Computing with Coupled Relaxation Oscillators

This chapter focuses on recent works in experimentally demonstrating tunable coupled relaxation oscillators, based on the phenomenon of insulator‐metal transition in vanadium dioxide (VO₂), as an efficient non‐Boolean computational primitive capable of performing the visual saliency task. The chapter exploits the phase synchronization dynamics of pairs of coupled oscillators to compute a fractional distance norm that is suitable for associative computing. Complementary metal‐oxide‐semiconductor (CMOS) transistors supporting the Boolean computational framework have been the backbone of modern computation, and have fueled the information technology revolution for the past four decades. Mathematically, the quantification of the degree of match between two quantities requires the calculation of a distance between two points that represents the two quantities in a high‐dimensional space. It turns out that the so‐called ‘Boolean bottleneck’ arises from the requirement of a significant number of power‐intensive multiply‐accumulate (MAC) operations involved in the calculation of the distance norm.