Quantum fluids in nanopores

TL;DR

This paper investigates the properties of quantum fluids like helium and hydrogen confined in nanotubes of various sizes, revealing phase transitions and strong binding effects in different confinement regimes.

Contribution

It provides new calculations on quantum fluids in nanotubes, detailing phase behaviors and binding energies across different pore sizes.

Findings

1D behavior in very small pores for helium.

Transition to shell phase in larger pores for H2.

Strong binding of cylindrical liquids $^4$He and $^3$He.

Abstract

We describe calculations of the properties of quantum fluids inside nanotubes of various sizes. Very small radius ($R$) pores confine the gases to a line, so that a one-dimensional (1D) approximation is applicable; the low temperature behavior of 1D $^4$He is discussed. Somewhat larger pores permit the particles to move off axis, resulting eventually in a transition to a cylindrical shell phase--a thin film near the tube wall; we explored this behavior for H$_2$. At even larger $R\sim 1$ nm, both the shell phase and an axial phase are present. Results showing strong binding of cylindrical liquids $^4$He and $^3$He are discussed.