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Cancellation of the Collisional Frequency Shift in Caesium Fountain Clocks



K Szymaniec, W Chalupczak, Eite Tiesinga, Carl J. Williams, S Weyers, R. Wynands


We have observed that the collisional frequency shift in primary caesium fountain clocks varies with the clock state population composition and, in particular, is zero for a given fraction of the |F = 4, mF = 0> atoms, depending on the initial cloud parameters. We present a theoretical model explaining our observations. The possibility of the collisional shift cancellation implies an improvement in the performance of caesium fountain standards and a simplification in their operation. Our results also have implications for test operation of fountains at multiple pi/2 pulse areas.
Physical Review Letters


atomic clocks, ceasium, ultracold collisions


Szymaniec, K. , Chalupczak, W. , Tiesinga, E. , Williams, C. , Weyers, S. and Wynands, R. (2007), Cancellation of the Collisional Frequency Shift in Caesium Fountain Clocks, Physical Review Letters (Accessed July 17, 2024)


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Created April 12, 2007, Updated October 12, 2021