[time-nuts] New atomic clock

[Michael Costolo]

I'll admit to being a bit rusty in my particle physics, but since when do neutrons orbit the nucleus? 

-Mike-



On Mar 13, 2012, at 5:04 PM, David McQuate <mcquate at sonic.net> wrote:

> The article was accepted for publication on Feb 22, 2012    in    Physical Review Letters.
> The March issue has already been published, so maybe this one will be in the April issue.
> 
> The title is
> Single-ion nuclear clock for metrology at the 19th decimal place
> 
> Authors:
> C. J. Campbell, A. G. Radnaev, A. Kuzmich, V. A. Dzuba, V. V. Flambaum, and A. Derevianko
> 
> If you Google the title, I think you'll be able to find a pdf at arxiv.org/pdf/1110.2490
> 
> The article discusses many factors necessary to obtain a fractional inaccuracy approaching 1e-19.
> The technique uses the 7.6 eV (ie 1.8377e15 Hz or 163 nm wavelength) nuclear magnetic-dipole
> transition in a single thorium 229  ion (3+).  This paper does not report experimental results--I don't
> think the scheme has yet been implemented.
> 
> "A pair of Th(3+) ions would be stored in a linear rf trap where strong rf confinement places both ions
> on the trap axis.  With a trap of radius 700 um, and drive frequency of 25 MHz..."
> 
> The 163nm interrogation light "might be generated by a multi-stage sum-frequency generation of
> visible or NIR light within nonlinear crystals...with the fundamental frequency locked to an ultra-stable
> optical resonator."
> 
> Laser cooling is used, using a 1088nm wavelength.  The same wavelength is used to suppress the
> Stark effect by three orders of magnitude.
> 
> Doppler shifts resulting from interrogation are reduced by alternating the direction of the probe beam.
> 
> A gravitational shift of 1e-19 will result from a difference in height of 1 mm.
> 
> A two week averaging time is suggested.
> 
> Dave
> wa8ywq
> 
> On 3/13/2012 11:37 AM, Joseph Gray wrote:
>> http://www.news.com.au/technology/sci-tech/nucelar-clock-100-times-more-accurate-than-atomic-clock/story-fn5fsgyc-1226297068083#ixzz1osFDYtyb
>> 
>> I didn't see a link to a more detailed article. This one tells you
>> almost nothing.
>> 
>> Joe Gray
>> W5JG
>> 
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