Limits on Fundamental Limits to Computation

TL;DR

This paper reviews fundamental physical and practical limits to computation, discussing how these constraints impact hardware scaling, energy efficiency, and algorithmic development, and explores potential ways to circumvent or understand these limits.

Contribution

It provides a comprehensive analysis of the fundamental and practical limits to computation, including manufacturing, energy, space, and design, and discusses implications for future technological progress.

Findings

Some limits have been circumvented through innovative techniques.

Engineering challenges may reveal previously unknown fundamental limits.

Understanding these limits is crucial for guiding future computing technology.

Abstract

An indispensable part of our lives, computing has also become essential to industries and governments. Steady improvements in computer hardware have been supported by periodic doubling of transistor densities in integrated circuits over the last fifty years. Such Moore scaling now requires increasingly heroic efforts, stimulating research in alternative hardware and stirring controversy. To help evaluate emerging technologies and enrich our understanding of integrated-circuit scaling, we review fundamental limits to computation: in manufacturing, energy, physical space, design and verification effort, and algorithms. To outline what is achievable in principle and in practice, we recall how some limits were circumvented, compare loose and tight limits. We also point out that engineering difficulties encountered by emerging technologies may indicate yet-unknown limits.