Many states of linear real scalar quantum fields (in particular Reeh–Schlieder states) on flat as well as curved spacetime are entangled on spacelike separated local algebras of observables. It has been argued that this entanglement can be ‘harvested’ by a pair of so-called particle detectors, for example singularly or non-locally coupled quantum mechanical harmonic oscillator Unruh detectors. In an attempt to avoid such imperfect coupling, we analyse a model-independent local and covariant entanglement harvesting protocol based on the local probes of a recently proposed measurement theory of quantum fields. We then introduce the notion of a local particle detector concretely given by a local mode of a linear real scalar probe field on possibly curved spacetime and possibly under the influence of external fields. In a non-perturbative analysis we find that local particle detectors cannot harvest entanglement below a critical coupling strength when the corresponding probe fields are initially prepared in quasi-free Reeh–Schlieder states and are coupled to a system field prepared in a quasi-free state. This is a consequence of the fact that Reeh–Schlieder states restrict to truly mixed states on any local mode.

平面和弯曲时空中的线性实标量量子场的许多状态（特别是 Reeh-Schlieder 状态）都纠缠在类似空间的分离局部可观代数上。已经认为，通过一对所谓的粒子探测器的该缠结可以“收获”，例如单独或非局部耦合量子机械谐振子 Unruh 探测器。为了避免这种不完美的耦合，我们基于最近提出的量子场测量理论的局部探针分析了一种独立于模型的局部和协变纠缠收集协议。然后，我们引入了局部粒子探测器的概念，具体由线性实标量探测场的局部模式在可能弯曲的时空中并可能在外部场的影响下给出。在非微扰分析中，我们发现当相应的探测场最初以准自由 Reeh-Schlieder 状态准备并耦合到以准自由状态准备的系统场时，局部粒子探测器无法在临界耦合强度以下收获纠缠.