[time-nuts] Exhaustive searches

[Lux, Jim]

On 2/18/21 7:40 AM, Poul-Henning Kamp wrote:
> --------
> Bob kb8tq writes:
>
>> Even if you went with a different material, moving any of the specs listed
>> above by 10X would be pretty amazing.
> That was the answer I expected :-)
>
> What about geometry ?
>
> Would things like whispering gallery improve things if we found a reasonable way to produce them ?
>
I think that hits the key... a 10 X improvement is unlikely. That's why 
everyone is looking at tiny atomic standards (like the CSAC or the 1 
liter Hg-ion aka DSAC).  Those get you (potentially) orders of magnitude 
improvement.

The DSAC is an interesting beast - today, it's pretty expensive 
(probably more than the notional $1M for a space USO), but potentially 
that could come down, because you're not trying to make the perfect 
crystal, in the perfect holder, in the perfect double dewar, with 
fraction of a gnat's eyelash temperature control.

There is *enormous* interest (and there has been for 100 years or more) 
in timekeeping (or other measurements) that are not affected by 
"manufacturing precision" or "assembly and calibration skill".