Heralded entanglement between solid-state qubits separated by three metres

By Hannes Bernien, B. Hensen, W. Pfaff, G. Koolstra, M. Blok, L. Robledo, Tim Taminiau, M. Markham, Daniel J. Twitchen, L. Childress and 1 more. Nature, 2012

1,168 citations recorded by the source corpus.

Quantum entanglement between spatially separated objects is one of the most intriguing phenomena in physics. The outcomes of independent measurements on entangled objects show correlations that cannot be explained by classical physics. As well as being of fundamental interest, entanglement is a unique resource for quantum information processing and communication. Entangled quantum bits (qubits) can be used to share private information or implement quantum logical gates. Such capabilities are particularly useful when the entangled qubits are spatially separated, providing the opportunity to create highly connected quantum networks or extend quantum cryptography to long distances. Here we report entanglement of two electron spin qubits in diamond with a spatial separation of three metres. We establish this entanglement using a robust protocol based on creation of spin–photon entanglement at each location and a subsequent joint measurement of the photons. Detection of the photons heralds the projection of the spin qubits onto an entangled state. We verify the resulting non-local quantum correlations by performing single-shot readout on the qubits in different bases. The long-distance entanglement reported here can be combined with recently achieved initialization, readout and entanglement operations on local long-lived nuclear spin registers, paving the way for deterministic long-distance teleportation, quantum repeaters and extended quantum networks.

Subfields: Artificial Intelligence, Atomic and Molecular Physics, and Optics, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/38165bf64149656dfc7d6367d8ceb9b6bfaf1912

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Citations in the corpus

Generation of heralded entanglement between distant hole spins (2015, background): “Here, we demonstrate heralded quantum entanglement [6–9] of two quantum dot heavyhole spins separated by 5 meters using single-photon interference.”
Isolated Spin Qubits in SiC with a High-Fidelity Infrared Spin-to-Photon Interface (2017, positive): “In addition, ionization and spectral hopping are further hindrances in NVexperiments, and we have never observed either effect in our experiments on divacancies (see Supplemental Material [41]) [1,56,60].”
Robust quantum-network memory using decoherence-protected subspaces of nuclear spins (2016, methodology): “Compared to our previous remote entanglement experiments [13,21,22], the use of higher magnetic fields requires a second laser beam because of the comparably large ground state Zeeman splitting between j − 1i and j þ 1i of about 2 GHz.”
A link layer protocol for quantum networks (2019, background): “Such qubits can be emitted from quantum nodes [12, 13, 75], but”