[extropy-chat] time, age

[scerir]

Someone wrote about biological ageing and physical time(s)
http://www.phys.uu.nl/~wwwgrnsl/jos/publications/aging.htm

The arguments (above) seem, perhaps, interesting, but there
are still, in this III millennium, many problems in defining
a more proper 'time', at the quantum level 
http://philsci-archive.pitt.edu/archive/00000368/
http://math.ucr.edu/home/baez/uncertainty.html
http://www.damtp.cam.ac.uk/user/jono/thesis.html
http://www.arxiv.org/abs/quant-ph/9906030
http://www.arxiv.org/abs/quant-ph/0110004
http://www.arxiv.org/abs/quant-ph/0211047
http://ilja-schmelzer.de/GET/timeIsham.html

"Another claim which frequently appears in the literature
is the following: If dt is the duration of the measurement
of an energy, the result is uncertain by DE >/= 1/2 hbar/dt.
This claim is absurd. It is analogous to saying that if we
measure a momentum with an apparatus of size dx, the momentum
uncertainty is Dp >/= 1/2 hbar/dx. This is manifestly wrong:
a mundane radio receiver whose size is only a few centimeters
can determine the wavelength of a radio station with an accuracy
Dlambda/lambda << 1. In other words, it measures the momentum
of the photons emitted by that station with an accuracy
            Dp << hbar/lambda << hbar/dx.
Still another claim [....] is that the time (registered by
a clock) at which an energy is measured with an accuracy
DE, is uncertain by at least hbar/DE. This already sounds
better, because we have defined a clock-time operator T_c,
and we can therefore investigate the possible existence of
an uncertainty relation between DT_c and DH. However there is
no reason to expect that there actually is such an uncertainty
relation, because the operator T_c refers to the clock, and
the operator H to the observed system. These two operators
commute, and quantum theory allows us, in principle, to
measure both of them simultaneously with arbitrary accuracy.
                      [short snip]
These issues were not understood in the early days of quantum
theory. It is only at much later stage that they were throughly
analyzed by Aharonov and Bohm, who came to the conclusion that
<there is no reason inherent in the principles of quantum theory
why the energy of a system cannot be measured in as short a time
as we please>." 

- Asher Peres, 'Quantum Theory: Concepts and Methods', Kluwer,
Academic P., 1998, page 414-etc.