Abstract
We study ultranarrow - transitions in Nd and Sm and demonstrate that they lie in the optical region. The transitions are insensitive to external perturbations. At the same time they are sensitive to the variation of the fine structure constant . The fractional accuracy of the frequency of the transitions can be smaller than , which may provide a basis for atomic clocks of superb accuracy. Sensitivity to the variation of approaches per year.
- Received 20 August 2012
DOI:https://doi.org/10.1103/PhysRevA.86.054502
©2012 American Physical Society