Title: Directional Population Control Beyond the Exceptional Point in a Non-Hermitian System

C. He and R.R. Jones

University of Virginia, Charlottesville, VA 22904, USA

Abstract:

In the context of dynamical control, non-Hermitian systems offer unique opportunities and challenges. In the simplest case of two interacting levels with gain and/or loss, the existence of an exceptional point (EP) of degeneracy in the chiral complex eigenvalue landscape fundamentally changes how the system responds to adiabatic changes in the coupling ($\gamma$) and energy separation ($\delta$) of the bare levels. In particular, previous studies have shown that selective population transfer can be achieved by adiabatically steering the system around closed paths that encircle the EP with the proper helicity in the $\gamma$ vs $\delta$ parameter space. Here we show that efficient state-selective population transfer can, in some cases, be achieved even with control loops that do not enclose the EP.

Status: Published, Phys. Rev. A 104, 013111 (2021).