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.

量子光学在量子信息处理和量子计量的许多当代应用中发挥着重要作用。然而，这些协议的实验实现不可避免地会出现损失。这种损失有两种不同的形式，随机损失和确定性损失，它们以不同的方式影响量子力学系统。在本次博览会中，我们提供了两种形式的损失对多光子状态的影响的直接实验说明。具体来说，我们表明，在随机损失下，双光子状态的预示统计以明显的方式减少，但在存在确定性损失的情况下保持不变。该演示为熟悉基本量子力学的学生提供了多光子系统损失的直观说明，并更普遍地强调了量子理论中纯态和混合态之间的区别。本演讲面向熟悉量子光学的高年级本科生。