Path: ...!Xl.tags.giganews.com!local-2.nntp.ord.giganews.com!nntp.supernews.com!news.supernews.com.POSTED!not-for-mail NNTP-Posting-Date: Wed, 08 May 2024 14:29:27 +0000 From: John Larkin Newsgroups: sci.electronics.design Subject: Re: OT: Atomic nucleus excited with laser: a breakthrough after decades Date: Wed, 08 May 2024 07:27:42 -0700 Organization: Highland Tech Reply-To: xx@yy.com Message-ID: References: X-Newsreader: Forte Agent 3.1/32.783 MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit Lines: 70 X-Trace: sv3-lHQCGfl3vqjjFkGMUYHHCnwQC39/nNK9uc34qRqLc2drP7ieg3K2YZZd2U8hafw0tX8Z9leWX9l53uM!Cm+PNHf0og5lOXptlpbetGnGXZc3s0ihuUobRNP4qlDwaSCxvXLFuT5zJr/hEnXPs7cy8srWVtba!0HGuvw== X-Complaints-To: www.supernews.com/docs/abuse.html X-DMCA-Complaints-To: www.supernews.com/docs/dmca.html X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly X-Postfilter: 1.3.40 Bytes: 4160 On Wed, 8 May 2024 12:52:27 +0100, Martin Brown <'''newspam'''@nonad.co.uk> wrote: >On 08/05/2024 09:44, Jeroen Belleman wrote: >> On 5/8/24 01:36, John Larkin wrote: >>> On Tue, 07 May 2024 12:17:24 -0400, Joe Gwinn >>> wrote: >>> >>>> On Tue, 7 May 2024 16:26:27 +0200, Jeroen Belleman >>>> 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 >>>>>>>    >>>>>>>     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. >>>> >>>> Joe Gwinn >>> >>> 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. > >Which puts them in the RF frequency domain where counting cycles of the >continuous sine reference waveform is relatively easy. > >Likewise for H-maser another favourite local time reference signal. > >> 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. > >Although there will be some big practical difficulties counting cycles >of a waveform at 8eV which is up into the UV. What is the current >highest frequency that a semiconductor divider is capable of accepting? > >I know that there are some optical logic circuits about but how capable >are they at near UV light? > >You can't mix this thing down without losing its fidelity. I know how to >double optical frequencies but how do you halve or quarter them? I don't know if there is a way to divide a lightwave-sorts of frequency down into the electronic domain. Much less gamma ray frequencies. Even the small differences cited here are still optical.