Hannover 2010 – scientific programme

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A: Fachverband Atomphysik

A 27: Ultra-Cold Atoms, Ions and BEC IV / Interaction with VUV and X-Ray Light II (with Q)

A 27.6: Talk

Friday, March 12, 2010, 15:15–15:30, F 303

Collectivity and interference in x-ray scattering on nuclei — •Adriana Pálffy, Christoph H. Keitel, and Jörg Evers — Max-Planck-Institut für Kernphysik, Heidelberg, Germany

Resonant scattering of monochromatized synchrotron radiation or light from upcoming x-ray laser sources can lead to coherent photo-excitation of nuclei. Such an excitation in a nuclear ensemble is of excitonic nature, and the underlying collective effects determine the coherent nuclear reemission in the forward direction or at the Bragg angle. The coherent decay of the collective nuclear excitation is considerably speeded up with respect to the incoherent decay channels and thus to the natural lifetime. It has been shown experimentally [1] that switching abruptly the direction of the magnetic hyperfine fields can control and even completely suppress the coherent decay channel due to destructive interference. With a proper choice of switching parameters, specific transitions between hyperfine levels can be restored thus controlling the polarization of the emitted x-ray light [2].

Based on the results of [1,2], we study here advanced coherent control schemes aimed at the selective population of nuclear states. We show that suppression of the coherent decay in resonant x-ray scattering can be used to control the effective branching ratio in nuclear systems, and thus the population of nuclear states. Prospects for the population of metastable nuclear states are discussed.

[1] Y. V. Shvyd’ko et al., Phys. Rev. Lett. 77, 3232 (1995)

[2] A. Pálffy, C. H. Keitel and J. Evers, Phys. Rev. Lett. 103, 017401 (2009)