Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Physical Review Letters

Measurement and Cancellation of the Cold Collision Frequency Shift in an 87Rb Fountain Clock

Chad Fertig, Kurt Gibble

Published Aug 21, 2000• 135 citations
Publisher

Abstract

We measure a cold collision frequency shift in an ${}^{87}\mathrm{Rb}$ fountain clock that is fractionally 30 times smaller than that for Cs. The shift is $\ensuremath{-}0.38(8)\mathrm{mHz}$ for a density of $1.0(6)\ifmmode\times\else\texttimes\fi{}{10}^{9}{\mathrm{cm}}^{\ensuremath{-}3}$. We study the cavity pulling of the atomic transition and use it to cancel the cold collision shift. We also measure the partial frequency shifts of each clock state finding $2({\ensuremath{\lambda}}_{10}\ensuremath{-}{\ensuremath{\lambda}}_{20})/({\ensuremath{\lambda}}_{10}+{\ensuremath{\lambda}}_{20})\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0.1(6)$.

DOI
10.1103/physrevlett.85.1622

Related papers

Juggling atomic clocks

Chad Fertig, Kurt Gibble

We demonstrate a prototype of a laser-cooled 87Rb fountain clock and measure the frequency shift due to cold collisions. The shift is 30 times smaller than that in a laser-cooled Cs clock. We observe a density dependent pulling by the microwave cavity and use it to cancel the collision shift. We have also demonstrated a juggling atomic fountain to study cold collisions and we discuss the importance ofjuggling for future fountain clocks.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Dec 15, 2000•0 citations

Laser-cooled Rb clock

Chad Fertig, Jérémie Bouttier, Kurt Gibble

We demonstrate a prototype of a laser-cooled /sup 87/Rb fountain clock and measure the frequency shift due to cold collisions. The shift is fractionally 30 times smaller than that in a laser-cooled Cs clock. We observe a density dependent pulling by the microwave cavity and use it to cancel the collision shift. We have also demonstrated a juggling atomic fountain to study cold collisions and we discuss the importance of juggling for future fountain clocks.

Joint Conference of the European Frequency and Time Forum and IEEE International Frequency Control Symposium (EFTF/IFCS)•Nov 8, 2002•8 citations

Eliminating cold-collision frequency shifts

Kurt Gibble, BOUDEWIJN J. VERHAAR

A technique to cancel the frequency shift due to cold collisions of laser-cooled atoms is proposed. Results for future clocks based on $^{135}\mathrm{Cs}$ and $^{137}\mathrm{Cs}$ are presented. We find a $^{137}\mathrm{Cs}$ fountain clock can be operated with no cold-collision shift by adjusting the population ratios in the fountain, and it may also be possible for $^{135}\mathrm{Cs}$. This technique can also be applied to other phase-sensitive measurements using cold atoms, including atom interferometers.

Physical Review A•Oct 1, 1995•57 citations

Laser-Cooled Rb Clock

Chad Fertig, Kurt Gibble

Abstract—We demonstrate a prototype of a laser-cooled 87Rb fountain clock. We report a preliminary measurement of the frequency shift due to cold collisions and find the shift to be at least a factor of ten less than that in a laser-cooled Cs clock. We also demonstrate the use of the ac Zeeman shift to measure the response of a microwave cavity. Finally, we have demonstrated a juggling atomic fountain and discuss the application of this technique to fountain and microgravity atomic clocks. Index Terms—Atomic clock, microwave resonators, microwave spectroscopy, rubidium materials/devices. I.

•Sep 8, 2016•1 citation

Laser-cooled Rb fountain clocks

Chad Fertig, Ronald Legere, Wenko Süptitz +1 more

We demonstrate a prototype of a laser-cooled /sup 87/Rb fountain clock and report a preliminary measurement of the frequency shift due to cold collisions. We find the shift to be much smaller than that in a laser-cooled Cs clock. We have recently demonstrated a juggling atomic fountain to study cold collisions. We discuss the importance of juggling for future fountain clocks and the problems and potential solutions.

Joint Conference of the European Frequency and Time Forum and IEEE International Frequency Control Symposium (EFTF/IFCS)•Jan 22, 2003•12 citations

ATOMIC CLOCKS AND COLD ATOM SCATTERING

Chad Fertig, Ronald Legere, J. IRFON REES +3 more

We demonstrate a Rb fountain clock which has a small cold collision shift that is cancelled by detuning the microwave cavity. To further enhance the stability and accuracy, we are currently developing a new state detection technique that directly measures population differences and are juggling atoms in the fountain. Fountain clocks also enable a novel quantum atom-optics precision scattering measurement.

Laser Spectroscopy•Jun 1, 2002•1 citation
We measure a cold collision frequency shift in an 87Rb{}^{87}\mathrm{Rb}87Rb fountain clock that is fractionally 30 times smaller than that for Cs. The shift is \ensuremath−0.38(8)mHz\ensuremath{-}0.38(8)\mathrm{mHz}\ensuremath−0.38(8)mHz for a density of 1.0(6)\ifmmode×\else\texttimes\fi109cm\ensuremath−31.0(6)\ifmmode\times\else\texttimes\fi{}{10}^{9}{\mathrm{cm}}^{\ensuremath{-}3}1.0(6)\ifmmode×\else\texttimes\fi109cm\ensuremath−3. We study the cavity pulling of the atomic transition and use it to cancel the cold collision shift. We also measure the partial frequency shifts of each clock state finding 2(\ensuremathλ10\ensuremath−\ensuremathλ20)/(\ensuremathλ10+\ensuremathλ20)=0.1(6)2({\ensuremath{\lambda}}_{10}\ensuremath{-}{\ensuremath{\lambda}}_{20})/({\ensuremath{\lambda}}_{10}+{\ensuremath{\lambda}}_{20})\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0.1(6)2(\ensuremathλ10​\ensuremath−\ensuremathλ20​)/(\ensuremathλ10​+\ensuremathλ20​)=0.1(6).
A technique to cancel the frequency shift due to cold collisions of laser-cooled atoms is proposed. Results for future clocks based on 135Cs^{135}\mathrm{Cs}135Cs and 137Cs^{137}\mathrm{Cs}137Cs are presented. We find a 137Cs^{137}\mathrm{Cs}137Cs fountain clock can be operated with no cold-collision shift by adjusting the population ratios in the fountain, and it may also be possible for 135Cs^{135}\mathrm{Cs}135Cs. This technique can also be applied to other phase-sensitive measurements using cold atoms, including atom interferometers.
Abstract—We demonstrate a prototype of a laser-cooled 87Rb fountain clock. We report a preliminary measurement of the frequency shift due to cold collisions and find the shift to be at least a factor of ten less than that in a laser-cooled Cs clock. We also demonstrate the use of the ac Zeeman shift to measure the response of a microwave cavity. Finally, we have demonstrated a juggling atomic fountain and discuss the application of this technique to fountain and microgravity atomic clocks. Index Terms—Atomic clock, microwave resonators, microwave spectroscopy, rubidium materials/devices. I.