No Quantum Process Can Explain the Existence of the Preferred Basis: Decoherence Is Not Universal

作     者：Hitoshi Inamori Hitoshi Inamori

作者机构：Société Générale Boulevard Franck Kupka Puteaux France 

出 版 物：《Journal of Quantum Information Science》 (量子信息科学期刊（英文）)

年 卷 期：2016年第6卷第3期

页      面：214-222页

学科分类：07[理学] 070201[理学-理论物理] 0702[理学-物理学] 

主　　题：Quantum Mechanics Measurement Preferred Basis Entanglement 

摘      要：Environment induced decoherence, and other quantum processes, have been proposed in the literature to explain the apparent spontaneous selection—out of the many mathematically eligible bases—of a privileged measurement basis that corresponds to what we actually observe. This paper describes such processes, and demonstrates that—contrary to common belief—no such process can actually lead to a preferred basis in general. The key observation is that environment induced decoherence implicitly assumes a prior independence of the observed system, the observer and the environment. However, such independence cannot be guaranteed, and we show that environment induced decoherence does not succeed in establishing a preferred measurement basis in general. We conclude that the existence of the preferred basis must be postulated in quantum mechanics, and that changing the basis for a measurement is, and must be, described as an actual physical process.