Instantaneous ionization rate as a functional derivative
Abstract
We describe an approach defining instantaneous ionization rate (IIR) as a functional derivative of the total ionization probability. The definition is based on physical quantities which are directly measurable, such as the total ionization probability and the waveform of the pulse. The definition is, therefore, unambiguous and does not suffer from gauge non-invariance. We compute IIR by solving numerically the time-dependent Schrodinger equation for the hydrogen atom in a strong laser field. We find that the IIR lags behind the electric field, but this lag is entirely due to the long tail effect of the Coulomb field. In agreement with the previous results using attoclock methodology, therefore, the IIR we define does not show measurable delay in strong field tunnel ionization.
Cite
@article{arxiv.1804.06556,
title = {Instantaneous ionization rate as a functional derivative},
author = {I. A. Ivanov and C. Hofmann and L. Ortmann and A. S. Landsman and Chang Hee Nam and Kyung Taec Kim},
journal= {arXiv preprint arXiv:1804.06556},
year = {2018}
}