Robust population inversion in three-level systems by composite pulses

TL;DR

This paper presents a method using composite pulses to achieve robust population inversion in three-level quantum systems, effectively compensating errors and maintaining high fidelity even under decoherence.

Contribution

The authors design a composite pulse sequence that compensates systematic errors to any order, enhancing robustness in three-level quantum systems.

Findings

High-fidelity population inversion achieved with composite pulses.

Robust performance under waveform deformations and short delays.

Effective preparation of W state in superconducting circuits.

Abstract

In this work, we exploit the idea of composite pulses to achieve robust population inversion in a three-level quantum system. The scheme is based on the modulation of the coupling strength, while the other physical parameters remain unchanged. The composite pulses sequence is designed by vanishing high-order error terms, and can compensate the systematic errors to any desired order. In particular, this scheme keeps a good performance under the disturbance of waveform deformations. This trait ensures that population inversion can be nearly obtained even when the pulse sequence has a short jump delay. As an example, we employ the designed composite pulse sequence to prepare the W state in a robust manner in the superconducting circuits. The numerical results show that the fidelity can still maintain a high level in a decoherence environment.