On the exact analysis of an idealized quantum switch

We study an entanglement distribution switch that serves k users in a star topology. The function of the switch is to facilitate end-to-end bipartite entangled state generation for pairs of users. We study a simple variant of this problem, wherein all links connecting the users to the switch are identical, the effects of state decoherence are negligible, and the switch can store an arbitrary number of qubits. We model the system using a discrete-time Markov chain and obtain the capacity of the switch. When the switch operates at capacity, we also present a numerical method for computing the expected number of qubits stored at the switch, which depends on the number of users k and the probability of successful entanglement generation at the link level p. We then compare the results of our exact analysis to that of a continuous-time Markov chain model of a quantum switch and argue that the latter is a reasonable approximation to the more realistic model presented in this work.