Quantum Physics: How Quantum Crystals from NIST Could Be Used as Dark Matter Sensor

Physicists from the National Institute of Standards and Technology have successfully entangled mechanical motions with the electronic properties of a small blue crystal, thereby giving it a quantum edge capable of measuring electric fields and record sensitivity. This development can further our understanding of the universe.

Quantum Sensors

The developed quantum sensors are composed of 150 beryllium ions confined in a magnetic field for the ions to arrange themselves into a flat 2D crystal measuring at 200 millionths of a meter in diameter Phys.Org reports.

Quantum sensors have a remarkable potential to detect signals emanated by dark matter. For generations, astronomers and researchers have been puzzled by the theory of dark matter. Despite not being proven or measured to date, the mysterious substance might turn out to be, as some theories suggest, subatomic particles interacting with normal matter via weak electromagnetic fields, according to NASA.

Theoretically, the presence of dark matter would cause the quantum sensor crystals to wiggle in telltale ways. This is revealed by collective changes in the crystal's ions in one of their quantum properties known as spins.

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Dark Matter and Quantum Sensors

In the study published in the journal Science, titled "Quantum-Enhanced Sensing of Displacements and Electric Fields with Two-Dimensional Trapped-Ion Crystals," researchers were able to measure the vibrationally excited states of the crystal with the flat 2D plane moving up and down. This was made possible by closely monitoring the collective spin changes of the ions. Measuring the spin shows the excitation of vibrations known as displacement.

Researchers say that the sensors are able to measure the external electric fields, which are similar to the frequency of vibration of the crystals with a roughly ten times sensitivity from any previously demonstrated atomic sensors. In the experiments conducted, the researchers applied a weak electric field to test and excite the crystal sensors. A dark matter search would be relying on the same type of signal emission.

John Bollinger, NIST senior author, said that the ion crystals were able to detect specific types of dark matter such as axions and hidden photons interacting with normal matter via a weak electric field. He added that dark matter forms a subtle background signal with oscillating frequencies depending on the mass of the particle. Experiments conducted to search for this type of dark matter have been constantly undertaken for decades using superconducting circuits. The motion of these trapped ions provided sensitivity over a range of various frequencies.

In the future, researchers hope that increasing the number of ions in the crystals to roughly 100,000 via 3D crystals would improve the quantum sensors' capabilities by up to 30 times. Additionally, the stability of the crystals during their exciting motion would be improved. It may also enhance the time-reversal process required for achieving precise results.

The team says that they were able to improve the aspect of the quantum sensors. The experiment can, in time, become a fundamental resource for finally detecting and measuring dark matter.