C6 Hydrogen 21 cm Line

Edward Purcell and Norman Ramsey:
Cosmology and the Atomic Clock

Sculptures celebrating the research that used the 21 cm (1.420 405 751 GHz) hyperfine transition in atomic hydrogen:   Not only to study the distribution of matter in the universe but also to provide a highly precise standard of time.

In the n=1 state of atomic hydrogen, the electron spin may be aligned either parallel (F=1) or antiparallel (F=0) to the spin of the proton nucleus.  Transitions between these two hyperfine states occur at a well-defined microwave frequency.  The energy levels, and the manner in which they vary with the strength of an externally-applied magnetic field  are shown in the famous Breit-Rabi diagram:

Breit-Rabi diagram Bare

This suggests the form for a door pull:


which on double doors would be of the form:


and as seen from a distance (click on image for larger view):



Going further, one can easily argue that the  21 cm line of hydrogen warrants a prominent, outdoor sculpture as a reminder of its significance.  Here, with a figure to indicate human scale, is a maquette for such a sculpture.


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