There are many ways in which to evaluate the exact (or approximately exact) dynamics of a quantum mechanical system in addition to the one outlined above, which may be one of the simplest to write down. However, other approaches exist, such as the Multi-configuration time-dependent Hartree (MCTDH), 118;119;120;60;121 , the exact factorization (XF) , the hierarchical equation of motion (HEOM) 123;124 , etc., which have been already used for exploration in polaritonic systems. Additionally, ab initio multiple spawning (AIMS), 125;126 Ehrenfest multiple cloning (EMC), 127;69 and their variants 128;129;130 could also be adapted for polaritonic dynamics to give nearly exact results.