On April 22, 2026, Dr. Florian Meinert successfully completed his habilitation process with the venia legendi in physics. In his habilitation lecture ‘The search for a nuclear atomic clock' on February 4 he addressed the current state of research on nuclear clocks.
The development of optical atomic clocks has already brought time measurement to a high level of precision. But the next revolution could lie hidden within the atomic nucleus itself: nuclear clocks based on the isotope thorium-229. Since the discovery of its exceptionally low-energy nuclear transition in 1976 by physicists L. A. Kroger and C. W. Reich, researchers worldwide have been searching for ways to directly excite this quantum mechanical state using lasers and to use it as a novel type of clock. In 2016, a research team at Ludwig Maximilian University of Munich (LMU) provided the first direct experimental proof of the existence of this nuclear state. In 2024, research teams from the Vienna University of Technology (TU Wien), and the National Metrology Institute (Physikalisch-Technische Bundesanstalt PTB) succeeded for the first time in specifically exciting the nuclear transition with lasers and measuring it precisely.
The lecture focused on the question of why a nuclear clock could potentially far surpass classical atomic clocks: the atomic nucleus is much better shielded from external disturbances than the electron shell. As a result, the thorium clock promises unprecedented stability and accuracy—with potential applications in fundamental physics, the search for variations in physical constants, or dark matter, and future navigation and communication systems.
The lecture was met with great interest and was followed by a lively professional discussion. From now on, Florian Meinert will teach and conduct research at the institute as a private lecturer. Congratulations!