Studying Quantum Mechanics in the Time Domain

Hole dynamics and coherence

23 Aug 2011, 16:00

1h

FR4, Oskar Klein Auditorium

Speaker

Robin Santra (DESY Hamburg)

Description

Photoionization of an atom or a molecule leads, in general, to the formation of a superposition of ionic eigenstates. That superposition cannot, in general, be described in terms of a wave function, but a description in terms of a reduced density matrix (a statistical mixture) is required. In the first part of the talk, ultrafast, partially coherent hole dynamics driven by spin-orbit coupling will be analyzed in terms of a time-dependent multichannel mean-field theory [1]. This theory will be compared with the results of an attosecond transient absorption experiment on strong-field-ionized krypton atoms [2]. In the second part of the talk, a new implementation of time-dependent configuration interaction singles (TDCIS) will be discussed [3]. Using TDCIS calculations, it will be shown that photoelectron-mediated interchannel coupling causes ion decoherence in attosecond photoionization. As a consequence, even if the spectral bandwidth of the ionizing pulse exceeds the energy splittings among the hole states involved, perfectly coherent hole wave packets cannot be formed [4]

[1] N. Rohringer and R. Santra, Phys. Rev. A 79, 053402 (2009).
[2] E. Goulielmakis, Z.-H. Loh, A. Wirth, R. Santra, N. Rohringer, V. S. Yakovlev, S. Zherebtsov, T. Pfeifer, A. M. Azzeer, M. F. Kling, S. R. Leone, and F. Krausz, Nature 466, 739 (2010).
[3] L. Greenman, P. J. Ho, S. Pabst, E. Kamarchik, D. A. Mazziotti, and R. Santra, Phys. Rev. A 82, 023406 (2010).
[4] S. Pabst, L. Greenman, P. J. Ho, D. A. Mazziotti, and R. Santra, Phys. Rev. Lett. 106, 053003 (2011).