<https://www.sciencedaily.com/releases/2024/04/240429103045.htm>

 The 'thorium transition', which has been sought after for 

On usenet, sci.electronics.design, there just develops a discussion on Thorium transitions that may be usable for clocks. I had not yet the time to delve into that. Unfortunately, s.e.d. has a bad S/N ratio. Too many trolls since not moderated. regards, Gerhard ----------------------------------------------------------------------- On 5/8/24 01:36, John Larkin wrote: > On Tue, 07 May 2024 12:17:24 -0400, Joe Gwinn <joegwinn@comcast.net> > wrote: > >> On Tue, 7 May 2024 16:26:27 +0200, Jeroen Belleman >> <jeroen@nospam.please> wrote: >> >>> On 5/7/24 15:35, Martin Brown wrote: >>>> On 07/05/2024 06:06, Jan Panteltje wrote: >>>>> Atomic nucleus excited with laser: a breakthrough after decades >>>>> <https://www.sciencedaily.com/releases/2024/04/240429103045.htm> >>>>> The 'thorium transition', which has been sought after for >>>>> decades, >>>>> has now been excited for the first time with lasers. >>>>> This paves the way for revolutionary high precision >>>>> technologies, >>>>> including nuclear clocks >>>> >>>> I wonder what the Q value for stimulated nuclear emission is? >>> They state a centre frequency of roughly 2 PHz and a decay time >>> of 630s, which would put the Q in the 1e19 ballpark. Prodigious. >>> No wonder it was hard to find. >> The Time guys have been looking for this forever, so to speak. >> It's the only atomic kernel transition with any degree of coupling to >> electromagnetic radiation. This will be orders of magnitude better >> than such as lattice clocks. >> >> There will be a flood of papers. >> JG > They aren't tuning to a resonance, but to the difference between two > close resonances. The current definition of the second uses something similar: Some hyperfine resonance of cesium. Normal resonances are in the optical domain, but hyperfine ones are RF. In nuclei, normal transitions are in the gamma domain, and hyperfine ones are in the domain of optics. It's just a change of scale, if you will. JB

Dear time nuts, On Wednesday, 8 May 2024 12:20:24 CEST Gerhard Hoffmann via time-nuts wrote: > On usenet, sci.electronics.design, > there just develops a discussion on Thorium transitions that may > be usable for clocks. > I had not yet the time to delve into that. > Unfortunately, s.e.d. has a bad S/N ratio. Too many trolls since not > moderated. There is a viewpoint on https://physics.aps.org/articles/v17/71 The Schumm and Peik groups worked together to narrow down the previously rather unknown transition frequency for the optical excitation of a Thorium nucleus by a factor of 800 to a few GHz uncertainty. Now the construction of narrow continuous wave 148 nm laser systems can begin and maybe soon the nuclear transition can be driven coherently. The original article is also freely accessible: https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.132.182501 Cheers, Jürgen