The Impact of Thermal Fields on Rydberg Atom Radio Frequency Sensors

TL;DR

This paper investigates how thermal radiation affects Rydberg atom RF sensors, showing that thermal fields mainly cause decoherence by increasing atomic decay rates, unlike antennas which are limited by thermal background.

Contribution

It provides a detailed analysis of the impact of thermal radiation on Rydberg atom sensors, highlighting their resilience to thermal noise compared to traditional antennas.

Findings

Thermal radiation increases decay rates of Rydberg states.

Thermal fields do not contribute to sensor coherence, only damping it.

Rydberg sensors are less affected by thermal background than antennas.

Abstract

Rydberg atom radio frequency sensors are unique in a number of ways, including possessing extraordinary carrier bandwidth, self-calibration and accuracy. In this paper, we examine the impact of thermal radiation on Rydberg atom sensors. Antennas are limited by their thermal background, while Rydberg atom sensors are coherent sensors. Incoherent thermal radiation does not limit Rydberg atom sensors in the same way as an antenna. The primary consequence of a thermal radiation field on Rydberg atom sensors is to decrease their coherence, as the decay rates of the Rydberg states used for sensing the radio frequency field are increased due to the thermal field, i.e. blackbody, modification of the atomic decay rates. Thermal and coherent field excitation are fundamentally different in that thermal fields produce statistically independent excitations with well-defined frequency, polarization, and propagation direction, while coherent states are coherent superpositions of photon number states. Consequently, thermal fields do not contribute to the coherences of the density matrix that are used for Rydberg atom sensing, except for damping them.