  Complex absorbing potentials are frequently imposed when simulating unbound
quantum systems. While this is usually done solely in order to avoid artifacts
at the numerical boundary, we show how absorbers may also be used to probe the
characteristics of the particle undergoing absorption. This way, information
about the removed particles may be retained. Moreover, we explain how -- and
when -- such absorbers act as detectors in the sense that they allow for
simulating the act of measurement in dynamical simulations.
