Speaker: Alejandro Andrés-Juanes
Affiliation: Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria
Date: Wednesday, 24 September 2025 at 12:00
Location: Seminar Room, Serrano 121 (CFMAC)
The distribution of entanglement across distant qubits is a central challenge for the operation of scalable quantum computers and large-scale quantum networks. Existing approaches to achieve this task rely on active state transfer schemes or probabilistic protocols that require precise pulse control or measurements and postselection. Here we demonstrate a fully autonomous alternative where two remote qubits are entangled via a quantum-correlated photonic reservoir. In this hybrid approach, a Josephson parametric amplifier produces a continuous-variable entanglement state of propagating microwave fields that drive two separated superconducting transmon qubits into a stationary, discrete-variable entangled state. In a proof-of-principle experiment, we observe steady-state entanglement with concurrence C = 0.1 over a separation of 1 m, with clear pathways for further substantial improvements and extensions to multi-qubit settings. Beyond entanglement distribution, we show how the qubits can be used for the certification of continuous variable entanglement at cryogenic temperatures and without relying on noisy pre-amplification. These results establish qubits interfaced with distributed continuous-variable entangled states as a powerful new platform for a wide range of quantum technology applications.