Quantum field theory is completely characterized by the field correlations between spacetime points. In turn, some of these can be accessed by locally coupling to the field simple quantum systems, also known as particle detectors. In this letter we consider what happens when a quantum-controlled superposition of detectors at different space-time points is used to probe the correlations of the field. We show that, due to quantum interference effects, two detectors can gain information on field correlations that would not be accessible, otherwise. This has relevant consequences for information theoretic quantities, like entanglement and mutual information harvested from the field. In particular, the quantum control allows for extraction of entanglement in scenarios where this is, otherwise, provably impossible.

中文翻译：

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量子时间叠加：量子场论的案例

量子场论的特征是时空点之间的场相关性。反过来，其中一些可以通过局部耦合到现场简单量子系统（也称为粒子检测器）来访问。在这封信中，我们考虑了使用不同时空点的探测器的量子控制叠加来探测场的相关性会发生什么。我们表明，由于量子干扰效应，两个检测器可以获得关于磁场相关性的信息，否则这些信息将无法访问。这对信息理论量（例如从现场收集的纠缠和相互信息）具有相关的影响。尤其是，量子控制可以在纠缠不可能的情况下提取纠缠。