🚀 go-pugleaf

Hi folks,

(Sorry about the new title, but the QM Kitty thread was fraying anyway... :) )

ANYONE KNOW THE BOOK TITLE?

In article <1992Oct2.171416.21445@lmpsbbs.comm.mot.com>
bhv@areaplg2.corp.mot.com (Bronis Vidugiris) writes:

> In article <1992Oct2.052956.15760@asl.dl.nec.com>
> terry@aslws01.asl.dl.nec.com (Terry Bollinger) writes:

> | ... The fact that such traces would for the most part be very difficult
> | to interpret in terms of life or death of the cat is not the issue --
> | the *potential* to recover information is all that is needed.
>
> ... Your arguments about information remind me of an argument I read a
> while back, but haven't seen on the net.  I am not sure I can do it
> justice, though.  And I've misplaced the reference (it was a semi-popular
> type book though, not rigorous or quantitative) and I don't recall it's
> title, either!

I'd be curious to know the title if you or anyone else happens to recall it.

That there are some books on such ideas doesn't surprise me that much.  But
I'm not familiar with any, and would thoroughly enjoy a chance to read a
more formal analysis of such issues.  (I'm trying to track down a copy of
that interesting-looking info-and-physics book someone mentioned.)

INFO & IRREVERSIBILITY

> However, the vague part was that since small scale events are reversible,
> and large scale events are not, it wasn't clear just what *did* constitute
> entorpy, or 'information'.  The book discussed this a fair amount - enough
> for me to realize that I didn't have a very firm grasp of the idea, and to
> get an impression that maybe there was some fundamental reason no really
> sharp line could be drawn between 'reversible' and 'irreversible' processes.

BINGO!  And exactly why I called what I said "hand wavy" and made sure I
put quotes around the statement about "solving" QM Kitty problems.  I don't
think it's necessarily all that radical to suggest that maybe, just maybe,
the QM Kitty is *not* the way the world works as we usually see it.  But
just try to quantify such a statement formally and OUCH, you get bit by
the problem of trying to define "information" itself in a way that does
not casually introduce unnecessary and unproven assumptions that simply
do not exist in either QM or thermodynamics.

OVERSIMPLIFICATION IN THE USUAL QM KITTY ANALYSIS

On the other hand, I would remain pretty firm on the point that the usual
QM Kitty problem is absurdly oversimplified in the sense of ignoring all
of the other possible "observer" paths.  Dunno why the one observer ususally
mentioned should be the only one who gets to take on the role of Breaker
of The Many States, when potentially observable information is spewing out
of the entire setup at a rate that I'd ballpark to be in the terabits per
second range as a minimum.  Why can't the flea on the cat's tail be the
observer?  Or the amoeba on the side of the box who suddenly feels a wee
little bump as the cat buys the farm and plunks over?

There's a point in the flea and the amoeba examples, and the point is that
I'm extremely dubious about QM Kitty interpretations that insist on mixing
in the idea of "consciousness" with observation.  If you drop back to the
decidely nebulous but a LOT less metaphysical concept of "information," you
no longer find yourselve in bizarre comtemplations of whether or not an
amoeba or a flea should be considered conscious or not.  If they can hold
and process information in the conventional (but ill-defined) large-world
sense, the information view holds that to be quite sufficient.

(Folks who have seen my sincere praise of Roger Penrose's ability to write
about QM will note that on issues such as "consciousness," I very much part
ways with his ideas.  I have no real idea what he was trying to tell folks
in the "consciousness" parts of The Emperor's New Mind, and frankly feel
that whatever is was could have been said a lot more concisely.  And that
I would have disagreed strongly with said concise statement.)

Another beef I have with the usual QM Kitty setup is its implicit solopsist
philosophy -- that is, that only YOU, whoever you are, who are reading this
are sufficiently "real" to act as the ultimate observer.  Maybe I'm overly
democratic about these things, but if George wants to kill/save the cat
that's just dandy with me.  (Even if George IS just an amoeba!)

INFO => FUZZY, BUT BETTER THAN TOTALLY UNQUANTIFIED "CONSCIOUSNESS" DEBATES

Sooo... bottom line:  "info" is loosey-goosey, but hey, I say it's at least
a bit of an improvement over endless argument-chains as to who the Ultimate
Observer is.  (Hey, I know!! It's DAN QUAYLE!  That MUST be why George Bush
picked him!!!)  Some schools of QM try to make the very nebulous and quite
undefined large-world concept of "consciousness" into the key for resolving
observer paradoxes.  Am I really that much more radical for proposing that
the focus be on another large-world quantity, information, that at least
can be quantified and measured in some fairly meaningful sense?  Neither
information nor consciousness can be derived from the basic laws of QM or
thermodynamics, so I'm not sure how either one rates better on that scale.

A CHALLENGE REPEATED:  HOW ABOUT PHYSICAL UNITS FOR "INFORMATION?"

I was also very much serious about whether someone out there might have any
ideas on how to link units of information to other units in physics, using
some link to, say, changes in QM interference effects.  It's an interesting
exercise, and one with some promise of real formalization, not just hand-
waving.  (Whether you would be able to get anyone to *agree* to your
formalization is another issue!)

BELL AND PARTICLE-ON-THE-PHOSPHOR-SCREEN IRREVERSIBILITY

> There were some arguments about whether a photon hitting a phosphor screen
> constituted a 'measurement' ... I was surprised to hear that some people
> felt this could in principle be 'reversed' and the photon 'unmeasured'...

I've never seen that one, but Bell gives a delightful example of how you
can extend a wavefunction analysis to include the particle traveling through
multiple screens.  You simply get a wavefunction in which the the *paths*
through the screen are what counts, rather than individual collisions with
individual atoms.  (I guess if you keep following that type of path you will
get something that has a nicely MWI flavor to it, in which whole universes
are represented as "chuncks" of the wavefunction, hmm??)


PHOTON DAMAGE TO WAVEFUNCTION INTERFERENCES -- WHAT, NO CHALLENGES?

By the way, I'm surprised no one has gone after my assertion that one photon
can do the same amount of "damage" to wavefunction interference for a massive
object as for a light one.  Isn't ANYONE going to quibble with me on that one?

Why should I have said such a thing?  Is it true, or not?  What are the
relevant issues and/or equations?

Right or wrong, it's mostly just a QM 101 issue of how the uncertainty
principle works.  Nothing terribly complex, I think.

Here's a hint:  What happens if you replace the electron in a two-slit
experiment with a muon moving about 200 times slower?

  Can you make any definitive assertions about the relationship of the
  electron and muon wavefunctions in such a case?

  Does one photon at the exit of one of the slits do the same level of
  "damage" to the wavefunction interference -- or less, or more?

  What if the muon is made to travel at the *same* velocity as the
  electron, instead of 200 times slower?

  Is there a simple way to quantify the "damage" issue for such problems?


				Cheers,
				Terry Bollinger