  No process in nature can perfectly clone an arbitrary quantum state. But is
it possible to engineer processes that replicate quantum information with
vanishingly small error? Here we demonstrate the possibility of probabilistic
super-replication phenomena where N equally prepared quantum clocks are
transformed into a much larger number of M nearly perfect replicas, with an
error that rapidly vanishes whenever M is small compared to the square of N.
The quadratic replication rate is the ultimate limit imposed by Quantum
Mechanics to the proliferation of information and is fundamentally linked with
the Heisenberg limit of quantum metrology.
