A Jaynes-Cummings-Fano Model for Autoionizing Polaritons

Intense laser pulses can couple resonances in the continuum, giving rise to a split pair of autoionizing polaritons whose lifetime can be extended as a result of interference between radiative and Auger decay channels. We present an extension of the Jaynes-Cummings model to autoionizing states which quantitatively reproduces this phenomenology and allows us to study how the dressing laser parameters can be tuned to control the ionization rate of the polariton multiplet. We illustrate the potential of this model to estimate the splitting and widths of the polaritonic features in the attosecond transient-absorption spectrum of the argon atom in the energy region close to the $3s^{-1}n\ell$ autoionizing states and compare the results with ab initio simulations of the spectrum in realistic experimental conditions.