Electric dipole moments (EDM) of ionic atoms

Abstract

Recent investigations show that the second-order perturbation calculations of electric dipole moments (EDM) from the finite nuclear size as well as the relativistic effects are all canceled out by the third-order perturbation effects and that this is due to electron screening. To derive the nucleon EDM from the nucleus, we propose to measure the EDM of an ionic system. In this case, it is shown that the nucleon EDM can survive by the reduction factor of 1/Z for the ionic system with one electron stripped off.I. Introduction. It is well known that the electric dipole moments (EDM) of the point nucleus can be completely canceled out because of Schiff's theorem [1,2]. In addition, the EDM of the nucleus with the finite size effects can be also canceled out by electron screening [3,4]. In electron screening, the second-order perturbation calculation is canceled out by the third-order perturbation estimation because of the difference in perturbative interactions between the nucleus and the electrons. That is, like in perturbation theory, the EDM interaction is always the first order in the EDM coupling constant, and in third-order perturbation calculations electron screening can become as large as the second-order effects of the nucleon EDM; therefore they can cancel each other out. This suggests that there is no way to measure any nucleon EDM in the neutral atomic systems.However, there may well be some claim that nuclear EDM can be extracted from Schiff moments [5,6] using theoretical EDM calculations [7]. As we explain later, the physics of the Schiff moments originates from the EDM interactions between nucleons and atomic electrons, and the EDM energy can be obtained from the intermediate atomic excitation. However, the nucleon EDM from the Schiff moments vanishes when the nuclear state is in the s state, and if it is in the p state, the nuclear EDM d A is suppressed as d A 10 −6 d n . Therefore, it is practically impossible to extract any nuclear EDM from Schiff moments.Here, we first show that the nucleon EDM arising from any kind of nuclear EDM interactions is completely canceled out. In fact, the nuclear operator Z i

High-resolution spectroscopy on trapped molecular ions in rotating electric fields: A new approach for measuring the electron electric dipole moment

“…The ESR spectroscopy will be performed in the rotating frame. We note that this approach is conceptually related to efforts measuring electric dipole moments of charged particles in storage rings [47][48][49][50][51][52], but in our case the radius of the circular trajectory will be measured in millimeters, not meters. Precision spectroscopy in time-varying fields can be afflicted with novel sources of decoherence and systematic error, which will be discussed in Secs.…”

“…Our solution to this problem is to apply an electric field that rotates at radio frequencies. Under these conditions, the ions will still accelerate, however they will undergo circular motion similar to charged particles in a Penning trap [31][32][33] or storage ring [47][48][49][50][51][52]. The nuances of performing high-resolution electron spin resonance spectroscopy in this environment will be the main focus of this work, with the ultimate goal of demonstrating that such an experiment on the valence electrons in a ground or metastable 3 ∆ 1 level could prove to be a sensitive probe for a permanent electron electric dipole moment (eEDM).…”

Electric dipole moments of neutron-odd nuclei

“…can be reduced to (− Z i eR i • E ext ) which cancels out completely the original nuclear dipole operator [12][13][14][15]. Therefore, as long as we consider the nuclear EDM operator, we cannot observe the EDM of nucleon from the neutral atomic system.…”

Current trends in searches for new physics using measurements of parity violation and electric dipole moments in atoms and molecules

“…Different derivation of this formula can be found in Ref. [37,38]. Numerical calculations of the screened electric field inside an atomic ion were performed in a number of our works (see, e.g.…”