Re: [Phys-l] Arrow of Time Issue (correction )

[Spinozalens@aol.com]

In a message dated 3/8/2012 10:44:54 A.M. Eastern Standard Time,  
Spinozalens@aol.com writes:

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 computerize  I'll send this  write 
up  to any  
interested person. These papers listed below  invoke a Bi verse boundary 
condition, first  proposed 
by  Sakharov. This idea has also been proposed in terms  of inflation 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 inflatin
g) 
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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