Two–Loop Bethe Logarithms for Higher Excited S Levels

Calculation of Hydrogenic Bethe Logarithms for Rydberg States

We describe the calculation of hydrogenic (one-loop) Bethe logarithms for all states with principal quantum numbers n ≤ 200. While, in principle, the calculation of the Bethe logarithm is a rather easy computational problem involving only the nonrelativistic (Schrödinger) theory of the hydrogen atom, certain calculational difficulties affect highly excited states, and in particular states for w...

Discrete Levels Density and Spin Cut off Parameters of the 36Cl, 40K, 60Co and 61Ni Nucleuses

On the bases of Bethe and the constant temperature models, the level density parameters have been calculated for the 36Cl, 40K, 60Co and 61Ni nuclei, nucleuses through fitting the complete level schemes in low excitation energy levels. Both calculations reproduce experimental level densities equally well. Th...

Bethe logarithms for hydrogen up to n=20, and approximations for two-electron atoms.

Long - Range psu ( 2 , 2 | 4 ) Bethe Ansätze for Gauge Theory and Strings

We generalize various existing higher-loop Bethe ansätze for simple sectors of the integrable long-range dynamic spin chain describing planar N = 4 Super Yang-Mills Theory to the full psu(2, 2|4) symmetry and, asymptotically, to arbitrary loop order. We perform a large number of tests of our conjectured equations, such as internal consistency, comparison to direct three-loop diagonalization and...

Numerical Approach to Two-loop Three Point Functions with Masses

The calculation of loop integrals is essential to obtain the precise theoretical prediction for high-energy reactions. Loop integrals for oneloop diagrams can be expressed by logarithms and dilogarithms. For a class of higher order diagrams, compact analytic expressions are obtained. For instance, some two-loop two point functions with single mass(m) are given by functions of x = s/m. As two-lo...