Illustration of the single-shot/single-spin quantum dot readout scheme used in Ref. . A tunnel contact in proximity to the quantum dot has a Fermi energy tuned between the two Zeeman states of an electron trapped in the quantum dot. The spin-up state |↑〉 leads to a discharge transition of the trapped electron into the metal contact followed by a recharge transition into the energetically lower Zeeman state. The spin-down state |↓〉 cannot discharge. Thus detection of the spin is possible by transient observation of discharge/recharge transitions.