Precision Measurement for Metastable Helium Atoms of the 413 nm Tune-Out Wavelength at Which the Atomic Polarizability Vanishes

TL;DR

This paper reports the first precise measurement of the tune-out wavelength for metastable helium atoms at 413.0938 nm, aligning well with theoretical predictions and enabling tests of quantum electrodynamics effects.

Contribution

It introduces a novel, highly sensitive technique for measuring the polarizability vanishing point in helium atoms, providing experimental data to test advanced theoretical models.

Findings

Measured tune-out wavelength: 413.0938 nm

Agreement with theoretical prediction: 413.02 nm

Supports further QED investigations

Abstract

We present the first measurement for helium atoms of the tune-out wavelength at which the atomic polarizability vanishes. We utilise a novel, highly sensitive technique for precisely measuring the effect of variations in the trapping potential of confined metastable ($2^{3}S_{1}$) helium atoms illuminated by a perturbing laser light field. The measured tune-out wavelength of 413.0938($9_{Stat.}$)($20_{Syst.}$) nm compares well with the value predicted by a theoretical calculation (413.02(9) nm) which is sensitive to finite nuclear mass, relativistic, and quantum electro-dynamic (QED) effects. This provides motivation for more detailed theoretical investigations to test QED.