  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, a.k.a. particle detectors. In
this work, 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 which would not be otherwise accessible.
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.
