Controlled Erasure as a Building Block for Universal Thermodynamically-Robust Dynamical Computing

Improving the energy efficiency of computing devices remains a fundamental engineering and social challenge of increasing importance. To help address this challenge, we extend an alternative computing paradigm which manipulates microstate distributions that reside in the metastable minima of a potential energy landscape. These minima serve as mesoscopic memory states, whose dynamic manipulation corresponds to information processing. Central to our results is the control erase (CE) protocol, which controls the landscape’s metastable memory states in order to selectively store or erase information. Importantly, successive CE executions can implement the NAND gate---a logically-irreversible universal logic gate. We show how to practically implement a NAND gate with a device created by two inductively-coupled superconducting quantum interference devices (SQUIDs). Using bifurcation theory, we identify circuit parameter ranges which give rise to CEs that are robust against logical errors. These SQUID-based devices are capable of operating above GHz frequencies and at the k_BT energy scale. Further optimized devices and protocols can provide a universal computing substrate that is both computationally fast and energy efficient.