Advanced Atomic Clock Makes a Better Dark Matter Detector

Advanced Atomic Clock Makes a Better Dark Matter Detector

Credit: N. Hanacek/NIST



JILA researchers have used a state-of-the-art atomic clock to narrow the search for elusive dark matter, an example of how continual improvements in clocks have value beyond timekeeping.


Older atomic clocks operating at microwave frequencies have hunted for dark matter before, but this is the first time a newer clock, operating at higher optical frequencies, and an ultra-stable oscillator to ensure steady light waves have been harnessed to set more precise bounds on the search. The research is described in Physical Review Letters.


Astrophysical observations show that dark matter makes up most of the “stuff” in the universe, but so far it has eluded capture. Researchers around the world have been looking for it in various forms. The JILA team focused on ultralight dark matter, which in theory has a teeny mass (much less than a single electron) and a humongous wavelength — how far a particle spreads in space — that could be as large as the size of dwarf galaxies. This type of dark matter would be bound by gravity to galaxies and thus to ordinary matter.


Ultralight dark matter is expected to create tiny fluctuations in two fundamental physical “constants”: the electron’s mass, and the fine-structure constant. The JILA team used a strontium lattice clock and a hydrogen maser (a microwave version of a laser) to compare their well-known optical and microwave frequencies, respectively, to the frequency of light resonating in an ultra-stable cavity made from a single crystal of pure silicon. The resulting frequency ratios are sensitive to variations over time in both constants. The relative f ..

Support the originator by clicking the read the rest link below.