Towards polariton neuromorphic engineering
The ubiquity of nonlinear oscillatory motion is perhaps best demonstrated with a pendulum which is harmonic only at small angles. Just as the harmonic oscillator provides a natural description of bosons in a quantum field, the Stuart-Landau oscillator provides a universal description of nonlinear oscillators close to a Hopf bifurcation. In the case of coupled nonlinear oscillators, time-delayed interactions increase the complexity of many physical systems ranging from coupled lasers, epidemiology, predator-prey, and road traffic systems to neuronal networks. Here, we explore the phase-space of ballistically coupled polariton condensates and demonstrate that the dynamics of the system are driven by the Lang-Kobayashi equation, and in the limit of fast relaxation of the exciton-reservoir feeding the condensates they can be described by time-delayed coupled Stuart-Landau oscillators. The controllability, complexity and similarity of ballistically coupled polariton condensates to many physical interacting systems establishes a strong motivation to apply polaritonics towards continuous recurrent artificial neural networks and is the first step forward in realizing integrated time delayed polariton networks for high speed optical neuromorphic computation.