Quantum effects in algorithms

作     者：Jozsa, R 

作者机构：Univ Plymouth Sch Math & Stat Plymouth PL4 8AA Devon England 

出 版 物：《CHAOS SOLITONS & FRACTALS》 (浑沌，孤立子与分形)

年 卷 期：1999年第10卷第10期

页      面：1657-1664页

核心收录：

学科分类：07[理学] 0701[理学-数学] 0702[理学-物理学] 070101[理学-基础数学] 

主　　题：Quantum theory 

摘      要：We discuss some seemingly paradoxical yet valid effects of quantum physics in information processing. Firstly, we argue that the act of doing nothing on part of an entangled quantum system is a highly non-trivial operation and that it is the essential ingredient underlying the computational speedup in the known quantum algorithms. Secondly, we show that the watched pot effect of quantum measurement theory gives the following novel computational possibility: suppose that we have a quantum computer with an on/off switch, programmed ready to solve a decision problem. Then (in certain circumstances) the mere fact that the computer would have given the answer if it were run, is enough for us to learn the answer, even though the computer is in fact not run. (C) 1999 Elsevier Science Ltd. All rights reserved.