Optical measurement of the equation of state of bulk liquid helium-4 around 1 K

Using a stimulated Brillouin gain spectroscopy technique, we have measured the equation of state of bulk liquid helium-4 at similar to 1 K between 0 and 10 bars. Our results are in very good agreement with previous measurements and with theoretical equations of state. However, our specific method allows one to determine it on space/timescales as narrow as 35 mu m/190 ns. This technique is of particular interest for solving a remaining debate about the value of the homogeneous cavitation pressure of liquid He-4 at T similar to 1 K.

Automated summary

By utilizing stimulated Brillouin gain spectroscopy technique, the equation of state of bulk liquid helium-4 at around 1 K between 0 and 10 bars was measured, showing good agreement with previous measurements and theoretical equations. The specific method used allows for determination at narrow space/timescales of 35 μm/190 ns, which is useful for resolving debates about the homogeneous cavitation pressure of liquid helium-4 at similar temperatures.