Spin-photon entanglement of a single Er$^{3+}$ ion in the telecom band
Spin-photon entanglement of a single Er$^{3+}$ ion in the telecom band
Long-distance quantum communication using quantum repeaters is an enabling technology for secure communication, distributed quantum computing and quantum-enhanced sensing and metrology. As a building block of quantum repeaters, spin-photon entanglement has been demonstrated with both atomic and solid-state qubits. However, previously demonstrated qubits with long spin coherence do not directly …