The record of atomic clock frequency comparisons at NIST over the past half-decade provides one of the tightest constraints of any present-day temporal variations of the fundamental constants. Notably, the 6-year record of increasingly precise measurements of the absolute frequency of the Hg(+) single-ion optical clock (using the cesium primary frequency standard NIST-F1) constrains the temporal variation of the. ne structure constant a to less than 2 . 10(-16) yr(-1) and offers a Local Position Invariance test in the framework of General Relativity. The most recent measurement of the frequency ratio of the Al(+) and Hg+ optical clocks is reported with a fractional frequency uncertainty of +/- 5.2 . 10(-17). The record of such measurements over the last year sensitively tests for a temporal variation of a and constrains. (alpha) over dot/alpha = (-1.6 +/- 2.3) . 10(-17) yr(-1), consistent with zero.

Recent atomic clock comparisons at NIST / Lorini, Luca; N., Ashby; A., Brusch; S., Diddams; R., Drullinger; E., Eason; T., Fortier; P., Hastings; T., Heavner; D., Hume; W., Itano; S., Jefferts; N., Newbury; T., Parker; T., Rosenband; J., Stalnaker; W., Swann; D., Wineland; J., Bergquist. - In: THE EUROPEAN PHYSICAL JOURNAL. SPECIAL TOPICS. - ISSN 1951-6355. - 163:(2008), pp. 19-35. [10.1140/epjst/e2008-00807-7]

Recent atomic clock comparisons at NIST

LORINI, LUCA;
2008

Abstract

The record of atomic clock frequency comparisons at NIST over the past half-decade provides one of the tightest constraints of any present-day temporal variations of the fundamental constants. Notably, the 6-year record of increasingly precise measurements of the absolute frequency of the Hg(+) single-ion optical clock (using the cesium primary frequency standard NIST-F1) constrains the temporal variation of the. ne structure constant a to less than 2 . 10(-16) yr(-1) and offers a Local Position Invariance test in the framework of General Relativity. The most recent measurement of the frequency ratio of the Al(+) and Hg+ optical clocks is reported with a fractional frequency uncertainty of +/- 5.2 . 10(-17). The record of such measurements over the last year sensitively tests for a temporal variation of a and constrains. (alpha) over dot/alpha = (-1.6 +/- 2.3) . 10(-17) yr(-1), consistent with zero.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11696/33565
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