Superfluidity in one and three dimensions has been studied for ${}^4\mathrm{He}$ fluid films adsorbed in nanopores which are straight channels and three-dimensionally connected pores, respectively. We observed the superfluid in one and three dimensions where thermal phonon wavelengths are much longer than the channel diameter and the period of the pore connection, respectively, and found that the superfluid onset depends on the pore connection. In the straight channels, the observed superfluid density disappears at a temperature far below the heat capacity anomaly of the Ginzburg-Landau transition, while in the pores connected in three dimension, the adsorbed ${}^4\mathrm{He}$ films show an evident three-dimensional transition where the superfluid onset occurs at the heat capacity peak.

• Received 30 August 2007

DOI:https://doi.org/10.1103/PhysRevLett.99.255301