An optical second with lattice clocks

Rodolphe Le Targat, Chunyan Shi, Ulrich Eismann +10 more

Chunyan Shi, Ulrich Eismann, Jean-Luc Robyr +2 more

Qi Gao, Min Zhou, Chengyin Han +12 more

Abstract Optical clocks are the most precise measurement devices. Here we experimentally characterize one such clock based on the 1S0-3P0 transition of neutral 171Yb atoms confined in an optical lattice. Given that the systematic evaluation using an interleaved stabilization scheme is unable to avoid noise from the clock laser, synchronous comparisons against a second 171Yb lattice system were implemented to accelerate the evaluation. The fractional instability of one clock falls below 4 × 10−17 after an averaging over a time of 5,000 seconds. The systematic frequency shifts were corrected with a total uncertainty of 1.7 × 10−16. The lattice polarizability shift currently contributes the largest source. This work paves the way to measuring the absolute clock transition frequency relative to the primary Cs standard or against the International System of Units (SI) second.

Andrei Derevianko, Hidetoshi Katori

Recently invented and demonstrated optical lattice clocks hold great promise for improving the precision of modern time keeping. These clocks aim at the ${10}^{\ensuremath{-}18}$ fractional accuracy, which translates into a clock that would neither lose nor gain a fraction of a second over an estimated age of the Universe. In these clocks, millions of atoms are trapped and interrogated simultaneously, dramatically improving clock stability. Here the principles of operation of these clocks are discussed and, in particular, a novel concept of magic trapping of atoms in optical lattices. Recently proposed microwave lattice clocks are also highlights and several applications that employ the optical lattice clocks as a platform for precision measurements and quantum information processing.

P. Lemonde

Jérôme Lodewyck, Philip G. Westergaard, Arnaud Lecallier +2 more

In this paper, we review several aspects of the frequency stability of optical lattice clocks. We describe a new ultra-stable cavity design with reduced thermal noise and record frequency stability (below 10 −15 ), as well as a non-destructive detection scheme for measuring the clock transition probability. Given the experimental parameters we measured, we simulate different sequence strategies for optimizing the stability. Finally, we report on the development of a second optical lattice clock and simulate several comparison strategies. In particular, we show by a numerical method that a stability as low as 2 × 10 −16 τ −1/2 can be reached with optical lattice clocks, and we show how to demonstrate this stability with a double clock system.