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PHYSICS NEWS UPDATE
The American Institute of Physics Bulletin of Physics News
Number 578 #2
February 27, 2002
By Phillip F. Schewe, Ben Stein, and James Riordon

Using Clocks in Space to Search for New Physics
Einstein's theory of relativity holds several things sacred. One is the idea that if you rotate a particle or object, or boost it up to a high velocity, the laws of physics affecting the object should stay the same. This is called Lorentz invariance.

But in some "extensions" of the standard model of particle physics, interactions of particles with certain hypothetical universal fields (very roughly analogous to the way in which Higgs bosons are supposed to make some particles massive) might lead to subtle violations of Lorentz invariance.

In a new paper Alan Kostelecky of Indiana University and his colleagues show how this can happen, and how such a violation could be detected in clock-comparison experiments now being readied for the International Space Station (ISS).

In general an atomic clock works by shooting microwaves into a sample of cooled cesium atoms and reading out the microwave-absorption frequency which corresponds to a specific quantum transition for electrons in the cesium atoms. The microwave frequency setting is used to define the "second."

If one can cool the atoms to lower temperatures (thus reducing the blurring caused by their movement) or observe them for longer periods, the precision of the whole readout process (and the standardization of the second) would improve.
(More: Physics News Update)
2002 © American Institute of Physics.

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