Bypassing the bandwidth theorem withPTsymmetry

The beat time τfpt associated with the energy transfer between two coupled oscillators is dictated by the bandwidth theorem which sets a lower bound τfpt~1/δω. We show, both experimentally and theoretically, that two coupled active LRC electrical oscillators with parity-time (PT) symmetry bypass the lower bound imposed by the bandwidth theorem, reducing the beat time to zero while retaining a real valued spectrum and fixed eigenfrequency difference δω. Our results foster design strategies which lead to (stable) pseudounitary wave evolution, and may allow for ultrafast computation, telecommunication, and signal processing.