Information propagated by longitudinal pulses near a van der Waals phase transition.

Longitudinal pulses that propagate in a medium near a van der Waals phase transition have a sigmoidal dependence on the strength of the stimulus arising from the phase structure. This response resembles the all-or-nothing property of action potentials, which raises the question if an acoustic system near a phase transition can be suitable for material-based neuromorphic computation. Herein, we investigate how information about the stimulus is stored within these pulses. We find that (1) the pulse propagates in parallel both digital and analog information about the stimulus amplitude; (2) the pulse encodes the type of stimulus, for instance, mechanical or thermal; and (3) a collision between two pulses stores information about both stimuli and may be used as a fading memory. Our results unravel a rich encoding of information in a phenomenon that is both common in a plethora of materials and mimics neuronal signaling. In addition, we show that these pulses carry more information than is typically considered by models of neural computation. Therefore, this phenomenon is an excellent candidate for in materio computation.