  spawning big-bang-like regions. 
This chapter reviews this idea of `eternal  inflation', then focuses on 
what this may mean for the ultimate beginning of  the universe. In particular, 
I will argue that given eternal inflation, the  universe may be free of a 
cosmological initial singularity, might be eternal  (and eternally inflating) 
to the past, and might obey an interesting sort of  cosmological 
time-symmetry. 
 
_http://arxiv.org/pdf/0712.0571v1.pdf_ 
(http://arxiv.org/pdf/0712.0571v1.pdf) 


 
 
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In a message dated 3/7/2012 10:27:22 P.M. Eastern Standard Time,  
jlu@hep.anl.gov writes:

I don't  understand you.  Let me try to explain why in two ways:
"If time is increasing" suggests that "time" is defined in such a 
way that  it could be non increasing.  "Time" is not so defined.  We define 
 
"time" by findng a periodic phenomenum, and then counting periods.   The 
count always increases - by definition.  "If time is increasing"  is 
logically like saying "if four is greater than three".  But four  is 
defined as three plus one.  So the "if" in the statement is  surplusage; 
there is no laternate possibility.  Same with  "time".  We define it so 
that there is no alternate  possibility.
Regards,
Jack

"Trust me.  I have a lot of experience at  this."
General Custer's unremembered message to  his men,
just before leading them into the  Little Big Horn Valley




On Wed, 7 Mar 2012, Bennett Sessa  wrote:

> That is my understanding. If time is increasing then  entropy must always 
increase. If time decreases Clausius equality and the  entropy equation 
show that entropy should decrease, but we know this to be  impossible, 
therefore time cannot decrease. CPT symmetry shows that time is  however reversible.
> On Mar 6, 2012, at 9:52  PM, Jack Uretsky <jlu@hep.anl.gov> wrote:
>
> > Hi  Bennet-
> >    I'm not sure I understand your  argument.
> >    As I see it, "time:" by definitiion, can  only "go forward", so
> > that gives a meaning to the phrase "go  forward".  So the statement that
> > entropy can only increase,  means to me that: as iime increases, entropy
> > increases.  Do  you have a different understanding?
> >         Regards,,
> >         Jack
> >
> > "Trust  me.  I have a lot of experience at this."
> >       General Custer's unremembered message to his men,
> >   just before leading them into the Little Big Horn  Valley
> >
> >
> >
> >
> > On Tue, 6  Mar 2012, Bennett Sessa wrote:
> >
> > > The second law of  thermodynamics says that entropy must always 
increase or remain constant,  therefore time must always increase (go forwards). 
CPT symmetry says that  charge, parity, and time are all reversible, therefore 
time can travel  forwards and backwards. We have experimental data showing 
both to be true, yet  have no idea how thy are  related.
> > > On  Mar 6, 2012, at 9:28 PM, Jack Uretsky <jlu@hep.anl.gov>  wrote:
> > >
> > > > Hi  Bennet-
> > > >   I would like to hear (see) your  descriptiion of the so-called
> > > > "dispute".  This is my  appreciation of your posting.
> > > >         Regards,
> > > >    Jack Uretsky
> > > >
> > > > "Trust me.  I have a  lot of experience at this."
> > > >        General Custer's unremembered message to his men,
> > > >   just before leading them into the Little Big Horn  Valley
> > > >
> > > >
> > > >
> > > >
> > > >  On Tue, 6 Mar 2012, Bennett Sessa  wrote:
> > > >
> > > > > > > >    This is my first time posting in Phys-l, C.V. Britton 
recommended I join. I am  13 years old and have a knowledge of everything from 
calculus I up to some  differential equations. In my spare time I solve equations 
and teach myself  new principles on the whiteboard I have in my room. I have 
been researching  physics for a few years  now.
> > > > > > > >    I believe I have a plausible solution to the dispute between 
CPT symmetry and  the second law of thermodynamics. I believe time to be a 
conservative,  connected, four-vector quantity and the quintessence (dark 
energy) to be the  scalar quantity. In short I would be trying to find some sort 
of Lagrangian to  describe the vector potential of time, therefore 
describing the laplacian  which should be equal to zero if the field is  irrotational.
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