Experimental validation of binary collisions between wave fragments in the photosensitive Belousov–Zhabotinsky reaction

We present experimental verification of wave fragment collisions in the sub-excitable Belousov–Zhabotinsky medium observed previously in simulation [Adamatzky A, De Lacy Costello B. Binary collisions between wave fragments in a sub-excitable Belousov–Zhabotinsky medium. Chaos, Solitons & Fractals 2007;34:307–15]. We have reproduced in chemical experiments the majority of the collisions observed in simulation including annihilation, fusion and quasi-elastic types. The method we present is capable of implementing information transfer without any rigidly controlled architecture – fragments are simply introduced into an ‘‘arena” which consists of a large area of gel illuminated with a uniform light level – controlled at a level close to the sub-excitable threshold. Therefore, the fragments of excitation both pre and post collision possess a considerable freedom of movement when compared to previous implementations of information transfer in chemical systems. This chemical verification of previous theoretical results brings closer the possibility of utilising this phenomenon for implementing collision-based gates, signal tuning and programming of collision-based computers based upon excitable chemical reactions.