Actinide ions for testing the spatial α-variation hypothesis

الأصل · EN

Testing the spatial variation of fine-structure constant α indicated in [Webb et al., Phys. Rev. Lett. 107, 191101 (2011)] with terrestrial laboratory atomic measurements requires at least α/α 10⁻¹⁹ y⁻¹ sensitivity. We conduct a systematic search of atomic systems for such a test that have all features of the best optical clock transitions leading to possibility of the frequency measurements with fractional accuracy on the level of 10⁻¹⁸ or better and have a factor of 100 extra enhancement of α-variation in comparisons to experimental frequency ratio measurement accuracy. We identify the pair of actinide Cf¹⁵⁺ and Es¹⁶⁺ ions as the best system for a test of spatial α-variation hypothesis as it satisfies both of these requirements and have sufficiently simple electronic structure to allow for high-precision predictions of all atomic properties required for rapid experimental progress.