A big spectrum of processes induced by real and virtual photons on the 3 He and 3 H nuclei is theoretically investigated through many examples based on nonrelativistic Faddeev calculations for bound and continuum states. The modern nucleon-nucleon potential AV18 together with the threenucleon force UrbanaIX is used. The single nucleon current is augmented by explicit π-and ρ-like two-body currents which fulfill the current continuity equation together with the corresponding parts of the AV18 potential. We also employ the Siegert theorem, which induces many-body contributions to the current operator. The interplay of these different dynamical ingredients in the various electromagnetic processes is studied and the theory is compared to the experimental data.Overall we find fair to good agreement but also cases of strong disagreement between theory and experiment, which calls for improved dynamics. In several cases we refer the reader to the work of other groups and compare their results with ours. In addition we list a number of predictions for observables in different processes which would challenge this dynamical scenario even more stringently and systematically.

This investigation presents an exactly solvable fractional model of linear viscoelastic behavior. In recent years both phenomenological-and molecular-based theories for the study of polymers and other viscoelastic materials came up with integral or differential equations of fractional order. Exact (analytical) solutions of such equations can be obtained by making use of the fractional calculus. Fox functions play a dominant part: they offer a wide spectrum of applications; however, they are applied little and they have not been used up to now within the context of viscoelasticity. A well-defined fractional initial value problem is derived by starting out with the Zener model. When the initial value problem is solved, a Fox function representation of the stress relaxation function is obtained. Further viscoelastic functions will be calculated analytically. Data sets of stress-strain experiments carried out on polyisobutylene and natural rubber are analyzed and compared with the predictions of the fractional theory. The agreement covers more than 10 orders of magnitude.

The pending question of the existence of three-neutron resonances near the physical energy region is reconsidered. Finite rank neutron-neutron forces are used in Faddeev equations, which are analytically continued into the unphysical energy sheet below the positive real energy axis. The trajectories of the three-neutron S-matrix poles in the states of total angular momenta and parity J π = 1 2 ± and J π = 3 2 ± are traced out as a function of artificial enhancement factors of the neutron-neutron forces. The final positions of the S-matrix poles removing the artificial factors are found in all cases to be far away from the positive real energy axis, which provides a strong indication for the nonexistence of nearby three-neutron resonances. The pole trajectories close to the threshold E = 0 are also predicted out of auxiliary generated three-neutron bound state energies using the Padé method and agree very well with the directly calculated ones.

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The asymptotic behavior of three-body scattering wave functions in configuration space is studied by considering a model equation that has the same asymptotic form as the Faddeev equations. Boundary conditions for the wave function are derived, and their validity is verified by numerical calculations. It is shown that these boundary conditions for the partial differential equation can be used to obtain accurate numerical solutions for the wave function.