Measuring Neutron Electric Dipole Moment at University of Illinois Urbana-Champaign

Monday - May 15 2023, 22:05 UTC - 1 year ago

The nuclear physics group at the University of Illinois Urbana-Champaign are looking for new physics evidence in neutrons. To do so, they are participating in the nEDM experiment which measures the neutron's electric dipole moment. A grant from the Department of Energy will fund the researchers to develop sensors based on nitrogen-vacancy diamond, to measure these subtle changes accurately. In addition, the material’s quantum properties make it a promising candidate for quantum sensing and quantum memory.

The University of Illinois Urbana-Champaign’s nuclear physics group is participating in the nEDM experiment at Oak Ridge National Laboratory.

Their aim is to measure the neutron’s electric dipole moment to constrain theories in particle physics.

This is the first time such an experiment has been attempted and could help in pushing the boundaries of knowledge in particle physics beyond the current standard model.

The team of researchers must construct sensors for the nEDM experiment to measure subtle changes in very strong electric fields. That's when Professor of Physics Douglas Beck and his research group stepped in.

They were recently awarded a grant from the Department of Energy to develop sensors based on nitrogen-vacancy diamond, a material whose quantum properties at low temperatures make it unusually sensitive to electric fields.

The unique quantum properties of nitrogen-vacancy diamond make it a promising candidate for quantum sensing and quantum memory.

Chemically added nitrogen vacancy (NV) impurities give diamond its unusual electric field sensitivity.

"These impurities are regions with an extra nitrogen atom and a hole [or vacancy] where carbon atoms normally would be." Beck said. "When the material is cooled to less than 20 degrees above absolute zero, the impurities form a quantum system that responds to electric fields." .

The NV system can be made even more sensitive when it is prepared in a particular quantum state.

Instead of letting the system stay in its lowest energy state after they cool it, the researchers form a quantum superposition of the lowest and next-lowest energy states called a dark state. This dark state is immune to interactions with the environment, allowing the researchers to measure small electric fields accurately.

The research team has demonstrated that this phenomenon enables NV diamond to measure strong electric fields.

The grant will now enable the researchers to develop reliable sensors based on the material. This will involve packaging the sensors into units that readily connect with the lasers used to control them.

In addition to the nEDM experiment, the research team is investigating potential applications of the material in quantum information science.

The unique quantum properties of nitrogen-vacancy diamond make it a promising candidate for quantum sensing and quantum memory.