[time-nuts] New atomic clock
michael.costolo at gmail.com
Tue Mar 13 23:27:33 UTC 2012
I'll admit to being a bit rusty in my particle physics, but since when do neutrons orbit the nucleus?
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
> 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.
> On 3/13/2012 11:37 AM, Joseph Gray wrote:
>> I didn't see a link to a more detailed article. This one tells you
>> almost nothing.
>> Joe Gray
>> time-nuts mailing list -- time-nuts at febo.com
>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
More information about the time-nuts