Date of Award

Spring 1-1-2015

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Physics

First Advisor

Jun Ye

Second Advisor

Deborah Jin

Third Advisor

Eric Cornell

Fourth Advisor

Ana Maria Rey

Fifth Advisor

Andrew Hamilton

Abstract

The pursuit of better atomic clocks has advanced many fields of research, providing better quantum state control, new insights in quantum science, tighter limits on fundamental constant variation, and improved tests of relativity. This thesis describes the construction and characterization of an 87Sr optical lattice clock with a state-of-the-art stable laser. The performance of an atomic clock is typically gauged by two figures of merit: stability and total systematic uncertainty. Stability is the statistical precision of a clock or frequency standard, and the total systematic uncertainty is the combined uncertainty of all known systematic measurement biases. Several demonstrations of clock stability are presented in this work, one of which was the first to significantly outperform ion clocks. The most recent of these measurements resulted in fractional stability of 2.2×1016 at 1 s, which is the best reported to date. This stability is used for two systematic evaluations of our clock. The first full evaluation at 6.4 × 1018 total uncertainty took the record for best clock performance. The second evaluation used improved strategies for systematic measurements, achieving a new best total systematic uncertainty of 2.1 × 1018. Using a combination of accurate radiation thermometry and temperature stabilization of the measurement environment, we demonstrate the first lattice clock to achieve the longstanding goal of 1018 level uncertainty in the formidable blackbody radiation shift. Improvements in the density, lattice ac Stark, and dc Stark shifts were also a result of innovations that are described in this thesis. Due to the low total uncertainty of the Sr clock, timekeeping based on this system would not lose a second in 15 billion years (longer than the age of the Universe), and it would be sensitive to a gravitational redshift corresponding to a height change of 2 cm above the Earth’s surface.

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Physics Commons

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