On Wednesday, October 22, 2003, at 08:51 PM, Paul A. Bristow wrote:
>  I (and others) also expressed the prejudice that all are kept as their 
>  base
>  unit, now that 'everyone' is using at least 64-bit doubles in their 
>  calculations
>  (which is enough to keep everyone except the astronomers in the 
>  exponent range.
>  And the significand precision available (15-ish decimal digits) is 
>  ample for all
>  physical measurements.

I want to disagree here. I know particle physicists who use singe 
precision (float) numbers in some of their calculations. If instead of 
a common choice of units where hbar=1 one uses SI unites, where hbar is 
about about 1e-34, there will be problems. Even worse problems come 
when hbar^2 is needed.

Since for many calculations I do in quantum mechanics a natural set of 
units is where hbar, the speed of light, and the charge of the electron 
are set to one, I would not like to be forced to use SI units.

Matthias

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