Obtaining Atomic Matrix Elements from Vector Tune-Out Wavelengths using Atom Interferometry

TL;DR

This paper introduces a novel atom interferometry technique to measure tune-out wavelengths, enabling precise determination of atomic dipole matrix elements and improving the accuracy of parity violation experiments.

Contribution

It demonstrates how combined measurements of scalar and vector polarizabilities can refine atomic matrix element ratios, reducing errors in fundamental physics calculations.

Findings

Accurate tune-out wavelength measurements can constrain matrix element ratios.

Combined scalar and vector measurements distinguish core and tail state contributions.

Improved matrix element values enhance parity violation experiment accuracy.

Abstract

Accurate values for atomic dipole matrix elements are useful in many areas of physics, and in particular for interpreting experiments such as atomic parity violation. Obtaining accurate matrix element values is a challenge for both experiment and theory. A new technique that can be applied to this problem is tune-out spectroscopy, which is the measurement of light wavelengths where the electric polarizability of an atom has a zero. Using atom interferometry methods, tune-out wavelengths can be measured very accurately. Their values depend on the ratios of various dipole matrix elements and are thus useful for constraining theory and broadening the application of experimental values. Tune-out wavelength measurements to date have focused on zeros of the scalar polarizability, but in general the vector polarizability also contributes. We show here that combined measurements of the vector and scalar polarizabilities can provide more detailed information about the matrix element ratios, and in particular can distinguish small contributions from the atomic core and the valence tail states. These small contributions are the leading error sources in current parity violation calculations for cesium.