  The presence of loss mechanisms governed by empirical time-scales affect the
dynamics and spectra of systems in profound ways. However, incorporation of
these effects and their interaction with the thermal dissipative environments
interacting with the system prove to be challenging. We have recently developed
the path integral Lindblad dynamics (PILD) method to combine numerically
rigorous path integral simulations with Lindblad dynamics to account for such
empirical loss mechanisms. In this work, we utilize the PILD method to study
the absorption and circular dichroism spectra of chiral molecular aggregates
and excitonic polaritons. We demonstrate that the effect of loss on particular
states in both systems can differ not just on the basis of the symmetries of
the state but also on the basis of complicated "interactions" of the system and
the loss mechanism with the dissipative environments. We present probably the
first numerical exploration of the CD spectrum of chiral molecular aggregates
confined in a cavity. While the CD spectrum of just the excitonic aggregates
itself is not amenable to simplistic understanding like the exciton chirality
(EC) rule, the CD spectrum of polaritonic molecules is even more complex.
Additionally, the impact of empirical loss on the polaritonic CD spectrum seems
to be highly site-dependent. The impact of a lossy cavity is qualitatively
different from the impact of a molecule that leaks the excitation. We explore
some of those effects in depth leveraging the framework of path integral
Lindblad dynamics.
