Researchers create a quantum crystal that could sense dark matter

Physicists at the National Institute of Standards and Technology (NIST) have created a new quantum crystal they believe could be used to sense dark matter. Physicists created the crystal by entangling the mechanical motion and electronic properties of a small blue crystal. The entanglement gave the crystal a quantum edge for measuring electric fields with record sensitivity they believe could enhance our understanding of the universe.

The crystal they developed contains 150 beryllium ions trapped inside of a magnetic field. The ions self-arranged into a flat 2D crystal that's only 200 millionths of a meter in diameter. Scientists on the project believe this type of quantum sensor has the potential to detect signals from dark matter.

Dark matter is an extremely important yet mysterious substance that scientists want to learn more about. Theories suggest dark matter could be subatomic particles that interact with normal matter through a weak electromagnetic field. Researchers believe their quantum crystal could move in the presence of dark matter by revealing collective changes among the spin of the ions in the crystal.

The vibrational excitation of the crystal can be measured by monitoring changes in the collective spin of those ions. Measuring spin indicates the extent of vibrational excitation, which is referred to as displacement. The sensor can measure external electric fields with the same vibration frequency with more than ten times the sensitivity of any previous atomic sensor.

During their experiments, the research team applied a weak electric field to the crystal to excite it during testing. Senior paper author John Bollinger said ion crystals could detect certain dark matter types such as axions and hidden photons interacting with normal matter via a weak electric field. Dark matter forms background signals with oscillation frequencies depending on the mass of the dark matter particle. In the last decade, researchers have searched for that type of dark matter using superconducting circuits. However, the motion of trapped ions provides sensitivity over a different range of frequencies.