Improving Our Knowledge on the (229m)Thorium Isomer: Toward a Test Bench for Time Variations of Fundamental Constants

Thirolf, Peter G.; Seiferle, Benedict und Wense, Lars von der (2019): Improving Our Knowledge on the (229m)Thorium Isomer: Toward a Test Bench for Time Variations of Fundamental Constants. In: Annalen der Physik, Vol. 531, No. 5, 1800381

Abstract

For more than four decades, the lowest excitation in the whole landscape of atomic nuclei, the low-lying, isomeric state of Th-229, the so-called thorium isomer, has challenged physicists of various disciplines. Being a solitaire with its uniquely low excitation energy of <10 eV, its predicted lifetime of a few hours results in an extremely sharp relative linewidth Delta E/E as low as 10(-20). While until recently the indication of its existence was based only on indirect evidence, its unique properties inspired a multitude of potential applications, like the use of the thorium isomer as a nuclear frequency standard, potentially able to outperform even the best atomic clocks and a sensitivity-enhanced access to potential temporal variations of fundamental constants. The various proposals to exploit the unique properties of Th-229m are presented herein, in particular focusing on its ability to serve as a test bench for time variations of fundamental constants like the fine structure constant.

• Item Type: Journal article
• Faculties: Physics
• Subjects: 500 Science > 530 Physics
• ISSN: 0003-3804
• Language: English