Superradiant Peak Emission Rate and Time in Quantum Emitter Arrays

Determining the peak photon emission time and rate for an ensemble of $N$ quantum systems undergoing collective superradiant decay typically requires tracking the time evolution of the density operator. Generally, the dimension of the density operator grows exponentially ($\sim \! 2^N$) with the number of emitters, in the absence of any symmetries such as in Dicke superradiance with full or partial permutational symmetry. We present a detailed study of the superradiant peak emission rate and time for initially fully excited quantum emitter ensembles, for one-, two- and three-dimensional arrays in free-space and emitter chains coupled to waveguide reservoirs. For few emitters ($N\lesssim 14$) we utilize the full quantum master equation, and for mesoscopic emitter numbers ($N\lesssim 400$) we use a second- and third-order cumulant expansion of the operator averages to track the time evolution of the system.