Attosecond chronoscopy are measurement techniques for attosecond-scale delays of atomic and molecular single photon processes like photoemission[1] and photoionization.
Ionization-delay measurements in atomic targets provide information about the timing of the photoelectric effect, resonances, electron correlations, and transport.
Attosecond chronoscopy deals with the time-resolved observation of ultrafast electronic processes of quantum physics of matter with applications to atoms, molecules.
Realtime observations of such processes became possible with the availability of well-controlled subfemtosecond laser pulses.
Important applications are non-stationary and decaying states, quantum transport and charge migration, irreversible processes (the "Arrow of time") and the loss of phase information called decoherence of a quantum system due to its interaction with the environment.