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

Physics World

Juggling with time

Published Feb 1, 1999• 0 citations
Publisher

Abstract

The ability to juggle atoms may lead to a new breed of atomic clocks with unrivalled accuracy. By launching ultra-cold balls of caesium atoms in rapid succession, it should be possible to measure the frequency of atomic transitions with exceptional precision. Atomic transitions in caesium are currently used to define the fundamental unit of time and form the basis of atomic clocks, but existing caesium clocks use a beam of fast atoms emitted from an oven. While the clocks have an accuracy equivalent to one second in every 3 million years, atomic-clock experts believe that the precision has reached its limit.

DOI
10.1088/2058-7058/12/2/4

Related papers

Optical Lattice Clocks

Christopher W. Oates, Andrew D. Ludlow

A new breed of atomic clock—the “ticking” of which comes from transitions in millions of cooled atoms, trapped in optical standing waves created by tightly focused lasers—is pushing scientific timekeeping to previously unknown frontiers of precision.

Optics and Photonics News•Jan 1, 2015•1 citation

The Mercury Ion Optical Clock

Windell H. Oskay, Till Rosenband, U. Tanaka +5 more

The SI second is the most accurately realized of the base units, and time intervals can therefore be measured more precisely than any other fundamental quantity. Precision timing information from atomic clocks provides the backbone of such ubiquitous technologies as electrical power grids, wireless phone networks and the global positioning system. Today's best time and frequency standards, cesium fountain atomic clocks, have uncertainty at the level of about two nanoseconds per month. The search for yet more accurate and stable frequency standards has now led to the development of optical-frequency atomic clocks.

APS•May 1, 2004•0 citations

Laser-cooled Rb clocks and juggling atomic fountains

Kurt Gibble

Summary form only given. We juggle atoms in an atomic fountain by launching 2 balls of laser-cooled Cs atoms in rapid succession. The 2 balls collide near the top of the fountain and we detect the scattered atoms by measuring the changes in the atoms vertical velocity. Measuring the distribution of the velocity component along the collision axis gives the differential cross section. We scan the collision energy E/sub c/ by varying the time delay between launches and get the differential cross sections as a function of energy.

Quantum Electronics and Laser Science Conference•Jan 20, 2003•0 citations

Ultra-precise atomic clocks will redefine time

Physics Today•Sep 11, 2006•0 citations

Realization of advanced 171Yb optical lattice frequency standard

Gianmaria Milani

Atomic clocks constitute a fundamental tool for time and frequency metrology and their application is widespread in many technological fields. In particular, the International System of units (SI) defines the second on a microwave transition of Caesium atoms. The realization is made by clocks reaching uncertainties of few parts in 10^−16, making the second to be the quantity realized with the smallest uncertainty in the SI. However, a new generation of atomic clocks, called optical clocks, have already demonstrated to surpass Caesium standards both in accuracy and stability. The research performed during my PhD activity has been focused on the development and characterization of Ytterbium (Yb) optical lattice clocks. These systems operate with a large number of ultra-cold neutral atoms having a clock transition in the visible region of the electromagnetic spectrum. The atomic sample is trapped in an periodical optical potential called optical lattice that gives the advantage to interrogate many quantum absorbers for an extended time, with small perturbations, allowing to achieve an unprecedented stability and accuracy. The main experimental work has been carried out in the laboratories of the Istituto Nazionale di Ricerca Metrologica (INRIM) in Turin, where several atomic clocks are present including the Italian primary frequency standard, the Caesium fountain ITCsF2, and where an Yb optical lattice clock is currently being developed. This thesis describes the functioning of the system along with the full characterization of systematic effects, the complete uncertainty budget and its first absolute frequency measurement against the primary frequency standard. The clock exhibited an accuracy of 1.6 × 10^−16 and the comparison with the Cs fountain resulted in a frequency of f171Yb = 518 295 836 590 863.59(31) Hz, limited by the fountain uncertainty. This measurement is in agreement with the ytterbium frequency recommended as a secondary representation of the second in the SI and constitutes the first measurement of a Yb clock in Europe and the second one in the world against a primary frequency standard. Several upgrades have been applied after the absolute measurement. In particular, the design and realization a system capable to frequency stabilize several lasers on a single optical cavity is illustrated. This cavity has been implemented to lock the lasers used to cool and trap the atomic sample at 399, 556 and 759nm using the offset sideband locking technique, a modified version of the Pound–Drever–Hall method that gives an extended frequency tunability. The system proved to be an easy-to-use and reliable tool for the experimental activity showing a linewidth below 300 Hz at 556nm, which is the wavelength that requires the most stringent performance, and a long term drift below 20 kHz per day at 759nm. That is suitable for operating the lattice laser with a light shift uncertainty below 1 × 10−18. During my PhD I have been guest researcher at the National Institute of Standards and Technology (NIST) of Boulder, Colorado, for nine months in 2016. In these laboratories two Yb optical lattice clocks are operative. I worked on the instability measurement of a composite system exploiting the two clocks to suppress the Dick effect, called zero-dead-time (ZDT) clock, which demonstrated a fractional instability of 3 × 10−17 at 1s. The two clocks can also be operated to extend the interrogation time obtaining a spectroscopic feature after 4 s of 120(20)mHz corresponding to a quality factor Q > 4 × 10^15. I also worked on the characterization of several systematic shifts that allowed to complete the uncertainty budget of the clocks at 1.6 × 10^−18. In particular, I contributed to the characterization of lattice light shifts considering the effect of atomic sample temperature and the identification of a metrological regime called operational magic frequency where frequency shifts are insensitive to changes in trap depth.

