We may infer a transition |n⟩→|m⟩ between energy eigenstates of an open quantum system by observing the emission of a photon of Bohr frequency ωmn=(En−Em)/ℏ. In addition to the "collapses" to the state |m⟩, the measurement must also have brought into existence the pre-measurement state |n⟩. As quantum trajectories are based on past observations, the condition state will jump to |m⟩, but the state |n⟩ does not feature in any essential way. We resolve this paradox by looking at quantum smoothing and derive the time-symmetric model for quantum jumps.
|Number of pages||8|
|Journal||Reports on Mathematical Physics|
|Publication status||Published - 28 Feb 2020|
- continuous measurement
- photon counting
- quantum jumps