Re: [time-nuts] New atomic clock
If neutrinos can have mass, then I guess neutrons can have orbits. But what do I know? It's all Greek (letters) to me :-) Joe Gray W5JG > If you google "nuclear shell model" you'll find a good Wikipedia > article on the nuclear energy levels. Oddly enough, there is a similarity > between the electronic orbitals and nucleon wavefunctions so that neutron > "orbits" is not complete nonsense. > ___ > time-nuts mailing list -- time-nuts@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@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] New atomic clock
There's an interesting and more readable PRL by the same group, published last year on June 2 . Its on arXiv: 1110.2379v1 . or PRL 106, 223001 (2011). They have already built the trap and have laser-cooled the Thorium ions (cool pictures of the ion crystals). Their current problem is that the wavelength of the nuclear transition is not well known and its hard to build a UV laser when you don't know exactly where to tune it. Apparently the idea is due to a German physicist at the PTB named E. Peik. If you search arXiv under "peik" you'll find a bunch of other papers on the subject. If you google "nuclear shell model" you'll find a good Wikipedia article on the nuclear energy levels. Oddly enough, there is a similarity between the electronic orbitals and nucleon wavefunctions so that neutron "orbits" is not complete nonsense. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] New atomic clock
On 03/14/2012 12:53 AM, Michael Costolo wrote: I guess my point was the neutron is a nuclear particle and so the concept of it's orbit seemed, out of place. Hence my confusion. Excitation of neutron energy states might have been more appropriate language? Now where is my copy of Eisberg and Resnick? Orbit as such is a confusing term, only carried due to historic models, but it is handy reference to energy levels [1]. The neutron isn't neutral in this sense, it will follow the Pauli exclusion principle [2] just as the electrons and the protons. Interestingly enough, for an atom the Pauli exclusion principle, which prohibits two particles to have the same quantum state, acts independently on the electrons, protons and neutrons independently [3]. This is true for all fermions [4]. Alkali metals and selected ions all share the fact that they have a single electron in the outer "shell". Just as you select among atoms for single electrons, you could select for single protons or single neutrons. It's the same laws being applied all over again. It's all entangled in a strange but mostly consistent pattern which we know how it works to a very large degree, but really has no real understanding of why. The laws it obeys is obscure to say the least. Cheers, Magnus [1] http://en.wikipedia.org/wiki/Electron_shell [2] http://en.wikipedia.org/wiki/Pauli_exclusion_principle [3] http://en.wikipedia.org/wiki/Atomic_nucleus [4] http://en.wikipedia.org/wiki/Fermion -Mike- On Mar 13, 2012, at 7:45 PM, Magnus Danielson wrote: On 03/14/2012 12:27 AM, Michael Costolo wrote: I'll admit to being a bit rusty in my particle physics, but since when do neutrons orbit the nucleus? In the same way as the outer electron "orbits" the nucleus. It's a quantum state with energy levels. Select it wisely and it can provide a reference difference in energy. It's the same business as with any other atomic clock. Still, this is on the concept sketch state still. Lots of practicalities prior to put it into use. With a handful of these being investigated, the methods will develop and the bar for them will lower. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@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@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@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] New atomic clock
I guess my point was the neutron is a nuclear particle and so the concept of it's orbit seemed, out of place. Hence my confusion. Excitation of neutron energy states might have been more appropriate language? Now where is my copy of Eisberg and Resnick? -Mike- On Mar 13, 2012, at 7:45 PM, Magnus Danielson wrote: > On 03/14/2012 12:27 AM, Michael Costolo wrote: >> I'll admit to being a bit rusty in my particle physics, but since when do >> neutrons orbit the nucleus? > > In the same way as the outer electron "orbits" the nucleus. > > It's a quantum state with energy levels. Select it wisely and it can provide > a reference difference in energy. It's the same business as with any other > atomic clock. > > Still, this is on the concept sketch state still. Lots of practicalities > prior to put it into use. > > With a handful of these being investigated, the methods will develop and the > bar for them will lower. > > Cheers, > Magnus > > ___ > time-nuts mailing list -- time-nuts@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@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] New atomic clock
On 03/14/2012 12:27 AM, Michael Costolo wrote: I'll admit to being a bit rusty in my particle physics, but since when do neutrons orbit the nucleus? In the same way as the outer electron "orbits" the nucleus. It's a quantum state with energy levels. Select it wisely and it can provide a reference difference in energy. It's the same business as with any other atomic clock. Still, this is on the concept sketch state still. Lots of practicalities prior to put it into use. With a handful of these being investigated, the methods will develop and the bar for them will lower. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] New atomic clock
Thanks. I missed that discussion. Sometimes, when messages don't look immediately interesting, or when they stray way off topic, I'm prone to delete without reading :-) At times the list is very quiet and at other times too busy to keep up with. Joe Gray W5JG On Tue, Mar 13, 2012 at 1:27 PM, Attila Kinali wrote: > On Tue, 13 Mar 2012 12:37:02 -0600 > 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. > > See the thread starting at [1] and especially [2] for a "discussion". > > Attila Kinali > [1] http://www.febo.com/pipermail/time-nuts/2012-March/064837.html > [2] http://www.febo.com/pipermail/time-nuts/2012-March/064884.html > > -- > Why does it take years to find the answers to > the questions one should have asked long ago? > > ___ > time-nuts mailing list -- time-nuts@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@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] New atomic clock
Yes, I caught that, too. I just chalked it up to the average non-technical journalist, considering where this article was published. Joe Gray W5JG On Tue, Mar 13, 2012 at 5:27 PM, Michael Costolo wrote: > I'll admit to being a bit rusty in my particle physics, but since when do > neutrons orbit the nucleus? > > -Mike- ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] New atomic clock
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 wrote: > The article was accepted for publication on Feb 22, 2012inPhysical > 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 >> >> ___ >> time-nuts mailing list -- time-nuts@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@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@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] New atomic clock
The article was accepted for publication on Feb 22, 2012in 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 ___ time-nuts mailing list -- time-nuts@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@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] New atomic clock
On Tue, 13 Mar 2012 12:37:02 -0600 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. See the thread starting at [1] and especially [2] for a "discussion". Attila Kinali [1] http://www.febo.com/pipermail/time-nuts/2012-March/064837.html [2] http://www.febo.com/pipermail/time-nuts/2012-March/064884.html -- Why does it take years to find the answers to the questions one should have asked long ago? ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] New atomic clock
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 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
