The Zel'dovich electric dipole moment in atoms

Dennis Edward Krause, Purdue University

Abstract

It is generally believed that both parity (P) and time reversal (T) invariance must be broken to produce a permanent electric dipole moment in a stable non-degenerate rotationally invariant system. However, Zel'dovich proposed that the P-violating weak interaction alone might be sufficient to produce an electric dipole moment in an unstable system, where the exponential decay law produces an "arrow of time" without explicit T-violation in the Hamiltonian. This "Zel'dovich moment" would be proportional to the linewidth of the unstable system. Subsequently, Bernreuther and Nachtmann explicitly calculated this Zel'dovich moment for deuterium. Here we use the master equation formalism to study the problem of the Zel'dovich moment. We apply a widely used master equation to a 3-level atom to obtain the results of Bernreuther and Nachtmann, and show that their effect may persist in steady-state situations. We then use a similar equation to study a 2-level atom, where we find an even more dramatic result. If true, it indicates that all atoms could have a Zel'dovich moment, even when they are in their ground states. We then show that these latter results are spurious--they arise because the master equation used neglected terms of the same order of magnitude as the Zel'dovich moment. When included, the Zel'dovich moment disappears in the 2-level atom. Since Bernreuther and Nachtmann's result was obtained in a similar manner, it is also called into question.

Degree

Ph.D.

Advisors

Fischbach, Purdue University.

Subject Area

Atoms & subatomic particles

COinS