The thermodynamic cost of quantum operations

TL;DR

This paper demonstrates that quantum computation inherently produces more heat than classical limits due to thermodynamic irreversibility, establishing a fundamental lower bound exceeding the Landauer Limit.

Contribution

It reveals an unavoidable excess heat generation in quantum computing, establishing a lower bound that surpasses the Landauer Limit and identifying conditions where this excess can be avoided.

Findings

Quantum computation has an inherent thermodynamic irreversibility.

A lower bound on heat generation exceeds the Landauer Limit in quantum computing.

Classical computing can operate under special conditions where excess heat is avoided.

Abstract

The amount of heat generated by computers is rapidly becoming one of the main problems for developing new generations of information technology. The thermodynamics of computation sets the ultimate physical bounds on heat generation. A lower bound is set by the Landauer Limit, at which computation becomes thermodynamically reversible. For classical computation there is no physical principle which prevents this limit being reached, and approaches to it are already being experimentally tested. In this paper we show that for quantum computation there is an unavoidable excess heat generation that renders it inherently thermodynamically irreversible. The Landauer Limit cannot, in general, be reached by quantum computers. We show the existence of a lower bound to the heat generated by quantum computing that exceeds that given by the Landauer Limit, give the special conditions where this excess cost may be avoided, and show how classical computing falls within these special conditions.