Synchronization of parametrically pumped electron oscillators with phase bistability

Stochastic motions of parametrically pumped electron oscillators synchronize abruptly when the pump power exceeds a threshold and the oscillators are radiatively cooled in a cylindrical Penning trap. Self-organized collective behavior far from thermal equilibrium is manifested by the coherent, phase-bistable motion of the electrons' center of mass, which was observed. Synchronized electrons are an ideal probe of the radiation field of a trap cavity, opening the way to a new generation of electron magnetic-moment measurements and to sideband cooling of an electron motion to mK temperatures.