Hardware-efficient stabilization of entanglement via engineered dissipation in superconducting circuits

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 the qubits' dedicated readout resonators to effectively develop nonlocal dissipative channels. Leveraging individual controllability of the qubits and resonators, the protocol stabilizes two-qubit Bell states with a fidelity of <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mrow><a:mn>90.7</a:mn><a:mo>%</a:mo></a:mrow></a:math>, marking the highest reported value in solid-state platforms to date. Furthermore, by extending this strategy to include three qubits, an entangled <b:math xmlns:b="http://www.w3.org/1998/Math/MathML"><b:mi>W</b:mi></b:math> state is achieved with a fidelity of <c:math xmlns:c="http://www.w3.org/1998/Math/MathML"><c:mrow><c:mn>86.2</c:mn><c:mo>%</c:mo></c:mrow></c:math>. This demonstrates the protocol's extensibility beyond two-qubit systems. 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.