Bypassing the bandwidth theorem with PT symmetry

The beat time tau(fpt) associated with the energy transfer between two coupled oscillators is dictated by the bandwidth theorem which sets a lower bound tau(fpt) similar to 1/delta omega. 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 delta omega. Our results foster design strategies which lead to (stable) pseudounitary wave evolution, and may allow for ultrafast computation, telecommunication, and signal processing.