A time-delayed physical reservoir with various time constants

Physical reservoir computing has been attracting attention in recent years. However, it remains unclear how much nonlinearity is required in the physical dynamics to achieve a high computational performance. Therefore, we focused on a resistor-capacitor circuit, which exhibits simple transient characteristics, and investigated the performance required for a physical reservoir. As a result, the proposed reservoir shows a high performance for time series prediction tasks and can be used as a computational resource even without high nonlinearity in the physical dynamics. These results are expected to help establish design guidelines that support the hardware implementation of physical reservoirs.