Strong field physics in open quantum systems

Dephasing is the loss of phase coherence due to the interaction of an electron with the environment. The most common approach to model dephasing in light-matter interaction is the relaxation time approximation. Surprisingly, its use in intense laser physics results in a pronounced failure, because ionization {is highly overestimated.} Here, this shortcoming is corrected by developing a strong field model in which the many-body environment is represented by a heat bath. Our model reveals that ionization enhancement and suppression by several orders of magnitude are still possible, however only in more extreme parameter regimes. Our approach allows the integration of many-body physics into intense laser dynamics with minimal computational and mathematical complexity, thus facilitating the identification of novel effects in strong-field physics and attosecond {science}.