Theory of composite Ramsey sequences of radiofrequency pulses beyond the rotating wave approximation

TL;DR

This paper develops a theoretical framework for composite Ramsey sequences of radiofrequency pulses that go beyond the rotating wave approximation, revealing significant differences in dynamics crucial for tests of local Lorentz invariance.

Contribution

It introduces a Fourier analysis-based theory accounting for non-resonant effects in RF pulse sequences beyond the RWA, impacting precision tests of fundamental symmetries.

Findings

Non-resonant contributions significantly alter quantum dynamics for sequences with many pulses.

The effectiveness of RF pulse sequences in testing Lorentz invariance is affected by these non-resonant effects.

Traditional RWA-based models may be insufficient for long pulse sequences in precision experiments.

Abstract

We develop a theory of composite Ramsey sequences of rf pulses interacting with the Zeeman structure at the long-lived atomic level, beyond the rotating wave approximation. Such sequences are proposed in experiments to detect the violation of local Lorentz invariance [R. Shaniv, et al., Phys. Rev. Lett. 120, 103202 (2018)]. Based on Fourier analysis, we have shown that taking into account non-resonant contributions leads to a radical change in the dynamics of the quantum system (with respect to the rotating wave approximation) in the case when the number of Ramsey pulses exceeds several tens. As a result, the effectiveness of using such rf pulses sequences to test local Lorentz invariance has not yet been fully determined and requires additional research.