General quantum measurements in relativistic quantum field theory

Single particle detection is described in a limited way by simple models of measurements in quantum field theory. We show that a general approach, using Kraus operators in spacetime constructed from natural combinations of fields, leads to an efficient model of a single particle detector. The model is free from any auxiliary objects as it is defined solely within the existing quantum field framework. It can be applied to a large family of setups where the time resolution of the measurement is relevant, such as Bell correlations or sequential measurement. We also discuss the limitations and working regimes of the model.