标题： 时间反演对称性对电磁场的约束 显示英文标题

标题： Time-reversal-symmetry bounds on electromagnetic fields

摘要： 对于具有时间反演对称性的线性电磁系统，我们提出了一种方法，仅使用散射矩阵（S矩阵）来限制从不同端口激发的内部场的比值，改进了Sounas和Alù（2017）[Phys. Rev. Lett. 118, 154302 (2017)] 的先前相关界限。通过互易性，从内部偶极子源发出的波幅以类似方式受到限制。当应用于耦合共振系统时，我们的方法限制了共振耦合/衰减系数的比值。我们还得到了两个端口激发的场相对相位和两端口系统中场强度比值之间的关系。此外，尽管损耗系统不具有时间反演对称性，但我们仍可以仅使用无损耗S矩阵近似限制损耗引起的S矩阵非酉性。我们展示了在各种散射系统中我们界限的接近紧致性的数值验证。 显示英文摘要

摘要： For linear electromagnetic systems possessing time-reversal symmetry, we present an approach to bound ratios of internal fields excited from different ports, using only the scattering matrix (S matrix), improving upon previous related bounds by Sounas and Al\`u (2017) [Phys. Rev. Lett. 118, 154302 (2017)]. By reciprocity, emitted-wave amplitudes from internal dipole sources are bounded in a similar way. When applied to coupled-resonant systems, our method constrains ratios of resonant coupling/decay coefficients. We also obtain a relation for the relative phase of fields excited from the two ports and the ratio of field intensities in a two-port system. In addition, although lossy systems do not have time-reversal symmetry, we can still approximately bound loss-induced non-unitarity of the S matrix using only the lossless S matrix. We show numerical validations of the near-tightness of our bounds in various scattering systems.