Violation of parity and time-reversal in atoms and molecules

Symmetries of the Universe have always provided theoreticians with a powerful tool in their efforts to understand and unify physics laws. Three of them have shaped physics over the last 50 years: parity (P), charge conjugation (C), and time-reversal (T). Today, T-violation remains the most mysterious symmetry violation as it is not understood properly and as much stronger T-violating mechanisms are required to explain the matter-antimatter in the Universe. T-violation could be potentially observed in some recently proposed and on-going experiments with atoms and molecules. In particular, T-violation could manifest itself in electric dipole moment (EDM) elemetary particles and atoms.; Here I present results of three calculations in support of emerging searches for T violation:; (1) A recently proposed experiment with liquid Xe at Princeton may significantly improve present limits on atomic EDM. We find that the liquid phase reduces the T-violating signal by only 40% still offering an improvement of several orders of magnitude to present limits for several sources of T-violation.; (2) To guide emerging searches for electron EDMs with molecular ions, we estimate the EDM-induced energy corrections for hydrogen halide ions HBr+ and HI+. We find that the EDM-signal for the two ions differ by an unexpectedly large factor of fifteen due to a dissimilarity in the nature of the chemical bond. We conclude HI+ ion may be a potentially competitive candidate for the EDM search. These observations provide guidelines for finding a even better molecular ion candidate.; (3) T-violation in an atom leads to the T-odd polarizability betaCP: a magnetic moment mu CP is induced by an electric field E0 applied to an atom, muCP = betaCP E0 . We estimate the T-violating polarizability for rare-gas atoms He through Rn. Finally, we evaluate a feasibility of setting a limit on electron EDM by measuring muCP of liquid Xe. We find that such an experiment could provide competitive bounds on electron EDM only if the present level of experimental sensitivity to ultra-weak magnetic fields is improved by several orders of magnitude.