The field-to-particle transition problem
  We formulate in an intuitive manner several conceptual aspects of the field-to-particle transition problem which intends to extract physical properties of elementary particles from specific field configurations. We discuss the possibility of using the conceptual basis of the holographic principle and the mathematical fundaments of nonlinear sigma models for the field-to-particle transition. It is shown that certain classical gravitational configurations in vacuum may contain physical parameters with discrete values, and that they behave under rotations as particle-like objects. 
Jeronimo Cortez, Leonardo Patino and Hernando Quevedo