Axial phase of quantum fluids in nanotubes
  We explore the equations of state and other properties of various quantum fluids (3He, 4He, their mixtures, and H_2) confined within individual carbon nanotubes. Above a threshold number of particles, N_a, the fluid density near the axis begins to grow above a negligibly small value. The properties of this axial fluid phase are sensitive to the tube size and hence to the transverse compression in the case of a bundle of nanotubes. We consider He at zero temperature and H_2 at low temperatures. 
S. M. Gatica, G. Stan, M. M. Calbi, J. K. Johnson, and M. W. Cole