International Center for Quantum-field Measurement Systems for Studies of the Universe and Particle (WPI-QUP/KEK)
High Energy Accelerator Research Organization (KEK)
Kyoto University
Executive Summary
Question
The nature of invisible dark matter, constituting most of the matter in the Universe, remains one of the deepest mysteries in science. Quantum sensors, such as those based on nitrogen-vacancy (NV) centers in diamond, are emerging as powerful tools for detecting weak signals from ultralight dark matter like axions. However, existing strategies have not fully exploited the potential of diamond NV centers for fundamental physics.
Findings
The study demonstrates that the unique quantum properties of diamond NV centers can significantly improve sensing precision over conventional strategies in a realistic, noise-affected setting. In addition, a method that enhances response to dark matter induced signals with suppression of common environmental disturbances. Applied to axion dark matter searches, the approach can improve projected sensitivity to the axion-electron interaction by up to an order of magnitude relative to leading proposals.
Meaning
This work translates general principles of multilevel quantum metrology into a concrete powerful strategy for dark matter and fundamental physics searches. The method established in this work has broad potential applications beyond dark matter searches. It opens a promising direction for detecting exceptionally weak fundamental signals with higher dimensional quantum sensors.
Overview
Quantum sensors are emerging as powerful tools for detecting dark matter, whose nature remains unknown. In particular, diamond quantum sensors based on nitrogen-vacancy (NV) centers in diamond are considered a promising tool for detecting weak signals generated by light dark matter candidates such as axions. However, previous detection methods have not fully exploited the quantum-mechanical properties of NV centers.
In this study, it was shown that three-level qutrit systems realized in diamond NV centers can achieve higher measurement precision than conventional approaches. When applied to axion dark matter searches, this method can improve measurement precision and may enhance the sensitivity to axion–electron interactions by up to a factor of ten.
This work opens a new door for exploring extremely weak signals in fundamental physics using high-dimensional quantum sensors.
This study was published as a Letter in Physical Review A in June 2026.
Please refer to the press release for details.
Contacts
High Energy Accelerator Research Organization (KEK) Public Relations Office
e-mail: press@kek.jp