We study the waiting-time distributions (WTDs) of quantum chains coupled to two Lindblad baths at each end. Our focus is on free fermion chains, where we derive closed-form expressions in terms single-particle matrices, allowing one arbitrarily large chain sizes. In doing so, also formulas for 2-point correlation functions involving non-Hermitian propagators.

Today, in a competitive market, service organizations and producers have a great attention to optimization and customer satisfaction in order to become competitive. Service organization must reduce the number of arrival, waiting time and service time in the queue to increase the customer satisfaction. In this paper by the aim of queuing theory we analyze the optimal amount of increment in a rep...