Arxiv - A Single-Ion Nuclear Clock for Metrology at the 19th Decimal Place (5 pages)
This work has shown that the usual sources of clock shifts are suppressed in the proposed system, so that clock operation with inaccuracy approaching 1X10^-19 appears viable. With a more aggressive pursuit of systematic shift compensation and suppression, this value may very well be lowered to the 10^-20 scale, however, other systematic clock shift mechanisms may become operational at this level.
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