Thermodynamic Analysis of Classical and Quantum Search Algorithms
Abstract
We analyze the performance of classical and quantum search algorithms from a thermodynamic perspective, focusing on resources such as time, energy, and memory size. We consider two examples that are relevant to post-quantum cryptography: Grover's search algorithm, and the quantum algorithm for collision-finding. Using Bennett's "Brownian" model of low-power reversible computation, we show classical algorithms that have the same asymptotic energy consumption as these quantum algorithms. Thus, the quantum advantage in query complexity does not imply a reduction in these thermodynamic resource costs. In addition, we present realistic estimates of the resource costs of quantum and classical search, for near-future computing technologies. We find that, if memory is cheap, classical exhaustive search can be surprisingly competitive with Grover's algorithm.
Cite
@article{arxiv.1709.10510,
title = {Thermodynamic Analysis of Classical and Quantum Search Algorithms},
author = {Ray Perlner and Yi-Kai Liu},
journal= {arXiv preprint arXiv:1709.10510},
year = {2017}
}