[论文解读] Notwithstanding Bohr, the Reasons for QBism

Christopher A. Fuchs|arXiv (Cornell University)|May 9, 2017

Quantum Mechanics and Applications参考文献 68被引用 53

一句话总结

本文论证 QBism 是量子力学的一个不同解释，基于三个原则（Born rule 作为规范性、所有概率主观性、测量结果作为个人经验），并通过贝叶斯和信息理论思想发展，与 Bohr 有所分歧，同时对 Bohr 的概念进行重新解释。

ABSTRACT

Without Niels Bohr, QBism would be nothing. But QBism is not Bohr. This paper attempts to show that, despite a popular misconception, QBism is no minor tweak to Bohr's interpretation of quantum mechanics. It is something quite distinct. Along the way, we lay out three tenets of QBism in some detail: 1) The Born Rule---the foundation of what quantum theory means for QBism---is a normative statement. It is about the decision-making behavior any individual agent should strive for; it is not a descriptive "law of nature" in the usual sense. 2) All probabilities, including all quantum probabilities, are so subjective they never tell nature what to do. This includes probability-1 assignments. Quantum states thus have no "ontic hold" on the world. 3) Quantum measurement outcomes just are personal experiences for the agent gambling upon them. Particularly, quantum measurement outcomes are not, to paraphrase Bohr, instances of "irreversible amplification in devices whose design is communicable in common language suitably refined by the terminology of classical physics." Finally, an explicit comparison is given between QBism and Bohr with regard to three subjects: a) The issue of the "detached observer" as it arose in a debate between Pauli and Bohr, b) Bohr's reply to Einstein, Podolsky, and Rosen, and c) Bohr's mature notion of "quantum phenomena." At the end, we discuss how Bohr's notion of phenomena may have something to offer the philosophy of William James: A physics from which to further develop his vision of the world---call it an ontology if you will---in which "new being comes in local spots and patches."

研究动机与目标

• 澄清 QBism 如何与 Bohr 和 Copenhagen interpretation 区别。
• 阐述 QBism 的三个核心原则及其哲学含义。
• 解释贝叶斯概率和量子信息理论如何塑造 QBism。
• 追溯从 Bohr、Wheeler 和 Pauli 到 QBism 的历史与概念发展。
• 讨论 Bohr 的现象概念如何被 QBism 调和或重新诠释。

提出的方法

• 提出 QBism 的三个核心原则（Born rule 作为规范性、所有概率的主观性、测量结果的个人体验）。
• 描述 QBism 如何利用贝叶斯主义和量子信息理论来重新表述量子态与测量。
• 论证量子态表示个人信念，而非系统的本体属性。
• 将 QBism 的立场与 Bohr 在分离观察者、EPR 与现象方面的观点进行比较。
• 讨论塑造 QBism 的历史影响（Bohr、Wheeler、Pauli）以及当代实用主义哲学（William James）。

实验结果

研究问题

• RQ1 QBism 在概念上如何将概率、测量和态与传统解释区分开？
• RQ2 QBism 在哪些方面修订了 Bohr 的观察与现象概念？
• RQ3 QBism 如何处理类似 EPR 的相关性以及量子力学中的观察者概念？

主要发现

• QBism 将 Born rule 视为代理人决策的规范性指南，而非自然法则。
• 在 QBism 中，所有量子概率（包括概率为1的分配）都是主观的，因此量子态不具备对现实的本体性支配。
• 量子测量结果是代理人和外部系统之间的个人体验共享的，而不是以经典方式描述的不可逆放大。
• QBism 将贝叶斯个人主义与量子信息结合起来，以分离理论中的主观与客观方面，指导持续的基础研究发展。
• 该工作将 QBism 与 Bohr 区分开来，同时保留 Bohr 思想的有用方面，并将其观点与实用主义哲学以及 Wheeler 的观察者参与观点联系起来。