Black-Body Radiation Correction to the Polarizability of Helium

TL;DR

This paper calculates the black-body radiation correction to helium's polarizability, crucial for precise thermometry and fundamental constant determination, showing the effect is negligible at typical temperatures.

Contribution

It provides a precise theoretical calculation of the black-body radiation correction to helium's polarizability, highlighting its proportionality to a modified hyperpolarizability.

Findings

Correction is roughly proportional to a two-color hyperpolarizability.

The effect can be neglected in dielectric gas thermometry.

Numerical results confirm the correction's small magnitude.

Abstract

The correction to the polarizability of helium due to black-body radiation is calculated near room temperature. A precise theoretical determination of the black-body radiation correction to the polarizability of helium is essential for dielectric gas thermometry and for the determination of the Boltzmann constant. We find that the correction, for not too high temperature, is roughly proportional to a modified hyperpolarizability (two-color hyperpolarizability), which is different from the ordinary hyperpolarizability of helium. Our explicit calculations provide a definite numerical result for the effect and indicate that the effect of black-body radiation can be excluded as a limiting factor for dielectric gas thermometry using helium or argon.