Zero-Temperature Equation of State of Quasi-One-DimensionalH2

We have studied molecular hydrogen in a pure 1D geometry and inside a narrow carbon nanotube by means of the diffusion Monte Carlo method. The one dimensionality of ${\mathrm{H}}_{2}$ in the nanotube is well maintained in a large density range, this system being closer to an ideal 1D fluid than liquid ${}^{4}\mathrm{He}$ in the same setup. ${\mathrm{H}}_{2}$ shares with ${}^{4}\mathrm{He}$ the existence of a stable liquid phase and a quasicontinuous liquid-solid transition at very high linear densities.