Dynamic chip assignment improves fidelity in quantum repeaters

Jeroen Grimbergen and colleagues at QuTech, TU Delft, demonstrate a new dynamic multiplexing policy for quantum repeaters that improves the fidelity of entanglement distribution. Their work focuses on systems where, on average, less than one entangled link is successfully generated per communication cycle, a realistic constraint for building near-term quantum networks. The team proposes a reconfigurable router that dynamically assigns quantum chips to either end node in every cycle, and shows this approach significantly improves entanglement quality over fixed assignment policies while only marginally impacting the rate of entanglement generation. This makes dynamic multiplexing particularly relevant for developing practical quantum communication systems. Each quantum chip within the multiplexed repeater incorporates both a communication qubit and a distinct memory qubit, enabling both entanglement generation and storage. The communication qubit functions as the interface for establishing entanglement between chips, while the memory qubit preserves this entanglement for later use. A reconfigurable router interconnects these chips, dynamically assigning each to either of the two end nodes in every communication cycle, a key feature of…