Abstract:
The main question that has been answered in this research project is: what
happens to the singularities of the S-matrix when the interaction potential
becomes complex? In other words, we looked at the resonance spectral points
and traced their movements on the complex momentum plane, when the
imaginary part of the potential is gradually increased from zero to a certain
reasonable value. This question is important in many fields of research where
optical potentials are used. An optical potential can effectively take into
account the loss of the beam of particles into all the reaction channels that
are formally ignored. Such a simplified approach is widely used in nuclear
and atomic physics. In order to study the movement of the spectral points,
we used a simple potential and the Jost function method that allowed us to
easily locate the spectral points as complex zeros of the Jost function.
