In many complex systems, whether biological or artificial, the thermodynamic costs of communication among their components are large. These systems also tend to split information transmitted between any two components across multiple channels. A common hypothesis is that such inverse multiplexing strategies reduce total thermodynamic costs. So far, however, there have been no physics-based results supporting this hypothesis. This gap existed partially because we have lacked a theoretical framework that addresses the interplay of thermodynamics and information in off-equilibrium systems at any spatiotemporal scale. Here we present the first study that rigorously combines such a framework, stochastic thermodynamics, with Shannon information theory. We develop a minimal model that captures the fundamental features common to a wide variety of communication systems. We find that the thermodynamic cost in this model is a convex function of the channel capacity, the canonical measure of the communication capability of a channel. We also find that this function is not always monotonic, in contrast to previous results not derived from first principles physics. These results clarify when and how to split a single communication stream across multiple channels. In particular, we present Pareto fronts that reveal the trade-off between thermodynamic costs and channel capacity when inverse multiplexing. Due to the generality of our model, our findings could help explain empirical observations of how thermodynamic costs of information transmission make inverse multiplexing energetically favorable in many real-world communication systems.

翻译：在许多复杂系统中，无论是生物系统还是人工系统，其组件间通信的热力学成本都相当可观。这类系统还倾向于将任意两个组件之间传输的信息分散到多个通道中。一个常见的假设是，这种反向多路复用策略能够降低总热力学成本。然而，迄今为止，尚缺乏基于物理学的理论结果来支持这一假设。这一空白部分源于我们缺少一个能够处理非平衡系统中热力学与信息交互（并适用于任意时空尺度）的理论框架。本文首次将随机热力学这一严谨框架与香农信息论相结合。我们建立了一个最小模型，该模型捕捉了各类通信系统普遍具备的基本特征。研究发现，在该模型中，热力学成本是信道容量（衡量信道通信能力的标准指标）的凸函数。同时，与先前并非基于第一性原理推导的结果不同，该函数并非始终单调。这些结果阐明了何时以及如何将单一通信流分割到多个通道中。特别地，我们展示了帕累托前沿，揭示了反向多路复用中热力学成本与信道容量之间的权衡关系。由于模型的普适性，我们的发现有助于解释实证观测结果：为何在众多现实通信系统中，信息传输的热力学成本使得反向多路复用在能量上更为有利。