  Charge-based quantum computation can be attained through reliable control of
single electrons in lead-less quantum systems. Single-charge transitions in
electrically-isolated double quantum dots (DQD) realised in phosphorus-doped
silicon can be detected via capacitively coupled single-electron tunnelling
devices. By means of time-resolved measurements of the detector's conductance,
we investigate the dots' occupancy statistics in temperature. We observe a
significant reduction of the effective electron temperature in the DQD as
compared to the temperature in the detector's leads. This sets promises to make
isolated DQDs suitable platforms for long-coherence quantum computation.
