Highly charged ions for atomic clocks, cosmology, and quantum information
The past few years marked unprecedented improvements in both the accuracy and stability of optical frequency standards. With the current best clocks already approaching their predicted accuracy limits, what are the novel schemes for the next generation of clock development that may potentially achieve the accuracy at the next decimal point, 10-19? Further development of even more precise frequency standards is essential for new tests of fundamental physics, search for the variation of fundamental constants, very-long-baseline interferometry for telescope array synchronization, development of extremely sensitive quantum-based tools for geodesy, hydrology, and climate change studies, inertial navigation, and tracking of deep-space probes. If was recently shown that despite very large ionization energies, certain ions have transitions that lie in the optical range due to level crossings [PRL 105, 120801 (2011)]. Moreover, selected transitions in highly-charged ions were shown to have very large sensitivities to variation of the fine-structure constant which may approach per year. Some of these systems have several metastable states representing a level structure and other properties that are not present in any neutral and low-ionization state ions and may be advantageous for the development of atomic clocks as well as provide new possibilities for quantum information storage and processing. I will report results of our preliminary study of highly-charged ions that are particularly well suited for the experimental exploration for the applications listed above.