We can make atomic clocks even more accurate by just ignoring the atoms that 'die' the wrong way.
April 2, 2026
Original Paper
Extending the fundamental limit of atomic clock stability
arXiv · 2604.01099
The Takeaway
Standard models of timekeeping assume atoms only have two states, but real atoms are more complex. By detecting and 'throwing out' atoms that decay into the wrong energy levels, researchers pushed timekeeping precision nearly 5 decibels past what was previously thought to be an absolute physical wall.
From the abstract
Optical atomic clocks have been rapidly developing in recent decades, resulting in major improvements in both precision and accuracy. As a result, they have become instrumental in multiple areas of applied and fundamental research. Despite all atomic frequency references having more than two energy-levels, the commonly used model for evaluating their ultimate limits assumes a two-level atom. This leads to frequency interrogation protocols and theoretical stability bounds that are suboptimal for