Aging and reliability of quantum networks

Quantum information science may lead to technological breakthroughs in computing, cryptography, and sensing. For the implementation of these tasks, however, complex devices with many components are needed and the quantum advantage may easily be spoiled by the failure of only a few parts. A paradigmatic example is quantum networks. There, not only do noise sources such as photon absorption or imperfect quantum memories lead to long waiting times and low fidelity, but also hardware components may break, leading to a dysfunctionality of the entire network. For the successful long-term deployment of quantum networks in the future, it is important to take such deterioration effects into consideration during the design phase. Using methods from reliability theory and the theory of aging, we develop an analytical approach for characterizing the functionality of networks under aging and repair mechanisms, also for nontrivial topologies. Combined with numerical simulations, our results allow us to optimize long-distance entanglement distribution under aging effects.