Search for Ultralight Dark Matter from Long-Term Frequency Comparisons of Optical and Microwave Atomic Clocks

We search for ultralight scalar dark matter candidates that induce oscillations of the fine structure constant, the electron and quark masses, and the quantum chromodynamics energy scale with frequency comparison data between a Yb-171 optical lattice clock and a Cs-133 fountain microwave clock that span 298 days with an uptime of 15.4%. New limits on the couplings of the scalar dark matter to electrons and gluons in the mass range from 10(-22) to 10(-20) eV/c(2) are set, assuming that each of these couplings is the dominant source of the modulation in the frequency ratio. The absolute frequency of the Yb-171 clock transition is also determined as 518 295 836 590 863.69(28) Hz, which is one of the important contributions toward a redefinition of the second in the International System of Units.

Automated summary

This study searches for ultralight scalar dark matter candidates and verifies the oscillation phenomenon of the fine structure constant, electron and quark masses, and quantum chromodynamics energy scale. New limits on the couplings of the scalar dark matter to electrons and gluons are also established.