The Quantum Computing Challenge

Abstract

The laws ofphysics imposes limits on increases in computing power. Two of these limits are interconnect wires in multicomputers and thermodynamic limits to energy dissipation in conventional irreversible technology. Quantum computing is a new computational technology that promises to eliminate problems of latency and wiring associated with parallel computers and the rapidly approaching ultimate limits to computing power imposed by the fundamental thermodynamics. Moreover, a quantum computer will be able to exponentially improve known classical algorithms for factoring, and quadratically improve every classical algorithm for searching an unstructured list, as well as give various speed-ups in communication complexity, by exploiting unique quantum mechanical features. Finally, a quantum computer may be able to simulate quantum mechanical systems, something which seems out of the question for classical computers, thus reaching the ultimate goal of replacing actual quantum mechanical experiments with simulated ones. On the downside, for some problems quantum mechanical computers cannot significantly improve the performance of classical computers.

Partially supported by the European Union through NeuroCOLT II Working Group and the QAIP Project.The author is also affiliated with the University ofAmsterdam.