论文标题
在存在量子共同原因的情况下量化因果影响
Quantifying causal influences in the presence of a quantum common cause
论文作者
论文摘要
量子力学对我们自然界的因果关系的直觉挑战。必须重新考虑一些基本概念，包括赖兴巴赫的共同原因原则或当地现实主义的概念。传统上，这是由于违反铃铛不平等而见证的。但是贝尔的不平等是量子相关性和因果理论之间不兼容的唯一签名吗？在这个问题的推动下，我们引入了一个通用框架，能够估计两个变量之间的因果影响，而无需干预措施，而不论经典，量子，甚至是普通原因的量词性质。特别是，通过考虑最简单的工具场景 - 不可能违反贝尔的不平等现象 - 我们表明，每个纯粹的二分之一的纠缠状态都违反了对因果影响的经典界限，从而在负面的问题上回答了一个负面的问题，并为探索量化理论中的因果关系的新场地开辟了一个新的场所。
Quantum mechanics challenges our intuition on the cause-effect relations in nature. Some fundamental concepts, including Reichenbach's common cause principle or the notion of local realism, have to be reconsidered. Traditionally, this is witnessed by the violation of a Bell inequality. But are Bell inequalities the only signature of the incompatibility between quantum correlations and causality theory? Motivated by this question we introduce a general framework able to estimate causal influences between two variables, without the need of interventions and irrespectively of the classical, quantum, or even post-quantum nature of a common cause. In particular, by considering the simplest instrumental scenario -- for which violation of Bell inequalities is not possible -- we show that every pure bipartite entangled state violates the classical bounds on causal influence, thus answering in negative to the posed question and opening a new venue to explore the role of causality within quantum theory.
