Trade off-Free Entanglement Stabilization in a Superconducting Qutrit-Qubit System

TL;DR

This paper presents a novel dissipative protocol for stabilizing Bell states in a superconducting qutrit-qubit system, achieving high fidelity without the typical trade-offs, and demonstrating the lowest error-time product in solid-state platforms.

Contribution

The authors introduce a trade-off-free entanglement stabilization method using purely dissipative channels in a circuit-QED system, advancing quantum state preparation techniques.

Findings

Achieved 84% fidelity in Bell state stabilization.

Demonstrated stabilization time of 339 ns.

Reported lowest error-time product in solid-state quantum platforms.

Abstract

Quantum reservoir engineering is a powerful framework for autonomous quantum state preparation and error correction. However, traditional approaches to reservoir engineering are hindered by unavoidable coherent leakage out of the target state, which imposes an inherent trade off between achievable steady-state state fidelity and stabilization rate. In this work we demonstrate a protocol that achieves trade off-free Bell state stabilization in a qutrit-qubit system realized on a circuit-QED platform. We accomplish this by creating a purely dissipative channel for population transfer into the target state, mediated by strong parametric interactions coupling the second-excited state of a superconducting transmon and the engineered bath resonator. Our scheme achieves a state preparation fidelity of 84% with a stabilization time constant of 339 ns, leading to the lowest error-time product reported in solid-state quantum information platforms to date.