Descrizione del progetto
È quasi l’ora del primo orologio nucleare al torio
Il progetto ThoriumNuclearClock, finanziato dall’UE, farà da pioniere nello sviluppo del primo orologio nucleare, basato su una transizione energetica nel nucleo dell’isotopo del torio Torio-229. Ciò promette di superare la precisione dei migliori orologi atomici attuali (che utilizzano i cambiamenti nei livelli energetici di elettroni a guscio atomici) anche di un ordine di grandezza. Il progetto svilupperà tre prototipi di orologi nucleari al torio attraverso approcci complementari in ioni e solidi intrappolati e svilupperà laser nell’ultravioletto da vuoto per eccitare l’isotopo del torio. Mettendo a confronto questi orologi tra loro e con gli orologi ottici più all’avanguardia sarà possibile stabilire il nuovo standard di frequenza prima dell’applicazione definitiva per testare la fisica fondamentale.
Obiettivo
Th-229 has an exceptionally low-energy excited nuclear isomer state with an excitation energy of only a few electron volts, making it accessible to laser manipulation. With a predicted relative radiative linewidth of 1e-19, constructing a Thorium nuclear clock becomes possible that could rival todays most advanced optical atomic clocks.
The few-eV transition emerges from a fortunate near-degeneracy of the two lowest nuclear energy levels. However, the Coulomb and strong-force contributions to these level energies differ on the MeV level. This makes the Th-229 nuclear level structure uniquely sensitive to variations of fundamental constants and ultralight dark matter.
Very recently, the applicants have proven the long-sought existence of the low-energy isomer, determined the lifetime in different electronic environments, quantified the nuclear moments and charge radius based on the hyperfine splitting, and constrained the isomer energy. However, knowledge on the electronic and nuclear properties is still insufficient to exploit the Th-229 system for fundamental tests.
This project aims to close this gap and realize three prototype nuclear Thorium clocks using complementary approaches in trapped ions and solids. We will develop customized VUV laser systems and perform precision spectroscopy of the Th-229 nuclear transition. Comparing these clocks among each other and with state-of-the-art optical clocks will allow us to benchmark the new frequency standard before ultimately applying it to test fundamental physics.
This project requires a unique combination of experimental and theoretical expertise in atomic and nuclear physics, high precision metrology and fundamental symmetries. Furthermore, special infrastructure is required for (distributed) clock comparison, precision spectroscopy as well as processing of Th-229. The synergy team is composed to optimally respond to these challenges while being rooted in established and successful collaborations.
Campo scientifico
Programma(i)
Argomento(i)
Meccanismo di finanziamento
ERC-SyG - Synergy grantIstituzione ospitante
1040 Wien
Austria