Photonic networking of quantum memories in high dimensions

Quantum networking enables the exchange of quantum information between physically separated quantum systems, which has applications ranging from quantum computing to unconditionally secure communication. These quantum information is generally represented by two-level quantum systems or qubits. Here, we demonstrate a quantum network of high-dimensional (HD) quantum memories or "qudits" stored in individual atoms. The interference and detection of HD time-bin-encoded single photons emitted from atomic qudit memories herald maximally entangled Bell states across pairs of atomic qudit levels. This approach expands the quantum information capacity of a quantum network while improving the entanglement success fraction beyond the standard 50% limit of qubit-based measurement protocols.