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PT4 - Variation of Fundamental Constants

Speaker

Leefer, Nathan

Coauthors

Leefer, Nathan; Van Tilburg, Ken; Bougas, Lykourgos; Budker, Dmitry

Talk Title

Tests of fundamental physics using atomic dysprosium

Abstract

Atomic dysprosium (Dy) is among the most complex atoms in terms of spectroscopy, and has proven to be a useful system for testing fundamental physics. In Dy, there is a pair of long-lived, excited non-Rydberg opposite-parity states that are separated in energy, depending on the isotope and hyperfine component, by anywhere between 3 MHz and a few GHz in the absence of external fields. The near degeneracy allows measuring the difference in the energies of the levels directly by radio-frequency (rf) spectroscopy, enabling sensitive exotic-physics searches with relaxed requirements for the rf source in terms of its fractional frequency stability. Over the years, Dy has been used to set stringent limits on physics beyond the standard model: a possible temporal variation of the fine-structure constant, α, variation in α induced by the changes of the gravitational potential of the Sun (exploiting the eccentricity of the Earth’s orbit), and certain types of violations of Lorentz invariance and the Einstein Equivalence Principle. Most recently, we have used Dy to constrain a model for ultralight dark matter with photon couplings across a wide range of masses.

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