New limits on variation of the fine-structure constant using atomic dysprosium

Understand

We report on the spectroscopy of radio-frequency transitions between nearly-degenerate, opposite-parity excited states in atomic dysprosium (Dy).

• Theoretical calculations predict that these states are very sensitive to variation of the fine-structure constant, $\alpha$, owing to large relativistic corrections of opposite sign for the opposite-parity levels.
• The near degeneracy reduces the relative precision necessary to place constraints on variation of $\alpha$ competitive with results obtained from the best atomic clocks in the world.
• Additionally, the existence of several abundant isotopes of Dy allows isotopic comparisons that suppress common-mode systematic errors.