On Apr 18, 10:41 am, Remus Shepherd <re...@[EMAIL PROTECTED]
> wrote:
> I've been toying with Zeno's effect and its repercussions in my
written
> SF for a while, so this article caught my eye:
>
> http://arxivblog.com/?p=370
Well, _that's_ medium to well-done bizarre.
(For the benefit of Damien Valentine, yes, I read the paper and some
other stuff on the subject; apparently the basic concept isn't new,
but the connection to magnetosensing is.)
> Basically, Zeno's effect says that because quantum systems only
change
> their wave states between observations, constant observation can delay
the
> effects of quantum interactions. If you watch that tritium atom
constantly,
> it will *never* decay.
That doesn't quite match what I read. The tritium atom can only
decay between observations which not only take a finite, nonzero
amount of time but also must be separated by a finite, nonzero amount
of time. The basic concept hinges on taking both quantities as close
to zero as you'd like, leaving no time interval for the decay to
occur.
I'll point out that the Wikipedia article on the subject mentions
that:
'In the context of this effect, an "observation" can simply be the
absorption of a particle, with no observer in any conventional sense.'
Particle interactions like emissions and absorptions are time-framed
by the forces by which they interact and the characteristic limits of
their response times to those forces.
ISTM that if we hadn't developed the idea of Planck time before,
this would have led us to it.
> The paper claims that birds use this effect to delay
> a chemical reaction long enough to sense the Earth's magnetic field.
Yup.
> (Incidentally, I'm intrigued that this happens in avian retinas. Do
> birds actually *see* magnetic north and south?? The mechanism creates a
bias
> in the outcome of a chemical reaction. Could birds see everything to
the
> north tinted one color, and everything to the south tinted a different
hue?)
The arxiv article at:
http://arxiv.org/ftp/arxiv/papers/0804/0804.2646.pdf
refers specifically to the Earth's magnetic field's effect on
cryptochrome, a flavoprotein sensitive to blue light and involved in
circadian 'clock' entrainment among other things, but AFAICT not
specifically to seeing. So, mu.
Oh, also in reptiles and amphibians. Wow. Mammals possibly have the
ability in latent form hidden in our genome. Double wow.
> I'm trying to extrapolate this mechanism and see what falls out of
it.
> Imagine an alien metabolism (or very high-tech appliance) capable of
deciding
> when and how quantum states change. Could it intake radioactive
isotopes and
> use them as a safe, on-demand power source? Photoresistant surfaces
that
> do not interact with light? Can a nervous system evolve using
controlled
> electron tunnelling as a trans****t mechanism?
Hrm. Asimov's Golden Goose?
> I'm lapsing into wild speculation mode, I know. To me, this news is
> very cool fodder for daydreaming.
Oh, definitely.
However unless a mechanism can completely sidestep Heisenberg and
Planck, there'll be limits. Frinst bird "magnetovision" has a built-in
15-degree error cone, which is pretty bad but not enough to make it
useless.
Mark L. Fergerson
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