Hardware-Efficient Stabilization of Entanglement via Engineered Dissipation in Superconducting Circuits

TL;DR

This paper presents a practical, hardware-efficient method for stabilizing entangled states in superconducting circuits using engineered dissipation, achieving record fidelities for Bell and W states.

Contribution

The authors introduce an experimentally demonstrated stabilization protocol compatible with standard superconducting circuits, enabling high-fidelity entanglement without specialized hardware.

Findings

Achieved 90.7% fidelity for Bell states

Extended protocol to stabilize W states with 86.2% fidelity

Utilized existing hardware, simplifying experimental implementation

Abstract

Generation and preservation of quantum entanglement are among the primary tasks in quantum information processing. State stabilization via quantum bath engineering offers a resource-efficient approach to achieve this objective. However, current methods for engineering dissipative channels to stabilize target entangled states often require specialized hardware designs, complicating experimental realization and hindering their compatibility with scalable quantum computation architectures. In this work, we propose and experimentally demonstrate a stabilization protocol readily implementable in the mainstream integrated superconducting quantum circuits. The approach utilizes a Raman process involving a resonant (or nearly resonant) superconducting qubit array and their dedicated readout resonators to effectively emerge nonlocal dissipative channels. Leveraging individual controllability of the qubits and resonators, the protocol stabilizes two-qubit Bell states with a fidelity of $90.7\%$, marking the highest reported value in solid-state platforms to date. Furthermore, by extending this strategy to include three qubits, an entangled $W$ state is achieved with a fidelity of $86.2\%$, which has not been experimentally investigated before. Notably, the protocol is of practical interest since it only utilizes existing hardware common to standard operations in the underlying superconducting circuits, thereby facilitating the exploration of many-body quantum entanglement with dissipative resources.