Exceptional Point-enhanced Rydberg Atomic Electrometers

TL;DR

This paper demonstrates a new method for quantum electrometry using Rydberg atoms enhanced by exceptional points, achieving significantly improved sensitivity through non-Hermitian physics in a scalable, tunable system.

Contribution

It provides the first experimental realization of an EP-enhanced atomic electrometer using Rydberg atoms, with real-time tunability and substantial sensitivity improvements.

Findings

Achieved nearly 20-fold responsivity enhancement near the EP.

Realized a second-order EP in a passive thermal Rydberg system.

Demonstrated a sensitivity of 22.68 nV cm^{-1} Hz^{-1/2}.

Abstract

Rydberg atoms, with their large transition dipole moments and extreme sensitivity to electric fields, have attracted widespread attention as promising candidates for next-generation quantum precision electrometry. Meanwhile, exceptional points (EPs) in non-Hermitian systems have opened new avenues for ultrasensitive metrology. Despite increasing interest in non-Hermitian physics, EP-enhanced sensitivity has rarely been explored in Rydberg atomic platforms. Here, we provide a new theoretical understanding of Autler-Townes (AT)-based Rydberg electrometry under non-Hermitian conditions, showing that dissipation fundamentally modifies the spectral response and enables sensitivity enhancement via EP-induced nonlinearity. Experimentally, we realize a second-order EP in a passive thermal Rydberg system without requiring gain media or cryogenics, and demonstrate the first EP-enhanced atomic electrometer. The EP can be tuned in real time by adjusting laser and microwave parameters, forming a flexible and scalable platform. Near the EP, the system exhibits a square-root response, yielding a nearly 20-fold enhancement in responsivity. Using amplitude-based detection, we achieve a sensitivity of $22.68~\mathrm{nV cm^{-1} Hz^{-1/2}}$ under realistic conditions. Our work establishes a practical, tunable platform for EP-enhanced sensing and real-time control, with broad implications for quantum metrology in open systems.