Precision laser spectroscopy of a nuclear transition
Abstract
Precision measurements of the electronic degrees of freedom of trapped atoms have enabled breakthroughs such as the worldÕs most accurate atomic clocks [Phys. Rev. Lett. 123, 033201 (2019)] and tests of fundamental physics in the electromagnetic force sector and relativity. Precision measurements of the nuclear degrees of freedom could lead to further major breakthroughs, such as compact atomic clocks with significantly reduced environmental sensitivity, searches for time variation of the strengths of the strong force and the electromagnetic force with sensitivity improved by a factor of 105, searches for dark matter, and benchmarking of lattice QCD calculations. However, typical nuclear transitions have energies of 10 to 1000 keV which are inaccessible using precision laser spectroscopy techniques. There is only one known laser-accessible nuclear isomer transition, between the 5+/2 [633] ground and 3+/2 [631] metastable excited states of the thorium-229 nucleus, with a wavelength in the experimentally challenging VUV range of 149.7 ± 3.1 nm [Nature 573, 243 (2019)]. For 229Thn+ ions with n = 2 the lifetime of this transition is estimated to be between 103 and 104 s and the systematic frequency shifts can be well controlled [Phys. Rev. Lett. 108, 120802 (2012)], making this transition amenable to precision measurements with fractional uncertainty in the 10-19 range. The goal of this proposal is to perform two-photon electron bridge spectroscopy of the 229Th3+ nuclear isomer transition with a fractional uncertainty near 10-15. This is a stepping stone towards single photon nuclear spectroscopy with an ultimate fractional uncertainty of 10-19 or beyond.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Aug 31, 2020
- Source ID
- W911NF2010135
Entities
People
- David Leibrandt
Organizations
- Army Contracting Command
- United States Army
- University of Colorado Boulder