Synopsis: Looking for a Dark Matter Signal in Atomic Spectra

Scientists have now enlisted atomic spectroscopy in the hunt for dark matter.
Synopsis figure
K. Van Tilburg et al., Phys. Rev. Lett. (2015)

Most terrestrial dark matter searches look for signatures of dark matter particles scattering off other particles. Researchers have now demonstrated a new search strategy that involves detecting variations in atomic spectra that would result from possible dark matter–photon interactions. A two-year study of a certain heavy atom’s spectrum found no such signal, allowing the team to set strict limits on very-low-mass dark matter particles.

Dark matter searches often focus on particles with masses in the 109 to 1011 eV/c2 range, but other well-motivated candidates, like axions and dilatons, weigh much less than 1 eV/c2. Some of these ultralight particles are predicted to have interactions with photons that would cause the fine-structure constant α to fluctuate with time. The effect would, however, only be significant if the dark matter particle has a mass less than about 10-15 eV/c2, which is a mass range that has only been partly constrained by equivalence principle tests and cosmological observations.

A team from Stanford University in California and the Helmholtz Institute Mainz in Germany has devised an experiment that could potentially detect a dark matter influence over α. For their study, they chose the rare-earth element dysprosium, which has a unique α sensitivity in one of its electronic transitions. If α were to increase, the energy of this transition would increase for one isotope of dysprosium (Dy-162), but for a different isotope (Dy-164) the transition energy would decrease. The researchers measured the transition in both isotopes, but they detected no fluctuations on various time scales. The null result places the tightest constraints so far on dark matter in the 10-18 to 10-24 eV/c2 range.

–Michael Schirber

This research is published in Physical Review Letters.


Features

More Features »

Announcements

More Announcements »

Subject Areas

Atomic and Molecular PhysicsCosmology

Previous Synopsis

Atomic and Molecular Physics

Mid-Infrared Lasers Probe Atomic Structure

Read More »

Next Synopsis

Related Articles

Viewpoint: Alkaline Atoms Held with Optical Tweezers
Quantum Information

Viewpoint: Alkaline Atoms Held with Optical Tweezers

Three separate groups demonstrate the trapping of two-electron atoms in arrays of optical tweezers, opening up new opportunities for quantum simulation and many-body studies. Read More »

Synopsis: Universe Preceded by an Antiuniverse?
Cosmology

Synopsis: Universe Preceded by an Antiuniverse?

A new cosmology model suggests that our Universe has a mirror image in the form of an “antiuniverse” that existed before the big bang. Read More »

Viewpoint: The Quest to Make a Ferromagnet with Cold Atoms
Magnetism

Viewpoint: The Quest to Make a Ferromagnet with Cold Atoms

Experimentalists working with cold atoms are closing in on the famous Stoner model of ferromagnetism. Read More »

More Articles