Effects of beyond-mean-field correlations on nuclear Schiff moments

We compute the nuclear Schiff moments of the diamagnetic atoms ${}^{129}$Xe, ${}^{199}$Hg, and ${}^{225}$Ra in multireference covariant density functional theory. Beyond-mean-field correlations, arising from symmetry restoration and shape mixing, are incorporated via the generator coordinate method with projection onto states with well-defined parity, particle number, and angular momentum. Our results reveal a correlation between the contributions of nuclear intermediate states to Schiff moments and the electric dipole transition strengths from these states to the ground state. The new beyond-mean-field effects can either enhance or suppress the Schiff moments. In ${}^{225}$Ra, they do the latter, reducing the enhancement from octupole deformation somewhat.