Loss of coherence in atomic ionization with attosecond pulses*

The ions that emerge from the ionization of an atomic target with short light pulses are only partly coherent, since the possible ionic states are entangled with different photoelectron wavepackets [1]. Here we use a newly developed ab initio program that solves the time-dependent Schroedinger equation for polyelectronic atoms, to study how the parameters of sequences of short ionizing pulses affect the residual ion coherence for helium and argon targets. The program originates from the merge between a time-dependent close-coupling code for two-active-electron atoms [2] and the Stock B-spline close-coupling structure program [3]. [1] S Pabst et al., Phys. Rev. Lett. 106, 053003 (2011). [2] L Argenti and E Lindroth, Phys. Rev. Lett. 105, 053002 (2010). [3] T Carette et al., Phys. Rev. A 87, 023420 (2013).