Cross-coupling effects in circuit-QED stimulated Raman adiabatic passage

TL;DR

This paper investigates the impact of parasitic couplings on stimulated Raman adiabatic passage (STIRAP) in circuit-QED systems, especially transmons, revealing an optimal drive amplitude for effective population transfer amid decoherence.

Contribution

It analyzes how parasitic couplings affect STIRAP in circuit-QED, identifying optimal conditions for robust state transfer in systems with harmonic energy levels.

Findings

Parasitic couplings significantly influence STIRAP efficiency.

An optimal drive amplitude exists for maximum population transfer.

Decoherence impacts the effectiveness of the protocol.

Abstract

Stimulated Raman adiabatic passage is a quantum protocol that can be used for robust state preparation in a three-level system. It has been commonly employed in quantum optics, but recently this technique has drawn attention also in circuit quantum electrodynamics. The protocol relies on two slowly varying drive pulses that couple the initial and the target state via an intermediate state, which remains unpopulated. Here we study the detrimental effect of the parasitic couplings of the drives into transitions other than those required by the protocol. The effect is most prominent in systems with almost harmonic energy level structure, such as the transmon. We show that under these conditions in the presence of decoherence there exists an optimal STIRAP amplitude for population transfer.