Orientation-dependent hyperfine structure of polar molecules in a rare-gas matrix: a scheme for measuring the electron electric dipole moment

TL;DR

This paper proposes a method to measure the electron electric dipole moment by exploiting orientation-dependent hyperfine structure shifts in polar molecules embedded in rare-gas matrices, enabling selective detection based on molecular orientation.

Contribution

It introduces a scheme utilizing electric field-induced hyperfine shifts in rare-gas embedded polar molecules for improved EDM measurement.

Findings

Hyperfine structure is strongly perturbed by molecular orientation.

Electric fields cause orientation-dependent hyperfine shifts.

The method allows selective detection of molecular orientations.

Abstract

Because molecules can have their orientation locked when embedded into a solid rare-gas matrix, their hyperfine structure is strongly perturbed relative to the freely rotating molecule. The addition of an electric field further perturbs the structure, and fields parallel and antiparallel to the molecular orientation result in different shifts of the hyperfine structure. These shifts enable the selective detection of molecules with different orientations relative to the axes of a rare-gas crystal, which will be an important ingredient of an improved electron electric dipole moment measurement using large ensembles of polar molecules trapped in rare-gas matrices.