论文标题
从不确定因果秩序中重新评估热力学优势
Reassessing thermodynamic advantage from indefinite causal order
论文作者
论文摘要
不确定的因果秩序是量子高阶转换研究所涉及的关键特征。最近,激进的研究集中在与缺乏量子过程的因果关系秩序相关的可能优势上。通常,量子开关被称为信息理论和热力学任务的优势。我们在这里解决一个问题,无限期因果秩序是否是量子热力学的资源。受到文献的先前结果的启发,我们表明无限期的因果秩序对于报告的自由能和麦内氏疗法的增加并不是必需的。更具体地说,我们表明,一个简单的因果有序过程,该过程在最终测量之前用新的状态代替了系统状态,在迄今为止考虑的所有热力学任务中都优于量子开关。我们进一步表明,如果我们允许系统和环境之间的非马克维亚相互作用,也可以在不完全丢弃系统的情况下实现类似的优势。我们将分析扩展到不确定因果秩序的更极端例子,表明它们也没有提供优势。最后,我们讨论了研究在一般情况下不确定因果秩序可能产生的优势的可能方法。
Indefinite causal order is a key feature involved in the study of quantum higher order transformations. Recently, intense research has been focused on possible advantages related to the lack of definite causal order of quantum processes. Quite often the quantum switch is claimed to provide advantages in information-theoretic and thermodynamic tasks. We address here the question whether indefinite causal order is a resource for quantum thermodynamics. Inspired by previous results in the literature, we show that indefinite causal order is not necessary for the reported increase in free energy and ergotropy. More specifically, we show that a simple causally ordered process, which replaces the system's state with a new one before the final measurement, outperforms the quantum switch in all thermodynamic tasks considered so far. We further show that a similar advantage can be also achieved without completely discarding system, if we allow for non-Markovian interactions between the system and an environment. We extend the analysis to more extreme examples of indefinite causal order, showing that they do not provide an advantage either. Finally, we discuss a possible way to study the advantages that may arise from indefinite causal order in a general scenario.