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  • Featured in Physics
  • Open Access

Distributing Stationary Qubit Entanglement through a Nonlocal Squeezed Reservoir

A. Andrés-Juanes1,*, J. Agustí2,3,4,5, R. Sett1, E. S. Redchenko1,†, L. N. Kapoor1, S. Hawaldar1, P. Rabl2,3,4, and J. M. Fink1,‡

  • *Contact author: Alejandro.AndresJuanes@ist.ac.at
  • †Present address: Vienna Center for Quantum Science and Technology, Atominstitut, TU Wien, 1020 Vienna, Austria.
  • ‡Contact author: jfink@ist.ac.at
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Phys. Rev. X 16, 031005 – Published 13 July, 2026

DOI: https://doi.org/10.1103/r4jt-j39w

Abstract

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 rely on deterministic state transfer, or probabilistic protocols that require active control or measurements and postselection. Here, we demonstrate a fundamentally different, fully autonomous process, where two remote qubits are entangled through their coupling to a quantum-correlated photonic reservoir. In our experiment, a Josephson parametric converter produces a Gaussian, continuous-variable entangled state of propagating microwave fields that drives two spatially separated superconducting transmon qubits into a stationary, discrete-variable entangled state. We also show how qubit tomography unlocks a direct and sensitive verification of two-mode squeezing in the microwave domain. These results establish networks of qubits interfaced with distributed continuous-variable entangled states as a powerful platform for foundational studies and quantum-technology applications.

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Physics Subject Headings (PhySH)

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Entanglement Goes Steady

Published 13 July, 2026

Two independent groups have demonstrated ways to entangle quantum bits without the need for precisely timed control pulses.

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Popular Summary

The distribution of entanglement across distant qubits remains a central challenge for the operation of scalable quantum computers and large quantum networks. To address this, we demonstrate a fully autonomous process where two spatially separated superconducting transmon qubits are entangled through their coupling to a quantum-correlated photonic reservoir. By driving the qubits with a two-mode squeezed state of propagating microwave fields, we show that this shared environment naturally stabilizes the qubits in an entangled steady state without requiring active control or synchronized pulses. Furthermore, we show that qubit tomography provides a direct and sensitive verification of the two-mode squeezing present in the itinerant microwave signals. We anticipate that this mechanism provides a robust foundation for high-throughput entanglement distribution in complex local area networks and fault-tolerant quantum computation.

See Also

Autonomous Stabilization of Remote Entanglement in a Cascaded Quantum Network

Abdullah Irfan, Kaushik Singirikonda, Mingxing Yao, Andrew Lingenfelter, Michael Mollenhauer, Xi Cao, Aashish A. Clerk, and Wolfgang Pfaff
Phys. Rev. X 16, 031004 (2026)

Article Text

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Phys. Rev. X 16, 031005– Published 13 July, 2026
  • Received 17 November 2025
  • Accepted 29 April 2026
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