Time-Reversal Symmetry Violation
The time-reversal symmetry violation is the most mysterious phenomenon that allows explaining the matter–antimatter asymmetry in the present Universe. This is due to the fact that the CP-symmetry violation (Lee and Yang, Phys. Rev. 106:340, 1957, ), which causes the asymmetry of matter–antimatter, also leads to a violation of T-symmetry due to the CPT theorem. According to Sakharov (JETP Lett. 5:24, 1967, ), this asymmetry could have arisen from CP-violating (and consequently, T-violating) interactions at an early stage of the Big Bang. In the course of further evolution, this led to the present structure of the Universe. The most important motivation for studying the time-reversal symmetry breaking is the fact that its origin is not completely understood.