LAUSR

We measured the superfluid response of 4He in a one-dimensional channel of 2.8 nm in diameter under unsaturated vapor pressure using a twofold torsional oscillator, and studied whether or not the superfluid response can be explained by the present Tomonaga–Luttinger (TL) liquid model down to the film region. For this system, the superfluid response is accompanied by a large dissipation throughout the film and liquid regions. We observed that the temperature of the dissipation peak is decreased by lowering the measuring frequency from 2 to 0.5 kHz, for a dilute liquid under unsaturated vapor pressure. Furthermore, the decrease becomes small with decreasing density from the pressurized to dilute liquid. On the other hand, no change in the dissipation peak temperature was observed in the film. The results show that, at least down to the liquid under unsaturated vapor pressure, the superfluid response can be explained by the TL liquid model. The dissipation peak itself varies continuously from the thin film t...