Coherent population transfer between weakly-coupled states in a ladder-type superconducting qutrit

TL;DR

This paper demonstrates high-efficiency, robust population transfer in a superconducting qutrit using STIRAP, surpassing 99% efficiency and offering advantages over traditional methods for quantum information processing.

Contribution

The first experimental realization of STIRAP in a superconducting ladder-type qutrit with over 99% transfer efficiency and enhanced robustness.

Findings

Transfer efficiency exceeds 99%

Population in the first-excited state remains below 1%

STIRAP is more robust than resonant π pulses

Abstract

Stimulated Raman adiabatic passage (STIRAP) offers significant advantages for coherent population transfer between un- or weakly-coupled states and has the potential of realizing efficient quantum gate, qubit entanglement, and quantum information transfer. Here we report on the realization of STIRAP in a superconducting phase qutrit - a ladder-type system in which the ground state population is coherently transferred to the second-excited state via the dark state subspace. The result agrees well with the numerical simulation of the master equation, which further demonstrates that with the state-of-the-art superconducting qutrits the transfer efficiency readily exceeds $99\%$ while keeping the population in the first-excited state below $1\%$. We show that population transfer via STIRAP is significantly more robust against variations of the experimental parameters compared to that via the conventional resonant $\pi$ pulse method. Our work opens up a new venue for exploring STIRAP for quantum information processing using the superconducting artificial atoms.