[extropy-chat] if you draw a circle ...

scerir scerir at libero.it
Mon Jan 29 21:06:05 UTC 2007


Buckminster Fuller (quoted by Natasha):
> If you draw a circle in the sand and study only what's inside the circle,
> then that is a closed-system perspective. If you study what is inside the
> circle and everything outside the circle, then that is an open system
> perspective.

This may also have a deeper meaning.
I remember that Alfred Wehrl ('General properties 
of entropy', Rev. Mod. Phys., 50, 221-260 (1978))
wrote several examples (not necessarily
quantum, also classical) in which the entropy 
of two correlated/entangled subsystems (ie one 
inside a circle, or a surface, and one outside)
is less (sometimes the entropy is even negative) 
than the entropy of the two separated subsystems 
(after the so called 'tracing out'). 







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