General Signal Model and Capacity Limit for Rydberg Quantum Information System

TL;DR

This paper develops a comprehensive dynamic signal model for Rydberg atomic RF receivers, enabling better understanding and potential performance improvements over classical systems by incorporating quantum effects and noise analysis.

Contribution

It introduces a general closed-form dynamic signal response model for Rydberg atomic receivers using quantum master equations and small-signal perturbation techniques.

Findings

The model accurately predicts the receiver's response to time-varying signals.

Quantum transconductance quantifies the impact of blackbody radiation noise.

Simulations show quantum receivers can outperform classical counterparts.

Abstract

Rydberg atomic receivers represent a transformative approach to achieving high-sensitivity, broadband, and miniaturized radio frequency (RF) reception. However, existing static signal models for Rydberg atomic receivers rely on the steady-state assumption of atomic quantum states, which cannot fully describe the signal reception process of dynamic signals. To fill in this gap, in this paper, we present a general model to compute the dynamic signal response of Rydberg atomic receivers in closed form. Specifically, by applying small-signal perturbation techniques to the quantum master equation, we derive closed-form Laplace domain transfer functions that characterize the receiver's dynamic responses to time-varying signal fields. To gain more insights into the quantum-based RF-photocurrent conversion process, we further introduce the concept of quantum transconductance that describes the quantum system as an equivalent classical system. By applying quantum transconductance, we quantify the influence of in-band blackbody radiation (BBR) noise on the atomic receiver sensitivity. Extensive simulations for Rydberg atomic receivers validate the proposed signal model, and demonstrate the possibility of quantum receivers to outperform classical electronic receivers through the improvement of quantum transconductance.