Quantum logic clock returns to top performance

ScienceDaily | 7/15/2019 | Staff
pixielilia (Posted by) Level 4
Physicists at the National Institute of Standards and Technology (NIST) have been quietly upgrading their quantum logic clock design for the past eight years, mainly to reduce errors from unwanted motion of the single aluminum ion (electrically charged atom) that provides the clock "ticks."

As described in Physical Review Letters, the quantum logic clock's systematic uncertainty (how closely the clock represents the ion's natural vibrations, or frequency) is 9.5×10−19, the best of any clock worldwide. This means the logic clock would now neither gain nor lose one second in 33 billion years, which is about two-and-a-half times the estimated age of the universe.

NIST - Clocks - Atoms - Lattices - Laser

In this metric, it now outpaces both NIST clocks using neutral atoms trapped in lattices of laser beams, the ytterbium lattice clock and the strontium lattice clock.

"The logic clock's performance is not surprising to me," project leader David Leibrandt said. "Ion clocks are naturally better isolated from the environment -- which is the source of inaccuracy for atomic clocks -- than lattice clocks are. It's important to distinguish between precision and stability on this point. People expect that lattice clocks should perform the best in stability, and they currently do. Our newest quantum logic clock is the world leader in precision but not stability."

Clock - Stability - Time - Measurement - Ion

The logic clock's stability (how long it takes to measure the time) is 1.2×10−15 for a 1-second measurement, which is near the best achieved by a single ion clock but about 10 times worse than both NIST lattice clocks.

The quantum logic clock got its nickname because it borrows logical decision-making techniques from experimental quantum computing. Aluminum is an exceptionally stable source of clock ticks, vibrating between two energy levels over a million billion times per second, but its properties are not easily manipulated or detected with lasers. So, logic operations with a partner magnesium ion are...
(Excerpt) Read more at: ScienceDaily
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