AI Article Synopsis
- Time measurements have historically relied on the movements of particles and celestial bodies, with recent advancements in relativity and quantum mechanics allowing for precise definitions based on individual particles.
- A new clock design using an optical frequency comb and a Ramsey-Bordé atom interferometer enables synchronization to a specific frequency tied to a particle's mass, facilitating precise mass measurements.
- This method achieves an accuracy of 4 × 10(-9) for microscopic masses and helps redefine the kilogram based on modern scientific standards.
Article Abstract
Historically, time measurements have been based on oscillation frequencies in systems of particles, from the motion of celestial bodies to atomic transitions. Relativity and quantum mechanics show that even a single particle of mass m determines a Compton frequency ω(0) = mc(2)/[formula: see text] where c is the speed of light and [formula: see text] is Planck's constant h divided by 2π. A clock referenced to ω(0) would enable high-precision mass measurements and a fundamental definition of the second. We demonstrate such a clock using an optical frequency comb to self-reference a Ramsey-Bordé atom interferometer and synchronize an oscillator at a subharmonic of ω(0.) This directly demonstrates the connection between time and mass. It allows measurement of microscopic masses with 4 × 10(-9) accuracy in the proposed revision to SI units. Together with the Avogadro project, it yields calibrated kilograms.
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| http://dx.doi.org/10.1126/science.1230767 | DOI Listing |
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