On Tue, 30 Mar 2021 08:15:30 +0000 "Poul-Henning Kamp" <p...@phk.freebsd.dk> wrote:
> In one of his lectures Feynmann mentions that the energy levels of > hydrogen have been calculated to 15 or 16 digits "from first > principles". > > As far as I can figure out, that must have happened in the 1970'ies, > which means it was probably done on one of Seymour Cray's designs. > > Hydrogen is obviously "the easy one", but even if the calculation > scales to the power of four on the number of particles in the atom, > we should still be well inside current super-computing capacities. > > Do you know if anybody has considered that as way to nail the frequencies ? The Hydrogen atom is much easier to calculate than any of the Hydrogen-like atoms that we use for atomic clocks these days. As far as I am aware of, the complexity of doing a full from first principles calculation of even Ca+ is beyond what current computers can do. So people are still using approximations to calculate the energy levels for these. Sorry, I can't point you at papers at the moment. I know I have them somewhere on my harddrive, but I cannot figure out where I put them. Attila Kinali -- The driving force behind research is the question: "Why?" There are things we don't understand and things we always wonder about. And that's why we do research. -- Kobayashi Makoto _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.