Bypassing the bandwidth theorem with PT symmetry

TL;DR

This paper demonstrates experimentally and theoretically that PT-symmetric coupled oscillators can bypass the bandwidth theorem's lower bound on beat time, enabling ultrafast energy transfer while maintaining real spectra.

Contribution

It introduces a method to bypass the bandwidth theorem using PT symmetry in coupled oscillators, enabling zero beat time with real eigenvalues.

Findings

Experimental verification of beat time reduction to zero.

Theoretical model confirming PT symmetry bypasses bandwidth limit.

Potential applications in ultrafast computation and communication.

Abstract

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}\sim 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 new design strategies which lead to (stable) pseudo-unitary wave evolution, and may allow for ultrafast computation, telecommunication, and signal processing.