[论文解读] A free energy principle for a particular physics

Karl Friston|arXiv (Cornell University)|Jun 24, 2019

Advanced Thermodynamics and Statistical Mechanics参考文献 197被引用 234

一句话总结

本文勾勒了一个理论：Markov blankets 使得贝叶斯力学框架成为可能，将内部状态解释为对外部状态的推断，在自由能原则下连接量子力学、统计力学和经典力学。

ABSTRACT

This monograph attempts a theory of every 'thing' that can be distinguished from other things in a statistical sense. The ensuing statistical independencies, mediated by Markov blankets, speak to a recursive composition of ensembles (of things) at increasingly higher spatiotemporal scales. This decomposition provides a description of small things; e.g., quantum mechanics - via the Schrodinger equation, ensembles of small things - via statistical mechanics and related fluctuation theorems, through to big things - via classical mechanics. These descriptions are complemented with a Bayesian mechanics for autonomous or active things. Although this work provides a formulation of every thing, its main contribution is to examine the implications of Markov blankets for self-organisation to nonequilibrium steady-state. In brief, we recover an information geometry and accompanying free energy principle that allows one to interpret the internal states of something as representing or making inferences about its external states. The ensuing Bayesian mechanics is compatible with quantum, statistical and classical mechanics and may offer a formal description of lifelike particles.

研究动机与目标

• 通过 Markov blankets 在统计意义上激发一个万物理论的动机。
• 描述跨尺度的系综递归组合如何产生小尺度和大尺度的物理描述。
• 介绍面向自主或主动实体的贝叶斯力学，并将其与非平衡稳态下的自组织相关联。

提出的方法

• 发展一个信息几何视角，导出自由能原理。
• 展示在 Markov blankets 内部状态如何表示或推断外部状态。
• 推导与量子力学、统计力学和经典力学相兼容的贝叶斯力学。

实验结果

研究问题

• RQ1 Markov blankets 是否能够在跨尺度上支持对物理系统的普遍统计分解？
• RQ2 通过贝叶斯力学的自由能原理如何描述在非平衡稳态下的自组织？
• RQ3 在量子、统计和经典范畴中，内部状态在何种意义上可以被解读为对外部状态的推断？

主要发现

• 提出一个以 Markov blankets 为基础的统一信息几何框架。
• 推导出一个自由能原理，使内部状态能够编码对外部状态的推断。
• 展示贝叶斯力学与量子、统计和经典描述的兼容性。