Eur. Phys. J. D 32, 39-43 (2005)
https://doi.org/10.1140/epjd/e2004-00182-3

Characterization of atomic avoided crossings by means of Fisher's information

¹ Theoretische Chemie, Physikalisch-Chemisches Institut, Im Neuenheimer Feld 229, 69120 Heidelberg, Germany
² Instituto `Carlos I' de Física Teórica y Computacional and Departamento de Física Moderna, Universidad de Granada, 18071 Granada, Spain

Corresponding author: ^a rosario@tc.pci.uni-heidelberg.de

Received: 14 June 2004
Revised: 14 October 2004
Published online: 7 December 2004

Abstract

Atomic avoided crossings in strong magnetic and electric fields are usually identified by the energy level repulsion and by the sharp extremal value of the Shannon's entropy of the two involved states. In this work the proposal of a new information-theoretic parameter, the continuous Fisher information, for the prediction and characterization of these nonlinear phenomena is done. For just around the irregular region it is found that Fisher's informations of the two states cross over and show that the states exchange their informational character. Moreover, the state Fisher information sum keeps constant through the avoided crossing. This is illustrated for some hydrogenic excited states in strong magnetic fields as well as in parallel magnetic and electric fields.