Stephen P. King (stephenk1@home.com)
Wed, 29 Sep 1999 19:25:59 -0400
Dear Lance,
I was trying to get some thinking focussed on the key issue: time and
how it is thought of. I too am interested in how Hitoshi contrasts his
notions with those of people like Baez. One problem that I see, is that
it is assumed that there exist only one space-time manifold in which all
observers are embedded. This is a very old notion and remains
unquestioned!
We need to consider the implications of LS theory with regards to this!
I believe that each LS would define its own space-time, both in terms of
the causal behavior of its observations and the group theoretical
behavior thereof. We can take a clue from the ideas were geometries were
defined by the algebraic properties of systems and not by some a priori
given.
We need to talk about clocking! We need to figure out a clear and
concise definition that is applicable at any level of complexity. I feel
that it will relate directly to what observation is in a
non-anthropocentric fashion. :-)
I cut and pasted your post [time 833]] below.
Lancelot Fletcher wrote:
>
> Dear Stephen,
>
> > -----Original Message-----
> > From: Stephen P. King [mailto:stephenk1@home.com]
> > Sent: Wednesday, September 29, 1999 6:50 AM
> > To: Lancelot Fletcher
> > Subject: Re: FW: [time 830] Re: Does a fundamental time exist in GR and
> > QM? The thinking of others...
> >
> >
> > Dear Lance,
> >
> > Here is the Deja-News URL for the thread. It is titled: "Does a
> > fundamental time exist in GR and QM?".
> >
>
> As you have most likely noticed by now, I already found that thread via
> deja-news myself. I found the message you posted rather interesting,
> although I am still not clear why you chose that particular one to post. I
> have not had a chance to read the entire thread, but, as I said in [time
> 833], I think the first message in the thread bears some resemblance to
> some of the ways in which Hitoshi has formulated his project. By posting
> it on Hitoshi's time list I am hoping to prompt Hitoshi to say something
> that would clarify the background of his thinking.
>
> Lance
Subject: [time 833] RE: [time 830] Re: Does a fundamental time exist in
GR and QM? The thinking of
others...
Date: Wed, 29 Sep 1999 02:09:40 -0500
From: "Lancelot Fletcher" <lance.fletcher@freelance-academy.org>
To: <stephenk1@home.com>, <time@kitada.com>
Stephen,
> -----Original Message-----
> From: owner-time@kitada.com [mailto:owner-time@kitada.com]On Behalf Of
> Stephen Paul King
> Sent: Tuesday, September 28, 1999 9:28 PM
> To: time@kitada.com
> Subject: [time 830] Re: Does a fundamental time exist in GR and QM? The
> thinking of others...
I was a little puzzled about why you re-posted that message by John Baez
which was originally posted on Aug. 12 on the sci.physics.research
newsgroup as message 112 in a thread containing 119 messages. Out of
curiosity I tracked down the first message in that thread, from Paul
Stewart Snyder on Aug. 6, and I have copied it below. It seems to me
that
some of this, especially the second paragraph, resembles Hitoshi's
approach
in ways that might be worth exploring.
Lance
===================================
From: "Paul Stewart Snyder" <ps@ws5.com>
Subject: Does a fundamental time exist in GR and QM?
Date: 06 Aug 1999 00:00:00 GMT
Message-ID: <rqe8crihq1tcq6@corp.supernews.com>
Approved: mmcirvin@world.std.com (sci.physics.research)
Sender: mmcirvin@world.std.com (Matthew J McIrvin)
Organization: Posted via Supernews, http://www.supernews.com
Newsgroups: sci.physics.research
I have tried to digest the basic information in the recent threads about
spacetime in GR. To me the most interesting ideas follow from what Carlo
Rovelli suggested in 1991 (Physical Review D43, 442), that in GR time
should be treated as a derived and not a fundamental quantity. In
extending this
to the quantum world, he argues that "in the absence of a fundamental
time and
of an exact Schrodinger equation, there are gauge invariant observables,
that commute with the hamiltonian constraint, which describe evolution
with
respect to physical clocks. The observables are self-adjoint operators
on
the space of the solutions of the Wheeler-DeWitt equation.. Evolution
with
respect to physical clocks is described by self-adjoint operators
corresponding to the observables.. This extension is well-defined both
in
terms of the coherence of the formalism, and from the point of view of
the
viability of the standard probabilistic interpretation."
It seems to me that rethinking the answers to the questions about what
is
"here and now" and what is "casuality", in terms of spatial contiguity
in
an atemporal universe, might resolve some of the apparent paradoxes of
GR/QM?
Indeed, the idea of hamiltonian mechanics in a presymplectic space seems
"elegant" and, if this actually models nature, might provide a useful
way
of viewing phenomena that seem to lack temporal constraints. Are there
any
clear objections or impediments in pursuing this approach?
****
We think of a clocking as an act of observation within LS theory, as I
interprete it; so we distinguish observables from observers in the sense
of subject and object... We need to think about causality! What is
"presymplectic space"?
Later,
Stephen
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