Simulation of a 1025-node quantum repeater chain of NV centres with NetSquid, a new discrete-event quantum-network simulator

We simulate quantum repeater chains of up to 1025 nodes holding nitrogen-vacancy (NV) centres as quantum processors. We model qubit decoherence, timing and fidelity of both gates and readout according to experimental data. The model also incorporates scheduling operations on the quantum state as imposed by the physics of NV centres. For example, the presence of a single communication qubit, the electron spin, only allows for entanglement generation with one remote node simultaneously. As a consequence of the accurate modelling, the numerical results indicate directions for future hardware development. In particular, we analyse the sensitivity of hardware parameters on the performance of the entire repeater chain. We also perform optimisation over several parameters and configurations, such as the number of NV centres in a single node and the scheduling for entanglement purification steps.

For these simulations, we have developed a generic quantum-network discrete-event simulator called NetSquid, which is capable of simulating decoherence together with imperfect quantum-state operations and stochastic feedback loops.