J = 0 metastable state of Th 2 + for a hyperfine-free nuclear clock
Year: 2026
Type: article
Abstract: We present measurements on a metastable state in Th 2 + with the electronic configuration 6 d 2 P 0 3 ( 5090 cm − 1 ) . This is motivated by the prospect of using the state in laser excitation of the low-energy Th 229 nuclear resonance independent from the leading hyperfine interactions. The 6 d 2 P 0 3 state has no dipole-allowed radiative decay channel and is connected to the second ground state 6 d 2 3 F 2 ( 63 cm − 1 ) through an electric quadrupole transition only. We populate the state by laser excitation at 484 nm via a higher excited level and detect its population in laser-induced fluorescence. The isotope shift of the J = 0 level between Th 2 + 232 and Th 2 + 229 is determined as a measure of the interaction of electronic and nuclear charge distributions. The lifetime of the level in our ion trap with buffer gas is limited by collisional mixing with the nearby state 5 f 6 d G 3 3 ( 5060 cm − 1 ) . In ultrahigh vacuum, it could serve as a hyperfine-free nuclear clock that is largely immune to field-induced frequency shifts via the electron shell.
Source: Physical Review A
DOI: 10.1103/c98g-6f84
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $2,675
OpenAlex ID: W7160876730