A Clock Directly Linking Time, to a Particle's Mass.
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| Title: | A Clock Directly Linking Time, to a Particle's Mass. |
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| Authors: | Shau-Yu Lan, Pei-Chen Kuan, Estey, Brian, English, Damon, Brown, Justin M., Hohensee, Michael A., Müller, Holger |
| Source: | Science (pre-March 2025). 2/1/2013, Vol. 339 Issue 6119, p554-557. 4p. |
| Subjects: | Time measurements, Particles, Mass measurement, Atomic clocks, Relativity (Physics), Atom interferometers, Avogadro's law, Wave packets, Optical frequency conversion, Quantum theory |
| 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 Campton frequency ω0 = mc²/ħ, where c is the speed of light and ħ is Planck's constant h divided by 2π. A clock referenced to ω0 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 ω0. This directly demonstrates the connection between time and mass. It allows measurement of microscopic masses with 4 x 10-9 accuracy in the proposed revision to SI units. Together with the Avogadro project, it yields calibrated kilograms. [ABSTRACT FROM AUTHOR] |
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| Database: | Psychology and Behavioral Sciences Collection |
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