Response of optical atomic clocks to transient variations in fundamental constants

This study focuses on the response of optical atomic clocks to any type of transient effects, especially for variations in fundamental constants. Considering detailed aspects of a typical optical atomic clock operation and the mechanism of servo action we develop a model of clock response to short variations. Our theoretical studies and simulations demonstrate that for events lasting a comparable time to the response time of the feedback loop, the clock’s sensitivity to variations in fundamental constants may decrease depending on the feedback-loop gain and the clock’s mode of operation. We propose leveraging active optical clocks as a novel approach to detecting short-term events, highlighting a significant difference between passive optical atomic clocks and their active counterparts. The analytical formulas presented account for the impact of servo on the final results, particularly in the case of cross-correlation analysis. Based on the obtained results, we correct previously published results. • A novel analysis of optical atomic clocks’ response to transient α variations is presented. • Servo-related sensitivity effects are quantified through analytical and numerical methods. • A practical analytical formula is derived to correct for servo effects in clock response. • Use of active and interleaved clocks is proposed for detecting rapid transients. • Limits on short-time variability of α are corrected using new analysis.