空间有界域中的电磁标量积
The electromagnetic scalar product in spatially-bounded domains
AI总结：
针对现有电磁标量积表达式无法直接适用于空间有界域内电磁场的问题，本文推导了仅含闭合曲面积分的辐射场电磁标量积表达式，可用于计算光脉冲的光子数等物理量，扩展了Maxwell求解器的功能。
摘要：
电磁场的许多具有物理意义的量都可以通过电磁标量积计算得到。然而，当电磁场仅在空间有界域内已知时（许多数值Maxwell求解器正是这种情况），现有的这类标量积表达式都无法直接适用。本文中，我们推导了辐射场之间电磁标量积的一个表达式，该表达式仅涉及闭合空间曲面上的积分。基于该表达式可以直接得到具有入射或出射特性的通用多色光脉冲的光子数、能量和螺旋度公式。由此，空间有界计算域中常用Maxwell求解器的功能得到了扩展，例如可通过一种直接的方法对发射场进行归一化，使其包含单个光子。
英文摘要：
Many physically interesting quantities of the electromagnetic field can be computed using the electromagnetic scalar product. However, none of the existing expressions for such scalar product are directly applicable when the fields are only known in a spatially-bounded domain, as is the case for many numerical Maxwell solvers. In here, we derive an expression for the electromagnetic scalar product between radiation fields that only involves integrals over closed spatial surfaces. The expression readily leads to formulas for the number of photons, energy, and helicity of generic polychromatic light pulses of incoming or outgoing character. The capabilities of popular Maxwell solvers in spatially-bounded computational domains are thereby augmented, for example, by a straightforward method for normalizing emitted fields so that they contain a single photon.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
