Dyson's eternal intelligence
Dyson's eternal intelligence (the Dyson Scenario), is a hypothetical concept, proposed by Freeman Dyson in 1979, by which an immortal society of intelligent beings in an open universe may escape the prospect of the heat death of the universe by performing an infinite number of computations (as defined below) even though expending only a finite amount of energy. Bremermann's limit can be invoked to deduce a lower bound on the amount of time required to distinguish two discrete energy levels of a quantum system using a quantum measurement. One can interpret this measurement as a computation on 1 bit for this system; however, Bremermann's limit is difficult to interpret physically, since there exist quantum Hamiltonians for which this interpretation would give arbitrarily fast computation speeds at arbitrarily low energy. Following this interpretation, the upper bound on the number of such measurements that can be performed grows over time. Assuming that the energy in the quantum system on which the measurement is performed is lost (while ignoring energy that is lost due to the measurement apparatus itself), the energy available from the mechanism suggested below slows logarithmically, but never stops.