•May 2, 2018•1 citation

Viewpoint: Keeping atoms synchronized for better timekeeping

Kurt Gibble

In a new regime for atomic clocks, strong interactions between atoms dramatically increase the clock’s coherence time.

•Jul 6, 2010•0 citations
The ability to juggle atoms may lead to a new breed of atomic clocks with unrivalled accuracy. By launching ultra-cold balls of caesium atoms in rapid succession, it should be possible to measure the frequency of atomic transitions with exceptional precision. Atomic transitions in caesium are currently used to define the fundamental unit of time and form the basis of atomic clocks, but existing caesium clocks use a beam of fast atoms emitted from an oven. While the clocks have an accuracy equivalent to one second in every 3 million years, atomic-clock experts believe that the precision has reached its limit.
The SI second is the most accurately realized of the base units, and time intervals can therefore be measured more precisely than any other fundamental quantity. Precision timing information from atomic clocks provides the backbone of such ubiquitous technologies as electrical power grids, wireless phone networks and the global positioning system. Today's best time and frequency standards, cesium fountain atomic clocks, have uncertainty at the level of about two nanoseconds per month. The search for yet more accurate and stable frequency standards has now led to the development of optical-frequency atomic clocks.
Summary form only given. We juggle atoms in an atomic fountain by launching 2 balls of laser-cooled Cs atoms in rapid succession. The 2 balls collide near the top of the fountain and we detect the scattered atoms by measuring the changes in the atoms vertical velocity. Measuring the distribution of the velocity component along the collision axis gives the differential cross section. We scan the collision energy E/sub c/ by varying the time delay between launches and get the differential cross sections as a function of energy.
Atomic clocks constitute a fundamental tool for time and frequency metrology and their application is widespread in many technological fields. In particular, the International System of units (SI) defines the second on a microwave transition of Caesium atoms. The realization is made by clocks reaching uncertainties of few parts in 10^−16, making the second to be the quantity realized with the smallest uncertainty in the SI. However, a new generation of atomic clocks, called optical clocks, have already demonstrated to surpass Caesium standards both in accuracy and stability. The research performed during my PhD activity has been focused on the development and characterization of Ytterbium (Yb) optical lattice clocks. These systems operate with a large number of ultra-cold neutral atoms having a clock transition in the visible region of the electromagnetic spectrum. The atomic sample is trapped in an periodical optical potential called optical lattice that gives the advantage to interrogate many quantum absorbers for an extended time, with small perturbations, allowing to achieve an unprecedented stability and accuracy. The main experimental work has been carried out in the laboratories of the Istituto Nazionale di Ricerca Metrologica (INRIM) in Turin, where several atomic clocks are present including the Italian primary frequency standard, the Caesium fountain ITCsF2, and where an Yb optical lattice clock is currently being developed. This thesis describes the functioning of the system along with the full characterization of systematic effects, the complete uncertainty budget and its first absolute frequency measurement against the primary frequency standard. The clock exhibited an accuracy of 1.6 × 10^−16 and the comparison with the Cs fountain resulted in a frequency of f171Yb = 518 295 836 590 863.59(31) Hz, limited by the fountain uncertainty. This measurement is in agreement with the ytterbium frequency recommended as a secondary representation of the second in the SI and constitutes the first measurement of a Yb clock in Europe and the second one in the world against a primary frequency standard. Several upgrades have been applied after the absolute measurement. In particular, the design and realization a system capable to frequency stabilize several lasers on a single optical cavity is illustrated. This cavity has been implemented to lock the lasers used to cool and trap the atomic sample at 399, 556 and 759nm using the offset sideband locking technique, a modified version of the Pound–Drever–Hall method that gives an extended frequency tunability. The system proved to be an easy-to-use and reliable tool for the experimental activity showing a linewidth below 300 Hz at 556nm, which is the wavelength that requires the most stringent performance, and a long term drift below 20 kHz per day at 759nm. That is suitable for operating the lattice laser with a light shift uncertainty below 1 × 10−18. During my PhD I have been guest researcher at the National Institute of Standards and Technology (NIST) of Boulder, Colorado, for nine months in 2016. In these laboratories two Yb optical lattice clocks are operative. I worked on the instability measurement of a composite system exploiting the two clocks to suppress the Dick effect, called zero-dead-time (ZDT) clock, which demonstrated a fractional instability of 3 × 10−17 at 1s. The two clocks can also be operated to extend the interrogation time obtaining a spectroscopic feature after 4 s of 120(20)mHz corresponding to a quality factor Q > 4 × 10^15. I also worked on the characterization of several systematic shifts that allowed to complete the uncertainty budget of the clocks at 1.6 × 10^−18. In particular, I contributed to the characterization of lattice light shifts considering the effect of atomic sample temperature and the identification of a metrological regime called operational magic frequency where frequency shifts are insensitive to changes in trap depth.