title: Four-domain dual-combination operation invariance and time reversal symmetry of electromagnetic fields.
abstract: Current experimental investigations about time reversal (TR) electromagnetic (EM) fields always depended on TR mirror (TRM). However, EM fields can perform reversal operation invariance in four domains connected by Fourier Transform. A multiplication table and an appropriate operating figure about EM fields' invariance are derived to describe a series of dual combined operations in the four domains, in which there are at least 10 dual-combination operations different from current TRM operations which can equivalently actualize TR symmetry. Theoretically, centrosymmetric operations of spatial position vector and spatial spectrum vector may have the potential to promote different reversal mirrors.
authors.forename: Yingming
authors.initials: Y
authors.lastname: Chen
authors.forename: Bing-Zhong
authors.initials: BZ
authors.lastname: Wang