Electric field on nucleus in solids and interaction of CP-violating nuclear electric dipole moment with phonons

Abstract

In atoms and molecules, electrons screen the nucleus from the external electric field. However, if the frequency of the electric field reaches the energy of atomic or molecular transition, the electric field at the nucleus may be resonantly enhanced by many orders in magnitude. In this paper, we study the mechanisms of screening or enhancement of electric field acting on the nuclei in solid states. We show that in dielectric crystals the phonon oscillations of the lattice play a crucial role for determining the electric field on nuclei within the MHz-THz region. As an application, we propose an experimental scheme for measuring the CP-violating nuclear electric dipole moment in a solid state based on the coherent excitation of acoustic phonons.

Electric dipole moments and the search for new physics

“…This intra-nuclear electric field interacts with the charge of a penetrating electron to produce energy shifts in the atom/molecule. This Schiff screening is also sidestepped by magnetic effects [203], imperfect screening of oscillating fields [204][205][206]. In addition, nuclei with spin I ≥ 1 obtain a CPV-induced magnetic quadrupole moment (MQM) that will interact with an unpaired electron spin.…”

Limits on CP-violating hadronic interactions and proton EDM from paramagnetic molecules

“…However, it can be measured through the nuclear Schiff moments and magnetic quadrupole moments [36][37][38], or by means of applying an oscillating electric field and observing nuclear spin rotations as argued in the refs. [39][40][41][42][43]. However, since the Schiff theorem applies only to a system which interacts electrically, the JHEP10(2020)077…”