Hannover 2010 – scientific programme
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A: Fachverband Atomphysik
A 18: Precision Spectroscopy of Atoms and Ions II
A 18.2: Talk
Thursday, March 11, 2010, 10:45–11:00, F 107
Recent theoretical progress in studying the two–photon emission from heavy, few–electron ions — •Filippo Fratini1,2, Thorsten Jahrsetz2, Thomas Stöhlker1,2, Stephan Fritzsche1,3, and Andrey Surzhykov1,2 — 1GSI Helmotholtzzentrum für Schwerionenforschung, D-64291 Darmstadt, Germany — 2Physikalisches Institut, Universität Heidelberg, D-69120 Heidelberg, Germany — 3Department of Physical Sciences, P.O. Box 3000, Fin-90014 University of Oulu, Finland
In this presentation we review the recent theoretical progress in studying the two–photon decay of few–electron ions. Special emphasis is placed on the quantum and classical correlations between the emitted photons. We argue that these correlations are described most naturally within the framework of the second–order perturbation theory and the density matrix approach. The general properties of the two–photon (spin) density matrix will be discussed both, in the non–relativistic dipole and exact relativistic approximations. By using these approximations, detailed calculations are performed for the angular and polarization correlations in the 2s1/2→ 1s1/2 as well as 21S0→ 11S0, 23P0→11S0 and 23S1→ 11S0 transitions in hydrogen– and helium–like ions, correspondingly [1]. Based on the results of these calculations, we discuss the role of relativistic and many–body effects in the correlated two–photon emission from heavy atomic systems.
[1] Th. Jahrsetz et. al., poster, this conference.