Coherent control techniques in three-level quantum sensing

TL;DR

This paper explores how coherent control techniques can amplify and detect small control errors in three-level quantum systems, enhancing the precision of quantum sensing through pulse sequence analysis.

Contribution

It introduces a method to measure weak control errors in three-level quantum systems by using coherent amplification with pulse sequences, analyzing effects of Hamiltonian fluctuations.

Findings

Sensitivity to errors can be significantly amplified by control pulse sequences.

Population transfer fidelity is affected by Rabi frequency fluctuations and static detuning.

The method provides an accurate way to sense weak errors in quantum systems.

Abstract

Quantum coherent control of a quantum system with high-fidelity is rather important in quantum computation and quantum information processing. There are many control techniques to reach these targets, such as resonant excitation, adiabatic passages, shortcuts to adiabaticity, and so on. However, for a single pulse to realize population transfer, the external tiny error has a trivial influence on the final population. The repeated application of the same pulse will greatly amplify the error effect, making it easy to be detected. Here, we propose to measure small control errors in three-level quantum systems by coherent amplification of their effects, using several coherent control techniques. For the two types of Hamiltonian with SU(2) dynamic symmetry, we analyze how the fidelity of population transfer are affected by Rabi frequencies fluctuation and static detuning deviation, based on the pulse sequence with alternating and same phases, respectively. It is found that the sensitivity of detecting these errors can be effectively amplified by the control pulse sequences. Furthermore, we discuss the efficiency of sensing the two errors with these control techniques by comparing the full width at half maximum of the population profiles. The results provide an accurate and reliable way for sensing the weak error in three-level quantum systems by applying repeatedly the coherent control pulse.