Optimal control of bit erasure in stochastic random access memory

TL;DR

This paper investigates the thermodynamic costs of bit erasure in CMOS-based RAM types, revealing optimal operating regimes and proposing a robust optimization scheme for energy-efficient memory operation.

Contribution

It introduces a framework for minimizing energy dissipation during bit erasure in realistic, non-equilibrium physical memory systems using mean field theory and automatic differentiation.

Findings

Dynamic RAM dissipates least energy in quasistatic limit with minimal errors.

Static RAM is most efficient in finite time due to energy to maintain bit state.

Proposed optimization scheme aligns with electrical engineering principles.

Abstract

Energy costs of information processing are growing exponentially. Bit erasure is a key problem in this energy-information nexus, and a number of seminal relationships have been deduced regarding the relationship between thermodynamic costs and memory storage. To continue making progress in the modern era, however, requires confronting thermodynamic costs in realistic physical systems which operate away from equilibrium. Here, we explore the thermodynamic costs of bit erasure in a complementary metal oxide semiconductor model of two types of random access memory. We find dynamic random access memory dissipates the least amount of energy when operated in the quasistatic limit, where errors are also minimized. By contrast, static random access memory is most efficiently operated in finite time due to the energy required to maintain the state of the bit. We demonstrate a numerically robust optimization scheme using mean field theory and automatic differentiation, finding optimal protocols compatible with electrical engineering insights. These results provide a framework for operating realistic circuits in thermodynamically advantageous ways.