Highly charged ions for atomic clocks, quantum information, and search for α variation.

We propose 10 highly charged ions as candidates for the development of next generation atomic clocks, quantum information, and search for α variation. They have long-lived metastable states with transition wavelengths to the ground state between 170-3000 nm, relatively simple electronic structure, stable isotopes, and high sensitivity to α variation (e.g.

Muon loop light-by-light contribution to hyperfine splitting in muonium.

Three-loop corrections to hyperfine splitting in muonium, generated by the gauge-invariant sets of diagrams with muon and tauon loop light-by-light scattering blocks, are calculated. These results complete calculations of all light-by-light scattering contributions to hyperfine splitting in muonium.

Abrikosov-Nielsen-Olesen string with non-Abelian moduli and spin-orbit interactions.

It is generally believed that the spontaneous breaking of the Poincaré group by flux tubes (strings) generates only two zero modes localized on the string and associated with the spontaneous breaking of translational invariance (the so-called Low-Manohar argument). Being perfectly true in many instances this argument is nevertheless nonuniversal and has to be amended in the case of order parameters carrying spatial indices. We show that under certain circumstances additional zero (or quasizero) modes can appear due to spin symmetry.