What Do We Learn from Atomic Physics about Fundamental Symmetries?
  Valuable information on interactions violating $P$- and $T$-invariance can be extracted from atomic experiments. The hypothesis of a large weak matrix element between single-particle states in heavy nuclei, $\sim 100$ eV, is ruled out by measurements of parity nonconservation in atoms. Experimental upper limit on the electric dipole moment of the $^{199}$Hg atom strictly constrains parameters of $CP$-violation models. Upper limit on the $T$-odd, $P$-even admixture to nuclear forces is set: $\alpha_T\,<\,10^{-11}$. 
I.B. Khriplovich