Evaluation of the two-photon exchange diagrams for the (1s)22p3/2(1s)^2 2p_{3/2} electron configuration in Li-like ions

We present ab initio calculations of the complete gauge-invariant set of two-photon exchange graphs for the $(1s)^2 2p_{3/2}$ electron configuration in Li-like ions. These calculations are an important step towards the precise theoretical determination of the $2p_{3/2}$-$2s$ transition energy in the framework of QED.Comment: 17 pages, 6 figure

On the adjoint group of semiprime rings

An associative ring R, not necessarily with an identity, is called radical if it coincides with its Jacobson radical, which means that the set of all elements of R forms a group denoted by R° under the circle operation r o s=r+s+rs on R. It is proved that every soluble normal subgroup of the adjoint group R° of a semiprime radical ring R is contained in the centre of R