论文标题
历史没有崩溃
Histories without collapse
论文作者
论文摘要
本文是量子力学历史概率的两种理论的比较。一个使用投影假设源自哥本哈根量子力学，是“一致的历史”解释的基础。另一个是基于贝尔的一项建议，最初是针对“试点状态”理论的，但此处适用于纯统一量子力学。第一个可以用于更广泛的历史类别，但取决于投影假设或“崩溃”，这被广泛认为是理论的不满意特征。第二个可以用于通用状态向量理论而不会崩溃。我们检查了一个基于Wigner的朋友的简单模型，在该模型中，Bell的模型和投影假设给出了有感知系统历史的不同概率。我们还研究了该模型的Frauchiger-Renner-Renner扩展，其中两种历史计算的比较揭示了Frauchiger和Renner发现的矛盾。通过扩展模型以使观察者配备记忆，我们将历史的概率降低到一次出生规则的使用，并表明，由于与记忆的纠缠：纠缠式：纠缠式工具崩溃，带有记忆的诞生规则与在历史过程中应用投影相同。我们讨论了这对在量子宇宙学中使用历史的含义。
This paper is a comparison of two theories of the probability of a history in quantum mechanics. One is derived from Copenhagen quantum mechanics using the projection postulate and is the basis of the "consistent histories" interpretation; the other is based on a proposal by Bell, originally for the "pilot state" theory but here applied to pure unitary quantum mechanics. The first can be used for a wider class of histories but depends on the projection postulate, or "collapse", which is widely held to be an unsatisfactory feature of the theory; the second can be used in a theory of the universal state vector without collapse. We examine a simple model based on Wigner's friend, in which Bell's model and the projection postulate give different probabilities for the histories of a sentient system. We also examine the Frauchiger-Renner extension of this model, in which comparison of the two calculations of histories throws light on the contradiction found by Frauchiger and Renner. By extending the model to equip the observer with a memory, we reduce the probability of histories to the use of the Born rule at a single time, and show that the Born rule, with the memory, gives the same result as applying projection in the course of the history, because of entanglement with the memory: entanglement implements collapse. We discuss the implications of this for the use of histories in quantum cosmology.
