The impact of distinct loss mechanisms on multi-photon states

Abstract

Abstract Quantum optics plays an important role in many contemporary applications of quantum information processing and quantum metrology. Experimental implementations of these protocols, however, inevitably exhibit loss. This loss has two distinct forms, stochastic loss and deterministic loss, which impact quantum mechanical systems in distinct ways. In this exposition, we offer a straightforward experimental illustration of the impact of both forms of loss on multi-photon states. Specifically, we show that heralding statistics for two-photon states decrease in the obvious way under stochastic loss, and yet are unchanged in the presence of deterministic loss. This demonstration offers an intuitive clarification of loss for multi-photon systems for the student familiar with elementary quantum mechanics, and emphasizes the difference between pure and mixed states in quantum theory more generally. This presentation is targeted towards advanced undergraduate students familiar with quantum optics.