Quantum remote sensing, also known as quantum detection and ranging (QUDAR), is the use of entangled photon states to detect targets at a stand-off distance. It inherently relies on sending many single photons through free space, bouncing off of a target and returning to the sensor. It is therefore necessary to understand how single photons interact and scatter from targets of macroscopic size. This article relates quantum and classical scattering in the far-field regime. Specifically, we show that due to the photon's position uncertainty, the path over which the photon traverses is not well defined, and this causes quantum interference. The result of this interference exactly replicates classical scattering behavior of electromagnetic waves. We will show that one can exactly derive the classical electric field scattering integral using a purely quantum construction. Although this article focuses on the context of QUDAR, it is very general to any application involving far-field electromagnetic scattering. Finally, we delve into the QUDAR multiphoton quantum scattering advantage shown in previous literature and further develop the theory. Specifically, we provide explanations as to why this advantage has not been observed in the classical regime, as well as provide insight as to the experimental requirements necessary to achieve this cross-section enhancement.

中文翻译：

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远场体系中经典和量子电磁散射的等效性

量子遥感，也称为量子探测和测距（QUDAR），是利用纠缠光子态探测远距离目标。它本质上依赖于通过自由空间发送许多单光子，从目标反弹并返回传感器。因此，有必要了解单个光子如何与宏观尺寸的目标相互作用和散射。本文涉及远场区域中的量子散射和经典散射。具体来说，我们表明由于光子的位置不确定性，光子穿越的路径没有明确定义，这会导致量子干涉。这种干扰的结果完全复制了电磁波的经典散射行为。我们将证明，可以使用纯量子结构精确地推导出经典电场散射积分。尽管本文侧重于 QUDAR 的上下文，但它对于任何涉及远场电磁散射的应用都非常通用。最后，我们深入研究了先前文献中显示的 QUDAR 多光子量子散射优势，并进一步发展了该理论。具体来说，我们解释了为什么在经典方案中没有观察到这种优势，并提供有关实现这种横截面增强所需的实验要求的见解。我们深入研究了先前文献中显示的 QUDAR 多光子量子散射优势，并进一步发展了该理论。具体来说，我们解释了为什么在经典方案中没有观察到这种优势，并提供有关实现这种横截面增强所需的实验要求的见解。我们深入研究了先前文献中显示的 QUDAR 多光子量子散射优势，并进一步发展了该理论。具体来说，我们解释了为什么在经典方案中没有观察到这种优势，并提供有关实现这种横截面增强所需的实验要求的见解。