近物所报告：UNUSUAL RELATIVISTIC SYSTEMS
报告题目: UNUSUAL RELATIVISTIC SYSTEMS
报告人：Prof. Vladimir Karmanov
(Lebedev Physical Institute of Russian Academy of Sciences )
One of the benchmark models for interaction in nuclear physics and in the non-relativistic quantum mechanics at all, presented in all the textbooks, is the zero-range interaction. However, in the relativistic domain, this model was developed only very recently, when the relativistic light-front wave function for a three-body system with zero-range interaction and the corresponding Bethe-Salpeter amplitude were calculated. Comparison of the solutions in these two relativistic approaches with each other and with the nonrelativistic one is rather instructive. In particular, as known, the non-relativistic three-body system with the zero-range interaction does not exist (because of so called Thomas collapse). Whereas in the relativistic case, the repulsive relativistic effects overcome the Thomas attarction and the system with a finite binding energy survives.
We consider also some systems existing exclusively due to relativity. Schrodinger equation has no these solutions.
These "abnormal" solutions of the Bethe-Salpeter equation in the Coulombien field were found long ago. However they require very large charge and therefore they are hardly realized in nature. In contrast to the massless exchange, we study the more realistic case of massive exchange with the coupling constant which is typical for the strong interaction. In these "normal" conditions, we still find the "abnormal" solutions of the Bethe-Salpeter equation. They can manifest themselves in nature.