Cavitation Density of Superfluid Helium-4 around 1 K

TL;DR

This study measures the cavitation density and pressure of superfluid helium-4 at around 1 K using optical interferometry, providing new insights into its negative pressure behavior and vortex effects.

Contribution

It presents the first precise measurement of cavitation density and pressure of superfluid helium-4 at near 1 K, highlighting discrepancies with previous experimental data.

Findings

Cavitation density measured as 0.1338 g/cm³

Cavitation pressure determined as -5.1 bar

Results align with vortex-inclusive models

Abstract

Using an optical interferomertric method, the homogeneous cavitation density of superfluid helium at $T=0.96\,$K is measured and found to be $\rho_{cav}=0.1338\pm0.0002\rm\,g.cm^{-3}$. A well established equation of state for liquid helium at negative pressures converts this to the cavitation pressure $P_{cav}=-5.1\pm0.1\,$bar. This cavitation pressure is consistent with a model taking into account the presence of quantized vortices, but disagrees with previously published experimental values of $P_{cav}$.