Anastopoulos Charis, Hu Bei-Lok
Department of Physics, University of Patras, 26500 Patras, Greece.
Maryland Center for Fundamental Physics and Joint Quantum Institute, University of Maryland, College Park, MD 20742-4111, USA.
Entropy (Basel). 2022 Mar 31;24(4):490. doi: 10.3390/e24040490.
In recent years an increasing number of papers have attempted to mimic or supplant quantum field theory in discussions of issues related to gravity by the tools and through the perspective of quantum information theory, often in the context of alternative quantum theories. In this article, we point out three common problems in such treatments. First, we show that the notion of interactions mediated by an information channel is not, in general, equivalent to the treatment of interactions by quantum field theory. When used to describe gravity, this notion may lead to inconsistencies with general relativity. Second, we point out that in general one cannot replace a quantum field by a classical stochastic field, or mock up the effects of quantum fluctuations by that of classical stochastic sources (noises), because in so doing important quantum features such as coherence and entanglement will be left out. Third, we explain how under specific conditions semi-classical and stochastic theories indeed can be formulated from their quantum origins and play a role at certain regimes of interest.
近年来，越来越多的论文试图在与引力相关问题的讨论中，通过量子信息理论的工具并从其视角来模仿或取代量子场论，这通常是在替代量子理论的背景下进行的。在本文中，我们指出这类处理中的三个常见问题。首先，我们表明由信息通道介导的相互作用概念，一般而言并不等同于用量子场论来处理相互作用。当用于描述引力时，这个概念可能导致与广义相对论不一致。其次，我们指出一般不能用经典随机场来取代量子场，或者用经典随机源（噪声）的效应来模拟量子涨落的效应，因为这样做会遗漏诸如相干性和纠缠等重要的量子特征。第三，我们解释在特定条件下，半经典和随机理论实际上如何能从它们的量子起源中构建出来，并在某些感兴趣的 regime 中发挥作用。
