Progress towards Collective Quantum Effects Experiments on Trapped Neutral Atom Arrays

Collective quantum effects have been extensively researched since the pioneering work of Dicke. The rate of spontaneous emission can be either enhanced or suppressed through coherent interactions between quantum emitters. Collective constructive interference of emission is known as superradiance, while collective destructive interference is referred to as subradiance. These effects were previously thought to occur only in dense ensembles. However, our group has recently demonstrated that such collective behavior persists even in the dilute regime. In particular, recent work from our lab has experimentally shown that decay rates can be reduced by as much as 20 percent due to subradiance in a dilute atomic cloud with an optical depth of 10⁻² or lower. In related developments, An and colleagues predicted and experimentally demonstrated superabsorption, which can be viewed as the absorptive analog of superradiance. More recently, our lab reported the experimental observation of the absorptive analog of subradiance. Accurate simulation of these collective effects requires access to the full many body Hilbert space, which introduces a significant computational overhead. As a result, robust and reliable experimental platforms that effectively emulate the interactions of multiple quantum emitters are essential for understanding many quantum computing architectures. The primary goal of this work is to observe both superradiance and subradiance, along with their absorptive counterparts, in trapped atom arrays. Using a simple passive gold plated amplitude mask system illuminated by a multimode trapping laser, we form trapped atom (Rubidium-87) arrays with spacings ranging from 2 micrometers to 15 micrometers. We aim to systematically investigate how these collective quantum effects depend on array spacing, array geometry, loading rate, and temperature.